137 lines
3.6 KiB
C
137 lines
3.6 KiB
C
/*
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* Copyright (c) 1995-2001 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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RCSID("$Id: base64.c,v 1.5 2001/05/28 17:33:41 joda Exp $");
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include "base64.h"
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static char base64_chars[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static int
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pos(char c)
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{
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char *p;
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for (p = base64_chars; *p; p++)
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if (*p == c)
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return p - base64_chars;
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return -1;
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}
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int
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base64_encode(const void *data, int size, char **str)
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{
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char *s, *p;
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int i;
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int c;
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const unsigned char *q;
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p = s = (char *) malloc(size * 4 / 3 + 4);
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if (p == NULL)
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return -1;
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q = (const unsigned char *) data;
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i = 0;
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for (i = 0; i < size;) {
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c = q[i++];
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c *= 256;
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if (i < size)
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c += q[i];
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i++;
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c *= 256;
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if (i < size)
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c += q[i];
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i++;
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p[0] = base64_chars[(c & 0x00fc0000) >> 18];
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p[1] = base64_chars[(c & 0x0003f000) >> 12];
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p[2] = base64_chars[(c & 0x00000fc0) >> 6];
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p[3] = base64_chars[(c & 0x0000003f) >> 0];
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if (i > size)
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p[3] = '=';
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if (i > size + 1)
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p[2] = '=';
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p += 4;
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}
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*p = 0;
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*str = s;
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return strlen(s);
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}
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#define DECODE_ERROR 0xffffffff
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static unsigned int
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token_decode(const char *token)
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{
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int i;
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unsigned int val = 0;
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int marker = 0;
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if (strlen(token) < 4)
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return DECODE_ERROR;
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for (i = 0; i < 4; i++) {
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val *= 64;
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if (token[i] == '=')
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marker++;
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else if (marker > 0)
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return DECODE_ERROR;
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else
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val += pos(token[i]);
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}
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if (marker > 2)
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return DECODE_ERROR;
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return (marker << 24) | val;
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}
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int
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base64_decode(const char *str, void *data)
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{
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const char *p;
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unsigned char *q;
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q = data;
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for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4) {
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unsigned int val = token_decode(p);
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unsigned int marker = (val >> 24) & 0xff;
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if (val == DECODE_ERROR)
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return -1;
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*q++ = (val >> 16) & 0xff;
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if (marker < 2)
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*q++ = (val >> 8) & 0xff;
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if (marker < 1)
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*q++ = val & 0xff;
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}
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return q - (unsigned char *) data;
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}
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