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, 4 insertions, 12 deletions

diff --git a/core/fxcrt/cfx_string_c_template.h b/core/fxcrt/cfx_string_c_template.h
index 6bc71d853d..8585d73ae6 100644
--- a/core/fxcrt/cfx_string_c_template.h
+++ b/core/fxcrt/cfx_string_c_template.h
@@ -36,8 +36,7 @@ class CFX_StringCTemplate {
         m_Length(ptr ? FXSYS_len(ptr) : 0) {}
 
   CFX_StringCTemplate(const CharType* ptr, FX_STRSIZE len)
-      : m_Ptr(reinterpret_cast<const UnsignedType*>(ptr)),
-        m_Length(len < 0 ? FXSYS_len(ptr) : len) {}
+      : m_Ptr(reinterpret_cast<const UnsignedType*>(ptr)), m_Length(len) {}
 
   template <typename U = UnsignedType>
   CFX_StringCTemplate(
@@ -106,7 +105,7 @@ class CFX_StringCTemplate {
       return 0;
 
     uint32_t strid = 0;
-    FX_STRSIZE size = std::min(4, m_Length);
+    FX_STRSIZE size = std::min(static_cast<FX_STRSIZE>(4), m_Length);
     for (FX_STRSIZE i = 0; i < size; i++)
       strid = strid * 256 + m_Ptr.Get()[i];
 
@@ -119,16 +118,9 @@ class CFX_StringCTemplate {
   }
 
   FX_STRSIZE GetLength() const { return m_Length; }
-
   bool IsEmpty() const { return m_Length == 0; }
-
-  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(); }
 
   const UnsignedType& operator[](const FX_STRSIZE index) const {
     ASSERT(IsValidIndex(index));