Make container classes in SkTemplates.h more consistent

include/private/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 191 matching lines @@
             if (count > kCount) {
                 const uint64_t size64 = sk_64_mul(count, sizeof(T));
                 const size_t size = static_cast<size_t>(size64);
                 if (size != size64) {
                     sk_out_of_memory();
                 }
                 fArray = (T*) sk_malloc_throw(size);
             } else if (count > 0) {
                 fArray = (T*) fStorage;
             } else {
+                SkASSERT(0 == count);

[bsalomon, 2016/06/23 17:53:34]

I think it'd be slightly clearer to just put SkASSERT(count >= 0); at the top of
the function.

[csmartdalton, 2016/06/23 18:07:26]

Done.

                 fArray = NULL;
             }
 
             fCount = count;
         }
 
         iter = fArray;
         T* stop = fArray + count;
         while (iter < stop) {
             new (iter++) T;
@@ skipping 38 matching lines @@
  */
 template <typename T> class SkAutoTMalloc : SkNoncopyable {
 public:
     /** Takes ownership of the ptr. The ptr must be a value which can be passed to sk_free. */
     explicit SkAutoTMalloc(T* ptr = NULL) {
         fPtr = ptr;
     }
 
     /** Allocates space for 'count' Ts. */
     explicit SkAutoTMalloc(size_t count) {
-        fPtr = (T*)sk_malloc_flags(count * sizeof(T), SK_MALLOC_THROW);
+        fPtr = count ? (T*)sk_malloc_flags(count * sizeof(T), SK_MALLOC_THROW) : nullptr;
     }
 
     ~SkAutoTMalloc() {
         sk_free(fPtr);
     }
 
     /** Resize the memory area pointed to by the current ptr preserving contents. */
     void realloc(size_t count) {
         fPtr = reinterpret_cast<T*>(sk_realloc_throw(fPtr, count * sizeof(T)));
     }
@@ skipping 38 matching lines @@
     T* fPtr;
 };
 
 template <size_t kCountRequested, typename T> class SkAutoSTMalloc : SkNoncopyable {
 public:
     SkAutoSTMalloc() : fPtr(fTStorage) {}
 
     SkAutoSTMalloc(size_t count) {
         if (count > kCount) {
             fPtr = (T*)sk_malloc_flags(count * sizeof(T), SK_MALLOC_THROW | SK_MALLOC_TEMP);
+        } else if (count) {
+            fPtr = fTStorage;
         } else {
-            fPtr = fTStorage;
+            fPtr = nullptr;
         }
     }
 
     ~SkAutoSTMalloc() {
         if (fPtr != fTStorage) {
             sk_free(fPtr);
         }
     }
 
     // doesn't preserve contents
     T* reset(size_t count) {
         if (fPtr != fTStorage) {
             sk_free(fPtr);
         }
         if (count > kCount) {
             fPtr = (T*)sk_malloc_throw(count * sizeof(T));
+        } else if (count) {
+            fPtr = fTStorage;
         } else {
-            fPtr = fTStorage;
+            fPtr = nullptr;
         }
         return fPtr;
     }
 
     T* get() const { return fPtr; }
 
     operator T*() {
         return fPtr;
     }
 
@@ skipping 111 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(); }
     const void* get() const { return fStorage.get(); }
 private:
     SkAlignedSStorage<sizeof(T)*N> fStorage;
 };
 
 #endif