Creating functions for uploading a mipmapped texture.

src/core/SkMipMap.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkMipMap_DEFINED
 #define SkMipMap_DEFINED
 
 #include "SkCachedData.h"
 #include "SkScalar.h"
+#include "SkMipMapLevel.h"
 
 class SkBitmap;
-class SkDiscardableMemory;
-
-typedef SkDiscardableMemory* (*SkDiscardableFactoryProc)(size_t bytes);
 
 class SkMipMap : public SkCachedData {
 public:
     static SkMipMap* Build(const SkBitmap& src, SkDiscardableFactoryProc);
 
     struct Level {
         void*       fPixels;
         uint32_t    fRowBytes;
         uint32_t    fWidth, fHeight;
         float       fScale; // < 1.0
     };
 
     bool extractLevel(SkScalar scale, Level*) const;
+    int getLevelsCount() const;
+    // getLevel() is 1-indexed because the SkMipMap contains the generated
+    // mipmaps, which does not include the base level (which is normally
+    // mipmap level 0). SkMipMap contains mipmap levels 1-x, not 0-x.
+    bool getLevel(int levelIndex, Level* levelPtr) const;
 
 protected:
     void onDataChange(void* oldData, void* newData) override {
         fLevels = (Level*)newData; // could be nullptr
     }
 
 private:
     Level*  fLevels;
     int     fCount;
 
     // we take ownership of levels, and will free it with sk_free()
     SkMipMap(void* malloc, size_t size) : INHERITED(malloc, size) {}
     SkMipMap(size_t size, SkDiscardableMemory* dm) : INHERITED(size, dm) {}
 
     static size_t AllocLevelsSize(int levelCount, size_t pixelSize);
 
     typedef SkCachedData INHERITED;
 };
 
 #endif