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1 d592f67f Michael Niedermayer
/*
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 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
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 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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 *
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 * This library 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 of the License, or (at your option) any later version.
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 *
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 * This library 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 this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 */
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/**
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 * @file cabac.c
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 * Context Adaptive Binary Arithmetic Coder.
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 */
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#include <string.h>
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#include "common.h"
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#include "cabac.h"
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const uint8_t ff_h264_lps_range[64][4]= {
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{128,176,208,240}, {128,167,197,227}, {128,158,187,216}, {123,150,178,205},
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{116,142,169,195}, {111,135,160,185}, {105,128,152,175}, {100,122,144,166},
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{ 95,116,137,158}, { 90,110,130,150}, { 85,104,123,142}, { 81, 99,117,135},
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{ 77, 94,111,128}, { 73, 89,105,122}, { 69, 85,100,116}, { 66, 80, 95,110},
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{ 62, 76, 90,104}, { 59, 72, 86, 99}, { 56, 69, 81, 94}, { 53, 65, 77, 89},
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{ 51, 62, 73, 85}, { 48, 59, 69, 80}, { 46, 56, 66, 76}, { 43, 53, 63, 72},
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{ 41, 50, 59, 69}, { 39, 48, 56, 65}, { 37, 45, 54, 62}, { 35, 43, 51, 59},
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{ 33, 41, 48, 56}, { 32, 39, 46, 53}, { 30, 37, 43, 50}, { 29, 35, 41, 48},
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{ 27, 33, 39, 45}, { 26, 31, 37, 43}, { 24, 30, 35, 41}, { 23, 28, 33, 39},
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{ 22, 27, 32, 37}, { 21, 26, 30, 35}, { 20, 24, 29, 33}, { 19, 23, 27, 31},
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{ 18, 22, 26, 30}, { 17, 21, 25, 28}, { 16, 20, 23, 27}, { 15, 19, 22, 25},
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{ 14, 18, 21, 24}, { 14, 17, 20, 23}, { 13, 16, 19, 22}, { 12, 15, 18, 21},
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{ 12, 14, 17, 20}, { 11, 14, 16, 19}, { 11, 13, 15, 18}, { 10, 12, 15, 17},
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{ 10, 12, 14, 16}, {  9, 11, 13, 15}, {  9, 11, 12, 14}, {  8, 10, 12, 14},
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{  8,  9, 11, 13}, {  7,  9, 11, 12}, {  7,  9, 10, 12}, {  7,  8, 10, 11},
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{  6,  8,  9, 11}, {  6,  7,  9, 10}, {  6,  7,  8,  9}, {  2,  2,  2,  2},
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};
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const uint8_t ff_h264_mps_state[64]= {
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  1, 2, 3, 4, 5, 6, 7, 8,
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  9,10,11,12,13,14,15,16,
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 17,18,19,20,21,22,23,24,
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 25,26,27,28,29,30,31,32,
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 33,34,35,36,37,38,39,40,
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 41,42,43,44,45,46,47,48,
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 49,50,51,52,53,54,55,56,
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 57,58,59,60,61,62,62,63,
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};
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const uint8_t ff_h264_lps_state[64]= {
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  0, 0, 1, 2, 2, 4, 4, 5,
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  6, 7, 8, 9, 9,11,11,12,
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 13,13,15,15,16,16,18,18,
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 19,19,21,21,22,22,23,24,
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 24,25,26,26,27,27,28,29,
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 29,30,30,30,31,32,32,33,
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 33,33,34,34,35,35,35,36,
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 36,36,37,37,37,38,38,63,
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};
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/**
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 *
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 * @param buf_size size of buf in bits
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 */
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void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
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    init_put_bits(&c->pb, buf, buf_size, NULL, NULL);
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    c->low= 0;
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    c->range= 0x1FE;
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    c->outstanding_count= 0;
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#ifdef STRICT_LIMITS
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    c->sym_count =0;
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#endif
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    c->pb.bit_left++; //avoids firstBitFlag
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}
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/**
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 *
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 * @param buf_size size of buf in bits
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 */
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void ff_init_cabac_decoder(CABACContext *c, uint8_t *buf, int buf_size){
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    c->bytestream_start= 
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    c->bytestream= buf;
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    c->low= *c->bytestream++;
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    c->low= (c->low<<9) + ((*c->bytestream++)<<1);
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    c->range= 0x1FE00;
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    c->bits_left= 7;
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}
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void ff_init_cabac_states(CABACContext *c, uint8_t const (*lps_range)[4], 
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                          uint8_t const *mps_state, uint8_t const *lps_state, int state_count){
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    int i, j;
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    for(i=0; i<state_count; i++){
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        for(j=0; j<4; j++){ //FIXME check if this is worth the 1 shift we save
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            c->lps_range[2*i+0][j]=
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            c->lps_range[2*i+1][j]= lps_range[i][j];
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        }
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        c->mps_state[2*i+0]= 2*mps_state[i];
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        c->mps_state[2*i+1]= 2*mps_state[i]+1;
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        if(lps_state[i]){
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            c->lps_state[2*i+0]= 2*lps_state[i];
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            c->lps_state[2*i+1]= 2*lps_state[i]+1;
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        }else{
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            c->lps_state[2*i+0]= 1;
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            c->lps_state[2*i+1]= 0;
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        }
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    }
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}
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#if 0 //selftest
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#define SIZE 10240
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int main(){
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    CABACContext c;
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    uint8_t b[9*SIZE];
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    uint8_t r[9*SIZE];
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    int i;
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    uint8_t state[10]= {0};
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    ff_init_cabac_encoder(&c, b, SIZE);
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    ff_init_cabac_states(&c, ff_h264_lps_range, ff_h264_mps_state, ff_h264_lps_state, 64);
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    for(i=0; i<SIZE; i++){
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        r[i]= random()%7;
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    }
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        put_cabac_bypass(&c, r[i]&1);
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STOP_TIMER("put_cabac_bypass")
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    }
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        put_cabac(&c, state, r[i]&1);
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STOP_TIMER("put_cabac")
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    }
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        put_cabac_u(&c, state, r[i], 6, 3, i&1);
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STOP_TIMER("put_cabac_u")
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    }    
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        put_cabac_ueg(&c, state, r[i], 3, 0, 1, 2);
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STOP_TIMER("put_cabac_ueg")
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    }    
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    put_cabac_terminate(&c, 1);
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    ff_init_cabac_decoder(&c, b, SIZE);
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    memset(state, 0, sizeof(state));
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        if( (r[i]&1) != get_cabac_bypass(&c) )
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            printf("CABAC bypass failure at %d\n", i);
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STOP_TIMER("get_cabac_bypass")
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    }
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        if( (r[i]&1) != get_cabac(&c, state) )
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            printf("CABAC failure at %d\n", i);
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STOP_TIMER("get_cabac")
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    }
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        if( r[i] != get_cabac_u(&c, state, (i&1) ? 6 : 7, 3, i&1) )
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            printf("CABAC unary (truncated) binarization failure at %d\n", i);
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STOP_TIMER("get_cabac_u")
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    }
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    for(i=0; i<SIZE; i++){
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START_TIMER
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        if( r[i] != get_cabac_ueg(&c, state, 3, 0, 1, 2))
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            printf("CABAC unary (truncated) binarization failure at %d\n", i);
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STOP_TIMER("get_cabac_ueg")
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    }
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    if(!get_cabac_terminate(&c))
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        printf("where's the Terminator?\n");
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    return 0;
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}
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#endif