refactor: string extend method

string/mystring.h

@@ -1,108 +1,119 @@
-#ifndef MYCLIB_STRING_H
-#define MYCLIB_STRING_H
-
-#include <stddef.h>
-#include <threads.h>
-
-/**
- * @brief Thread-safe dynamic string structure.
- */
-typedef struct mcl_string {
-	char *data;		 /**< Pointer to null-terminated string data */
-	size_t size;	 /**< Current length (excluding null terminator) */
-	size_t capacity; /**< Allocated capacity including null terminator */
-	mtx_t lock;		 /**< Mutex for thread safety */
-} mcl_string_s;
-
-/**
- * @brief Create a new string initialized with the given text.
- *
- * @param text Initial text.
- * @param initial_capacity Initial buffer capacity (including null terminator). Pass 0 to auto-calculate.
- * @return Pointer to the new string, or NULL on failure.
- */
-mcl_string_s *mcl_string_new(const char *text, size_t initial_capacity);
-
-/**
- * @brief Free the string and its resources.
- *
- * @param string String to free (safe to call with NULL).
- */
-void mcl_string_free(mcl_string_s *string);
-
-/**
- * @brief Append text to the string.
- *
- * @param string String to modify.
- * @param text Text to append.
- * @return 0 on success, -1 on failure.
- */
-int mcl_string_append(mcl_string_s *string, const char *text);
-
-/**
- * @brief Extend by adding another string.
- *
- * @param destination Destination string.
- * @param source Source string.
- * @return 0 on success, -1 on failure.
- */
-int mcl_string_extend(mcl_string_s *destination, mcl_string_s *source);
-
-/**
- * @brief Clear the string content without freeing the memory.
- *
- * @param string String to clear.
- */
-void mcl_string_clear(mcl_string_s *string);
-
-/**
- * @brief Get the current length of the string.
- *
- * @param string String to query.
- * @return Length excluding null terminator, or 0 if NULL.
- */
-size_t mcl_string_length(mcl_string_s *string);
-
-/**
- * @brief Get the total allocated capacity of the string buffer.
- *
- * @param string String to query.
- * @return Capacity in bytes (including null terminator), or 0 if NULL.
- */
-size_t mcl_string_capacity(mcl_string_s *string);
-
-/**
- * @brief Get a pointer to a null-terminated C-string.
- *
- * @param string String to read.
- * @return Pointer to a thread-local buffer, or NULL on failure.
- *
- * @note Valid until the next call in the same thread. Do NOT free the returned pointer.
- * Do NOT call more than once this function in a print function.
- */
-char *mcl_string_cstr(mcl_string_s *string);
-
-/**
- * @brief Compare two strings.
- *
- * @param s1 First string.
- * @param s2 Second string.
- * @return -123 on failure or same as strcmp().
- */
-int mcl_string_compare(mcl_string_s *s1, mcl_string_s *s2);
-
-/**
- * @brief Convert the string to uppercase.
- *
- * @param string String to modify.
- */
-void mcl_string_toupper(mcl_string_s *string);
-
-/**
- * @brief Convert the string to lowercase.
- *
- * @param string String to modify.
- */
-void mcl_string_tolower(mcl_string_s *string);
-
-#endif /* MYCLIB_STRING_H */
+#ifndef MYCLIB_STRING_H
+#define MYCLIB_STRING_H
+
+#include <stddef.h>
+#include <threads.h>
+
+/**
+ * @brief Thread-safe dynamic string structure.
+ */
+typedef struct mcl_string {
+	char *data;		 /**< Pointer to null-terminated string data */
+	size_t size;	 /**< Current length (excluding null terminator) */
+	size_t capacity; /**< Allocated capacity including null terminator */
+	mtx_t lock;		 /**< Mutex for thread safety */
+} mcl_string_s;
+
+/**
+ * @brief Create a new string initialized with the given text.
+ *
+ * @param text Initial text.
+ * @param initial_capacity Initial buffer capacity (including null terminator). Pass 0 to auto-calculate.
+ * @return Pointer to the new string, or NULL on failure.
+ */
+mcl_string_s *mcl_string_new(const char *text, size_t initial_capacity);
+
+/**
+ * @brief Free the string and its resources.
+ *
+ * @param string String to free (safe to call with NULL).
+ */
+void mcl_string_free(mcl_string_s *string);
+
+/**
+ * @brief Append text to the string.
+ *
+ * @param string String to modify.
+ * @param text Text to append.
+ * @return 0 on success, -1 on failure.
+ */
+int mcl_string_append(mcl_string_s *string, const char *text);
+
+/**
+ * @brief Extend by adding another string.
+ *
+ * @param destination Destination string.
+ * @param source Source string.
+ * @return 0 on success, -1 on failure.
+ */
+int mcl_string_extend(mcl_string_s *destination, mcl_string_s *source);
+
+/**
+ * @brief Clear the string content without freeing the memory.
+ *
+ * @param string String to clear.
+ */
+void mcl_string_clear(mcl_string_s *string);
+
+/**
+ * @brief Get the current length of the string.
+ *
+ * @param string String to query.
+ * @return Length excluding null terminator, or 0 if NULL.
+ */
+size_t mcl_string_length(mcl_string_s *string);
+
+/**
+ * @brief Get the total allocated capacity of the string buffer.
+ *
+ * @param string String to query.
+ * @return Capacity in bytes (including null terminator), or 0 if NULL.
+ */
+size_t mcl_string_capacity(mcl_string_s *string);
+
+/**
+ * @brief Get a pointer to a null-terminated C-string.
+ *
+ * @param string String to read.
+ * @return Pointer to a thread-local buffer, or NULL on failure.
+ *
+ * @note Valid until the next call in the same thread. Do NOT free the returned pointer.
+ * Do NOT call more than once this function in a print function.
+ */
+char *mcl_string_cstr(mcl_string_s *string);
+
+/**
+ * @brief Compare two strings.
+ *
+ * @param s1 First string.
+ * @param s2 Second string.
+ * @return -123 on failure or same as strcmp().
+ */
+int mcl_string_compare(mcl_string_s *s1, mcl_string_s *s2);
+
+/**
+ * @brief Convert the string to uppercase.
+ *
+ * @param string String to modify.
+ */
+void mcl_string_toupper(mcl_string_s *string);
+
+/**
+ * @brief Convert the string to lowercase.
+ *
+ * @param string String to modify.
+ */
+void mcl_string_tolower(mcl_string_s *string);
+
+/**
+ * @brief Find a substring inside a string.
+ *
+ * @param string String where to search.
+ * @param substring Substring to search.
+ * @return Index of the first occurrence, -1 on failure.
+ *
+ * @note TODO
+ */
+int mcl_string_find(mcl_string_s *string, const char *substring);
+
+#endif /* MYCLIB_STRING_H */