helpers/negotiate_auth/wrapper/nw_base64.cc

   1 /*
   2  * Markus Moeller has modified the following code from Squid
   3  */
   4 #include "config.h"
   5 #include "nw_base64.h"
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9
  10
  11 static void nw_base64_init(void);
  12
  13 static int base64_initialized = 0;
  14 #define BASE64_VALUE_SZ 256
  15 int base64_value[BASE64_VALUE_SZ];
  16 const char base64_code[] =
  17     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  18
  19
  20 static void
  21 nw_base64_init(void)
  22 {
  23     int i;
  24
  25     for (i = 0; i < BASE64_VALUE_SZ; i++)
  26         base64_value[i] = -1;
  27
  28     for (i = 0; i < 64; i++)
  29         base64_value[(int) base64_code[i]] = i;
  30     base64_value[(int)'='] = 0;
  31
  32     base64_initialized = 1;
  33 }
  34
  35 void
  36 nw_base64_decode(char *result, const char *data, int result_size)
  37 {
  38     int j;
  39     int c;
  40     long val;
  41     if (!data)
  42         return;
  43     if (!base64_initialized)
  44         nw_base64_init();
  45     val = c = 0;
  46
  47     for (j = 0; *data; data++) {
  48         unsigned int k = ((unsigned char) *data) % BASE64_VALUE_SZ;
  49         if (base64_value[k] < 0)
  50             continue;
  51         val <<= 6;
  52         val += base64_value[k];
  53         if (++c < 4)
  54             continue;
  55         /* One quantum of four encoding characters/24 bit */
  56         if (j >= result_size)
  57             break;
  58         result[j++] = val >> 16;        /* High 8 bits */
  59         if (j >= result_size)
  60             break;
  61         result[j++] = (val >> 8) & 0xff;        /* Mid 8 bits */
  62         if (j >= result_size)
  63             break;
  64         result[j++] = val & 0xff;       /* Low 8 bits */
  65         val = c = 0;
  66     }
  67     return;
  68 }
  69
  70 int
  71 nw_base64_decode_len(const char *data)
  72 {
  73     int i, j;
  74
  75     j = 0;
  76     for (i = strlen(data) - 1; i >= 0; i--) {
  77         if (data[i] == '=')
  78             j++;
  79         if (data[i] != '=')
  80             break;
  81     }
  82     return strlen(data) / 4 * 3 - j;
  83 }