mirror of https://github.com/odrling/Aegisub
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.
This commit is contained in:
Niels Martin Hansen
parent
3fb93565f5
commit
08910b5a9d
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@ -1,4 +1,4 @@
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// Copyright (c) 2007, Niels Martin Hansen
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// Copyright (c) 2007-2008, Niels Martin Hansen
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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@ -40,12 +40,160 @@
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#include "utils.h"
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#include <stdint.h>
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#ifndef _WINDOWS
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#include <sys/mman.h>
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#include <sys/fcntl.h>
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#include <sys/stat.h>
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#endif
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PCMAudioProvider::PCMAudioProvider(const wxString &filename)
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{
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#ifdef _WINDOWS
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file_handle = CreateFile(
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filename.c_str(),
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FILE_READ_DATA,
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FILE_SHARE_READ|FILE_SHARE_WRITE,
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0,
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OPEN_EXISTING,
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FILE_ATTRIBUTE_NORMAL|FILE_FLAG_RANDOM_ACCESS,
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0);
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if (file_handle == INVALID_HANDLE_VALUE) {
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wxLogWarning(_T("PCM audio provider: Could not open audio file for reading (%d)"), GetLastError());
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throw _T("PCM audio provider: Could not open audio file for reading");
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}
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LARGE_INTEGER li_file_size = {0};
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if (!GetFileSizeEx(file_handle, &li_file_size)) {
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CloseHandle(file_handle);
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throw _T("PCM audio provider: Failed getting file size");
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}
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file_size = li_file_size.QuadPart;
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file_mapping = CreateFileMapping(
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file_handle,
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0,
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PAGE_READONLY,
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0, 0,
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0);
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if (file_mapping == 0) {
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CloseHandle(file_handle);
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throw _T("PCM audio provider: Failed creating file mapping");
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}
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current_mapping = 0;
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#else
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file_handle = open(filename.mb_str(wxConvFilename), O_RDONLY);
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if (file_handle == -1) {
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throw _T("PCM audio provider: Could not open audio file for reading");
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}
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struct stat filestats = {0};
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if (fstat(file_handle, &filestats)) {
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close(file_handle);
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throw _T("PCM audio provider: Could not stat file to get size");
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}
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file_size = filestats.st_size;
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current_mapping = 0;
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#endif
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}
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PCMAudioProvider::~PCMAudioProvider()
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{
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#ifdef _WINDOWS
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if (current_mapping) {
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UnmapViewOfFile(current_mapping);
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}
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CloseHandle(file_mapping);
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CloseHandle(file_handle);
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#else
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if (current_mapping) {
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munmap(current_mapping, mapping_length);
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}
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close(file_handle);
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#endif
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}
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char * PCMAudioProvider::EnsureRangeAccessible(int64_t range_start, int64_t range_length)
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{
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if (range_start + range_length > file_size) {
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throw _T("PCM audio provider: Attempted to map beyond end of file");
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}
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// Check whether the requested range is already visible
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if (range_start < mapping_start || range_start+range_length > mapping_start+mapping_length) {
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// It's not visible, change the current mapping
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if (current_mapping) {
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#ifdef _WINDOWS
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UnmapViewOfFile(current_mapping);
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#else
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munmap(current_mapping, mapping_length);
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#endif
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}
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// Align range start on a 1 MB boundary and go 16 MB back
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mapping_start = (range_start & ~0xFFFFF) - 0x1000000;
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if (mapping_start < 0) mapping_start = 0;
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#ifdef _WINDOWS
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# if defined(_M_X64) || defined(_M_IA64)
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// Make 2 GB mappings by default on 64 bit archs
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mapping_length = 0x80000000;
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# else
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// Make 256 MB mappings by default on x86
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mapping_length = 0x10000000;
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# endif
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#else
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// 256 MB
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mapping_length = 0x10000000;
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#endif
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if (mapping_length > file_size) mapping_length = (size_t)(file_size - mapping_start);
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// Hopefully this should ensure that small files are always mapped in their entirety
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#ifdef _WINDOWS
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current_mapping = MapViewOfFile(
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file_mapping,
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FILE_MAP_READ,
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mapping_start >> 32, mapping_start & 0xFFFFFFFF,
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mapping_length);
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#else
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current_mapping = mmap(0, mapping_length, PROT_READ, MAP_PRIVATE, file_handle, mapping_start);
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#endif
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if (!current_mapping) {
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throw _T("PCM audio provider: Failed mapping a view of the file");
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}
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}
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assert(range_start >= mapping_start);
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ptrdiff_t rel_ofs = (ptrdiff_t)(range_start - mapping_start);
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return ((char*)current_mapping) + rel_ofs;
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}
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void PCMAudioProvider::GetAudio(void *buf, int64_t start, int64_t count)
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{
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// We'll be seeking in the file so state can become inconsistent
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wxMutexLocker _fml(filemutex);
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// Read blocks from the file
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size_t index = 0;
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while (count > 0 && index < index_points.size()) {
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@ -58,8 +206,10 @@ void PCMAudioProvider::GetAudio(void *buf, int64_t start, int64_t count)
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if (samples_can_do > count) samples_can_do = count;
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// Read as many samples we can
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file.Seek(ip.start_byte + (start - ip.start_sample) * bytes_per_sample * channels, wxFromStart);
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file.Read(buf, samples_can_do * bytes_per_sample * channels);
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char *src = EnsureRangeAccessible(
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ip.start_byte + (start - ip.start_sample) * bytes_per_sample * channels,
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samples_can_do * bytes_per_sample * channels);
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memcpy(buf, src, samples_can_do * bytes_per_sample * channels);
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// Update data
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buf = (char*)buf + samples_can_do * bytes_per_sample * channels;
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@ -111,15 +261,14 @@ private:
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public:
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RiffWavPCMAudioProvider(const wxString &_filename)
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: PCMAudioProvider(_filename)
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{
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filename = _filename;
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if (!file.Open(_filename, wxFile::read)) throw _T("RIFF PCM WAV audio provider: Unable to open file for reading");
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// Read header
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file.Seek(0);
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RIFFChunk header;
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if (file.Read(&header, sizeof(header)) < (ssize_t) sizeof(header)) throw _T("RIFF PCM WAV audio provider: file is too small to contain a RIFF header");
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// Assume we won't get files smaller than 256 bytes
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void *filestart = EnsureRangeAccessible(0, sizeof(RIFFChunk));
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RIFFChunk &header = *(RIFFChunk*)filestart;
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// Check that it's good
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if (strncmp(header.ch.type, "RIFF", 4)) throw _T("RIFF PCM WAV audio provider: File is not a RIFF file");
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@ -139,9 +288,7 @@ public:
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// Continue reading chunks until out of data
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while (data_left) {
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file.Seek(filepos);
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ChunkHeader ch;
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if (file.Read(&ch, sizeof(ch)) < (ssize_t) sizeof(ch)) break;
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ChunkHeader &ch = *(ChunkHeader*)EnsureRangeAccessible(filepos, sizeof(ChunkHeader));
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// Update counters
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data_left -= sizeof(ch);
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@ -151,8 +298,7 @@ public:
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if (got_fmt_header) throw _T("RIFF PCM WAV audio provider: Invalid file, multiple 'fmt ' chunks");
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got_fmt_header = true;
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fmtChunk fmt;
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if (file.Read(&fmt, sizeof(fmt)) < (ssize_t) sizeof(fmt)) throw _T("RIFF PCM WAV audio provider: File ended before end of 'fmt ' chunk");
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fmtChunk &fmt = *(fmtChunk*)EnsureRangeAccessible(filepos, sizeof(fmtChunk));
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if (fmt.compression != 1) throw _T("RIFF PCM WAV audio provider: Can't use file, not PCM encoding");
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@ -279,8 +425,12 @@ AudioProvider *CreatePCMAudioProvider(const wxString &filename)
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// Try Microsoft/IBM RIFF WAV first
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// XXX: This is going to blow up if built on big endian archs
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try { provider = new RiffWavPCMAudioProvider(filename); }
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catch (...) { provider = 0; }
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try {
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provider = new RiffWavPCMAudioProvider(filename);
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}
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catch (...) {
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provider = 0;
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}
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if (provider && provider->GetChannels() > 1) {
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// Can't feed non-mono audio to the rest of the program.
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@ -1,4 +1,4 @@
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// Copyright (c) 2007, Niels Martin Hansen
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// Copyright (c) 2007-2008, Niels Martin Hansen
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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@ -44,13 +44,37 @@
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#include <wx/thread.h>
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#include <vector>
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#ifdef _WINDOWS
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#include <windows.h>
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#endif
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/////////////////////////////
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// Audio provider base class
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class PCMAudioProvider : public AudioProvider {
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private:
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#ifdef _WINDOWS
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// File handle and file mapping handle from Win32
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HANDLE file_handle;
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HANDLE file_mapping;
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// Pointer to current area mapped into memory
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void *current_mapping;
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// Byte indices in the file that the current mapping covers
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int64_t mapping_start;
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size_t mapping_length;
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#else
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int file_handle;
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void *current_mapping;
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off_t mapping_start;
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size_t mapping_length;
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#endif
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protected:
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wxMutex filemutex;
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wxFile file;
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PCMAudioProvider(const wxString &filename); // Create base object and open the file mapping
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virtual ~PCMAudioProvider(); // Closes the file mapping
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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
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int64_t file_size; // Size of the opened file
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// Hold data for an index point,
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// to support files where audio data are
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