Function string_substr

string/std_string.c:479–521

* @brief Extracts a substring from the given String object. * * This function creates a new String object containing a substring of the original string starting at the specified * position and having the specified length. If the length exceeds the bounds of the original string, * the substring will be shortened accordingly. * * @param str The original String object from which the substring

 * @return A new String object containing the substring, or NULL if an error occurs.
 */
String* string_substr(String* str, size_t pos, size_t len) {
    STRING_LOG("[string_substr]: Entering function with pos=%zu, len=%zu.\n", pos, len);

    if (str == NULL) {
        STRING_LOG("[string_substr]: Error: The String object is NULL.\n");
        return NULL;
    }
    if (pos >= str->size) {
        STRING_LOG("[string_substr]: Error: Position out of bounds (pos=%zu, size=%zu).\n", pos, str->size);
        return NULL;
    }

    // Adjust len if it goes beyond the end of the string
    if (pos + len > str->size) { 
        len = str->size - pos;
    }

    STRING_LOG("[string_substr]: Allocating memory for substring (len=%zu).\n", len);
    String* substr = string_create(NULL); 
    if (substr == NULL) {
        STRING_LOG("[string_substr]: Error: Memory allocation failed for substring.\n");
        return NULL;
    }

    if (len + 1 > substr->capacitySize) {
        char* newData = (char*)memory_pool_allocate(substr->pool, len + 1);
        if (!newData) {
            STRING_LOG("[string_substr]: Error: Pool allocation failed for dataStr.\n");
            string_deallocate(substr);
            return NULL;
        }
        substr->dataStr = newData;
        substr->capacitySize = len + 1;
    }

    STRING_LOG("[string_substr]: Copying substring from pos=%zu, len=%zu.\n", pos, len);
    memcpy(substr->dataStr, str->dataStr + pos, len);
    substr->dataStr[len] = '\0';
    substr->size = len;

    STRING_LOG("[string_substr]: Successfully created substring.\n");
    return substr;
}


/**