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19c5fa9eea
The loop always consumes the bit read and the new bitstream reader can read 0 bits just fine.
526 lines
12 KiB
C
526 lines
12 KiB
C
/*
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* exp golomb vlc stuff
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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* Copyright (c) 2004 Alex Beregszaszi
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* @brief
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* exp golomb vlc stuff
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* @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
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*/
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#ifndef AVCODEC_GOLOMB_H
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#define AVCODEC_GOLOMB_H
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#include <stdint.h>
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#include "bitstream.h"
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#include "put_bits.h"
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#define INVALID_VLC 0x80000000
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extern const uint8_t ff_golomb_vlc_len[512];
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extern const uint8_t ff_ue_golomb_vlc_code[512];
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extern const int8_t ff_se_golomb_vlc_code[512];
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extern const uint8_t ff_ue_golomb_len[256];
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extern const uint8_t ff_interleaved_golomb_vlc_len[256];
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extern const uint8_t ff_interleaved_ue_golomb_vlc_code[256];
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extern const int8_t ff_interleaved_se_golomb_vlc_code[256];
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extern const uint8_t ff_interleaved_dirac_golomb_vlc_code[256];
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/**
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* read unsigned exp golomb code.
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*/
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static inline int get_ue_golomb(BitstreamContext *bc)
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{
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unsigned int buf;
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buf = bitstream_peek(bc, 32);
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if (buf >= (1 << 27)) {
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buf >>= 32 - 9;
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bitstream_skip(bc, ff_golomb_vlc_len[buf]);
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return ff_ue_golomb_vlc_code[buf];
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} else {
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int log = 2 * av_log2(buf) - 31;
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buf >>= log;
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buf--;
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bitstream_skip(bc, 32 - log);
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return buf;
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}
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}
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/**
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* Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
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*/
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static inline unsigned get_ue_golomb_long(BitstreamContext *bc)
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{
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unsigned buf, log;
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buf = bitstream_peek(bc, 32);
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log = 31 - av_log2(buf);
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bitstream_skip(bc, log);
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return bitstream_read(bc, log + 1) - 1;
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}
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/**
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* read unsigned exp golomb code, constraint to a max of 31.
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* the return value is undefined if the stored value exceeds 31.
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*/
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static inline int get_ue_golomb_31(BitstreamContext *bc)
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{
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unsigned int buf;
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buf = bitstream_peek(bc, 32);
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buf >>= 32 - 9;
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bitstream_skip(bc, ff_golomb_vlc_len[buf]);
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return ff_ue_golomb_vlc_code[buf];
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}
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static inline unsigned get_interleaved_ue_golomb(BitstreamContext *bc)
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{
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uint32_t buf;
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buf = bitstream_peek(bc, 32);
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if (buf & 0xAA800000) {
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buf >>= 32 - 8;
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bitstream_skip(bc, ff_interleaved_golomb_vlc_len[buf]);
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return ff_interleaved_ue_golomb_vlc_code[buf];
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} else {
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unsigned ret = 1;
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do {
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buf >>= 32 - 8;
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bitstream_skip(bc, FFMIN(ff_interleaved_golomb_vlc_len[buf], 8));
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if (ff_interleaved_golomb_vlc_len[buf] != 9) {
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ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1;
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ret |= ff_interleaved_dirac_golomb_vlc_code[buf];
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break;
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}
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ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf];
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buf = bitstream_peek(bc, 32);
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} while (bitstream_bits_left(bc) > 0);
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return ret - 1;
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}
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}
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/**
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* read unsigned truncated exp golomb code.
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*/
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static inline int get_te0_golomb(BitstreamContext *bc, int range)
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{
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assert(range >= 1);
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if (range == 1)
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return 0;
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else if (range == 2)
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return bitstream_read_bit(bc) ^ 1;
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else
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return get_ue_golomb(bc);
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}
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/**
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* read unsigned truncated exp golomb code.
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*/
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static inline int get_te_golomb(BitstreamContext *bc, int range)
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{
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assert(range >= 1);
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if (range == 2)
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return bitstream_read_bit(bc) ^ 1;
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else
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return get_ue_golomb(bc);
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}
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/**
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* read signed exp golomb code.
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*/
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static inline int get_se_golomb(BitstreamContext *bc)
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{
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unsigned int buf;
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buf = bitstream_peek(bc, 32);
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if (buf >= (1 << 27)) {
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buf >>= 32 - 9;
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bitstream_skip(bc, ff_golomb_vlc_len[buf]);
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return ff_se_golomb_vlc_code[buf];
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} else {
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int log = 2 * av_log2(buf) - 31;
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buf >>= log;
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bitstream_skip(bc, 32 - log);
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if (buf & 1)
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buf = -(buf >> 1);
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else
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buf = (buf >> 1);
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return buf;
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}
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}
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static inline int get_se_golomb_long(BitstreamContext *bc)
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{
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unsigned int buf = get_ue_golomb_long(bc);
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if (buf & 1)
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buf = (buf + 1) >> 1;
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else
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buf = -(buf >> 1);
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return buf;
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}
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static inline int get_interleaved_se_golomb(BitstreamContext *bc)
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{
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unsigned int buf;
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buf = bitstream_peek(bc, 32);
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if (buf & 0xAA800000) {
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buf >>= 32 - 8;
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bitstream_skip(bc, ff_interleaved_golomb_vlc_len[buf]);
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return ff_interleaved_se_golomb_vlc_code[buf];
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} else {
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int log;
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bitstream_skip(bc, 8);
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buf |= 1 | bitstream_peek(bc, 24);
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if ((buf & 0xAAAAAAAA) == 0)
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return INVALID_VLC;
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for (log = 31; (buf & 0x80000000) == 0; log--)
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buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
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bitstream_skip(bc, 63 - 2 * log - 8);
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return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
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}
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}
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static inline int dirac_get_se_golomb(BitstreamContext *bc)
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{
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uint32_t ret = get_interleaved_ue_golomb(bc);
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if (ret) {
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uint32_t buf;
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buf = bitstream_read_signed(bc, 1);
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ret = (ret ^ buf) - buf;
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}
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return ret;
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}
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/**
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* read unsigned golomb rice code (ffv1).
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*/
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static inline int get_ur_golomb(BitstreamContext *bc, int k, int limit,
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int esc_len)
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{
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unsigned int buf;
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int log;
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buf = bitstream_peek(bc, 32);
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log = av_log2(buf);
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if (log > 31 - limit) {
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buf >>= log - k;
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buf += (30 - log) << k;
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bitstream_skip(bc, 32 + k - log);
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return buf;
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} else {
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bitstream_skip(bc, limit);
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buf = bitstream_read(bc, esc_len);
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return buf + limit - 1;
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}
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}
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/**
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* read unsigned golomb rice code (jpegls).
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*/
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static inline int get_ur_golomb_jpegls(BitstreamContext *bc, int k, int limit,
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int esc_len)
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{
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unsigned int buf;
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int log;
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buf = bitstream_peek(bc, 32);
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log = av_log2(buf);
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if (log - k >= 1 && 32 - log < limit) {
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buf >>= log - k;
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buf += (30 - log) << k;
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bitstream_skip(bc, 32 + k - log);
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return buf;
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} else {
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int i;
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for (i = 0;
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i < limit && bitstream_read_bit(bc) == 0 && bitstream_bits_left(bc) > 0;
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i++);
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if (i < limit - 1) {
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buf = bitstream_read(bc, k);
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return buf + (i << k);
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} else if (i == limit - 1) {
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buf = bitstream_read(bc, esc_len);
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return buf + 1;
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} else
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return -1;
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}
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}
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/**
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* read signed golomb rice code (ffv1).
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*/
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static inline int get_sr_golomb(BitstreamContext *bc, int k, int limit,
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int esc_len)
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{
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int v = get_ur_golomb(bc, k, limit, esc_len);
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v++;
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if (v & 1)
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return v >> 1;
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else
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return -(v >> 1);
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// return (v>>1) ^ -(v&1);
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}
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/**
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* read signed golomb rice code (flac).
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*/
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static inline int get_sr_golomb_flac(BitstreamContext *bc, int k, int limit,
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int esc_len)
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{
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int v = get_ur_golomb_jpegls(bc, k, limit, esc_len);
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return (v >> 1) ^ -(v & 1);
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}
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/**
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* read unsigned golomb rice code (shorten).
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*/
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static inline unsigned int get_ur_golomb_shorten(BitstreamContext *bc, int k)
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{
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return get_ur_golomb_jpegls(bc, k, INT_MAX, 0);
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}
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/**
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* read signed golomb rice code (shorten).
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*/
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static inline int get_sr_golomb_shorten(BitstreamContext *bc, int k)
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{
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int uvar = get_ur_golomb_jpegls(bc, k + 1, INT_MAX, 0);
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if (uvar & 1)
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return ~(uvar >> 1);
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else
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return uvar >> 1;
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}
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#ifdef TRACE
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static inline int get_ue(BitstreamContext *s, const char *file, const char *func,
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int line)
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{
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int show = bitstream_peek(s, 24);
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int pos = bitstream_tell(s);
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int i = get_ue_golomb(s);
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int len = bitstream_tell(s) - pos;
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int bits = show >> (24 - len);
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av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d ue @%5d in %s %s:%d\n",
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bits, len, i, pos, file, func, line);
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return i;
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}
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static inline int get_se(BitstreamContext *s, const char *file, const char *func,
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int line)
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{
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int show = bitstream_peek(s, 24);
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int pos = bitstream_tell(s);
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int i = get_se_golomb(s);
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int len = bitstream_tell(s) - pos;
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int bits = show >> (24 - len);
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av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d se @%5d in %s %s:%d\n",
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bits, len, i, pos, file, func, line);
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return i;
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}
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static inline int get_te(BitstreamContext *s, int r, char *file, const char *func,
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int line)
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{
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int show = bitstream_peek(s, 24);
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int pos = bitstream_tell(s);
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int i = get_te0_golomb(s, r);
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int len = bitstream_tell(s) - pos;
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int bits = show >> (24 - len);
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av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d te @%5d in %s %s:%d\n",
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bits, len, i, pos, file, func, line);
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return i;
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}
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#define get_ue_golomb(a) get_ue(a, __FILE__, __func__, __LINE__)
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#define get_se_golomb(a) get_se(a, __FILE__, __func__, __LINE__)
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#define get_te_golomb(a, r) get_te(a, r, __FILE__, __func__, __LINE__)
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#define get_te0_golomb(a, r) get_te(a, r, __FILE__, __func__, __LINE__)
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#endif /* TRACE */
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/**
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* write unsigned exp golomb code.
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*/
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static inline void set_ue_golomb(PutBitContext *pb, int i)
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{
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assert(i >= 0);
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if (i < 256)
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put_bits(pb, ff_ue_golomb_len[i], i + 1);
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else {
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int e = av_log2(i + 1);
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put_bits(pb, 2 * e + 1, i + 1);
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}
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}
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/**
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* write truncated unsigned exp golomb code.
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*/
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static inline void set_te_golomb(PutBitContext *pb, int i, int range)
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{
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assert(range >= 1);
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assert(i <= range);
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if (range == 2)
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put_bits(pb, 1, i ^ 1);
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else
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set_ue_golomb(pb, i);
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}
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/**
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* write signed exp golomb code. 16 bits at most.
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*/
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static inline void set_se_golomb(PutBitContext *pb, int i)
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{
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i = 2 * i - 1;
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if (i < 0)
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i ^= -1; //FIXME check if gcc does the right thing
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set_ue_golomb(pb, i);
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}
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/**
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* write unsigned golomb rice code (ffv1).
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*/
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static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit,
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int esc_len)
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{
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int e;
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assert(i >= 0);
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e = i >> k;
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if (e < limit)
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put_bits(pb, e + k + 1, (1 << k) + (i & ((1 << k) - 1)));
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else
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put_bits(pb, limit + esc_len, i - limit + 1);
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}
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/**
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* write unsigned golomb rice code (jpegls).
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*/
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static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k,
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int limit, int esc_len)
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{
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int e;
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assert(i >= 0);
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e = (i >> k) + 1;
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if (e < limit) {
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while (e > 31) {
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put_bits(pb, 31, 0);
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e -= 31;
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}
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put_bits(pb, e, 1);
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if (k)
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put_sbits(pb, k, i);
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} else {
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while (limit > 31) {
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put_bits(pb, 31, 0);
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limit -= 31;
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}
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put_bits(pb, limit, 1);
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put_bits(pb, esc_len, i - 1);
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}
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}
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/**
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* write signed golomb rice code (ffv1).
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*/
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static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit,
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int esc_len)
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{
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int v;
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v = -2 * i - 1;
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v ^= (v >> 31);
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set_ur_golomb(pb, v, k, limit, esc_len);
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}
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/**
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* write signed golomb rice code (flac).
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*/
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static inline void set_sr_golomb_flac(PutBitContext *pb, int i, int k,
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int limit, int esc_len)
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{
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int v;
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v = -2 * i - 1;
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v ^= (v >> 31);
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set_ur_golomb_jpegls(pb, v, k, limit, esc_len);
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}
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#endif /* AVCODEC_GOLOMB_H */
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