Initial commit

engines/twine/resources/lzss.cpp

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+/* 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 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/>.
+ *
+ */
+
+#include "twine/resources/lzss.h"
+#include "common/textconsole.h"
+
+namespace TwinE {
+
+LzssReadStream::LzssReadStream(Common::ReadStream *indata, uint32 mode, uint32 realsize) {
+	_outLzssBufData = new uint8[realsize]();
+	decodeLZSS(indata, mode, realsize);
+	_size = realsize;
+	_pos = 0;
+	delete indata;
+}
+
+LzssReadStream::~LzssReadStream() {
+	delete[] _outLzssBufData;
+}
+
+void LzssReadStream::decodeLZSS(Common::ReadStream *in, uint32 mode, uint32 dataSize) {
+	if (in->eos() || in->err() || dataSize == 0) {
+		_err = dataSize > 0;
+		return;
+	}
+
+	uint8 *dst = _outLzssBufData;
+	int32 remainingBytes = (int32)dataSize;
+
+	do {
+		uint8 b = in->readByte();
+		for (int32 d = 0; d < 8; d++) {
+			if (in->eos() || in->err()) {
+				_err = dataSize > 0;
+				return;
+			}
+			int32 length;
+			if (!(b & (1 << d))) {
+				const uint16 offset = in->readUint16LE();
+				length = (offset & 0x0F) + (mode + 1);
+				const uint8 *ptr = dst - (offset >> 4) - 1;
+				if (remainingBytes < length) {
+					_err = true;
+					return;
+				}
+				remainingBytes -= length;
+				for (int32 i = 0; i < length; i++) {
+					*dst++ = *ptr++;
+				}
+			} else {
+				length = 1;
+				if (remainingBytes < length) {
+					_err = true;
+					return;
+				}
+				remainingBytes -= length;
+				*dst++ = in->readByte();
+			}
+			dataSize -= length;
+			if (dataSize <= 0) {
+				return;
+			}
+		}
+	} while (dataSize);
+}
+
+bool LzssReadStream::eos() const {
+	return _pos >= _size;
+}
+
+uint32 LzssReadStream::read(void *buf, uint32 dataSize) {
+	if (dataSize > _size - _pos) {
+		_err = true;
+		return 0;
+	}
+
+	memcpy(buf, &_outLzssBufData[_pos], dataSize);
+	_pos += dataSize;
+
+	return dataSize;
+}
+
+bool LzssReadStream::seek(int64 offset, int whence) {
+	if (whence == SEEK_SET) {
+		_pos = offset;
+	} else if (whence == SEEK_CUR) {
+		_pos += offset;
+	}
+	return true;
+}
+
+} // namespace TwinE