third_party/modp_b64/modp_b64.cc

   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 &copy; 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
  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 */
 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
 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     const uint8_t* y = (uint8_t*)src;
 215     for (i = 0; i < chunks; ++i, y += 4) {
 216         x = d0[y[0]] | d1[y[1]] | d2[y[2]] | d3[y[3]];
 217         if (x >= BADCHAR) return MODP_B64_ERROR;
 218         *p++ =  ((uint8_t*)(&x))[0];
 219         *p++ =  ((uint8_t*)(&x))[1];
 220         *p++ =  ((uint8_t*)(&x))[2];
 221     }
 222
 223     switch (leftover) {
 224     case 0:
 225         x = d0[y[0]] | d1[y[1]] | d2[y[2]] | d3[y[3]];
 226
 227         if (x >= BADCHAR) return MODP_B64_ERROR;
 228         *p++ =  ((uint8_t*)(&x))[0];
 229         *p++ =  ((uint8_t*)(&x))[1];
 230         *p =    ((uint8_t*)(&x))[2];
 231         return (chunks+1)*3;
 232         break;
 233     case 1:  /* with padding this is an impossible case */
 234         x = d0[y[0]];
 235         *p = *((uint8_t*)(&x)); // i.e. first char/byte in int
 236         break;
 237     case 2: // * case 2, 1  output byte */
 238         x = d0[y[0]] | d1[y[1]];
 239         *p = *((uint8_t*)(&x)); // i.e. first char
 240         break;
 241     default: /* case 3, 2 output bytes */
 242         x = d0[y[0]] | d1[y[1]] | d2[y[2]];  /* 0x3c */
 243         *p++ =  ((uint8_t*)(&x))[0];
 244         *p =  ((uint8_t*)(&x))[1];
 245         break;
 246     }
 247
 248     if (x >= BADCHAR) return MODP_B64_ERROR;
 249
 250     return 3*chunks + (6*leftover)/8;
 251 }
 252
 253 #endif  /* if bigendian / else / endif */