1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 4 -*- */
2 /* vi: set expandtab shiftwidth=4 tabstop=4: */
3 /**
4 * \file
5 * <PRE>
6 * MODP_B64 - High performance base64 encoder/decoder
7 * Version 1.3 -- 17-Mar-2006
8 * http://modp.com/release/base64
9 *
10 * Copyright © 2005, 2006 Nick Galbreath -- nickg [at] modp [dot] com
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions are
15 * met:
16 *
17 * Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * Neither the name of the modp.com nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * This is the standard "new" BSD license:
41 * http://www.opensource.org/licenses/bsd-license.php
42 * </PRE>
43 */
44
45 /* public header */
46 #include "modp_b64.h"
47
48 #include <build/build_config.h>
49
50 #undef WORDS_BIGENDIAN
51 #if !defined(ARCH_CPU_LITTLE_ENDIAN)
52 #define WORDS_BIGENDIAN 1
53 #endif
54
55 #include "modp_b64_data.h"
56
57 #define BADCHAR 0x01FFFFFF
58
59 /**
60 * you can control if we use padding by commenting out this
61 * next line. However, I highly recommend you use padding and not
62 * using it should only be for compatability with a 3rd party.
63 * Also, 'no padding' is not tested!
64 */
65 #define DOPAD 1
66
67 /*
68 * if we aren't doing padding
69 * set the pad character to NULL
70 */
71 #ifndef DOPAD
72 #undef CHARPAD
73 #define CHARPAD '\0'
74 #endif
75
modp_b64_encode(char * dest,const char * str,size_t len)76 size_t modp_b64_encode(char* dest, const char* str, size_t len)
77 {
78 size_t i = 0;
79 uint8_t* p = (uint8_t*) dest;
80
81 /* unsigned here is important! */
82 uint8_t t1, t2, t3;
83
84 if (len > 2) {
85 for (; i < len - 2; i += 3) {
86 t1 = str[i]; t2 = str[i+1]; t3 = str[i+2];
87 *p++ = e0[t1];
88 *p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
89 *p++ = e1[((t2 & 0x0F) << 2) | ((t3 >> 6) & 0x03)];
90 *p++ = e2[t3];
91 }
92 }
93
94 switch (len - i) {
95 case 0:
96 break;
97 case 1:
98 t1 = str[i];
99 *p++ = e0[t1];
100 *p++ = e1[(t1 & 0x03) << 4];
101 *p++ = CHARPAD;
102 *p++ = CHARPAD;
103 break;
104 default: /* case 2 */
105 t1 = str[i]; t2 = str[i+1];
106 *p++ = e0[t1];
107 *p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
108 *p++ = e2[(t2 & 0x0F) << 2];
109 *p++ = CHARPAD;
110 }
111
112 *p = '\0';
113 return p - (uint8_t*)dest;
114 }
115
116 #ifdef WORDS_BIGENDIAN /* BIG ENDIAN -- SUN / IBM / MOTOROLA */
modp_b64_decode(char * dest,const char * src,size_t len)117 size_t modp_b64_decode(char* dest, const char* src, size_t len)
118 {
119 if (len == 0) return 0;
120
121 #ifdef DOPAD
122 /* if padding is used, then the message must be at least
123 4 chars and be a multiple of 4.
124 there can be at most 2 pad chars at the end */
125 if (len < 4 || (len % 4 != 0)) return MODP_B64_ERROR;
126 if (src[len-1] == CHARPAD) {
127 len--;
128 if (src[len -1] == CHARPAD) {
129 len--;
130 }
131 }
132 #endif /* DOPAD */
133
134 size_t i;
135 int leftover = len % 4;
136 size_t chunks = (leftover == 0) ? len / 4 - 1 : len /4;
137
138 uint8_t* p = (uint8_t*) dest;
139 uint32_t x = 0;
140 uint32_t* destInt = (uint32_t*) p;
141 uint32_t* srcInt = (uint32_t*) src;
142 uint32_t y = *srcInt++;
143 for (i = 0; i < chunks; ++i) {
144 x = d0[y >> 24 & 0xff] | d1[y >> 16 & 0xff] |
145 d2[y >> 8 & 0xff] | d3[y & 0xff];
146
147 if (x >= BADCHAR) return MODP_B64_ERROR;
148 *destInt = x << 8;
149 p += 3;
150 destInt = (uint32_t*)p;
151 y = *srcInt++;
152 }
153
154 switch (leftover) {
155 case 0:
156 x = d0[y >> 24 & 0xff] | d1[y >> 16 & 0xff] |
157 d2[y >> 8 & 0xff] | d3[y & 0xff];
158 if (x >= BADCHAR) return MODP_B64_ERROR;
159 *p++ = ((uint8_t*)&x)[1];
160 *p++ = ((uint8_t*)&x)[2];
161 *p = ((uint8_t*)&x)[3];
162 return (chunks+1)*3;
163 case 1:
164 x = d3[y >> 24];
165 *p = (uint8_t)x;
166 break;
167 case 2:
168 x = d3[y >> 24] *64 + d3[(y >> 16) & 0xff];
169 *p = (uint8_t)(x >> 4);
170 break;
171 default: /* case 3 */
172 x = (d3[y >> 24] *64 + d3[(y >> 16) & 0xff])*64 +
173 d3[(y >> 8) & 0xff];
174 *p++ = (uint8_t) (x >> 10);
175 *p = (uint8_t) (x >> 2);
176 break;
177 }
178
179 if (x >= BADCHAR) return MODP_B64_ERROR;
180 return 3*chunks + (6*leftover)/8;
181 }
182
183 #else /* LITTLE ENDIAN -- INTEL AND FRIENDS */
184
modp_b64_decode(char * dest,const char * src,size_t len)185 size_t modp_b64_decode(char* dest, const char* src, size_t len)
186 {
187 if (len == 0) return 0;
188
189 #ifdef DOPAD
190 /*
191 * if padding is used, then the message must be at least
192 * 4 chars and be a multiple of 4
193 */
194 if (len < 4 || (len % 4 != 0)) return MODP_B64_ERROR; /* error */
195 /* there can be at most 2 pad chars at the end */
196 if (src[len-1] == CHARPAD) {
197 len--;
198 if (src[len -1] == CHARPAD) {
199 len--;
200 }
201 }
202 #endif
203
204 size_t i;
205 int leftover = len % 4;
206 size_t chunks = (leftover == 0) ? len / 4 - 1 : len /4;
207
208 uint8_t* p = (uint8_t*)dest;
209 uint32_t x = 0;
210 const uint8_t* y = (uint8_t*)src;
211 for (i = 0; i < chunks; ++i, y += 4) {
212 x = d0[y[0]] | d1[y[1]] | d2[y[2]] | d3[y[3]];
213 if (x >= BADCHAR) return MODP_B64_ERROR;
214 *p++ = ((uint8_t*)(&x))[0];
215 *p++ = ((uint8_t*)(&x))[1];
216 *p++ = ((uint8_t*)(&x))[2];
217 }
218
219 switch (leftover) {
220 case 0:
221 x = d0[y[0]] | d1[y[1]] | d2[y[2]] | d3[y[3]];
222
223 if (x >= BADCHAR) return MODP_B64_ERROR;
224 *p++ = ((uint8_t*)(&x))[0];
225 *p++ = ((uint8_t*)(&x))[1];
226 *p = ((uint8_t*)(&x))[2];
227 return (chunks+1)*3;
228 break;
229 case 1: /* with padding this is an impossible case */
230 x = d0[y[0]];
231 *p = *((uint8_t*)(&x)); // i.e. first char/byte in int
232 break;
233 case 2: // * case 2, 1 output byte */
234 x = d0[y[0]] | d1[y[1]];
235 *p = *((uint8_t*)(&x)); // i.e. first char
236 break;
237 default: /* case 3, 2 output bytes */
238 x = d0[y[0]] | d1[y[1]] | d2[y[2]]; /* 0x3c */
239 *p++ = ((uint8_t*)(&x))[0];
240 *p = ((uint8_t*)(&x))[1];
241 break;
242 }
243
244 if (x >= BADCHAR) return MODP_B64_ERROR;
245
246 return 3*chunks + (6*leftover)/8;
247 }
248
249 #endif /* if bigendian / else / endif */
250