release/src/router/shared/base64.c

   1 /*
   2
   3         Tomato Firmware
   4         Copyright (C) 2006-2009 Jonathan Zarate
   5
   6 */
   7 #include <stdio.h>
   8 #include <string.h>
   9
  10 /*
  11
  12 111111  110000  000011  111111
  13 0         1         2
  14
  15 echo -n "aaa" | uuencode -m -
  16 begin-base64 644 -
  17 YWFh
  18
  19 echo -n "a" | uuencode -m -
  20 begin-base64 644 -
  21 YQ==
  22
  23 echo -n "aa" | uuencode -m -
  24 begin-base64 644 -
  25 YWE=
  26
  27 */
  28
  29 static const char base64_xlat[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  30
  31
  32 int base64_encode(const unsigned char *in, char *out, int inlen)
  33 {
  34         char *o;
  35
  36         o = out;
  37         while (inlen >= 3) {
  38                 *out++ = base64_xlat[*in >> 2];
  39                 *out++ = base64_xlat[((*in << 4) & 0x3F) | (*(in + 1) >> 4)];
  40                 ++in;   // note: gcc complains if *(++in)
  41                 *out++ = base64_xlat[((*in << 2) & 0x3F) | (*(in + 1) >> 6)];
  42                 ++in;
  43                 *out++ = base64_xlat[*in++ & 0x3F];
  44                 inlen -= 3;
  45         }
  46         if (inlen > 0) {
  47                 *out++ = base64_xlat[*in >> 2];
  48                 if (inlen == 2) {
  49                         *out++ = base64_xlat[((*in << 4) & 0x3F) | (*(in + 1) >> 4)];
  50                         ++in;
  51                         *out++ = base64_xlat[((*in << 2) & 0x3F)];
  52                 }
  53                 else {
  54                         *out++ = base64_xlat[(*in << 4) & 0x3F];
  55                         *out++ = '=';
  56                 }
  57                 *out++ = '=';
  58         }
  59         return out - o;
  60 }
  61
  62
  63 int base64_decode(const char *in, unsigned char *out, int inlen)
  64 {
  65         char *p;
  66         int n;
  67         unsigned long x;
  68         unsigned char *o;
  69         char c;
  70
  71         o = out;
  72         n = 0;
  73         x = 0;
  74         while (inlen-- > 0) {
  75                 if (*in == '=') break;
  76                 if ((p = strchr(base64_xlat, c = *in++)) == NULL) {
  77 //                      printf("ignored - %x %c\n", c, c);
  78                         continue;       // note: invalid characters are just ignored
  79                 }
  80                 x = (x << 6) | (p - base64_xlat);
  81                 if (++n == 4) {
  82                         *out++ = x >> 16;
  83                         *out++ = (x >> 8) & 0xFF;
  84                         *out++ = x & 0xFF;
  85                         n = 0;
  86                         x = 0;
  87                 }
  88         }
  89         if (n == 3) {
  90                 *out++ = x >> 10;
  91                 *out++ = (x >> 2) & 0xFF;
  92         }
  93         else if (n == 2) {
  94                 *out++ = x >> 4;
  95         }
  96         return out - o;
  97 }
  98
  99 int base64_encoded_len(int len)
 100 {
 101         return ((len + 2) / 3) * 4;
 102 }
 103
 104 int base64_decoded_len(int len)
 105 {
 106         return ((len + 3) / 4) * 3;
 107 }
 108
 109 /*
 110 int main(int argc, char **argv)
 111 {
 112         char *test = "a";
 113         char buf[128];
 114         char buf2[128];
 115         const char *in;
 116         int len;
 117
 118         memset(buf, 0, sizeof(buf));
 119         base64_encode(test, buf, strlen(test));
 120         printf("buf=%s\n", buf);
 121
 122         memset(buf2, 0, sizeof(buf2));
 123         base64_decode(buf, buf2, base64_encoded_len(strlen(test)));
 124         printf("buf2=%s\n", buf2);
 125 }
 126 */