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/core/fpdfapi/font/cpdf_cmap.cpp b/core/fpdfapi/font/cpdf_cmap.cpp
index 659139f687..0d3745e44a 100644
--- a/core/fpdfapi/font/cpdf_cmap.cpp
+++ b/core/fpdfapi/font/cpdf_cmap.cpp
@@ -253,12 +253,12 @@ void CPDF_CMap::LoadPredefined(CPDF_CMapManager* pMgr,
   m_PredefinedCMap = bsName;
   if (m_PredefinedCMap == "Identity-H" || m_PredefinedCMap == "Identity-V") {
     m_Coding = CIDCODING_CID;
-    m_bVertical = bsName[9] == 'V';
+    m_bVertical = bsName.Last() == 'V';
     m_bLoaded = true;
     return;
   }
   CFX_ByteString cmapid = m_PredefinedCMap;
-  m_bVertical = cmapid.Right(1) == "V";
+  m_bVertical = cmapid.Last() == 'V';
   if (cmapid.GetLength() > 2) {
     cmapid = cmapid.Left(cmapid.GetLength() - 2);
   }