1 files changed, 49 insertions, 0 deletions
diff --git a/gfx/skia/skia/include/private/base/SkSafe32.h b/gfx/skia/skia/include/private/base/SkSafe32.h
new file mode 100644
index 0000000000..5ba4c2f9a4
--- /dev/null
+++ b/gfx/skia/skia/include/private/base/SkSafe32.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSafe32_DEFINED
+#define SkSafe32_DEFINED
+
+#include "include/private/base/SkAssert.h"
+#include "include/private/base/SkMath.h"
+
+#include <cstdint>
+
+static constexpr int32_t Sk64_pin_to_s32(int64_t x) {
+    return x < SK_MinS32 ? SK_MinS32 : (x > SK_MaxS32 ? SK_MaxS32 : (int32_t)x);
+}
+
+static constexpr int32_t Sk32_sat_add(int32_t a, int32_t b) {
+    return Sk64_pin_to_s32((int64_t)a + (int64_t)b);
+}
+
+static constexpr int32_t Sk32_sat_sub(int32_t a, int32_t b) {
+    return Sk64_pin_to_s32((int64_t)a - (int64_t)b);
+}
+
+// To avoid UBSAN complaints about 2's compliment overflows
+//
+static constexpr int32_t Sk32_can_overflow_add(int32_t a, int32_t b) {
+    return (int32_t)((uint32_t)a + (uint32_t)b);
+}
+static constexpr int32_t Sk32_can_overflow_sub(int32_t a, int32_t b) {
+    return (int32_t)((uint32_t)a - (uint32_t)b);
+}
+
+/**
+ * This is a 'safe' abs for 32-bit integers that asserts when undefined behavior would occur.
+ * SkTAbs (in SkTemplates.h) is a general purpose absolute-value function.
+ */
+static inline int32_t SkAbs32(int32_t value) {
+    SkASSERT(value != SK_NaN32);  // The most negative int32_t can't be negated.
+    if (value < 0) {
+        value = -value;
+    }
+    return value;
+}
+
+#endif