47 lines
1.8 KiB
C++
47 lines
1.8 KiB
C++
|
// 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.
|
||
|
|
//
|
||
|
|
// The purpose of this file is to supply the macro definintions necessary
|
||
|
|
// to make third_party/dmg_fp/dtoa.cc threadsafe.
|
||
|
|
#include "base/lazy_instance.h"
|
||
|
|
#include "base/logging.h"
|
||
|
|
#include "base/synchronization/lock.h"
|
||
|
|
|
||
|
|
// We need two locks because they're sometimes grabbed at the same time.
|
||
|
|
// A single lock would lead to an attempted recursive grab.
|
||
|
|
static base::LazyInstance<base::Lock>::Leaky
|
||
|
|
dtoa_lock_0 = LAZY_INSTANCE_INITIALIZER;
|
||
|
|
static base::LazyInstance<base::Lock>::Leaky
|
||
|
|
dtoa_lock_1 = LAZY_INSTANCE_INITIALIZER;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This define and the code below is to trigger thread-safe behavior
|
||
|
|
* in dtoa.cc, per this comment from the file:
|
||
|
|
*
|
||
|
|
* #define MULTIPLE_THREADS if the system offers preemptively scheduled
|
||
|
|
* multiple threads. In this case, you must provide (or suitably
|
||
|
|
* #define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed
|
||
|
|
* by FREE_DTOA_LOCK(n) for n = 0 or 1. (The second lock, accessed
|
||
|
|
* in pow5mult, ensures lazy evaluation of only one copy of high
|
||
|
|
* powers of 5; omitting this lock would introduce a small
|
||
|
|
* probability of wasting memory, but would otherwise be harmless.)
|
||
|
|
* You must also invoke freedtoa(s) to free the value s returned by
|
||
|
|
* dtoa. You may do so whether or not MULTIPLE_THREADS is #defined.
|
||
|
|
*/
|
||
|
|
#define MULTIPLE_THREADS
|
||
|
|
|
||
|
|
inline static void ACQUIRE_DTOA_LOCK(size_t n) {
|
||
|
|
DCHECK(n < 2);
|
||
|
|
base::Lock* lock = n == 0 ? dtoa_lock_0.Pointer() : dtoa_lock_1.Pointer();
|
||
|
|
lock->Acquire();
|
||
|
|
}
|
||
|
|
|
||
|
|
inline static void FREE_DTOA_LOCK(size_t n) {
|
||
|
|
DCHECK(n < 2);
|
||
|
|
base::Lock* lock = n == 0 ? dtoa_lock_0.Pointer() : dtoa_lock_1.Pointer();
|
||
|
|
lock->Release();
|
||
|
|
}
|
||
|
|
|
||
|
|
#include "base/third_party/dmg_fp/dtoa.cc"
|