Rewrite IsHyphen using string operations

The existing code did end of range checks by making sure that the 
value was never less then 0. This isn't correct when using an unsigned
type, since 0 - 1 will wrap around to the max possible value, and
thus still be less then 0. Additionally the existing code was hard to
follow due to the complexity of some of the low level operations being 
performed.

It has been rewritten using higher level string operations to make it
clearer and correct.

BUG=chromium:763256

Change-Id: Ib8bf5ca0e29e73724c4a1c4781362e8a8fc30149
Reviewed-on: https://pdfium-review.googlesource.com/13690
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/core/fxcrt/cfx_widestring_unittest.cpp b/core/fxcrt/cfx_widestring_unittest.cpp
index 7b12d50601..1c8aca9aca 100644
--- a/core/fxcrt/cfx_widestring_unittest.cpp
+++ b/core/fxcrt/cfx_widestring_unittest.cpp
@@ -1038,6 +1038,14 @@ TEST(fxcrt, WideStringCAnyAllNoneOf) {
   EXPECT_FALSE(pdfium::ContainsValue(str, L'z'));
 }
 
+TEST(fxcrt, WideStringCTrimmedRight) {
+  CFX_WideStringC fred(L"FRED");
+  EXPECT_EQ(L"FRED", fred.TrimmedRight(L'E'));
+  EXPECT_EQ(L"FRE", fred.TrimmedRight(L'D'));
+  CFX_WideStringC fredd(L"FREDD");
+  EXPECT_EQ(L"FRE", fred.TrimmedRight(L'D'));
+}
+
 TEST(fxcrt, WideStringFormatWidth) {
   {
     CFX_WideString str;