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/* 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 2 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, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02110-1301, USA.
*
* Adapted from code written by Eric S. Raymond <esr@snark.thyrsus.com>
*
*/
/* Pair of functions to convert to/from base64.
* Also can be used to build a standalone utility and a loopback test.
* see http://www.faqs.org/rfcs/rfc3548.html
*/
/** \file base64.c
\brief Pair of functions to convert to/from base64.
*/
#include <ctype.h>
#include "base64.h"
static const char base64digits[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
#define BAD (-1)
static const char base64val[] = {
BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD,
BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD,
BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD, 62, BAD,BAD,BAD, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61,BAD,BAD, BAD,BAD,BAD,BAD,
BAD, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,BAD, BAD,BAD,BAD,BAD,
BAD, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,BAD, BAD,BAD,BAD,BAD
};
#define DECODE64(c) (isascii(c) ? base64val[c] : BAD)
/* convert inlen raw bytes at in to base64 string (NUL-terminated) at out.
* out size should be at least 4*inlen/3 + 4.
* return length of out (sans trailing NUL).
*/
int
to64frombits(unsigned char *out, const unsigned char *in, int inlen)
{
unsigned char *out0 = out;
for (; inlen >= 3; inlen -= 3)
{
*out++ = base64digits[in[0] >> 2];
*out++ = base64digits[((in[0] << 4) & 0x30) | (in[1] >> 4)];
*out++ = base64digits[((in[1] << 2) & 0x3c) | (in[2] >> 6)];
*out++ = base64digits[in[2] & 0x3f];
in += 3;
}
if (inlen > 0)
{
unsigned char fragment;
*out++ = base64digits[in[0] >> 2];
fragment = (in[0] << 4) & 0x30;
if (inlen > 1)
fragment |= in[1] >> 4;
*out++ = base64digits[fragment];
*out++ = (inlen < 2) ? '=' : base64digits[(in[1] << 2) & 0x3c];
*out++ = '=';
}
*out = '\0';
return (out-out0);
}
/* convert base64 at in to raw bytes out, returning count or <0 on error.
* base64 may contain any embedded whitespace.
* out should be at least 3/4 the length of in.
*/
int
from64tobits(char *out, const char *in)
{
int len = 0;
register unsigned char digit1, digit2, digit3, digit4;
do {
do {digit1 = *in++;} while (isspace(digit1));
if (DECODE64(digit1) == BAD)
return(-1);
do {digit2 = *in++;} while (isspace(digit2));
if (DECODE64(digit2) == BAD)
return(-2);
do {digit3 = *in++;} while (isspace(digit3));
if (digit3 != '=' && DECODE64(digit3) == BAD)
return(-3);
do {digit4 = *in++;} while (isspace(digit4));
if (digit4 != '=' && DECODE64(digit4) == BAD)
return(-4);
*out++ = (DECODE64(digit1) << 2) | (DECODE64(digit2) >> 4);
++len;
if (digit3 != '=')
{
*out++ = ((DECODE64(digit2) << 4) & 0xf0) | (DECODE64(digit3) >> 2);
++len;
if (digit4 != '=')
{
*out++ = ((DECODE64(digit3) << 6) & 0xc0) | DECODE64(digit4);
++len;
}
}
while (isspace(*in))
in++;
} while (*in && digit4 != '=');
return (len);
}
#ifdef BASE64_PROGRAM
/* standalone program that converts to/from base64.
* cc -o base64 -DBASE64_PROGRAM base64.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static void
usage (char *me)
{
fprintf (stderr, "Purpose: convert stdin to/from base64 on stdout\n");
fprintf (stderr, "Usage: %s {-t,-f}\n", me);
exit (1);
}
int
main (int ac, char *av[])
{
int to64 = 1;
/* decide whether to or from base64 */
if (ac == 2 && strcmp (av[1], "-f") == 0)
to64 = 0;
else if (ac != 1 && (ac != 2 || strcmp (av[1], "-t")))
usage (av[0]);
if (to64) {
unsigned char *rawin, *b64;
int i, n, nrawin, nb64;
/* read raw on stdin until EOF */
rawin = malloc(4096);
nrawin = 0;
while ((n = fread (rawin+nrawin, 1, 4096, stdin)) > 0)
rawin = realloc (rawin, (nrawin+=n)+4096);
/* convert to base64 */
b64 = malloc (4*nrawin/3+4);
nb64 = to64frombits(b64, rawin, nrawin);
/* pretty print */
for (i = 0; i < nb64; i += 72)
printf ("%.*s\n", 72, b64+i);
} else {
unsigned char *raw, *b64;
int n, nraw, nb64;
/* read base64 on stdin until EOF */
b64 = malloc(4096);
nb64 = 0;
while ((n = fread (b64+nb64, 1, 4096, stdin)) > 0)
b64 = realloc (b64, (nb64+=n)+4096);
b64[nb64] = '\0';
/* convert to raw */
raw = malloc (3*nb64/4);
nraw = from64tobits(raw, b64);
if (nraw < 0) {
fprintf (stderr, "base64 conversion error: %d\n", nraw);
return (1);
}
/* write */
fwrite (raw, 1, nraw, stdout);
}
return (0);
}
#endif
#ifdef LOOPBACK_TEST
/* standalone test that reads binary on stdin, converts to base64 and back,
* then compares. exit 0 if compares the same else 1
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int
main (int ac, char *av[])
{
unsigned char *rawin, *b64, *rawback;
int n, nrawin, nrawback, nb64;
/* read raw on stdin until EOF */
rawin = malloc(4096);
nrawin = 0;
while ((n = fread (rawin+nrawin, 1, 4096, stdin)) > 0)
rawin = realloc (rawin, (nrawin+=n)+4096);
/* convert to base64 */
b64 = malloc (4*nrawin*3 + 4);
nb64 = to64frombits(b64, rawin, nrawin);
/* convert back to raw */
rawback = malloc (3*nb64/4);
nrawback = from64tobits(rawback, b64);
if (nrawback < 0) {
fprintf (stderr, "base64 error: %d\n", nrawback);
return(1);
}
if (nrawback != nrawin) {
fprintf (stderr, "base64 back length %d != %d\n", nrawback, nrawin);
return(1);
}
/* compare */
if (memcmp (rawback, rawin, nrawin)) {
fprintf (stderr, "compare error\n");
return (1);
}
/* success */
return (0);
}
#endif
/* For RCS Only -- Do Not Edit */
static char *rcsid[2] = {(char *)rcsid, "@(#) $RCSfile$ $Date$ $Revision$ $Name: $"};
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