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1c35333671
If ff_subtitles_queue_insert() were given a NULL buffer with 0 length, it would still attempt to grow the packet or memcpy depending on if merge option is enabled. In this commit, allow passing a NULL buffer with 0 length without attempting to do such operations. This way, if a subtitle demuxer happens to pass an empty cue or wants to use av_get_packet() to read bytes, there are no unnecessary operations on the packet after it is allocated. Signed-off-by: Marth64 <marth64@proxyid.net>
231 lines
7.6 KiB
C
231 lines
7.6 KiB
C
/*
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* Copyright (c) 2012 Clément Bœsch
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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#ifndef AVFORMAT_SUBTITLES_H
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#define AVFORMAT_SUBTITLES_H
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#include <stdint.h>
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#include <stddef.h>
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#include "avformat.h"
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#include "libavutil/bprint.h"
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#include "avio_internal.h"
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enum sub_sort {
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SUB_SORT_TS_POS = 0, ///< sort by timestamps, then position
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SUB_SORT_POS_TS, ///< sort by position, then timestamps
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};
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enum ff_utf_type {
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FF_UTF_8, // or other 8 bit encodings
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FF_UTF16LE,
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FF_UTF16BE,
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};
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typedef struct {
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int type;
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AVIOContext *pb;
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unsigned char buf[8];
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int buf_pos, buf_len;
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FFIOContext buf_pb;
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} FFTextReader;
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/**
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* Initialize the FFTextReader from the given AVIOContext. This function will
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* read some bytes from pb, and test for UTF-8 or UTF-16 BOMs. Further accesses
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* to FFTextReader will read more data from pb.
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* If s is not NULL, the user will be warned if a UTF-16 conversion takes place.
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*
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* The purpose of FFTextReader is to transparently convert read data to UTF-8
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* if the stream had a UTF-16 BOM.
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*
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* @param s Pointer to provide av_log context
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* @param r object which will be initialized
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* @param pb stream to read from (referenced as long as FFTextReader is in use)
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*/
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void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb);
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/**
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* Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
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*
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* @param r object which will be initialized
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* @param buf buffer to read from (referenced as long as FFTextReader is in use)
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* @param size size of buf
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*/
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void ff_text_init_buf(FFTextReader *r, const void *buf, size_t size);
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/**
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* Return the byte position of the next byte returned by ff_text_r8(). For
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* UTF-16 source streams, this will return the original position, but it will
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* be incorrect if a codepoint was only partially read with ff_text_r8().
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*/
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int64_t ff_text_pos(FFTextReader *r);
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/**
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* Return the next byte. The return value is always 0 - 255. Returns 0 on EOF.
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* If the source stream is UTF-16, this reads from the stream converted to
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* UTF-8. On invalid UTF-16, 0 is returned.
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*/
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int ff_text_r8(FFTextReader *r);
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/**
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* Return non-zero if EOF was reached.
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*/
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int ff_text_eof(FFTextReader *r);
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/**
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* Like ff_text_r8(), but don't remove the byte from the buffer.
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*/
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int ff_text_peek_r8(FFTextReader *r);
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/**
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* Read the given number of bytes (in UTF-8). On error or EOF, \0 bytes are
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* written.
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*/
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void ff_text_read(FFTextReader *r, char *buf, size_t size);
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typedef struct {
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AVPacket **subs; ///< array of subtitles packets
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int nb_subs; ///< number of subtitles packets
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int allocated_size; ///< allocated size for subs
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int current_sub_idx; ///< current position for the read packet callback
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enum sub_sort sort; ///< sort method to use when finalizing subtitles
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int keep_duplicates; ///< set to 1 to keep duplicated subtitle events
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} FFDemuxSubtitlesQueue;
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/**
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* Insert a new subtitle event.
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*
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* @param event the subtitle line (not zero terminated) or NULL on not yet available event
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* @param len the length of the event (in strlen() sense, so without '\0')
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* @param merge set to 1 if the current event should be concatenated with the
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* previous one instead of adding a new entry, 0 otherwise
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*/
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AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
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const uint8_t *event, size_t len, int merge);
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/**
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* Same as ff_subtitles_queue_insert but takes an AVBPrint input.
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* Avoids common errors like handling incomplete AVBPrint.
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*/
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AVPacket *ff_subtitles_queue_insert_bprint(FFDemuxSubtitlesQueue *q,
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const AVBPrint *event, int merge);
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/**
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* Set missing durations, sort subtitles by PTS (and then byte position), and
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* drop duplicated events.
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*/
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void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q);
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/**
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* Generic read_packet() callback for subtitles demuxers using this queue
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* system.
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*/
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int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt);
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/**
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* Update current_sub_idx to emulate a seek. Except the first parameter, it
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* matches FFInputFormat->read_seek2 prototypes.
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*/
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int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
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int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
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/**
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* Remove and destroy all the subtitles packets.
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*/
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void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q);
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int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt);
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int ff_subtitles_read_seek(AVFormatContext *s, int stream_index,
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int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
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int ff_subtitles_read_close(AVFormatContext *s);
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/**
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* SMIL helper to load next chunk ("<...>" or untagged content) in buf.
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*
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* @param c cached character, to avoid a backward seek
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* @return size of chunk or error, e.g. AVERROR(ENOMEM) on incomplete buf
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*/
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int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c);
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/**
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* SMIL helper to point on the value of an attribute in the given tag.
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*
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* @param s SMIL tag ("<...>")
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* @param attr the attribute to look for
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*/
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const char *ff_smil_get_attr_ptr(const char *s, const char *attr);
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/**
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* @brief Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
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*/
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av_warn_unused_result
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int ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
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/**
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* @brief Read a subtitles chunk from FFTextReader.
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*
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* A chunk is defined by a multiline "event", ending with a second line break.
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* The trailing line breaks are trimmed. CRLF are supported.
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* Example: "foo\r\nbar\r\n\r\nnext" will print "foo\r\nbar" into buf, and pb
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* will focus on the 'n' of the "next" string.
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*
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* @param tr I/O context
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* @param buf an initialized buf where the chunk is written
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* @return 0 on success, error value otherwise, e.g. AVERROR(ENOMEM) if buf is incomplete
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*
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* @note buf is cleared before writing into it.
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*/
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av_warn_unused_result
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int ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf);
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/**
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* Get the number of characters to increment to jump to the next line, or to
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* the end of the string.
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* The function handles the following line breaks schemes:
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* LF, CRLF (MS), or standalone CR (old MacOS).
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*/
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static av_always_inline int ff_subtitles_next_line(const char *ptr)
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{
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int n = strcspn(ptr, "\r\n");
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ptr += n;
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while (*ptr == '\r') {
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ptr++;
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n++;
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}
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if (*ptr == '\n')
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n++;
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return n;
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}
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/**
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* Read a line of text. Discards line ending characters.
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* The function handles the following line breaks schemes:
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* LF, CRLF (MS), or standalone CR (old MacOS).
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*
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* Returns the number of bytes written to buf. Always writes a terminating 0,
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* similar as with snprintf.
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*
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* @note returns a negative error code if a \0 byte is found
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*/
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ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size);
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#endif /* AVFORMAT_SUBTITLES_H */
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