/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com */#include "tomcrypt.h"/**  @file base64_decode.c  Compliant base64 code donated by Wayne Scott (wscott@bitmover.com)*/#ifdef BASE64static const unsigned char map[256] = {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255,  62, 255, 255, 255,  63, 52,  53,  54,  55,  56,  57,  58,  59,  60,  61, 255, 255,255, 254, 255, 255, 255,   0,   1,   2,   3,   4,   5,   6,  7,   8,   9,  10,  11,  12,  13,  14,  15,  16,  17,  18, 19,  20,  21,  22,  23,  24,  25, 255, 255, 255, 255, 255,255,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36, 37,  38,  39,  40,  41,  42,  43,  44,  45,  46,  47,  48, 49,  50,  51, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,255, 255, 255, 255 };/**   base64 decode a block of memory   @param in       The base64 data to decode   @param inlen    The length of the base64 data   @param out      [out] The destination of the binary decoded data   @param outlen   [in/out] The max size and resulting size of the decoded data   @return CRYPT_OK if successful*/int base64_decode(const unsigned char *in,  unsigned long inlen,                         unsigned char *out, unsigned long *outlen){   unsigned long t, x, y, z;   unsigned char c;   int           g;   LTC_ARGCHK(in     != NULL);   LTC_ARGCHK(out    != NULL);   LTC_ARGCHK(outlen != NULL);   g = 3;   for (x = y = z = t = 0; x < inlen; x++) {       c = map[in[x]&0xFF];       if (c == 255) continue;       /* the final = symbols are read and used to trim the remaining bytes */       if (c == 254) {           c = 0;           /* prevent g < 0 which would potentially allow an overflow later */          if (--g < 0) {             return CRYPT_INVALID_PACKET;          }       } else if (g != 3) {          /* we only allow = to be at the end */          return CRYPT_INVALID_PACKET;       }       t = (t<<6)|c;       if (++y == 4) {          if (z + g > *outlen) {              return CRYPT_BUFFER_OVERFLOW;           }          out[z++] = (unsigned char)((t>>16)&255);          if (g > 1) out[z++] = (unsigned char)((t>>8)&255);          if (g > 2) out[z++] = (unsigned char)(t&255);          y = t = 0;       }   }   if (y != 0) {       return CRYPT_INVALID_PACKET;   }   *outlen = z;   return CRYPT_OK;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/misc/base64/base64_decode.c,v $ *//* $Revision: 1.4 $ *//* $Date: 2006/03/31 14:15:35 $ */