1 files changed, 89 insertions, 0 deletions
diff --git a/src/engine/shared/huffman.h b/src/engine/shared/huffman.h
new file mode 100644
index 00000000..5aa56c8f
--- /dev/null
+++ b/src/engine/shared/huffman.h
@@ -0,0 +1,89 @@
+#ifndef ENGINE_SHARED_HUFFMAN_H
+#define ENGINE_SHARED_HUFFMAN_H
+
+
+
+class CHuffman
+{
+	enum
+	{
+		HUFFMAN_EOF_SYMBOL = 256,
+
+		HUFFMAN_MAX_SYMBOLS=HUFFMAN_EOF_SYMBOL+1,
+		HUFFMAN_MAX_NODES=HUFFMAN_MAX_SYMBOLS*2-1,
+		
+		HUFFMAN_LUTBITS = 10,
+		HUFFMAN_LUTSIZE = (1<<HUFFMAN_LUTBITS),
+		HUFFMAN_LUTMASK = (HUFFMAN_LUTSIZE-1)
+	};
+
+	struct CNode
+	{
+		// symbol
+		unsigned m_Bits;
+		unsigned m_NumBits;
+
+		// don't use pointers for this. shorts are smaller so we can fit more data into the cache
+		unsigned short m_aLeafs[2];
+
+		// what the symbol represents
+		unsigned char m_Symbol;
+	};
+
+	CNode m_aNodes[HUFFMAN_MAX_NODES];
+	CNode *m_apDecodeLut[HUFFMAN_LUTSIZE];
+	CNode *m_pStartNode;
+	int m_NumNodes;
+	
+	void Setbits_r(CNode *pNode, int Bits, int Depth);
+	void ConstructTree(const unsigned *pFrequencies);
+	
+public:
+	/*
+		Function: huffman_init
+			Inits the compressor/decompressor.
+
+		Parameters:
+			huff - Pointer to the state to init
+			frequencies - A pointer to an array of 256 entries of the frequencies of the bytes
+
+		Remarks:
+			- Does no allocation what so ever.
+			- You don't have to call any cleanup functions when you are done with it
+	*/
+	void Init(const unsigned *pFrequencies);
+
+	/*
+		Function: huffman_compress
+			Compresses a buffer and outputs a compressed buffer.
+
+		Parameters:
+			huff - Pointer to the huffman state
+			input - Buffer to compress
+			input_size - Size of the buffer to compress
+			output - Buffer to put the compressed data into
+			output_size - Size of the output buffer
+
+		Returns:
+			Returns the size of the compressed data. Negative value on failure.
+	*/
+	int Compress(const void *pInput, int InputSize, void *pOutput, int OutputSize);
+
+	/*
+		Function: huffman_decompress
+			Decompresses a buffer
+
+		Parameters:
+			huff - Pointer to the huffman state
+			input - Buffer to decompress
+			input_size - Size of the buffer to decompress
+			output - Buffer to put the uncompressed data into
+			output_size - Size of the output buffer
+
+		Returns:
+			Returns the size of the uncompressed data. Negative value on failure.
+	*/
+	int Decompress(const void *pInput, int InputSize, void *pOutput, int OutputSize);
+	
+};
+#endif // __HUFFMAN_HEADER__