Chromium -> Mojo roll.

gpu/command_buffer/common/gles2_cmd_utils.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is here so other GLES2 related files can have a common set of
 // includes where appropriate.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 #define GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 
 #include <stdint.h>
 
 #include <limits>
 #include <string>
 #include <vector>
 
+#include "base/numerics/safe_math.h"
 #include "gpu/command_buffer/common/gles2_utils_export.h"
 
 namespace gpu {
 namespace gles2 {
 
 // Does a multiply and checks for overflow.  If the multiply did not overflow
 // returns true.
 
 // Multiplies 2 32 bit unsigned numbers checking for overflow.
 // If there was no overflow returns true.
 inline bool SafeMultiplyUint32(uint32_t a, uint32_t b, uint32_t* dst) {
-  if (b == 0) {
-    *dst = 0;
-    return true;
-  }
-  uint32_t v = a * b;
-  if (v / b != a) {
-    *dst = 0;
-    return false;
-  }
-  *dst = v;
-  return true;
+  DCHECK(dst);
+  base::CheckedNumeric<uint32_t> checked = a;
+  checked *= b;
+  *dst = checked.ValueOrDefault(0);
+  return checked.IsValid();
 }
 
 // Does an add checking for overflow.  If there was no overflow returns true.
 inline bool SafeAddUint32(uint32_t a, uint32_t b, uint32_t* dst) {
-  if (a + b < a) {
-    *dst = 0;
-    return false;
-  }
-  *dst = a + b;
-  return true;
+  DCHECK(dst);
+  base::CheckedNumeric<uint32_t> checked = a;
+  checked += b;
+  *dst = checked.ValueOrDefault(0);
+  return checked.IsValid();
 }
 
 // Does an add checking for overflow.  If there was no overflow returns true.
 inline bool SafeAddInt32(int32_t a, int32_t b, int32_t* dst) {
-  int64_t sum64 = static_cast<int64_t>(a) + b;
-  int32_t sum32 = static_cast<int32_t>(sum64);
-  bool safe = sum64 == static_cast<int64_t>(sum32);
-  *dst = safe ? sum32 : 0;
-  return safe;
-}
-
-// Return false if |value| is more than a 32 bit integer can represent.
-template<typename T>
-inline bool FitInt32NonNegative(T value) {
-  const int32_t max = std::numeric_limits<int32_t>::max();
-  return (std::numeric_limits<T>::max() <= max ||
-          value <= static_cast<T>(max));
+  DCHECK(dst);
+  base::CheckedNumeric<int32_t> checked = a;
+  checked += b;
+  *dst = checked.ValueOrDefault(0);
+  return checked.IsValid();
 }
 
 // Utilties for GLES2 support.
 class GLES2_UTILS_EXPORT GLES2Util {
  public:
   static const int kNumFaces = 6;
 
   // Bits returned by GetChannelsForFormat
   enum ChannelBits {
     kRed = 0x1,
@@ skipping 150 matching lines @@
   bool fail_if_major_perf_caveat;
   bool lose_context_when_out_of_memory;
   bool es3_context_required;
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_