add realloc method to SkAutoSTMalloc

include/core/SkTemplates.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkTemplates_DEFINED
@@ skipping 446 matching lines @@
     }
 
     T& operator[](int index) {
         return fPtr[index];
     }
 
     const T& operator[](int index) const {
         return fPtr[index];
     }
 
+    // Reallocs the array, can be used to shrink the allocation.  By reset above, we know fPtr's
+    // size is > N so the below memcpys are safe
+    void realloc(size_t count) {
+        if (count > N) {
+            if (fPtr == fTStorage) {
+                fPtr = (T*)sk_malloc_flags(count * sizeof(T), SK_MALLOC_THROW | SK_MALLOC_TEMP);

[mtklein, 2015/04/07 19:27:33]

Let's use sk_malloc_throw.  I don't believe SK_MALLOC_TEMP does anything, but if
it did this sure wouldn't be the place to use it.

+                memcpy(fPtr, fTStorage, N);
+            } else {
+                fPtr = (T*)sk_realloc_throw(fPtr, count * sizeof(T));
+            }
+        } else if (fPtr != fTStorage) {
+            memcpy(fTStorage, fPtr, N);

[mtklein, 2015/04/07 19:27:34]

Do you ever really hit this case that you shrink back into the static storage? 
If not, let's not bother?

+            SkDELETE(fPtr);
+            fPtr = fTStorage;
+        }
+    }
+
 private:
     T*          fPtr;
     union {
         uint32_t    fStorage32[(N*sizeof(T) + 3) >> 2];
         T           fTStorage[1];   // do NOT want to invoke T::T()
     };
 };
 
 /**
  * Reserves memory that is aligned on double and pointer boundaries.
@@ skipping 22 matching lines @@
     /**
      * Returns void* because this object does not initialize the
      * memory. Use placement new for types that require a cons.
      */
     void* get() { return fStorage.get(); }
 private:
     SkAlignedSStorage<sizeof(T)*N> fStorage;
 };
 
 #endif