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#ifndef __HUFFMAN_HEADER__
#define __HUFFMAN_HEADER__
#ifdef __cplusplus
extern "C" {
#endif
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)
};
typedef struct HUFFMAN_NODE
{
/* symbol */
unsigned bits;
unsigned num_bits;
/* don't use pointers for this. shorts are smaller so we can fit more data into the cache */
unsigned short leafs[2];
/* what the symbol represents */
unsigned char symbol;
} HUFFMAN_NODE;
typedef struct HUFFMAN_STATE
{
HUFFMAN_NODE nodes[HUFFMAN_MAX_NODES];
HUFFMAN_NODE *decode_lut[HUFFMAN_LUTSIZE];
HUFFMAN_NODE *start_node;
int num_nodes;
} HUFFMAN_STATE;
/*
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 huffman_init(HUFFMAN_STATE *huff, const unsigned *frequencies);
/*
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 huffman_compress(HUFFMAN_STATE *huff, const void *input, int input_size, void *output, int output_size);
/*
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 huffman_decompress(HUFFMAN_STATE *huff, const void *input, int input_size, void *output, int output_size);
#ifdef __cplusplus
}
#endif
#endif /* __HUFFMAN_HEADER__ */
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