textsubtitleparser.h

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// -*- Mode: c++ -*-
#ifndef TEXT_SUBTITLE_PARSER_H
#define TEXT_SUBTITLE_PARSER_H
 
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
}
 
// C++ headers
#include <cstdint>
#include <vector>
 
// Qt headers
#include <QObject>
#include <QMutexLocker>
#include <QStringList>
#include <QDateTime>
 
class text_subtitle_t
{
  public:
    text_subtitle_t(long start_, long end_) : m_start(start_), m_end(end_) {}
    text_subtitle_t() = default;
    text_subtitle_t(const text_subtitle_t&) = default;
    text_subtitle_t& operator= (const text_subtitle_t&) = default;
 
  public:
    uint64_t    m_start {0};  
    uint64_t    m_end   {0};  
    QStringList m_textLines;
};
 
using TextSubtitleList = std::vector<text_subtitle_t>;
 
class TextSubtitles : public QObject
{
    Q_OBJECT
 
  signals:
    void TextSubtitlesUpdated();
 
  public:
    ~TextSubtitles() override;
 
    void SetFilename(const QString &fileName) {
        QMutexLocker locker(&m_lock);
        m_fileName = fileName;
    }
 
    void SetLastLoaded(void);
    void SetByteCount(off_t count) {
        QMutexLocker locker(&m_lock);
        m_byteCount = count;
    }
    off_t GetByteCount(void) const { return m_byteCount; }
    void SetInProgress(bool isInProgress) {
        QMutexLocker locker(&m_lock);
        m_isInProgress = isInProgress;
    }
    void SetHasSubtitles(bool hasSubs) { m_hasSubtitles = hasSubs; }
    bool GetHasSubtitles() const { return m_hasSubtitles; }
 
    void Lock(void)   { m_lock.lock();   }
    void Unlock(void) { m_lock.unlock(); }
 
  private:
    QString                   m_fileName;
    QDateTime                 m_lastLoaded;
    off_t                     m_byteCount        {0};
    // Note: m_isInProgress is overly conservative because it doesn't
    // change from true to false after a recording completes.
    bool                      m_isInProgress     {false};
    bool                      m_hasSubtitles     {false};
#if QT_VERSION < QT_VERSION_CHECK(5,14,0)
    QMutex                    m_lock             {QMutex::Recursive};
#else
    QRecursiveMutex           m_lock;
#endif
};
 
class SubtitleReader;
class SubtitleLoadHelper;
 
class TextSubtitleParser
{
  public:
    TextSubtitleParser(SubtitleReader *parent, QString fileName, TextSubtitles *target);
    ~TextSubtitleParser();
    void LoadSubtitles(bool inBackground);
    int  decode(AVPacket *pkt);
    QByteArray GetSubHeader();
    void SeekFrame(int64_t ts, int flags);
    int ReadNextSubtitle(void);
 
  private:
    static int     read_packet(void *opaque, uint8_t *buf, int buf_size);
    static int64_t seek_packet(void *opaque, int64_t offset, int whence);
 
    SubtitleReader     *m_parent     {nullptr};
    SubtitleLoadHelper *m_loadHelper {nullptr};
    TextSubtitles      *m_target     {nullptr};
    QString             m_fileName;
 
    AVFormatContext    *m_fmtCtx     {nullptr};
    AVCodecContext     *m_decCtx     {nullptr};
    AVStream           *m_stream     {nullptr};
    AVPacket           *m_pkt        {nullptr};
};
 
#endif