Aegisub/aegisub/src/mkv_wrap.cpp

// Copyright (c) 2004-2006, Rodrigo Braz Monteiro, Mike Matsnev
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
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// Aegisub Project http://www.aegisub.org/

/// @file mkv_wrap.cpp
/// @brief High-level interface for obtaining various data from Matroska files
/// @ingroup video_input
///

#include "config.h"

#ifndef AGI_PRE
#include <errno.h>
#include <cstdint>
#include <stdio.h>

#include <algorithm>
#include <iterator>

#include <wx/filename.h>
#include <wx/tokenzr.h>
#include <wx/choicdlg.h> // Keep this last so wxUSE_CHOICEDLG is set.
#endif

#include "mkv_wrap.h"

#include "ass_file.h"
#include "ass_parser.h"
#include "ass_time.h"
#include "compat.h"
#include "dialog_progress.h"
#include "MatroskaParser.h"

class MkvStdIO : public InputStream {
public:
	MkvStdIO(wxString filename);
	~MkvStdIO() { if (fp) fclose(fp); }

	FILE *fp;
	int error;
};

#define CACHESIZE     1024

#ifdef __VISUALC__
#define std_fseek _fseeki64
#define std_ftell _ftelli64
#else
#define std_fseek fseeko
#define std_ftell ftello
#endif

static void read_subtitles(agi::ProgressSink *ps, MatroskaFile *file, MkvStdIO *input, bool srt, double totalTime, AssParser *parser) {
	std::map<int, wxString> subList;
	char *readBuf = 0;
	size_t readBufSize = 0;

	// Load blocks
	ulonglong startTime, endTime, filePos;
	unsigned int rt, frameSize, frameFlags;

	while (mkv_ReadFrame(file,0,&rt,&startTime,&endTime,&filePos,&frameSize,&frameFlags) == 0) {
		if (ps->IsCancelled()) {
			delete[] readBuf;
			return;
		}

		// Read to temp
		if (frameSize > readBufSize) {
			delete[] readBuf;
			readBufSize = frameSize * 2;
			readBuf = new char[readBufSize];
		}
		else if (frameSize == 0)
			continue;

		std_fseek(input->fp, filePos, SEEK_SET);
		fread(readBuf, 1, frameSize, input->fp);
		wxString blockString(readBuf, wxConvUTF8, frameSize);

		// Get start and end times
		longlong timecodeScaleLow = 1000000;
		AssTime subStart = startTime / timecodeScaleLow;
		AssTime subEnd = endTime / timecodeScaleLow;

		// Process SSA/ASS
		if (!srt) {
			long order = 0, layer = 0;
			wxString afterOrder, afterLayer;
			blockString.BeforeFirst(',', &afterOrder).ToLong(&order);
			afterOrder.BeforeFirst(',', &afterLayer).ToLong(&layer);

			subList[order] = wxString::Format("Dialogue: %d,%s,%s,%s", (int)layer, subStart.GetAssFormated(), subEnd.GetAssFormated(), afterLayer);
		}
		// Process SRT
		else {
			blockString = wxString::Format("Dialogue: 0,%s,%s,Default,,0,0,0,,%s", subStart.GetAssFormated(), subEnd.GetAssFormated(), blockString);
			blockString.Replace("\r\n","\\N");
			blockString.Replace("\r","\\N");
			blockString.Replace("\n","\\N");

			subList[subList.size()] = blockString;
		}

		ps->SetProgress(startTime / timecodeScaleLow, totalTime);
	}

	delete[] readBuf;

	// Insert into file
	for (auto order_value_pair : subList) {
		parser->AddLine(order_value_pair.second);
	}
}

void MatroskaWrapper::GetSubtitles(wxString const& filename, AssFile *target) {
	MkvStdIO input(filename);
	char err[2048];
	MatroskaFile *file = mkv_Open(&input, err, sizeof(err));
	if (!file) throw MatroskaException(err);

	try {
		// Get info
		unsigned tracks = mkv_GetNumTracks(file);
		TrackInfo *trackInfo;
		std::vector<unsigned> tracksFound;
		wxArrayString tracksNames;
		unsigned trackToRead;

		// Find tracks
		for (unsigned track = 0; track < tracks; track++) {
			trackInfo = mkv_GetTrackInfo(file,track);

			// Subtitle track
			if (trackInfo->Type == 0x11) {
				wxString CodecID = wxString(trackInfo->CodecID,*wxConvCurrent);
				wxString TrackName = wxString(trackInfo->Name,*wxConvCurrent);
				wxString TrackLanguage = wxString(trackInfo->Language,*wxConvCurrent);

				// Known subtitle format
				if (CodecID == "S_TEXT/SSA" || CodecID == "S_TEXT/ASS" || CodecID == "S_TEXT/UTF8") {
					tracksFound.push_back(track);
					tracksNames.Add(wxString::Format("%d (%s %s): %s", track, CodecID, TrackLanguage, TrackName));
				}
			}
		}

		// No tracks found
		if (tracksFound.empty())
			throw MatroskaException("File has no recognised subtitle tracks.");

		// Only one track found
		if (tracksFound.size() == 1) {
			trackToRead = tracksFound[0];
		}
		// Pick a track
		else {
			int choice = wxGetSingleChoiceIndex(_("Choose which track to read:"), _("Multiple subtitle tracks found"), tracksNames);
			if (choice == -1)
				throw agi::UserCancelException("cancelled");

			trackToRead = tracksFound[choice];
		}

		// Picked track
		mkv_SetTrackMask(file, ~(1 << trackToRead));
		trackInfo = mkv_GetTrackInfo(file,trackToRead);
		wxString CodecID = wxString(trackInfo->CodecID,*wxConvCurrent);
		bool srt = CodecID == "S_TEXT/UTF8";
		bool ssa = CodecID == "S_TEXT/SSA";

		AssParser parser(target, !ssa);

		// Read private data if it's ASS/SSA
		if (!srt) {
			// Read raw data
			trackInfo = mkv_GetTrackInfo(file,trackToRead);
			wxString privString((const char *)trackInfo->CodecPrivate, wxConvUTF8, trackInfo->CodecPrivateSize);

			// Load into file
			wxStringTokenizer token(privString, "\r\n", wxTOKEN_STRTOK);
			while (token.HasMoreTokens())
				parser.AddLine(token.GetNextToken());
		}
		// Load default if it's SRT
		else {
			target->LoadDefault(false);
			parser.AddLine("[Events]");
		}

		// Read timecode scale
		SegmentInfo *segInfo = mkv_GetFileInfo(file);
		longlong timecodeScale = mkv_TruncFloat(trackInfo->TimecodeScale) * segInfo->TimecodeScale;

		// Progress bar
		double totalTime = double(segInfo->Duration) / timecodeScale;
		DialogProgress progress(nullptr, _("Parsing Matroska"), _("Reading subtitles from Matroska file."));
		progress.Run([&](agi::ProgressSink *ps) { read_subtitles(ps, file, &input, srt, totalTime, &parser); });
	}
	catch (...) {
		mkv_Close(file);
		throw;
	}
}

bool MatroskaWrapper::HasSubtitles(wxString const& filename) {
	char err[2048];
	try {
		MkvStdIO input(filename);
		MatroskaFile* file = mkv_Open(&input, err, sizeof(err));
		if (!file) return false;

		// Find tracks
		int tracks = mkv_GetNumTracks(file);
		for (int track = 0; track < tracks; track++) {
			TrackInfo *trackInfo = mkv_GetTrackInfo(file, track);

			if (trackInfo->Type == 0x11) {
				wxString CodecID = wxString(trackInfo->CodecID, *wxConvCurrent);
				if (CodecID == "S_TEXT/SSA" || CodecID == "S_TEXT/ASS" || CodecID == "S_TEXT/UTF8") {
					mkv_Close(file);
					return true;
				}
			}
		}

		mkv_Close(file);
		return false;
	}
	catch (...) {
		// We don't care about why we couldn't read subtitles here
		return false;
	}
}

int StdIoRead(InputStream *_st, ulonglong pos, void *buffer, int count) {
  MkvStdIO *st = (MkvStdIO *) _st;
  size_t  rd;
  if (std_fseek(st->fp, pos, SEEK_SET)) {
    st->error = errno;
    return -1;
  }
  rd = fread(buffer, 1, count, st->fp);
  if (rd == 0) {
    if (feof(st->fp))
      return 0;
    st->error = errno;
    return -1;
  }
  return rd;
}

/// @brief scan for a signature sig(big-endian) starting at file position pos
/// @return position of the first byte of signature or -1 if error/not found
longlong StdIoScan(InputStream *_st, ulonglong start, unsigned signature) {
  MkvStdIO *st = (MkvStdIO *) _st;
  int	      c;
  unsigned    cmp = 0;
  FILE	      *fp = st->fp;

  if (std_fseek(fp, start, SEEK_SET))
    return -1;

  while ((c = getc(fp)) != EOF) {
    cmp = ((cmp << 8) | c) & 0xffffffff;
    if (cmp == signature)
      return std_ftell(fp) - 4;
  }

  return -1;
}

/// @brief This is used to limit readahead.
unsigned StdIoGetCacheSize(InputStream *st) {
  return CACHESIZE;
}

/// @brief Get last error message
const char *StdIoGetLastError(InputStream *st) {
  return strerror(((MkvStdIO *)st)->error);
}

/// @brief Memory allocation, this is done via stdlib
void *StdIoMalloc(InputStream *, size_t size) {
  return malloc(size);
}

void *StdIoRealloc(InputStream *, void *mem, size_t size) {
  return realloc(mem, size);
}

void StdIoFree(InputStream *, void *mem) {
  free(mem);
}

int StdIoProgress(InputStream *, ulonglong cur, ulonglong max) {
  return 1;
}

longlong StdIoGetFileSize(InputStream *_st) {
	MkvStdIO *st = (MkvStdIO *) _st;
	longlong epos = 0;
	longlong cpos = std_ftell(st->fp);
	std_fseek(st->fp, 0, SEEK_END);
	epos = std_ftell(st->fp);
	std_fseek(st->fp, cpos, SEEK_SET);
	return epos;
}

MkvStdIO::MkvStdIO(wxString filename)
: error(0)
{
	read = StdIoRead;
	scan = StdIoScan;
	getcachesize = StdIoGetCacheSize;
	geterror = StdIoGetLastError;
	memalloc = StdIoMalloc;
	memrealloc = StdIoRealloc;
	memfree = StdIoFree;
	progress = StdIoProgress;
	getfilesize = StdIoGetFileSize;

	wxFileName fname(filename);
#ifdef __VISUALC__
	fp = _wfopen(fname.GetFullPath().wc_str(), L"rb");
#else
	fp = fopen(fname.GetFullPath().utf8_str(), "rb");
#endif
	if (fp) {
		setvbuf(fp, nullptr, _IOFBF, CACHESIZE);
	}
	else {
		throw agi::FileNotFoundError(STD_STR(filename));
	}
}