diff options
Diffstat (limited to 'image/DownscalingFilter.h')
| -rw-r--r-- | image/DownscalingFilter.h | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/image/DownscalingFilter.h b/image/DownscalingFilter.h index 6b0d3b26b..1485b85c2 100644 --- a/image/DownscalingFilter.h +++ b/image/DownscalingFilter.h @@ -246,6 +246,7 @@ protected: int32_t inputRowToRead = filterOffset + mRowsInWindow; MOZ_ASSERT(mInputRow <= inputRowToRead, "Reading past end of input"); if (mInputRow == inputRowToRead) { + MOZ_RELEASE_ASSERT(mRowsInWindow < mWindowCapacity, "Need more rows than capacity!"); skia::ConvolveHorizontally(mRowBuffer.get(), *mXFilter, mWindow[mRowsInWindow++], mHasAlpha, supports_sse2() || supports_mmi()); @@ -254,7 +255,7 @@ protected: MOZ_ASSERT(mOutputRow < mNext.InputSize().height, "Writing past end of output"); - while (mRowsInWindow == filterLength) { + while (mRowsInWindow >= filterLength) { DownscaleInputRow(); if (mOutputRow == mNext.InputSize().height) { @@ -330,9 +331,14 @@ private: // Shift the buffer. We're just moving pointers here, so this is cheap. mRowsInWindow -= diff; - mRowsInWindow = std::max(mRowsInWindow, 0); - for (int32_t i = 0; i < mRowsInWindow; ++i) { - std::swap(mWindow[i], mWindow[filterLength - mRowsInWindow + i]); + mRowsInWindow = std::min(std::max(mRowsInWindow, 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 > mRowsInWindow) { + for (int32_t i = 0; i < mRowsInWindow; ++i) { + std::swap(mWindow[i], mWindow[filterLength - mRowsInWindow + i]); + } } } |