add helper to check for overflow

pre-CL to aid in changing the convention for when we overflow

Bug: skia:
Change-Id: I1e34a18fefb80187787a1c0c8ed7ee3516744d24
Reviewed-on: https://skia-review.googlesource.com/57103
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

3 files changed, 4 insertions, 4 deletions

diff --git a/src/core/SkAutoPixmapStorage.cpp b/src/core/SkAutoPixmapStorage.cpp
index df0c0fa878..47f41e7b92 100644
--- a/src/core/SkAutoPixmapStorage.cpp
+++ b/src/core/SkAutoPixmapStorage.cpp
@@ -37,7 +37,7 @@ bool SkAutoPixmapStorage::tryAlloc(const SkImageInfo& info) {
 
     size_t rb;
     size_t size = AllocSize(info, &rb);
-    if (0 == size) {
+    if (SkImageInfo::ByteSizeOverflowed(size)) {
         return false;
     }
     void* pixels = sk_malloc_flags(size, 0);
diff --git a/src/core/SkBitmapCache.cpp b/src/core/SkBitmapCache.cpp
index 8d3991a9d5..0fc0c9e075 100644
--- a/src/core/SkBitmapCache.cpp
+++ b/src/core/SkBitmapCache.cpp
@@ -290,7 +290,7 @@ SkBitmapCache::RecPtr SkBitmapCache::Alloc(const SkBitmapCacheDesc& desc, const
 
     const size_t rb = info.minRowBytes();
     size_t size = info.computeByteSize(rb);
-    if (0 == size) {
+    if (SkImageInfo::ByteSizeOverflowed(size)) {
         return nullptr;
     }
 
diff --git a/src/core/SkMallocPixelRef.cpp b/src/core/SkMallocPixelRef.cpp
index 10861028b1..4a34d39170 100644
--- a/src/core/SkMallocPixelRef.cpp
+++ b/src/core/SkMallocPixelRef.cpp
@@ -80,8 +80,8 @@ sk_sp<SkPixelRef> SkMallocPixelRef::MakeUsing(void*(*allocProc)(size_t),
     size_t size = 0;
     if (!info.isEmpty() && rowBytes) {
         size = info.computeByteSize(rowBytes);
-        if (!size) {
-            return nullptr; // overflow
+        if (SkImageInfo::ByteSizeOverflowed(size)) {
+            return nullptr;
         }
     }
 #endif