1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 // 5 // The purpose of this file is to supply the macro definintions necessary 6 // to make third_party/dmg_fp/dtoa.cc threadsafe. 7 #include "base/synchronization/lock.h" 8 #include "base/logging.h" 9 10 // We need two locks because they're sometimes grabbed at the same time. 11 // A single lock would lead to an attempted recursive grab. 12 static base::Lock dtoa_locks[2]; 13 14 /* 15 * This define and the code below is to trigger thread-safe behavior 16 * in dtoa.cc, per this comment from the file: 17 * 18 * #define MULTIPLE_THREADS if the system offers preemptively scheduled 19 * multiple threads. In this case, you must provide (or suitably 20 * #define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed 21 * by FREE_DTOA_LOCK(n) for n = 0 or 1. (The second lock, accessed 22 * in pow5mult, ensures lazy evaluation of only one copy of high 23 * powers of 5; omitting this lock would introduce a small 24 * probability of wasting memory, but would otherwise be harmless.) 25 * You must also invoke freedtoa(s) to free the value s returned by 26 * dtoa. You may do so whether or not MULTIPLE_THREADS is #defined. 27 */ 28 #define MULTIPLE_THREADS 29 30 inline static void ACQUIRE_DTOA_LOCK(size_t n) { 31 DCHECK(n < arraysize(dtoa_locks)); 32 dtoa_locks[n].Acquire(); 33 } 34 35 inline static void FREE_DTOA_LOCK(size_t n) { 36 DCHECK(n < arraysize(dtoa_locks)); 37 dtoa_locks[n].Release(); 38 } 39 40 #include "base/third_party/dmg_fp/dtoa.cc" 41
