Add PZstandard to contrib/

contrib/pzstd/utils/Buffer.h

@@ -0,0 +1,99 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#pragma once
+
+#include "utils/Range.h"
+
+#include <array>
+#include <cstddef>
+#include <memory>
+
+namespace pzstd {
+
+/**
+ * A `Buffer` has a pointer to a shared buffer, and a range of the buffer that
+ * it owns.
+ * The idea is that you can allocate one buffer, and write chunks into it
+ * and break off those chunks.
+ * The underlying buffer is reference counted, and will be destroyed when all
+ * `Buffer`s that reference it are destroyed.
+ */
+class Buffer {
+  std::shared_ptr<unsigned char> buffer_;
+  MutableByteRange range_;
+
+  static void delete_buffer(unsigned char* buffer) {
+    delete[] buffer;
+  }
+
+ public:
+  /// Construct an empty buffer that owns no data.
+  explicit Buffer() {}
+
+  /// Construct a `Buffer` that owns a new underlying buffer of size `size`.
+  explicit Buffer(std::size_t size)
+      : buffer_(new unsigned char[size], delete_buffer),
+        range_(buffer_.get(), buffer_.get() + size) {}
+
+  explicit Buffer(std::shared_ptr<unsigned char> buffer, MutableByteRange data)
+      : buffer_(buffer), range_(data) {}
+
+  Buffer(Buffer&&) = default;
+  Buffer& operator=(Buffer&&) & = default;
+
+  /**
+   * Splits the data into two pieces: [begin, begin + n), [begin + n, end).
+   * Their data both points into the same underlying buffer.
+   * Modifies the original `Buffer` to point to only [begin + n, end).
+   *
+   * @param n  The offset to split at.
+   * @returns  A buffer that owns the data [begin, begin + n).
+   */
+  Buffer splitAt(std::size_t n) {
+    auto firstPiece = range_.subpiece(0, n);
+    range_.advance(n);
+    return Buffer(buffer_, firstPiece);
+  }
+
+  /// Modifies the buffer to point to the range [begin + n, end).
+  void advance(std::size_t n) {
+    range_.advance(n);
+  }
+
+  /// Modifies the buffer to point to the range [begin, end - n).
+  void subtract(std::size_t n) {
+    range_.subtract(n);
+  }
+
+  /// Returns a read only `Range` pointing to the `Buffer`s data.
+  ByteRange range() const {
+    return range_;
+  }
+  /// Returns a mutable `Range` pointing to the `Buffer`s data.
+  MutableByteRange range() {
+    return range_;
+  }
+
+  const unsigned char* data() const {
+    return range_.data();
+  }
+
+  unsigned char* data() {
+    return range_.data();
+  }
+
+  std::size_t size() const {
+    return range_.size();
+  }
+
+  bool empty() const {
+    return range_.empty();
+  }
+};
+}

contrib/pzstd/utils/FileSystem.h

@@ -0,0 +1,61 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#pragma once
+
+#include "utils/Range.h"
+
+#include <sys/stat.h>
+#include <cstdint>
+#include <system_error>
+
+// A small subset of `std::filesystem`.
+// `std::filesystem` should be a drop in replacement.
+// See http://en.cppreference.com/w/cpp/filesystem for documentation.
+
+namespace pzstd {
+
+using file_status = struct stat;
+
+/// http://en.cppreference.com/w/cpp/filesystem/status
+inline file_status status(StringPiece path, std::error_code& ec) noexcept {
+  file_status status;
+  if (stat(path.data(), &status)) {
+    ec.assign(errno, std::generic_category());
+  } else {
+    ec.clear();
+  }
+  return status;
+}
+
+/// http://en.cppreference.com/w/cpp/filesystem/is_regular_file
+inline bool is_regular_file(file_status status) noexcept {
+  return S_ISREG(status.st_mode);
+}
+
+/// http://en.cppreference.com/w/cpp/filesystem/is_regular_file
+inline bool is_regular_file(StringPiece path, std::error_code& ec) noexcept {
+  return is_regular_file(status(path, ec));
+}
+
+/// http://en.cppreference.com/w/cpp/filesystem/file_size
+inline std::uintmax_t file_size(
+    StringPiece path,
+    std::error_code& ec) noexcept {
+  auto stat = status(path, ec);
+  if (ec) {
+    return -1;
+  }
+  if (!is_regular_file(stat)) {
+    ec.assign(ENOTSUP, std::generic_category());
+    return -1;
+  }
+  ec.clear();
+  return stat.st_size;
+}
+}

contrib/pzstd/utils/Likely.h

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+ 
+/**
+ * Compiler hints to indicate the fast path of an "if" branch: whether
+ * the if condition is likely to be true or false.
+ *
+ * @author Tudor Bosman (tudorb@fb.com)
+ */
+
+#pragma once
+
+#undef LIKELY
+#undef UNLIKELY
+
+#if defined(__GNUC__) && __GNUC__ >= 4
+#define LIKELY(x) (__builtin_expect((x), 1))
+#define UNLIKELY(x) (__builtin_expect((x), 0))
+#else
+#define LIKELY(x) (x)
+#define UNLIKELY(x) (x)
+#endif

contrib/pzstd/utils/Range.h

@@ -0,0 +1,130 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+ 
+/**
+ * A subset of `folly/Range.h`.
+ * All code copied verbatiam modulo formatting
+ */
+#pragma once
+
+#include "utils/Likely.h"
+
+#include <cstddef>
+#include <stdexcept>
+#include <string>
+#include <type_traits>
+
+namespace pzstd {
+
+namespace detail {
+/*
+ *Use IsCharPointer<T>::type to enable const char* or char*.
+ *Use IsCharPointer<T>::const_type to enable only const char*.
+*/
+template <class T>
+struct IsCharPointer {};
+
+template <>
+struct IsCharPointer<char*> {
+  typedef int type;
+};
+
+template <>
+struct IsCharPointer<const char*> {
+  typedef int const_type;
+  typedef int type;
+};
+
+} // namespace detail
+
+template <typename Iter>
+class Range {
+  Iter b_;
+  Iter e_;
+
+ public:
+  using size_type = std::size_t;
+  using iterator = Iter;
+  using const_iterator = Iter;
+  using value_type = typename std::remove_reference<
+      typename std::iterator_traits<Iter>::reference>::type;
+  using reference = typename std::iterator_traits<Iter>::reference;
+
+  constexpr Range() : b_(), e_() {}
+  constexpr Range(Iter begin, Iter end) : b_(begin), e_(end) {}
+
+  constexpr Range(Iter begin, size_type size) : b_(begin), e_(begin + size) {}
+
+  template <class T = Iter, typename detail::IsCharPointer<T>::type = 0>
+  /* implicit */ Range(Iter str) : b_(str), e_(str + std::strlen(str)) {}
+
+  template <class T = Iter, typename detail::IsCharPointer<T>::const_type = 0>
+  /* implicit */ Range(const std::string& str)
+      : b_(str.data()), e_(b_ + str.size()) {}
+
+  // Allow implicit conversion from Range<From> to Range<To> if From is
+  // implicitly convertible to To.
+  template <
+      class OtherIter,
+      typename std::enable_if<
+          (!std::is_same<Iter, OtherIter>::value &&
+           std::is_convertible<OtherIter, Iter>::value),
+          int>::type = 0>
+  constexpr /* implicit */ Range(const Range<OtherIter>& other)
+      : b_(other.begin()), e_(other.end()) {}
+
+  Range(const Range&) = default;
+  Range(Range&&) = default;
+
+  Range& operator=(const Range&) & = default;
+  Range& operator=(Range&&) & = default;
+
+  constexpr size_type size() const {
+    return e_ - b_;
+  }
+  bool empty() const {
+    return b_ == e_;
+  }
+  Iter data() const {
+    return b_;
+  }
+  Iter begin() const {
+    return b_;
+  }
+  Iter end() const {
+    return e_;
+  }
+
+  void advance(size_type n) {
+    if (UNLIKELY(n > size())) {
+      throw std::out_of_range("index out of range");
+    }
+    b_ += n;
+  }
+
+  void subtract(size_type n) {
+    if (UNLIKELY(n > size())) {
+      throw std::out_of_range("index out of range");
+    }
+    e_ -= n;
+  }
+
+  Range subpiece(size_type first, size_type length = std::string::npos) const {
+    if (UNLIKELY(first > size())) {
+      throw std::out_of_range("index out of range");
+    }
+
+    return Range(b_ + first, std::min(length, size() - first));
+  }
+};
+
+using ByteRange = Range<const unsigned char*>;
+using MutableByteRange = Range<unsigned char*>;
+using StringPiece = Range<const char*>;
+}

contrib/pzstd/utils/ScopeGuard.h

@@ -0,0 +1,50 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#pragma once
+
+#include <utility>
+
+namespace pzstd {
+
+/**
+ * Dismissable scope guard.
+ * `Function` must be callable and take no parameters.
+ * Unless `dissmiss()` is called, the callable is executed upon destruction of
+ * `ScopeGuard`.
+ *
+ * Example:
+ *
+ *   auto guard = makeScopeGuard([&] { cleanup(); });
+ */
+template <typename Function>
+class ScopeGuard {
+  Function function;
+  bool dismissed;
+
+ public:
+  explicit ScopeGuard(Function&& function)
+      : function(std::move(function)), dismissed(false) {}
+
+  void dismiss() {
+    dismissed = true;
+  }
+
+  ~ScopeGuard() noexcept {
+    if (!dismissed) {
+      function();
+    }
+  }
+};
+
+/// Creates a scope guard from `function`.
+template <typename Function>
+ScopeGuard<Function> makeScopeGuard(Function&& function) {
+  return ScopeGuard<Function>(std::forward<Function>(function));
+}
+}

contrib/pzstd/utils/ThreadPool.h

@@ -0,0 +1,58 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#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([&] {
+        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));
+  }
+};
+}

contrib/pzstd/utils/WorkQueue.h

@@ -0,0 +1,144 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#pragma once
+
+#include "utils/Buffer.h"
+
+#include <atomic>
+#include <cassert>
+#include <condition_variable>
+#include <cstddef>
+#include <functional>
+#include <mutex>
+#include <queue>
+
+namespace pzstd {
+
+/// Unbounded thread-safe work queue.
+template <typename T>
+class WorkQueue {
+  // Protects all member variable access
+  std::mutex mutex_;
+  std::condition_variable cv_;
+
+  std::queue<T> queue_;
+  bool done_;
+
+ public:
+  /// Constructs an empty work queue.
+  WorkQueue() : done_(false) {}
+
+  /**
+   * Push an item onto the work queue.  Notify a single thread that work is
+   * available.  If `finish()` has been called, do nothing and return false.
+   *
+   * @param item  Item to push onto the queue.
+   * @returns     True upon success, false if `finish()` has been called.  An
+   *               item was pushed iff `push()` returns true.
+   */
+  bool push(T item) {
+    {
+      std::lock_guard<std::mutex> lock(mutex_);
+      if (done_) {
+        return false;
+      }
+      queue_.push(std::move(item));
+    }
+    cv_.notify_one();
+    return true;
+  }
+
+  /**
+   * Attempts to pop an item off the work queue.  It will block until data is
+   * available or `finish()` has been called.
+   *
+   * @param[out] item  If `pop` returns `true`, it contains the popped item.
+   *                    If `pop` returns `false`, it is unmodified.
+   * @returns          True upon success.  False if the queue is empty and
+   *                    `finish()` has been called.
+   */
+  bool pop(T& item) {
+    std::unique_lock<std::mutex> lock(mutex_);
+    while (queue_.empty() && !done_) {
+      cv_.wait(lock);
+    }
+    if (queue_.empty()) {
+      assert(done_);
+      return false;
+    }
+    item = std::move(queue_.front());
+    queue_.pop();
+    return true;
+  }
+
+  /**
+   * Promise that `push()` won't be called again, so once the queue is empty
+   * there will never any more work.
+   */
+  void finish() {
+    {
+      std::lock_guard<std::mutex> lock(mutex_);
+      assert(!done_);
+      done_ = true;
+    }
+    cv_.notify_all();
+  }
+
+  /// Blocks until `finish()` has been called (but the queue may not be empty).
+  void waitUntilFinished() {
+    std::unique_lock<std::mutex> lock(mutex_);
+    while (!done_) {
+      cv_.wait(lock);
+      // If we were woken by a push, we need to wake a thread waiting on pop().
+      if (!done_) {
+        lock.unlock();
+        cv_.notify_one();
+        lock.lock();
+      }
+    }
+  }
+};
+
+/// Work queue for `Buffer`s that knows the total number of bytes in the queue.
+class BufferWorkQueue {
+  WorkQueue<Buffer> queue_;
+  std::atomic<std::size_t> size_;
+
+ public:
+  BufferWorkQueue() : size_(0) {}
+
+  void push(Buffer buffer) {
+    size_.fetch_add(buffer.size());
+    queue_.push(std::move(buffer));
+  }
+
+  bool pop(Buffer& buffer) {
+    bool result = queue_.pop(buffer);
+    if (result) {
+      size_.fetch_sub(buffer.size());
+    }
+    return result;
+  }
+
+  void finish() {
+    queue_.finish();
+  }
+
+  /**
+   * Blocks until `finish()` has been called.
+   *
+   * @returns The total number of bytes of all the `Buffer`s currently in the
+   *           queue.
+   */
+  std::size_t size() {
+    queue_.waitUntilFinished();
+    return size_.load();
+  }
+};
+}

contrib/pzstd/utils/test/BufferTest.cpp

@@ -0,0 +1,89 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include "utils/Buffer.h"
+#include "utils/Range.h"
+
+#include <gtest/gtest.h>
+#include <memory>
+
+using namespace pzstd;
+
+namespace {
+void deleter(const unsigned char* buf) {
+  delete[] buf;
+}
+}
+
+TEST(Buffer, Constructors) {
+  Buffer empty;
+  EXPECT_TRUE(empty.empty());
+  EXPECT_EQ(0, empty.size());
+
+  Buffer sized(5);
+  EXPECT_FALSE(sized.empty());
+  EXPECT_EQ(5, sized.size());
+
+  Buffer moved(std::move(sized));
+  EXPECT_FALSE(sized.empty());
+  EXPECT_EQ(5, sized.size());
+
+  Buffer assigned;
+  assigned = std::move(moved);
+  EXPECT_FALSE(sized.empty());
+  EXPECT_EQ(5, sized.size());
+}
+
+TEST(Buffer, BufferManagement) {
+  std::shared_ptr<unsigned char> buf(new unsigned char[10], deleter);
+  {
+    Buffer acquired(buf, MutableByteRange(buf.get(), buf.get() + 10));
+    EXPECT_EQ(2, buf.use_count());
+    Buffer moved(std::move(acquired));
+    EXPECT_EQ(2, buf.use_count());
+    Buffer assigned;
+    assigned = std::move(moved);
+    EXPECT_EQ(2, buf.use_count());
+
+    Buffer split = assigned.splitAt(5);
+    EXPECT_EQ(3, buf.use_count());
+
+    split.advance(1);
+    assigned.subtract(1);
+    EXPECT_EQ(3, buf.use_count());
+  }
+  EXPECT_EQ(1, buf.use_count());
+}
+
+TEST(Buffer, Modifiers) {
+  Buffer buf(10);
+  {
+    unsigned char i = 0;
+    for (auto& byte : buf.range()) {
+      byte = i++;
+    }
+  }
+
+  auto prefix = buf.splitAt(2);
+
+  ASSERT_EQ(2, prefix.size());
+  EXPECT_EQ(0, *prefix.data());
+
+  ASSERT_EQ(8, buf.size());
+  EXPECT_EQ(2, *buf.data());
+
+  buf.advance(2);
+  EXPECT_EQ(4, *buf.data());
+
+  EXPECT_EQ(9, *(buf.range().end() - 1));
+
+  buf.subtract(2);
+  EXPECT_EQ(7, *(buf.range().end() - 1));
+
+  EXPECT_EQ(4, buf.size());
+}

contrib/pzstd/utils/test/Makefile

@@ -0,0 +1,41 @@
+# ##########################################################################
+# Copyright (c) 2016-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+# ##########################################################################
+
+GTEST_INC ?= -isystem googletest/googletest/include
+GTEST_LIB ?= -L googletest/build/googlemock/gtest
+
+# Define *.exe as extension for Windows systems
+ifneq (,$(filter Windows%,$(OS)))
+EXT =.exe
+else
+EXT =
+endif
+
+PZSTDDIR = ../..
+
+CPPFLAGS = -I$(PZSTDDIR) $(GTEST_INC) $(GTEST_LIB)
+CFLAGS  ?= -O3
+CFLAGS  += -std=c++11
+CFLAGS  += $(MOREFLAGS)
+FLAGS    = $(CPPFLAGS) $(CFLAGS) $(LDFLAGS)
+
+%: %.cpp
+	$(CXX) $(FLAGS) -lgtest -lgtest_main $^ -o $@$(EXT)
+
+.PHONY: test clean
+
+test: BufferTest RangeTest ScopeGuardTest ThreadPoolTest WorkQueueTest
+	@./BufferTest$(EXT)
+	@./RangeTest$(EXT)
+	@./ScopeGuardTest$(EXT)
+	@./ThreadPoolTest$(EXT)
+	@./WorkQueueTest$(EXT)
+
+clean:
+	@rm -f BufferTest RangeTest ScopeGuardTest ThreadPoolTest WorkQueueTest

contrib/pzstd/utils/test/RangeTest.cpp

@@ -0,0 +1,82 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include "utils/Range.h"
+
+#include <gtest/gtest.h>
+#include <string>
+
+using namespace pzstd;
+
+// Range is directly copied from folly.
+// Just some sanity tests to make sure everything seems to work.
+
+TEST(Range, Constructors) {
+  StringPiece empty;
+  EXPECT_TRUE(empty.empty());
+  EXPECT_EQ(0, empty.size());
+
+  std::string str = "hello";
+  {
+    Range<std::string::const_iterator> piece(str.begin(), str.end());
+    EXPECT_EQ(5, piece.size());
+    EXPECT_EQ('h', *piece.data());
+    EXPECT_EQ('o', *(piece.end() - 1));
+  }
+
+  {
+    StringPiece piece(str.data(), str.size());
+    EXPECT_EQ(5, piece.size());
+    EXPECT_EQ('h', *piece.data());
+    EXPECT_EQ('o', *(piece.end() - 1));
+  }
+
+  {
+    StringPiece piece(str);
+    EXPECT_EQ(5, piece.size());
+    EXPECT_EQ('h', *piece.data());
+    EXPECT_EQ('o', *(piece.end() - 1));
+  }
+
+  {
+    StringPiece piece(str.c_str());
+    EXPECT_EQ(5, piece.size());
+    EXPECT_EQ('h', *piece.data());
+    EXPECT_EQ('o', *(piece.end() - 1));
+  }
+}
+
+TEST(Range, Modifiers) {
+  StringPiece range("hello world");
+  ASSERT_EQ(11, range.size());
+
+  {
+    auto hello = range.subpiece(0, 5);
+    EXPECT_EQ(5, hello.size());
+    EXPECT_EQ('h', *hello.data());
+    EXPECT_EQ('o', *(hello.end() - 1));
+  }
+  {
+    auto hello = range;
+    hello.subtract(6);
+    EXPECT_EQ(5, hello.size());
+    EXPECT_EQ('h', *hello.data());
+    EXPECT_EQ('o', *(hello.end() - 1));
+  }
+  {
+    auto world = range;
+    world.advance(6);
+    EXPECT_EQ(5, world.size());
+    EXPECT_EQ('w', *world.data());
+    EXPECT_EQ('d', *(world.end() - 1));
+  }
+
+  std::string expected = "hello world";
+  EXPECT_EQ(expected, std::string(range.begin(), range.end()));
+  EXPECT_EQ(expected, std::string(range.data(), range.size()));
+}

contrib/pzstd/utils/test/ScopeGuardTest.cpp

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include "utils/ScopeGuard.h"
+
+#include <gtest/gtest.h>
+
+using namespace pzstd;
+
+TEST(ScopeGuard, Dismiss) {
+  {
+    auto guard = makeScopeGuard([&] { EXPECT_TRUE(false); });
+    guard.dismiss();
+  }
+}
+
+TEST(ScopeGuard, Executes) {
+  bool executed = false;
+  {
+    auto guard = makeScopeGuard([&] { executed = true; });
+  }
+  EXPECT_TRUE(executed);
+}

contrib/pzstd/utils/test/ThreadPoolTest.cpp

@@ -0,0 +1,67 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include "utils/ThreadPool.h"
+
+#include <gtest/gtest.h>
+#include <atomic>
+#include <thread>
+#include <vector>
+
+using namespace pzstd;
+
+TEST(ThreadPool, Ordering) {
+  std::vector<int> results;
+
+  {
+    ThreadPool executor(1);
+    for (int i = 0; i < 100; ++i) {
+      executor.add([ &results, i ] { results.push_back(i); });
+    }
+  }
+
+  for (int i = 0; i < 100; ++i) {
+    EXPECT_EQ(i, results[i]);
+  }
+}
+
+TEST(ThreadPool, AllJobsFinished) {
+  std::atomic<unsigned> numFinished{0};
+  std::atomic<bool> start{false};
+  {
+    ThreadPool executor(5);
+    for (int i = 0; i < 1000; ++i) {
+      executor.add([ &numFinished, &start ] {
+        while (!start.load()) {
+          // spin
+        }
+        ++numFinished;
+      });
+    }
+    start.store(true);
+  }
+  EXPECT_EQ(1000, numFinished.load());
+}
+
+TEST(ThreadPool, AddJobWhileJoining) {
+  std::atomic<bool> done{false};
+  {
+    ThreadPool executor(1);
+    executor.add([&executor, &done] {
+      while (!done.load()) {
+        std::this_thread::yield();
+      }
+      // Sleep for a second to be sure that we are joining
+      std::this_thread::sleep_for(std::chrono::seconds(1));
+      executor.add([] {
+        EXPECT_TRUE(false);
+      });
+    });
+    done.store(true);
+  }
+}

contrib/pzstd/utils/test/WorkQueueTest.cpp

@@ -0,0 +1,176 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include "utils/Buffer.h"
+#include "utils/WorkQueue.h"
+
+#include <gtest/gtest.h>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+using namespace pzstd;
+
+namespace {
+struct Popper {
+  WorkQueue<int>* queue;
+  int* results;
+  std::mutex* mutex;
+
+  void operator()() {
+    int result;
+    while (queue->pop(result)) {
+      std::lock_guard<std::mutex> lock(*mutex);
+      results[result] = result;
+    }
+  }
+};
+}
+
+TEST(WorkQueue, SingleThreaded) {
+  WorkQueue<int> queue;
+  int result;
+
+  queue.push(5);
+  EXPECT_TRUE(queue.pop(result));
+  EXPECT_EQ(5, result);
+
+  queue.push(1);
+  queue.push(2);
+  EXPECT_TRUE(queue.pop(result));
+  EXPECT_EQ(1, result);
+  EXPECT_TRUE(queue.pop(result));
+  EXPECT_EQ(2, result);
+
+  queue.push(1);
+  queue.push(2);
+  queue.finish();
+  EXPECT_TRUE(queue.pop(result));
+  EXPECT_EQ(1, result);
+  EXPECT_TRUE(queue.pop(result));
+  EXPECT_EQ(2, result);
+  EXPECT_FALSE(queue.pop(result));
+
+  queue.waitUntilFinished();
+}
+
+TEST(WorkQueue, SPSC) {
+  WorkQueue<int> queue;
+  const int max = 100;
+
+  for (int i = 0; i < 10; ++i) {
+    queue.push(i);
+  }
+
+  std::thread thread([ &queue, max ] {
+    int result;
+    for (int i = 0;; ++i) {
+      if (!queue.pop(result)) {
+        EXPECT_EQ(i, max);
+        break;
+      }
+      EXPECT_EQ(i, result);
+    }
+  });
+
+  std::this_thread::yield();
+  for (int i = 10; i < max; ++i) {
+    queue.push(i);
+  }
+  queue.finish();
+
+  thread.join();
+}
+
+TEST(WorkQueue, SPMC) {
+  WorkQueue<int> queue;
+  std::vector<int> results(10000, -1);
+  std::mutex mutex;
+  std::vector<std::thread> threads;
+  for (int i = 0; i < 100; ++i) {
+    threads.emplace_back(Popper{&queue, results.data(), &mutex});
+  }
+
+  for (int i = 0; i < 10000; ++i) {
+    queue.push(i);
+  }
+  queue.finish();
+
+  for (auto& thread : threads) {
+    thread.join();
+  }
+
+  for (int i = 0; i < 10000; ++i) {
+    EXPECT_EQ(i, results[i]);
+  }
+}
+
+TEST(WorkQueue, MPMC) {
+  WorkQueue<int> queue;
+  std::vector<int> results(10000, -1);
+  std::mutex mutex;
+  std::vector<std::thread> popperThreads;
+  for (int i = 0; i < 100; ++i) {
+    popperThreads.emplace_back(Popper{&queue, results.data(), &mutex});
+  }
+
+  std::vector<std::thread> pusherThreads;
+  for (int i = 0; i < 10; ++i) {
+    auto min = i * 1000;
+    auto max = (i + 1) * 1000;
+    pusherThreads.emplace_back(
+        [ &queue, min, max ] {
+          for (int i = min; i < max; ++i) {
+            queue.push(i);
+          }
+        });
+  }
+
+  for (auto& thread : pusherThreads) {
+    thread.join();
+  }
+  queue.finish();
+
+  for (auto& thread : popperThreads) {
+    thread.join();
+  }
+
+  for (int i = 0; i < 10000; ++i) {
+    EXPECT_EQ(i, results[i]);
+  }
+}
+
+TEST(BufferWorkQueue, SizeCalculatedCorrectly) {
+  {
+    BufferWorkQueue queue;
+    queue.finish();
+    EXPECT_EQ(0, queue.size());
+  }
+  {
+    BufferWorkQueue queue;
+    queue.push(Buffer(10));
+    queue.finish();
+    EXPECT_EQ(10, queue.size());
+  }
+  {
+    BufferWorkQueue queue;
+    queue.push(Buffer(10));
+    queue.push(Buffer(5));
+    queue.finish();
+    EXPECT_EQ(15, queue.size());
+  }
+  {
+    BufferWorkQueue queue;
+    queue.push(Buffer(10));
+    queue.push(Buffer(5));
+    queue.finish();
+    Buffer buffer;
+    queue.pop(buffer);
+    EXPECT_EQ(5, queue.size());
+  }
+}