coupserv/utils.c

// My string-related utils library for now
//
// Written by: Test_User <hax@andrewyu.org>
//
// This is free and unencumbered software released into the public
// domain.
//
// Anyone is free to copy, modify, publish, use, compile, sell, or
// distribute this software, either in source code form or as a compiled
// binary, for any purpose, commercial or non-commercial, and by any
// means.
//
// In jurisdictions that recognize copyright laws, the author or authors
// of this software dedicate any and all copyright interest in the
// software to the public domain. We make this dedication for the benefit
// of the public at large and to the detriment of our heirs and
// successors. We intend this dedication to be an overt act of
// relinquishment in perpetuity of all present and future rights to this
// software under copyright law.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.

#include <stdint.h>

#include "types.h"

uint64_t str_to_unsigned(struct string str, char *err) {
	if (str.len == 0) {
		*err = 1;
		return 0;
	}

	uint64_t val = 0;
	while (str.len > 0) {
		switch(str.data[0]) {
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
			if (val > ((uint64_t)-1)/10) {
				*err = 1;
				return 0;
			}
			val *= 10;
			if (val > (-((uint64_t)((uint8_t)str.data[0] - 0x30) + 1))) {
				*err = 1;
				return 0;
			}
			val += (uint8_t)str.data[0] - 0x30;
			break;
		default:
			*err = 1;
			return 0;
		}

		str.data++;
		str.len--;
	}

	*err = 0;
	return val;
}