Function AR_REPLACE

src/arithmetic/string_funcs/string_funcs.c:576–662

returns a string in which all occurrences of a specified string in the original string have been replaced by ANOTHER (specified) string. for example: RETURN replace('Well I wish I was in the land of cotton', 'cotton', 'the free') the result is Well I wish I was in the land of the free

// for example: RETURN replace('Well I wish I was in the land of cotton', 'cotton', 'the free')
// the result is Well I wish I was in the land of the free
SIValue AR_REPLACE(SIValue *argv, int argc, void *private_data) {
	// No string contains null.
	if(SIValue_IsNull(argv[0]) ||
	   SIValue_IsNull(argv[1]) ||
	   SIValue_IsNull(argv[2])) return SI_NullVal();

	// argv[0] is the original string to be manipulated
	// argv[1] is the search sub string to be replaced
	// argv[2] is the string to be replaced with
	const char *str            =  argv[0].stringval;
	const char *old_string     =  argv[1].stringval;
	const char *new_string     =  argv[2].stringval;
	size_t      str_len        =  strlen(str);
	size_t      old_string_len =  strlen(old_string);
	size_t      new_string_len =  strlen(new_string);

	const char *ptr  = str;
	const char **arr = array_new(const char *, 0);

	// if any parameter is not a valid utf8 string return the original string
	if(!str_utf8_validate(old_string) || !str_utf8_validate(new_string) ||
		!str_utf8_validate(str)) {
		return SI_DuplicateStringVal(str);
	}

	while(ptr <= str + str_len) {
		// find pointer to next substring
		ptr = strstr(ptr, old_string);

		// if no substring found, then break from the loop
		if(ptr == NULL) break;

		// store ptr for replace use
		array_append(arr, ptr);

		// increment our string pointer in case search string is empty move one char
		ptr += old_string_len == 0 ? 1 : old_string_len;
	}

	int occurrences = array_len(arr);

	// if sub string not found return original string
	if(occurrences == 0) {
		array_free(arr);
		return SI_DuplicateStringVal(str);
	}

	// calculate new buffer size
	size_t buffer_size = strlen(str) + (occurrences * new_string_len) - (occurrences * old_string_len);

	// allocate buffer
	char *buffer = (char*) rm_malloc(sizeof(char) * buffer_size + 1);

	// set pointers to start point
	ptr = str;
	char *buffer_ptr = buffer;

	// iterate occurrences