Replace raw value for constant error value in string operations

Currently Find() and other methods that return a FX_STRSIZE return -1
to indicate error/failure. This means that there is a lot of magic
numbers and magic checks floating around. The standard library for
similar operations uses a npos constant. This CL implements
FX_STRNPOS, and replaces usages of magic number checking. It also does
some type cleanup along the way where it was obvious that FX_STRSIZE
should be being used.

Removing the magic numbers should make eventually changing FX_STRSIZE
to be unsigned easier in the future.

BUG=pdfium:828

Change-Id: I67e481e44cf2f75a1698afa8fbee4f375a74c490
Reviewed-on: https://pdfium-review.googlesource.com/9651
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/fpdfsdk/fpdfppo.cpp b/fpdfsdk/fpdfppo.cpp
index beab7d87d3..bf52932a1d 100644
--- a/fpdfsdk/fpdfppo.cpp
+++ b/fpdfsdk/fpdfppo.cpp
@@ -80,20 +80,20 @@ bool ParserPageRangeString(CFX_ByteString rangstring,
   int nLength = rangstring.GetLength();
   CFX_ByteString cbCompareString("0123456789-,");
   for (int i = 0; i < nLength; ++i) {
-    if (cbCompareString.Find(rangstring[i]) == -1)
+    if (cbCompareString.Find(rangstring[i]) == FX_STRNPOS)
       return false;
   }
 
   CFX_ByteString cbMidRange;
-  int nStringFrom = 0;
-  int nStringTo = 0;
+  FX_STRSIZE nStringFrom = 0;
+  FX_STRSIZE nStringTo = 0;
   while (nStringTo < nLength) {
     nStringTo = rangstring.Find(',', nStringFrom);
-    if (nStringTo == -1)
+    if (nStringTo == FX_STRNPOS)
       nStringTo = nLength;
     cbMidRange = rangstring.Mid(nStringFrom, nStringTo - nStringFrom);
-    int nMid = cbMidRange.Find('-');
-    if (nMid == -1) {
+    FX_STRSIZE nMid = cbMidRange.Find('-');
+    if (nMid == FX_STRNPOS) {
       long lPageNum = atol(cbMidRange.c_str());
       if (lPageNum <= 0 || lPageNum > nCount)
         return false;