Fix errors caused by unsafe conversions to/from size_t

third_party/WebKit/Source/platform/image-decoders/png/PNGImageDecoder.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
  *
  * Portions are Copyright (C) 2001 mozilla.org
  *
  * Other contributors:
  *   Stuart Parmenter <stuart@mozilla.com>
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 69 matching lines @@
 }
 
 } // anonymous
 
 namespace blink {
 
 class PNGImageReader final {
     USING_FAST_MALLOC(PNGImageReader);
     WTF_MAKE_NONCOPYABLE(PNGImageReader);
 public:
-    PNGImageReader(PNGImageDecoder* decoder, unsigned readOffset)
+    PNGImageReader(PNGImageDecoder* decoder, size_t readOffset)
         : m_decoder(decoder)
         , m_readOffset(readOffset)
         , m_currentBufferSize(0)
         , m_decodingSizeOnly(false)
         , m_hasAlpha(false)
 #if USE(QCMSLIB)
         , m_transform(0)
         , m_rowBuffer()
 #endif
     {
@@ skipping 15 matching lines @@
 
     bool decode(const SharedBuffer& data, bool sizeOnly)
     {
         m_decodingSizeOnly = sizeOnly;
 
         // We need to do the setjmp here. Otherwise bad things will happen.
         if (setjmp(JMPBUF(m_png)))
             return m_decoder->setFailed();
 
         const char* segment;
-        while (unsigned segmentLength = data.getSomeData(segment, m_readOffset)) {
+        while (size_t segmentLength = data.getSomeData(segment, m_readOffset)) {
             m_readOffset += segmentLength;
             m_currentBufferSize = m_readOffset;
             png_process_data(m_png, m_info, reinterpret_cast<png_bytep>(const_cast<char*>(segment)), segmentLength);
             if (sizeOnly ? m_decoder->isDecodedSizeAvailable() : m_decoder->frameIsCompleteAtIndex(0))
                 return true;
         }
 
         return false;
     }
 
     png_structp pngPtr() const { return m_png; }
     png_infop infoPtr() const { return m_info; }
 
-    void setReadOffset(unsigned offset) { m_readOffset = offset; }
-    unsigned currentBufferSize() const { return m_currentBufferSize; }
+    void setReadOffset(size_t offset) { m_readOffset = offset; }
+    size_t currentBufferSize() const { return m_currentBufferSize; }
     bool decodingSizeOnly() const { return m_decodingSizeOnly; }
     void setHasAlpha(bool hasAlpha) { m_hasAlpha = hasAlpha; }
     bool hasAlpha() const { return m_hasAlpha; }
 
     png_bytep interlaceBuffer() const { return m_interlaceBuffer.get(); }
     void createInterlaceBuffer(int size) { m_interlaceBuffer = adoptArrayPtr(new png_byte[size]); }
 #if USE(QCMSLIB)
     png_bytep rowBuffer() const { return m_rowBuffer.get(); }
     void createRowBuffer(int size) { m_rowBuffer = adoptArrayPtr(new png_byte[size]); }
     qcms_transform* colorTransform() const { return m_transform; }
@@ skipping 35 matching lines @@
         m_transform = qcms_transform_create(inputProfile, dataFormat, deviceProfile, dataFormat, QCMS_INTENT_PERCEPTUAL);
 
         qcms_profile_release(inputProfile);
     }
 #endif
 
 private:
     png_structp m_png;
     png_infop m_info;
     PNGImageDecoder* m_decoder;
-    unsigned m_readOffset;
-    unsigned m_currentBufferSize;
+    size_t m_readOffset;
+    size_t m_currentBufferSize;
     bool m_decodingSizeOnly;
     bool m_hasAlpha;
     OwnPtr<png_byte[]> m_interlaceBuffer;
 #if USE(QCMSLIB)
     qcms_transform* m_transform;
     OwnPtr<png_byte[]> m_rowBuffer;
 #endif
 };
 
-PNGImageDecoder::PNGImageDecoder(AlphaOption alphaOption, GammaAndColorProfileOption colorOptions, size_t maxDecodedBytes, unsigned offset)
+PNGImageDecoder::PNGImageDecoder(AlphaOption alphaOption, GammaAndColorProfileOption colorOptions, size_t maxDecodedBytes, size_t offset)
     : ImageDecoder(alphaOption, colorOptions, maxDecodedBytes)
     , m_hasColorProfile(false)
     , m_offset(offset)
 {
 }
 
 PNGImageDecoder::~PNGImageDecoder()
 {
 }
 
@@ skipping 284 matching lines @@
     // has failed.
     if (!m_reader->decode(*m_data, onlySize) && isAllDataReceived())
         setFailed();
 
     // If decoding is done or failed, we don't need the PNGImageReader anymore.
     if (isComplete(this) || failed())
         m_reader.clear();
 }
 
 } // namespace blink