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>

3 files changed, 9 insertions, 6 deletions

diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
index 62b10c9149..e9676b1115 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
@@ -186,8 +186,10 @@ TEST_F(CPDF_PageContentGeneratorTest, ProcessStandardText) {
   std::ostringstream buf;
   TestProcessText(&generator, &buf, pTextObj.get());
   CFX_ByteString textString(buf);
-  int firstResourceAt = textString.Find('/') + 1;
-  int secondResourceAt = textString.ReverseFind('/') + 1;
+  FX_STRSIZE firstResourceAt = textString.Find('/') + 1;
+  FX_STRSIZE secondResourceAt = textString.ReverseFind('/') + 1;
+  EXPECT_NE(FX_STRNPOS, firstResourceAt);
+  EXPECT_NE(FX_STRNPOS, secondResourceAt);
   CFX_ByteString firstString = textString.Left(firstResourceAt);
   CFX_ByteString midString =
       textString.Mid(firstResourceAt, secondResourceAt - firstResourceAt);
@@ -252,7 +254,8 @@ TEST_F(CPDF_PageContentGeneratorTest, ProcessText) {
   }
 
   CFX_ByteString textString(buf);
-  int firstResourceAt = textString.Find('/') + 1;
+  FX_STRSIZE firstResourceAt = textString.Find('/') + 1;
+  EXPECT_NE(FX_STRNPOS, firstResourceAt);
   CFX_ByteString firstString = textString.Left(firstResourceAt);
   CFX_ByteString lastString =
       textString.Right(textString.GetLength() - firstResourceAt);
diff --git a/core/fpdfapi/page/cpdf_streamcontentparser.cpp b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
index 288f9d57a8..692de0f5eb 100644
--- a/core/fpdfapi/page/cpdf_streamcontentparser.cpp
+++ b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
@@ -316,7 +316,7 @@ void CPDF_StreamContentParser::AddNameParam(const CFX_ByteStringC& bsName) {
         m_pDocument->GetByteStringPool(), PDF_NameDecode(bsName));
   } else {
     param.m_Type = ContentParam::NAME;
-    if (bsName.Find('#') == -1) {
+    if (bsName.Find('#') == FX_STRNPOS) {
       memcpy(param.m_Name.m_Buffer, bsName.raw_str(), bsName.GetLength());
       param.m_Name.m_Len = bsName.GetLength();
     } else {
diff --git a/core/fpdfapi/parser/fpdf_parser_utility.cpp b/core/fpdfapi/parser/fpdf_parser_utility.cpp
index 0cd4ca9225..7025b3e7d8 100644
--- a/core/fpdfapi/parser/fpdf_parser_utility.cpp
+++ b/core/fpdfapi/parser/fpdf_parser_utility.cpp
@@ -89,7 +89,7 @@ int32_t GetDirectInteger(CPDF_Dictionary* pDict, const CFX_ByteString& key) {
 }
 
 CFX_ByteString PDF_NameDecode(const CFX_ByteStringC& bstr) {
-  if (bstr.Find('#') == -1)
+  if (bstr.Find('#') == FX_STRNPOS)
     return CFX_ByteString(bstr);
 
   int size = bstr.GetLength();
@@ -110,7 +110,7 @@ CFX_ByteString PDF_NameDecode(const CFX_ByteStringC& bstr) {
 }
 
 CFX_ByteString PDF_NameDecode(const CFX_ByteString& orig) {
-  if (orig.Find('#') == -1)
+  if (orig.Find('#') == FX_STRNPOS)
     return orig;
   return PDF_NameDecode(orig.AsStringC());
 }