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/* AWE - Another World Engine
* Copyright (C) 2004 Gregory Montoir
* Copyright (C) 2004 The ScummVM project
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "common/stdafx.h"
#include "awe/awe.h"
#include "awe/bank.h"
#include "awe/file.h"
#include "awe/resource.h"
namespace Awe {
Bank::Bank(const char *dataDir)
: _dataDir(dataDir) {
}
bool Bank::read(const MemEntry *me, uint8 *buf) {
bool ret = false;
char bankName[10];
sprintf(bankName, "bank%02x", me->bankNum);
File f;
if (f.open(bankName, _dataDir)) {
f.seek(me->bankPos);
if (me->packedSize == me->unpackedSize) {
f.read(buf, me->packedSize);
ret = true;
} else {
f.read(buf, me->packedSize);
_startBuf = buf;
_iBuf = buf + me->packedSize - 4;
ret = unpack();
}
} else {
::error("Bank::read() unable to open '%s'", bankName);
}
return ret;
}
void Bank::decUnk1(uint8 numChunks, uint8 addCount) {
uint16 count = getCode(numChunks) + addCount + 1;
debug(DBG_BANK, "Bank::decUnk1(%d, %d) count=%d", numChunks, addCount, count);
_unpCtx.datasize -= count;
while (count--) {
assert(_oBuf >= _iBuf && _oBuf >= _startBuf);
*_oBuf = (uint8)getCode(8);
--_oBuf;
}
}
void Bank::decUnk2(uint8 numChunks) {
uint16 i = getCode(numChunks);
uint16 count = _unpCtx.size + 1;
debug(DBG_BANK, "Bank::decUnk2(%d) i=%d count=%d", numChunks, i, count);
_unpCtx.datasize -= count;
while (count--) {
assert(_oBuf >= _iBuf && _oBuf >= _startBuf);
*_oBuf = *(_oBuf + i);
--_oBuf;
}
}
bool Bank::unpack() {
_unpCtx.size = 0;
_unpCtx.datasize = READ_BE_UINT32(_iBuf); _iBuf -= 4;
_oBuf = _startBuf + _unpCtx.datasize - 1;
_unpCtx.crc = READ_BE_UINT32(_iBuf); _iBuf -= 4;
_unpCtx.chk = READ_BE_UINT32(_iBuf); _iBuf -= 4;
_unpCtx.crc ^= _unpCtx.chk;
do {
if (!nextChunk()) {
_unpCtx.size = 1;
if (!nextChunk()) {
decUnk1(3, 0);
} else {
decUnk2(8);
}
} else {
uint16 c = getCode(2);
if (c == 3) {
decUnk1(8, 8);
} else {
if (c < 2) {
_unpCtx.size = c + 2;
decUnk2(c + 9);
} else {
_unpCtx.size = getCode(8);
decUnk2(12);
}
}
}
} while (_unpCtx.datasize > 0);
return (_unpCtx.crc == 0);
}
uint16 Bank::getCode(uint8 numChunks) {
uint16 c = 0;
while (numChunks--) {
c <<= 1;
if (nextChunk()) {
c |= 1;
}
}
return c;
}
bool Bank::nextChunk() {
bool CF = rcr(false);
if (_unpCtx.chk == 0) {
assert(_iBuf >= _startBuf);
_unpCtx.chk = READ_BE_UINT32(_iBuf); _iBuf -= 4;
_unpCtx.crc ^= _unpCtx.chk;
CF = rcr(true);
}
return CF;
}
bool Bank::rcr(bool CF) {
bool rCF = (_unpCtx.chk & 1);
_unpCtx.chk >>= 1;
if (CF) _unpCtx.chk |= 0x80000000;
return rCF;
}
}
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