src/lib/hexstrtobin.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <ctype.h>
   4 #include <lib.h>
   5
   6 size_t hexstrtobin(const char *str, uint8_t *buf, size_t len)
   7 {
   8         size_t count, ptr = 0;
   9         uint8_t byte;
  10
  11         for (byte = count = 0; str && *str; str++) {
  12                 uint8_t c = *str;
  13
  14                 if (!isxdigit(c))
  15                         continue;
  16                 if (isdigit(c))
  17                         c -= '0';
  18                 else
  19                         c = tolower(c) - 'a' + 10;
  20
  21                 byte <<= 4;
  22                 byte |= c;
  23
  24                 if (++count > 1) {
  25                         if (ptr >= len)
  26                                 return ptr;
  27                         buf[ptr++] = byte;
  28                         byte = count = 0;
  29                 }
  30         }
  31
  32         return ptr;
  33 }