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-rw-r--r--engines/dm/lzw.cpp189
-rw-r--r--engines/dm/lzw.h64
-rw-r--r--engines/dm/module.mk1
3 files changed, 254 insertions, 0 deletions
diff --git a/engines/dm/lzw.cpp b/engines/dm/lzw.cpp
new file mode 100644
index 0000000000..c5acc9c023
--- /dev/null
+++ b/engines/dm/lzw.cpp
@@ -0,0 +1,189 @@
+/* ScummVM - Graphic Adventure Engine
+*
+* ScummVM is the legal property of its developers, whose names
+* are too numerous to list here. Please refer to the COPYRIGHT
+* file distributed with this source distribution.
+*
+* 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.
+*
+*/
+
+/*
+* Based on the Reverse Engineering work of Christophe Fontanel,
+* maintainer of the Dungeon Master Encyclopaedia (http://dmweb.free.fr/)
+*/
+
+#include "lzw.h"
+#include <common/memstream.h>
+
+namespace DM {
+
+LZWdecompressor::LZWdecompressor() {
+ _repetitionEnabled = false;
+ _codeBitCount = 0;
+ _currentMaximumCode = 0;
+ _absoluteMaximumCode = 4096;
+ for (int i = 0; i < 12; ++i)
+ _inputBuffer[i] = 0;
+ _dictNextAvailableCode = 0;
+ _dictFlushed = false;
+
+ byte leastSignificantBitmasks[9] = {0x00,0x01,0x03,0x07,0x0F,0x1F,0x3F,0x7F,0xFF};
+ for (uint16 i = 0; i < 9; ++i)
+ _leastSignificantBitmasks[i] = leastSignificantBitmasks[i];
+ _inputBufferBitIndex = 0;
+ _inputBufferBitCount = 0;
+ _charToRepeat = 0;
+
+ _tempBuffer = new byte[5004];
+ _prefixCode = new int16[5003];
+ _appendCharacter = new byte[5226];
+}
+
+LZWdecompressor::~LZWdecompressor() {
+ delete[] _appendCharacter;
+ delete[] _prefixCode;
+ delete[] _tempBuffer;
+}
+
+int16 LZWdecompressor::getNextInputCode(Common::MemoryReadStream &inputStream, int32 *inputByteCount) {
+ byte *inputBuffer = _inputBuffer;
+ if (_dictFlushed || (_inputBufferBitIndex >= _inputBufferBitCount) || (_dictNextAvailableCode > _currentMaximumCode)) {
+ if (_dictNextAvailableCode > _currentMaximumCode) {
+ _codeBitCount++;
+ if (_codeBitCount == 12) {
+ _currentMaximumCode = _absoluteMaximumCode;
+ } else {
+ _currentMaximumCode = (1 << _codeBitCount) - 1;
+ }
+ }
+ if (_dictFlushed) {
+ _currentMaximumCode = (1 << (_codeBitCount = 9)) - 1;
+ _dictFlushed = false;
+ }
+ if (*inputByteCount > _codeBitCount) {
+ _inputBufferBitCount = _codeBitCount;
+ } else {
+ _inputBufferBitCount = *inputByteCount;
+ }
+ if (_inputBufferBitCount > 0) {
+ inputStream.read(_inputBuffer, _inputBufferBitCount);
+ *inputByteCount -= _inputBufferBitCount;
+ } else {
+ return -1;
+ }
+ _inputBufferBitIndex = 0;
+ _inputBufferBitCount = (_inputBufferBitCount << 3) - (_codeBitCount - 1);
+ }
+ int16 bitIndex = _inputBufferBitIndex;
+ int16 requiredInputBitCount = _codeBitCount;
+ inputBuffer += bitIndex >> 3; /* Address of byte in input buffer containing current bit */
+ bitIndex &= 0x0007; /* Bit index of the current bit in the byte */
+ int16 nextInputCode = *inputBuffer++ >> bitIndex; /* Get the first bits of the next input code from the input buffer byte */
+ requiredInputBitCount -= 8 - bitIndex; /* Remaining number of bits to get for a complete input code */
+ bitIndex = 8 - bitIndex;
+ if (requiredInputBitCount >= 8) {
+ nextInputCode |= *inputBuffer++ << bitIndex;
+ bitIndex += 8;
+ requiredInputBitCount -= 8;
+ }
+ nextInputCode |= (*inputBuffer & _leastSignificantBitmasks[requiredInputBitCount]) << bitIndex;
+ _inputBufferBitIndex += _codeBitCount;
+ return nextInputCode;
+}
+
+void LZWdecompressor::F0496_LZW_OutputCharacter(byte character, byte **out) {
+ byte *L1558_pc_Output = *out;
+
+ if (false == _repetitionEnabled) {
+ if (character == 0x90) {
+ _repetitionEnabled = true;
+ } else {
+ *L1558_pc_Output++ = _charToRepeat = character;
+ }
+ *out = L1558_pc_Output;
+ return;
+ } else {
+ if (character) { /* If character following 0x90 is not 0x00 then it is the repeat count */
+ while (--character) {
+ *L1558_pc_Output++ = _charToRepeat;
+ }
+ } else { /* else output a 0x90 character */
+ *L1558_pc_Output++ = 0x90;
+ }
+ _repetitionEnabled = false;
+ *out = L1558_pc_Output;
+ return;
+ }
+}
+
+int32 LZWdecompressor::decompress(Common::MemoryReadStream &inStream, int32 inputByteCount, byte *out) {
+ byte *reversedDecodedStringStart;
+ byte *reversedDecodedStringEnd = reversedDecodedStringStart = _tempBuffer;
+ byte *originalOut = out;
+ _repetitionEnabled = false;
+ _codeBitCount = 9;
+ _dictFlushed = false;
+ _currentMaximumCode = (1 << (_codeBitCount = 9)) - 1;
+ for (int16 code = 255; code >= 0; code--) {
+ _prefixCode[code] = 0;
+ _appendCharacter[code] = code;
+ }
+ _dictNextAvailableCode = 257;
+ int16 oldCode;
+ int16 character = oldCode = getNextInputCode(inStream, &inputByteCount);
+ if (oldCode == -1) {
+ return -1L;
+ }
+ F0496_LZW_OutputCharacter(character, &out);
+ int16 code;
+ while ((code = getNextInputCode(inStream, &inputByteCount)) > -1) {
+ if (code == 256) { /* This code is used to flush the dictionary */
+ for (int i = 0; i < 256; ++i)
+ _prefixCode[i] = 0;
+ _dictFlushed = true;
+ _dictNextAvailableCode = 256;
+ if ((code = getNextInputCode(inStream, &inputByteCount)) == -1) {
+ break;
+ }
+ }
+ /* This code checks for the special STRING+CHARACTER+STRING+CHARACTER+STRING case which generates an undefined code.
+ It handles it by decoding the last code, adding a single character to the end of the decoded string */
+ int16 newCode = code;
+ if (code >= _dictNextAvailableCode) { /* If code is not defined yet */
+ *reversedDecodedStringEnd++ = character;
+ code = oldCode;
+ }
+ /* Use the string table to decode the string corresponding to the code and store the string in the temporary buffer */
+ while (code >= 256) {
+ *reversedDecodedStringEnd++ = _appendCharacter[code];
+ code = _prefixCode[code];
+ }
+ *reversedDecodedStringEnd++ = (character = _appendCharacter[code]);
+ /* Output the decoded string in reverse order */
+ do {
+ F0496_LZW_OutputCharacter(*(--reversedDecodedStringEnd), &out);
+ } while (reversedDecodedStringEnd > reversedDecodedStringStart);
+ /* If possible, add a new code to the string table */
+ if ((code = _dictNextAvailableCode) < _absoluteMaximumCode) {
+ _prefixCode[code] = oldCode;
+ _appendCharacter[code] = character;
+ _dictNextAvailableCode = code + 1;
+ }
+ oldCode = newCode;
+ }
+ return out - originalOut; /* Byte count of decompressed data */
+}
+}
diff --git a/engines/dm/lzw.h b/engines/dm/lzw.h
new file mode 100644
index 0000000000..80c18c5eb5
--- /dev/null
+++ b/engines/dm/lzw.h
@@ -0,0 +1,64 @@
+/* ScummVM - Graphic Adventure Engine
+*
+* ScummVM is the legal property of its developers, whose names
+* are too numerous to list here. Please refer to the COPYRIGHT
+* file distributed with this source distribution.
+*
+* 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.
+*
+*/
+
+/*
+* Based on the Reverse Engineering work of Christophe Fontanel,
+* maintainer of the Dungeon Master Encyclopaedia (http://dmweb.free.fr/)
+*/
+
+#include <common/file.h>
+
+#include "dm.h"
+
+namespace Common {
+ class MemoryReadStream;
+}
+
+namespace DM {
+class LZWdecompressor {
+ bool _repetitionEnabled;
+ int16 _codeBitCount;
+ int16 _currentMaximumCode;
+ int16 _absoluteMaximumCode;
+ byte _inputBuffer[12];
+ int16 _dictNextAvailableCode;
+ bool _dictFlushed;
+
+ byte _leastSignificantBitmasks[9];
+ int16 _inputBufferBitIndex;
+ int16 _inputBufferBitCount;
+ int16 _charToRepeat;
+
+ byte* _tempBuffer;
+ int16 *_prefixCode;
+ byte *_appendCharacter;
+
+ int16 getNextInputCode(Common::MemoryReadStream &stream, int32 *inputByteCount);
+ void F0496_LZW_OutputCharacter(byte character, byte **out);
+ void operator=(const LZWdecompressor&); // deleted
+public:
+ LZWdecompressor();
+ ~LZWdecompressor();
+ int32 decompress(Common::MemoryReadStream &inputStream, int32 inputByteCount, byte *out);
+};
+
+}
diff --git a/engines/dm/module.mk b/engines/dm/module.mk
index 559ebf1707..d495284da5 100644
--- a/engines/dm/module.mk
+++ b/engines/dm/module.mk
@@ -41,6 +41,7 @@ MODULE_OBJS := \
group.o \
inventory.o \
loadsave.o \
+ lzw.o \
menus.o \
movesens.o \
objectman.o \
generated by cgit v1.2.3 (git 2.25.1) at 2025-04-17 10:36:35 +0000