utils.c

   1 // My string-related utils library for now
   2 //
   3 // Written by: Test_User <hax@andrewyu.org>
   4 //
   5 // This is free and unencumbered software released into the public
   6 // domain.
   7 //
   8 // Anyone is free to copy, modify, publish, use, compile, sell, or
   9 // distribute this software, either in source code form or as a compiled
  10 // binary, for any purpose, commercial or non-commercial, and by any
  11 // means.
  12 //
  13 // In jurisdictions that recognize copyright laws, the author or authors
  14 // of this software dedicate any and all copyright interest in the
  15 // software to the public domain. We make this dedication for the benefit
  16 // of the public at large and to the detriment of our heirs and
  17 // successors. We intend this dedication to be an overt act of
  18 // relinquishment in perpetuity of all present and future rights to this
  19 // software under copyright law.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  24 // IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  25 // OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  26 // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  27 // OTHER DEALINGS IN THE SOFTWARE.
  28
  29 #include <stdint.h>
  30
  31 #include "types.h"
  32
  33 uint64_t str_to_unsigned(struct string str, char *err) {
  34         if (str.len == 0) {
  35                 *err = 1;
  36                 return 0;
  37         }
  38
  39         uint64_t val = 0;
  40         while (str.len > 0) {
  41                 switch(str.data[0]) {
  42                 case '0':
  43                 case '1':
  44                 case '2':
  45                 case '3':
  46                 case '4':
  47                 case '5':
  48                 case '6':
  49                 case '7':
  50                 case '8':
  51                 case '9':
  52                         if (val > ((uint64_t)-1)/10) {
  53                                 *err = 1;
  54                                 return 0;
  55                         }
  56                         val *= 10;
  57                         if (val > (-((uint64_t)((uint8_t)str.data[0] - 0x30) + 1))) {
  58                                 *err = 1;
  59                                 return 0;
  60                         }
  61                         val += (uint8_t)str.data[0] - 0x30;
  62                         break;
  63                 default:
  64                         *err = 1;
  65                         return 0;
  66                 }
  67
  68                 str.data++;
  69                 str.len--;
  70         }
  71
  72         *err = 0;
  73         return val;
  74 }