53 lines
998 B
C
53 lines
998 B
C
|
#include "bitstream.h"
|
||
|
|
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
void bitstream_reader_init(struct bitstream_reader *r, uint8_t *data,
|
||
|
|
size_t len)
|
||
|
|
{
|
||
|
|
memset(r, 0, sizeof(struct bitstream_reader));
|
||
|
|
r->buf = data;
|
||
|
|
r->subPos = 0x80;
|
||
|
|
r->len = len;
|
||
|
|
}
|
||
|
|
|
||
|
|
uint8_t bitstream_reader_read_bit(struct bitstream_reader *r)
|
||
|
|
{
|
||
|
|
if (r->pos >= r->len)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
uint8_t bit = (*(r->buf + r->pos) & r->subPos) == r->subPos ? 1 : 0;
|
||
|
|
|
||
|
|
r->subPos >>= 0x1;
|
||
|
|
if (r->subPos == 0) {
|
||
|
|
r->subPos = 0x80;
|
||
|
|
r->pos++;
|
||
|
|
}
|
||
|
|
|
||
|
|
return bit;
|
||
|
|
}
|
||
|
|
|
||
|
|
uint8_t bitstream_reader_read_bits(struct bitstream_reader *r, int bits)
|
||
|
|
{
|
||
|
|
uint8_t res = 0;
|
||
|
|
|
||
|
|
for (int i = 1; i <= bits; i++) {
|
||
|
|
res <<= 1;
|
||
|
|
res |= bitstream_reader_read_bit(r);
|
||
|
|
}
|
||
|
|
|
||
|
|
return res;
|
||
|
|
}
|
||
|
|
|
||
|
|
uint8_t bitstream_reader_r8(struct bitstream_reader *r)
|
||
|
|
{
|
||
|
|
return bitstream_reader_read_bits(r, 8);
|
||
|
|
}
|
||
|
|
|
||
|
|
uint16_t bitstream_reader_r16(struct bitstream_reader *r)
|
||
|
|
{
|
||
|
|
uint8_t b = bitstream_reader_read_bits(r, 8);
|
||
|
|
return ((uint16_t)b << 8) | bitstream_reader_read_bits(r, 8);
|
||
|
|
}
|