src/lib/hexstrtobin.c

   1 /*
   2  * Copyright 2016 Google Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but without any warranty; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <lib.h>
  15 #include <string.h>
  16
  17 size_t hexstrtobin(const char *str, uint8_t *buf, size_t len)
  18 {
  19         size_t count, ptr = 0;
  20         uint8_t byte;
  21
  22         for (byte = count = 0; str && *str; str++) {
  23                 uint8_t c = *str;
  24
  25                 if (!isxdigit(c))
  26                         continue;
  27                 if (isdigit(c))
  28                         c -= '0';
  29                 else
  30                         c = tolower(c) - 'a' + 10;
  31
  32                 byte <<= 4;
  33                 byte |= c;
  34
  35                 if (++count > 1) {
  36                         if (ptr >= len)
  37                                 return ptr;
  38                         buf[ptr++] = byte;
  39                         byte = count = 0;
  40                 }
  41         }
  42
  43         return ptr;
  44 }