Porting refactoring changes:...

base/rand_util.cc

+// Copyright (c) 2008 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.
+
+#include "base/rand_util.h"
+
+#include <math.h>
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+
+namespace {
+
+union uint64_splitter {
+  uint64 normal;
+  uint16 split[4];
+};
+
+}  // namespace
+
+namespace base {
+
+int RandInt(int min, int max) {
+  DCHECK(min <= max);
+
+  uint64 range = static_cast<int64>(max) - min + 1;
+  uint64 number = base::RandUInt64();
+  int result = min + number % range;

[Mark Mentovai, 2008/09/29 22:20:05]

This needed to be static_cast<int>(number % range) to placate MSVC, which warned
about the loss of precision.  This is safe, because range can never be >
UINT_MAX + 1, so number % range can never be > UINT_MAX.

+  DCHECK(result >= min && result <= max);
+  return result;
+}
+
+double RandDouble() {
+  uint64_splitter number;
+  number.normal = base::RandUInt64();
+
+  // Standard code based on drand48 would give only 48 bits of precision.
+  // We try to get maximum precision for IEEE 754 double (52 bits).
+  double result = ldexp(number.split[0] & 0xf, -52) +

[Mark Mentovai, 2008/09/29 22:20:05]

MSVC is strict about these too, because its C library overloads ldexp to accept
double, long double, and float arguments instead of requiring the caller to
choose between ldexp, ldexpl, and ldexpf.  (Actually, it provides the distinct
names too, but also makes the overloads available.)

Added static_cast<double> around the first parameter in each call here.

+                  ldexp(number.split[1], -48) +
+                  ldexp(number.split[2], -32) +
+                  ldexp(number.split[3], -16);
+  DCHECK(result >= 0.0 && result < 1.0);
+  return result;
+}
+
+}  // namespace base