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/*
* FILE: base64.c
* AUTHOR: Colin Perkins
*
* MIME base64 encoder/decoder described in rfc1521. This code is derived
* from version 2.7 of the Bellcore metamail package.
*
* Copyright (c) 1998 University College London
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, is permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Computer Science
* Department at University College London
* 4. Neither the name of the University nor of the Department may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Copyright (c) 1991 Bell Communications Research, Inc. (Bellcore)
*
* Permission to use, copy, modify, and distribute this material
* for any purpose and without fee is hereby granted, provided
* that the above copyright notice and this permission notice
* appear in all copies, and that the name of Bellcore not be
* used in advertising or publicity pertaining to this
* material without the specific, prior written permission
* of an authorized representative of Bellcore. BELLCORE
* MAKES NO REPRESENTATIONS ABOUT THE ACCURACY OR SUITABILITY
* OF THIS MATERIAL FOR ANY PURPOSE. IT IS PROVIDED "AS IS",
* WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES.
*
*/
#include "config_unix.h"
#include "config_win32.h"
#include "debug.h"
#include "base64.h"
static unsigned char basis_64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int base64encode(unsigned char *input, int input_length, unsigned char *output, int output_length)
{
int i = 0, j = 0;
int pad;
assert(output_length >= (input_length * 4 / 3));
while (i < input_length) {
pad = 3 - (input_length - i);
if (pad == 2) {
output[j ] = basis_64[input[i]>>2];
output[j+1] = basis_64[(input[i] & 0x03) << 4];
output[j+2] = '=';
output[j+3] = '=';
} else if (pad == 1) {
output[j ] = basis_64[input[i]>>2];
output[j+1] = basis_64[((input[i] & 0x03) << 4) | ((input[i+1] & 0xf0) >> 4)];
output[j+2] = basis_64[(input[i+1] & 0x0f) << 2];
output[j+3] = '=';
} else{
output[j ] = basis_64[input[i]>>2];
output[j+1] = basis_64[((input[i] & 0x03) << 4) | ((input[i+1] & 0xf0) >> 4)];
output[j+2] = basis_64[((input[i+1] & 0x0f) << 2) | ((input[i+2] & 0xc0) >> 6)];
output[j+3] = basis_64[input[i+2] & 0x3f];
}
i += 3;
j += 4;
}
return j;
}
/* This assumes that an unsigned char is exactly 8 bits. Not portable code! :-) */
static unsigned char index_64[128] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 62, 0xff, 0xff, 0xff, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 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, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 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, 0xff, 0xff, 0xff, 0xff, 0xff
};
#define char64(c) ((c > 127) ? 0xff : index_64[(c)])
int base64decode(unsigned char *input, int input_length, unsigned char *output, int output_length)
{
int i = 0, j = 0, pad;
unsigned char c[4];
assert(output_length >= (input_length * 3 / 4));
assert((input_length % 4) == 0);
while ((i + 3) < input_length) {
pad = 0;
c[0] = char64(input[i ]); pad += (c[0] == 0xff);
c[1] = char64(input[i+1]); pad += (c[1] == 0xff);
c[2] = char64(input[i+2]); pad += (c[2] == 0xff);
c[3] = char64(input[i+3]); pad += (c[3] == 0xff);
if (pad == 2) {
output[j++] = (c[0] << 2) | ((c[1] & 0x30) >> 4);
output[j] = (c[1] & 0x0f) << 4;
} else if (pad == 1) {
output[j++] = (c[0] << 2) | ((c[1] & 0x30) >> 4);
output[j++] = ((c[1] & 0x0f) << 4) | ((c[2] & 0x3c) >> 2);
output[j] = (c[2] & 0x03) << 6;
} else {
output[j++] = (c[0] << 2) | ((c[1] & 0x30) >> 4);
output[j++] = ((c[1] & 0x0f) << 4) | ((c[2] & 0x3c) >> 2);
output[j++] = ((c[2] & 0x03) << 6) | (c[3] & 0x3f);
}
i += 4;
}
return j;
}
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