Function AR_LEFT

src/arithmetic/string_funcs/string_funcs.c:26–56

returns a string containing the specified number of leftmost characters of the original string.

// returns a string containing the specified number of leftmost characters of the original string.
SIValue AR_LEFT(SIValue *argv, int argc, void *private_data) {
	if(SIValue_IsNull(argv[0])) return SI_NullVal();
	
	int64_t newlen = -1;
	if(SI_TYPE(argv[1]) == T_INT64) {
		newlen = argv[1].longval;
	} 
	if(newlen < 0) {
		ErrorCtx_SetError("length must be a non-negative integer");
		return SI_NullVal();
	}

	if(strlen(argv[0].stringval) <= newlen) {
		// No need to truncate this string based on the requested length
		return SI_DuplicateStringVal(argv[0].stringval);
	}

	// determine new string byte size
	utf8proc_int32_t c;
	int64_t newlen_bytes = 0;
	const char *str = argv[0].stringval;
	for (int i = 0; i < newlen; i++) {
		newlen_bytes += utf8proc_iterate((const utf8proc_uint8_t *)(str+newlen_bytes), -1, &c);
	}

	char *left_str = rm_malloc((newlen_bytes + 1) * sizeof(char));
 	strncpy(left_str, str, newlen_bytes * sizeof(char));
 	left_str[newlen_bytes] = '\0';

	return SI_TransferStringVal(left_str);
}

// returns the original string with leading whitespace removed.
SIValue AR_LTRIM(SIValue *argv, int argc, void *private_data) {