1 files changed, 212 insertions, 0 deletions
diff --git a/libavformat/subtitles.h b/libavformat/subtitles.h
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+/*
+ * 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
+    int keep_duplicates;    ///< set to 1 to keep duplicated subtitle events
+} 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, sort subtitles by PTS (and then byte position), and
+ * drop duplicated events.
+ */
+void ff_subtitles_queue_finalize(void *log_ctx, 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 */