Aegisub/aegisub/src/audio_provider_pcm.h

// Copyright (c) 2007-2008, Niels Martin Hansen
// 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.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// -----------------------------------------------------------------------------
//
// AEGISUB
//
// Website: http://aegisub.cellosoft.com
// Contact: mailto:jiifurusu@gmail.com
//


#pragma once


///////////
// Headers
#include "include/aegisub/audio_provider.h"
#include <wx/file.h>
#include <wx/thread.h>
#include <vector>

#ifdef _WINDOWS
#include <windows.h>
#endif


/////////////////////////////
// Audio provider base class
class PCMAudioProvider : public AudioProvider {
private:
#ifdef _WINDOWS
	// File handle and file mapping handle from Win32
	HANDLE file_handle;
	HANDLE file_mapping;
	// Pointer to current area mapped into memory
	void *current_mapping;
	// Byte indices in the file that the current mapping covers
	int64_t mapping_start;
	size_t mapping_length;
#else
	int file_handle;
	void *current_mapping;
	off_t mapping_start;
	size_t mapping_length;
#endif

protected:
	PCMAudioProvider(const wxString &filename); // Create base object and open the file mapping
	virtual ~PCMAudioProvider(); // Closes the file mapping
	char * EnsureRangeAccessible(int64_t range_start, int64_t range_length); // Ensure that the given range of bytes are accessible in the file mapping and return a pointer to the first byte of the requested range

	int64_t file_size; // Size of the opened file

	// Hold data for an index point,
	// to support files where audio data are
	// split into multiple blocks.
	// Using int64_t's should be safe on most compilers,
	// wx defines wxFileOffset as int64 when possible
	struct IndexPoint {
		int64_t start_byte;
		int64_t start_sample;
		int64_t num_samples;
	};
	typedef std::vector<IndexPoint> IndexVector;
	IndexVector index_points;

public:
	virtual void GetAudio(void *buf, int64_t start, int64_t count);
};

// Construct the right PCM audio provider (if any) for the file
AudioProvider *CreatePCMAudioProvider(const wxString &filename);