/* * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> * * 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 * Context Adaptive Binary Arithmetic Coder inline functions */ #ifndef AVCODEC_CABAC_FUNCTIONS_H#define AVCODEC_CABAC_FUNCTIONS_H #include <stddef.h>#include <stdint.h> #include "libavutil/attributes.h"#include "libavutil/intmath.h"#include "cabac.h"#include "config.h" #ifndef UNCHECKED_BITSTREAM_READER#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER#endif #if ARCH_AARCH64#   include "aarch64/cabac.h"#endif#if ARCH_ARM#   include "arm/cabac.h"#endif#if ARCH_X86#   include "x86/cabac.h"#endif#if ARCH_MIPS#   include "mips/cabac.h"#endif#if ARCH_LOONGARCH64#   include "loongarch/cabac.h"#endif static const uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;static const uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;static const uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;static const uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET; #if !defined(get_cabac_bypass) || !defined(get_cabac_terminate)static void refill(CABACContext *c){#if CABAC_BITS == 16        c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);#else        c->low+= c->bytestream[0]<<1;#endif    c->low -= CABAC_MASK;#if !UNCHECKED_BITSTREAM_READER    if (c->bytestream < c->bytestream_end)#endif        c->bytestream += CABAC_BITS / 8;}#endif #ifndef get_cabac_terminatestatic inline void renorm_cabac_decoder_once(CABACContext *c){    int shift= (uint32_t)(c->range - 0x100)>>31;    c->range<<= shift;    c->low  <<= shift;    if(!(c->low & CABAC_MASK))        refill(c);}#endif #ifndef get_cabac_inlinestatic void refill2(CABACContext *c){    int i;    unsigned x;#if !HAVE_FAST_CLZ    x= c->low ^ (c->low-1);    i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];#else    i = ff_ctz(c->low) - CABAC_BITS;#endif     x= -CABAC_MASK; #if CABAC_BITS == 16        x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);#else        x+= c->bytestream[0]<<1;#endif     c->low += x<<i;#if !UNCHECKED_BITSTREAM_READER    if (c->bytestream < c->bytestream_end)#endif        c->bytestream += CABAC_BITS/8;}#endif #ifndef get_cabac_inlinestatic av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){    int s = *state;    int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];    int bit, lps_mask;     c->range -= RangeLPS;    lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;     c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;    c->range += (RangeLPS - c->range) & lps_mask;     s^=lps_mask;    *state= (ff_h264_mlps_state+128)[s];    bit= s&1;     lps_mask= ff_h264_norm_shift[c->range];    c->range<<= lps_mask;    c->low  <<= lps_mask;    if(!(c->low & CABAC_MASK))        refill2(c);    return bit;}#endif static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){    return get_cabac_inline(c,state);} static int av_unused get_cabac(CABACContext *c, uint8_t * const state){    return get_cabac_inline(c,state);} #ifndef get_cabac_bypassstatic int av_unused get_cabac_bypass(CABACContext *c){    int range;    c->low += c->low;     if(!(c->low & CABAC_MASK))        refill(c);     range= c->range<<(CABAC_BITS+1);    if(c->low < range){        return 0;    }else{        c->low -= range;        return 1;    }}#endif #ifndef get_cabac_bypass_signstatic av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){    int range, mask;    c->low += c->low;     if(!(c->low & CABAC_MASK))        refill(c);     range= c->range<<(CABAC_BITS+1);    c->low -= range;    mask= c->low >> 31;    range &= mask;    c->low += range;    return (val^mask)-mask;}#endif /** * @return the number of bytes read or 0 if no end */#ifndef get_cabac_terminatestatic int av_unused get_cabac_terminate(CABACContext *c){    c->range -= 2;    if(c->low < c->range<<(CABAC_BITS+1)){        renorm_cabac_decoder_once(c);        return 0;    }else{        return c->bytestream - c->bytestream_start;    }}#endif /** * Skip @p n bytes and reset the decoder. * @return the address of the first skipped byte or NULL if there's less than @p n bytes left */#ifndef skip_bytesstatic av_unused const uint8_t* skip_bytes(CABACContext *c, int n) {    const uint8_t *ptr = c->bytestream;     if (c->low & 0x1)        ptr--;#if CABAC_BITS == 16    if (c->low & 0x1FF)        ptr--;#endif    if ((int) (c->bytestream_end - ptr) < n)        return NULL;    if (ff_init_cabac_decoder(c, ptr + n, c->bytestream_end - ptr - n) < 0)        return NULL;     return ptr;}#endif #endif /* AVCODEC_CABAC_FUNCTIONS_H */