commit 68545dc47e59c42fd953d810e255027a0790bd5f
author Tom Sepez <tsepez@chromium.org> Thu Jun 17 19:29:58 2021 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Thu Jun 17 19:29:58 2021 +0000
tree c00c818a35c7d622deb89a4d02071fcae4d3216c
parent 532886d1e7103c988210b1e68a6d334e0de99f45

Early return for zero dest_len in WeightTable::CalculateWeights().

Avoid a possible floating div-by-zero later on and return a nice empty
table for this case.

Change-Id: Ib8bdc732f778e1368a32cb0e60545b443d3df1c6
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/82171
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

core/fxge/dib/cstretchengine.cpp

diff --git a/core/fxge/dib/cstretchengine.cpp b/core/fxge/dib/cstretchengine.cpp
index 5b2ff3b..ade1c81 100644
--- a/core/fxge/dib/cstretchengine.cpp
+++ b/core/fxge/dib/cstretchengine.cpp
@@ -67,6 +67,9 @@
   m_ItemSizeBytes = 0;
   m_WeightTablesSizeBytes = 0;
   m_WeightTables.clear();
+  if (dest_len == 0)
+    return true;
+
   if (dest_min > dest_max)
     return false;
 

core/fxge/dib/cstretchengine_unittest.cpp

diff --git a/core/fxge/dib/cstretchengine_unittest.cpp b/core/fxge/dib/cstretchengine_unittest.cpp
index 6db7667..2053155 100644
--- a/core/fxge/dib/cstretchengine_unittest.cpp
+++ b/core/fxge/dib/cstretchengine_unittest.cpp
@@ -135,3 +135,9 @@
   CStretchEngine::WeightTable table;
   ASSERT_TRUE(table.CalculateWeights(100, 0, 100, 0, 0, 0, options));
 }
+
+TEST(CStretchEngine, ZeroLengthDest) {
+  FXDIB_ResampleOptions options;
+  CStretchEngine::WeightTable table;
+  ASSERT_TRUE(table.CalculateWeights(0, 0, 0, 100, 0, 100, options));
+}