feat: add string_zero_pad

lib/string.c

@@ -431,3 +431,12 @@ string_t string_pad_start(const string_t string, const string_t pad_string, size
   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

@@ -298,4 +298,16 @@ size_t string_last_position_of(const string_t string, const char character);
  */
 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
+ * @example zero_pad(1, 2) // "01"
+ * @example zero_pad(10, 2) // "10"
+ * @since vTODO
+ */
+string_t string_zero_pad(uint64_t number, size_t places);
+
 #endif

test/string_test.c

@@ -28,6 +28,7 @@ void string_test() {
   string_position_of_test();
   string_last_position_of_test();
   string_pad_start_test();
+  string_zero_pad_test();
 }
 
 void string_get_length_test() {
@@ -322,3 +323,13 @@ void string_pad_start_test() {
   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

@@ -64,4 +64,6 @@ void string_last_position_of_test();
 
 void string_pad_start_test();
 
+void string_zero_pad_test();
+
 #endif