Initial commit

engines/bagel/hodjnpodj/hnplibs/lzss.cpp

@@ -0,0 +1,97 @@
+/* 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 "common/file.h"
+#include "common/memstream.h"
+#include "bagel/hodjnpodj/hnplibs/lzss.h"
+
+namespace Bagel {
+namespace HodjNPodj {
+
+Common::SeekableReadStream *makeLzssStream(const Common::Path &filename) {
+	Common::File file;
+	if (!file.open(filename))
+		return nullptr;
+
+	// First part of the signature
+	if (file.readUint32BE() != MKTAG('S', 'Z', 'D', 'D'))
+		return nullptr;
+
+	// Second part of the signature
+	if (file.readUint32BE() != 0x88F02733)
+		return nullptr;
+
+	// Compression mode must be 'A'
+	if (file.readByte() != 'A')
+		return nullptr;
+
+	file.readByte(); // file name character change
+	uint32 unpackedLength = file.readUint32LE();
+
+	byte *window = new byte[0x1000]();
+	int pos = 0x1000 - 16;
+
+	byte *unpackedData = (byte *)malloc(unpackedLength);
+	assert(unpackedData);
+	byte *dataPos = unpackedData;
+
+	uint32 remaining = unpackedLength;
+
+	// Apply simple LZSS decompression
+	for (;;) {
+		byte controlByte = file.readByte();
+
+		if (remaining == 0 || file.eos())
+			break;
+
+		for (byte i = 0; i < 8; i++) {
+			if (controlByte & (1 << i)) {
+				*dataPos++ = window[pos++] = file.readByte();
+				pos &= 0xFFF;
+				if (--remaining == 0)
+					break;
+			} else {
+				int matchPos = file.readByte();
+				int matchLen = file.readByte();
+				matchPos |= (matchLen & 0xF0) << 4;
+				matchLen = (matchLen & 0xF) + 3;
+				if ((uint32)matchLen > remaining)
+					matchLen = remaining;
+				remaining -= matchLen;
+
+				while (matchLen--) {
+					*dataPos++ = window[pos++] = window[matchPos++];
+					pos &= 0xFFF;
+					matchPos &= 0xFFF;
+				}
+
+				if (remaining == 0)
+					break;
+			}
+		}
+	}
+
+	delete[] window;
+	return new Common::MemoryReadStream(unpackedData, unpackedLength);
+}
+
+} // namespace HodjNPodj
+} // namespace Bagel