Cleanup usages of Mid(foo, 1), Right(1), and Left(1)chromium/3203

Mid(foo, 1) is equivalent to [foo], if all you want is the character. Similarly
Left(1) is [0]. It is faster also, since it does not need to create intermediate
strings.

Right(1) is a touch more tricky, since it requires something like GetLength() ?
[GetLength() - 1] : 0;. A new method, Last() has been added to perform this
character extraction.

Multiple call sites have been updated to use more efficient/simpler
syntax. There are a number of call sites that use on these patterns, but based
on the surrounding context we actually need/want a string, so they have not been
modified.

Change-Id: I485a7f9c7b34c9bdacecada610158f996816afdd
Reviewed-on: https://pdfium-review.googlesource.com/12890
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/xfa/fxfa/parser/cxfa_resolveprocessor.cpp b/xfa/fxfa/parser/cxfa_resolveprocessor.cpp
index fe4605b4f0..15c3f14b23 100644
--- a/xfa/fxfa/parser/cxfa_resolveprocessor.cpp
+++ b/xfa/fxfa/parser/cxfa_resolveprocessor.cpp
@@ -661,9 +661,9 @@ void CXFA_ResolveProcessor::DoPredicateFilter(int32_t iCurIndex,
   ASSERT(iFoundCount == pdfium::CollectionSize<int32_t>(rnd.m_Objects));
   CFX_WideString wsExpression;
   XFA_SCRIPTLANGTYPE eLangType = XFA_SCRIPTLANGTYPE_Unkown;
-  if (wsCondition.Left(2) == L".[" && wsCondition.Right(1) == L"]") {
+  if (wsCondition.Left(2) == L".[" && wsCondition.Last() == L']') {
     eLangType = XFA_SCRIPTLANGTYPE_Formcalc;
-  } else if (wsCondition.Left(2) == L".(" && wsCondition.Right(1) == L")") {
+  } else if (wsCondition.Left(2) == L".(" && wsCondition.Last() == L')') {
     eLangType = XFA_SCRIPTLANGTYPE_Javascript;
   } else {
     return;