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:
//
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//     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
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//   * 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 "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"

#include <libaegisub/file_mapping.h>
#include <libaegisub/format.h>
#include <libaegisub/scoped_ptr.h>

#include <algorithm>
#include <boost/algorithm/string/replace.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/range/irange.hpp>
#include <boost/tokenizer.hpp>
#include <iterator>

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

struct MkvStdIO final : InputStream {
	agi::read_file_mapping file;
	std::string error;

	static int Read(InputStream *st, uint64_t pos, void *buffer, int count) {
		auto *self = static_cast<MkvStdIO*>(st);
		if (pos >= self->file.size())
			return 0;

		auto remaining = self->file.size() - pos;
		if (remaining < INT_MAX)
			count = std::min(static_cast<int>(remaining), count);

		try {
			memcpy(buffer, self->file.read(pos, count), count);
		}
		catch (agi::Exception const& e) {
			self->error = e.GetChainedMessage();
			return -1;
		}

		return count;
	}

	static int64_t Scan(InputStream *st, uint64_t start, unsigned signature) {
		auto *self = static_cast<MkvStdIO*>(st);
		try {
			unsigned cmp = 0;
			for (auto i : boost::irange(start, self->file.size())) {
				int c = *self->file.read(i, 1);
				cmp = ((cmp << 8) | c) & 0xffffffff;
				if (cmp == signature)
					return i - 4;
			}
		}
		catch (agi::Exception const& e) {
			self->error = e.GetChainedMessage();
		}

		return -1;
	}

	static int64_t Size(InputStream *st) {
		return static_cast<MkvStdIO*>(st)->file.size();
	}

	MkvStdIO(agi::fs::path const& filename) : file(filename) {
		read = &MkvStdIO::Read;
		scan = &MkvStdIO::Scan;
		getcachesize = [](InputStream *) -> unsigned int { return 16 * 1024 * 1024; };
		geterror = [](InputStream *st) -> const char * { return ((MkvStdIO *)st)->error.c_str(); };
		memalloc = [](InputStream *, size_t size) { return malloc(size); };
		memrealloc = [](InputStream *, void *mem, size_t size) { return realloc(mem, size); };
		memfree = [](InputStream *, void *mem) { free(mem); };
		progress = [](InputStream *, uint64_t, uint64_t) { return 1; };
		getfilesize = &MkvStdIO::Size;
	}
};

static void read_subtitles(agi::ProgressSink *ps, MatroskaFile *file, MkvStdIO *input, bool srt, double totalTime, AssParser *parser) {
	std::vector<std::pair<int, std::string>> subList;

	// Load blocks
	uint64_t startTime, endTime, filePos;
	unsigned int rt, frameSize, frameFlags;

	while (mkv_ReadFrame(file, 0, &rt, &startTime, &endTime, &filePos, &frameSize, &frameFlags) == 0) {
		if (ps->IsCancelled()) return;
		if (frameSize == 0) continue;

		const auto readBuf = input->file.read(filePos, frameSize);
		const auto readBufEnd = readBuf + frameSize;

		// Get start and end times
		int64_t timecodeScaleLow = 1000000;
		AssTime subStart = startTime / timecodeScaleLow;
		AssTime subEnd = endTime / timecodeScaleLow;

		using str_range = boost::iterator_range<const char *>;

		// Process SSA/ASS
		if (!srt) {
			auto first = std::find(readBuf, readBufEnd, ',');
			if (first == readBufEnd) continue;
			auto second = std::find(first + 1, readBufEnd, ',');
			if (second == readBufEnd) continue;

			subList.emplace_back(
				boost::lexical_cast<int>(str_range(readBuf, first)),
				agi::format("Dialogue: %d,%s,%s,%s"
					, boost::lexical_cast<int>(str_range(first + 1, second))
					, subStart.GetAssFormated()
					, subEnd.GetAssFormated()
					, str_range(second + 1, readBufEnd)));
		}
		// Process SRT
		else {
			auto line = agi::format("Dialogue: 0,%s,%s,Default,,0,0,0,,%s"
				, subStart.GetAssFormated()
				, subEnd.GetAssFormated()
				, str_range(readBuf, readBufEnd));
			boost::replace_all(line, "\r\n", "\\N");
			boost::replace_all(line, "\r", "\\N");
			boost::replace_all(line, "\n", "\\N");

			subList.emplace_back(subList.size(), std::move(line));
		}

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

	// Insert into file
	sort(begin(subList), end(subList));
	for (auto order_value_pair : subList)
		parser->AddLine(order_value_pair.second);
}

void MatroskaWrapper::GetSubtitles(agi::fs::path const& filename, AssFile *target) {
	MkvStdIO input(filename);
	char err[2048];
	agi::scoped_holder<MatroskaFile*, decltype(&mkv_Close)> file(mkv_Open(&input, err, sizeof(err)), mkv_Close);
	if (!file) throw MatroskaException(err);

	// Get info
	unsigned tracks = mkv_GetNumTracks(file);
	std::vector<unsigned> tracksFound;
	std::vector<std::string> tracksNames;

	// Find tracks
	for (auto track : boost::irange(0u, tracks)) {
		auto trackInfo = mkv_GetTrackInfo(file, track);
		if (trackInfo->Type != 0x11 || trackInfo->CompEnabled) continue;

		// Known subtitle format
		std::string CodecID(trackInfo->CodecID);
		if (CodecID == "S_TEXT/SSA" || CodecID == "S_TEXT/ASS" || CodecID == "S_TEXT/UTF8") {
			tracksFound.push_back(track);
			tracksNames.emplace_back(agi::format("%d (%s %s)", track, CodecID, trackInfo->Language));
			if (trackInfo->Name) {
				tracksNames.back() += ": ";
				tracksNames.back() += trackInfo->Name;
			}
		}
	}

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

	unsigned trackToRead;
	// 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"), to_wx(tracksNames));
		if (choice == -1)
			throw agi::UserCancelException("canceled");

		trackToRead = tracksFound[choice];
	}

	// Picked track
	mkv_SetTrackMask(file, ~(1 << trackToRead));
	auto trackInfo = mkv_GetTrackInfo(file, trackToRead);
	std::string CodecID(trackInfo->CodecID);
	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
		std::string priv((const char *)trackInfo->CodecPrivate, trackInfo->CodecPrivateSize);

		// Load into file
		boost::char_separator<char> sep("\r\n");
		for (auto const& cur : boost::tokenizer<boost::char_separator<char>>(priv, sep))
			parser.AddLine(cur);
	}
	// Load default if it's SRT
	else {
		target->LoadDefault(false);
		parser.AddLine("[Events]");
	}

	// Read timecode scale
	auto segInfo = mkv_GetFileInfo(file);
	int64_t timecodeScale = mkv_TruncFloat(trackInfo->TimecodeScale) * segInfo->TimecodeScale;

	// Progress bar
	auto 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); });
}

bool MatroskaWrapper::HasSubtitles(agi::fs::path const& filename) {
	char err[2048];
	try {
		MkvStdIO input(filename);
		agi::scoped_holder<MatroskaFile*, decltype(&mkv_Close)> file(mkv_Open(&input, err, sizeof(err)), mkv_Close);
		if (!file) return false;

		// Find tracks
		auto tracks = mkv_GetNumTracks(file);
		for (auto track : boost::irange(0u, tracks)) {
			auto trackInfo = mkv_GetTrackInfo(file, track);

			if (trackInfo->Type == 0x11 && !trackInfo->CompEnabled) {
				std::string CodecID(trackInfo->CodecID);
				if (CodecID == "S_TEXT/SSA" || CodecID == "S_TEXT/ASS" || CodecID == "S_TEXT/UTF8")
					return true;
			}
		}
	}
	catch (...) {
		// We don't care about why we couldn't read subtitles here
	}

	return false;
}