The Tor Browser: content/media/AudioCompactor.cpp@44a2da4a2ab2

Replace accessor implementation with direct member state manipulation, by
request https://trac.torproject.org/projects/tor/ticket/9701#comment:32

     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

    11 namespace mozilla {

    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 }

    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 }

    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);

    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   }

    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 }

    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");

    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);

    63   NS_ASSERTION((mNextByte + bytes) <= mSourceBytes,

    64                "tried to copy beyond source buffer");

    65   NS_ASSERTION(bytes <= bufferBytes, "tried to copy beyond destination buffer");

    67   memcpy(aBuffer, mSource + mNextByte, bytes);

    69   mNextByte += bytes;

    70   return frames;

    71 }

    73 } // namespace mozilla

The Tor Browser / file revision