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#include "mpeg3private.h"
#include "mpeg3protos.h"
#include <stdlib.h>
mpeg3_bits_t* mpeg3bits_new_stream(mpeg3_t *file, mpeg3_demuxer_t *demuxer)
{
mpeg3_bits_t *stream = malloc(sizeof(mpeg3_bits_t));
stream->bfr = 0;
stream->bfr_size = 0;
stream->bit_number = 0;
stream->file = file;
stream->demuxer = demuxer;
stream->input_ptr = 0;
return stream;
}
int mpeg3bits_delete_stream(mpeg3_bits_t* stream)
{
free(stream);
return 0;
}
/* Fill a buffer. Only works if bit_number is on an 8 bit boundary */
int mpeg3bits_read_buffer(mpeg3_bits_t* stream, unsigned char *buffer, int bytes)
{
int result, i = 0;
while(stream->bit_number > 0)
{
stream->bit_number -= 8;
mpeg3demux_read_prev_char(stream->demuxer);
}
stream->bit_number = 0;
stream->bfr_size = 0;
stream->bfr = 0;
result = mpeg3demux_read_data(stream->demuxer, buffer, bytes);
return result;
}
/* For mp3 decompression use a pointer in a buffer for getbits. */
int mpeg3bits_use_ptr(mpeg3_bits_t* stream, unsigned char *buffer)
{
stream->bfr_size = stream->bit_number = 0;
stream->bfr = 0;
stream->input_ptr = buffer;
return 0;
}
/* Go back to using the demuxer for getbits in mp3. */
int mpeg3bits_use_demuxer(mpeg3_bits_t* stream)
{
if(stream->input_ptr)
{
stream->bfr_size = stream->bit_number = 0;
stream->input_ptr = 0;
stream->bfr = 0;
}
return 0;
}
/* Reconfigure for reverse operation */
/* Default is forward operation */
void mpeg3bits_start_reverse(mpeg3_bits_t* stream)
{
int i;
for(i = 0; i < stream->bfr_size; i += 8)
{
if(stream->input_ptr)
stream->input_ptr--;
else
mpeg3demux_read_prev_char(stream->demuxer);
}
}
/* Reconfigure for forward operation */
void mpeg3bits_start_forward(mpeg3_bits_t* stream)
{
int i;
// If already at the bof, the buffer is already invalid.
if(stream->demuxer && mpeg3bits_bof(stream))
{
stream->bfr_size = 0;
stream->bit_number = 0;
stream->bfr = 0;
stream->input_ptr = 0;
mpeg3demux_read_char(stream->demuxer);
}
else
for(i = 0; i < stream->bfr_size; i += 8)
{
if(stream->input_ptr)
stream->input_ptr++;
else
mpeg3demux_read_char(stream->demuxer);
}
}
/* Erase the buffer with the next 4 bytes in the file. */
int mpeg3bits_refill(mpeg3_bits_t* stream)
{
stream->bit_number = 32;
stream->bfr_size = 32;
if(stream->input_ptr)
{
stream->bfr = (unsigned int)(*stream->input_ptr++) << 24;
stream->bfr |= (unsigned int)(*stream->input_ptr++) << 16;
stream->bfr |= (unsigned int)(*stream->input_ptr++) << 8;
stream->bfr |= *stream->input_ptr++;
}
else
{
stream->bfr = mpeg3demux_read_char(stream->demuxer) << 24;
stream->bfr |= mpeg3demux_read_char(stream->demuxer) << 16;
stream->bfr |= mpeg3demux_read_char(stream->demuxer) << 8;
stream->bfr |= mpeg3demux_read_char(stream->demuxer);
}
return mpeg3demux_eof(stream->demuxer);
}
/* Erase the buffer with the previous 4 bytes in the file. */
int mpeg3bits_refill_backwards(mpeg3_bits_t* stream)
{
stream->bit_number = 0;
stream->bfr_size = 32;
stream->bfr = mpeg3demux_read_prev_char(stream->demuxer);
stream->bfr |= (unsigned int)mpeg3demux_read_prev_char(stream->demuxer) << 8;
stream->bfr |= (unsigned int)mpeg3demux_read_prev_char(stream->demuxer) << 16;
stream->bfr |= (unsigned int)mpeg3demux_read_prev_char(stream->demuxer) << 24;
return mpeg3demux_eof(stream->demuxer);
}
int mpeg3bits_byte_align(mpeg3_bits_t *stream)
{
stream->bit_number = (stream->bit_number + 7) & 0xf8;
return 0;
}
int mpeg3bits_open_title(mpeg3_bits_t* stream, int title)
{
stream->bfr_size = stream->bit_number = 0;
return mpeg3demux_open_title(stream->demuxer, title);
}
/*
* int mpeg3bits_seek_time(mpeg3_bits_t* stream, double time_position)
* {
* stream->bfr_size = stream->bit_number = 0;
* return mpeg3demux_seek_time(stream->demuxer, time_position);
* }
*/
int mpeg3bits_seek_byte(mpeg3_bits_t* stream, int64_t position)
{
stream->bfr_size = stream->bit_number = 0;
return mpeg3demux_seek_byte(stream->demuxer, position);
}
void mpeg3bits_reset(mpeg3_bits_t *stream)
{
stream->bfr_size = stream->bit_number = 0;
}
int64_t mpeg3bits_tell(mpeg3_bits_t* stream)
{
return mpeg3demux_tell_byte(stream->demuxer);
}
int mpeg3bits_getbitoffset(mpeg3_bits_t *stream)
{
return stream->bit_number & 7;
}
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