gstreamer/ext/tarkin/bitcoder.h

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