Sanity check the values of TRUE and FALSE.

core/include/fxge/fx_dib.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_INCLUDE_FXGE_FX_DIB_H_
 #define CORE_INCLUDE_FXGE_FX_DIB_H_
 
 #include "../fxcrt/fx_basic.h"
@@ skipping 178 matching lines @@
                                   int dest_bpp,
                                   int dest_width,
                                   FX_BOOL bFlipX,
                                   int clip_left,
                                   int clip_width) const = 0;
 
   virtual void SetDownSampleSize(int width, int height) const {}
 
   int GetBPP() const { return m_bpp; }
 
   FX_BOOL IsAlphaMask() const { return m_AlphaFlag == 1; }

[Tom Sepez, 2015/10/15 17:08:31]

This one feels wrong.  If its a mask, all bits should be independent.  Can you
look into this? Or at least write a comment about if the value is 1, then its
one thing, otherwise its a bitmask.

[Lei Zhang, 2015/10/19 08:56:18]

I looked at this briefly and added comments. With our current test repo, we only
ever see values of 0-2, though 4 should be possible with a test case.

 
-  FX_BOOL HasAlpha() const { return m_AlphaFlag & 2 ? TRUE : FALSE; }
+  FX_BOOL HasAlpha() const { return m_AlphaFlag & 2; }

[Tom Sepez, 2015/10/15 17:08:31]

Actually, what you want is { return !!(m_AlphaFlag & 2); } to force 0/1-ness. 
The !! idiom is well-known so we can use it without elaboration.

[Lei Zhang, 2015/10/19 08:56:18]

Done.

 
   FX_BOOL IsOpaqueImage() const { return !(m_AlphaFlag & 3); }
 
-  FX_BOOL IsCmykImage() const { return m_AlphaFlag & 4 ? TRUE : FALSE; }
+  FX_BOOL IsCmykImage() const { return m_AlphaFlag & 4; }
 
   int GetPaletteSize() const {
     return IsAlphaMask() ? 0 : (m_bpp == 1 ? 2 : (m_bpp == 8 ? 256 : 0));
   }
 
   FX_DWORD GetPaletteEntry(int index) const;
 
   void SetPaletteEntry(int index, FX_DWORD color);
   FX_DWORD GetPaletteArgb(int index) const { return GetPaletteEntry(index); }
   void SetPaletteArgb(int index, FX_DWORD color) {
@@ skipping 469 matching lines @@
   int m_Status;
   FX_RECT m_ClipBox;
   FX_DWORD m_Flags;
   int m_AlphaFlag;
   void* m_pIccTransform;
   FX_BOOL m_bRgbByteOrder;
   int m_BlendType;
 };
 
 #endif  // CORE_INCLUDE_FXGE_FX_DIB_H_