Just add new safe size apis

Update skia (and then hide the older versions) to come later
Inspired by https://skia-review.googlesource.com/c/skia/+/52665

Bug: skia:
Change-Id: I15c7395557fb49c4163cb3b323b5428abd2c752d
Reviewed-on: https://skia-review.googlesource.com/53520
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/core/SkImageInfo.cpp b/src/core/SkImageInfo.cpp
index 1baf0b77de..c610b82bdc 100644
--- a/src/core/SkImageInfo.cpp
+++ b/src/core/SkImageInfo.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "SkImageInfo.h"
+#include "SkSafeMath.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 
@@ -70,6 +71,16 @@ static SkColorType stored_to_live(unsigned stored) {
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
+size_t SkImageInfo::computeByteSize(size_t rowBytes) const {
+    if (0 == fHeight) {
+        return 0;
+    }
+    SkSafeMath safe;
+    size_t bytes = safe.add(safe.mul(fHeight - 1, rowBytes),
+                            safe.mul(fWidth, this->bytesPerPixel()));
+    return safe ? bytes : 0;
+}
+
 static bool alpha_type_is_valid(SkAlphaType alphaType) {
     return (alphaType >= kUnknown_SkAlphaType) && (alphaType <= kLastEnum_SkAlphaType);
 }