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 /*
49 * If you are ripping this out of the library, comment out the next
50 * line and uncomment the next lines as approrpiate
51 */
52 //#include "config.h"
53
54 /* if on motoral, sun, ibm; uncomment this */
55 /* #define WORDS_BIGENDIAN 1 */
56 /* else for Intel, Amd; uncomment this */
57 /* #undef WORDS_BIGENDIAN */
58
59 #include "modp_b64_data.h"
60
61 #define BADCHAR 0x01FFFFFF
62
63 /**
64 * you can control if we use padding by commenting out this
65 * next line. However, I highly recommend you use padding and not
66 * using it should only be for compatability with a 3rd party.
67 * Also, 'no padding' is not tested!
68 */
69 #define DOPAD 1
70
71 /*
72 * if we aren't doing padding
73 * set the pad character to NULL
74 */
75 #ifndef DOPAD
76 #undef CHARPAD
77 #define CHARPAD '\0'
78 #endif
79
modp_b64_encode(char * dest,const char * str,size_t len)80 size_t modp_b64_encode(char* dest, const char* str, size_t len)
81 {
82 size_t i = 0;
83 uint8_t* p = (uint8_t*) dest;
84
85 /* unsigned here is important! */
86 uint8_t t1, t2, t3;
87
88 if (len > 2) {
89 for (; i < len - 2; i += 3) {
90 t1 = str[i]; t2 = str[i+1]; t3 = str[i+2];
91 *p++ = e0[t1];
92 *p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
93 *p++ = e1[((t2 & 0x0F) << 2) | ((t3 >> 6) & 0x03)];
94 *p++ = e2[t3];
95 }
96 }
97
98 switch (len - i) {
99 case 0:
100 break;
101 case 1:
102 t1 = str[i];
103 *p++ = e0[t1];
104 *p++ = e1[(t1 & 0x03) << 4];
105 *p++ = CHARPAD;
106 *p++ = CHARPAD;
107 break;
108 default: /* case 2 */
109 t1 = str[i]; t2 = str[i+1];
110 *p++ = e0[t1];
111 *p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
112 *p++ = e2[(t2 & 0x0F) << 2];
113 *p++ = CHARPAD;
114 }
115
116 *p = '\0';
117 return p - (uint8_t*)dest;
118 }
119
120 #ifdef WORDS_BIGENDIAN /* BIG ENDIAN -- SUN / IBM / MOTOROLA */
modp_b64_decode(char * dest,const char * src,int len)121 int modp_b64_decode(char* dest, const char* src, int len)
122 {
123 if (len == 0) return 0;
124
125 #ifdef DOPAD
126 /* if padding is used, then the message must be at least
127 4 chars and be a multiple of 4.
128 there can be at most 2 pad chars at the end */
129 if (len < 4 || (len % 4 != 0)) return MODP_B64_ERROR;
130 if (src[len-1] == CHARPAD) {
131 len--;
132 if (src[len -1] == CHARPAD) {
133 len--;
134 }
135 }
136 #endif /* DOPAD */
137
138 size_t i;
139 int leftover = len % 4;
140 size_t chunks = (leftover == 0) ? len / 4 - 1 : len /4;
141
142 uint8_t* p = (uint8_t*) dest;
143 uint32_t x = 0;
144 uint32_t* destInt = (uint32_t*) p;
145 uint32_t* srcInt = (uint32_t*) src;
146 uint32_t y = *srcInt++;
147 for (i = 0; i < chunks; ++i) {
148 x = d0[y >> 24 & 0xff] | d1[y >> 16 & 0xff] |
149 d2[y >> 8 & 0xff] | d3[y & 0xff];
150
151 if (x >= BADCHAR) return MODP_B64_ERROR;
152 *destInt = x << 8;
153 p += 3;
154 destInt = (uint32_t*)p;
155 y = *srcInt++;
156 }
157
158 switch (leftover) {
159 case 0:
160 x = d0[y >> 24 & 0xff] | d1[y >> 16 & 0xff] |
161 d2[y >> 8 & 0xff] | d3[y & 0xff];
162 if (x >= BADCHAR) return MODP_B64_ERROR;
163 *p++ = ((uint8_t*)&x)[1];
164 *p++ = ((uint8_t*)&x)[2];
165 *p = ((uint8_t*)&x)[3];
166 return (chunks+1)*3;
167 case 1:
168 x = d3[y >> 24];
169 *p = (uint8_t)x;
170 break;
171 case 2:
172 x = d3[y >> 24] *64 + d3[(y >> 16) & 0xff];
173 *p = (uint8_t)(x >> 4);
174 break;
175 default: /* case 3 */
176 x = (d3[y >> 24] *64 + d3[(y >> 16) & 0xff])*64 +
177 d3[(y >> 8) & 0xff];
178 *p++ = (uint8_t) (x >> 10);
179 *p = (uint8_t) (x >> 2);
180 break;
181 }
182
183 if (x >= BADCHAR) return MODP_B64_ERROR;
184 return 3*chunks + (6*leftover)/8;
185 }
186
187 #else /* LITTLE ENDIAN -- INTEL AND FRIENDS */
188
modp_b64_decode(char * dest,const char * src,size_t len)189 size_t modp_b64_decode(char* dest, const char* src, size_t len)
190 {
191 if (len == 0) return 0;
192
193 #ifdef DOPAD
194 /*
195 * if padding is used, then the message must be at least
196 * 4 chars and be a multiple of 4
197 */
198 if (len < 4 || (len % 4 != 0)) return MODP_B64_ERROR; /* error */
199 /* there can be at most 2 pad chars at the end */
200 if (src[len-1] == CHARPAD) {
201 len--;
202 if (src[len -1] == CHARPAD) {
203 len--;
204 }
205 }
206 #endif
207
208 size_t i;
209 int leftover = len % 4;
210 size_t chunks = (leftover == 0) ? len / 4 - 1 : len /4;
211
212 uint8_t* p = (uint8_t*)dest;
213 uint32_t x = 0;
214 uint32_t* destInt = (uint32_t*) p;
215 uint32_t* srcInt = (uint32_t*) src;
216 uint32_t y = *srcInt++;
217 for (i = 0; i < chunks; ++i) {
218 x = d0[y & 0xff] |
219 d1[(y >> 8) & 0xff] |
220 d2[(y >> 16) & 0xff] |
221 d3[(y >> 24) & 0xff];
222
223 if (x >= BADCHAR) return MODP_B64_ERROR;
224 *destInt = x ;
225 p += 3;
226 destInt = (uint32_t*)p;
227 y = *srcInt++;}
228
229
230 switch (leftover) {
231 case 0:
232 x = d0[y & 0xff] |
233 d1[(y >> 8) & 0xff] |
234 d2[(y >> 16) & 0xff] |
235 d3[(y >> 24) & 0xff];
236
237 if (x >= BADCHAR) return MODP_B64_ERROR;
238 *p++ = ((uint8_t*)(&x))[0];
239 *p++ = ((uint8_t*)(&x))[1];
240 *p = ((uint8_t*)(&x))[2];
241 return (chunks+1)*3;
242 break;
243 case 1: /* with padding this is an impossible case */
244 x = d0[y & 0xff];
245 *p = *((uint8_t*)(&x)); // i.e. first char/byte in int
246 break;
247 case 2: // * case 2, 1 output byte */
248 x = d0[y & 0xff] | d1[y >> 8 & 0xff];
249 *p = *((uint8_t*)(&x)); // i.e. first char
250 break;
251 default: /* case 3, 2 output bytes */
252 x = d0[y & 0xff] |
253 d1[y >> 8 & 0xff ] |
254 d2[y >> 16 & 0xff]; /* 0x3c */
255 *p++ = ((uint8_t*)(&x))[0];
256 *p = ((uint8_t*)(&x))[1];
257 break;
258 }
259
260 if (x >= BADCHAR) return MODP_B64_ERROR;
261
262 return 3*chunks + (6*leftover)/8;
263 }
264
265 #endif /* if bigendian / else / endif */
266