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
pos(char c)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
base64_encode(const void * data,int size,char ** str)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
token_decode(const char * token)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
base64_decode(const char * str,void * data)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