The Tor Browser / file comparison
comparison: content/media/AudioCompactor.cpp
content/media/AudioCompactor.cpp
- branch
- TOR_BUG_9701
- changeset 13
- 44a2da4a2ab2
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| -1:000000000000 | 0:bbe9fb3f2bfe |
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| 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" | |
| 9 #endif | |
| 10 | |
| 11 namespace mozilla { | |
| 12 | |
| 13 static size_t | |
| 14 MallocGoodSize(size_t aSize) | |
| 15 { | |
| 16 # if defined(MOZ_MEMORY) | |
| 17 return malloc_good_size(aSize); | |
| 18 # else | |
| 19 return aSize; | |
| 20 # endif | |
| 21 } | |
| 22 | |
| 23 static size_t | |
| 24 TooMuchSlop(size_t aSize, size_t aAllocSize, size_t aMaxSlop) | |
| 25 { | |
| 26 // If the allocated size is less then our target size, then we | |
| 27 // are chunking. This means it will be completely filled with | |
| 28 // zero slop. | |
| 29 size_t slop = (aAllocSize > aSize) ? (aAllocSize - aSize) : 0; | |
| 30 return slop > aMaxSlop; | |
| 31 } | |
| 32 | |
| 33 uint32_t | |
| 34 AudioCompactor::GetChunkSamples(uint32_t aFrames, uint32_t aChannels, | |
| 35 size_t aMaxSlop) | |
| 36 { | |
| 37 size_t size = AudioDataSize(aFrames, aChannels); | |
| 38 size_t chunkSize = MallocGoodSize(size); | |
| 39 | |
| 40 // Reduce the chunk size until we meet our slop goal or the chunk | |
| 41 // approaches an unreasonably small size. | |
| 42 while (chunkSize > 64 && TooMuchSlop(size, chunkSize, aMaxSlop)) { | |
| 43 chunkSize = MallocGoodSize(chunkSize / 2); | |
| 44 } | |
| 45 | |
| 46 // Calculate the number of samples based on expected malloc size | |
| 47 // in order to allow as many frames as possible to be packed. | |
| 48 return chunkSize / sizeof(AudioDataValue); | |
| 49 } | |
| 50 | |
| 51 uint32_t | |
| 52 AudioCompactor::NativeCopy::operator()(AudioDataValue *aBuffer, | |
| 53 uint32_t aSamples) | |
| 54 { | |
| 55 NS_ASSERTION(aBuffer, "cannot copy to null buffer pointer"); | |
| 56 NS_ASSERTION(aSamples, "cannot copy zero values"); | |
| 57 | |
| 58 size_t bufferBytes = aSamples * sizeof(AudioDataValue); | |
| 59 size_t maxBytes = std::min(bufferBytes, mSourceBytes - mNextByte); | |
| 60 uint32_t frames = maxBytes / BytesPerFrame(mChannels); | |
| 61 size_t bytes = frames * BytesPerFrame(mChannels); | |
| 62 | |
| 63 NS_ASSERTION((mNextByte + bytes) <= mSourceBytes, | |
| 64 "tried to copy beyond source buffer"); | |
| 65 NS_ASSERTION(bytes <= bufferBytes, "tried to copy beyond destination buffer"); | |
| 66 | |
| 67 memcpy(aBuffer, mSource + mNextByte, bytes); | |
| 68 | |
| 69 mNextByte += bytes; | |
| 70 return frames; | |
| 71 } | |
| 72 | |
| 73 } // namespace mozilla |
