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49 lines
1.8 KiB
C++
49 lines
1.8 KiB
C++
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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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//
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// The purpose of this file is to supply the macro definintions necessary
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// to make third_party/dmg_fp/dtoa.cc threadsafe.
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#include "base/lazy_instance.h"
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#include "base/logging.h"
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#include "base/synchronization/lock.h"
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// We need two locks because they're sometimes grabbed at the same time.
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// A single lock would lead to an attempted recursive grab.
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static base::LazyInstance<base::Lock>::Leaky
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dtoa_lock_0 = LAZY_INSTANCE_INITIALIZER;
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static base::LazyInstance<base::Lock>::Leaky
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dtoa_lock_1 = LAZY_INSTANCE_INITIALIZER;
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/*
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* This define and the code below is to trigger thread-safe behavior
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* in dtoa.cc, per this comment from the file:
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*
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* #define MULTIPLE_THREADS if the system offers preemptively scheduled
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* multiple threads. In this case, you must provide (or suitably
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* #define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed
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* by FREE_DTOA_LOCK(n) for n = 0 or 1. (The second lock, accessed
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* in pow5mult, ensures lazy evaluation of only one copy of high
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* powers of 5; omitting this lock would introduce a small
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* probability of wasting memory, but would otherwise be harmless.)
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* You must also invoke freedtoa(s) to free the value s returned by
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* dtoa. You may do so whether or not MULTIPLE_THREADS is #defined.
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*/
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#define MULTIPLE_THREADS
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inline static void ACQUIRE_DTOA_LOCK(size_t n) {
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DCHECK(n < 2);
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base::Lock* lock = n == 0 ? dtoa_lock_0.Pointer() : dtoa_lock_1.Pointer();
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lock->Acquire();
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}
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inline static void FREE_DTOA_LOCK(size_t n) {
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DCHECK(n < 2);
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base::Lock* lock = n == 0 ? dtoa_lock_0.Pointer() : dtoa_lock_1.Pointer();
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lock->Release();
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}
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#include "base/third_party/dmg_fp/dtoa.cc"
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#undef Long // To avoid breaking jni code in jumbo builds
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