/*
* Helper functions for test programs.
* Copyright © 2012 Nick Bowler
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
#include
#include
#include "common.h"
/*
* Decode a hexadecimal string into a sequence of bytes. If there are an
* odd number of nibbles, treat the first character as the least significant
* nibble of the first byte. The result is written to the buffer specified by
* buf. At most n bytes are written to the buffer.
*
* Returns the number of bytes that would be written provided that n was large
* enough, or (size_t)-1 if the input is not valid.
*/
size_t test_decode_hex(const char *hex, unsigned char *buf, size_t n)
{
size_t len, count = 0;
char tmp[] = "00";
for (len = 0; hex[len]; len++) {
if (!isxdigit(hex[len]))
return -1;
}
if (!len)
return 0;
switch (len % 2) {
while (len > 0) {
case 0: tmp[0] = *hex++; len--;
case 1: tmp[1] = *hex++; len--;
if (count < n)
buf[count] = strtoul(tmp, NULL, 16);
count++;
}
}
return count;
}