chore(release): 4.3.0 [skip ci]

Also add `mathematics_max_values` and
`mathematics_min_values` to check in array.

.clang-format

@@ -1,2 +1,2 @@
-BasedOnStyle: 'Google'
+BasedOnStyle: "Google"
 ColumnLimit: 0

.github/ISSUE_TEMPLATE/BUG.md

@@ -1,8 +1,8 @@
 ---
-name: '🐛 Bug Report'
+name: "🐛 Bug Report"
-about: 'Report an unexpected problem or unintended behavior.'
+about: "Report an unexpected problem or unintended behavior."
-title: '[Bug]'
+title: "[Bug]"
-labels: 'bug'
+labels: "bug"
 ---
 
 <!--

.github/ISSUE_TEMPLATE/DOCUMENTATION.md

@@ -1,8 +1,8 @@
 ---
-name: '📜 Documentation'
+name: "📜 Documentation"
-about: 'Correct spelling errors, improvements or additions to documentation files (README, CONTRIBUTING...).'
+about: "Correct spelling errors, improvements or additions to documentation files (README, CONTRIBUTING...)."
-title: '[Documentation]'
+title: "[Documentation]"
-labels: 'documentation'
+labels: "documentation"
 ---
 
 <!-- Please make sure your issue has not already been fixed. -->

.github/ISSUE_TEMPLATE/FEATURE_REQUEST.md

@@ -1,8 +1,8 @@
 ---
-name: '✨ Feature Request'
+name: "✨ Feature Request"
-about: 'Suggest a new feature idea.'
+about: "Suggest a new feature idea."
-title: '[Feature]'
+title: "[Feature]"
-labels: 'feature request'
+labels: "feature request"
 ---
 
 <!-- Please make sure your issue has not already been fixed. -->

.github/ISSUE_TEMPLATE/IMPROVEMENT.md

@@ -1,8 +1,8 @@
 ---
-name: '🔧 Improvement'
+name: "🔧 Improvement"
-about: 'Improve structure/format/performance/refactor/tests of the code.'
+about: "Improve structure/format/performance/refactor/tests of the code."
-title: '[Improvement]'
+title: "[Improvement]"
-labels: 'improvement'
+labels: "improvement"
 ---
 
 <!-- Please make sure your issue has not already been fixed. -->

.github/ISSUE_TEMPLATE/QUESTION.md

@@ -1,8 +1,8 @@
 ---
-name: '🙋 Question'
+name: "🙋 Question"
-about: 'Further information is requested.'
+about: "Further information is requested."
-title: '[Question]'
+title: "[Question]"
-labels: 'question'
+labels: "question"
 ---
 
 ### Question

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,6 +1,6 @@
 <!-- Please first discuss the change you wish to make via issue before making a change. It might avoid a waste of your time. -->
 
-## What changes this PR introduce?
+# What changes this PR introduce?
 
 ## List any relevant issue numbers
 

.github/workflows/ci.yml

@@ -1,31 +1,40 @@
-name: 'CI'
+name: "CI"
 
 on:
   push:
     branches: [develop]
   pull_request:
-    branches: [master, develop]
+    branches: [main, develop]
 
 jobs:
   ci:
-    runs-on: 'ubuntu-latest'
+    runs-on: "ubuntu-latest"
     steps:
-      - uses: 'actions/checkout@v3.0.0'
+      - uses: "actions/checkout@v4.1.7"
 
-      - name: 'Install Build Tools'
+      - run: "sudo apt update"
-        run: 'sudo apt-get install --yes build-essential gcc make clang-format'
 
-      - run: 'make'
+      - name: "Install Build Tools"
-      - run: 'make run'
+        run: "sudo apt install --yes build-essential gcc make clang-format"
-      - run: 'make test'
+
-      - run: 'make lint'
+      - name: "Install Documentation Tools"
-      - run: 'make clean'
+        run: "sudo apt install --yes doxygen doxygen-gui doxygen-doc graphviz"
+
+      - run: "gcc --version"
+
+      - run: "make"
+      - run: "make run"
+      - run: "make test"
+      - run: "make lint"
+      - run: "make documentation"
+      - run: "make set_version"
+      - run: "make clean"
 
   lint-commit:
-      runs-on: 'ubuntu-latest'
+    runs-on: "ubuntu-latest"
     steps:
-        - uses: 'actions/checkout@v3.0.0'
+      - uses: "actions/checkout@v4.1.7"
         with:
           fetch-depth: 0
 
-        - uses: 'wagoid/commitlint-github-action@v5.3.0'
+      - uses: "wagoid/commitlint-github-action@v6.1.2"

.github/workflows/release.yml

@@ -1,51 +1,57 @@
-name: 'Release'
+name: "Release"
 
 on:
   push:
-    branches: [master]
+    branches: [main]
 
 jobs:
   release:
-    runs-on: 'ubuntu-latest'
+    runs-on: "ubuntu-latest"
     steps:
-      - uses: 'actions/checkout@v3.1.0'
+      - uses: "actions/checkout@v4.1.7"
         with:
           fetch-depth: 0
           persist-credentials: false
+          submodules: "recursive"
 
-      - name: 'Import GPG key'
+      - name: "Import GPG key"
-        uses: 'crazy-max/ghaction-import-gpg@v4'
+        uses: "crazy-max/ghaction-import-gpg@v6.1.0"
         with:
           gpg_private_key: ${{ secrets.GPG_PRIVATE_KEY }}
           git_user_signingkey: true
           git_commit_gpgsign: true
 
-      - name: 'Install Build Tools'
+      - run: "sudo apt update"
-        run: 'sudo apt-get install --yes build-essential gcc make clang-format doxygen doxygen-gui doxygen-doc graphviz'
 
-      - run: 'make set_version'
+      - name: "Install Build Tools"
+        run: "sudo apt install --yes build-essential gcc make clang-format"
 
-      - name: 'Generate Documentation'
+      - name: "Install Documentation Tools"
-        run: 'make documentation'
+        run: "sudo apt install --yes doxygen doxygen-gui doxygen-doc graphviz"
 
-      - name: 'Use Node.js'
+      - run: "make set_version"
-        uses: 'actions/setup-node@v3.1.0'
+
+      - name: "Use Node.js"
+        uses: "actions/setup-node@v4.0.3"
         with:
-          node-version: 'lts/*'
+          node-version: "20.17.0"
 
-      - name: 'Install Release Tools'
+      - name: "Install Release Tools"
-        run: 'npm install --save-dev semantic-release @commitlint/cli @commitlint/config-conventional @semantic-release/git @semantic-release/exec @saithodev/semantic-release-backmerge vercel'
+        run: "npm install --save-dev semantic-release@23.1.1 @commitlint/cli@19.5.0 @commitlint/config-conventional@19.5.0 @semantic-release/git@10.0.1 @semantic-release/exec@6.0.3 @saithodev/semantic-release-backmerge@4.0.1 vercel@37.4.2"
 
-      - run: 'rm --force package.json package-lock.json'
+      - run: "rm --force package.json package-lock.json"
 
-      - name: 'Release'
+      - name: "Release"
-        run: 'npx semantic-release'
+        run: "npx semantic-release"
         env:
           GH_TOKEN: ${{ secrets.GH_TOKEN }}
           GIT_COMMITTER_NAME: ${{ secrets.GIT_NAME }}
           GIT_COMMITTER_EMAIL: ${{ secrets.GIT_EMAIL }}
 
-      - name: 'Deploy to Vercel'
+      - name: "Generate Documentation"
+        run: "make documentation"
+
+      - name: "Deploy to Vercel"
         run: 'npx vercel ./documentation/html --token="${VERCEL_TOKEN}" --prod'
         env:
           VERCEL_TOKEN: ${{ secrets.VERCEL_TOKEN }}

.gitignore

@@ -4,6 +4,7 @@ documentation
 .vscode
 *.out
 *.o
-*.exe
 *.a
 node_modules
+package.json
+package-lock.json

.releaserc.json

@@ -1,5 +1,5 @@
 {
-  "branches": ["master"],
+  "branches": ["main"],
   "plugins": [
     [
       "@semantic-release/commit-analyzer",
@@ -16,7 +16,7 @@
     [
       "@semantic-release/exec",
       {
-        "prepareCmd": "make set_version && ./bin/set_version.exe ${nextRelease.version}"
+        "prepareCmd": "make set_version && ./bin/set_version ${nextRelease.version}"
       }
     ],
     [
@@ -30,7 +30,7 @@
     [
       "@saithodev/semantic-release-backmerge",
       {
-        "branches": [{ "from": "master", "to": "develop" }],
+        "branches": [{ "from": "main", "to": "develop" }],
         "backmergeStrategy": "merge"
       }
     ]

CODE_OF_CONDUCT.md

@@ -60,7 +60,7 @@ representative at an online or offline event.
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
 reported to the community leaders responsible for enforcement at
-contact@divlo.fr.
+<contact@theoludwig.fr>.
 All complaints will be reviewed and investigated promptly and fairly.
 
 All community leaders are obligated to respect the privacy and security of the

CONTRIBUTING.md

@@ -2,6 +2,14 @@
 
 Thanks a lot for your interest in contributing to **libcproject**! 🎉
 
+## Code of Conduct
+
+**libcproject** adopted the [Contributor Covenant](https://www.contributor-covenant.org/) as its Code of Conduct, and we expect project participants to adhere to it. Please read [the full text](./CODE_OF_CONDUCT.md) so that you can understand what actions will and will not be tolerated.
+
+## Open Development
+
+All work on **libcproject** happens directly on this repository. Both core team members and external contributors send pull requests which go through the same review process.
+
 ## Types of contributions
 
 - Reporting a bug.
@@ -11,7 +19,7 @@ Thanks a lot for your interest in contributing to **libcproject**! 🎉
 
 ## Pull Requests
 
-- **Please first discuss** the change you wish to make via [issue](https://github.com/Divlo/libcproject/issues) before making a change. It might avoid a waste of your time.
+- **Please first discuss** the change you wish to make via [issue](https://github.com/theoludwig/libcproject/issues) before making a change. It might avoid a waste of your time.
 
 - Ensure your code respect linting.
 
@@ -21,26 +29,19 @@ If you're adding new features to **libcproject**, please include tests.
 
 ## Commits
 
-The commit message guidelines respect [@commitlint/config-conventional](https://github.com/conventional-changelog/commitlint/tree/master/%40commitlint/config-conventional) and [Semantic Versioning](https://semver.org/) for releases.
+The commit message guidelines adheres to [Conventional Commits](https://www.conventionalcommits.org/) and [Semantic Versioning](https://semver.org/) for releases.
 
-### Types
+## Git Submodules
 
-Types define which kind of changes you made to the project.
+To get the submodule:
 
-| Types    | Description                                                                                                  |
+```sh
-| -------- | ------------------------------------------------------------------------------------------------------------ |
+git submodule update --init --recursive
-| feat     | A new feature.                                                                                               |
+```
-| fix      | A bug fix.                                                                                                   |
-| docs     | Documentation only changes.                                                                                  |
-| style    | Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc).      |
-| refactor | A code change that neither fixes a bug nor adds a feature.                                                   |
-| perf     | A code change that improves performance.                                                                     |
-| test     | Adding missing tests or correcting existing tests.                                                           |
-| build    | Changes that affect the build system or external dependencies (example scopes: gulp, broccoli, npm).         |
-| ci       | Changes to our CI configuration files and scripts (example scopes: Travis, Circle, BrowserStack, SauceLabs). |
-| chore    | Other changes that don't modify src or test files.                                                           |
-| revert   | Reverts a previous commit.                                                                                   |
 
-### Scopes
+To update the version:
 
-Scopes define what part of the code changed.
+```sh
+cd doxygen-awesome-css
+git checkout v2.3.3
+```

Doxyfile

@@ -1,6 +1,6 @@
 DOXYFILE_ENCODING = UTF-8
 PROJECT_NAME = libcproject
-PROJECT_BRIEF = "C static library easier to use than $(libc) (C standard library)."
+PROJECT_BRIEF = "C static library easier to use than libc (C standard library)."
 OUTPUT_DIRECTORY = documentation
 OUTPUT_LANGUAGE = English
 OPTIMIZE_OUTPUT_FOR_C = YES
@@ -8,11 +8,14 @@ INPUT = ./
 INPUT_ENCODING = UTF-8
 USE_MDFILE_AS_MAINPAGE = README.md
 FILE_PATTERNS = *.h \
-  README.md
+  README.md \
+  CODE_OF_CONDUCT.md \
+  CONTRIBUTING.md \
+  LICENSE
 HTML_EXTRA_STYLESHEET = doxygen-awesome-css/doxygen-awesome.css
 
 RECURSIVE = YES
-EXCLUDE = test doxygen-awesome-css
+EXCLUDE = test doxygen-awesome-css node_modules
 GENERATE_LATEX = NO
 GENERATE_TREEVIEW = YES
 EXAMPLE_PATTERNS = *

LICENSE

@@ -1,6 +1,6 @@
-MIT License
+# MIT License
 
-Copyright (c) Divlo
+Copyright (c) Théo LUDWIG <contact@theoludwig.fr>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

Makefile

@@ -1,6 +1,7 @@
 LIBRARY_NAME = libcproject
 CC = gcc
-CC_FLAGS = -Wall -Wextra -Wfloat-equal -Wundef -Werror -std=c17 -pedantic -pedantic-errors -I./
+CC_FLAGS = -Wall -Wextra -Wfloat-equal -Wundef -Werror -std=c17 -pedantic -pedantic-errors -O3 -I./
+CC_SANITIZER_FLAGS = -fsanitize=address -fsanitize=undefined
 LIB = ./build/${LIBRARY_NAME}.a
 LIB_CC_FLAGS = -L. -l:${LIB}
 LIB_SOURCES = $(wildcard lib/*.c)
@@ -8,34 +9,42 @@ LIB_OBJECTS = $(patsubst %.c, %.o, $(LIB_SOURCES))
 TEST_SOURCES = $(wildcard test/*.c)
 TEST_OBJECTS = $(patsubst %.c, %.o, $(TEST_SOURCES))
 HEADER_FILES = $(wildcard lib/*.h) $(wildcard test/*.h) ./${LIBRARY_NAME}.h
-MAIN_EXECUTABLE = bin/main.exe
+MAIN_EXECUTABLE = bin/main
-SET_VERSION_EXECUTABLE = bin/set_version.exe
+SET_VERSION_EXECUTABLE = bin/set_version
-TEST_EXECUTABLE = bin/test.exe
+TEST_EXECUTABLE = bin/test
-
-build/%.o: %.c
-	mkdir --parents ./build/lib ./build/test
-	${CC} ${CC_FLAGS} -c $< -o $@
 
 ${LIB}: $(addprefix build/, ${LIB_OBJECTS})
 	rm --force ${LIB}
 	ar -rcs ${LIB} $(addprefix build/, ${LIB_OBJECTS})
 
+build/lib:
+	mkdir --parents ./build/lib
+
+build/test:
+	mkdir --parents ./build/test
+
+build/lib/%.o: lib/%.c ${HEADER_FILES} | build/lib
+	${CC} ${CC_FLAGS} -c $< -o $@
+
+build/test/%.o: test/%.c ${HEADER_FILES} | build/test
+	${CC} ${CC_FLAGS} -c $< -o $@
+
 .PHONY: run
 run: ${LIB} ./main.c
 	mkdir --parents ./bin
-	${CC} ${CC_FLAGS} -o ${MAIN_EXECUTABLE} ./main.c ${LIB_CC_FLAGS}
+	${CC} ${CC_FLAGS} ${CC_SANITIZER_FLAGS} -o ${MAIN_EXECUTABLE} ./main.c ${LIB_CC_FLAGS}
 	./${MAIN_EXECUTABLE} ${ARGS}
 
 .PHONY: set_version
 set_version: ${LIB} ./set_version.c
 	mkdir --parents ./bin
-	${CC} ${CC_FLAGS} -o ${SET_VERSION_EXECUTABLE} ./set_version.c ${LIB_CC_FLAGS}
+	${CC} ${CC_FLAGS} ${CC_SANITIZER_FLAGS} -o ${SET_VERSION_EXECUTABLE} ./set_version.c ${LIB_CC_FLAGS}
 
 .PHONY: test
 test: ${LIB} $(addprefix build/, ${TEST_OBJECTS})
 	mkdir --parents ./bin
-	${CC} ${CC_FLAGS} -o ${TEST_EXECUTABLE} $(addprefix build/, ${TEST_OBJECTS}) ${LIB_CC_FLAGS}
+	${CC} ${CC_FLAGS} ${CC_SANITIZER_FLAGS} -o ${TEST_EXECUTABLE} $(addprefix build/, ${TEST_OBJECTS}) ${LIB_CC_FLAGS}
-	./${TEST_EXECUTABLE}
+	./${TEST_EXECUTABLE} ${ARGS}
 
 .PHONY: lint
 lint:

README.md

@@ -5,11 +5,11 @@
 </p>
 
 <p align="center">
-  <a href="./CONTRIBUTING.md"><img src="https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat" /></a>
+  <a href="./CONTRIBUTING.md"><img src="https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat" alt="Contributing" /></a>
   <a href="./LICENSE"><img src="https://img.shields.io/badge/licence-MIT-blue.svg" alt="Licence MIT"/></a>
   <a href="./CODE_OF_CONDUCT.md"><img src="https://img.shields.io/badge/Contributor%20Covenant-v2.0%20adopted-ff69b4.svg" alt="Contributor Covenant" /></a>
   <br />
-  <a href="https://github.com/Divlo/libcproject/actions/workflows/ci.yml"><img src="https://github.com/Divlo/libcproject/actions/workflows/ci.yml/badge.svg?branch=develop" /></a>
+  <a href="https://github.com/theoludwig/libcproject/actions/workflows/ci.yml"><img src="https://github.com/theoludwig/libcproject/actions/workflows/ci.yml/badge.svg?branch=develop" alt="CI" /></a>
   <a href="https://conventionalcommits.org"><img src="https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg" alt="Conventional Commits" /></a>
   <a href="https://github.com/semantic-release/semantic-release"><img src="https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg" alt="semantic-release" /></a>
 </p>
@@ -20,7 +20,7 @@
 
 C is a low-level programming language and we often end up reinventing the wheel as the C standard library (`libc`) is quite small and in my humble opinion, not well designed.
 
-**libcproject** solve this by providing common functions or data structures (`dictionary`, `linked_list`, `queue`, `stack`, etc.) we might need in our C projects.
+**libcproject** solve this by providing common functions or data structures (`hash_map`, `array_list`, `linked_list`, `queue`, `stack`, etc.), we might need in our C projects.
 
 [Online documentation](https://libcproject.vercel.app/).
 
@@ -30,14 +30,17 @@ C is a low-level programming language and we often end up reinventing the wheel
 - [GNU binutils](https://www.gnu.org/software/binutils/)
 - [GNU gcc](https://gcc.gnu.org/)
 - [GNU make](https://www.gnu.org/software/make/)
-- [clang-format](https://clang.llvm.org/docs/ClangFormat.html)
+- [ClangFormat](https://clang.llvm.org/docs/ClangFormat.html)
 - [Doxygen](https://www.doxygen.nl/)
 
 For example on GNU/Linux Ubuntu:
 
 ```sh
-sudo apt-get install build-essential gcc make clang-format
+# Install Build Tools
-sudo apt-get install doxygen doxygen-gui doxygen-doc graphviz
+sudo apt install build-essential gcc make clang-format
+
+# Install Documentation Tools
+sudo apt install doxygen doxygen-gui doxygen-doc graphviz
 ```
 
 ## Usage
@@ -55,31 +58,30 @@ nm ./build/libcproject.a # to see the symbols
 
 Steps to create a new C project that uses `libcproject`:
 
-### Step 1: Compile `libcproject`
+### Step 1: Create a new project
-
-```sh
-make
-```
-
-### Step 2: Create a new project
 
 ```sh
 mkdir my-project
 cd my-project
 ```
 
-### Step 3: Install `libcproject` in the project
+### Step 2: Install and Compile `libcproject` in the project
 
 ```sh
-mkdir libcproject
+# Clone the repository
-cp --recursive <path-to-libcproject> ./ # copy
+git clone git@github.com:theoludwig/libcproject.git
-# or
+
-ln -s <path-to-libcproject> ./ # symbolic link
+# Go to libcproject directory
+cd libcproject
+
+# Compile the library
+make
 ```
 
-### Step 4: Create a new C file
+### Step 3: Create a new C file
 
 ```sh
+cd ..
 touch main.c
 ```
 
@@ -90,17 +92,17 @@ touch main.c
 #include "libcproject/libcproject.h"
 
 int main() {
-  char* string = "Hello, world!";
+  string_t string = "Hello, world!"; // `string_t` is a typedef from `libcproject`
   printf("%s\n", string);
   printf("string_length = %ld\n", string_get_length(string)); // `string_get_length` is a function from `libcproject`
   return EXIT_SUCCESS;
 }
 ```
 
-### Step 5: Compile your project and link it with the library
+### Step 4: Compile your project and link it with the library
 
 ```sh
-gcc -o ./main.exe ./main.c -L. -l:./libcproject/build/libcproject.a
+gcc -o ./main ./main.c -L. -l:./libcproject/build/libcproject.a
 ```
 
 ## 💡 Contributing

lib/array_list.c

@@ -0,0 +1,44 @@
+#include "array_list.h"
+
+struct array_list* array_list_initialization() {
+  struct array_list* list = malloc(sizeof(struct array_list));
+  list->data = malloc(sizeof(void*) * ARRAY_LIST_INITIAL_CAPACITY);
+  list->size = 0;
+  list->capacity = ARRAY_LIST_INITIAL_CAPACITY;
+  return list;
+}
+
+void array_list_add(struct array_list* list, void* element) {
+  if (list->size >= list->capacity) {
+    size_t previous_capacity = list->capacity;
+    list->capacity += ARRAY_LIST_INITIAL_CAPACITY;
+    list->data = realloc(list->data, sizeof(void*) * list->capacity);
+    for (size_t index = previous_capacity; index < list->capacity; index++) {
+      list->data[index] = NULL;
+    }
+  }
+  list->data[list->size] = element;
+  list->size++;
+}
+
+void array_list_remove(struct array_list* list, size_t index) {
+  if (index >= list->size) {
+    return;
+  }
+  for (size_t i = index; i < list->size - 1; i++) {
+    list->data[i] = list->data[i + 1];
+  }
+  list->size--;
+}
+
+void* array_list_get(struct array_list* list, size_t index) {
+  if (index >= list->size) {
+    return NULL;
+  }
+  return list->data[index];
+}
+
+void array_list_free(struct array_list* list) {
+  free(list->data);
+  free(list);
+}

lib/array_list.h

@@ -0,0 +1,64 @@
+#ifndef __LIBCPROJECT_ARRAY_LIST__
+#define __LIBCPROJECT_ARRAY_LIST__
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "types.h"
+
+#define ARRAY_LIST_INITIAL_CAPACITY 10
+
+/**
+ * @brief A dynamic array implementation.
+ * @since v1.2.0
+ */
+struct array_list {
+  void** data;
+  size_t size;
+  size_t capacity;
+};
+
+/**
+ * @brief Initializes a new array list.
+ * @since v1.2.0
+ */
+struct array_list* array_list_initialization();
+
+/**
+ * @brief Adds an element to the end of the array list.
+ *
+ * @param list
+ * @param element
+ * @since v1.2.0
+ */
+void array_list_add(struct array_list* list, void* element);
+
+/**
+ * @brief Removes an element from the array list.
+ *
+ * @param list
+ * @param index
+ * @since v1.2.0
+ */
+void array_list_remove(struct array_list* list, size_t index);
+
+/**
+ * @brief Gets an element from the array list.
+ *
+ * @param list
+ * @param index
+ * @return void*
+ * @since v1.2.0
+ */
+void* array_list_get(struct array_list* list, size_t index);
+
+/**
+ * @brief Frees the array list.
+ *
+ * @param list
+ * @since v3.0.0
+ */
+void array_list_free(struct array_list* list);
+
+#endif

lib/character.c

@@ -1,16 +1,11 @@
 #include "character.h"
 
-#include <stdbool.h>
+void character_append(string_t string, const char character) {
-#include <stdlib.h>
-
-#include "string.h"
-
-void character_append(char* string, const char character) {
   size_t length = string_get_length(string);
   character_append_at(string, character, length);
 }
 
-void character_append_at(char* string, const char character, const size_t index) {
+void character_append_at(string_t string, const char character, const size_t index) {
   size_t length = string_get_length(string);
   for (size_t index_string = length; index_string > index; index_string--) {
     string[index_string] = string[index_string - 1];

lib/character.h

@@ -1,17 +1,22 @@
-#ifndef __CHARACTER__
+#ifndef __LIBCPROJECT_CHARACTER__
-#define __CHARACTER__
+#define __LIBCPROJECT_CHARACTER__
 
+#include <errno.h>
 #include <stdbool.h>
 #include <stdlib.h>
 
+#include "string.h"
+#include "types.h"
+
 /**
  * @brief Append a character to a string, assuming string points to an array
  * with enough space.
  *
  * @param string
  * @param character
+ * @since v1.0.0
  */
-void character_append(char* string, char character);
+void character_append(string_t string, char character);
 
 /**
  * @brief Append a character to a string at a specific index, assuming string points to an array with enough space.
@@ -19,14 +24,15 @@ void character_append(char* string, char character);
  * @param string
  * @param character
  * @param index
+ * @since v1.0.0
  */
-void character_append_at(char* string, const char character, const size_t index);
+void character_append_at(string_t string, const char character, const size_t index);
 
 /**
  * @brief Converts the character to uppercase.
  *
  * @param character
- * @return const char
+ * @since v1.0.0
  */
 char character_to_upper(const char character);
 
@@ -34,16 +40,17 @@ char character_to_upper(const char character);
  * @brief Converts the character to lowercase.
  *
  * @param character
- * @return const char
+ * @since v1.0.0
  */
 char character_to_lower(const char character);
 
 /**
  * @brief Check if the character is a digit ('0', '1', '2', '3', '4', '5', '6', '7, '8' or '9').
  *
- * @param string1
+ * @param character
- * @param string2
+ * @return true
- * @return true if the character is a digit, false otherwise
+ * @return false
+ * @since v1.0.0
  */
 bool character_get_is_digit(const char character);
 
@@ -52,7 +59,8 @@ bool character_get_is_digit(const char character);
  * Return 0 if the character is not a letter.
  *
  * @param character
- * @return char
+ * @return unsigned char
+ * @since v1.0.0
  */
 unsigned char character_get_alphabet_position(const char character);
 

lib/convert.c

@@ -1,19 +1,13 @@
 #include "convert.h"
 
-#include <stdio.h>
+string_t convert_character_to_string(const char character) {
-#include <stdlib.h>
+  string_t string = malloc(sizeof(char) * 2);
-
-#include "character.h"
-#include "mathematics.h"
-#include "stdbool.h"
-#include "string.h"
-
-char* convert_character_to_string(const char character) {
-  char* string = malloc(sizeof(char*) * 2);
   if (string == NULL) {
+    perror("Error (convert_character_to_string)");
     exit(EXIT_FAILURE);
   }
-  character_append(string, character);
+  string[0] = character;
+  string[1] = '\0';
   return string;
 }
 
@@ -25,7 +19,7 @@ char convert_digit_to_character(const char digit) {
   return digit + '0';
 }
 
-long long convert_string_to_number(const char* string) {
+long long convert_string_to_number(const string_t string) {
   bool is_negative = string[0] == '-';
   long long integer = 0;
   size_t length = string_get_length(string);
@@ -35,32 +29,40 @@ long long convert_string_to_number(const char* string) {
   return is_negative ? integer * -1 : integer;
 }
 
-char* convert_number_to_string(const long long integer) {
+string_t convert_number_to_string(const long long integer) {
   if (integer == 0) {
     return convert_character_to_string('0');
   }
   bool is_negative = integer < 0;
   size_t length = 1;
-  char* string = malloc(sizeof(char*) * length);
-  if (string == NULL) {
-    exit(EXIT_FAILURE);
-  }
   long long current = mathematics_absolute_value(integer);
   while (current != 0) {
-    character_append(string, convert_digit_to_character(current % 10));
     current = current / 10;
     length++;
-    string = realloc(string, sizeof(char*) * length);
   }
   if (is_negative) {
-    character_append(string, '-');
     length++;
-    string = realloc(string, sizeof(char*) * length);
   }
-  return string_reverse(string);
+  string_t string = malloc(sizeof(char) * length);
+  if (string == NULL) {
+    perror("Error (convert_number_to_string)");
+    exit(EXIT_FAILURE);
+  }
+  current = mathematics_absolute_value(integer);
+  size_t index = 0;
+  while (current != 0) {
+    string[index++] = convert_digit_to_character(current % 10);
+    current = current / 10;
+  }
+  if (is_negative) {
+    string[index++] = '-';
+  }
+  string[index] = '\0';
+  string_reverse(string);
+  return string;
 }
 
-char* convert_number_from_base_10_to_base(unsigned long long number, unsigned int base) {
+string_t convert_number_from_base_10_to_base(unsigned long long number, unsigned long base) {
   if (number == 0) {
     return "0";
   }
@@ -71,7 +73,7 @@ char* convert_number_from_base_10_to_base(unsigned long long number, unsigned in
     number = number / base;
     index++;
   }
-  char* result = malloc(sizeof(char) * (index + 1));
+  string_t result = malloc(sizeof(char) * (index + 1));
   int index_result = 0;
   for (int iteration = index - 1; iteration >= 0; iteration--) {
     int remainder = remainders[iteration];
@@ -82,13 +84,14 @@ char* convert_number_from_base_10_to_base(unsigned long long number, unsigned in
     }
     index_result++;
   }
+  result[index_result] = '\0';
   return result;
 }
 
-int convert_number_from_base_to_base_10(char* number, unsigned int base) {
+unsigned long convert_number_from_base_to_base_10(string_t number, unsigned long base) {
-  int length = string_get_length(number);
+  size_t length = string_get_length(number);
   int exponent = length - 1;
-  int result = 0;
+  unsigned long result = 0;
   int index = 0;
   while (exponent >= 0) {
     int current_number = (int)(number[index] - '0');
@@ -104,6 +107,6 @@ int convert_number_from_base_to_base_10(char* number, unsigned int base) {
   return result;
 }
 
-char* convert_number_from_base_to_another(char* number, int base_from, int base_target) {
+string_t convert_number_from_base_to_another(string_t number, unsigned long base_from, unsigned long base_target) {
   return convert_number_from_base_10_to_base(convert_number_from_base_to_base_10(number, base_from), base_target);
 }

lib/convert.h

@@ -1,20 +1,90 @@
-#ifndef __CONVERT__
+#ifndef __LIBCPROJECT_CONVERT__
-#define __CONVERT__
+#define __LIBCPROJECT_CONVERT__
 
-char* convert_character_to_string(const char character);
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
 
+#include "character.h"
+#include "mathematics.h"
+#include "stdbool.h"
+#include "string.h"
+#include "types.h"
+
+/**
+ * @brief Convert a character to a string.
+ *
+ * @param character
+ * @return string_t
+ * @since v1.0.0
+ */
+string_t convert_character_to_string(const char character);
+
+/**
+ * @brief Convert a character to a digit.
+ *
+ * @param character
+ * @return char
+ * @since v1.0.0
+ */
 char convert_character_to_digit(const char character);
 
+/**
+ * @brief Convert a digit to a character.
+ *
+ * @param digit
+ * @return char
+ * @since v1.0.0
+ */
 char convert_digit_to_character(const char digit);
 
-long long convert_string_to_number(const char* string);
+/**
+ * @brief Convert a string to a number.
+ *
+ * @param string
+ * @return long long
+ * @since v1.0.0
+ */
+long long convert_string_to_number(const string_t string);
 
-char* convert_number_to_string(const long long integer);
+/**
+ * @brief Convert a number to a string.
+ *
+ * @param integer
+ * @return string_t
+ * @since v1.0.0
+ */
+string_t convert_number_to_string(const long long integer);
 
-char* convert_number_from_base_10_to_base(unsigned long long number, unsigned int base);
+/**
+ * @brief Convert a number (base 10) to a string with a specific base.
+ *
+ * @param number
+ * @param base
+ * @return string_t
+ * @since v1.0.0
+ */
+string_t convert_number_from_base_10_to_base(unsigned long long number, unsigned long base);
 
-int convert_number_from_base_to_base_10(char* number, unsigned int base);
+/**
+ * @brief Convert a number with a specific base to a number base 10.
+ *
+ * @param number
+ * @param base
+ * @return int
+ * @since v1.0.0
+ */
+unsigned long convert_number_from_base_to_base_10(string_t number, unsigned long base);
 
-char* convert_number_from_base_to_another(char* number, int base_from, int base_target);
+/**
+ * @brief Convert a number with a specific base to a number of specific base.
+ *
+ * @param number
+ * @param base_from
+ * @param base_target
+ * @return string_t
+ * @since v1.0.0
+ */
+string_t convert_number_from_base_to_another(string_t number, unsigned long base_from, unsigned long base_target);
 
 #endif

lib/date.c

@@ -0,0 +1,287 @@
+#include "date.h"
+
+struct date *date_copy(struct date *date_to_copy) {
+  struct date *date = malloc(sizeof(struct date));
+  if (date == NULL) {
+    perror("Error (date_copy)");
+    exit(EXIT_FAILURE);
+  }
+  date->year = date_to_copy->year;
+  date->month = date_to_copy->month;
+  date->day = date_to_copy->day;
+  date->hours = date_to_copy->hours;
+  date->minutes = date_to_copy->minutes;
+  date->seconds = date_to_copy->seconds;
+  date->milliseconds = date_to_copy->milliseconds;
+  date->timezone_utc_offset = date_to_copy->timezone_utc_offset;
+  return date;
+}
+
+bool date_get_is_valid_year(uint16_t year) {
+  return year <= 9999;
+}
+
+bool date_get_is_valid_month(uint8_t month) {
+  return month >= 1 && month <= 12;
+}
+
+bool date_get_is_valid_day(uint8_t day) {
+  return day >= 1 && day <= 31;
+}
+
+bool date_get_is_valid_hours(uint8_t hours) {
+  return hours <= 23;
+}
+
+bool date_get_is_valid_minutes(uint8_t minutes) {
+  return minutes <= 59;
+}
+
+bool date_get_is_valid_seconds(uint8_t seconds) {
+  return seconds <= 59;
+}
+
+bool date_get_is_valid_milliseconds(uint16_t milliseconds) {
+  return milliseconds <= 999;
+}
+
+bool date_get_is_valid_timezone_utc_offset(int8_t timezone_utc_offset) {
+  return timezone_utc_offset >= -12 && timezone_utc_offset <= 14;
+}
+
+bool date_get_is_valid(struct date *date) {
+  size_t date_days_of_month = date_get_days_of_month(date->month, date->year);
+  return (date_get_is_valid_month(date->month) &&
+          date_get_is_valid_day(date->day) &&
+          date->day <= date_days_of_month &&
+          date_get_is_valid_hours(date->hours) &&
+          date_get_is_valid_minutes(date->minutes) &&
+          date_get_is_valid_seconds(date->seconds) &&
+          date_get_is_valid_milliseconds(date->milliseconds) &&
+          date_get_is_valid_timezone_utc_offset(date->timezone_utc_offset));
+}
+
+string_t date_to_iso_string(struct date *date_original) {
+  struct date *date = date_copy(date_original);
+  date_to_utc(date);
+
+  size_t iso_string_length = 24;
+  string_t result = malloc(sizeof(char) * (iso_string_length + 1));
+
+  string_t year_string = string_zero_pad(date->year, 4);
+  string_t month_string = string_zero_pad(date->month, 2);
+  string_t day_string = string_zero_pad(date->day, 2);
+  string_t hours_string = string_zero_pad(date->hours, 2);
+  string_t minutes_string = string_zero_pad(date->minutes, 2);
+  string_t seconds_string = string_zero_pad(date->seconds, 2);
+  string_t milliseconds_string = string_zero_pad(date->milliseconds, 3);
+  sprintf(result, "%s-%s-%sT%s:%s:%s.%sZ", year_string, month_string, day_string, hours_string, minutes_string, seconds_string, milliseconds_string);
+  free(year_string);
+  free(month_string);
+  free(day_string);
+  free(hours_string);
+  free(minutes_string);
+  free(seconds_string);
+  free(milliseconds_string);
+
+  free(date);
+  return result;
+}
+
+string_t date_to_iso_string_without_time(struct date *date) {
+  size_t iso_string_length = 10;
+  string_t result = malloc(sizeof(char) * (iso_string_length + 1));
+  if (result == NULL) {
+    perror("Error (date_to_iso_string_without_time)");
+    exit(EXIT_FAILURE);
+  }
+
+  string_t year_string = string_zero_pad(date->year, 4);
+  string_t month_string = string_zero_pad(date->month, 2);
+  string_t day_string = string_zero_pad(date->day, 2);
+  sprintf(result, "%s-%s-%s", year_string, month_string, day_string);
+  free(year_string);
+  free(month_string);
+  free(day_string);
+
+  return result;
+}
+
+struct date *date_from_iso_string(string_t iso_string) {
+  struct date *date = malloc(sizeof(struct date));
+  if (date == NULL) {
+    perror("Error (date_from_iso_string)");
+    exit(EXIT_FAILURE);
+  }
+
+  string_t year_string = string_substring(iso_string, 0, 3);
+  date->year = (uint16_t)convert_string_to_number(year_string);
+  free(year_string);
+
+  string_t month_string = string_substring(iso_string, 5, 6);
+  date->month = (uint8_t)convert_string_to_number(month_string);
+  free(month_string);
+
+  string_t day_string = string_substring(iso_string, 8, 9);
+  date->day = (uint8_t)convert_string_to_number(day_string);
+  free(day_string);
+
+  string_t hours_string = string_substring(iso_string, 11, 12);
+  date->hours = (uint8_t)convert_string_to_number(hours_string);
+  free(hours_string);
+
+  string_t minutes_string = string_substring(iso_string, 14, 15);
+  date->minutes = (uint8_t)convert_string_to_number(minutes_string);
+  free(minutes_string);
+
+  string_t seconds_string = string_substring(iso_string, 17, 18);
+  date->seconds = (uint8_t)convert_string_to_number(seconds_string);
+  free(seconds_string);
+
+  string_t milliseconds_string = string_substring(iso_string, 20, 22);
+  date->milliseconds = (uint16_t)convert_string_to_number(milliseconds_string);
+  free(milliseconds_string);
+
+  date->timezone_utc_offset = 0;
+
+  return date;
+}
+
+uint8_t date_get_days_of_month(uint8_t month, uint16_t year) {
+  switch (month) {
+    case 1:
+      return 31;
+    case 2:
+      return date_get_is_leap_year(year) ? 29 : 28;
+    case 3:
+      return 31;
+    case 4:
+      return 30;
+    case 5:
+      return 31;
+    case 6:
+      return 30;
+    case 7:
+      return 31;
+    case 8:
+      return 31;
+    case 9:
+      return 30;
+    case 10:
+      return 31;
+    case 11:
+      return 30;
+    case 12:
+      return 31;
+    default:
+      return 0;
+  }
+}
+
+bool date_get_is_leap_year(uint16_t year) {
+  return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
+}
+
+uint64_t date_convert_milliseconds_to_seconds(uint16_t milliseconds) {
+  return milliseconds / MILLISECONDS_PER_SECOND;
+}
+
+uint64_t date_convert_seconds_to_milliseconds(uint64_t seconds) {
+  return seconds * MILLISECONDS_PER_SECOND;
+}
+
+uint64_t date_convert_days_to_seconds(uint64_t days) {
+  return days * SECONDS_PER_DAY;
+}
+
+uint64_t date_convert_hms_to_seconds(uint8_t hours, uint8_t minutes, uint8_t seconds) {
+  return (hours * SECONDS_PER_HOUR) + (minutes * SECONDS_PER_MINUTE) + seconds;
+}
+
+uint64_t date_to_total_seconds(struct date *date) {
+  uint64_t total_seconds = 0;
+
+  for (uint16_t year = 0; year < date->year; year++) {
+    total_seconds += 365 * SECONDS_PER_DAY;
+    if (date_get_is_leap_year(year)) {
+      total_seconds += SECONDS_PER_DAY;
+    }
+  }
+
+  for (uint8_t month = 1; month < date->month; month++) {
+    total_seconds += date_convert_days_to_seconds(date_get_days_of_month(month, date->year));
+  }
+
+  total_seconds += date_convert_days_to_seconds(date->day - 1);
+  total_seconds += date_convert_hms_to_seconds(date->hours, date->minutes, date->seconds);
+
+  return total_seconds;
+}
+
+uint64_t date_duration_seconds_between_2_dates(struct date *date1, struct date *date2) {
+  struct date *utc_date1 = date_copy(date1);
+  struct date *utc_date2 = date_copy(date2);
+  date_to_utc(utc_date1);
+  date_to_utc(utc_date2);
+
+  uint64_t total_seconds_date1 = date_to_total_seconds(utc_date1);
+  uint64_t total_seconds_date2 = date_to_total_seconds(utc_date2);
+
+  free(utc_date1);
+  free(utc_date2);
+
+  return total_seconds_date1 > total_seconds_date2 ? total_seconds_date1 - total_seconds_date2 : total_seconds_date2 - total_seconds_date1;
+}
+
+void date_add_hours(struct date *date, int64_t hours) {
+  if (hours == 0) {
+    return;
+  }
+  int64_t total_hours = date->hours + hours;
+  int64_t additional_days = total_hours / 24;
+  int64_t new_hours = total_hours % 24;
+
+  if (new_hours < 0) {
+    new_hours += 24;
+    additional_days -= 1;
+  }
+
+  date->hours = (uint8_t)new_hours;
+
+  if (additional_days != 0) {
+    date->day += additional_days;
+
+    while (date->day > date_get_days_of_month(date->month, date->year)) {
+      date->day -= date_get_days_of_month(date->month, date->year);
+      date->month++;
+
+      if (date->month > 12) {
+        date->month = 1;
+        date->year++;
+      }
+    }
+
+    while (date->day < 1) {
+      date->month--;
+      if (date->month < 1) {
+        date->month = 12;
+        date->year--;
+      }
+
+      date->day += date_get_days_of_month(date->month, date->year);
+    }
+  }
+}
+
+void date_add_days(struct date *date, int64_t days) {
+  date_add_hours(date, days * 24);
+}
+
+void date_to_utc(struct date *date) {
+  if (date->timezone_utc_offset == 0) {
+    return;
+  }
+  int8_t timezone_utc_offset = date->timezone_utc_offset;
+  date->timezone_utc_offset = 0;
+  date_add_hours(date, mathematics_opposite(timezone_utc_offset));
+}

lib/date.h

@@ -0,0 +1,324 @@
+#ifndef __LIBCPROJECT_DATE__
+#define __LIBCPROJECT_DATE__
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "convert.h"
+#include "mathematics.h"
+#include "string.h"
+#include "types.h"
+
+#define SECONDS_PER_MINUTE 60
+#define SECONDS_PER_HOUR (60 * SECONDS_PER_MINUTE)
+#define SECONDS_PER_DAY (24 * SECONDS_PER_HOUR)
+#define MILLISECONDS_PER_SECOND 1000
+
+/**
+ * @brief Date object representing a single moment in time.
+ * @since v4.3.0
+ */
+struct date {
+  /**
+   * Year.
+   * Between [0, 9999] (inclusive).
+   * As per ISO 8601, a four-digit year [YYYY] and represents years from 0000 to 9999, year 0000 being equal to 1 BC and all others AD.
+   */
+  uint16_t year;
+
+  /**
+   * Month.
+   * Between [1, 12] (inclusive).
+   */
+  uint8_t month;
+
+  /**
+   * Day.
+   * Between [1, 31] (inclusive).
+   */
+  uint8_t day;
+
+  /**
+   * Hours.
+   * Between [0, 23] (inclusive).
+   */
+  uint8_t hours;
+
+  /**
+   * Minutes.
+   * Between [0, 59] (inclusive).
+   */
+  uint8_t minutes;
+
+  /**
+   * Seconds.
+   * Between [0, 59] (inclusive).
+   */
+  uint8_t seconds;
+
+  /**
+   * Milliseconds.
+   * Between [0, 999] (inclusive).
+   */
+  uint16_t milliseconds;
+
+  /**
+   * Timezone UTC offset.
+   * Between [-12, 14]
+   */
+  int8_t timezone_utc_offset;
+};
+
+/**
+ * @brief Return the copy of a date.
+ *
+ * @param date
+ * @return struct date*
+ * @since v4.3.0
+ */
+struct date *date_copy(struct date *date_to_copy);
+
+/**
+ * @brief Check if a year is valid, between [0, 9999] (inclusive).
+ *
+ * @param year
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_year(uint16_t year);
+
+/**
+ * @brief Check if a month is valid, between [1, 12] (inclusive).
+ *
+ * @param month
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_month(uint8_t month);
+
+/**
+ * @brief Check if a day is valid, between [1, 31] (inclusive).
+ *
+ * @param day
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_day(uint8_t day);
+
+/**
+ * @brief Check if hours are valid, between [0, 23] (inclusive).
+ *
+ * @param hours
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_hours(uint8_t hours);
+
+/**
+ * @brief Check if minutes are valid, between [0, 59] (inclusive).
+ *
+ * @param minutes
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_minutes(uint8_t minutes);
+
+/**
+ * @brief Check if seconds are valid, between [0, 59] (inclusive).
+ *
+ * @param seconds
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_seconds(uint8_t seconds);
+
+/**
+ * @brief Check if milliseconds are valid, between [0, 999] (inclusive).
+ *
+ * @param milliseconds
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_milliseconds(uint16_t milliseconds);
+
+/**
+ * @brief Check if the timezone UTC offset is valid, between [-12, 14] (inclusive).
+ *
+ * @param timezone_utc_offset
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid_timezone_utc_offset(int8_t timezone_utc_offset);
+
+/**
+ * @brief Check if the date is valid (all fields are possible).
+ *
+ * @param date
+ * @return bool
+ * @since v4.3.0
+ */
+bool date_get_is_valid(struct date *date);
+
+/**
+ * @brief String representing the date in the date time string format, a simplified format based on ISO 8601, which is always 24 characters long (`YYYY-MM-DDTHH:mm:ss.sssZ`). The timezone is always UTC, as denoted by the suffix `Z`.
+ *
+ * @param date
+ * @return string_t
+ *
+ * @code
+ * date_to_iso_string() // "2024-09-11T09:39:18.203Z"
+ * @endcode
+ *
+ * @since v4.3.0
+ */
+string_t date_to_iso_string(struct date *date);
+
+/**
+ * @brief String representing the date in the ISO 8601 format, without time information (`YYYY-MM-DD`).
+ *
+ * @param date
+ * @return string_t
+ *
+ * @code
+ * date_to_iso_string_without_time() // "2024-09-11"
+ * @endcode
+ *
+ * @since v4.3.0
+ */
+string_t date_to_iso_string_without_time(struct date *date);
+
+/**
+ * @brief Create a date from an ISO 8601 string, with the format `YYYY-MM-DDTHH:mm:ss.sssZ`.
+ *
+ * The timezone is always UTC, as denoted by the suffix `Z`.
+ *
+ * @param iso_string
+ * @return struct date*
+ * @since v4.3.0
+ */
+struct date *date_from_iso_string(string_t iso_string);
+
+/**
+ * @brief Get number of days in one month [1, 12].
+ *
+ * @param month
+ * @return uint8_t
+ * @since v4.3.0
+ */
+uint8_t date_get_days_of_month(uint8_t month, uint16_t year);
+
+/**
+ * @brief Determine if a year is a leap year.
+ *
+ * @param year
+ * @return bool
+ *
+ * @code
+ * date_is_leap_year(2020) // true
+ *
+ * date_is_leap_year(2021) // false
+ *
+ * date_is_leap_year(2022) // false
+ *
+ * date_is_leap_year(2023) // false
+ *
+ * date_is_leap_year(2024) // true
+ * @endcode
+ *
+ * @since v4.3.0
+ */
+bool date_get_is_leap_year(uint16_t year);
+
+/**
+ * @brief Convert milliseconds to seconds.
+ *
+ * @param milliseconds
+ * @return uint64_t
+ * @since v4.3.0
+ */
+uint64_t date_convert_milliseconds_to_seconds(uint16_t milliseconds);
+
+/**
+ * @brief Convert seconds to milliseconds.
+ *
+ * @param seconds
+ * @return uint64_t
+ * @since v4.3.0
+ */
+uint64_t date_convert_seconds_to_milliseconds(uint64_t seconds);
+
+/**
+ * @brief Convert days to seconds.
+ *
+ * @param days
+ * @return uint64_t
+ * @since v4.3.0
+ */
+uint64_t date_convert_days_to_seconds(uint64_t days);
+
+/**
+ * @brief Convert hours, minutes, and seconds to seconds.
+ *
+ * @param hours
+ * @param minutes
+ * @param seconds
+ * @return uint64_t
+ * @since v4.3.0
+ */
+uint64_t date_convert_hms_to_seconds(uint8_t hours, uint8_t minutes, uint8_t seconds);
+
+/**
+ * @brief Convert a date to total seconds.
+ *
+ * @param date
+ * @return uint64_t
+ * @since v4.3.0
+ */
+uint64_t date_to_total_seconds(struct date *date);
+
+/**
+ * @brief Calculate the duration in seconds between 2 dates.
+ *
+ * @param date1
+ * @param date2
+ * @return uint64_t
+ * @since v4.3.0
+ */
+uint64_t date_duration_seconds_between_2_dates(struct date *date1, struct date *date2);
+
+/**
+ * @brief Add hours to the date, managing the day, month, year changes if necessary.
+ *
+ * NOTE: Mutates the date.
+ *
+ * @param date
+ * @param hours
+ * @since v4.3.0
+ */
+void date_add_hours(struct date *date, int64_t hours);
+
+/**
+ * @brief Adds days to the date, managing month and year changes as needed.
+ *
+ * NOTE: Mutates the date.
+ *
+ * @param date The date to which days are being added.
+ * @param days The number of days to add.
+ * @since v4.3.0
+ */
+void date_add_days(struct date *date, int64_t days);
+
+/**
+ * @brief Transform the date with a Timezone UTC Offset to UTC (timezone_utc_offset = 0).
+ *
+ * NOTE: Mutates the date.
+ *
+ * @param date
+ * @since v4.3.0
+ */
+void date_to_utc(struct date *date);
+
+#endif

lib/dictionary.c

@@ -1,68 +0,0 @@
-#include "dictionary.h"
-
-#include <stdlib.h>
-
-#include "string.h"
-
-struct dictionary *dictionary_initialization() {
-  struct dictionary *dictionary = malloc(sizeof(struct dictionary));
-  dictionary->items = malloc(sizeof(struct dictionary_item *) * DICTIONARY_INITIAL_CAPACITY);
-  dictionary->length = 0;
-  dictionary->capacity = DICTIONARY_INITIAL_CAPACITY;
-  for (size_t index = 0; index < dictionary->capacity; index++) {
-    dictionary->items[index] = NULL;
-  }
-  return dictionary;
-}
-
-void dictionary_add(struct dictionary *dictionary, char *key, void *data) {
-  if (dictionary->length == dictionary->capacity) {
-    size_t previous_capacity = dictionary->capacity;
-    dictionary->capacity += DICTIONARY_INITIAL_CAPACITY;
-    dictionary->items = realloc(dictionary->items, sizeof(struct dictionary_item *) * dictionary->capacity);
-    for (size_t index = previous_capacity; index < dictionary->capacity; index++) {
-      dictionary->items[index] = NULL;
-    }
-  }
-  struct dictionary_item *item = NULL;
-  for (size_t index = 0; index < dictionary->length && item == NULL; index++) {
-    if (string_equals(key, dictionary->items[index]->key)) {
-      item = dictionary->items[index];
-    }
-  }
-  if (item == NULL) {
-    item = malloc(sizeof(struct dictionary_item));
-    item->key = key;
-    item->data = data;
-    dictionary->items[dictionary->length] = item;
-    dictionary->length++;
-  } else {
-    item->data = data;
-  }
-}
-
-void dictionary_remove(struct dictionary *dictionary, char *key) {
-  bool found = false;
-  for (size_t index = 0; index < dictionary->length && !found; index++) {
-    if (string_equals(key, dictionary->items[index]->key)) {
-      free(dictionary->items[index]);
-      dictionary->items[index] = dictionary->items[dictionary->length - 1];
-      dictionary->length--;
-      found = true;
-    }
-  }
-}
-
-struct dictionary_item *dictionary_get(struct dictionary *dictionary, char *key) {
-  for (size_t index = 0; index < dictionary->length; index++) {
-    struct dictionary_item *item = dictionary->items[index];
-    if (string_equals(key, item->key)) {
-      return item;
-    }
-  }
-  return NULL;
-}
-
-bool dictionary_contains_key(struct dictionary *dictionary, char *key) {
-  return dictionary_get(dictionary, key) != NULL;
-}

lib/dictionary.h

@@ -1,34 +0,0 @@
-#ifndef __DICTIONARY__
-#define __DICTIONARY__
-
-#include <stdbool.h>
-#include <stdlib.h>
-
-#include "linked_list.h"
-
-#define DICTIONARY_INITIAL_CAPACITY 10
-
-// Dictionary implementation with O(n) lookup complexity.
-struct dictionary {
-  struct dictionary_item **items;
-
-  size_t length;
-  size_t capacity;
-};
-
-struct dictionary_item {
-  void *data;
-  char *key;
-};
-
-struct dictionary *dictionary_initialization();
-
-void dictionary_add(struct dictionary *dictionary, char *key, void *data);
-
-void dictionary_remove(struct dictionary *dictionary, char *key);
-
-struct dictionary_item *dictionary_get(struct dictionary *dictionary, char *key);
-
-bool dictionary_contains_key(struct dictionary *dictionary, char *key);
-
-#endif

lib/filesystem.c

@@ -1,17 +1,6 @@
 #include "filesystem.h"
 
-#include <dirent.h>
+int filesystem_read(string_t path, byte_t **file_content, off_t *file_size) {
-#include <errno.h>
-#include <fcntl.h>
-#include <pwd.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include "string.h"
-
-int filesystem_read(char *path, char **file_content, off_t *file_size) {
   int file_descriptor = open(path, O_RDONLY);
   if (file_descriptor == -1) {
     return -1;
@@ -19,39 +8,243 @@ int filesystem_read(char *path, char **file_content, off_t *file_size) {
   (*file_size) = lseek(file_descriptor, 0, SEEK_END);
   lseek(file_descriptor, 0, SEEK_SET);
   (*file_content) = malloc(*file_size);
-  read(file_descriptor, *file_content, *file_size);
+  if (read(file_descriptor, *file_content, *file_size) == -1) {
+    return -1;
+  }
   close(file_descriptor);
   return 0;
 }
 
-int filesystem_write(char *path, char *file_content, off_t file_size) {
+int filesystem_write(string_t path, byte_t *file_content, off_t file_size) {
   int file_descriptor = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
   if (file_descriptor == -1) {
     return -1;
   }
-  write(file_descriptor, file_content, file_size);
+  if (write(file_descriptor, file_content, file_size) == -1) {
+    return -1;
+  }
   close(file_descriptor);
   return 0;
 }
 
-char *filesystem_get_mimetype(char *path) {
+bool filesystem_exists(string_t path) {
-  if (string_ends_with(path, ".html")) {
+  return access(path, F_OK) == 0;
-    return "text/html";
+}
+
+int filesystem_remove(string_t path) {
+  return remove(path);
+}
+
+string_t filesystem_get_mimetype(string_t path) {
+  if (string_ends_with(path, ".aac")) {
+    return "audio/aac";
+  }
+  if (string_ends_with(path, ".abw")) {
+    return "application/x-abiword";
+  }
+  if (string_ends_with(path, ".arc")) {
+    return "application/x-freearc";
+  }
+  if (string_ends_with(path, ".avif")) {
+    return "image/avif";
+  }
+  if (string_ends_with(path, ".avi")) {
+    return "video/x-msvideo";
+  }
+  if (string_ends_with(path, ".azw")) {
+    return "application/vnd.amazon.ebook";
+  }
+  if (string_ends_with(path, ".bin")) {
+    return "application/octet-stream";
+  }
+  if (string_ends_with(path, ".bmp")) {
+    return "image/bmp";
+  }
+  if (string_ends_with(path, ".bz")) {
+    return "application/x-bzip";
+  }
+  if (string_ends_with(path, ".bz2")) {
+    return "application/x-bzip2";
+  }
+  if (string_ends_with(path, ".cda")) {
+    return "application/x-cdf";
+  }
+  if (string_ends_with(path, ".csh")) {
+    return "application/x-csh";
   }
   if (string_ends_with(path, ".css")) {
     return "text/css";
   }
-  if (string_ends_with(path, ".js")) {
+  if (string_ends_with(path, ".csv")) {
-    return "text/javascript";
+    return "text/csv";
   }
-  if (string_ends_with(path, ".png")) {
+  if (string_ends_with(path, ".doc")) {
-    return "image/png";
+    return "application/msword";
   }
-  if (string_ends_with(path, ".jpg") || string_ends_with(path, ".jpeg")) {
+  if (string_ends_with(path, ".docx")) {
-    return "image/jpeg";
+    return "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
+  }
+  if (string_ends_with(path, ".eot")) {
+    return "application/vnd.ms-fontobject";
+  }
+  if (string_ends_with(path, ".epub")) {
+    return "application/epub+zip";
+  }
+  if (string_ends_with(path, ".gz")) {
+    return "application/gzip";
   }
   if (string_ends_with(path, ".gif")) {
     return "image/gif";
   }
+  if (string_ends_with(path, ".htm") || string_ends_with(path, ".html")) {
+    return "text/html";
+  }
+  if (string_ends_with(path, ".ico")) {
+    return "image/vnd.microsoft.icon";
+  }
+  if (string_ends_with(path, ".ics")) {
+    return "text/calendar";
+  }
+  if (string_ends_with(path, ".jar")) {
+    return "application/java-archive";
+  }
+  if (string_ends_with(path, ".jpg") || string_ends_with(path, ".jpeg") || string_ends_with(path, ".jpe") || string_ends_with(path, ".jif") || string_ends_with(path, ".jfif") || string_ends_with(path, ".jfi")) {
+    return "image/jpeg";
+  }
+  if (string_ends_with(path, ".js") || string_ends_with(path, ".mjs") || string_ends_with(path, ".cjs")) {
+    return "text/javascript";
+  }
+  if (string_ends_with(path, ".json")) {
+    return "application/json";
+  }
+  if (string_ends_with(path, ".jsonld")) {
+    return "application/ld+json";
+  }
+  if (string_ends_with(path, ".mid") || string_ends_with(path, ".midi")) {
+    return "audio/midi";
+  }
+  if (string_ends_with(path, ".mp3")) {
+    return "audio/mpeg";
+  }
+  if (string_ends_with(path, ".mp4")) {
+    return "video/mp4";
+  }
+  if (string_ends_with(path, ".mpeg")) {
+    return "video/mpeg";
+  }
+  if (string_ends_with(path, ".mpkg")) {
+    return "application/vnd.apple.installer+xml";
+  }
+  if (string_ends_with(path, ".odp")) {
+    return "application/vnd.oasis.opendocument.presentation";
+  }
+  if (string_ends_with(path, ".ods")) {
+    return "application/vnd.oasis.opendocument.spreadsheet";
+  }
+  if (string_ends_with(path, ".odt")) {
+    return "application/vnd.oasis.opendocument.text";
+  }
+  if (string_ends_with(path, ".oga")) {
+    return "audio/ogg";
+  }
+  if (string_ends_with(path, ".ogv")) {
+    return "video/ogg";
+  }
+  if (string_ends_with(path, ".ogx")) {
+    return "application/ogg";
+  }
+  if (string_ends_with(path, ".opus")) {
+    return "audio/opus";
+  }
+  if (string_ends_with(path, ".otf")) {
+    return "font/otf";
+  }
+  if (string_ends_with(path, ".png")) {
+    return "image/png";
+  }
+  if (string_ends_with(path, ".pdf")) {
+    return "application/pdf";
+  }
+  if (string_ends_with(path, ".php")) {
+    return "application/x-httpd-php";
+  }
+  if (string_ends_with(path, ".ppt")) {
+    return "application/vnd.ms-powerpoint";
+  }
+  if (string_ends_with(path, ".pptx")) {
+    return "application/vnd.openxmlformats-officedocument.presentationml.presentation";
+  }
+  if (string_ends_with(path, ".rar")) {
+    return "application/vnd.rar";
+  }
+  if (string_ends_with(path, ".rtf")) {
+    return "application/rtf";
+  }
+  if (string_ends_with(path, ".sh")) {
+    return "application/x-sh";
+  }
+  if (string_ends_with(path, ".svg")) {
+    return "image/svg+xml";
+  }
+  if (string_ends_with(path, ".tar")) {
+    return "application/x-tar";
+  }
+  if (string_ends_with(path, ".tif") || string_ends_with(path, ".tiff")) {
+    return "image/tiff";
+  }
+  if (string_ends_with(path, ".ts")) {
+    return "application/typescript";
+  }
+  if (string_ends_with(path, ".ttf")) {
+    return "font/ttf";
+  }
+  if (string_ends_with(path, ".txt")) {
     return "text/plain";
   }
+  if (string_ends_with(path, ".vsd")) {
+    return "application/vnd.visio";
+  }
+  if (string_ends_with(path, ".wav")) {
+    return "audio/wav";
+  }
+  if (string_ends_with(path, ".weba") || string_ends_with(path, ".webm")) {
+    return "audio/webm";
+  }
+  if (string_ends_with(path, ".webp")) {
+    return "image/webp";
+  }
+  if (string_ends_with(path, ".woff")) {
+    return "font/woff";
+  }
+  if (string_ends_with(path, ".woff2")) {
+    return "font/woff2";
+  }
+  if (string_ends_with(path, ".xhtml")) {
+    return "application/xhtml+xml";
+  }
+  if (string_ends_with(path, ".xls")) {
+    return "application/vnd.ms-excel";
+  }
+  if (string_ends_with(path, ".xlsx")) {
+    return "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
+  }
+  if (string_ends_with(path, ".xml")) {
+    return "application/xml";
+  }
+  if (string_ends_with(path, ".xul")) {
+    return "application/vnd.mozilla.xul+xml";
+  }
+  if (string_ends_with(path, ".zip")) {
+    return "application/zip";
+  }
+  if (string_ends_with(path, ".3gp")) {
+    return "video/3gpp";
+  }
+  if (string_ends_with(path, ".3g2")) {
+    return "video/3gpp2";
+  }
+  if (string_ends_with(path, ".7z")) {
+    return "application/x-7z-compressed";
+  }
+  return "application/octet-stream";
+}

lib/filesystem.h

@@ -1,19 +1,30 @@
-#ifndef __FILESYSTEM__
+#ifndef __LIBCPROJECT_FILESYSTEM__
-#define __FILESYSTEM__
+#define __LIBCPROJECT_FILESYSTEM__
 
+#include <dirent.h>
+#include <errno.h>
 #include <fcntl.h>
+#include <pwd.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "string.h"
+#include "types.h"
 
 /**
  * @brief Read the content of a file.
  *
  * @param path
  * @param file_content
- * @param file_size
+ * @param file_size The size of the file that was read (mutated by the function).
+ * @retval -1 if the file does not exist or if there is an error.
+ * @retval 0 for success.
  * @return int
- * @retval -1 if the file does not exist
+ * @since v1.0.0
- * @retval 0 for success
  */
-int filesystem_read(char *path, char **file_content, off_t *file_size);
+int filesystem_read(string_t path, byte_t **file_content, off_t *file_size);
 
 /**
  * @brief Write the content to a file.
@@ -21,18 +32,44 @@ int filesystem_read(char *path, char **file_content, off_t *file_size);
  * @param path
  * @param file_content
  * @param file_size
+ * @retval -1 if there is an error.
+ * @retval 0 for success.
  * @return int
- * @retval -1 if errors
+ * @since v1.0.0
- * @retval 0 for success
  */
-int filesystem_write(char *path, char *file_content, off_t file_size);
+int filesystem_write(string_t path, byte_t *file_content, off_t file_size);
 
 /**
- * @brief Get the mimetype of a file.
+ * @brief Check if a path exists.
  *
  * @param path
- * @return char*
+ * @return true
+ * @return false
+ * @since v3.1.0
  */
-char *filesystem_get_mimetype(char *path);
+bool filesystem_exists(string_t path);
+
+/**
+ * @brief Removes a path.
+ *
+ * @param path
+ * @return int
+ * @retval -1 if there is an error.
+ * @retval 0 for success.
+ * @return int
+ * @since v3.1.0
+ */
+int filesystem_remove(string_t path);
+
+/**
+ * @brief Get the mimetype of a file based on its extension.
+ *
+ * @param path
+ * @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
+ * @see https://www.iana.org/assignments/media-types/media-types.xhtml
+ * @return string_t
+ * @since v1.0.0
+ */
+string_t filesystem_get_mimetype(string_t path);
 
 #endif

lib/hash_map.c

@@ -0,0 +1,244 @@
+#include "hash_map.h"
+
+#define ROTATE_LEFT(x, b) (((x) << (b)) | ((x) >> (64 - (b))))
+
+uint64_t sip_round(uint64_t v0, uint64_t v1, uint64_t v2, uint64_t v3) {
+  v0 += v1;
+  v2 += v3;
+  v1 = ROTATE_LEFT(v1, 13);
+  v3 = ROTATE_LEFT(v3, 16);
+  v1 ^= v0;
+  v3 ^= v2;
+  v0 = ROTATE_LEFT(v0, 32);
+  v2 += v1;
+  v0 += v3;
+  v1 = ROTATE_LEFT(v1, 17);
+  v3 = ROTATE_LEFT(v3, 21);
+  v1 ^= v2;
+  v3 ^= v0;
+  v2 = ROTATE_LEFT(v2, 32);
+  return v0;
+}
+
+uint64_t hash(string_t key, size_t capacity) {
+  size_t key_length = string_get_length(key);
+  const uint64_t c = 0x736f6d6570736575;
+  uint64_t v0 = c ^ 0x736f6d6570736575;
+  uint64_t v1 = c ^ 0x646f72616e646f6d;
+  uint64_t v2 = c ^ 0x6c7967656e657261;
+  uint64_t v3 = c ^ 0x7465646279746573;
+
+  uint64_t m;
+  uint64_t hash;
+
+  uint8_t *message = (uint8_t *)key;
+
+  size_t remaining = key_length;
+  size_t offset = 0;
+
+  while (remaining >= 8) {
+    memcpy(&m, message + offset, sizeof(uint64_t));
+    v3 ^= m;
+
+    for (int i = 0; i < 2; i++) {
+      v0 = sip_round(v0, v1, v2, v3);
+      v1 = ROTATE_LEFT(v1, 13);
+      v2 = ROTATE_LEFT(v2, 16);
+      v3 = ROTATE_LEFT(v3, 32);
+      v0 ^= m;
+    }
+
+    v2 ^= 0xff;
+    for (int i = 0; i < 4; i++) {
+      v0 = sip_round(v0, v1, v2, v3);
+      v1 = ROTATE_LEFT(v1, 13);
+      v2 = ROTATE_LEFT(v2, 16);
+      v3 = ROTATE_LEFT(v3, 32);
+    }
+
+    hash = v0 ^ v1 ^ v2 ^ v3;
+    remaining -= sizeof(uint64_t);
+    offset += sizeof(uint64_t);
+  }
+
+  m = (uint64_t)remaining << 56;
+  switch (remaining) {
+    case 7:
+      m |= (uint64_t)message[offset + 6] << 48;
+      break;
+    case 6:
+      m |= (uint64_t)message[offset + 5] << 40;
+      break;
+    case 5:
+      m |= (uint64_t)message[offset + 4] << 32;
+      break;
+    case 4:
+      m |= (uint64_t)message[offset + 3] << 24;
+      break;
+    case 3:
+      m |= (uint64_t)message[offset + 2] << 16;
+      break;
+    case 2:
+      m |= (uint64_t)message[offset + 1] << 8;
+      break;
+    case 1:
+      m |= (uint64_t)message[offset];
+      break;
+    default:
+      break;
+  }
+
+  v3 ^= m;
+
+  for (int i = 0; i < 2; i++) {
+    v0 = sip_round(v0, v1, v2, v3);
+    v1 = ROTATE_LEFT(v1, 13);
+    v2 = ROTATE_LEFT(v2, 16);
+    v3 = ROTATE_LEFT(v3, 32);
+  }
+
+  v0 ^= m;
+  v2 ^= 0xff;
+
+  for (int i = 0; i < 4; i++) {
+    v0 = sip_round(v0, v1, v2, v3);
+    v1 = ROTATE_LEFT(v1, 13);
+    v2 = ROTATE_LEFT(v2, 16);
+    v3 = ROTATE_LEFT(v3, 32);
+  }
+
+  hash = v0 ^ v1 ^ v2 ^ v3;
+
+  return hash % capacity;
+}
+
+struct hash_map *hash_map_initialization() {
+  struct hash_map *hash_map = malloc(sizeof(struct hash_map));
+  hash_map->items = malloc(sizeof(struct linked_list *) * HASH_MAP_INITIAL_CAPACITY);
+  hash_map->length = 0;
+  hash_map->capacity = HASH_MAP_INITIAL_CAPACITY;
+  for (size_t index = 0; index < hash_map->capacity; index++) {
+    hash_map->items[index] = NULL;
+  }
+  return hash_map;
+}
+
+void hash_map_add(struct hash_map *hash_map, string_t key_value, void *data) {
+  if (hash_map->length == hash_map->capacity) {
+    size_t previous_capacity = hash_map->capacity;
+    hash_map->capacity += HASH_MAP_INITIAL_CAPACITY;
+    hash_map->items = realloc(hash_map->items, sizeof(struct linked_list *) * hash_map->capacity);
+    for (size_t index = previous_capacity; index < hash_map->capacity; index++) {
+      hash_map->items[index] = NULL;
+    }
+  }
+  string_t key = string_copy(key_value);
+  uint64_t hash_value = hash(key, hash_map->capacity);
+  struct linked_list *list = hash_map->items[hash_value];
+  struct hash_map_item *item = malloc(sizeof(struct hash_map_item));
+  item->key = key;
+  item->data = data;
+  if (list == NULL) {
+    list = linked_list_initialization();
+    hash_map->items[hash_value] = list;
+    linked_list_add_in_head(list, (void *)item);
+    hash_map->length++;
+  } else {
+    struct linked_list_node *node = list->head;
+    bool found = false;
+    while (node != NULL && !found) {
+      struct hash_map_item *item = (struct hash_map_item *)node->data;
+      if (string_equals(key, item->key)) {
+        item->data = data;
+        found = true;
+      }
+      node = node->next;
+    }
+    if (!found) {
+      linked_list_add_in_head(list, (void *)item);
+      hash_map->length++;
+    } else {
+      free(key);
+      free(item);
+    }
+  }
+}
+
+void hash_map_remove(struct hash_map *hash_map, string_t key) {
+  uint64_t hash_value = hash(key, hash_map->capacity);
+  struct linked_list *list = hash_map->items[hash_value];
+  if (list == NULL) {
+    return;
+  }
+  struct linked_list *new_list = linked_list_initialization();
+  struct linked_list_node *node = list->head;
+  while (node != NULL) {
+    struct hash_map_item *item = (struct hash_map_item *)node->data;
+    if (!string_equals(key, item->key)) {
+      linked_list_add_in_head(new_list, item);
+    } else {
+      free(item->key);
+      free(item);
+    }
+    node = node->next;
+  }
+  linked_list_free(list);
+  hash_map->items[hash_value] = new_list;
+  hash_map->length--;
+}
+
+void *hash_map_get(struct hash_map *hash_map, string_t key) {
+  uint64_t hash_value = hash(key, hash_map->capacity);
+  struct linked_list *list = hash_map->items[hash_value];
+  if (list == NULL) {
+    return NULL;
+  }
+  struct linked_list_node *node = list->head;
+  while (node != NULL) {
+    struct hash_map_item *item = (struct hash_map_item *)node->data;
+    if (string_equals(key, item->key)) {
+      return item->data;
+    }
+    node = node->next;
+  }
+  return NULL;
+}
+
+bool hash_map_contains_key(struct hash_map *hash_map, string_t key) {
+  return hash_map_get(hash_map, key) != NULL;
+}
+
+string_t *hash_map_get_keys(struct hash_map *hash_map) {
+  string_t *keys = malloc(sizeof(string_t) * hash_map->length);
+  size_t index = 0;
+  for (size_t hash_value = 0; hash_value < hash_map->capacity; hash_value++) {
+    struct linked_list *list = hash_map->items[hash_value];
+    if (list != NULL) {
+      struct linked_list_node *node = list->head;
+      while (node != NULL) {
+        struct hash_map_item *item = (struct hash_map_item *)node->data;
+        keys[index++] = item->key;
+        node = node->next;
+      }
+    }
+  }
+  return keys;
+}
+
+void hash_map_free(struct hash_map *hash_map) {
+  for (size_t index = 0; index < hash_map->capacity; index++) {
+    struct linked_list *list = hash_map->items[index];
+    if (list != NULL) {
+      struct linked_list_node *node = list->head;
+      while (node != NULL) {
+        struct hash_map_item *item = (struct hash_map_item *)node->data;
+        free(item->key);
+        free(item);
+        node = node->next;
+      }
+      linked_list_free(list);
+    }
+  }
+  free(hash_map->items);
+  free(hash_map);
+}

lib/hash_map.h

@@ -0,0 +1,111 @@
+#ifndef __LIBCPROJECT_HASH_MAP__
+#define __LIBCPROJECT_HASH_MAP__
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "linked_list.h"
+#include "string.h"
+#include "types.h"
+
+#define HASH_MAP_INITIAL_CAPACITY 10
+
+/**
+ * @brief Hash map data structure.
+ * @since v2.0.0
+ */
+struct hash_map {
+  struct linked_list **items;
+
+  size_t length;
+  size_t capacity;
+};
+
+/**
+ * @brief Hash map item data structure.
+ * @since v2.0.0
+ */
+struct hash_map_item {
+  void *data;
+  string_t key;
+};
+
+/**
+ * @brief Hash function (using SipHash 1-3 algorithm).
+ * @see https://en.wikipedia.org/wiki/SipHash
+ * @see https://github.com/veorq/SipHash
+ *
+ * @param key
+ * @param capacity
+ * @return uint64_t
+ * @since v2.0.0
+ */
+uint64_t hash(string_t key, size_t capacity);
+
+/**
+ * @brief Hash map initialization.
+ *
+ * @return struct hash_map*
+ * @since v2.0.0
+ */
+struct hash_map *hash_map_initialization();
+
+/**
+ * @brief Add an item to the hash map.
+ *
+ * @param hash_map
+ * @param key
+ * @param data
+ * @since v2.0.0
+ */
+void hash_map_add(struct hash_map *hash_map, string_t key, void *data);
+
+/**
+ * @brief Remove an item from the hash map.
+ * @param hash_map
+ * @param key
+ * @since v2.0.0
+ */
+void hash_map_remove(struct hash_map *hash_map, string_t key);
+
+/**
+ * @brief Get an item from the hash map.
+ * @param hash_map
+ * @param key
+ * @return void*
+ * @since v2.0.0
+ */
+void *hash_map_get(struct hash_map *hash_map, string_t key);
+
+/**
+ * @brief Check if the hash map contains a key.
+ *
+ * @param hash_map
+ * @param key
+ * @return true
+ * @return false
+ * @since v2.0.0
+ */
+bool hash_map_contains_key(struct hash_map *hash_map, string_t key);
+
+/**
+ * @brief Get the hash map keys.
+ *
+ * @param hash_map
+ * @return string_t*
+ * @since v2.0.0
+ */
+string_t *hash_map_get_keys(struct hash_map *hash_map);
+
+/**
+ * @brief Frees the hash map.
+ *
+ * @param hash_map
+ * @since v3.0.0
+ */
+void hash_map_free(struct hash_map *hash_map);
+
+#endif

lib/linked_list.c

@@ -1,13 +1,9 @@
 #include "linked_list.h"
 
-#include <stdbool.h>
-#include <stdlib.h>
-
-#include "stack.h"
-
 struct linked_list *linked_list_initialization() {
-  struct linked_list *list = malloc(sizeof(*list));
+  struct linked_list *list = malloc(sizeof(struct linked_list));
   if (list == NULL) {
+    perror("Error (linked_list_initialization)");
     exit(EXIT_FAILURE);
   }
   list->head = NULL;
@@ -16,8 +12,14 @@ struct linked_list *linked_list_initialization() {
 }
 
 struct linked_list_node *linked_list_add_in_head(struct linked_list *list, void *new_data) {
-  struct linked_list_node *node_new = malloc(sizeof(*node_new));
+  if (list == NULL) {
-  if (list == NULL || node_new == NULL) {
+    errno = EINVAL;
+    perror("Error (linked_list_add_in_head)");
+    exit(EXIT_FAILURE);
+  }
+  struct linked_list_node *node_new = malloc(sizeof(struct linked_list_node));
+  if (node_new == NULL) {
+    perror("Error (linked_list_add_in_head)");
     exit(EXIT_FAILURE);
   }
   node_new->data = new_data;
@@ -29,6 +31,8 @@ struct linked_list_node *linked_list_add_in_head(struct linked_list *list, void
 
 void linked_list_delete_in_head(struct linked_list *list) {
   if (list == NULL) {
+    errno = EINVAL;
+    perror("Error (linked_list_delete_in_head)");
     exit(EXIT_FAILURE);
   }
   if (list->head != NULL) {
@@ -40,11 +44,17 @@ void linked_list_delete_in_head(struct linked_list *list) {
 }
 
 struct linked_list_node *linked_list_add_after_last(struct linked_list *list, void *new_data) {
+  if (list == NULL) {
+    errno = EINVAL;
+    perror("Error (linked_list_add_after_last)");
+    exit(EXIT_FAILURE);
+  }
   if (list->head == NULL) {
     return linked_list_add_in_head(list, new_data);
   }
-  struct linked_list_node *node_new = malloc(sizeof(*node_new));
+  struct linked_list_node *node_new = malloc(sizeof(struct linked_list_node));
-  if (list == NULL || node_new == NULL) {
+  if (node_new == NULL) {
+    perror("Error (linked_list_add_after_last)");
     exit(EXIT_FAILURE);
   }
   node_new->data = new_data;
@@ -73,6 +83,7 @@ struct linked_list *linked_list_reverse(struct linked_list *list) {
     linked_list_add_after_last(linked_list_reversed, stack_node_current->data);
     stack_node_current = stack_node_current->next;
   }
+  stack_free(stack);
   return linked_list_reversed;
 }
 
@@ -89,3 +100,14 @@ void linked_list_reverse_mutate(struct linked_list *list) {
     (*current) = temporary_current;
   }
 }
+
+void linked_list_free(struct linked_list *list) {
+  struct linked_list_node *node_current = list->head;
+  while (node_current != NULL) {
+    struct linked_list_node *node_to_remove = node_current;
+    node_current = node_current->next;
+    free(node_to_remove);
+  }
+  list->head = NULL;
+  free(list);
+}

lib/linked_list.h

@@ -1,30 +1,90 @@
-#ifndef __LINKED_LIST__
+#ifndef __LIBCPROJECT_LINKED_LIST__
-#define __LINKED_LIST__
+#define __LIBCPROJECT_LINKED_LIST__
 
+#include <errno.h>
+#include <stdbool.h>
 #include <stdlib.h>
 
-struct linked_list {
+#include "stack.h"
-  // first node of the list
+#include "types.h"
-  struct linked_list_node *head;
 
+/**
+ * @brief Linked list data structure.
+ * @since v1.0.0
+ */
+struct linked_list {
+  struct linked_list_node *head;
   size_t length;
 };
 
+/**
+ * @brief Linked list node data structure.
+ * @since v1.0.0
+ */
 struct linked_list_node {
   void *data;
   struct linked_list_node *next;
 };
 
+/**
+ * @brief Linked list initialization.
+ *
+ * @return struct linked_list*
+ * @since v1.0.0
+ */
 struct linked_list *linked_list_initialization();
 
+/**
+ * @brief Add a new node in the head of the linked list.
+ *
+ * @param list
+ * @param new_value
+ * @return struct linked_list_node*
+ * @since v1.0.0
+ */
 struct linked_list_node *linked_list_add_in_head(struct linked_list *list, void *new_value);
 
+/**
+ * @brief Delete node in the head of the linked list.
+ *
+ * @param list
+ * @since v1.0.0
+ */
 void linked_list_delete_in_head(struct linked_list *list);
 
+/**
+ * @brief Add a new node in the tail of the linked list.
+ *
+ * @param list
+ * @param new_data
+ * @return struct linked_list_node*
+ * @since v1.0.0
+ */
 struct linked_list_node *linked_list_add_after_last(struct linked_list *list, void *new_data);
 
+/**
+ * @brief Reverse the linked list by creating a new one.
+ *
+ * @param list
+ * @return struct linked_list*
+ * @since v1.0.0
+ */
 struct linked_list *linked_list_reverse(struct linked_list *list);
 
+/**
+ * @brief Reverse the linked list by mutating it.
+ *
+ * @param list
+ * @since v1.0.0
+ */
 void linked_list_reverse_mutate(struct linked_list *list);
 
+/**
+ * @brief Frees the linked list.
+ *
+ * @param list
+ * @since v3.0.0
+ */
+void linked_list_free(struct linked_list *list);
+
 #endif

lib/mathematics.c

@@ -1,7 +1,5 @@
 #include "mathematics.h"
 
-#include <stdbool.h>
-
 bool mathematics_equals(const float number1, const float number2) {
   return (number1 - number2) < MATHEMATICS_FLOAT_PRECISION;
 }
@@ -34,3 +32,39 @@ float mathematics_square_root(float number) {
 unsigned long long mathematics_factorial(unsigned long long number) {
   return number == 0 ? 1 : number * mathematics_factorial(number - 1);
 }
+
+int64_t mathematics_opposite(int64_t number) {
+  return number * -1;
+}
+
+int64_t mathematics_max(int64_t number1, int64_t number2) {
+  return number1 > number2 ? number1 : number2;
+}
+
+int64_t mathematics_max_values(int64_t *values, size_t values_length) {
+  int64_t max = 0;
+  if (values_length <= 0) {
+    return max;
+  }
+  max = values[0];
+  for (size_t index = 1; index < values_length; index++) {
+    max = mathematics_max(max, values[index]);
+  }
+  return max;
+}
+
+int64_t mathematics_min(int64_t number1, int64_t number2) {
+  return number1 > number2 ? number2 : number1;
+}
+
+int64_t mathematics_min_values(int64_t *values, size_t values_length) {
+  int64_t min = 0;
+  if (values_length <= 0) {
+    return min;
+  }
+  min = values[0];
+  for (size_t index = 1; index < values_length; index++) {
+    min = mathematics_min(min, values[index]);
+  }
+  return min;
+}

lib/mathematics.h

@@ -1,27 +1,125 @@
-#ifndef __MATHEMATICS__
+#ifndef __LIBCPROJECT_MATHEMATICS__
-#define __MATHEMATICS__
+#define __LIBCPROJECT_MATHEMATICS__
 
 #define MATHEMATICS_FLOAT_PRECISION 0.00000001
 
+#include <errno.h>
 #include <stdbool.h>
+#include <stdlib.h>
 
+#include "types.h"
+
+/**
+ * @brief Verify that 2 numbers are equal.
+ *
+ * @param number1
+ * @param number2
+ * @return true
+ * @return false
+ * @since v1.0.0
+ */
 bool mathematics_equals(const float number1, const float number2);
 
+/**
+ * @brief Get the absolute value of a number.
+ *
+ * @param number
+ * @return unsigned long long
+ * @since v1.0.0
+ */
 unsigned long long mathematics_absolute_value(const long long number);
 
+/**
+ * @brief Calculates the power of a number.
+ *
+ * @param base
+ * @param exponent
+ * @return unsigned long long
+ * @since v1.0.0
+ */
 unsigned long long mathematics_pow(unsigned long long base, unsigned long long exponent);
 
 /**
- * @brief Calculates the nth root of a number using Heron's method.
+ * @brief Calculates the nth root of a number.
  *
  * @param number
  * @param nth_root
  * @return float
+ * @since v1.0.0
  */
 float mathematics_root(float number, unsigned int nth_root);
 
+/**
+ * @brief Calculates the square root of a number using Heron's method.
+ *
+ * @param number
+ * @return float
+ * @since v1.0.0
+ */
 float mathematics_square_root(float number);
 
+/**
+ * @brief Calculates the factorial of a number.
+ *
+ * @param number
+ * @return unsigned long long
+ * @since v1.0.0
+ */
 unsigned long long mathematics_factorial(unsigned long long number);
 
+/**
+ * @brief Calulcates the opposite number (additive inverse).
+ *
+ * @param number
+ * @return int64_t
+ *
+ * @code
+ * mathematics_opposite(7) // -7
+ *
+ * mathematics_opposite(-7) // 7
+ * @endcode
+ * @since v4.3.0
+ */
+int64_t mathematics_opposite(int64_t number);
+
+/**
+ * @brief Returns the largest number between 2 numbers.
+ *
+ * @param number1
+ * @param number2
+ * @return int64_t
+ * @since v4.3.0
+ */
+int64_t mathematics_max(int64_t number1, int64_t number2);
+
+/**
+ * @brief Returns the largest number between multiple numbers. If the array is empty, returns 0.
+ *
+ * @param values
+ * @param values_length
+ * @return int64_t
+ * @since v4.3.0
+ */
+int64_t mathematics_max_values(int64_t *values, size_t values_length);
+
+/**
+ * @brief Returns the smallest number between 2 numbers.
+ *
+ * @param number1
+ * @param number2
+ * @return int64_t
+ * @since v4.3.0
+ */
+int64_t mathematics_min(int64_t number1, int64_t number2);
+
+/**
+ * @brief Returns the smallest number between multiple numbers. If the array is empty, returns 0.
+ *
+ * @param values
+ * @param values_length
+ * @return int64_t
+ * @since v4.3.0
+ */
+int64_t mathematics_min_values(int64_t *values, size_t values_length);
+
 #endif

lib/queue.c

@@ -1,11 +1,9 @@
 #include "queue.h"
 
-#include <stdio.h>
-#include <stdlib.h>
-
 struct queue *queue_initialization() {
-  struct queue *queue = malloc(sizeof(*queue));
+  struct queue *queue = malloc(sizeof(struct queue));
   if (queue == NULL) {
+    perror("Error (queue_initialization)");
     exit(EXIT_FAILURE);
   }
   queue->first = NULL;
@@ -14,8 +12,14 @@ struct queue *queue_initialization() {
 }
 
 void queue_push(struct queue *queue, void *data) {
-  struct queue_node *node_new = malloc(sizeof(*node_new));
+  if (queue == NULL) {
-  if (queue == NULL || node_new == NULL) {
+    errno = EINVAL;
+    perror("Error (queue_push)");
+    exit(EXIT_FAILURE);
+  }
+  struct queue_node *node_new = malloc(sizeof(struct queue_node));
+  if (node_new == NULL) {
+    perror("Error (queue_push)");
     exit(EXIT_FAILURE);
   }
   node_new->data = data;
@@ -34,6 +38,8 @@ void queue_push(struct queue *queue, void *data) {
 
 void *queue_pop(struct queue *queue) {
   if (queue == NULL) {
+    errno = EINVAL;
+    perror("Error (queue_pop)");
     exit(EXIT_FAILURE);
   }
   struct queue_node *node = queue->first;
@@ -46,3 +52,18 @@ void *queue_pop(struct queue *queue) {
   queue->length = queue->length - 1;
   return data;
 }
+
+void queue_free(struct queue *queue) {
+  if (queue == NULL) {
+    errno = EINVAL;
+    perror("Error (queue_free)");
+    exit(EXIT_FAILURE);
+  }
+  struct queue_node *node = queue->first;
+  while (node != NULL) {
+    struct queue_node *node_next = node->next;
+    free(node);
+    node = node_next;
+  }
+  free(queue);
+}

lib/queue.h

@@ -1,23 +1,62 @@
-#ifndef __QUEUE__
+#ifndef __LIBCPROJECT_QUEUE__
-#define __QUEUE__
+#define __LIBCPROJECT_QUEUE__
 
+#include <errno.h>
+#include <stdio.h>
 #include <stdlib.h>
 
-// FIFO = First In First Out
+#include "types.h"
+
+/**
+ * @brief Queue structure => FIFO (First In First Out).
+ * @since v1.0.0
+ */
 struct queue {
   struct queue_node *first;
   size_t length;
 };
 
+/**
+ * @brief Queue node structure.
+ * @since v1.0.0
+ */
 struct queue_node {
   void *data;
   struct queue_node *next;
 };
 
+/**
+ * @brief Queue initialization.
+ *
+ * @return struct queue*
+ * @since v1.0.0
+ */
 struct queue *queue_initialization();
 
+/**
+ * @brief Push data to queue.
+ *
+ * @param queue
+ * @param data
+ * @since v1.0.0
+ */
 void queue_push(struct queue *queue, void *data);
 
+/**
+ * @brief Pop data from queue.
+ *
+ * @param queue
+ * @return void*
+ * @since v1.0.0
+ */
 void *queue_pop(struct queue *queue);
 
+/**
+ * @brief Frees the queue.
+ *
+ * @param queue
+ * @since v3.0.0
+ */
+void queue_free(struct queue *queue);
+
 #endif

lib/stack.c

@@ -1,11 +1,9 @@
 #include "stack.h"
 
-#include <stdio.h>
-#include <stdlib.h>
-
 struct stack *stack_initialization() {
-  struct stack *stack = malloc(sizeof(*stack));
+  struct stack *stack = malloc(sizeof(struct stack));
   if (stack == NULL) {
+    perror("Error (stack_initialization)");
     exit(EXIT_FAILURE);
   }
   stack->first = NULL;
@@ -14,8 +12,14 @@ struct stack *stack_initialization() {
 }
 
 void stack_push(struct stack *stack, void *data) {
-  struct stack_node *node_new = malloc(sizeof(*node_new));
+  if (stack == NULL) {
-  if (stack == NULL || data == NULL) {
+    errno = EINVAL;
+    perror("Error (stack_push)");
+    exit(EXIT_FAILURE);
+  }
+  struct stack_node *node_new = malloc(sizeof(struct stack_node));
+  if (data == NULL) {
+    perror("Error (stack_push)");
     exit(EXIT_FAILURE);
   }
   node_new->data = data;
@@ -26,6 +30,8 @@ void stack_push(struct stack *stack, void *data) {
 
 void *stack_pop(struct stack *stack) {
   if (stack == NULL) {
+    errno = EINVAL;
+    perror("Error (stack_pop)");
     exit(EXIT_FAILURE);
   }
   struct stack_node *node = stack->first;
@@ -38,3 +44,18 @@ void *stack_pop(struct stack *stack) {
   stack->length = stack->length - 1;
   return data;
 }
+
+void stack_free(struct stack *stack) {
+  if (stack == NULL) {
+    errno = EINVAL;
+    perror("Error (stack_free)");
+    exit(EXIT_FAILURE);
+  }
+  struct stack_node *node = stack->first;
+  while (node != NULL) {
+    struct stack_node *node_next = node->next;
+    free(node);
+    node = node_next;
+  }
+  free(stack);
+}

lib/stack.h

@@ -1,23 +1,62 @@
-#ifndef __STACK__
+#ifndef __LIBCPROJECT_STACK__
-#define __STACK__
+#define __LIBCPROJECT_STACK__
 
+#include <errno.h>
+#include <stdio.h>
 #include <stdlib.h>
 
-// LIFO = Last In First Out
+#include "types.h"
+
+/**
+ * @brief Stack structure => LIFO (Last In First Out).
+ * @since v1.0.0
+ */
 struct stack {
   struct stack_node *first;
   size_t length;
 };
 
+/**
+ * @brief Stack node structure.
+ * @since v1.0.0
+ */
 struct stack_node {
   void *data;
   struct stack_node *next;
 };
 
+/**
+ * @brief Stack initialization.
+ *
+ * @return struct stack*
+ * @since v1.0.0
+ */
 struct stack *stack_initialization();
 
+/**
+ * @brief Push data to stack.
+ *
+ * @param stack
+ * @param data
+ * @since v1.0.0
+ */
 void stack_push(struct stack *stack, void *data);
 
+/**
+ * @brief Pop data from stack.
+ *
+ * @param stack
+ * @return void*
+ * @since v1.0.0
+ */
 void *stack_pop(struct stack *stack);
 
+/**
+ * @brief Frees the stack.
+ *
+ * @param stack
+ * @since v3.0.0
+ */
+void stack_free(struct stack *stack);
+
 #endif

lib/string.c

@@ -1,14 +1,6 @@
 #include "string.h"
 
-#include <stdbool.h>
+size_t string_get_length(const string_t string) {
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "character.h"
-#include "convert.h"
-#include "dictionary.h"
-
-size_t string_get_length(const char* string) {
   size_t length = 0;
   while (string[length] != '\0') {
     length++;
@@ -16,107 +8,99 @@ size_t string_get_length(const char* string) {
   return length;
 }
 
-char* string_to_uppercase(char* string) {
+void string_to_uppercase(string_t string) {
   size_t string_length = string_get_length(string);
-  char* result = malloc(sizeof(char*) * string_length);
-  if (result == NULL) {
-    exit(EXIT_FAILURE);
-  }
   for (size_t index = 0; index < string_length; index++) {
-    character_append(result, character_to_upper(string[index]));
+    string[index] = character_to_upper(string[index]);
   }
-  return result;
+  string[string_length] = '\0';
 }
 
-char* string_to_lowercase(char* string) {
+void string_to_lowercase(string_t string) {
   size_t string_length = string_get_length(string);
-  char* result = malloc(sizeof(char*) * string_length);
-  if (result == NULL) {
-    exit(EXIT_FAILURE);
-  }
   for (size_t index = 0; index < string_length; index++) {
-    character_append(result, character_to_lower(string[index]));
+    string[index] = character_to_lower(string[index]);
   }
-  return result;
+  string[string_length] = '\0';
 }
 
-char* string_replace(char* string, char search, char replace) {
+void string_replace(string_t string, char search, char replace) {
   size_t string_length = string_get_length(string);
-  char* result = malloc(sizeof(char*) * string_length);
-  if (result == NULL) {
-    exit(EXIT_FAILURE);
-  }
   for (size_t index = 0; index < string_length; index++) {
     bool is_search_value = search == string[index];
     if (is_search_value) {
-      character_append(result, replace);
+      string[index] = replace;
     } else {
-      character_append(result, string[index]);
+      string[index] = string[index];
     }
   }
-  return result;
+  string[string_length] = '\0';
 }
 
-char* string_trim_start(char* string) {
+void string_remove_character(string_t string, char search) {
   size_t string_length = string_get_length(string);
-  char* result = malloc(sizeof(char*) * string_length);
+  for (size_t index = 0; index < string_length; index++) {
-  if (result == NULL) {
+    if (string[index] == search) {
-    exit(EXIT_FAILURE);
+      for (size_t index_string = index; index_string < string_length; index_string++) {
+        string[index_string] = string[index_string + 1];
       }
+      string_length--;
+      index--;
+    }
+  }
+  string[string_length] = '\0';
+}
+
+void string_trim_start(string_t string, char character) {
+  size_t string_length = string_get_length(string);
   size_t index_space = 0;
-  while (string[index_space] == ' ') {
+  while (string[index_space] == character) {
     index_space++;
   }
-  for (size_t index = index_space; index < string_length; index++) {
+  for (size_t index = 0; index < string_length - index_space; index++) {
-    character_append(result, string[index]);
+    string[index] = string[index + index_space];
   }
-  return result;
+  string[string_length - index_space] = '\0';
 }
 
-char* string_trim_end(char* string) {
+void string_trim_end(string_t string, char character) {
   size_t string_length = string_get_length(string);
-  char* result = malloc(sizeof(char*) * string_length);
-  if (result == NULL) {
-    exit(EXIT_FAILURE);
-  }
   size_t index_space = string_length - 1;
-  while (string[index_space] == ' ') {
+  while (string[index_space] == character) {
     index_space--;
   }
-  for (size_t index = 0; index < index_space + 1; index++) {
+  string[index_space + 1] = '\0';
-    character_append(result, string[index]);
-  }
-  return result;
 }
 
-char* string_trim(char* string) {
+void string_trim(string_t string, char character) {
-  char* result = string_trim_start(string);
+  string_trim_start(string, character);
-  result = string_trim_end(result);
+  string_trim_end(string, character);
-  return result;
 }
 
-char* string_copy(const char* string) {
+string_t string_copy(const string_t string) {
-  return string_substring(string, 0, string_get_length(string));
+  size_t source_length = string_get_length(string);
-}
+  string_t copy = malloc(sizeof(char) * (source_length + 1));
-
+  if (copy == NULL) {
-char* string_capitalize(char* string) {
+    perror("Error (string_copy)");
-  size_t string_length = string_get_length(string);
-  char* result = malloc(sizeof(char*) * string_length);
-  if (result == NULL) {
     exit(EXIT_FAILURE);
   }
-  for (size_t index = 0; index < string_length; index++) {
+  size_t index;
-    bool is_first_character = index == 0;
+  for (index = 0; index < source_length; index++) {
-    if (is_first_character) {
+    copy[index] = string[index];
-      character_append(result, character_to_upper(string[index]));
-    } else {
-      character_append(result, string[index]);
   }
-  }
+  copy[index] = '\0';
-  return result;
+  return copy;
 }
 
-size_t string_total_occurrences_of_character(char* string, char character) {
+void string_capitalize(string_t string) {
+  size_t string_length = string_get_length(string);
+  if (string_length == 0) {
+    return;
+  }
+  string[0] = character_to_upper(string[0]);
+}
+
+size_t string_total_occurrences_of_character(string_t string, char character) {
   size_t result = 0;
   size_t string_length = string_get_length(string);
   for (size_t index = 0; index < string_length; index++) {
@@ -128,21 +112,20 @@ size_t string_total_occurrences_of_character(char* string, char character) {
   return result;
 }
 
-char* string_reverse(const char* string) {
+void string_reverse(const string_t string) {
   size_t string_length = string_get_length(string);
-  size_t index = 0;
+  size_t index_start = 0;
-  char* result = malloc(sizeof(char*) * string_length);
+  size_t index_end = string_length - 1;
-  if (result == NULL) {
+  while (index_start < index_end) {
-    exit(EXIT_FAILURE);
+    char temporary = string[index_start];
+    string[index_start] = string[index_end];
+    string[index_end] = temporary;
+    index_start++;
+    index_end--;
   }
-  for (index = string_length - 1; index > 0; index--) {
-    character_append(result, string[index]);
-  }
-  character_append(result, string[index]);
-  return result;
 }
 
-bool string_equals(const char* string1, const char* string2) {
+bool string_equals(const string_t string1, const string_t string2) {
   size_t string1_length = string_get_length(string1);
   size_t string2_length = string_get_length(string2);
   bool is_equal = string1_length == string2_length;
@@ -154,7 +137,7 @@ bool string_equals(const char* string1, const char* string2) {
   return is_equal;
 }
 
-bool string_get_is_integer(const char* string) {
+bool string_get_is_integer(const string_t string) {
   size_t index = 0;
   size_t string_length = string_get_length(string);
   bool is_integer = string_length >= 1;
@@ -174,106 +157,130 @@ bool string_get_is_integer(const char* string) {
   return is_integer;
 }
 
-char** string_split(const char* string, char separator, size_t* result_size) {
+string_t* string_split(const string_t string, char separator, size_t* result_size) {
   size_t string_length = string_get_length(string);
   size_t index_string = 0;
   size_t index_current = 0;
   size_t index_result = 0;
-  char* current = malloc(sizeof(char*) * string_length);
+  string_t current = malloc(sizeof(char) * (string_length + 1));
-  char** result = malloc(sizeof(char**) * index_result);
+  string_t* result = NULL;
-  if (result == NULL || current == NULL) {
+  if (current == NULL) {
+    perror("Error (string_split)");
     exit(EXIT_FAILURE);
   }
   while (index_string < string_length) {
     if (string[index_string] == separator) {
-      result[index_result] = string_copy(current);
+      current[index_current] = '\0';
-      index_result++;
+      result = realloc(result, sizeof(string_t) * (index_result + 1));
-      result = realloc(result, sizeof(char*) * index_result);
       if (result == NULL) {
+        perror("Error (string_split)");
         exit(EXIT_FAILURE);
       }
+      result[index_result] = string_copy(current);
+      index_result++;
       index_current = 0;
-      current = string_copy("");
     } else {
-      character_append(current, string[index_string]);
+      current[index_current] = string[index_string];
       index_current++;
     }
     index_string++;
   }
+  current[index_current] = '\0';
+  result = realloc(result, sizeof(string_t) * (index_result + 1));
+  if (result == NULL) {
+    perror("Error (string_split)");
+    exit(EXIT_FAILURE);
+  }
   result[index_result] = string_copy(current);
   free(current);
   *result_size = index_result + 1;
   return result;
 }
 
-char* string_join(char** array, const char separator, size_t array_length) {
+string_t string_join(string_t* array, const char separator, size_t array_length) {
-  size_t string_length = array_length;
+  size_t total_length = 0;
-  char* string = malloc(sizeof(char*) * string_length);
-  if (string == NULL) {
-    exit(EXIT_FAILURE);
-  }
   for (size_t index_array = 0; index_array < array_length; index_array++) {
-    char* substring = array[index_array];
+    total_length += string_get_length(array[index_array]);
-    size_t substring_length = string_get_length(substring);
+  }
-    string_length += substring_length;
+  size_t string_length = total_length + (array_length - 1);
-    string = realloc(string, sizeof(char*) * string_length);
+  string_t string = malloc(sizeof(char) * (string_length + 1));
   if (string == NULL) {
+    perror("Error (string_join)");
     exit(EXIT_FAILURE);
   }
+  size_t current_index = 0;
+  for (size_t index_array = 0; index_array < array_length; index_array++) {
+    string_t substring = array[index_array];
+    size_t substring_length = string_get_length(substring);
     for (size_t index_substring = 0; index_substring < substring_length; index_substring++) {
-      character_append(string, substring[index_substring]);
+      string[current_index] = substring[index_substring];
+      current_index++;
     }
     bool is_last_character = index_array == (array_length - 1);
     if (!is_last_character) {
-      character_append(string, separator);
+      string[current_index] = separator;
+      current_index++;
     }
   }
+  string[string_length] = '\0';
   return string;
 }
 
-char* string_concatenate(char* string1, char* string2) {
+void string_concatenate(string_t* destination, string_t source) {
-  size_t string1_length = string_get_length(string1);
+  size_t destination_length = string_get_length(*destination);
-  size_t string2_length = string_get_length(string2);
+  size_t source_length = string_get_length(source);
-  size_t result_length = string1_length + string2_length;
+  size_t new_length = destination_length + source_length;
-  char* result = malloc(sizeof(char*) * result_length);
+  *destination = realloc(*destination, sizeof(char) * (new_length + 1));
-  if (result == NULL) {
+  if (*destination == NULL) {
+    perror("Error (string_concatenate)");
     exit(EXIT_FAILURE);
   }
-  for (size_t index_string1 = 0; index_string1 < string1_length; index_string1++) {
+  size_t index_destination = destination_length;
-    character_append(result, string1[index_string1]);
+  for (size_t index_source = 0; index_source < source_length; index_source++) {
+    (*destination)[index_destination++] = source[index_source];
   }
-  for (size_t index_string2 = 0; index_string2 < string2_length; index_string2++) {
+  (*destination)[index_destination] = '\0';
-    character_append(result, string2[index_string2]);
-  }
-  return result;
 }
 
-bool string_get_has_unique_characters(const char* string) {
+bool string_get_has_unique_characters(const string_t string) {
   bool has_unique = true;
   size_t string_length = string_get_length(string);
-  struct dictionary* characters_already_seen = dictionary_initialization();
+  struct hash_map* characters_already_seen = hash_map_initialization();
+  string_t* keys = malloc(sizeof(string_t) * string_length);
+  for (size_t index = 0; index < string_length; index++) {
+    keys[index] = NULL;
+  }
   for (size_t index = 0; index < string_length && has_unique; index++) {
     char character = string[index];
-    char* key = convert_character_to_string(character);
+    keys[index] = convert_character_to_string(character);
-    if (dictionary_contains_key(characters_already_seen, key)) {
+    string_t key = keys[index];
+    if (hash_map_contains_key(characters_already_seen, key)) {
       has_unique = false;
     } else {
-      dictionary_add(characters_already_seen, key, (void*)true);
+      hash_map_add(characters_already_seen, key, (void*)true);
     }
   }
+  for (size_t index = 0; index < string_length; index++) {
+    if (keys[index] != NULL) {
+      free(keys[index]);
+    }
+  }
+  free(keys);
+  hash_map_free(characters_already_seen);
   return has_unique;
 }
 
-char* string_substring(const char* string, size_t index_start, size_t index_end) {
+string_t string_substring(const string_t string, size_t index_start, size_t index_end) {
-  size_t string_length = string_get_length(string);
+  size_t substring_length = index_end - index_start + 1;
-  char* result = malloc(sizeof(char*) * string_length);
+  string_t result = malloc(sizeof(char) * (substring_length + 1));
-  for (size_t index = index_start; index <= index_end; index++) {
+  for (size_t index = 0; index < substring_length; index++) {
-    character_append(result, string[index]);
+    result[index] = string[index_start + index];
   }
+  result[substring_length] = '\0';
   return result;
 }
 
-bool string_get_is_substring(const char* string, const char* substring) {
+bool string_get_is_substring(const string_t string, const string_t substring) {
   bool is_substring = false;
   size_t string_length = string_get_length(string);
   size_t substring_length = string_get_length(substring);
@@ -289,57 +296,73 @@ bool string_get_is_substring(const char* string, const char* substring) {
   return is_substring;
 }
 
-char* string_get_formatted_number(const long long number, char* separator) {
+string_t string_get_formatted_number(const long long number, string_t separator) {
-  char* number_string = convert_number_to_string(number);
+  string_t number_string_temp = convert_number_to_string(number);
-  bool is_negative = number_string[0] == '-';
+  string_t number_string = number_string_temp;
+  bool is_negative = number_string_temp[0] == '-';
   if (is_negative) {
-    number_string = string_substring(number_string, 1, string_get_length(number_string));
+    number_string = string_substring(number_string_temp, 1, string_get_length(number_string_temp));
+    free(number_string_temp);
   }
   size_t number_string_length = string_get_length(number_string);
-  char* result = malloc(sizeof(char*) * number_string_length);
+  size_t formatted_length = number_string_length + (number_string_length - 1) / 3;
+  string_t result = malloc(sizeof(char) * (formatted_length + 1));
   if (result == NULL) {
+    perror("Error (string_get_formatted_number)");
     exit(EXIT_FAILURE);
   }
   size_t count = 0;
+  size_t result_index = 0;
   for (size_t index = 0; index < number_string_length; index++) {
     size_t index_reversed = number_string_length - index - 1;
+    result[result_index] = number_string[index_reversed];
     count++;
-    result = string_concatenate(result, convert_character_to_string(number_string[index_reversed]));
+    result_index++;
-    if (count == 3) {
+    if (count == 3 && index != number_string_length - 1) {
-      result = string_concatenate(result, separator);
+      for (size_t sep_index = 0; sep_index < string_get_length(separator); sep_index++) {
+        result[result_index] = separator[sep_index];
+        result_index++;
+      }
       count = 0;
     }
   }
-  result = string_reverse(result);
+  free(number_string);
-  size_t result_length = string_get_length(result);
+  result[formatted_length] = '\0';
-  if (result_length % 4 == 0) {
+  string_reverse(result);
-    result = string_substring(result, 1, result_length);
-  }
   if (is_negative) {
-    result = string_concatenate(convert_character_to_string('-'), result);
+    string_t negative_result = convert_character_to_string('-');
+    string_concatenate(&negative_result, result);
+    free(result);
+    return negative_result;
   }
   return result;
 }
 
-char* string_get_last_occurence_of_character(const char* string, char character) {
+string_t string_get_last_occurence_of_character(const string_t string, char character) {
   size_t string_length = string_get_length(string);
-  char* result = malloc(sizeof(char*) * string_length);
+  size_t index_last_occurrence = SIZE_MAX;
+  for (size_t index = 0; index < string_length; index++) {
+    if (string[index] == character) {
+      index_last_occurrence = index;
+    }
+  }
+  if (index_last_occurrence == SIZE_MAX) {
+    return "";
+  }
+  string_t result = malloc(sizeof(char) * (string_length - index_last_occurrence + 1));
   if (result == NULL) {
+    perror("Error (string_get_last_occurence_of_character)");
     exit(EXIT_FAILURE);
   }
   size_t index_result = 0;
-  for (size_t index = 0; index < string_length; index++) {
+  for (size_t index = index_last_occurrence; index < string_length; index++) {
-    if (string[index] == character) {
+    result[index_result++] = string[index];
-      index_result = 0;
-      result = string_copy("");
-    }
-    character_append(result, string[index]);
-    index_result++;
   }
+  result[index_result] = '\0';
   return result;
 }
 
-bool string_starts_with(const char* string, const char* prefix) {
+bool string_starts_with(const string_t string, const string_t prefix) {
   bool starts_with = true;
   size_t prefix_length = string_get_length(prefix);
   for (size_t index = 0; index < prefix_length && starts_with; index++) {
@@ -348,7 +371,7 @@ bool string_starts_with(const char* string, const char* prefix) {
   return starts_with;
 }
 
-bool string_ends_with(const char* string, const char* prefix) {
+bool string_ends_with(const string_t string, const string_t prefix) {
   bool ends_with = true;
   size_t string_length = string_get_length(string);
   size_t prefix_length = string_get_length(prefix);
@@ -361,3 +384,59 @@ bool string_ends_with(const char* string, const char* prefix) {
   }
   return ends_with;
 }
+
+size_t string_position_of(const string_t string, const char character) {
+  size_t position_found = 0;
+  size_t string_length = string_get_length(string);
+  for (size_t index = 0; index < string_length && position_found == 0; index++) {
+    if (string[index] == character) {
+      position_found = index + 1;
+    }
+  }
+  return position_found;
+}
+
+size_t string_last_position_of(const string_t string, const char character) {
+  size_t position_found = 0;
+  size_t string_length = string_get_length(string);
+  while (string_length > 0 && position_found == 0) {
+    if (string[string_length - 1] == character) {
+      position_found = string_length;
+    }
+    string_length--;
+  }
+  return position_found;
+}
+
+string_t string_pad_start(const string_t string, const string_t pad_string, size_t target_length) {
+  string_t result = malloc(sizeof(char) * (target_length + 1));
+  size_t initial_length = string_get_length(string);
+  size_t left_length = target_length - initial_length;
+  if (target_length <= initial_length) {
+    left_length = 0;
+  }
+  size_t pad_length = string_get_length(pad_string);
+  size_t count_pad_string = 0;
+  size_t index_initial_string = 0;
+  for (size_t index = 0; index < target_length; index++) {
+    if (index < left_length) {
+      size_t index_pad_string = count_pad_string % pad_length;
+      result[index] = pad_string[index_pad_string];
+      count_pad_string += 1;
+    } else {
+      result[index] = string[index_initial_string];
+      index_initial_string += 1;
+    }
+  }
+  result[target_length] = '\0';
+  return result;
+}
+
+string_t string_zero_pad(uint64_t number, size_t places) {
+  string_t number_string = convert_number_to_string((long long)number);
+  string_t pad_string = string_copy("0");
+  string_t result = string_pad_start(number_string, pad_string, places);
+  free(pad_string);
+  free(number_string);
+  return result;
+}

lib/string.h

@@ -1,82 +1,116 @@
-#ifndef __STRING__
+#ifndef __LIBCPROJECT_STRING__
-#define __STRING__
+#define __LIBCPROJECT_STRING__
 
+#include <errno.h>
 #include <stdbool.h>
+#include <stdio.h>
 #include <stdlib.h>
 
+#include "character.h"
+#include "convert.h"
+#include "hash_map.h"
+#include "types.h"
+
 /**
  * @brief Return the length of a string (excluding '\0').
  *
  * @param string
  * @return size_t
+ * @since v1.0.0
  */
-size_t string_get_length(const char* string);
+size_t string_get_length(const string_t string);
 
 /**
  * @brief Converts all the alphabetic characters in a string to uppercase.
  *
+ * NOTE: Mutates the string.
+ *
  * @param string
- * @return char*
+ * @since v1.0.0
  */
-char* string_to_uppercase(char* string);
+void string_to_uppercase(string_t string);
 
 /**
  * @brief Converts all the alphabetic characters in a string to lowercase.
  *
+ * NOTE: Mutates the string.
+ *
  * @param string
- * @return char*
+ * @since v1.0.0
  */
-char* string_to_lowercase(char* string);
+void string_to_lowercase(string_t string);
 
 /**
  * @brief Replace all the occurrences of search value into replace value in the string.
  *
- * @param string
+ * NOTE: Mutates the string.
- * @param search_value A character search value.
- * @param replace_value A character containing the text to replace for match.
- * @return char*
- */
-char* string_replace(char* string, char search, char replace);
-
-/**
- * @brief Removes all whitespace from the start of a string.
  *
  * @param string
- * @return char*
+ * @param search A character search value.
+ * @param replace A character containing the text to replace for match.
+ * @since v1.0.0
  */
-char* string_trim_start(char* string);
+void string_replace(string_t string, char search, char replace);
 
 /**
- * @brief Removes all whitespace from the end of a string.
+ * @brief Removes all the occurrences of a character in a string.
+ *
+ * NOTE: Mutates the string.
  *
  * @param string
- * @return char*
+ * @param search A character search value.
+ * @since v4.1.0
  */
-char* string_trim_end(char* string);
+void string_remove_character(string_t string, char search);
 
 /**
- * @brief Removes all whitespace from the start and end of a string.
+ * @brief Removes all `character` from the start of a string.
+ *
+ * NOTE: Mutates the string.
  *
  * @param string
- * @return char*
+ * @since v1.0.0
  */
-char* string_trim(char* string);
+void string_trim_start(string_t string, char character);
+
+/**
+ * @brief Removes all `character` from the end of a string.
+ *
+ * NOTE: Mutates the string.
+ *
+ * @param string
+ * @since v1.0.0
+ */
+void string_trim_end(string_t string, char character);
+
+/**
+ * @brief Removes all `character` from the start and end of a string.
+ *
+ * NOTE: Mutates the string.
+ *
+ * @param string
+ * @since v1.0.0
+ */
+void string_trim(string_t string, char character);
 
 /**
  * @brief Return the copy of a string.
  *
  * @param string
- * @return char*
+ * @return string_t
+ * @since v1.0.0
  */
-char* string_copy(const char* string);
+string_t string_copy(const string_t string);
 
 /**
  * @brief Capitalizes the string.
  *
+ * NOTE: Mutates the string.
+ *
  * @param string
- * @return char*
+ * @since v1.0.0
  */
-char* string_capitalize(char* string);
+void string_capitalize(string_t string);
 
 /**
  * @brief Returns the total number of occurrences of the given character in the string.
@@ -84,68 +118,83 @@ char* string_capitalize(char* string);
  * @param string
  * @param character
  * @return size_t
+ * @since v1.0.0
  */
-size_t string_total_occurrences_of_character(char* string, char character);
+size_t string_total_occurrences_of_character(string_t string, char character);
 
 /**
- * @brief Reverse the characters in an array.
+ * @brief Reverse the characters in a string.
+ *
+ * NOTE: Mutates the string.
  *
  * @param string
- * @return char*
+ * @since v1.0.0
  */
-char* string_reverse(const char* string);
+void string_reverse(const string_t string);
 
 /**
  * @brief Check if two strings are equals.
  *
  * @param string1
  * @param string2
- * @return true if the strings are equals, false otherwise
+ * @return true if the strings are equals.
+ * @return false if the strings are not equals.
+ * @since v1.0.0
  */
-bool string_equals(const char* string1, const char* string2);
+bool string_equals(const string_t string1, const string_t string2);
 
 /**
- * @brief Check if the string is a integer.
+ * @brief Check if the string is an integer.
  *
  * @param string
- * @return true if the string is a integer, false otherwise
+ * @return true if the string is an integer.
+ * @return false if the string is not an integer.
+ * @since v1.0.0
  */
-bool string_get_is_integer(const char* string);
+bool string_get_is_integer(const string_t string);
 
 /**
  * @brief Split a string into substrings using the specified separator and return them as an array and update the pointer `result_size` to the resulting size of the created array.
  *
  * @param string
  * @param separator
- * @return char**
+ * @param result_size
+ * @return string_t*
+ * @since v1.0.0
  */
-char** string_split(const char* string, char separator, size_t* result_size);
+string_t* string_split(const string_t string, char separator, size_t* result_size);
 
 /**
  * @brief Adds all the elements of an array into a string, separated by the specified separator string.
  *
  * @param array
  * @param separator
- * @return char*
+ * @param array_length
+ * @return string_t
+ * @since v1.0.0
  */
-char* string_join(char** array, const char separator, size_t array_length);
+string_t string_join(string_t* array, const char separator, size_t array_length);
 
 /**
  * @brief Concatenate two strings.
  *
- * @param string1
+ * NOTE: Mutates the string `destination`.
- * @param string2
+ *
- * @return char*
+ * @param destination
+ * @param source
+ * @since v1.0.0
  */
-char* string_concatenate(char* string1, char* string2);
+void string_concatenate(string_t* destination, string_t source);
 
 /**
  * @brief Check if a string contains only unique characters.
  *
  * @param string
- * @return true if string contains only unique characters, false otherwise
+ * @return true if string contains only unique characters.
+ * @return false if string contains duplicate characters.
+ * @since v1.0.0
  */
-bool string_get_has_unique_characters(const char* string);
+bool string_get_has_unique_characters(const string_t string);
 
 /**
  * @brief Returns the part of the string between the start and end indexes (both included).
@@ -153,52 +202,127 @@ bool string_get_has_unique_characters(const char* string);
  * @param string
  * @param index_start
  * @param index_end
- * @return char*
+ * @return string_t
+ * @since v1.0.0
  */
-char* string_substring(const char* string, size_t index_start, size_t index_end);
+string_t string_substring(const string_t string, size_t index_start, size_t index_end);
 
 /**
  * @brief Check if a string contains a substring.
  *
  * @param string
  * @param substring
- * @return true if the string contains the substring, false otherwise
+ * @return true if the string contains the substring.
+ * @return false if the string does not contain the substring.
+ * @since v1.0.0
  */
-bool string_get_is_substring(const char* string, const char* substring);
+bool string_get_is_substring(const string_t string, const string_t substring);
 
 /**
  * @brief Format a number to a string with specified separator.
  *
- * @param integer
+ * @param number
- * @return char* example: string_get_formatted_number(1000, " ") => "1 000"
+ * @param separator
+ * @return string_t
+ *
+ * @code
+ * string_get_formatted_number(1000, " ") // "1 000"
+ *
+ * string_get_formatted_number(1000, ",") // "1,000"
+ * @endcode
+ * @since v1.0.0
  */
-char* string_get_formatted_number(const long long number, char* separator);
+string_t string_get_formatted_number(const long long number, string_t separator);
 
 /**
  * @brief Returns a pointer to the last occurrence of character in the string.
  *
  * @param string
  * @param character
- * @return char*
+ * @return string_t
+ * @since v1.0.0
  */
-char* string_get_last_occurence_of_character(const char* string, char character);
+string_t string_get_last_occurence_of_character(const string_t string, char character);
 
 /**
  * @brief Check if a string starts with a substring.
  *
  * @param string
  * @param prefix
- * @return true if the string starts with the substring, false otherwise
+ * @return true if the string starts with the substring.
+ * @return false if the string does not start with the substring.
+ * @since v1.0.0
  */
-bool string_starts_with(const char* string, const char* prefix);
+bool string_starts_with(const string_t string, const string_t prefix);
 
 /**
  * @brief Check if a string ends with a substring.
  *
  * @param string
  * @param prefix
- * @return true if the string ends with the substring, false otherwise
+ * @return true if the string ends with the substring.
+ * @return false if the string does not end with the substring.
+ * @since v1.0.0
  */
-bool string_ends_with(const char* string, const char* prefix);
+bool string_ends_with(const string_t string, const string_t prefix);
+
+/**
+ * @brief Returns the position (index + 1) within the string of the first occurrence of the specified substring (0 if not found).
+ *
+ * @param string
+ * @param substring
+ * @return size_t
+ *
+ * @code
+ * string_position_of("hello world", 'e') // 2
+ * @endcode
+ * @since v4.2.0
+ */
+size_t string_position_of(const string_t string, const char character);
+
+/**
+ * @brief Returns the position (index + 1) within the string of the last occurrence of the specified substring (0 if not found).
+ *
+ * @param string
+ * @param character
+ * @return size_t
+ *
+ * @code
+ * string_last_position_of("hello world", 'o') // 8
+ * @endcode
+ * @since v4.2.0
+ */
+size_t string_last_position_of(const string_t string, const char character);
+
+/**
+ * @brief Pads a `string` with another `pad_string` (multiple times, if needed) until the resulting string reaches the `target_length`. The padding is applied from the start (left) of the string.
+ *
+ * @param string The string to pad.
+ * @param pad_string The string to pad the current string with, to the left.
+ * @param target_length
+ * @return string_t
+ *
+ * @code
+ * string_pad_start("hello", " ", 10) // "     hello"
+ * @endcode
+ * @since v4.3.0
+ */
+string_t string_pad_start(const string_t string, const string_t pad_string, size_t target_length);
+
+/**
+ * @brief Pad a number with zeros.
+ *
+ * @param number
+ * @param places
+ * @return string_t
+ *
+ * @code
+ * string_zero_pad(1, 2) // "01"
+ *
+ * string_zero_pad(10, 2) // "10"
+ * @endcode
+ * @since v4.3.0
+ */
+string_t string_zero_pad(uint64_t number, size_t places);
 
 #endif

lib/terminal.c

@@ -1,21 +1,11 @@
 #include "terminal.h"
 
-#include <stdbool.h>
+string_t terminal_input() {
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "character.h"
-#include "dictionary.h"
-#include "linked_list.h"
-#include "queue.h"
-#include "stack.h"
-
-char* terminal_input() {
   char character;
   size_t length = 1;
-  char* string = malloc(length * sizeof(char));
+  string_t string = malloc(length * sizeof(char));
   if (string == NULL) {
+    perror("Error (terminal_input)");
     exit(EXIT_FAILURE);
   }
   *string = '\0';
@@ -23,6 +13,7 @@ char* terminal_input() {
     length++;
     string = realloc(string, length * sizeof(char));
     if (string == NULL) {
+      perror("Error (terminal_input)");
       exit(EXIT_FAILURE);
     }
     character_append(string, character);
@@ -33,7 +24,7 @@ char* terminal_input() {
 void terminal_print_array(void* array, size_t array_size, size_t element_size, void (*print_element)(void*)) {
   printf("[");
   for (size_t index = 0; index < array_size; index++) {
-    void* element = (char*)array + index * element_size;
+    void* element = (string_t)array + index * element_size;
     print_element(element);
     bool is_last = index == array_size - 1;
     if (!is_last) {
@@ -56,21 +47,23 @@ void terminal_print_unsigned_long(void* value) {
 }
 
 void terminal_print_char(void* value) {
-  printf("%c", *(char*)value);
+  printf("%c", *(string_t)value);
 }
 
 void terminal_print_string(void* value) {
-  printf("%s", (char*)value);
+  printf("%s", (string_t)value);
 }
 
 void terminal_print_stack(struct stack* stack, void (*print_element)(void*)) {
   if (stack == NULL) {
+    errno = EINVAL;
+    perror("Error (terminal_print_stack)");
     exit(EXIT_FAILURE);
   }
   struct stack_node* node_current = stack->first;
   while (node_current != NULL) {
     printf("|\t");
-    void* element = (char*)node_current->data;
+    void* element = node_current->data;
     print_element(&element);
     node_current = node_current->next;
     printf("\t|\n");
@@ -79,12 +72,14 @@ void terminal_print_stack(struct stack* stack, void (*print_element)(void*)) {
 
 void terminal_print_queue(struct queue* queue, void (*print_element)(void*)) {
   if (queue == NULL) {
+    errno = EINVAL;
+    perror("Error (terminal_print_queue)");
     exit(EXIT_FAILURE);
   }
   struct queue_node* node_current = queue->first;
   while (node_current != NULL) {
     printf("|\t");
-    void* element = (char*)node_current->data;
+    void* element = node_current->data;
     print_element(&element);
     node_current = node_current->next;
     printf("\t|\n");
@@ -93,11 +88,13 @@ void terminal_print_queue(struct queue* queue, void (*print_element)(void*)) {
 
 void terminal_print_linked_list(struct linked_list* linked_list, void (*print_element)(void*)) {
   if (linked_list == NULL) {
+    errno = EINVAL;
+    perror("Error (terminal_print_linked_list)");
     exit(EXIT_FAILURE);
   }
   struct linked_list_node* node_current = linked_list->head;
   while (node_current != NULL) {
-    void* element = (char*)node_current->data;
+    void* element = (string_t)node_current->data;
     node_current = node_current->next;
     print_element(&element);
     printf(" -> ");
@@ -105,18 +102,26 @@ void terminal_print_linked_list(struct linked_list* linked_list, void (*print_el
   printf("NULL\n");
 }
 
-void terminal_print_dictionary(struct dictionary* dictionary, void (*print_element)(void*)) {
+void terminal_print_hash_map(struct hash_map* hash_map, void (*print_element)(void*)) {
-  if (dictionary == NULL) {
+  if (hash_map == NULL) {
+    errno = EINVAL;
+    perror("Error (terminal_print_hash_map)");
     exit(EXIT_FAILURE);
   }
   printf("{\n");
-  for (size_t index = 0; index < dictionary->length; index++) {
+  string_t* keys = hash_map_get_keys(hash_map);
-    struct dictionary_item* item = dictionary->items[index];
+  for (size_t index = 0; index < hash_map->length; index++) {
+    string_t key = keys[index];
+    void* value = hash_map_get(hash_map, key);
     printf("\t\"");
-    terminal_print_string(item->key);
+    terminal_print_string(key);
     printf("\" -> ");
-    print_element(&item->data);
+    print_element(&value);
     printf("\n");
   }
   printf("}\n");
 }
+
+void terminal_print_array_list(struct array_list* list, void (*print_element)(void*)) {
+  terminal_print_array(list->data, list->size, sizeof(void*), print_element);
+}

lib/terminal.h

@@ -1,38 +1,122 @@
-#ifndef __TERMINAL__
+#ifndef __LIBCPROJECT_TERMINAL__
-#define __TERMINAL__
+#define __LIBCPROJECT_TERMINAL__
 
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
 #include <stdlib.h>
 
-#include "dictionary.h"
+#include "array_list.h"
+#include "character.h"
+#include "hash_map.h"
 #include "linked_list.h"
 #include "queue.h"
 #include "stack.h"
+#include "types.h"
 
 /**
  * @brief Read a line from stdin.
  *
- * @return char*
+ * @return string_t
+ * @since v1.0.0
  */
-char* terminal_input();
+string_t terminal_input();
 
+/**
+ * @brief Print an array.
+ *
+ * @param array
+ * @param array_size
+ * @param element_size
+ * @param print_element
+ * @since v1.0.0
+ */
 void terminal_print_array(void* array, size_t array_size, size_t element_size, void (*print_element)(void*));
 
+/**
+ * @brief Print a int.
+ *
+ * @param value
+ * @since v1.0.0
+ */
 void terminal_print_int(void* value);
 
+/**
+ * @brief Print a long.
+ *
+ * @param value
+ * @since v1.0.0
+ */
 void terminal_print_long(void* value);
 
+/**
+ * @brief Print a unsigned long.
+ *
+ * @param value
+ * @since v1.0.0
+ */
 void terminal_print_unsigned_long(void* value);
 
+/**
+ * @brief Print a char.
+ *
+ * @param value
+ * @since v1.0.0
+ */
 void terminal_print_char(void* value);
 
+/**
+ * @brief Print a string.
+ *
+ * @param value
+ * @since v1.0.0
+ */
 void terminal_print_string(void* value);
 
+/**
+ * @brief Print a stack.
+ *
+ * @param stack
+ * @param print_element
+ * @since v1.0.0
+ */
 void terminal_print_stack(struct stack* stack, void (*print_element)(void*));
 
+/**
+ * @brief Print a queue.
+ *
+ * @param queue
+ * @param print_element
+ * @since v1.0.0
+ */
 void terminal_print_queue(struct queue* queue, void (*print_element)(void*));
 
+/**
+ * @brief Print a linked list.
+ *
+ * @param linked_list
+ * @param print_element
+ * @since v1.0.0
+ */
 void terminal_print_linked_list(struct linked_list* linked_list, void (*print_element)(void*));
 
-void terminal_print_dictionary(struct dictionary* dictionary, void (*print_element)(void*));
+/**
+ * @brief Print a hash map.
+ *
+ * @param hash_map
+ * @param print_element
+ * @since v2.0.0
+ */
+void terminal_print_hash_map(struct hash_map* hash_map, void (*print_element)(void*));
+
+/**
+ * @brief Print an array list.
+ *
+ * @param list
+ * @param print_element
+ * @since v3.0.0
+ */
+void terminal_print_array_list(struct array_list* list, void (*print_element)(void*));
 
 #endif

lib/types.h

@@ -0,0 +1,10 @@
+#ifndef __LIBCPROJECT_TYPES__
+#define __LIBCPROJECT_TYPES__
+
+#include <stdint.h>
+
+typedef uint8_t byte_t;
+
+typedef char* string_t;
+
+#endif

libcproject.h

@@ -1,15 +1,19 @@
 #ifndef __LIBCPROJECT__
 #define __LIBCPROJECT__
 
+#include "lib/array_list.h"
 #include "lib/character.h"
 #include "lib/convert.h"
-#include "lib/dictionary.h"
+#include "lib/date.h"
 #include "lib/filesystem.h"
+#include "lib/hash_map.h"
 #include "lib/linked_list.h"
 #include "lib/mathematics.h"
 #include "lib/queue.h"
 #include "lib/stack.h"
 #include "lib/string.h"
 #include "lib/terminal.h"
+#include "lib/types.h"
+#include "version.h"
 
 #endif

main.c

@@ -4,7 +4,7 @@
 #include "libcproject.h"
 
 int main() {
-  char* string = "Hello, world!";
+  string_t string = "Hello, world!";
   printf("%s\n", string);
   printf("string_length = %ld\n", string_get_length(string));
   return EXIT_SUCCESS;

set_version.c

@@ -3,21 +3,23 @@
 
 #include "libcproject.h"
 
-int main(int argc, char* argv[]) {
+int main(int argc, string_t* argv) {
   if (argc != 2) {
     fprintf(stderr, "Usage: %s <version>\n", argv[0]);
     return EXIT_FAILURE;
   }
-  char* content = "#ifndef __LIBCPROJECT_VERSION__\n";
+  string_t content = string_copy("#ifndef __LIBCPROJECT_VERSION__\n");
-  content = string_concatenate(content, "#define __LIBCPROJECT_VERSION__ \"");
+  string_concatenate(&content, "#define __LIBCPROJECT_VERSION__ \"");
-  content = string_concatenate(content, argv[1]);
+  string_concatenate(&content, argv[1]);
-  content = string_concatenate(content, "\"\n\n");
+  string_concatenate(&content, "\"\n\n");
-  content = string_concatenate(content, "#endif\n");
+  string_concatenate(&content, "#endif\n");
-  int result = filesystem_write("./version.h", content, string_get_length(content));
+  int result = filesystem_write("./version.h", (byte_t*)content, string_get_length(content));
   if (result == -1) {
     fprintf(stderr, "Error: Could not write to file.\n");
+    perror("Error (set_version)");
     return EXIT_FAILURE;
   }
   printf("Success: Version set to %s.\n", argv[1]);
+  free(content);
   return EXIT_SUCCESS;
 }

test/array_list_test.c

@@ -0,0 +1,48 @@
+#include "array_list_test.h"
+
+void array_list_test() {
+  struct array_list *list = array_list_initialization();
+  assert(list->size == 0);
+  array_list_add(list, (void *)'a');
+  array_list_add(list, (void *)'b');
+  array_list_add(list, (void *)'c');
+  array_list_add(list, (void *)'d');
+  array_list_add(list, (void *)'e');
+  array_list_add(list, (void *)'f');
+  assert(list->size == 6);
+  assert(array_list_get(list, 0) == (void *)'a');
+  assert(array_list_get(list, 1) == (void *)'b');
+  assert(array_list_get(list, 2) == (void *)'c');
+  assert(array_list_get(list, 3) == (void *)'d');
+  assert(array_list_get(list, 4) == (void *)'e');
+  assert(array_list_get(list, 5) == (void *)'f');
+  array_list_add(list, (void *)'a');
+  assert(array_list_get(list, 6) == (void *)'a');
+  assert(list->size == 7);
+  array_list_remove(list, 6);
+  assert(list->size == 6);
+  assert(array_list_get(list, 6) == NULL);
+
+  for (size_t index = 0; index < 100; index++) {
+    array_list_add(list, (void *)index);
+  }
+  assert(list->size == 106);
+  assert(array_list_get(list, 100) == (void *)94);
+  assert(array_list_get(list, 101) == (void *)95);
+  array_list_remove(list, 100);
+  assert(list->size == 105);
+  assert(array_list_get(list, 100) == (void *)95);
+
+  array_list_free(list);
+
+  list = array_list_initialization();
+  array_list_add(list, (void *)'a');
+  array_list_add(list, (void *)'b');
+  array_list_add(list, (void *)'c');
+  array_list_remove(list, 1);
+  assert(array_list_get(list, 0) == (void *)'a');
+  assert(array_list_get(list, 1) == (void *)'c');
+  assert(list->size == 2);
+
+  array_list_free(list);
+}

test/array_list_test.h

@@ -0,0 +1,13 @@
+#ifndef __ARRAY_LIST_TEST__
+#define __ARRAY_LIST_TEST__
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
+void array_list_test();
+
+#endif

test/character_test.c

@@ -1,12 +1,5 @@
 #include "character_test.h"
 
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "libcproject.h"
-#include "test.h"
-
 void character_test() {
   character_append_test();
   character_append_at_test();
@@ -27,7 +20,7 @@ void character_append_at_test() {
   character_append_at(string, 'd', 1);
   assert(assert_string_equal(string, "adbc"));
 
-  char string2[5] = "abcd";
+  char string2[6] = "abcd";
   character_append_at(string2, 'e', 4);
   assert(assert_string_equal(string2, "abcde"));
 }

test/character_test.h

@@ -1,6 +1,13 @@
 #ifndef __CHARACTER_TEST__
 #define __CHARACTER_TEST__
 
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+#include "test.h"
+
 void character_test();
 
 void character_append_test();

test/convert_test.c

@@ -1,12 +1,5 @@
 #include "convert_test.h"
 
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "libcproject.h"
-#include "test.h"
-
 void convert_test() {
   convert_character_to_string_test();
   convert_character_to_digit_test();
@@ -17,11 +10,25 @@ void convert_test() {
 }
 
 void convert_character_to_string_test() {
-  assert(assert_string_equal(convert_character_to_string('a'), "a"));
+  string_t result = convert_character_to_string('a');
-  assert(assert_string_equal(convert_character_to_string('A'), "A"));
+  assert(assert_string_equal(result, "a"));
-  assert(assert_string_equal(convert_character_to_string('0'), "0"));
+  free(result);
-  assert(assert_string_equal(convert_character_to_string(' '), " "));
+
-  assert(assert_string_equal(convert_character_to_string('\0'), ""));
+  result = convert_character_to_string('A');
+  assert(assert_string_equal(result, "A"));
+  free(result);
+
+  result = convert_character_to_string('0');
+  assert(assert_string_equal(result, "0"));
+  free(result);
+
+  result = convert_character_to_string(' ');
+  assert(assert_string_equal(result, " "));
+  free(result);
+
+  result = convert_character_to_string('\0');
+  assert(assert_string_equal(result, ""));
+  free(result);
 }
 
 void convert_character_to_digit_test() {
@@ -70,33 +77,109 @@ void convert_string_to_number_test() {
 }
 
 void convert_number_to_string_test() {
-  assert(assert_string_equal(convert_number_to_string(0), "0"));
+  string_t result = convert_number_to_string(0);
-  assert(assert_string_equal(convert_number_to_string(1), "1"));
+  assert(assert_string_equal(result, "0"));
-  assert(assert_string_equal(convert_number_to_string(2), "2"));
+  free(result);
-  assert(assert_string_equal(convert_number_to_string(3), "3"));
+
-  assert(assert_string_equal(convert_number_to_string(4), "4"));
+  result = convert_number_to_string(1);
-  assert(assert_string_equal(convert_number_to_string(5), "5"));
+  assert(assert_string_equal(result, "1"));
-  assert(assert_string_equal(convert_number_to_string(6), "6"));
+  free(result);
-  assert(assert_string_equal(convert_number_to_string(7), "7"));
+
-  assert(assert_string_equal(convert_number_to_string(8), "8"));
+  result = convert_number_to_string(2);
-  assert(assert_string_equal(convert_number_to_string(9), "9"));
+  assert(assert_string_equal(result, "2"));
-  assert(assert_string_equal(convert_number_to_string(10), "10"));
+  free(result);
-  assert(assert_string_equal(convert_number_to_string(11), "11"));
+
-  assert(assert_string_equal(convert_number_to_string(20), "20"));
+  result = convert_number_to_string(3);
-  assert(assert_string_equal(convert_number_to_string(-0), "0"));
+  assert(assert_string_equal(result, "3"));
-  assert(assert_string_equal(convert_number_to_string(-1), "-1"));
+  free(result);
-  assert(assert_string_equal(convert_number_to_string(-20), "-20"));
+
+  result = convert_number_to_string(4);
+  assert(assert_string_equal(result, "4"));
+  free(result);
+
+  result = convert_number_to_string(5);
+  assert(assert_string_equal(result, "5"));
+  free(result);
+
+  result = convert_number_to_string(6);
+  assert(assert_string_equal(result, "6"));
+  free(result);
+
+  result = convert_number_to_string(7);
+  assert(assert_string_equal(result, "7"));
+  free(result);
+
+  result = convert_number_to_string(8);
+  assert(assert_string_equal(result, "8"));
+  free(result);
+
+  result = convert_number_to_string(9);
+  assert(assert_string_equal(result, "9"));
+  free(result);
+
+  result = convert_number_to_string(10);
+  assert(assert_string_equal(result, "10"));
+  free(result);
+
+  result = convert_number_to_string(11);
+  assert(assert_string_equal(result, "11"));
+  free(result);
+
+  result = convert_number_to_string(20);
+  assert(assert_string_equal(result, "20"));
+  free(result);
+
+  result = convert_number_to_string(-0);
+  assert(assert_string_equal(result, "0"));
+  free(result);
+
+  result = convert_number_to_string(-1);
+  assert(assert_string_equal(result, "-1"));
+  free(result);
+
+  result = convert_number_to_string(-20);
+  assert(assert_string_equal(result, "-20"));
+  free(result);
 }
 
 void convert_number_from_base_to_another_test() {
-  assert(assert_string_equal(convert_number_from_base_to_another("15", 10, 16), "F"));
+  string_t result = convert_number_from_base_to_another("15", 10, 16);
-  assert(assert_string_equal(convert_number_from_base_to_another("100000000", 2, 16), "100"));
+  assert(assert_string_equal(result, "F"));
-  assert(assert_string_equal(convert_number_from_base_to_another("FFFFFF", 16, 10), "16777215"));
+  free(result);
-  assert(assert_string_equal(convert_number_from_base_to_another("1D57", 17, 35), "75C"));
+
-  assert(assert_string_equal(convert_number_from_base_to_another("80E", 20, 5), "100324"));
+  result = convert_number_from_base_to_another("100000000", 2, 16);
-  assert(assert_string_equal(convert_number_from_base_to_another("99", 10, 10), "99"));
+  assert(assert_string_equal(result, "100"));
-  assert(assert_string_equal(convert_number_from_base_to_another("3433024", 6, 28), "8008"));
+  free(result);
-  assert(assert_string_equal(convert_number_from_base_to_another("30288G3A", 17, 36), "KF12OI"));
+
-  assert(assert_string_equal(convert_number_from_base_to_another("10", 9, 9), "10"));
+  result = convert_number_from_base_to_another("FFFFFF", 16, 10);
-  assert(assert_string_equal(convert_number_from_base_to_another("10E", 23, 8), "1037"));
+  assert(assert_string_equal(result, "16777215"));
+  free(result);
+
+  result = convert_number_from_base_to_another("1D57", 17, 35);
+  assert(assert_string_equal(result, "75C"));
+  free(result);
+
+  result = convert_number_from_base_to_another("80E", 20, 5);
+  assert(assert_string_equal(result, "100324"));
+  free(result);
+
+  result = convert_number_from_base_to_another("99", 10, 10);
+  assert(assert_string_equal(result, "99"));
+  free(result);
+
+  result = convert_number_from_base_to_another("3433024", 6, 28);
+  assert(assert_string_equal(result, "8008"));
+  free(result);
+
+  result = convert_number_from_base_to_another("30288G3A", 17, 36);
+  assert(assert_string_equal(result, "KF12OI"));
+  free(result);
+
+  result = convert_number_from_base_to_another("10", 9, 9);
+  assert(assert_string_equal(result, "10"));
+  free(result);
+
+  result = convert_number_from_base_to_another("10E", 23, 8);
+  assert(assert_string_equal(result, "1037"));
+  free(result);
 }

test/convert_test.h

@@ -1,6 +1,13 @@
 #ifndef __CONVERT_TEST__
 #define __CONVERT_TEST__
 
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+#include "test.h"
+
 void convert_test();
 
 void convert_character_to_string_test();

test/date_test.c

@@ -0,0 +1,164 @@
+#include "date_test.h"
+
+void date_test() {
+  date_copy_test();
+  date_to_iso_string_test();
+  date_to_iso_string_without_time_test();
+  date_from_iso_string_test();
+  date_get_is_leap_year_test();
+  date_duration_seconds_between_2_dates_test();
+  date_to_utc_test();
+}
+
+void date_copy_test() {
+  struct date *date = malloc(sizeof(struct date));
+  date->year = 2024;
+  date->month = 9;
+  date->day = 10;
+  date->hours = 20;
+  date->minutes = 34;
+  date->seconds = 25;
+  date->milliseconds = 76;
+  date->timezone_utc_offset = 0;
+
+  struct date *date2 = date_copy(date);
+  assert(date != date2);
+  assert(date->year == date2->year);
+  assert(date->month == date2->month);
+  assert(date->day == date2->day);
+  assert(date->hours == date2->hours);
+  assert(date->minutes == date2->minutes);
+  assert(date->seconds == date2->seconds);
+  assert(date->milliseconds == date2->milliseconds);
+  assert(date->timezone_utc_offset == date2->timezone_utc_offset);
+
+  date->year = 2025;
+  assert(date->year == 2025);
+  assert(date2->year == 2024);
+
+  free(date);
+  free(date2);
+}
+
+void date_to_iso_string_test() {
+  struct date *date = malloc(sizeof(struct date));
+  date->year = 2024;
+  date->month = 9;
+  date->day = 10;
+  date->hours = 20;
+  date->minutes = 34;
+  date->seconds = 25;
+  date->milliseconds = 76;
+  date->timezone_utc_offset = 0;
+
+  string_t iso_string = date_to_iso_string(date);
+  assert(assert_string_equal(iso_string, "2024-09-10T20:34:25.076Z"));
+  free(iso_string);
+
+  free(date);
+}
+
+void date_to_iso_string_without_time_test() {
+  struct date *date = malloc(sizeof(struct date));
+  date->year = 2024;
+  date->month = 9;
+  date->day = 10;
+  date->hours = 20;
+  date->minutes = 34;
+  date->seconds = 25;
+  date->milliseconds = 76;
+  date->timezone_utc_offset = 0;
+
+  string_t iso_string = date_to_iso_string_without_time(date);
+  assert(assert_string_equal(iso_string, "2024-09-10"));
+  free(iso_string);
+
+  free(date);
+}
+
+void date_from_iso_string_test() {
+  string_t iso_string = "2024-09-10T20:34:25.076Z";
+  struct date *date = date_from_iso_string(iso_string);
+  assert(date->year == 2024);
+  assert(date->month == 9);
+  assert(date->day == 10);
+  assert(date->hours == 20);
+  assert(date->minutes == 34);
+  assert(date->seconds == 25);
+  assert(date->milliseconds == 76);
+  assert(date->timezone_utc_offset == 0);
+
+  free(date);
+}
+
+void date_get_is_leap_year_test() {
+  assert(date_get_is_leap_year(2020));
+  assert(!date_get_is_leap_year(2021));
+  assert(!date_get_is_leap_year(2022));
+  assert(!date_get_is_leap_year(2023));
+  assert(date_get_is_leap_year(2024));
+}
+
+void date_duration_seconds_between_2_dates_test() {
+  struct date *date1 = date_from_iso_string("2024-09-10T20:34:25.076Z");
+  struct date *date2 = date_from_iso_string("2024-09-10T20:34:25.076Z");
+  assert(date_duration_seconds_between_2_dates(date1, date2) == 0);
+  free(date1);
+  free(date2);
+
+  date1 = date_from_iso_string("2024-09-10T20:34:25.076Z");
+  date2 = date_from_iso_string("2024-09-10T23:34:26.076Z");
+  assert(date_duration_seconds_between_2_dates(date1, date2) == 10801);
+  free(date1);
+  free(date2);
+
+  date1 = date_from_iso_string("2024-09-10T20:34:25.076Z");
+  date2 = date_from_iso_string("2024-09-10T20:48:25.076Z");
+  assert(date_duration_seconds_between_2_dates(date1, date2) == 840);
+  free(date1);
+  free(date2);
+
+  date1 = date_from_iso_string("2024-09-10T20:34:25.076Z");
+  date2 = date_from_iso_string("2024-09-10T20:34:38.076Z");
+  assert(date_duration_seconds_between_2_dates(date1, date2) == 13);
+  free(date1);
+  free(date2);
+}
+
+void date_to_utc_test() {
+  struct date *date = date_from_iso_string("2024-09-10T20:34:25.076Z");
+  date->timezone_utc_offset = 3;
+  date_to_utc(date);
+  assert(date->timezone_utc_offset == 0);
+  string_t iso_string = date_to_iso_string(date);
+  assert(assert_string_equal(iso_string, "2024-09-10T17:34:25.076Z"));
+  free(iso_string);
+  free(date);
+
+  date = date_from_iso_string("2024-09-10T20:34:25.076Z");
+  date->timezone_utc_offset = -3;
+  date_to_utc(date);
+  assert(date->timezone_utc_offset == 0);
+  iso_string = date_to_iso_string(date);
+  assert(assert_string_equal(iso_string, "2024-09-10T23:34:25.076Z"));
+  free(iso_string);
+  free(date);
+
+  date = date_from_iso_string("2024-01-01T00:00:00.000Z");
+  date->timezone_utc_offset = 3;
+  date_to_utc(date);
+  assert(date->timezone_utc_offset == 0);
+  iso_string = date_to_iso_string(date);
+  assert(assert_string_equal(iso_string, "2023-12-31T21:00:00.000Z"));
+  free(iso_string);
+  free(date);
+
+  date = date_from_iso_string("2023-12-31T21:00:00.000Z");
+  date->timezone_utc_offset = -4;
+  date_to_utc(date);
+  assert(date->timezone_utc_offset == 0);
+  iso_string = date_to_iso_string(date);
+  assert(assert_string_equal(iso_string, "2024-01-01T01:00:00.000Z"));
+  free(iso_string);
+  free(date);
+}

test/date_test.h

@@ -0,0 +1,25 @@
+#ifndef __DATE_TEST__
+#define __DATE_TEST__
+
+#include <assert.h>
+
+#include "libcproject.h"
+#include "test.h"
+
+void date_test();
+
+void date_copy_test();
+
+void date_to_iso_string_test();
+
+void date_to_iso_string_without_time_test();
+
+void date_from_iso_string_test();
+
+void date_get_is_leap_year_test();
+
+void date_duration_seconds_between_2_dates_test();
+
+void date_to_utc_test();
+
+#endif

test/dictionary_test.c

@@ -1,33 +0,0 @@
-#include "dictionary_test.h"
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "libcproject.h"
-
-void dictionary_test() {
-  struct dictionary *dictionary = dictionary_initialization();
-  assert(dictionary->length == 0);
-  dictionary_add(dictionary, "key", (void *)'a');
-  dictionary_add(dictionary, "key1", (void *)'b');
-  dictionary_add(dictionary, "key2", (void *)'c');
-  dictionary_add(dictionary, "key3", (void *)'d');
-  dictionary_add(dictionary, "key4", (void *)'e');
-  dictionary_add(dictionary, "key5", (void *)'f');
-  assert(dictionary->length == 6);
-  assert(dictionary_get(dictionary, "key")->data == (void *)'a');
-  assert(dictionary_get(dictionary, "key1")->data == (void *)'b');
-  assert(dictionary_get(dictionary, "key2")->data == (void *)'c');
-  assert(dictionary_get(dictionary, "key3")->data == (void *)'d');
-  assert(dictionary_get(dictionary, "key4")->data == (void *)'e');
-  assert(dictionary_get(dictionary, "key5")->data == (void *)'f');
-  dictionary_add(dictionary, "key5", (void *)'a');
-  assert(dictionary_get(dictionary, "key5")->data == (void *)'a');
-  assert(dictionary_contains_key(dictionary, "key5"));
-  assert(!dictionary_contains_key(dictionary, "invalid key"));
-  assert(dictionary_contains_key(dictionary, "key5"));
-  dictionary_remove(dictionary, "key5");
-  assert(dictionary->length == 5);
-  assert(!dictionary_contains_key(dictionary, "key5"));
-}

test/dictionary_test.h

@@ -1,6 +0,0 @@
-#ifndef __DICTIONARY_TEST__
-#define __DICTIONARY_TEST__
-
-void dictionary_test();
-
-#endif

test/hash_map_test.c

@@ -0,0 +1,28 @@
+#include "hash_map_test.h"
+
+void hash_map_test() {
+  struct hash_map *hash_map = hash_map_initialization();
+  assert(hash_map->length == 0);
+  hash_map_add(hash_map, "key", (void *)'a');
+  hash_map_add(hash_map, "key1", (void *)'b');
+  hash_map_add(hash_map, "key2", (void *)'c');
+  hash_map_add(hash_map, "key3", (void *)'d');
+  hash_map_add(hash_map, "key4", (void *)'e');
+  hash_map_add(hash_map, "key5", (void *)'f');
+  assert(hash_map->length == 6);
+  assert(hash_map_get(hash_map, "key") == (void *)'a');
+  assert(hash_map_get(hash_map, "key1") == (void *)'b');
+  assert(hash_map_get(hash_map, "key2") == (void *)'c');
+  assert(hash_map_get(hash_map, "key3") == (void *)'d');
+  assert(hash_map_get(hash_map, "key4") == (void *)'e');
+  assert(hash_map_get(hash_map, "key5") == (void *)'f');
+  hash_map_add(hash_map, "key5", (void *)'a');
+  assert(hash_map_get(hash_map, "key5") == (void *)'a');
+  assert(hash_map_contains_key(hash_map, "key5"));
+  assert(!hash_map_contains_key(hash_map, "invalid key"));
+  assert(hash_map_contains_key(hash_map, "key5"));
+  hash_map_remove(hash_map, "key5");
+  assert(hash_map->length == 5);
+  assert(!hash_map_contains_key(hash_map, "key5"));
+  hash_map_free(hash_map);
+}

test/hash_map_test.h

@@ -0,0 +1,12 @@
+#ifndef __HASH_MAP_TEST__
+#define __HASH_MAP_TEST__
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
+void hash_map_test();
+
+#endif

test/linked_list_test.c

@@ -1,12 +1,5 @@
 #include "linked_list_test.h"
 
-#include <assert.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "libcproject.h"
-
 void linked_list_test() {
   linked_list_initialization_test();
   linked_list_add_in_head_test();
@@ -20,6 +13,7 @@ void linked_list_initialization_test() {
   struct linked_list *list = linked_list_initialization();
   assert(list->length == 0);
   assert(list->head == NULL);
+  linked_list_free(list);
 }
 
 void linked_list_add_in_head_test() {
@@ -32,6 +26,7 @@ void linked_list_add_in_head_test() {
   assert(((uintptr_t)list->head->next->data) == 8);
   assert(((uintptr_t)list->head->next->next->data) == 4);
   assert(list->head->next->next->next == NULL);
+  linked_list_free(list);
 }
 
 void linked_list_delete_in_head_test() {
@@ -44,6 +39,7 @@ void linked_list_delete_in_head_test() {
   assert(((uintptr_t)list->head->data) == 8);
   assert(((uintptr_t)list->head->next->data) == 4);
   assert(list->head->next->next == NULL);
+  linked_list_free(list);
 }
 
 void linked_list_add_after_last_test() {
@@ -61,6 +57,7 @@ void linked_list_add_after_last_test() {
   assert(((uintptr_t)list->head->next->data) == 8);
   assert(((uintptr_t)list->head->next->next->data) == 4);
   assert(((uintptr_t)list->head->next->next->next->data) == 18);
+  linked_list_free(list);
 }
 
 void linked_list_reverse_test() {
@@ -81,6 +78,8 @@ void linked_list_reverse_test() {
   assert((list_reversed->head->next->data) == (void *)'C');
   assert((list_reversed->head->next->next->data) == (void *)'B');
   assert((list_reversed->head->next->next->next->data) == (void *)'A');
+  linked_list_free(list);
+  linked_list_free(list_reversed);
 }
 
 void linked_list_reverse_mutate_test() {
@@ -96,4 +95,5 @@ void linked_list_reverse_mutate_test() {
   assert((list->head->next->data) == (void *)'C');
   assert((list->head->next->next->data) == (void *)'B');
   assert((list->head->next->next->next->data) == (void *)'A');
+  linked_list_free(list);
 }

test/linked_list_test.h

@@ -1,6 +1,13 @@
 #ifndef __LINKED_LIST_TEST__
 #define __LINKED_LIST_TEST__
 
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
 void linked_list_test();
 
 void linked_list_initialization_test();

test/main.c

@@ -1,9 +1,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "array_list_test.h"
 #include "character_test.h"
 #include "convert_test.h"
-#include "dictionary_test.h"
+#include "date_test.h"
+#include "hash_map_test.h"
 #include "linked_list_test.h"
 #include "mathematics_test.h"
 #include "queue_test.h"
@@ -11,9 +13,11 @@
 #include "string_test.h"
 
 int main() {
+  array_list_test();
   character_test();
   convert_test();
-  dictionary_test();
+  date_test();
+  hash_map_test();
   linked_list_test();
   mathematics_test();
   queue_test();

test/mathematics_test.c

@@ -1,15 +1,16 @@
 #include "mathematics_test.h"
 
-#include <assert.h>
-
-#include "libcproject.h"
-
 void mathematics_test() {
   mathematics_absolute_value_test();
   mathematics_pow_test();
   mathematics_root_test();
   mathematics_square_root_test();
   mathematics_factorial_test();
+  mathematics_opposite_test();
+  mathematics_max_test();
+  mathematics_max_values_test();
+  mathematics_min_test();
+  mathematics_min_values_test();
 }
 
 void mathematics_absolute_value_test() {
@@ -60,3 +61,38 @@ void mathematics_factorial_test() {
   assert(mathematics_factorial(9) == 362880);
   assert(mathematics_factorial(10) == 3628800);
 }
+
+void mathematics_opposite_test() {
+  assert(mathematics_opposite(-7) == 7);
+  assert(mathematics_opposite(7) == -7);
+}
+
+void mathematics_max_test() {
+  assert(mathematics_max(0, 0) == 0);
+  assert(mathematics_max(0, 1) == 1);
+  assert(mathematics_max(2, 0) == 2);
+  assert(mathematics_max(54, 37) == 54);
+}
+
+void mathematics_max_values_test() {
+  int64_t values[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+  assert(mathematics_max_values(values, 10) == 9);
+
+  int64_t values2[] = {8, 6, 4, 7};
+  assert(mathematics_max_values(values2, 4) == 8);
+}
+
+void mathematics_min_test() {
+  assert(mathematics_min(0, 0) == 0);
+  assert(mathematics_min(3, 5) == 3);
+  assert(mathematics_min(2, 1) == 1);
+  assert(mathematics_min(54, 37) == 37);
+}
+
+void mathematics_min_values_test() {
+  int64_t values[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+  assert(mathematics_min_values(values, 10) == 0);
+
+  int64_t values2[] = {9, 6, 8, 7};
+  assert(mathematics_min_values(values2, 4) == 6);
+}

test/mathematics_test.h

@@ -1,6 +1,10 @@
 #ifndef __MATHEMATICS_TEST__
 #define __MATHEMATICS_TEST__
 
+#include <assert.h>
+
+#include "libcproject.h"
+
 void mathematics_test();
 
 void mathematics_absolute_value_test();
@@ -13,4 +17,14 @@ void mathematics_square_root_test();
 
 void mathematics_factorial_test();
 
+void mathematics_opposite_test();
+
+void mathematics_max_test();
+
+void mathematics_max_values_test();
+
+void mathematics_min_test();
+
+void mathematics_min_values_test();
+
 #endif

test/queue_test.c

@@ -1,11 +1,5 @@
 #include "queue_test.h"
 
-#include <assert.h>
-#include <stdint.h>
-#include <stdlib.h>
-
-#include "libcproject.h"
-
 void queue_test() {
   queue_initialization_test();
   queue_push_test();
@@ -16,6 +10,7 @@ void queue_initialization_test() {
   struct queue *queue = queue_initialization();
   assert(queue->length == 0);
   assert(queue->first == NULL);
+  queue_free(queue);
 }
 
 void queue_push_test() {
@@ -28,6 +23,7 @@ void queue_push_test() {
   assert(((uintptr_t)queue->first->next->data) == 8);
   assert(((uintptr_t)queue->first->next->next->data) == 15);
   assert(queue->first->next->next->next == NULL);
+  queue_free(queue);
 }
 
 void queue_pop_test() {
@@ -41,4 +37,5 @@ void queue_pop_test() {
   assert(((uintptr_t)queue->first->data) == 8);
   assert(((uintptr_t)queue->first->next->data) == 15);
   assert(queue->first->next->next == NULL);
+  queue_free(queue);
 }

test/queue_test.h

@@ -1,6 +1,12 @@
 #ifndef __QUEUE_TEST__
 #define __QUEUE_TEST__
 
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
 void queue_test();
 
 void queue_initialization_test();

test/stack_test.c

@@ -1,11 +1,5 @@
 #include "stack_test.h"
 
-#include <assert.h>
-#include <stdint.h>
-#include <stdlib.h>
-
-#include "libcproject.h"
-
 void stack_test() {
   stack_initialization_test();
   stack_push_test();
@@ -16,6 +10,7 @@ void stack_initialization_test() {
   struct stack *stack = stack_initialization();
   assert(stack->length == 0);
   assert(stack->first == NULL);
+  stack_free(stack);
 }
 
 void stack_push_test() {
@@ -28,6 +23,7 @@ void stack_push_test() {
   assert(((uintptr_t)stack->first->next->data) == 8);
   assert(((uintptr_t)stack->first->next->next->data) == 4);
   assert(stack->first->next->next->next == NULL);
+  stack_free(stack);
 }
 
 void stack_pop_test() {
@@ -41,4 +37,5 @@ void stack_pop_test() {
   assert(((uintptr_t)stack->first->data) == 8);
   assert(((uintptr_t)stack->first->next->data) == 4);
   assert(stack->first->next->next == NULL);
+  stack_free(stack);
 }

test/stack_test.h

@@ -1,6 +1,12 @@
 #ifndef __STACK_TEST__
 #define __STACK_TEST__
 
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
 void stack_test();
 
 void stack_initialization_test();

test/string_test.c

@@ -1,17 +1,11 @@
 #include "string_test.h"
 
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "libcproject.h"
-#include "test.h"
-
 void string_test() {
   string_get_length_test();
   string_to_uppercase_test();
   string_to_lowercase_test();
   string_replace_test();
+  string_remove_character_test();
   string_trim_start_test();
   string_trim_end_test();
   string_trim_test();
@@ -31,81 +25,102 @@ void string_test() {
   string_get_last_occurence_of_character_test();
   string_starts_with_test();
   string_ends_with_test();
+  string_position_of_test();
+  string_last_position_of_test();
+  string_pad_start_test();
+  string_zero_pad_test();
 }
 
 void string_get_length_test() {
-  char *string = "Hello World!";
+  string_t string = "Hello World!";
   size_t string_length = string_get_length(string);
   assert(string_length == 12);
+  assert(strlen(string) == string_length);
 }
 
 void string_to_uppercase_test() {
-  char *string = "heLlO world";
+  string_t string = string_copy("heLlO world");
-  string = string_to_uppercase(string);
+  string_to_uppercase(string);
   assert(assert_string_equal(string, "HELLO WORLD"));
+  free(string);
 }
 
 void string_to_lowercase_test() {
-  char *string = "HellO WoRLd";
+  string_t string = string_copy("HellO WoRLd");
-  string = string_to_lowercase(string);
+  string_to_lowercase(string);
   assert(assert_string_equal(string, "hello world"));
+  free(string);
 }
 
 void string_replace_test() {
-  char *string = "hello world";
+  string_t string = string_copy("hello world");
-  string = string_replace(string, 'l', 'z');
+  string_replace(string, 'l', 'z');
   assert(assert_string_equal(string, "hezzo worzd"));
+  free(string);
+}
+
+void string_remove_character_test() {
+  string_t string = string_copy("hello world");
+  string_remove_character(string, 'l');
+  assert(assert_string_equal(string, "heo word"));
+  free(string);
 }
 
 void string_trim_start_test() {
-  char *string = "      hello world      ";
+  string_t string = string_copy("      hello world      ");
-  string = string_trim_start(string);
+  string_trim_start(string, ' ');
   assert(assert_string_equal(string, "hello world      "));
+  free(string);
 }
 
 void string_trim_end_test() {
-  char *string = "      hello world      ";
+  string_t string = string_copy("      hello world      ");
-  string = string_trim_end(string);
+  string_trim_end(string, ' ');
   assert(assert_string_equal(string, "      hello world"));
+  free(string);
 }
 
 void string_trim_test() {
-  char *string = "      hello world      ";
+  string_t string = string_copy("      hello world      ");
-  string = string_trim(string);
+  string_trim(string, ' ');
   assert(assert_string_equal(string, "hello world"));
+  free(string);
 }
 
 void string_copy_test() {
-  char *string = "hello world";
+  string_t string = "hello world";
-  char *string2 = string_copy(string);
+  string_t string2 = string_copy(string);
   assert(assert_string_equal(string, string2));
   string2[0] = 'a';
   assert(assert_string_not_equal(string, string2));
   assert(assert_string_equal(string, "hello world"));
   assert(assert_string_equal(string2, "aello world"));
+  free(string2);
 }
 
 void string_capitalize_test() {
-  char *string = "hello world";
+  string_t string = string_copy("hello world");
-  string = string_capitalize(string);
+  string_capitalize(string);
   assert(assert_string_equal(string, "Hello world"));
+  free(string);
 }
 
 void string_total_occurrences_of_character_test() {
-  char *string = "hello world";
+  string_t string = "hello world";
   assert(string_total_occurrences_of_character(string, 'l') == 3);
 }
 
 void string_reverse_test() {
-  char *string = "hello world";
+  string_t string = string_copy("hello world");
-  string = string_reverse(string);
+  string_reverse(string);
   assert(assert_string_equal(string, "dlrow olleh"));
+  free(string);
 }
 
 void string_equals_test() {
-  char *string1 = "hello world";
+  string_t string1 = "hello world";
-  char *string2 = "dlrow olleh";
+  string_t string2 = "dlrow olleh";
-  char *string3 = "dlrow olleh";
+  string_t string3 = "dlrow olleh";
   assert(!string_equals(string1, string2));
   assert(string_equals(string1, string1));
   assert(string_equals(string2, string3));
@@ -124,29 +139,46 @@ void string_get_is_integer_test() {
 }
 
 void string_split_test() {
-  char *string = "abc def ghij kl";
+  string_t string = "abc def ghij kl";
   size_t result_length = 0;
-  char **result = string_split(string, ' ', &result_length);
+  string_t* result = string_split(string, ' ', &result_length);
   assert(result_length == 4);
   assert(assert_string_equal(result[0], "abc"));
   assert(assert_string_equal(result[1], "def"));
   assert(assert_string_equal(result[2], "ghij"));
   assert(assert_string_equal(result[3], "kl"));
+  for (size_t index = 0; index < result_length; index++) {
+    free(result[index]);
+  }
+  free(result);
 }
 
 void string_join_test() {
-  char *string = "abc def ghij kl";
+  string_t string = "abc def ghij kl";
   size_t result_length = 0;
-  char **result = string_split(string, ' ', &result_length);
+  string_t* result = string_split(string, ' ', &result_length);
-  char *new_string = string_join(result, ' ', result_length);
+  string_t new_string = string_join(result, ' ', result_length);
-  char *new_string2 = string_join(result, '+', result_length);
+  string_t new_string2 = string_join(result, '+', result_length);
   assert(assert_string_equal(new_string, string));
   assert(assert_string_equal(new_string2, "abc+def+ghij+kl"));
+  free(new_string);
+  free(new_string2);
+  for (size_t index = 0; index < result_length; index++) {
+    free(result[index]);
+  }
+  free(result);
 }
 
 void string_concatenate_test() {
-  assert(assert_string_equal(string_concatenate("abc", "def"), "abcdef"));
+  string_t result = string_copy("abc");
-  assert(assert_string_equal(string_concatenate("abc ", " defghi"), "abc  defghi"));
+  string_concatenate(&result, "def");
+  assert(assert_string_equal(result, "abcdef"));
+  free(result);
+
+  result = string_copy("abcz");
+  string_concatenate(&result, "  defghi");
+  assert(assert_string_equal(result, "abcz  defghi"));
+  free(result);
 }
 
 void string_get_has_unique_characters_test() {
@@ -156,13 +188,14 @@ void string_get_has_unique_characters_test() {
 }
 
 void string_substring_test() {
-  char *string = "abcdef";
+  string_t string = "abcdef";
-  char *substring = string_substring(string, 1, 3);
+  string_t substring = string_substring(string, 1, 3);
   assert(assert_string_equal(substring, "bcd"));
+  free(substring);
 }
 
 void string_get_is_substring_test() {
-  char *string = "abcdef";
+  string_t string = "abcdef";
   assert(string_get_is_substring(string, "abc"));
   assert(string_get_is_substring(string, "bcd"));
   assert(string_get_is_substring(string, "de"));
@@ -174,33 +207,61 @@ void string_get_is_substring_test() {
 }
 
 void string_get_formatted_number_test() {
-  assert(assert_string_equal(string_get_formatted_number(1000, " "), "1 000"));
+  string_t result = string_get_formatted_number(1000, " ");
-  assert(assert_string_equal(string_get_formatted_number(123, ","), "123"));
+  assert(assert_string_equal(result, "1 000"));
-  assert(assert_string_equal(string_get_formatted_number(1234, ","), "1,234"));
+  free(result);
-  assert(assert_string_equal(string_get_formatted_number(12345, ","), "12,345"));
+
-  assert(assert_string_equal(string_get_formatted_number(123456, ","), "123,456"));
+  result = string_get_formatted_number(123, ",");
-  assert(assert_string_equal(string_get_formatted_number(1234567, ","), "1,234,567"));
+  assert(assert_string_equal(result, "123"));
-  assert(assert_string_equal(string_get_formatted_number(12345678, ","), "12,345,678"));
+  free(result);
-  assert(assert_string_equal(string_get_formatted_number(123456789, ","), "123,456,789"));
+
-  assert(assert_string_equal(string_get_formatted_number(1234567890, ","), "1,234,567,890"));
+  result = string_get_formatted_number(1234, ",");
-  assert(assert_string_equal(string_get_formatted_number(-123, ","), "-123"));
+  assert(assert_string_equal(result, "1,234"));
-  assert(assert_string_equal(string_get_formatted_number(-1234, ","), "-1,234"));
+  free(result);
-  assert(assert_string_equal(string_get_formatted_number(-12345, ","), "-12,345"));
+
-  assert(assert_string_equal(string_get_formatted_number(-123456, ","), "-123,456"));
+  result = string_get_formatted_number(12345, ",");
-  assert(assert_string_equal(string_get_formatted_number(-1234567, ","), "-1,234,567"));
+  assert(assert_string_equal(result, "12,345"));
-  assert(assert_string_equal(string_get_formatted_number(-12345678, ","), "-12,345,678"));
+  free(result);
-  assert(assert_string_equal(string_get_formatted_number(-123456789, ","), "-123,456,789"));
+
-  assert(assert_string_equal(string_get_formatted_number(-1234567890, ","), "-1,234,567,890"));
+  result = string_get_formatted_number(-123, ",");
+  assert(assert_string_equal(result, "-123"));
+  free(result);
+
+  result = string_get_formatted_number(-1234, ",");
+  assert(assert_string_equal(result, "-1,234"));
+  free(result);
+
+  result = string_get_formatted_number(-1234567890, ",");
+  assert(assert_string_equal(result, "-1,234,567,890"));
+  free(result);
 }
 
 void string_get_last_occurence_of_character_test() {
-  char *string = "abcdef";
+  string_t string = "abcdef";
-  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'a'), "abcdef"));
+
-  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'b'), "bcdef"));
+  string_t result = string_get_last_occurence_of_character(string, 'a');
-  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'c'), "cdef"));
+  assert(assert_string_equal(result, "abcdef"));
-  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'd'), "def"));
+  free(result);
-  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'e'), "ef"));
+
-  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'f'), "f"));
+  result = string_get_last_occurence_of_character(string, 'b');
+  assert(assert_string_equal(result, "bcdef"));
+  free(result);
+
+  result = string_get_last_occurence_of_character(string, 'c');
+  assert(assert_string_equal(result, "cdef"));
+  free(result);
+
+  result = string_get_last_occurence_of_character(string, 'd');
+  assert(assert_string_equal(result, "def"));
+  free(result);
+
+  result = string_get_last_occurence_of_character(string, 'e');
+  assert(assert_string_equal(result, "ef"));
+  free(result);
+
+  result = string_get_last_occurence_of_character(string, 'f');
+  assert(assert_string_equal(result, "f"));
+  free(result);
 }
 
 void string_starts_with_test() {
@@ -220,3 +281,55 @@ void string_ends_with_test() {
   assert(!string_ends_with("abcdef", "bcd"));
   assert(!string_ends_with("abcdef", "abcdefg"));
 }
+
+void string_position_of_test() {
+  assert(string_position_of("hello world", 'e') == 2);
+  assert(string_position_of("hello world", 'o') == 5);
+  assert(string_position_of("abcdef", 'a') == 1);
+  assert(string_position_of("abcdef", 'b') == 2);
+  assert(string_position_of("abcdef", 'c') == 3);
+  assert(string_position_of("abcdef", 'd') == 4);
+  assert(string_position_of("abcdef", 'e') == 5);
+  assert(string_position_of("abcdef", 'f') == 6);
+  assert(string_position_of("abcdef", 'g') == 0);
+}
+
+void string_last_position_of_test() {
+  assert(string_last_position_of("hello world", 'e') == 2);
+  assert(string_last_position_of("hello world", 'o') == 8);
+  assert(string_last_position_of("abcdef", 'a') == 1);
+  assert(string_last_position_of("abcdef", 'b') == 2);
+  assert(string_last_position_of("abcdef", 'c') == 3);
+  assert(string_last_position_of("abcdef", 'd') == 4);
+  assert(string_last_position_of("abcdef", 'e') == 5);
+  assert(string_last_position_of("abcdef", 'f') == 6);
+  assert(string_last_position_of("abcdef", 'g') == 0);
+}
+
+void string_pad_start_test() {
+  string_t result = string_pad_start("hello", "ab", 10);
+  assert(assert_string_equal(result, "ababahello"));
+  free(result);
+
+  result = string_pad_start("hello", "ab", 4);
+  assert(assert_string_equal(result, "hell"));
+  free(result);
+
+  result = string_pad_start("hello", "ab", 5);
+  assert(assert_string_equal(result, "hello"));
+  free(result);
+
+  result = string_pad_start("hello", "ab", 6);
+  assert(assert_string_equal(result, "ahello"));
+  free(result);
+}
+
+void string_zero_pad_test() {
+  string_t result = string_zero_pad(1, 2);
+  assert(assert_string_equal(result, "01"));
+  free(result);
+
+  result = string_zero_pad(10, 2);
+  assert(assert_string_equal(result, "10"));
+  free(result);
+}

test/string_test.h

@@ -1,6 +1,13 @@
 #ifndef __STRING_TEST__
 #define __STRING_TEST__
 
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+#include "test.h"
+
 void string_test();
 
 void string_get_length_test();
@@ -11,6 +18,8 @@ void string_to_lowercase_test();
 
 void string_replace_test();
 
+void string_remove_character_test();
+
 void string_trim_start_test();
 
 void string_trim_end_test();
@@ -49,4 +58,12 @@ void string_starts_with_test();
 
 void string_ends_with_test();
 
+void string_position_of_test();
+
+void string_last_position_of_test();
+
+void string_pad_start_test();
+
+void string_zero_pad_test();
+
 #endif

test/test.c

@@ -1,8 +1,6 @@
-#include <stdbool.h>
+#include "test.h"
-#include <stdio.h>
-#include <string.h>
 
-bool assert_string_equal(const char *actual, const char *expected) {
+bool assert_string_equal(const string_t actual, const string_t expected) {
   if (strcmp(expected, actual) != 0) {
     printf("FAIL: expected = \"%s\" ; actual = \"%s\"\n", expected, actual);
     return false;
@@ -10,7 +8,7 @@ bool assert_string_equal(const char *actual, const char *expected) {
   return true;
 }
 
-bool assert_string_not_equal(const char *actual, const char *expected) {
+bool assert_string_not_equal(const string_t actual, const string_t expected) {
   if (strcmp(expected, actual) == 0) {
     printf("FAIL: expected = \"%s\" ; actual = \"%s\"\n", expected, actual);
     return false;

test/test.h

@@ -2,9 +2,13 @@
 #define __TEST__
 
 #include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
 
-bool assert_string_equal(const char *actual, const char *expected);
+#include "libcproject.h"
 
-bool assert_string_not_equal(const char *actual, const char *expected);
+bool assert_string_equal(const string_t actual, const string_t expected);
+
+bool assert_string_not_equal(const string_t actual, const string_t expected);
 
 #endif

version.h

@@ -1,4 +1,4 @@
 #ifndef __LIBCPROJECT_VERSION__
-#define __LIBCPROJECT_VERSION__ "1.1.0"
+#define __LIBCPROJECT_VERSION__ "4.3.0"
 
 #endif