fix(solutions): memory issues thanks to -fsanitize=address flag with gcc

challenges/slugify/solutions/c/function/character.c

@@ -1,9 +1,5 @@
 #include "character.h"
 
-#include <stdbool.h>
-#include <stdlib.h>
-#include <string.h>
-
 void character_append(char* string, char character) {
   size_t length = strlen(string);
   string[length] = character;

challenges/slugify/solutions/c/function/character.h

@@ -2,6 +2,8 @@
 #define __CHARACTER__
 
 #include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
 
 /**
  * @brief Append a character to a string, assuming string points to an array

challenges/slugify/solutions/c/function/input.c

@@ -1,10 +1,5 @@
 #include "input.h"
 
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "character.h"
-
 char* input() {
   char character;
   size_t length = 1;

challenges/slugify/solutions/c/function/input.h

@@ -1,6 +1,11 @@
 #ifndef __INPUT__
 #define __INPUT__
 
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "character.h"
+
 /**
  * @brief Read a line from stdin.
  *

challenges/slugify/solutions/c/function/solution.c

@@ -7,11 +7,12 @@
 
 int main() {
   char* string = input();
-  string = string_trim(string, ' ');
-  string = string_trim(string, '-');
-  string = string_to_lowercase(string);
-  string = string_slugify(string);
-  printf("%s\n", string);
+  string_trim(string, ' ');
+  string_trim(string, '-');
+  string_to_lowercase(string);
+  char* result = string_slugify(string);
+  printf("%s\n", result);
   free(string);
+  free(result);
   return EXIT_SUCCESS;
 }

challenges/slugify/solutions/c/function/string.c

@@ -1,66 +1,67 @@
 #include "string.h"
 
-#include <stdbool.h>
-#include <stdlib.h>
-#include <string.h>
+size_t string_get_length(const char* string) {
+  size_t length = 0;
+  while (string[length] != '\0') {
+    length++;
+  }
+  return length;
+}
 
-#include "character.h"
+void string_to_lowercase(char* string) {
+  size_t string_length = string_get_length(string);
+  for (size_t index = 0; index < string_length; index++) {
+    string[index] = character_to_lower(string[index]);
+  }
+  string[string_length] = '\0';
+}
 
-char* string_trim_start(char* string, char character) {
-  size_t string_length = strlen(string);
-  char* result = malloc(sizeof(char) * (string_length + 1));
+void string_trim_start(char* string, char character) {
+  size_t string_length = string_get_length(string);
   size_t index_space = 0;
   while (string[index_space] == character) {
     index_space++;
   }
-  for (size_t index = index_space; index < string_length; index++) {
-    character_append(result, string[index]);
+  for (size_t index = 0; index < string_length - index_space; index++) {
+    string[index] = string[index + index_space];
   }
-  return result;
+  string[string_length - index_space] = '\0';
 }
 
-char* string_trim_end(char* string, char character) {
-  size_t string_length = strlen(string);
-  char* result = malloc(sizeof(char) * (string_length + 1));
+void string_trim_end(char* string, char character) {
+  size_t string_length = string_get_length(string);
   size_t index_space = string_length - 1;
   while (string[index_space] == character) {
     index_space--;
   }
-  for (size_t index = 0; index < index_space + 1; index++) {
-    character_append(result, string[index]);
-  }
-  return result;
+  string[index_space + 1] = '\0';
 }
 
-char* string_trim(char* string, char character) {
-  char* result = string_trim_start(string, character);
-  result = string_trim_end(result, character);
-  return result;
-}
-
-char* string_to_lowercase(char* string) {
-  size_t string_length = strlen(string);
-  char* result = malloc(sizeof(char) * (string_length + 1));
-  for (size_t index = 0; index < string_length; index++) {
-    character_append(result, character_to_lower(string[index]));
-  }
-  return result;
+void string_trim(char* string, char character) {
+  string_trim_start(string, character);
+  string_trim_end(string, character);
 }
 
 char* string_slugify(char* string) {
   size_t string_length = strlen(string);
   char* result = malloc(sizeof(char) * (string_length + 1));
-  int words = 0;
+  result[0] = '\0';
+  size_t words = 0;
   char* current = malloc(sizeof(char) * (string_length + 1));
+  current[0] = '\0';
+  size_t current_index = 0;
   for (size_t index = 0; index < string_length; index++) {
     if (string[index] == ' ' || (string[index] == '-' && strlen(current) > 0)) {
       strcat(result, current);
       character_append(result, '-');
       memset(current, 0, sizeof(char) * (string_length + 1));
-      words++;
+      current_index = 0;
+      words += 1;
     } else {
       if (character_is_alphanumeric(string[index])) {
-        character_append(current, string[index]);
+        current[current_index] = string[index];
+        current_index += 1;
+        current[current_index] = '\0';
       }
     }
   }

challenges/slugify/solutions/c/function/string.h

@@ -1,37 +1,55 @@
 #ifndef __STRING__
 #define __STRING__
 
-/**
- * @brief Removes all `character` from the start of a string.
- *
- * @param string
- * @return char*
- */
-char* string_trim_start(char* string, char character);
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "character.h"
 
 /**
- * @brief Removes all `character` from the end of a string.
+ * @brief Return the length of a string (excluding '\0').
  *
  * @param string
- * @return char*
+ * @return size_t
  */
-char* string_trim_end(char* string, char character);
-
-/**
- * @brief Removes all `character` from the start and end of a string.
- *
- * @param string
- * @return char*
- */
-char* string_trim(char* string, char character);
+size_t string_get_length(const char* string);
 
 /**
  * @brief Converts all the alphabetic characters in a string to lowercase.
  *
+ * NOTE: Mutates the string.
+ *
  * @param string
- * @return char*
  */
-char* string_to_lowercase(char* string);
+void string_to_lowercase(char* string);
+
+/**
+ * @brief Removes all `character` from the start of a string.
+ *
+ * NOTE: Mutates the string.
+ *
+ * @param string
+ */
+void string_trim_start(char* string, char character);
+
+/**
+ * @brief Removes all `character` from the end of a string.
+ *
+ * NOTE: Mutates the string.
+ *
+ * @param string
+ */
+void string_trim_end(char* string, char character);
+
+/**
+ * @brief Removes all `character` from the start and end of a string.
+ *
+ * NOTE: Mutates the string.
+ *
+ * @param string
+ */
+void string_trim(char* string, char character);
 
 /**
  * @brief Generate a slug from a string.