1 /* 2 * Copyright (c) 1995-2001 Kungliga Tekniska Högskolan 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 #include <config.h> 35 36 #include <stdlib.h> 37 #include <string.h> 38 #include <limits.h> 39 #include "base64.h" 40 41 static const char base64_chars[] = 42 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 43 44 static int 45 pos(char c) 46 { 47 const char *p; 48 for (p = base64_chars; *p; p++) 49 if (*p == c) 50 return p - base64_chars; 51 return -1; 52 } 53 54 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL 55 base64_encode(const void *data, int size, char **str) 56 { 57 char *s, *p; 58 int i; 59 int c; 60 const unsigned char *q; 61 62 if (size > INT_MAX/4 || size < 0) { 63 *str = NULL; 64 return -1; 65 } 66 67 p = s = (char *) malloc(size * 4 / 3 + 4); 68 if (p == NULL) { 69 *str = NULL; 70 return -1; 71 } 72 q = (const unsigned char *) data; 73 74 for (i = 0; i < size;) { 75 c = q[i++]; 76 c *= 256; 77 if (i < size) 78 c += q[i]; 79 i++; 80 c *= 256; 81 if (i < size) 82 c += q[i]; 83 i++; 84 p[0] = base64_chars[(c & 0x00fc0000) >> 18]; 85 p[1] = base64_chars[(c & 0x0003f000) >> 12]; 86 p[2] = base64_chars[(c & 0x00000fc0) >> 6]; 87 p[3] = base64_chars[(c & 0x0000003f) >> 0]; 88 if (i > size) 89 p[3] = '='; 90 if (i > size + 1) 91 p[2] = '='; 92 p += 4; 93 } 94 *p = 0; 95 *str = s; 96 return (int) strlen(s); 97 } 98 99 #define DECODE_ERROR 0xffffffff 100 101 static unsigned int 102 token_decode(const char *token) 103 { 104 int i; 105 unsigned int val = 0; 106 int marker = 0; 107 if (strlen(token) < 4) 108 return DECODE_ERROR; 109 for (i = 0; i < 4; i++) { 110 val *= 64; 111 if (token[i] == '=') 112 marker++; 113 else if (marker > 0) 114 return DECODE_ERROR; 115 else 116 val += pos(token[i]); 117 } 118 if (marker > 2) 119 return DECODE_ERROR; 120 return (marker << 24) | val; 121 } 122 123 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL 124 base64_decode(const char *str, void *data) 125 { 126 const char *p; 127 unsigned char *q; 128 129 q = data; 130 for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4) { 131 unsigned int val = token_decode(p); 132 unsigned int marker = (val >> 24) & 0xff; 133 if (val == DECODE_ERROR) 134 return -1; 135 *q++ = (val >> 16) & 0xff; 136 if (marker < 2) 137 *q++ = (val >> 8) & 0xff; 138 if (marker < 1) 139 *q++ = val & 0xff; 140 } 141 return q - (unsigned char *) data; 142 } 143