src/cevpb64.c

   1 /*
   2
   3 cevpb64.c -- compatibility implemenation of EVP base 64 functions
   4 Copyright (c) 2014 Kyle J. McKay.  All rights reserved.
   5
   6 This program is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public License
   8 as published by the Free Software Foundation; either version 2
   9 of the License, or (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19
  20 */
  21
  22 #include <stddef.h>
  23
  24 static const signed char b64tab[256] = {
  25 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  26 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  27 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,0x3E,-1,-1,-1,0x3F,
  28 0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,-1,-1,-1,0x40,-1,-1,
  29 -1,0,1,2,3,4,5,6,7,8,9,0x0A,0x0B,0x0C,0x0D,0x0E,
  30 0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,-1,-1,-1,-1,-1,
  31 -1,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,
  32 0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,0x30,0x31,0x32,0x33,-1,-1,-1,-1,-1,
  33 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  34 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  35 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  36 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  37 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  38 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  39 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  40 -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
  41 };
  42
  43 static void decode24(const unsigned char *input, unsigned char *output)
  44 {
  45   output[0] = ((b64tab[input[0]]&0x3F)<<2)|((b64tab[input[1]]&0x3F)>>4);
  46   output[1] = (((b64tab[input[1]]&0x3F)&0x0F)<<4)|((b64tab[input[2]]&0x3F)>>2);
  47   output[2] = (((b64tab[input[2]]&0x3F)&0x03)<<6)|(b64tab[input[3]]&0x3F);
  48 }
  49
  50 static int DecodeBase64Block(const void *_in, size_t inl, void *_out, size_t *outl)
  51 {
  52   const unsigned char *in = (unsigned char *)_in;
  53   unsigned char *out = (unsigned char *)_out;
  54   unsigned char inb[4];
  55   unsigned char outb[3];
  56   size_t count;
  57   int i;
  58
  59   if (inl && !in)
  60     return -1;
  61   if (!inl) {
  62     *outl = 0;
  63     return 0;
  64   }
  65   count = 0;
  66   for (i=0; inl; ++in, --inl) {
  67     unsigned char c = *in;
  68     if (c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == '\f')
  69       continue;
  70     if (b64tab[c] < 0)
  71       return -1;
  72     inb[i++] = c;
  73     if (i == 4) {
  74       decode24(inb, outb);
  75       i = 0;
  76       if (inb[3] == '=') {
  77         *out++ = outb[0];
  78         ++count;
  79         if (inb[2] != '=') {
  80           *out++ = outb[1];
  81           ++count;
  82         }
  83         break;
  84       }
  85       *out++ = outb[0];
  86       *out++ = outb[1];
  87       *out++ = outb[2];
  88       count += 3;
  89     }
  90   }
  91   if (i != 0)
  92     return -1;
  93   *outl = count;
  94   return 0;
  95 }
  96
  97 static const char tab64[64] = {
  98 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
  99 'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
 100 'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
 101 'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'
 102 };
 103
 104 static void encode24(const unsigned char *input, unsigned char *output)
 105
 106 {
 107     output[0] = tab64[input[0]>>2];
 108     output[1] = tab64[((input[0]&0x3)<<4)+(input[1]>>4)];
 109     output[2] = tab64[((input[1]&0xF)<<2)+(input[2]>>6)];
 110     output[3] = tab64[input[2]&0x3F];
 111 }
 112
 113 static int EncodeBase64Block(const void *_in, size_t inl, void *_out, size_t *outl)
 114 {
 115   const unsigned char *in = (unsigned char *)_in;
 116   unsigned char *out = (unsigned char *)_out;
 117   size_t count;
 118   int i;
 119
 120   if (inl && !in)
 121     return -1;
 122   if (!inl) {
 123     *outl = 0;
 124     return 0;
 125   }
 126   count = 0;
 127   for (i=0; inl >= 3; in+=3, inl-=3) {
 128     encode24(in, out);
 129     out += 4;
 130     count += 4;
 131   }
 132   if (inl) {
 133     unsigned char inb[3];
 134     inb[0] = *in;
 135     inb[1] = inl == 2 ? in[1] : '\0';
 136     inb[2] = '\0';
 137     encode24(inb, out);
 138     count += 4;
 139   }
 140   *outl = count;
 141   return 0;
 142 }
 143
 144 int cEVP_DecodeBlock(void *to, const void *from, int fromlen)
 145 {
 146   int err;
 147   size_t ans;
 148
 149   if (fromlen < 0)
 150     return -1;
 151   err = DecodeBase64Block(from, (size_t)fromlen, to, &ans);
 152   if (err)
 153     return -1;
 154   return (int)ans;
 155 }
 156
 157 int cEVP_EncodeBlock(void *to, const void *from, int fromlen)
 158 {
 159   int err;
 160   size_t ans;
 161
 162   if (fromlen < 0)
 163     return -1;
 164   err = EncodeBase64Block(from, (size_t)fromlen, to, &ans);
 165   if (err)
 166     return -1;
 167   return (int)ans;
 168 }