From bd0e550e63c646dc5c515caf52aedad8bc29f9bd Mon Sep 17 00:00:00 2001
From: wolfbeast <mcwerewolf@gmail.com>
Date: Thu, 7 Jun 2018 06:21:57 +0200
Subject: Account for offsets when creating  buffers for image textures.

---
 gfx/layers/ImageDataSerializer.cpp | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

(limited to 'gfx/layers/ImageDataSerializer.cpp')

diff --git a/gfx/layers/ImageDataSerializer.cpp b/gfx/layers/ImageDataSerializer.cpp
index 08ed83bd9..db11e903c 100644
--- a/gfx/layers/ImageDataSerializer.cpp
+++ b/gfx/layers/ImageDataSerializer.cpp
@@ -83,6 +83,41 @@ ComputeYCbCrBufferSize(const gfx::IntSize& aYSize, const gfx::IntSize& aCbCrSize
   return ComputeYCbCrBufferSize(aYSize, aYSize.width, aCbCrSize, aCbCrSize.width);
 }
 
+uint32_t
+ComputeYCbCrBufferSize(const gfx::IntSize& aYSize, const gfx::IntSize& aCbCrSize,
+                       uint32_t aYOffset, uint32_t aCbOffset, uint32_t aCrOffset)
+{
+  MOZ_ASSERT(aYSize.height >= 0 && aYSize.width >= 0);
+
+  int32_t yStride = aYSize.width;
+  int32_t cbCrStride = aCbCrSize.width;
+  if (aYSize.height < 0 || aYSize.width < 0 || aCbCrSize.height < 0 || aCbCrSize.width < 0 ||
+      !gfx::Factory::AllowedSurfaceSize(IntSize(yStride, aYSize.height)) ||
+      !gfx::Factory::AllowedSurfaceSize(IntSize(cbCrStride, aCbCrSize.height))) {
+    return 0;
+  }
+
+  uint32_t yLength = GetAlignedStride<4>(yStride, aYSize.height);
+  uint32_t cbCrLength = GetAlignedStride<4>(cbCrStride, aCbCrSize.height);
+  if (yLength == 0 || cbCrLength == 0) {
+    return 0;
+  }
+
+  CheckedInt<uint32_t> yEnd = aYOffset;
+  yEnd += yLength;
+  CheckedInt<uint32_t> cbEnd = aCbOffset;
+  cbEnd += cbCrLength;
+  CheckedInt<uint32_t> crEnd = aCrOffset;
+  crEnd += cbCrLength;
+
+  if (!yEnd.isValid() || !cbEnd.isValid() || !crEnd.isValid() ||
+      yEnd.value() > aCbOffset || cbEnd.value() > aCrOffset) {
+    return 0;
+  }
+
+  return crEnd.value();
+}
+
 uint32_t
 ComputeYCbCrBufferSize(uint32_t aBufferSize)
 {
-- 
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