1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 #include "AudioCompactor.h"
7 #if defined(MOZ_MEMORY)
8 # include "mozmemory.h"
13 static size_t MallocGoodSize(size_t aSize
) {
14 #if defined(MOZ_MEMORY)
15 return malloc_good_size(aSize
);
21 static size_t TooMuchSlop(size_t aSize
, size_t aAllocSize
, size_t aMaxSlop
) {
22 // If the allocated size is less then our target size, then we
23 // are chunking. This means it will be completely filled with
25 size_t slop
= (aAllocSize
> aSize
) ? (aAllocSize
- aSize
) : 0;
26 return slop
> aMaxSlop
;
29 uint32_t AudioCompactor::GetChunkSamples(uint32_t aFrames
, uint32_t aChannels
,
31 size_t size
= AudioDataSize(aFrames
, aChannels
);
32 size_t chunkSize
= MallocGoodSize(size
);
34 // Reduce the chunk size until we meet our slop goal or the chunk
35 // approaches an unreasonably small size.
36 while (chunkSize
> 64 && TooMuchSlop(size
, chunkSize
, aMaxSlop
)) {
37 chunkSize
= MallocGoodSize(chunkSize
/ 2);
40 // Calculate the number of samples based on expected malloc size
41 // in order to allow as many frames as possible to be packed.
42 return chunkSize
/ sizeof(AudioDataValue
);
45 uint32_t AudioCompactor::NativeCopy::operator()(AudioDataValue
* aBuffer
,
47 NS_ASSERTION(aBuffer
, "cannot copy to null buffer pointer");
48 NS_ASSERTION(aSamples
, "cannot copy zero values");
50 size_t bufferBytes
= aSamples
* sizeof(AudioDataValue
);
51 size_t maxBytes
= std::min(bufferBytes
, mSourceBytes
- mNextByte
);
52 uint32_t frames
= maxBytes
/ BytesPerFrame(mChannels
);
53 size_t bytes
= frames
* BytesPerFrame(mChannels
);
55 NS_ASSERTION((mNextByte
+ bytes
) <= mSourceBytes
,
56 "tried to copy beyond source buffer");
57 NS_ASSERTION(bytes
<= bufferBytes
, "tried to copy beyond destination buffer");
59 memcpy(aBuffer
, mSource
+ mNextByte
, bytes
);
65 } // namespace mozilla