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diff --git a/src/zstd/contrib/pzstd/utils/ThreadPool.h b/src/zstd/contrib/pzstd/utils/ThreadPool.h
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+/*
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ */
+#pragma once
+
+#include "utils/WorkQueue.h"
+
+#include <cstddef>
+#include <functional>
+#include <thread>
+#include <vector>
+
+namespace pzstd {
+/// A simple thread pool that pulls tasks off its queue in FIFO order.
+class ThreadPool {
+ std::vector<std::thread> threads_;
+
+ WorkQueue<std::function<void()>> tasks_;
+
+ public:
+ /// Constructs a thread pool with `numThreads` threads.
+ explicit ThreadPool(std::size_t numThreads) {
+ threads_.reserve(numThreads);
+ for (std::size_t i = 0; i < numThreads; ++i) {
+ threads_.emplace_back([this] {
+ std::function<void()> task;
+ while (tasks_.pop(task)) {
+ task();
+ }
+ });
+ }
+ }
+
+ /// Finishes all tasks currently in the queue.
+ ~ThreadPool() {
+ tasks_.finish();
+ for (auto& thread : threads_) {
+ thread.join();
+ }
+ }
+
+ /**
+ * Adds `task` to the queue of tasks to execute. Since `task` is a
+ * `std::function<>`, it cannot be a move only type. So any lambda passed must
+ * not capture move only types (like `std::unique_ptr`).
+ *
+ * @param task The task to execute.
+ */
+ void add(std::function<void()> task) {
+ tasks_.push(std::move(task));
+ }
+};
+}