SkVarAlloc::approxBytesAllocated

src/core/SkVarAlloc.cpp

 #include "SkVarAlloc.h"
 
 // We use non-standard malloc diagnostic methods to make sure our allocations are sized well.
 #if defined(SK_BUILD_FOR_MAC)
     #include <malloc/malloc.h>
-#elif defined(SK_BUILD_FOR_LINUX)
+#elif defined(SK_BUILD_FOR_UNIX) || defined(SK_BUILD_FOR_WIN32)
     #include <malloc.h>
 #endif
 
 enum {
     kMinLgSize =  4,  // The smallest block we'd ever want to allocate is 16B,
     kMaxLgSize = 16,  // and we see no benefit allocating blocks larger than 64K.
 };
 
 struct SkVarAlloc::Block {
     Block* prev;
@@ skipping 32 matching lines @@
     fBlock = Block::Alloc(fBlock, alloc, flags);
     fByte = fBlock->data();
     fRemaining = alloc - sizeof(Block);
 
     if (fLgSize < kMaxLgSize) {
         fLgSize++;
     }
 
 #if defined(SK_BUILD_FOR_MAC)
     SkASSERT(alloc == malloc_good_size(alloc));
-#elif defined(SK_BUILD_FOR_LINUX)
-    SkASSERT(alloc == malloc_usable_size(fByte - sizeof(Block)));
+#elif defined(SK_BUILD_FOR_UNIX)
+    // TODO(mtklein): tune so we can assert something like this
+    //SkASSERT(alloc == malloc_usable_size(fBlock));
 #endif
 }
+
+static size_t heap_size(void* p) {
+#if defined(SK_BUILD_FOR_MAC)
+    return malloc_size(p);
+#elif defined(SK_BUILD_FOR_UNIX)
+    return malloc_usable_size(p);
+#elif defined(SK_BUILD_FOR_WIN32)
+    return _msize(p);
+#else
+    return 0;  // Tough luck.
+#endif
+}
+
+size_t SkVarAlloc::approxBytesAllocated() const {
+    size_t sum = 0;
+    for (Block* b = fBlock; b; b = b->prev) {
+        sum += heap_size(b);
+    }
+    return sum;
+}