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148 lines
3.1 KiB
C
148 lines
3.1 KiB
C
#ifndef __BITCODER_H
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#define __BITCODER_H
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#include "mem.h"
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#if defined(BITCODER)
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#define OUTPUT_BIT(coder,bit) bitcoder_write_bit(coder,bit)
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#define INPUT_BIT(coder) bitcoder_read_bit(coder)
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#define OUTPUT_BIT_DIRECT(coder,bit) bitcoder_write_bit(coder,bit)
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#define INPUT_BIT_DIRECT(coder) bitcoder_read_bit(coder)
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#define ENTROPY_CODER BitCoderState
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#define ENTROPY_ENCODER_init(coder,limit) bitcoder_coder_init(coder,limit)
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#define ENTROPY_ENCODER_DONE(coder) bitcoder_encoder_done(coder)
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#define ENTROPY_ENCODER_FLUSH(coder) bitcoder_flush(coder)
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#define ENTROPY_DECODER_INIT(coder,bitstream,limit) \
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bitcoder_decoder_init(coder,bitstream,limit)
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#define ENTROPY_DECODER_DONE(coder) /* nothing to do ... */
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#define ENTROPY_CODER_BITSTREAM(coder) (coder)->bitstream
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#define ENTROPY_CODER_SYMBOL(coder) 1
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#define ENTROPY_CODER_RUNLENGTH(coder) 0
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#define ENTROPY_CODER_SKIP(coder,skip)
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#endif
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typedef struct
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{
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int32_t bit_count; /* number of valid bits in byte */
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uint8_t byte; /* buffer to save bits */
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uint32_t byte_count; /* number of bytes written */
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uint8_t *bitstream;
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uint32_t limit; /* don't write more bytes to bitstream ... */
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int eos; /* end of stream reached */
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} BitCoderState;
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static inline void
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bitcoder_encoder_init (BitCoderState * s, uint32_t limit)
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{
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s->bit_count = 0;
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s->byte = 0;
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s->byte_count = 0;
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s->bitstream = (uint8_t *) MALLOC (limit);
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s->limit = limit;
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s->eos = 0;
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}
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static inline void
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bitcoder_encoder_done (BitCoderState * s)
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{
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FREE (s->bitstream);
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}
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static inline void
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bitcoder_decoder_init (BitCoderState * s, uint8_t * bitstream, uint32_t limit)
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{
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s->bit_count = -1;
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s->byte = 0;
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s->byte_count = 0;
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s->bitstream = bitstream;
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s->limit = limit;
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s->eos = 0;
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}
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static inline uint32_t
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bitcoder_flush (BitCoderState * s)
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{
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if (s->bit_count > 0 && s->byte_count < s->limit)
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s->bitstream[s->byte_count++] = s->byte << (8 - s->bit_count);
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/*printf ("%s: %i bytes written.\n", __FUNCTION__, s->byte_count); */
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/*printf ("%s: last bit %i\n", __FUNCTION__, s->bit_count); */
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return s->byte_count;
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}
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static inline void
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bitcoder_write_bit (BitCoderState * s, int bit)
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{
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s->byte <<= 1;
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s->byte |= bit & 1;
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s->bit_count++;
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if (s->bit_count == 8) {
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if (s->byte_count < s->limit) {
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s->bitstream[s->byte_count++] = s->byte;
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s->bit_count = 0;
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} else {
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s->eos = 1;
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}
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}
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}
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static inline int
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bitcoder_read_bit (BitCoderState * s)
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{
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int ret;
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if (s->bit_count <= 0) {
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if (!s->bitstream) {
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s->eos = 1;
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return 0;
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}
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if (s->byte_count < s->limit) {
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s->byte = s->bitstream[s->byte_count++];
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} else {
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s->eos = 1;
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s->byte = 0;
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}
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s->bit_count = 8;
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}
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ret = s->byte >> 7;
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s->byte <<= 1;
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s->bit_count--;
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return ret & 1;
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}
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static inline void
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bit_print (TYPE byte)
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{
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int bit = 8 * sizeof (TYPE);
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do {
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bit--;
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printf ((byte & (1 << bit)) ? "1" : "0");
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} while (bit);
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printf ("\n");
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}
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#endif
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