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FFmpeg/libavcodec/golomb.h
Andreas Rheinhardt 2b541b8c1d avcodec/golomb: Factor writing golomb codes out 
Most users only want to either read or write golomb codes, not both.
By splitting these headers one avoids having unnecesssary
(get|put)_hits.h inclusions.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-01-06 08:28:02 +01:00

617 lines
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/*
* exp golomb vlc stuff
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
* Copyright (c) 2004 Alex Beregszaszi
*
* 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
*/
/**
* @file
* @brief
* exp golomb vlc stuff
* @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
*/
#ifndef AVCODEC_GOLOMB_H
#define AVCODEC_GOLOMB_H
#include <stdint.h>
#include "get_bits.h"
#define INVALID_VLC 0x80000000
extern const uint8_t ff_golomb_vlc_len[512];
extern const uint8_t ff_ue_golomb_vlc_code[512];
extern const int8_t ff_se_golomb_vlc_code[512];
extern const uint8_t ff_interleaved_golomb_vlc_len[256];
extern const uint8_t ff_interleaved_ue_golomb_vlc_code[256];
extern const int8_t ff_interleaved_se_golomb_vlc_code[256];
extern const uint8_t ff_interleaved_dirac_golomb_vlc_code[256];
/**
* Read an unsigned Exp-Golomb code in the range 0 to 8190.
*
* @returns the read value or a negative error code.
*/
static inline int get_ue_golomb(GetBitContext *gb)
{
unsigned int buf;
#if CACHED_BITSTREAM_READER
buf = show_bits_long(gb, 32);
if (buf >= (1 << 27)) {
buf >>= 32 - 9;
skip_bits_long(gb, ff_golomb_vlc_len[buf]);
return ff_ue_golomb_vlc_code[buf];
} else {
int log = 2 * av_log2(buf) - 31;
skip_bits_long(gb, 32 - log);
if (log < 7)
return AVERROR_INVALIDDATA;
buf >>= log;
buf--;
return buf;
}
#else
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
if (buf >= (1 << 27)) {
buf >>= 32 - 9;
LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_ue_golomb_vlc_code[buf];
} else {
int log = 2 * av_log2(buf) - 31;
LAST_SKIP_BITS(re, gb, 32 - log);
CLOSE_READER(re, gb);
if (log < 7)
return AVERROR_INVALIDDATA;
buf >>= log;
buf--;
return buf;
}
#endif
}
/**
* Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
*/
static inline unsigned get_ue_golomb_long(GetBitContext *gb)
{
unsigned buf, log;
buf = show_bits_long(gb, 32);
log = 31 - av_log2(buf);
skip_bits_long(gb, log);
return get_bits_long(gb, 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 get_ue_golomb_31(GetBitContext *gb)
{
unsigned int buf;
#if CACHED_BITSTREAM_READER
buf = show_bits_long(gb, 32);
buf >>= 32 - 9;
skip_bits_long(gb, ff_golomb_vlc_len[buf]);
#else
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
buf >>= 32 - 9;
LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
#endif
return ff_ue_golomb_vlc_code[buf];
}
static inline unsigned get_interleaved_ue_golomb(GetBitContext *gb)
{
uint32_t buf;
#if CACHED_BITSTREAM_READER
buf = show_bits_long(gb, 32);
if (buf & 0xAA800000) {
buf >>= 32 - 8;
skip_bits_long(gb, ff_interleaved_golomb_vlc_len[buf]);
return ff_interleaved_ue_golomb_vlc_code[buf];
} else {
unsigned ret = 1;
do {
buf >>= 32 - 8;
skip_bits_long(gb, 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 = show_bits_long(gb, 32);
} while (get_bits_left(gb) > 0);
return ret - 1;
}
#else
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
if (buf & 0xAA800000) {
buf >>= 32 - 8;
LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_interleaved_ue_golomb_vlc_code[buf];
} else {
unsigned ret = 1;
do {
buf >>= 32 - 8;
LAST_SKIP_BITS(re, gb,
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];
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
} while (ret<0x8000000U && BITS_AVAILABLE(re, gb));
CLOSE_READER(re, gb);
return ret - 1;
}
#endif
}
/**
* read unsigned truncated exp golomb code.
*/
static inline int get_te0_golomb(GetBitContext *gb, int range)
{
av_assert2(range >= 1);
if (range == 1)
return 0;
else if (range == 2)
return get_bits1(gb) ^ 1;
else
return get_ue_golomb(gb);
}
/**
* read unsigned truncated exp golomb code.
*/
static inline int get_te_golomb(GetBitContext *gb, int range)
{
av_assert2(range >= 1);
if (range == 2)
return get_bits1(gb) ^ 1;
else
return get_ue_golomb(gb);
}
/**
* read signed exp golomb code.
*/
static inline int get_se_golomb(GetBitContext *gb)
{
unsigned int buf;
#if CACHED_BITSTREAM_READER
buf = show_bits_long(gb, 32);
if (buf >= (1 << 27)) {
buf >>= 32 - 9;
skip_bits_long(gb, ff_golomb_vlc_len[buf]);
return ff_se_golomb_vlc_code[buf];
} else {
int log = 2 * av_log2(buf) - 31;
buf >>= log;
skip_bits_long(gb, 32 - log);
if (buf & 1)
buf = -(buf >> 1);
else
buf = (buf >> 1);
return buf;
}
#else
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
if (buf >= (1 << 27)) {
buf >>= 32 - 9;
LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_se_golomb_vlc_code[buf];
} else {
int log = av_log2(buf), sign;
LAST_SKIP_BITS(re, gb, 31 - log);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
buf >>= log;
LAST_SKIP_BITS(re, gb, 32 - log);
CLOSE_READER(re, gb);
sign = -(buf & 1);
buf = ((buf >> 1) ^ sign) - sign;
return buf;
}
#endif
}
static inline int get_se_golomb_long(GetBitContext *gb)
{
unsigned int buf = get_ue_golomb_long(gb);
int sign = (buf & 1) - 1;
return ((buf >> 1) ^ sign) + 1;
}
static inline int get_interleaved_se_golomb(GetBitContext *gb)
{
unsigned int buf;
#if CACHED_BITSTREAM_READER
buf = show_bits_long(gb, 32);
if (buf & 0xAA800000) {
buf >>= 32 - 8;
skip_bits_long(gb, ff_interleaved_golomb_vlc_len[buf]);
return ff_interleaved_se_golomb_vlc_code[buf];
} else {
int log;
skip_bits(gb, 8);
buf |= 1 | show_bits(gb, 24);
if ((buf & 0xAAAAAAAA) == 0)
return INVALID_VLC;
for (log = 31; (buf & 0x80000000) == 0; log--)
buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
skip_bits_long(gb, 63 - 2 * log - 8);
return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
}
#else
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
if (buf & 0xAA800000) {
buf >>= 32 - 8;
LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_interleaved_se_golomb_vlc_code[buf];
} else {
int log;
LAST_SKIP_BITS(re, gb, 8);
UPDATE_CACHE(re, gb);
buf |= 1 | (GET_CACHE(re, gb) >> 8);
if ((buf & 0xAAAAAAAA) == 0)
return INVALID_VLC;
for (log = 31; (buf & 0x80000000) == 0; log--)
buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
LAST_SKIP_BITS(re, gb, 63 - 2 * log - 8);
CLOSE_READER(re, gb);
return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
}
#endif
}
static inline int dirac_get_se_golomb(GetBitContext *gb)
{
uint32_t ret = get_interleaved_ue_golomb(gb);
if (ret) {
int sign = -get_bits1(gb);
ret = (ret ^ sign) - sign;
}
return ret;
}
/**
* read unsigned golomb rice code (ffv1).
*/
static inline int get_ur_golomb(GetBitContext *gb, int k, int limit,
int esc_len)
{
unsigned int buf;
int log;
#if CACHED_BITSTREAM_READER
buf = show_bits_long(gb, 32);
log = av_log2(buf);
if (log > 31 - limit) {
buf >>= log - k;
buf += (30 - log) << k;
skip_bits_long(gb, 32 + k - log);
return buf;
} else {
skip_bits_long(gb, limit);
buf = get_bits_long(gb, esc_len);
return buf + limit - 1;
}
#else
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
log = av_log2(buf);
if (log > 31 - limit) {
buf >>= log - k;
buf += (30U - log) << k;
LAST_SKIP_BITS(re, gb, 32 + k - log);
CLOSE_READER(re, gb);
return buf;
} else {
LAST_SKIP_BITS(re, gb, limit);
UPDATE_CACHE(re, gb);
buf = SHOW_UBITS(re, gb, esc_len);
LAST_SKIP_BITS(re, gb, esc_len);
CLOSE_READER(re, gb);
return buf + limit - 1;
}
#endif
}
/**
* read unsigned golomb rice code (jpegls).
*/
static inline int get_ur_golomb_jpegls(GetBitContext *gb, int k, int limit,
int esc_len)
{
unsigned int buf;
int log;
#if CACHED_BITSTREAM_READER
buf = show_bits_long(gb, 32);
log = av_log2(buf);
if (log - k >= 1 && 32 - log < limit) {
buf >>= log - k;
buf += (30 - log) << k;
skip_bits_long(gb, 32 + k - log);
return buf;
} else {
int i;
for (i = 0;
i < limit && get_bits1(gb) == 0 && get_bits_left(gb) > 0;
i++);
if (i < limit - 1) {
buf = get_bits_long(gb, k);
return buf + (i << k);
} else if (i == limit - 1) {
buf = get_bits_long(gb, esc_len);
return buf + 1;
} else
return -1;
}
#else
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
log = av_log2(buf);
av_assert2(k <= 31);
if (log - k >= 32 - MIN_CACHE_BITS + (MIN_CACHE_BITS == 32) &&
32 - log < limit) {
buf >>= log - k;
buf += (30U - log) << k;
LAST_SKIP_BITS(re, gb, 32 + k - log);
CLOSE_READER(re, gb);
return buf;
} else {
int i;
for (i = 0; i + MIN_CACHE_BITS <= limit && SHOW_UBITS(re, gb, MIN_CACHE_BITS) == 0; i += MIN_CACHE_BITS) {
if (gb->size_in_bits <= re_index) {
CLOSE_READER(re, gb);
return -1;
}
LAST_SKIP_BITS(re, gb, MIN_CACHE_BITS);
UPDATE_CACHE(re, gb);
}
for (; i < limit && SHOW_UBITS(re, gb, 1) == 0; i++) {
SKIP_BITS(re, gb, 1);
}
LAST_SKIP_BITS(re, gb, 1);
UPDATE_CACHE(re, gb);
if (i < limit - 1) {
if (k) {
if (k > MIN_CACHE_BITS - 1) {
buf = SHOW_UBITS(re, gb, 16) << (k-16);
LAST_SKIP_BITS(re, gb, 16);
UPDATE_CACHE(re, gb);
buf |= SHOW_UBITS(re, gb, k-16);
LAST_SKIP_BITS(re, gb, k-16);
} else {
buf = SHOW_UBITS(re, gb, k);
LAST_SKIP_BITS(re, gb, k);
}
} else {
buf = 0;
}
buf += ((SUINT)i << k);
} else if (i == limit - 1) {
buf = SHOW_UBITS(re, gb, esc_len);
LAST_SKIP_BITS(re, gb, esc_len);
buf ++;
} else {
buf = -1;
}
CLOSE_READER(re, gb);
return buf;
}
#endif
}
/**
* read signed golomb rice code (ffv1).
*/
static inline int get_sr_golomb(GetBitContext *gb, int k, int limit,
int esc_len)
{
unsigned v = get_ur_golomb(gb, k, limit, esc_len);
return (v >> 1) ^ -(v & 1);
}
/**
* read signed golomb rice code (flac).
*/
static inline int get_sr_golomb_flac(GetBitContext *gb, int k, int limit,
int esc_len)
{
unsigned v = get_ur_golomb_jpegls(gb, k, limit, esc_len);
return (v >> 1) ^ -(v & 1);
}
/**
* read unsigned golomb rice code (shorten).
*/
static inline unsigned int get_ur_golomb_shorten(GetBitContext *gb, int k)
{
return get_ur_golomb_jpegls(gb, k, INT_MAX, 0);
}
/**
* read signed golomb rice code (shorten).
*/
static inline int get_sr_golomb_shorten(GetBitContext *gb, int k)
{
int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0);
return (uvar >> 1) ^ -(uvar & 1);
}
#ifdef TRACE
static inline int get_ue(GetBitContext *s, const char *file, const char *func,
int line)
{
int show = show_bits(s, 24);
int pos = get_bits_count(s);
int i = get_ue_golomb(s);
int len = get_bits_count(s) - pos;
int bits = show >> (24 - len);
av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d ue @%5d in %s %s:%d\n",
bits, len, i, pos, file, func, line);
return i;
}
static inline int get_se(GetBitContext *s, const char *file, const char *func,
int line)
{
int show = show_bits(s, 24);
int pos = get_bits_count(s);
int i = get_se_golomb(s);
int len = get_bits_count(s) - pos;
int bits = show >> (24 - len);
av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d se @%5d in %s %s:%d\n",
bits, len, i, pos, file, func, line);
return i;
}
static inline int get_te(GetBitContext *s, int r, char *file, const char *func,
int line)
{
int show = show_bits(s, 24);
int pos = get_bits_count(s);
int i = get_te0_golomb(s, r);
int len = get_bits_count(s) - pos;
int bits = show >> (24 - len);
av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d te @%5d in %s %s:%d\n",
bits, len, i, pos, file, func, line);
return i;
}
#define get_ue_golomb(a) get_ue(a, __FILE__, __func__, __LINE__)
#define get_se_golomb(a) get_se(a, __FILE__, __func__, __LINE__)
#define get_te_golomb(a, r) get_te(a, r, __FILE__, __func__, __LINE__)
#define get_te0_golomb(a, r) get_te(a, r, __FILE__, __func__, __LINE__)
#endif /* TRACE */
#endif /* AVCODEC_GOLOMB_H */
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