Make is_ktx safer

third_party/ktx/ktx.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkKTXFile_DEFINED
 #define SkKTXFile_DEFINED
@@ skipping 16 matching lines @@
 // texture in an OpenGL application, including the use of compressed data.
 //
 // A full format specification can be found here:
 // http://www.khronos.org/opengles/sdk/tools/KTX/file_format_spec/
 
 class SkKTXFile {
 public:
     // The ownership of the data remains with the caller. This class is intended
     // to be used as a logical wrapper around the data in order to properly
     // access the pixels.
-    SkKTXFile(SkData* data)
-        : fData(data), fSwapBytes(false)
-    {
+    SkKTXFile(SkData* data) : fData(data), fSwapBytes(false) {
         data->ref();
         fValid = this->readKTXFile(fData->bytes(), fData->size());
     }
 
     bool valid() const { return fValid; }
 
     int width() const { return static_cast<int>(fHeader.fPixelWidth); }
     int height() const { return static_cast<int>(fHeader.fPixelHeight); }
 
     const uint8_t *pixelData(int mipmap = 0) const {
         SkASSERT(!this->valid() || mipmap < fPixelData.count());
         return this->valid() ? fPixelData[mipmap].data() : NULL;
     }
 
     // If the decoded KTX file has the following key, then it will
     // return the associated value. If not found, the empty string
     // is returned.
     SkString getValueForKey(const SkString& key) const;
 
     int numMipmaps() const { return static_cast<int>(fHeader.fNumberOfMipmapLevels); }
 
     bool isCompressedFormat(SkTextureCompressor::Format fmt) const;
     bool isRGBA8() const;
     bool isRGB8() const;
 
-    static bool is_ktx(const uint8_t *data);
+    static bool is_ktx(const uint8_t data[], size_t size);
     static bool is_ktx(SkStreamRewindable* stream);
 
     static bool WriteETC1ToKTX(SkWStream* stream, const uint8_t *etc1Data,
                                uint32_t width, uint32_t height);
     static bool WriteBitmapToKTX(SkWStream* stream, const SkBitmap& bitmap);
 private:
 
     // The blob holding the file data.
     SkAutoTUnref<SkData> fData;
 
@@ skipping 59 matching lines @@
     // If the endianness of the platform is different than the file,
     // then we need to do proper byte swapping.
     bool fSwapBytes;
 
     // Read an integer from a buffer, advance the buffer, and swap
     // bytes if fSwapBytes is set
     uint32_t readInt(const uint8_t** buf, size_t* bytesLeft) const;
 };
 
 #endif  // SkKTXFile_DEFINED