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Adds band-aid for possible arithmetic overflow #127

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Merged
dimitris-c merged 1 commit into from
Dec 8, 2025
Merged

Adds band-aid for possible arithmetic overflow #127

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44 changes: 41 additions & 3 deletions AudioStreaming/Streaming/AudioPlayer/Processors/AudioPlayerRenderProcessor.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,12 @@ final class AudioPlayerRenderProcessor: NSObject {
let frameSizeInBytes = bufferContext.sizeInBytes
let used = bufferContext.frameUsedCount
let start = bufferContext.frameStartIndex
#if DEBUG
assert(start < bufferContext.totalFrameCount,
"frameStartIndex (\(start)) >= totalFrameCount (\(bufferContext.totalFrameCount)) - logic error!")
assert(used <= bufferContext.totalFrameCount,
"frameUsedCount (\(used)) > totalFrameCount (\(bufferContext.totalFrameCount)) - logic error!")
#endif
let end = (bufferContext.frameStartIndex + bufferContext.frameUsedCount) % bufferContext.totalFrameCount
let signal = rendererContext.waiting.value && used < bufferContext.totalFrameCount / 2

Expand Down Expand Up @@ -122,12 +128,33 @@ final class AudioPlayerRenderProcessor: NSObject {
totalFramesCopied = framesToCopy

rendererContext.lock.lock()
#if DEBUG
if totalFramesCopied > bufferContext.frameUsedCount {
Logger.debug("Buffer race: tried to consume %d frames but only %d available (reset likely occurred)",
category: .audioRendering,
args: totalFramesCopied, bufferContext.frameUsedCount)
}
#endif
bufferContext.frameStartIndex = (bufferContext.frameStartIndex + totalFramesCopied) % bufferContext.totalFrameCount
bufferContext.frameUsedCount -= totalFramesCopied
if totalFramesCopied <= bufferContext.frameUsedCount {
bufferContext.frameUsedCount -= totalFramesCopied
} else {
bufferContext.frameUsedCount = 0
}
rendererContext.lock.unlock()

} else {
let frameToCopy = min(inNumberFrames, bufferContext.totalFrameCount - start)
let frameToCopy: UInt32
if start < bufferContext.totalFrameCount {
frameToCopy = min(inNumberFrames, bufferContext.totalFrameCount - start)
} else {
#if DEBUG
Logger.debug("Buffer race: start index %d >= totalFrameCount %d (reset likely occurred)",
category: .audioRendering,
args: start, bufferContext.totalFrameCount)
#endif
frameToCopy = 0
}
bufferList.mBuffers.mNumberChannels = 2
bufferList.mBuffers.mDataByteSize = frameSizeInBytes * frameToCopy

Expand Down Expand Up @@ -160,8 +187,19 @@ final class AudioPlayerRenderProcessor: NSObject {
totalFramesCopied = frameToCopy + moreFramesToCopy

rendererContext.lock.lock()
#if DEBUG
if totalFramesCopied > bufferContext.frameUsedCount {
Logger.debug("Buffer race: tried to consume %d frames but only %d available (reset likely occurred)",
category: .audioRendering,
args: totalFramesCopied, bufferContext.frameUsedCount)
}
#endif
bufferContext.frameStartIndex = (bufferContext.frameStartIndex + totalFramesCopied) % bufferContext.totalFrameCount
bufferContext.frameUsedCount -= totalFramesCopied
if totalFramesCopied <= bufferContext.frameUsedCount {
bufferContext.frameUsedCount -= totalFramesCopied
} else {
bufferContext.frameUsedCount = 0
}
rendererContext.lock.unlock()
}

Expand Down
8 changes: 7 additions & 1 deletion AudioStreaming/Streaming/Helpers/BufferContext.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,13 @@ final class BufferContext {
var frameUsedCount: UInt32 = 0

var end: UInt32 {
(frameStartIndex + frameUsedCount) % totalFrameCount
#if DEBUG
assert(frameStartIndex < totalFrameCount,
"frameStartIndex (\(frameStartIndex)) exceeds totalFrameCount (\(totalFrameCount)) - logic error!")
assert(frameUsedCount <= totalFrameCount,
"frameUsedCount (\(frameUsedCount)) exceeds totalFrameCount (\(totalFrameCount)) - logic error!")
#endif
return (frameStartIndex + frameUsedCount) % totalFrameCount
}

init(sizeInBytes: UInt32, totalFrameCount: UInt32) {
Expand Down