commit 0471f74767e627f3805a0d7b61a73ae25065d5b3
author Alan Screen <awscreen@chromium.org> Wed Sep 11 20:30:58 2019 +0000
committer Chromium commit bot <commit-bot@chromium.org> Wed Sep 11 20:30:58 2019 +0000
tree 2ab427ac4e4a36f5e83823e6b7895a7ff802ceda
parent 0f6ef984bc72489d24d8c784cc9b199ceadfc87b

[FXCRT] Fix checks in FXSYS_round() for float precision

Resolve the floating precision error that happens at the edge of the
integer range.

Bug: chromium:611744
Change-Id: I01a0111740785fc68b59861b1c6ec07b6ccbef5d
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/60550
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

core/fxcrt/fx_system.cpp

diff --git a/core/fxcrt/fx_system.cpp b/core/fxcrt/fx_system.cpp
index 4f95b6a..f8a48db 100644
--- a/core/fxcrt/fx_system.cpp
+++ b/core/fxcrt/fx_system.cpp
@@ -93,7 +93,7 @@
     return 0;
   if (f < static_cast<float>(std::numeric_limits<int>::min()))
     return std::numeric_limits<int>::min();
-  if (f > static_cast<float>(std::numeric_limits<int>::max()))
+  if (f >= static_cast<float>(std::numeric_limits<int>::max()))
     return std::numeric_limits<int>::max();
   return static_cast<int>(round(f));
 }

core/fxcrt/fx_system_unittest.cpp

diff --git a/core/fxcrt/fx_system_unittest.cpp b/core/fxcrt/fx_system_unittest.cpp
index 83ac625..b28f18e 100644
--- a/core/fxcrt/fx_system_unittest.cpp
+++ b/core/fxcrt/fx_system_unittest.cpp
@@ -102,8 +102,7 @@
   EXPECT_EQ(2147483520, FXSYS_round(2.14748352e+9f));
 
   // Using a slightly larger value, expect to see it be capped at MAX_INT.
-  // Instead erroneously seeing a return of MIN_INT.  crbug.com/611744
-  EXPECT_EQ(-2147483648, FXSYS_round(2.14748365e+9f));
+  EXPECT_EQ(2147483647, FXSYS_round(2.14748365e+9f));
 
   EXPECT_EQ(2147483647, FXSYS_round(2.14748365e+10f));
   EXPECT_EQ(2147483647, FXSYS_round(std::numeric_limits<float>::max()));