Aegisub/aegisub/audio_provider_pcm.h
Niels Martin Hansen 08910b5a9d Make PCM audio provider access the file memory mapped instead of through regular file access, per bug #686. Tested to work on Windows.
I've also added a POSIX implementation but it's untested and might not even build.
The implementation is not actually thread safe, but this shouldn't be a problem in most cases, yet. It should still be fixed at some point.

Originally committed to SVN as r2130.
2008-03-24 00:10:09 +00:00

99 lines
3.4 KiB
C++

// 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);