lib/base64-decode.c

/*
 * This code originally came from here
 *
 * http://base64.sourceforge.net/b64.c
 *
 * with the following license:
 *
 * LICENCE:        Copyright (c) 2001 Bob Trower, Trantor Standard Systems Inc.
 *
 *                Permission is hereby granted, free of charge, to any person
 *                obtaining a copy of this software and associated
 *                documentation files (the "Software"), to deal in the
 *                Software without restriction, including without limitation
 *                the rights to use, copy, modify, merge, publish, distribute,
 *                sublicense, and/or sell copies of the Software, and to
 *                permit persons to whom the Software is furnished to do so,
 *                subject to the following conditions:
 *
 *                The above copyright notice and this permission notice shall
 *                be included in all copies or substantial portions of the
 *                Software.
 *
 *                THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
 *                KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 *                WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 *                PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
 *                OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 *                OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 *                OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 *                SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * VERSION HISTORY:
 *               Bob Trower 08/04/01 -- Create Version 0.00.00B
 *
 * I cleaned it up quite a bit to match the (linux kernel) style of the rest
 * of libwebsockets; this version is under LGPL2 like the rest of libwebsockets
 * since he explictly allows sublicensing, but I give the URL above so you can
 * get the original with Bob's super-liberal terms directly if you prefer.
 */


#include <stdio.h>
#include <string.h>
#include "private-libwebsockets.h"

static const char encode[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
			     "abcdefghijklmnopqrstuvwxyz0123456789+/";
static const char decode[] = "|$$$}rstuvwxyz{$$$$$$$>?@ABCDEFGHIJKLMNOPQRSTUVW"
			     "$$$$$$XYZ[\\]^_`abcdefghijklmnopq";

LWS_VISIBLE int
lws_b64_encode_string(const char *in, int in_len, char *out, int out_size)
{
	unsigned char triple[3];
	int i;
	int len;
	int line = 0;
	int done = 0;

	while (in_len) {
		len = 0;
		for (i = 0; i < 3; i++) {
			if (in_len) {
				triple[i] = *in++;
				len++;
				in_len--;
			} else
				triple[i] = 0;
		}
		if (!len)
			continue;

		if (done + 4 >= out_size)
			return -1;

		*out++ = encode[triple[0] >> 2];
		*out++ = encode[((triple[0] & 0x03) << 4) |
					     ((triple[1] & 0xf0) >> 4)];
		*out++ = (len > 1 ? encode[((triple[1] & 0x0f) << 2) |
					     ((triple[2] & 0xc0) >> 6)] : '=');
		*out++ = (len > 2 ? encode[triple[2] & 0x3f] : '=');

		done += 4;
		line += 4;
	}

	if (done + 1 >= out_size)
		return -1;

	*out++ = '\0';

	return done;
}