b64straw.cpp

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/*
**  Command & Conquer Generals Zero Hour(tm)
**  Copyright 2025 Electronic Arts Inc.
**
**  This program is free software: you can redistribute it and/or modify
**  it under the terms of the GNU General Public License as published by
**  the Free Software Foundation, either version 3 of the License, or
**  (at your option) any later version.
**
**  This program is distributed in the hope that it will be useful,
**  but WITHOUT ANY WARRANTY; without even the implied warranty of
**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
**  GNU General Public License for more details.
**
**  You should have received a copy of the GNU General Public License
**  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
 
/*********************************************************************************************** 
 ***              C O N F I D E N T I A L  ---  W E S T W O O D  S T U D I O S               *** 
 *********************************************************************************************** 
 *                                                                                             * 
 *                 Project Name : Command & Conquer                                            * 
 *                                                                                             * 
 *                     $Archive:: /Commando/Library/B64STRAW.CPP                              $* 
 *                                                                                             * 
 *                      $Author:: Greg_h                                                      $*
 *                                                                                             * 
 *                     $Modtime:: 7/22/97 11:37a                                              $*
 *                                                                                             * 
 *                    $Revision:: 1                                                           $*
 *                                                                                             *
 *---------------------------------------------------------------------------------------------* 
 * Functions:                                                                                  * 
 *   Base64Straw::Get -- Fetch data and convert it to/from base 64 encoding.                   *
 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
#include    "always.h"
#include    "b64straw.h"
#include    "base64.h"
#include    <string.h>
 
 
/***********************************************************************************************
 * Base64Straw::Get -- Fetch data and convert it to/from base 64 encoding.                     *
 *                                                                                             *
 *    This routine will fetch the number of bytes requested and perform any conversion as      *
 *    necessary upon the data. The nature of Base 64 encoding means that the data will         *
 *    increase in size by 30% when encoding and decrease in like manner when decoding.         *
 *                                                                                             *
 * INPUT:   source   -- The buffer to hold the processed data.                                 *
 *                                                                                             *
 *          length   -- The number of bytes requested.                                         *
 *                                                                                             *
 * OUTPUT:  Returns with the number of bytes stored into the buffer. If the number is less     *
 *          than requested, then this indicates that the data stream has been exhausted.       *
 *                                                                                             *
 * WARNINGS:   none                                                                            *
 *                                                                                             *
 * HISTORY:                                                                                    *
 *   07/03/1996 JLB : Created.                                                                 *
 *=============================================================================================*/
int Base64Straw::Get(void * source, int slen)
{
    int total = 0;
 
    char * from;
    int fromsize;
    char * to;
    int tosize;
 
    if (Control == ENCODE) {
        from = PBuffer;
        fromsize = sizeof(PBuffer);
        to = CBuffer;
        tosize = sizeof(CBuffer);
    } else {
        from = CBuffer;
        fromsize = sizeof(CBuffer);
        to = PBuffer;
        tosize = sizeof(PBuffer);
    }
 
    /*
    **  Process the byte request in code blocks until there are either
    **  no more source bytes available or the request has been fulfilled.
    */
    while (slen > 0) {
 
        /*
        **  Transfer any processed bytes available to the request buffer.
        */
        if (Counter > 0) {
            int len = (slen < Counter) ? slen : Counter;
            memmove(source, &to[tosize-Counter], len);
            Counter -= len;
            slen -= len;
            source = ((char *)source) + len;
            total += len;
        }
        if (slen == 0) break;
 
        /*
        **  More bytes are needed, so fetch and process another base 64 block.
        */
        int incount = Straw::Get(from, fromsize);
        if (Control == ENCODE) {
            Counter = Base64_Encode(from, incount, to, tosize);
        } else {
            Counter = Base64_Decode(from, incount, to, tosize);
        }
        if (Counter == 0) break;
    }
 
    return(total);
}