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/* kate: tab-indent on; indent-width 4; mixedindent off; indent-mode cstyle; remove-trailing-space on; */
#ifndef ALTERH264_BITS_READER_H
#define ALTERH264_BITS_READER_H
#include <sys/types.h>
#include <inttypes.h>
#include <stdio.h>
typedef struct {
uint8_t *buffer, *start;
int offbits, length, oflow;
} bits_reader_t;
static void
bits_reader_set (bits_reader_t * br, uint8_t * buf, int len)
{
br->buffer = br->start = buf;
br->offbits = 0;
br->length = len;
br->oflow = 0;
}
static inline uint32_t
more_rbsp_data (bits_reader_t * br)
{
uint8_t val[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 };
uint8_t *buf = br->start + br->length;
int bit;
while (--buf >= br->buffer)
{
for (bit = 7; bit > -1; bit--)
if (*buf & val[bit])
return ((buf - br->buffer) * 8) - br->offbits + bit;
}
return 0;
}
static inline uint8_t
bits_reader_shift (bits_reader_t * br)
{
br->offbits = 0;
if ((br->buffer + 1) > (br->start + br->length - 1))
{
br->oflow = 1;
//printf("!!!!! buffer overflow !!!!!\n");
return 0;
}
++br->buffer;
if ((*(br->buffer) == 3) && ((br->buffer - br->start) > 2)
&& (*(br->buffer - 2) == 0) && (*(br->buffer - 1) == 0))
{
if ((br->buffer + 1) > (br->start + br->length - 1))
{
br->oflow = 1;
//printf("!!!!! buffer overflow !!!!!\n");
return 0;
}
++br->buffer;
}
return 1;
}
static inline uint32_t
read_bits (bits_reader_t * br, int nbits)
{
uint8_t val[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 };
uint32_t res = 0;
while (nbits)
{
res = (res << 1) + ((*br->buffer & val[br->offbits]) ? 1 : 0);
--nbits;
++br->offbits;
if (br->offbits > 7)
if (!bits_reader_shift (br))
return 1;
}
return res;
}
static inline void
skip_bits (bits_reader_t * br, int nbits)
{
while (nbits)
{
--nbits;
++br->offbits;
if (br->offbits > 7)
bits_reader_shift (br);
}
}
static inline uint32_t
read_exp_ue (bits_reader_t * br)
{
int leading = -1;
uint8_t b;
for (b = 0; !b; leading++)
b = read_bits (br, 1);
return (1 << leading) - 1 + read_bits (br, leading);
}
static inline int32_t
read_exp_se (bits_reader_t * br)
{
uint32_t res = read_exp_ue (br);
return (res & 0x01) ? (res + 1) / 2 : -(res / 2);
}
#endif /* ALTERH264_BITS_READER_H */
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