COMMON: Add a Huffman bitstream decoder

Based on eos' code

3 files changed, 159 insertions, 0 deletions

diff --git a/common/huffman.cpp b/common/huffman.cpp
new file mode 100644
index 0000000000..668e2216c9
--- /dev/null
+++ b/common/huffman.cpp
@@ -0,0 +1,81 @@
+/* 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 eos' Huffman code
+
+#include "common/huffman.h"
+#include "common/util.h"
+#include "common/textconsole.h"
+#include "common/bitstream.h"
+
+namespace Common {
+
+Huffman::Symbol::Symbol(uint32 c, uint32 s) : code(c), symbol(s) {
+}
+
+
+Huffman::Huffman(uint8 maxLength, uint32 codeCount, const uint32 *codes, const uint8 *lengths, const uint32 *symbols) {
+	assert(maxLength > 0);
+	assert(codeCount > 0);
+
+	assert(codes);
+	assert(lengths);
+
+	_codes.resize(maxLength);
+	_symbols.resize(codeCount);
+
+	for (uint32 i = 0; i < codeCount; i++) {
+		// The symbol. If none were specified, just assume it's identical to the code index
+		uint32 symbol = symbols ? symbols[i] : i;
+
+		// Put the code and symbol into the correct list
+		_codes[lengths[i] - 1].push_back(Symbol(codes[i], symbol));
+
+		// And put the pointer to the symbol/code struct into the symbol list.
+		_symbols[i] = &_codes[lengths[i] - 1].back();
+	}
+}
+
+Huffman::~Huffman() {
+}
+
+void Huffman::setSymbols(const uint32 *symbols) {
+	for (uint32 i = 0; i < _symbols.size(); i++)
+		_symbols[i]->symbol = symbols ? *symbols++ : i;
+}
+
+uint32 Huffman::getSymbol(BitStream &bits) {
+	uint32 code = 0;
+
+	for (uint32 i = 0; i < _codes.size(); i++) {
+		bits.addBit(code, i);
+
+		for (CodeList::const_iterator cCode = _codes[i].begin(); cCode != _codes[i].end(); ++cCode)
+			if (code == cCode->code)
+				return cCode->symbol;
+	}
+
+	error("Unknown Huffman code");
+	return 0;
+}
+
+} // End of namespace Common
diff --git a/common/huffman.h b/common/huffman.h
new file mode 100644
index 0000000000..9c88a37541
--- /dev/null
+++ b/common/huffman.h
@@ -0,0 +1,77 @@
+/* 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 eos' Huffman code
+
+#ifndef COMMON_HUFFMAN_H
+#define COMMON_HUFFMAN_H
+
+#include "common/array.h"
+#include "common/list.h"
+#include "common/types.h"
+
+namespace Common {
+
+class BitStream;
+
+/** Decode a Huffman'd bitstream. */
+class Huffman {
+public:
+	/** Construct a Huffman decoder.
+	 *
+	 *  @param maxLength Maximal code length.
+	 *  @param codeCount Number of codes.
+	 *  @param codes The actual codes.
+	 *  @param lengths Lengths of the individual codes.
+	 *  @param symbols The symbols. If 0, assume they are identical to the code indices.
+	 */
+	Huffman(uint8 maxLength, uint32 codeCount, const uint32 *codes, const uint8 *lengths, const uint32 *symbols = 0);
+	~Huffman();
+
+	/** Modify the codes' symbols. */
+	void setSymbols(const uint32 *symbols = 0);
+
+	/** Return the next symbol in the bitstream. */
+	uint32 getSymbol(BitStream &bits);
+
+private:
+	struct Symbol {
+		uint32 code;
+		uint32 symbol;
+
+		Symbol(uint32 c, uint32 s);
+	};
+
+	typedef Common::List<Symbol> CodeList;
+	typedef Common::Array<CodeList> CodeLists;
+	typedef Common::Array<Symbol *> SymbolList;
+
+	/** Lists of codes and their symbols, sorted by code length. */
+	CodeLists _codes;
+
+	/** Sorted list of pointers to the symbols. */
+	SymbolList _symbols;
+};
+
+} // End of namespace Common
+
+#endif // COMMON_HUFFMAN_H
diff --git a/common/module.mk b/common/module.mk
index d2791c4f9d..7716f74d34 100644
--- a/common/module.mk
+++ b/common/module.mk
@@ -13,6 +13,7 @@ MODULE_OBJS := \
 	file.o \
 	fs.o \
 	hashmap.o \
+	huffman.o \
 	iff_container.o \
 	macresman.o \
 	math.o \