Convert FX_STRSIZE int->size_t

Change the underlying type for FX_STRSIZE to size_t from int. This
will make the value unsigned and thus all values in the range of the
type will be valid. This allows for the final remove of negative
length strings, but also introduces a some casting and functional 
errors, since many parts of the code base assume that FX_STRSIZE is 
int or another signed type. This also CL fixes these errors.

BUG=pdfium:828

Change-Id: I231dca59e96fc9330cbb099eecbdfc41fcf86f5b
Reviewed-on: https://pdfium-review.googlesource.com/11830
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>

1 files changed, 2 insertions, 8 deletions

diff --git a/core/fxcrt/cfx_bytestring.h b/core/fxcrt/cfx_bytestring.h
index 261060bda0..432f28a06d 100644
--- a/core/fxcrt/cfx_bytestring.h
+++ b/core/fxcrt/cfx_bytestring.h
@@ -82,14 +82,8 @@ class CFX_ByteString {
     return m_pData ? FXSYS_strlen(m_pData->m_String) : 0;
   }
   bool IsEmpty() const { return !GetLength(); }
-
-  bool IsValidIndex(FX_STRSIZE index) const {
-    return 0 <= index && index < GetLength();
-  }
-
-  bool IsValidLength(FX_STRSIZE length) const {
-    return 0 <= length && length <= GetLength();
-  }
+  bool IsValidIndex(FX_STRSIZE index) const { return index < GetLength(); }
+  bool IsValidLength(FX_STRSIZE length) const { return length <= GetLength(); }
 
   int Compare(const CFX_ByteStringC& str) const;
   bool EqualNoCase(const CFX_ByteStringC& str) const;