Aegisub/src/audio_provider_ram.cpp

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// Copyright (c) 2005-2006, Rodrigo Braz Monteiro, Fredrik Mellbin
// 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 Project http://www.aegisub.org/
/// @file audio_provider_ram.cpp
/// @brief Caching audio provider using heap memory for backing
/// @ingroup audio_input
///
#include "include/aegisub/audio_provider.h"
#include "audio_controller.h"
#include <libaegisub/make_unique.h>
#include <array>
#include <boost/container/stable_vector.hpp>
#include <thread>
namespace {
#define CacheBits 22
#define CacheBlockSize (1 << CacheBits)
class RAMAudioProvider final : public AudioProviderWrapper {
#ifdef _MSC_VER
boost::container::stable_vector<char[CacheBlockSize]> blockcache;
#else
boost::container::stable_vector<std::array<char, CacheBlockSize>> blockcache;
#endif
std::atomic<bool> cancelled = {false};
std::thread decoder;
void FillBuffer(void *buf, int64_t start, int64_t count) const override;
public:
RAMAudioProvider(std::unique_ptr<AudioProvider> src)
: AudioProviderWrapper(std::move(src))
{
decoded_samples = 0;
try {
blockcache.resize((source->GetNumSamples() * source->GetBytesPerSample() + CacheBlockSize - 1) >> CacheBits);
}
catch (std::bad_alloc const&) {
throw agi::AudioCacheOpenError("Couldn't open audio, not enough ram available.");
}
decoder = std::thread([&] {
int64_t readsize = CacheBlockSize / source->GetBytesPerSample();
for (size_t i = 0; i < blockcache.size(); i++) {
if (cancelled) break;
auto actual_read = std::min<int64_t>(readsize, num_samples - i * readsize);
source->GetAudio(&blockcache[i][0], i * readsize, actual_read);
decoded_samples += actual_read;
}
});
}
~RAMAudioProvider() {
cancelled = true;
decoder.join();
}
};
void RAMAudioProvider::FillBuffer(void *buf, int64_t start, int64_t count) const {
auto charbuf = static_cast<char *>(buf);
for (int64_t bytes_remaining = count * bytes_per_sample; bytes_remaining; ) {
if (start >= decoded_samples) {
memset(charbuf, 0, bytes_remaining);
break;
}
const int i = (start * bytes_per_sample) >> CacheBits;
const int start_offset = (start * bytes_per_sample) & (CacheBlockSize-1);
const int read_size = std::min<int>(bytes_remaining, CacheBlockSize - start_offset);
memcpy(charbuf, &blockcache[i][start_offset], read_size);
charbuf += read_size;
bytes_remaining -= read_size;
start += read_size / bytes_per_sample;
}
}
}
std::unique_ptr<AudioProvider> CreateRAMAudioProvider(std::unique_ptr<AudioProvider> src) {
return agi::make_unique<RAMAudioProvider>(std::move(src));
}