scummvm/engines/lure/decode.cpp
2006-02-11 22:45:04 +00:00

361 lines
8.0 KiB
C++

/* ScummVM - Scumm Interpreter
* Copyright (C) 2005-2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "lure/decode.h"
#include "lure/memory.h"
#include "lure/luredefs.h"
namespace Lure {
/*--------------------------------------------------------------------------*/
/* PictureDecoder class */
/* */
/* Provides the functionality for decoding screens */
/*--------------------------------------------------------------------------*/
void PictureDecoder::writeByte(MemoryBlock *dest, byte v) {
if (outputOffset == dest->size())
error("Decoded data exceeded allocated output buffer size");
dest->data()[outputOffset++] = v;
}
void PictureDecoder::writeBytes(MemoryBlock *dest, byte v, uint16 numBytes) {
if (outputOffset + numBytes > dest->size())
error("Decoded data exceeded allocated output buffer size");
dest->memorySet(v, outputOffset, numBytes);
outputOffset += numBytes;
}
byte PictureDecoder::DSSI(bool incr) {
byte result = dataIn[dataPos];
if (incr) ++dataPos;
return result;
}
byte PictureDecoder::ESBX(bool incr) {
byte result = dataIn[dataPos2];
if (incr) ++dataPos2;
return result;
}
void PictureDecoder::decrCtr() {
--CL;
if (CL == 0) {
CH = ESBX();
CL = 8;
}
}
bool PictureDecoder::shlCarry() {
bool result = (CH & 0x80) != 0;
CH <<= 1;
return result;
}
void PictureDecoder::swap(uint16 &v1, uint16 &v2) {
uint16 vTemp;
vTemp = v1;
v1 = v2;
v2 = vTemp;
}
// decode_data
// Takes care of decoding compressed Lure of the Temptress data
MemoryBlock *PictureDecoder::decode(MemoryBlock *src, uint32 maxOutputSize) {
MemoryBlock *dest = Memory::allocate(maxOutputSize);
// Set up initial states
dataIn = src->data();
outputOffset = 0;
dataPos = READ_LE_UINT32(dataIn + 0x400);
dataPos2 = 0x404;
CH = ESBX();
CL = 9;
Loc754:
AL = DSSI();
writeByte(dest, AL);
BP = ((uint16) AL) << 2;
Loc755:
decrCtr();
if (shlCarry()) goto Loc761;
decrCtr();
if (shlCarry()) goto Loc759;
AL = dataIn[BP];
Loc758:
writeByte(dest, AL);
BP = ((uint16) AL) << 2;
goto Loc755;
Loc759:
AL = (byte) (BP >> 2);
AH = DSSI();
if (AH == 0) goto Loc768;
writeBytes(dest, AL, AH);
goto Loc755;
Loc761:
decrCtr();
if (shlCarry()) goto Loc765;
decrCtr();
if (shlCarry()) goto Loc764;
AL = dataIn[BP+1];
goto Loc758;
Loc764:
AL = dataIn[BP+2];
goto Loc758;
Loc765:
decrCtr();
if (shlCarry()) goto Loc767;
AL = dataIn[BP+3];
goto Loc758;
Loc767:
goto Loc754;
Loc768:
AL = DSSI();
if (AL != 0) goto Loc755;
// Resize the output to be the number of outputed bytes and return it
if (outputOffset < dest->size()) dest->reallocate(outputOffset);
return dest;
}
/*--------------------------------------------------------------------------*/
/* AnimationDecoder class */
/* */
/* Provides the functionality for decoding animations */
/*--------------------------------------------------------------------------*/
// The code below is responsible for decompressing the pixel data
// for an animation. I'm not currently sure of the of the exact details
// of the compression format - for now I've simply copied the code
// from the executable
void AnimationDecoder::rcl(uint16 &value, bool &carry) {
bool result = (value & 0x8000) != 0;
value = (value << 1) + (carry ? 1 : 0);
carry = result;
}
#define GET_BYTE currData = (currData & 0xff00) | *pSrc++
#define BX_VAL(x) *((byte *) (dest->data() + tableOffset + x))
#define SET_HI_BYTE(x,v) x = (x & 0xff) | ((v) << 8);
#define SET_LO_BYTE(x,v) x = (x & 0xff00) | (v);
void AnimationDecoder::decode_data_2(byte *&pSrc, uint16 &currData, uint16 &bitCtr,
uint16 &dx, bool &carry) {
SET_HI_BYTE(dx, currData >> 8);
for (int v = 0; v < 8; ++v) {
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
}
}
uint32 AnimationDecoder::decode_data(MemoryBlock *src, MemoryBlock *dest, uint32 srcPos) {
byte *pSrc = src->data() + srcPos;
byte *pDest = dest->data();
byte v;
bool carry = false;
uint16 currData, bitCtr, dx;
byte tableOffset;
uint16 tempReg1, tempReg2;
// Handle splitting up 16 bytes into individual nibbles
for (int numBytes = 0; numBytes < 16; ++numBytes, ++pDest) {
// Split up next byte to pDest and pDest+0x10
currData = *pSrc++;
*(pDest + 0x10) = currData & 0xf;
*pDest = (currData >> 4) & 0xf;
// Split up next byte to pDest+0x20 and pDest+0x30
currData = *pSrc++;
*(pDest + 0x30) = currData & 0xf;
*(pDest + 0x20) = (currData >> 4) & 0xf;
}
pDest = (byte *) (dest->data() + 0x40);
currData = READ_BE_UINT16(pSrc);
pSrc += sizeof(uint16);
bitCtr = 4;
*pDest = (currData >> 8) & 0xf0;
tableOffset = currData >> 12;
currData <<= 4;
dx = 1;
for (;;) {
carry = false;
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
if (carry) goto loc_1441;
tableOffset = BX_VAL(0);
loc_1439:
dx ^= 1;
if ((dx & 1) != 0) {
SET_HI_BYTE(dx, tableOffset << 4);
*pDest = dx >> 8;
} else {
*pDest++ |= tableOffset;
}
continue;
loc_1441:
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
if (!carry) {
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
if (!carry) {
tableOffset = BX_VAL(0x10);
} else {
tableOffset = BX_VAL(0x20);
}
goto loc_1439;
}
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
if (!carry) {
tableOffset = BX_VAL(0x30);
goto loc_1439;
}
SET_HI_BYTE(dx, currData >> 12);
carry = false;
for (int ctr = 0; ctr < 4; ++ctr) {
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
}
byte dxHigh = dx >> 8;
if (dxHigh == BX_VAL(0)) {
tempReg1 = bitCtr;
tempReg2 = dx;
decode_data_2(pSrc, currData, bitCtr, dx, carry);
SET_LO_BYTE(dx, dx >> 8);
decode_data_2(pSrc, currData, bitCtr, dx, carry);
SET_HI_BYTE(bitCtr, dx & 0xff);
SET_LO_BYTE(bitCtr, dx >> 8);
dx = tempReg2;
if (bitCtr == 0)
// Exit out of infinite loop
break;
} else if (dxHigh == BX_VAL(0x10)) {
tempReg1 = bitCtr;
decode_data_2(pSrc, currData, bitCtr, dx, carry);
bitCtr = dx >> 8;
} else if (dxHigh == BX_VAL(0x20)) {
SET_HI_BYTE(dx, currData >> 10);
for (v = 0; v < 6; ++v) {
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
}
tempReg1 = bitCtr;
bitCtr = dx >> 8;
} else if (dxHigh == BX_VAL(0x30)) {
SET_HI_BYTE(dx, currData >> 11);
for (v = 0; v < 5; ++v) {
rcl(currData, carry);
if (--bitCtr == 0) {
GET_BYTE;
bitCtr = 8;
}
}
tempReg1 = bitCtr;
bitCtr = dx >> 8;
} else {
tableOffset = dx >> 8;
goto loc_1439;
}
if ((dx & 1) == 1) {
*pDest++ |= tableOffset;
--bitCtr;
dx &= 0xfffe;
}
SET_HI_BYTE(dx, tableOffset << 4);
tableOffset |= dx >> 8;
v = bitCtr >> 1;
while (v-- > 0) *pDest++ = tableOffset;
bitCtr &= 1;
if (bitCtr != 0) {
*pDest = tableOffset & 0xf0;
dx |= 1; //dx.l
}
bitCtr = tempReg1;
tableOffset &= 0x0f;
}
// Return number of bytes written
return pDest - dest->data();
}
} // end of namespace Lure