diff options
Diffstat (limited to 'image/Downscaler.cpp')
| -rw-r--r-- | image/Downscaler.cpp | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/image/Downscaler.cpp b/image/Downscaler.cpp index 18f09c596..2ded487a5 100644 --- a/image/Downscaler.cpp +++ b/image/Downscaler.cpp @@ -231,6 +231,7 @@ Downscaler::CommitRow() int32_t inLineToRead = filterOffset + mLinesInBuffer; MOZ_ASSERT(mCurrentInLine <= inLineToRead, "Reading past end of input"); if (mCurrentInLine == inLineToRead) { + MOZ_RELEASE_ASSERT(mLinesInBuffer < mWindowCapacity, "Need more rows than capacity!"); skia::ConvolveHorizontally(mRowBuffer.get(), *mXFilter, mWindow[mLinesInBuffer++], mHasAlpha, supports_sse2() || supports_mmi()); @@ -239,7 +240,7 @@ Downscaler::CommitRow() MOZ_ASSERT(mCurrentOutLine < mTargetSize.height, "Writing past end of output"); - while (mLinesInBuffer == filterLength) { + while (mLinesInBuffer >= filterLength) { DownscaleInputLine(); if (mCurrentOutLine == mTargetSize.height) { @@ -340,9 +341,14 @@ Downscaler::DownscaleInputLine() // Shift the buffer. We're just moving pointers here, so this is cheap. mLinesInBuffer -= diff; - mLinesInBuffer = max(mLinesInBuffer, 0); - for (int32_t i = 0; i < mLinesInBuffer; ++i) { - swap(mWindow[i], mWindow[filterLength - mLinesInBuffer + i]); + mLinesInBuffer = min(max(mLinesInBuffer, 0), mWindowCapacity); + + // If we already have enough rows to satisfy the filter, there is no need + // to swap as we won't be writing more before the next convolution. + if (filterLength > mLinesInBuffer) { + for (int32_t i = 0; i < mLinesInBuffer; ++i) { + swap(mWindow[i], mWindow[filterLength - mLinesInBuffer + i]); + } } } |