Aegisub/libaegisub/audio/provider_ram.cpp

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// Copyright (c) 2014, Thomas Goyne <plorkyeran@aegisub.org>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
// Aegisub Project http://www.aegisub.org/
#include "libaegisub/audio/provider.h"
#include "libaegisub/make_unique.h"
#include <array>
#include <boost/container/stable_vector.hpp>
#include <thread>
namespace {
using namespace agi;
#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 AudioProviderError("Not enough memory available to cache in RAM");
}
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;
}
}
}
namespace agi {
std::unique_ptr<AudioProvider> CreateRAMAudioProvider(std::unique_ptr<AudioProvider> src) {
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return agi::make_unique<RAMAudioProvider>(std::move(src));
}
}