scummvm/engines/cruise/delphine-unpack.cpp

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2006 The ScummVM project
 *
 * cinE Engine is (C) 2004-2005 by CinE Team
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *
 */

#include "cruise/cruise_main.h"

namespace Cruise {

uint32 crc;        // variable at 5C5A
uint32 bitbucket;  // dx:bx

uint16 swap16(uint16 r)
{
  return (r >> 8) | (r << 8);
}

#define loadd(p, d) {\
  d = *(--p);\
  d |= (*(--p)) << 8;\
  d |= (*(--p)) << 16;\
  d |= (*(--p)) << 24;\
}

#define store(p, b) *(--p) = b
#define getbit(p, b) {\
  b = (uint8)(bitbucket & 1);\
  bitbucket >>= 1;\
  if (!bitbucket) {\
    loadd(p, bitbucket);\
    crc ^= bitbucket;\
    b = (uint8)(bitbucket & 1);\
    bitbucket >>= 1;\
    bitbucket |= 0x80000000;\
  }\
}

#define loadbits(p, b) {\
  b = 0;\
  do {\
    getbit(p, bit);\
    b <<= 1;\
    b |= bit;\
    nbits--;\
  } while (nbits);\
}

int32 decomp(uint8 * in, uint8 * out, int32 size) {
    uint8 bit = 0;      // Carry flag
    uint8 nbits = 0;    // cl
    uint8 byte = 0;     // ch
    uint16 counter = 0; // bp
    uint16 var = 0;     // variable at 5C58
    uint16 ptr = 0;
    uint16 flags = 0;
    enum {
      DO_COPY,
      DO_UNPACK
    } action;
   
    loadd(in, crc);
    loadd(in, bitbucket);
    crc ^= bitbucket;

    do { // 5A4C
	getbit(in, bit);
	if (!bit) { // 5A94
	    getbit(in, bit);
	    if (!bit) { // 5AC8
		nbits = 3;
		byte = 0;
		action = DO_COPY;
	    } else { // 5ACA
		var = 1;
    		nbits = 8;
		action = DO_UNPACK;
	    }
	} else { // 5B4F
	    nbits = 2;
	    loadbits(in, flags);
	    if (flags < 2) {
		nbits = flags + 9; // 5BC3
		var = flags + 2;
		action = DO_UNPACK;
	    } else if (flags == 3) {
		nbits = 8; // 5B4A
		byte = 8;
		action = DO_COPY;
	    } else {
		nbits = 8;
		loadbits(in, var);
		nbits = 12;
		action = DO_UNPACK;
	    }
	}

	switch (action) {
	case DO_COPY:
	    // 5AD1
	    loadbits(in, counter); // 5AFD
	    counter += byte;
    	    counter++;
	    size -= counter;
	    do {
		nbits = 8;
		loadbits(in, byte); // 5B3F
		store(out, byte);
		counter--;
	    } while (counter); // 5B45
	    break;
	case DO_UNPACK:
	    // 5BD3
	    loadbits(in, ptr); // 5BFF
	    counter = var + 1;
	    size -= counter;
	    do {
		byte = *(out + ptr - 1);
		store(out, byte);
	        counter--;
	    } while(counter);
	}
    } while (size > 0);
    // 5C32
    // ???
       
    if (crc) {
	return -1;
    } else {
	return 0;
    }
}
/*
int main(void) {
    FILE * in, * out;
    uint8 * bufin, * bufout;
    uint32 isize, osize;

    in = fopen("FIN.FR", "rb");
    out = fopen("FIN.FR.out", "wb");

    fseek(in, -4, SEEK_END);
    bufin = (uint8 *) mallocAndZero((isize = ftell(in)));
    fread(&osize, 4, 1, in);
    osize = (osize >> 24) | ((osize >> 8) & 0xff00) | ((osize << 8) & 0xff0000) | (osize << 24);
    bufout = (uint8 *) mallocAndZero(osize);
    fseek(in, 0, SEEK_SET);
    fread(bufin, 1, isize, in);

    decomp(bufin + isize, bufout + osize, osize);

    fwrite(bufout, 1, osize, out);
    fclose(out);
    fclose(in);
}*/


} // End of namespace Cruise