www.pudn.com > NETVIDEO.rar > bitstream.c

#include "mpeg3private.h" 
#include "mpeg3protos.h" 
#include "bitstream.h" 
#include  
 
mpeg3_bits_t *mpeg3bits_new_stream(void) 
{ 
	mpeg3_bits_t *stream = malloc(sizeof(mpeg3_bits_t)); 
	stream->bfr = 0; 
	stream->bfr_size = 0; 
	stream->bit_number = 0; 
	stream->input_ptr = NULL; 
	return stream; 
} 
 
int mpeg3bits_delete_stream(mpeg3_bits_t* stream) 
{ 
	free(stream); 
	return 0; 
} 
 
/* 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; 
	stream->orig_ptr = buffer; 
	stream->buflen = 65535; 
	return 0; 
} 
 
int mpeg3bits_use_ptr_len(mpeg3_bits_t *stream, unsigned char *buffer, 
			  long buflen) 
{ 
  stream->bfr_size = stream->bit_number = 0; 
  stream->bfr = 0; 
  stream->input_ptr = buffer; 
  stream->orig_ptr = buffer; 
  stream->buflen = buflen; 
  return 0; 
} 
 
/* 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; 
 
	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++; 
 
	return mpeg3bits_eof(stream); 
} 
 
 
int mpeg3bits_byte_align(mpeg3_bits_t *stream) 
{ 
	stream->bit_number = (stream->bit_number + 7) & 0xf8; 
	return 0; 
} 
 
int mpeg3bits_getbitoffset(mpeg3_bits_t *stream) 
{ 
	return stream->bit_number & 7; 
}