Create TimeBase for time related classes.

src/base/bits.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/bits.h"
 
 #include <limits>
 
 #include "src/base/logging.h"
+#include "src/base/safe_math.h"
 
 namespace v8 {
 namespace base {
 namespace bits {
 
 uint32_t RoundUpToPowerOfTwo32(uint32_t value) {
   DCHECK_LE(value, 0x80000000u);
   value = value - 1;
   value = value | (value >> 1);
   value = value | (value >> 2);
@@ skipping 21 matching lines @@
   if (rhs == -1) return -lhs;
   return lhs / rhs;
 }
 
 
 int32_t SignedMod32(int32_t lhs, int32_t rhs) {
   if (rhs == 0 || rhs == -1) return 0;
   return lhs % rhs;
 }
 
+
+int64_t FromCheckedNumeric(const internal::CheckedNumeric<int64_t> value) {
+  if (value.IsValid())
+    return value.ValueUnsafe();
+
+  // We could return max/min but we don't really expose what the maximum delta
+  // is. Instead, return max/(-max), which is something that clients can reason
+  // about.
+  // TODO(rvargas) crbug.com/332611: don't use internal values.
+  int64_t limit = std::numeric_limits<int64_t>::max();
+  if (value.validity() == internal::RANGE_UNDERFLOW)
+    limit = -limit;
+  return value.ValueOrDefault(limit);
+}
+
+
+int64_t SignedSaturatedAdd64(int64_t lhs, int64_t rhs) {
+  internal::CheckedNumeric<int64_t> rv(lhs);
+  rv += rhs;
+  return FromCheckedNumeric(rv);
+}
+
+
+int64_t SignedSaturatedSub64(int64_t lhs, int64_t rhs) {
+  internal::CheckedNumeric<int64_t> rv(lhs);
+  rv -= rhs;
+  return FromCheckedNumeric(rv);
+}
+
 }  // namespace bits
 }  // namespace base
 }  // namespace v8