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/* (C) 2012 Peter Conrad <conrad@quisquis.de>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* 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 <http://www.gnu.org/licenses/>.
*/
#include "base32hex.h"
#define to_32hex(c) ((c) < 10 ? (c) + '0' : (c) + 'a' - 10)
/* out must point to a buffer of at least (len * 8 / 5) + 1 bytes.
* Encoded string is *not* padded.
* See RFC-4648. This implementation produces lowercase hex characters.
* Returns length of encoded string.
*/
unsigned int base32hex(char *out, uint8_t *in, unsigned int len) {
int buf = 0, bits = 0;
char *x = out;
while (len-- > 0) {
buf <<= 8;
buf |= *in++;
bits += 8;
while (bits >= 5) {
char c = (buf >> (bits - 5)) & 0x1f;
*x++ = to_32hex(c);
bits -= 5;
}
}
if (bits > 0) {
char c = (buf << (5 - bits)) & 0x1f;
*x++ = to_32hex(c);
}
return x - out;
}
#ifdef TEST
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static void test(char *in, char *expected, int explen) {
char buf[255];
int r;
if ((r = base32hex(buf, in, strlen(in))) != explen) {
printf("Failed: b32h('%s') yields %d chars (expected %d)\n",
in, r, explen);
exit(1);
}
if (strncmp(buf, expected, r)) {
buf[r] = 0;
printf("Failed: b32h('%s') = '%s' (expected %s)\n",
in, buf, expected);
exit(1);
}
}
int main(int argc, char **argv) {
test("", "", 0);
test("f", "co", 2);
test("fo", "cpng", 4);
test("foo", "cpnmu", 5);
test("foob", "cpnmuog", 7);
test("fooba", "cpnmuoj1", 8);
test("foobar", "cpnmuoj1e8", 10);
printf("Success!\n");
}
#endif
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