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/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_GOLOMB_BS_H
#define AVCODEC_GOLOMB_BS_H
#include <stdint.h>
#include "bitstream.h"
#include "golomb_common.h"
/**
* Read an unsigned Exp-Golomb code in the range 0 to 8190.
*
* @returns the read value or a negative error code.
*/
static inline int golomb_bs_get_ue(BitstreamContext *bc)
{
unsigned int buf = bitstream_peek(bc, 32);
if (buf >= (1 << 27)) {
buf >>= 32 - 9;
bitstream_skip_cache(bc, ff_golomb_vlc_len[buf]);
return ff_ue_golomb_vlc_code[buf];
} else {
int log = 2 * av_log2(buf) - 31;
bitstream_skip_cache(bc, 32 - log);
if (log < 7)
return AVERROR_INVALIDDATA;
buf >>= log;
buf--;
return buf;
}
}
/**
* Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
*/
static inline unsigned golomb_bs_get_ue_long(BitstreamContext *bc)
{
unsigned int buf = bitstream_peek(bc, 32);
unsigned int log = 31 - av_log2(buf);
bitstream_skip_cache(bc, log);
return bitstream_read(bc, log + 1) - 1;
}
/**
* read unsigned exp golomb code, constraint to a max of 31.
* If the value encountered is not in 0..31, the return value
* is outside the range 0..30.
*/
static inline int golomb_bs_get_ue_31(BitstreamContext *bc)
{
unsigned int buf = bitstream_peek(bc, 32);
buf >>= 32 - 9;
bitstream_skip_cache(bc, ff_golomb_vlc_len[buf]);
return ff_ue_golomb_vlc_code[buf];
}
static inline unsigned golomb_bs_get_ue_interleaved(BitstreamContext *bc)
{
uint32_t buf = bitstream_peek(bc, 32);
if (buf & 0xAA800000) {
buf >>= 32 - 8;
bitstream_skip_cache(bc, ff_interleaved_golomb_vlc_len[buf]);
return ff_interleaved_ue_golomb_vlc_code[buf];
} else {
unsigned ret = 1;
do {
buf >>= 32 - 8;
bitstream_skip_cache(bc, FFMIN(ff_interleaved_golomb_vlc_len[buf], 8));
if (ff_interleaved_golomb_vlc_len[buf] != 9) {
ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1;
ret |= ff_interleaved_dirac_golomb_vlc_code[buf];
break;
}
ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf];
buf = bitstream_peek(bc, 32);
} while (bitstream_bits_left(bc) > 0);
return ret - 1;
}
}
/**
* read unsigned truncated exp golomb code.
*/
static inline int golomb_bs_get_te0(BitstreamContext *bc, int range)
{
av_assert2(range >= 1);
if (range == 1)
return 0;
else if (range == 2)
return bitstream_read(bc, 1) ^ 1;
else
return golomb_bs_get_ue(bc);
}
/**
* read unsigned truncated exp golomb code.
*/
static inline int golomb_bs_get_te(BitstreamContext *bc, int range)
{
av_assert2(range >= 1);
if (range == 2)
return bitstream_read(bc, 1) ^ 1;
else
return golomb_bs_get_ue(bc);
}
/**
* read signed exp golomb code.
*/
static inline int golomb_bs_get_se(BitstreamContext *bc)
{
unsigned int buf;
buf = bitstream_peek(bc, 32);
if (buf >= (1 << 27)) {
buf >>= 32 - 9;
bitstream_skip_cache(bc, ff_golomb_vlc_len[buf]);
return ff_se_golomb_vlc_code[buf];
} else {
int log = 2 * av_log2(buf) - 31;
buf >>= log;
bitstream_skip_cache(bc, 32 - log);
if (buf & 1)
buf = -(buf >> 1);
else
buf = (buf >> 1);
return buf;
}
}
static inline int golomb_bs_get_se_long(BitstreamContext *bc)
{
unsigned int buf = golomb_bs_get_ue_long(bc);
int sign = (buf & 1) - 1;
return ((buf >> 1) ^ sign) + 1;
}
static inline int golomb_bs_get_se_interleaved(BitstreamContext *bc)
{
unsigned int buf;
buf = bitstream_peek(bc, 32);
if (buf & 0xAA800000) {
buf >>= 32 - 8;
bitstream_skip_cache(bc, ff_interleaved_golomb_vlc_len[buf]);
return ff_interleaved_se_golomb_vlc_code[buf];
} else {
int log;
bitstream_skip_cache(bc, 8);
buf |= 1 | bitstream_peek(bc, 24);
if ((buf & 0xAAAAAAAA) == 0)
return INVALID_VLC;
for (log = 31; (buf & 0x80000000) == 0; log--)
buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
bitstream_skip(bc, 63 - 2 * log - 8);
return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
}
}
static inline int golomb_bs_get_se_dirac(BitstreamContext *bc)
{
uint32_t ret = golomb_bs_get_ue_interleaved(bc);
if (ret) {
int sign = -bitstream_read(bc, 1);
ret = (ret ^ sign) - sign;
}
return ret;
}
/**
* read unsigned golomb rice code (ffv1).
*/
static inline int golomb_bs_get_ur(BitstreamContext *bc, int k, int limit,
int esc_len)
{
unsigned int buf;
int log;
buf = bitstream_peek(bc, 32);
log = av_log2(buf);
if (log > 31 - limit) {
buf >>= log - k;
buf += (30 - log) << k;
bitstream_skip(bc, 32 + k - log);
return buf;
} else {
bitstream_skip(bc, limit);
buf = bitstream_read(bc, esc_len);
return buf + limit - 1;
}
}
/**
* read unsigned golomb rice code (jpegls).
*/
static inline int golomb_bs_get_ur_jpegls(BitstreamContext *bc, int k, int limit,
int esc_len)
{
unsigned int buf;
int log;
buf = bitstream_peek(bc, 32);
log = av_log2(buf);
if (log - k >= 1 && 32 - log < limit) {
buf >>= log - k;
buf += (30 - log) << k;
bitstream_skip(bc, 32 + k - log);
return buf;
} else {
int i;
for (i = 0;
i < limit && bitstream_peek(bc, 1) == 0 && bitstream_bits_left(bc) > 0;
i++)
bitstream_skip_cache(bc, 1);
bitstream_skip(bc, 1);
if (i < limit - 1) {
buf = bitstream_read(bc, k);
return buf + (i << k);
} else if (i == limit - 1) {
buf = bitstream_read(bc, esc_len);
return buf + 1;
} else
return -1;
}
}
/**
* read signed golomb rice code (ffv1).
*/
static inline int golomb_bs_get_sr(BitstreamContext *bc, int k, int limit,
int esc_len)
{
unsigned v = golomb_bs_get_ur(bc, k, limit, esc_len);
return (v >> 1) ^ -(v & 1);
}
/**
* read signed golomb rice code (flac).
*/
static inline int golomb_bs_get_sr_flac(BitstreamContext *bc, int k, int limit,
int esc_len)
{
unsigned v = golomb_bs_get_ur_jpegls(bc, k, limit, esc_len);
return (v >> 1) ^ -(v & 1);
}
/**
* read unsigned golomb rice code (shorten).
*/
static inline unsigned int golomb_bs_get_ur_shorten(BitstreamContext *bc, int k)
{
return golomb_bs_get_ur_jpegls(bc, k, INT_MAX, 0);
}
/**
* read signed golomb rice code (shorten).
*/
static inline int golomb_bs_get_sr_shorten(BitstreamContext *bc, int k)
{
int uvar = golomb_bs_get_ur_jpegls(bc, k + 1, INT_MAX, 0);
return (uvar >> 1) ^ -(uvar & 1);
}
#endif /* AVCODEC_GOLOMB_BS_H */
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