Current File : /home/vacivi36/vittasync.vacivitta.com.br/vittasync/node/deps/v8/src/heap/index-generator.cc
// Copyright 2020 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/heap/index-generator.h"
namespace v8 {
namespace internal {
IndexGenerator::IndexGenerator(size_t size) : first_use_(size > 0) {
if (size == 0) return;
base::MutexGuard guard(&lock_);
ranges_to_split_.emplace(0, size);
}
base::Optional<size_t> IndexGenerator::GetNext() {
base::MutexGuard guard(&lock_);
if (first_use_) {
first_use_ = false;
return 0;
}
if (ranges_to_split_.empty()) return base::nullopt;
// Split the oldest running range in 2 and return the middle index as
// starting point.
auto range = ranges_to_split_.front();
ranges_to_split_.pop();
size_t size = range.second - range.first;
size_t mid = range.first + size / 2;
// Both sides of the range are added to |ranges_to_split_| so they may be
// further split if possible.
if (mid - range.first > 1) ranges_to_split_.emplace(range.first, mid);
if (range.second - mid > 1) ranges_to_split_.emplace(mid, range.second);
return mid;
}
} // namespace internal
} // namespace v8
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