/****************************************************************************
 * ResortMUD 4.0 Beta by Ntanel, Garinan, Badastaz, Josh, Digifuzz, Senir,  *
 * Kratas, Scion, Shogar and Tagith.  Special thanks to Thoric, Nivek,      *
 * Altrag, Arlorn, Justice, Samson, Dace, HyperEye and Yakkov.              *
 ****************************************************************************
 * Copyright (C) 1996 - 2001 Haslage Net Electronics: MudWorld              *
 * of Lorain, Ohio - ALL RIGHTS RESERVED                                    *
 * The text and pictures of this publication, or any part thereof, may not  *
 * be reproduced or transmitted in any form or by any means, electronic or  *
 * mechanical, includes photocopying, recording, storage in a information   *
 * retrieval system, or otherwise, without the prior written or e-mail      *
 * consent from the publisher.                                              *
 ****************************************************************************
 * GREETING must mention ResortMUD programmers and the help file named      *
 * CREDITS must remain completely intact as listed in the SMAUG license.    *
 ****************************************************************************/

/*
 * Base64 Decoder, for the webserver basic authentication
 * stuff, not mine found it kicking about at 
 * http://local.15seconds.com/faq/pg00934.htm
 * All credit to John Ludeman for this code :)
 * 
 * Only change made is to cast the data access to pr2six
 * to type (int) to prevent gcc from moaning its head off 
 * while using -Wall
 */


#include <stdio.h>

/* Thanks to John Ludeman for this code...
 * Define translation matrix for Base64 decode.
 * it's fast and const should make it shared text page.
 */
const int pr2six[256] = {
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
   52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64, 64, 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, 64, 64, 64, 64, 64, 64, 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,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
};

/*
 * Decode a base64 encoded string
 */
void Base64Decode( char *bufcoded, unsigned char *bufplain, int outbufsize )
{
   int nbytesdecoded;
   int nprbytes;
   char *bufin = bufcoded;
   unsigned char *bufout = bufplain;

   /*
    * Strip leading whitespace 
    */
   while( *bufcoded == ' ' || *bufcoded == '\t' )
      ++bufcoded;

   /*
    * Figure out how many characters are in the input buffer.
    * If this would decode into more bytes than would fit into
    * the output buffer, adjust the number of input bytes downwards.
    */
   bufin = bufcoded;
   while( pr2six[( int )*( bufin++ )] <= 63 )
      ;
   nprbytes = bufin - bufcoded - 1;
   nbytesdecoded = ( ( nprbytes + 3 ) / 4 ) * 3;
   if( nbytesdecoded > outbufsize )
      nprbytes = ( outbufsize * 4 ) / 3;

   bufin = bufcoded;
   while( nprbytes > 0 )
   {
      *( bufout++ ) = ( unsigned char )( pr2six[( int )*bufin] << 2 | pr2six[( int )bufin[1]] >> 4 );
      *( bufout++ ) = ( unsigned char )( pr2six[( int )bufin[1]] << 4 | pr2six[( int )bufin[2]] >> 2 );
      *( bufout++ ) = ( unsigned char )( pr2six[( int )bufin[2]] << 6 | pr2six[( int )bufin[3]] );
      bufin += 4;
      nprbytes -= 4;
   }

   if( nprbytes & 03 )
   {
      if( pr2six[( int )bufin[-2]] > 63 )
         nbytesdecoded -= 2;
      else
         nbytesdecoded -= 1;
   }
   bufplain[nbytesdecoded] = '\0';
}