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https://git.videolan.org/git/ffmpeg.git
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213 lines
6.3 KiB
C
213 lines
6.3 KiB
C
/*
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* DCA parser
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* Copyright (C) 2004 Gildas Bazin
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* Copyright (C) 2004 Benjamin Zores
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* Copyright (C) 2006 Benjamin Larsson
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* Copyright (C) 2007 Konstantin Shishkov
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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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#include "parser.h"
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#include "dca.h"
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#include "dcadata.h"
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#include "dca_parser.h"
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#include "get_bits.h"
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#include "put_bits.h"
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typedef struct DCAParseContext {
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ParseContext pc;
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uint32_t lastmarker;
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int size;
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int framesize;
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int hd_pos;
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} DCAParseContext;
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#define IS_MARKER(state, i, buf, buf_size) \
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((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
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|| (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \
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|| state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE)
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/**
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* Find the end of the current frame in the bitstream.
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* @return the position of the first byte of the next frame, or -1
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*/
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static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
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int buf_size)
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{
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int start_found, i;
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uint32_t state;
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ParseContext *pc = &pc1->pc;
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start_found = pc->frame_start_found;
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state = pc->state;
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i = 0;
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if (!start_found) {
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for (i = 0; i < buf_size; i++) {
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state = (state << 8) | buf[i];
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if (IS_MARKER(state, i, buf, buf_size)) {
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if (pc1->lastmarker && state == pc1->lastmarker) {
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start_found = 1;
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break;
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} else if (!pc1->lastmarker) {
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start_found = 1;
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pc1->lastmarker = state;
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break;
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}
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}
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}
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}
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if (start_found) {
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for (; i < buf_size; i++) {
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pc1->size++;
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state = (state << 8) | buf[i];
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if (state == DCA_HD_MARKER && !pc1->hd_pos)
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pc1->hd_pos = pc1->size;
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if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {
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if(pc1->framesize > pc1->size)
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continue;
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if(!pc1->framesize){
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pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
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}
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pc->frame_start_found = 0;
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pc->state = -1;
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pc1->size = 0;
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return i - 3;
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}
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}
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}
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pc->frame_start_found = start_found;
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pc->state = state;
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return END_NOT_FOUND;
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}
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static av_cold int dca_parse_init(AVCodecParserContext * s)
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{
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DCAParseContext *pc1 = s->priv_data;
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pc1->lastmarker = 0;
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return 0;
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}
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int ff_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
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int max_size)
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{
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uint32_t mrk;
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int i, tmp;
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const uint16_t *ssrc = (const uint16_t *) src;
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uint16_t *sdst = (uint16_t *) dst;
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PutBitContext pb;
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if ((unsigned) src_size > (unsigned) max_size)
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src_size = max_size;
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mrk = AV_RB32(src);
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switch (mrk) {
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case DCA_MARKER_RAW_BE:
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memcpy(dst, src, src_size);
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return src_size;
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case DCA_MARKER_RAW_LE:
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for (i = 0; i < (src_size + 1) >> 1; i++)
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*sdst++ = av_bswap16(*ssrc++);
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return src_size;
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case DCA_MARKER_14B_BE:
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case DCA_MARKER_14B_LE:
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init_put_bits(&pb, dst, max_size);
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for (i = 0; i < (src_size + 1) >> 1; i++, src += 2) {
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tmp = ((mrk == DCA_MARKER_14B_BE) ? AV_RB16(src) : AV_RL16(src)) & 0x3FFF;
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put_bits(&pb, 14, tmp);
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}
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flush_put_bits(&pb);
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return (put_bits_count(&pb) + 7) >> 3;
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default:
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return AVERROR_INVALIDDATA;
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}
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}
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static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration,
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int *sample_rate)
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{
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GetBitContext gb;
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uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };
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int ret, sample_blocks, sr_code;
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if (buf_size < 12)
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return AVERROR_INVALIDDATA;
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if ((ret = ff_dca_convert_bitstream(buf, 12, hdr, 12)) < 0)
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return ret;
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init_get_bits(&gb, hdr, 96);
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skip_bits_long(&gb, 39);
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sample_blocks = get_bits(&gb, 7) + 1;
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if (sample_blocks < 8)
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return AVERROR_INVALIDDATA;
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*duration = 256 * (sample_blocks / 8);
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skip_bits(&gb, 20);
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sr_code = get_bits(&gb, 4);
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*sample_rate = dca_sample_rates[sr_code];
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if (*sample_rate == 0)
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return AVERROR_INVALIDDATA;
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return 0;
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}
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static int dca_parse(AVCodecParserContext * s,
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AVCodecContext * avctx,
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const uint8_t ** poutbuf, int *poutbuf_size,
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const uint8_t * buf, int buf_size)
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{
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DCAParseContext *pc1 = s->priv_data;
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ParseContext *pc = &pc1->pc;
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int next, duration, sample_rate;
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if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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} else {
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next = dca_find_frame_end(pc1, buf, buf_size);
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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}
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/* read the duration and sample rate from the frame header */
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if (!dca_parse_params(buf, buf_size, &duration, &sample_rate)) {
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s->duration = duration;
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if (!avctx->sample_rate)
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avctx->sample_rate = sample_rate;
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} else
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s->duration = 0;
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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AVCodecParser ff_dca_parser = {
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.codec_ids = { CODEC_ID_DTS },
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.priv_data_size = sizeof(DCAParseContext),
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.parser_init = dca_parse_init,
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.parser_parse = dca_parse,
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.parser_close = ff_parse_close,
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};
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