mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-08 20:47:44 +00:00
74 lines
2.3 KiB
C++
74 lines
2.3 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
#include "AudioCompactor.h"
|
|
#if defined(MOZ_MEMORY)
|
|
# include "mozmemory.h"
|
|
#endif
|
|
|
|
namespace mozilla {
|
|
|
|
static size_t
|
|
MallocGoodSize(size_t aSize)
|
|
{
|
|
# if defined(MOZ_MEMORY)
|
|
return malloc_good_size(aSize);
|
|
# else
|
|
return aSize;
|
|
# endif
|
|
}
|
|
|
|
static size_t
|
|
TooMuchSlop(size_t aSize, size_t aAllocSize, size_t aMaxSlop)
|
|
{
|
|
// If the allocated size is less then our target size, then we
|
|
// are chunking. This means it will be completely filled with
|
|
// zero slop.
|
|
size_t slop = (aAllocSize > aSize) ? (aAllocSize - aSize) : 0;
|
|
return slop > aMaxSlop;
|
|
}
|
|
|
|
uint32_t
|
|
AudioCompactor::GetChunkSamples(uint32_t aFrames, uint32_t aChannels,
|
|
size_t aMaxSlop)
|
|
{
|
|
size_t size = AudioDataSize(aFrames, aChannels);
|
|
size_t chunkSize = MallocGoodSize(size);
|
|
|
|
// Reduce the chunk size until we meet our slop goal or the chunk
|
|
// approaches an unreasonably small size.
|
|
while (chunkSize > 64 && TooMuchSlop(size, chunkSize, aMaxSlop)) {
|
|
chunkSize = MallocGoodSize(chunkSize / 2);
|
|
}
|
|
|
|
// Calculate the number of samples based on expected malloc size
|
|
// in order to allow as many frames as possible to be packed.
|
|
return chunkSize / sizeof(AudioDataValue);
|
|
}
|
|
|
|
uint32_t
|
|
AudioCompactor::NativeCopy::operator()(AudioDataValue *aBuffer,
|
|
uint32_t aSamples)
|
|
{
|
|
NS_ASSERTION(aBuffer, "cannot copy to null buffer pointer");
|
|
NS_ASSERTION(aSamples, "cannot copy zero values");
|
|
|
|
size_t bufferBytes = aSamples * sizeof(AudioDataValue);
|
|
size_t maxBytes = std::min(bufferBytes, mSourceBytes - mNextByte);
|
|
uint32_t frames = maxBytes / BytesPerFrame(mChannels);
|
|
size_t bytes = frames * BytesPerFrame(mChannels);
|
|
|
|
NS_ASSERTION((mNextByte + bytes) <= mSourceBytes,
|
|
"tried to copy beyond source buffer");
|
|
NS_ASSERTION(bytes <= bufferBytes, "tried to copy beyond destination buffer");
|
|
|
|
memcpy(aBuffer, mSource + mNextByte, bytes);
|
|
|
|
mNextByte += bytes;
|
|
return frames;
|
|
}
|
|
|
|
} // namespace mozilla
|