/*
  * Copyright (c) 2012 Clément Bœsch
  *
  * 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
  */
 
 #ifndef AVFORMAT_SUBTITLES_H
 #define AVFORMAT_SUBTITLES_H
 
 #include <stdint.h>

 #include <stddef.h>

 #include "avformat.h"

 #include "libavutil/bprint.h"

 enum sub_sort {
     SUB_SORT_TS_POS = 0,    ///< sort by timestamps, then position
     SUB_SORT_POS_TS,        ///< sort by position, then timestamps
 };
 

 enum ff_utf_type {
     FF_UTF_8,       // or other 8 bit encodings
     FF_UTF16LE,
     FF_UTF16BE,
 };
 
 typedef struct {
     int type;
     AVIOContext *pb;
     unsigned char buf[8];
     int buf_pos, buf_len;
     AVIOContext buf_pb;
 } FFTextReader;
 
 /**
  * Initialize the FFTextReader from the given AVIOContext. This function will
  * read some bytes from pb, and test for UTF-8 or UTF-16 BOMs. Further accesses
  * to FFTextReader will read more data from pb.

  * If s is not NULL, the user will be warned if a UTF-16 conversion takes place.

  *
  * The purpose of FFTextReader is to transparently convert read data to UTF-8
  * if the stream had a UTF-16 BOM.
  *

  * @param s Pointer to provide av_log context

  * @param r object which will be initialized
  * @param pb stream to read from (referenced as long as FFTextReader is in use)
  */

 void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb);

 
 /**
  * Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
  *
  * @param r object which will be initialized
  * @param buf buffer to read from (referenced as long as FFTextReader is in use)
  * @param size size of buf
  */
 void ff_text_init_buf(FFTextReader *r, void *buf, size_t size);
 
 /**
  * Return the byte position of the next byte returned by ff_text_r8(). For
  * UTF-16 source streams, this will return the original position, but it will
  * be incorrect if a codepoint was only partially read with ff_text_r8().
  */
 int64_t ff_text_pos(FFTextReader *r);
 
 /**
  * Return the next byte. The return value is always 0 - 255. Returns 0 on EOF.
  * If the source stream is UTF-16, this reads from the stream converted to
  * UTF-8. On invalid UTF-16, 0 is returned.
  */
 int ff_text_r8(FFTextReader *r);
 
 /**

  * Return non-zero if EOF was reached.
  */
 int ff_text_eof(FFTextReader *r);
 
 /**
  * Like ff_text_r8(), but don't remove the byte from the buffer.
  */
 int ff_text_peek_r8(FFTextReader *r);
 
 /**

  * Read the given number of bytes (in UTF-8). On error or EOF, \0 bytes are
  * written.
  */
 void ff_text_read(FFTextReader *r, char *buf, size_t size);
 

 typedef struct {
     AVPacket *subs;         ///< array of subtitles packets
     int nb_subs;            ///< number of subtitles packets
     int allocated_size;     ///< allocated size for subs
     int current_sub_idx;    ///< current position for the read packet callback

     enum sub_sort sort;     ///< sort method to use when finalizing subtitles

 } FFDemuxSubtitlesQueue;
 
 /**
  * Insert a new subtitle event.
  *
  * @param event the subtitle line, may not be zero terminated
  * @param len   the length of the event (in strlen() sense, so without '\0')
  * @param merge set to 1 if the current event should be concatenated with the
  *              previous one instead of adding a new entry, 0 otherwise
  */
 AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,

                                     const uint8_t *event, size_t len, int merge);

 
 /**
  * Set missing durations and sort subtitles by PTS, and then byte position.
  */
 void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q);
 
 /**
  * Generic read_packet() callback for subtitles demuxers using this queue
  * system.
  */
 int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt);
 
 /**

  * Update current_sub_idx to emulate a seek. Except the first parameter, it
  * matches AVInputFormat->read_seek2 prototypes.
  */
 int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
                             int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
 
 /**

  * Remove and destroy all the subtitles packets.
  */
 void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q);
 

 /**
  * SMIL helper to load next chunk ("<...>" or untagged content) in buf.
  *
  * @param c cached character, to avoid a backward seek
  */

 int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c);
 
 /**

  * SMIL helper to point on the value of an attribute in the given tag.
  *
  * @param s    SMIL tag ("<...>")
  * @param attr the attribute to look for
  */
 const char *ff_smil_get_attr_ptr(const char *s, const char *attr);
 

 /**

  * @brief Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
  */
 void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
 
 /**
  * @brief Read a subtitles chunk from FFTextReader.

  *
  * A chunk is defined by a multiline "event", ending with a second line break.

  * The trailing line breaks are trimmed. CRLF are supported.

  * Example: "foo\r\nbar\r\n\r\nnext" will print "foo\r\nbar" into buf, and pb
  * will focus on the 'n' of the "next" string.
  *

  * @param tr  I/O context

  * @param buf an initialized buf where the chunk is written
  *
  * @note buf is cleared before writing into it.
  */

 void ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf);

 /**
  * Get the number of characters to increment to jump to the next line, or to
  * the end of the string.

  * The function handles the following line breaks schemes:
  * LF, CRLF (MS), or standalone CR (old MacOS).

  */
 static av_always_inline int ff_subtitles_next_line(const char *ptr)
 {

     int n = strcspn(ptr, "\r\n");
     ptr += n;
     if (*ptr == '\r') {
         ptr++;
         n++;
     }
     if (*ptr == '\n')
         n++;
     return n;

 }
 

 /**
  * Read a line of text. Discards line ending characters.
  * The function handles the following line breaks schemes:
  * LF, CRLF (MS), or standalone CR (old MacOS).
  *
  * Returns the number of bytes written to buf. Always writes a terminating 0,
  * similar as with snprintf.
  *
  * @note returns a negative error code if a \0 byte is found
  */
 ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size);
 

 #endif /* AVFORMAT_SUBTITLES_H */