1 /* 2 * Copyright (c) 1995-2001 Kungliga Tekniska H�gskolan 3 * (Royal Institute of Technology, Stockholm, Sweden). 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * 3. Neither the name of the Institute nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifdef HAVE_CONFIG_H 35 #include <config.h> 36 RCSID("$Id: base64.c,v 1.5 2001/05/28 17:33:41 joda Exp $"); 37 #endif 38 #include <stdlib.h> 39 #include <string.h> 40 #include "base64.h" 41 42 static char base64_chars[] = 43 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 44 45 static int 46 pos(char c) 47 { 48 char *p; 49 for (p = base64_chars; *p; p++) 50 if (*p == c) 51 return p - base64_chars; 52 return -1; 53 } 54 55 int 56 base64_encode(const void *data, int size, char **str) 57 { 58 char *s, *p; 59 int i; 60 int c; 61 const unsigned char *q; 62 63 p = s = (char *) malloc(size * 4 / 3 + 4); 64 if (p == NULL) 65 return -1; 66 q = (const unsigned char *) data; 67 i = 0; 68 for (i = 0; i < size;) { 69 c = q[i++]; 70 c *= 256; 71 if (i < size) 72 c += q[i]; 73 i++; 74 c *= 256; 75 if (i < size) 76 c += q[i]; 77 i++; 78 p[0] = base64_chars[(c & 0x00fc0000) >> 18]; 79 p[1] = base64_chars[(c & 0x0003f000) >> 12]; 80 p[2] = base64_chars[(c & 0x00000fc0) >> 6]; 81 p[3] = base64_chars[(c & 0x0000003f) >> 0]; 82 if (i > size) 83 p[3] = '='; 84 if (i > size + 1) 85 p[2] = '='; 86 p += 4; 87 } 88 *p = 0; 89 *str = s; 90 return strlen(s); 91 } 92 93 #define DECODE_ERROR 0xffffffff 94 95 static unsigned int 96 token_decode(const char *token) 97 { 98 int i; 99 unsigned int val = 0; 100 int marker = 0; 101 if (strlen(token) < 4) 102 return DECODE_ERROR; 103 for (i = 0; i < 4; i++) { 104 val *= 64; 105 if (token[i] == '=') 106 marker++; 107 else if (marker > 0) 108 return DECODE_ERROR; 109 else 110 val += pos(token[i]); 111 } 112 if (marker > 2) 113 return DECODE_ERROR; 114 return (marker << 24) | val; 115 } 116 117 int 118 base64_decode(const char *str, void *data) 119 { 120 const char *p; 121 unsigned char *q; 122 123 q = data; 124 for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4) { 125 unsigned int val = token_decode(p); 126 unsigned int marker = (val >> 24) & 0xff; 127 if (val == DECODE_ERROR) 128 return -1; 129 *q++ = (val >> 16) & 0xff; 130 if (marker < 2) 131 *q++ = (val >> 8) & 0xff; 132 if (marker < 1) 133 *q++ = val & 0xff; 134 } 135 return q - (unsigned char *) data; 136 } 137