Update files

cpp/thirdpart/kenlm/util/stream/io.cc

+#include "io.hh"
+
+#include "../file.hh"
+#include "chain.hh"
+
+#include <cstddef>
+
+namespace util {
+namespace stream {
+
+ReadSizeException::ReadSizeException() throw() {}
+ReadSizeException::~ReadSizeException() throw() {}
+
+void Read::Run(const ChainPosition &position) {
+  const std::size_t block_size = position.GetChain().BlockSize();
+  const std::size_t entry_size = position.GetChain().EntrySize();
+  for (Link link(position); link; ++link) {
+    std::size_t got = util::ReadOrEOF(file_, link->Get(), block_size);
+    UTIL_THROW_IF(got % entry_size, ReadSizeException, "File ended with " << got << " bytes, not a multiple of " << entry_size << ".");
+    if (got == 0) {
+      link.Poison();
+      return;
+    } else {
+      link->SetValidSize(got);
+    }
+  }
+}
+
+void PRead::Run(const ChainPosition &position) {
+  scoped_fd owner;
+  if (own_) owner.reset(file_);
+  const uint64_t size = SizeOrThrow(file_);
+  UTIL_THROW_IF(size % static_cast<uint64_t>(position.GetChain().EntrySize()), ReadSizeException, "File size " << file_ << " size is " << size << " not a multiple of " << position.GetChain().EntrySize());
+  const std::size_t block_size = position.GetChain().BlockSize();
+  const uint64_t block_size64 = static_cast<uint64_t>(block_size);
+  Link link(position);
+  uint64_t offset = 0;
+  for (; offset + block_size64 < size; offset += block_size64, ++link) {
+    ErsatzPRead(file_, link->Get(), block_size, offset);
+    link->SetValidSize(block_size);
+  }
+  // size - offset is <= block_size, so it casts to 32-bit fine.
+  if (size - offset) {
+    ErsatzPRead(file_, link->Get(), size - offset, offset);
+    link->SetValidSize(size - offset);
+    ++link;
+  }
+  link.Poison();
+}
+
+void Write::Run(const ChainPosition &position) {
+  for (Link link(position); link; ++link) {
+    WriteOrThrow(file_, link->Get(), link->ValidSize());
+  }
+}
+
+void WriteAndRecycle::Run(const ChainPosition &position) {
+  const std::size_t block_size = position.GetChain().BlockSize();
+  for (Link link(position); link; ++link) {
+    WriteOrThrow(file_, link->Get(), link->ValidSize());
+    link->SetValidSize(block_size);
+  }
+}
+
+void PWrite::Run(const ChainPosition &position) {
+  uint64_t offset = 0;
+  for (Link link(position); link; ++link) {
+    ErsatzPWrite(file_, link->Get(), link->ValidSize(), offset);
+    offset += link->ValidSize();
+  }
+  // Trim file to size.
+  util::ResizeOrThrow(file_, offset);
+}
+
+} // namespace stream
+} // namespace util

cpp/thirdpart/kenlm/util/stream/io.hh

+#ifndef UTIL_STREAM_IO_H
+#define UTIL_STREAM_IO_H
+
+#include "../exception.hh"
+#include "../file.hh"
+
+namespace util {
+namespace stream {
+
+class ChainPosition;
+
+class ReadSizeException : public util::Exception {
+  public:
+    ReadSizeException() throw();
+    ~ReadSizeException() throw();
+};
+
+class Read {
+  public:
+    explicit Read(int fd) : file_(fd) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+};
+
+// Like read but uses pread so that the file can be accessed from multiple threads.
+class PRead {
+  public:
+    explicit PRead(int fd, bool take_own = false) : file_(fd), own_(take_own) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+    bool own_;
+};
+
+class Write {
+  public:
+    explicit Write(int fd) : file_(fd) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+};
+
+// It's a common case that stuff is written and then recycled.  So rather than
+// spawn another thread to Recycle, this combines the two roles.
+class WriteAndRecycle {
+  public:
+    explicit WriteAndRecycle(int fd) : file_(fd) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+};
+
+class PWrite {
+  public:
+    explicit PWrite(int fd) : file_(fd) {}
+    void Run(const ChainPosition &position);
+  private:
+    int file_;
+};
+
+
+// Reuse the same file over and over again to buffer output.
+class FileBuffer {
+  public:
+    explicit FileBuffer(int fd) : file_(fd) {}
+
+    PWrite Sink() const {
+      util::SeekOrThrow(file_.get(), 0);
+      return PWrite(file_.get());
+    }
+
+    PRead Source(bool discard = false) {
+      return PRead(discard ? file_.release() : file_.get(), discard);
+    }
+
+    uint64_t Size() const {
+      return SizeOrThrow(file_.get());
+    }
+
+  private:
+    scoped_fd file_;
+};
+
+} // namespace stream
+} // namespace util
+#endif // UTIL_STREAM_IO_H

cpp/thirdpart/kenlm/util/stream/io_test.cc

+#include "io.hh"
+
+#include "chain.hh"
+#include "../file.hh"
+
+#define BOOST_TEST_MODULE IOTest
+#include <boost/test/unit_test.hpp>
+
+#include <unistd.h>
+
+namespace util { namespace stream { namespace {
+
+BOOST_AUTO_TEST_CASE(CopyFile) {
+  std::string temps("io_test_temp");
+
+  scoped_fd in(MakeTemp(temps));
+  for (uint64_t i = 0; i < 100000; ++i) {
+    WriteOrThrow(in.get(), &i, sizeof(uint64_t));
+  }
+  SeekOrThrow(in.get(), 0);
+  scoped_fd out(MakeTemp(temps));
+
+  ChainConfig config;
+  config.entry_size = 8;
+  config.total_memory = 1024;
+  config.block_count = 10;
+
+  Chain(config) >> PRead(in.get()) >> Write(out.get());
+
+  SeekOrThrow(out.get(), 0);
+  for (uint64_t i = 0; i < 100000; ++i) {
+    uint64_t got;
+    ReadOrThrow(out.get(), &got, sizeof(uint64_t));
+    BOOST_CHECK_EQUAL(i, got);
+  }
+}
+
+}}} // namespaces

cpp/thirdpart/kenlm/util/stream/line_input.cc

+#include "line_input.hh"
+
+#include "../exception.hh"
+#include "../file.hh"
+#include "../read_compressed.hh"
+#include "chain.hh"
+
+#include <algorithm>
+#include <vector>
+
+namespace util { namespace stream {
+
+void LineInput::Run(const ChainPosition &position) {
+  ReadCompressed reader(fd_);
+  // Holding area for beginning of line to be placed in next block.
+  std::vector<char> carry;
+
+  for (Link block(position); ; ++block) {
+    char *to = static_cast<char*>(block->Get());
+    char *begin = to;
+    char *end = to + position.GetChain().BlockSize();
+    std::copy(carry.begin(), carry.end(), to);
+    to += carry.size();
+    while (to != end) {
+      std::size_t got = reader.Read(to, end - to);
+      if (!got) {
+        // EOF
+        block->SetValidSize(to - begin);
+        ++block;
+        block.Poison();
+        return;
+      }
+      to += got;
+    }
+
+    // Find the last newline.
+    char *newline;
+    for (newline = to - 1; ; --newline) {
+      UTIL_THROW_IF(newline < begin, Exception, "Did not find a newline in " << position.GetChain().BlockSize() << " bytes of input of " << NameFromFD(fd_) << ".  Is this a text file?");
+      if (*newline == '\n') break;
+    }
+
+    // Copy everything after the last newline to the carry.
+    carry.clear();
+    carry.resize(to - (newline + 1));
+    std::copy(newline + 1, to, &*carry.begin());
+
+    block->SetValidSize(newline + 1 - begin);
+  }
+}
+
+}} // namespaces

cpp/thirdpart/kenlm/util/stream/line_input.hh

+#ifndef UTIL_STREAM_LINE_INPUT_H
+#define UTIL_STREAM_LINE_INPUT_H
+namespace util {namespace stream {
+
+class ChainPosition;
+
+/* Worker that reads input into blocks, ensuring that blocks contain whole
+ * lines.  Assumes that the maximum size of a line is less than the block size
+ */
+class LineInput {
+  public:
+    // Takes ownership upon thread execution.
+    explicit LineInput(int fd);
+
+    void Run(const ChainPosition &position);
+
+  private:
+    int fd_;
+};
+
+}} // namespaces
+#endif // UTIL_STREAM_LINE_INPUT_H

cpp/thirdpart/kenlm/util/stream/multi_progress.cc

+#include "multi_progress.hh"
+
+// TODO: merge some functionality with the simple progress bar?
+#include "../ersatz_progress.hh"
+
+#include <iostream>
+#include <limits>
+
+#include <cstring>
+
+#if !defined(_WIN32) && !defined(_WIN64)
+#include <unistd.h>
+#endif
+
+namespace util { namespace stream {
+
+namespace {
+const char kDisplayCharacters[] = "-+*#0123456789";
+
+uint64_t Next(unsigned char stone, uint64_t complete) {
+  return (static_cast<uint64_t>(stone + 1) * complete + MultiProgress::kWidth - 1) / MultiProgress::kWidth;
+}
+
+} // namespace
+
+MultiProgress::MultiProgress() : active_(false), complete_(std::numeric_limits<uint64_t>::max()), character_handout_(0) {}
+
+MultiProgress::~MultiProgress() {
+  if (active_ && complete_ != std::numeric_limits<uint64_t>::max())
+    std::cerr << '\n';
+}
+
+void MultiProgress::Activate() {
+  active_ =
+#if !defined(_WIN32) && !defined(_WIN64)
+    // Is stderr a terminal?
+    (isatty(2) == 1)
+#else
+    true
+#endif
+    ;
+}
+
+void MultiProgress::SetTarget(uint64_t complete) {
+  if (!active_) return;
+  complete_ = complete;
+  if (!complete) complete_ = 1;
+  memset(display_, 0, sizeof(display_));
+  character_handout_ = 0;
+  std::cerr << kProgressBanner;
+}
+
+WorkerProgress MultiProgress::Add() {
+  if (!active_)
+    return WorkerProgress(std::numeric_limits<uint64_t>::max(), *this, '\0');
+  std::size_t character_index;
+  {
+    boost::unique_lock<boost::mutex> lock(mutex_);
+    character_index = character_handout_++;
+    if (character_handout_ == sizeof(kDisplayCharacters) - 1)
+      character_handout_ = 0;
+  }
+  return WorkerProgress(Next(0, complete_), *this, kDisplayCharacters[character_index]);
+}
+
+void MultiProgress::Finished() {
+  if (!active_ || complete_ == std::numeric_limits<uint64_t>::max()) return;
+  std::cerr << '\n';
+  complete_ = std::numeric_limits<uint64_t>::max();
+}
+
+void MultiProgress::Milestone(WorkerProgress &worker) {
+  if (!active_ || complete_ == std::numeric_limits<uint64_t>::max()) return;
+  unsigned char stone = std::min(static_cast<uint64_t>(kWidth), worker.current_ * kWidth / complete_);
+  for (char *i = &display_[worker.stone_]; i < &display_[stone]; ++i) {
+    *i = worker.character_;
+  }
+  worker.next_ = Next(stone, complete_);
+  worker.stone_ = stone;
+  {
+    boost::unique_lock<boost::mutex> lock(mutex_);
+    std::cerr << '\r' << display_ << std::flush;
+  }
+}
+
+}} // namespaces

cpp/thirdpart/kenlm/util/stream/multi_progress.hh

+/* Progress bar suitable for chains of workers */
+#ifndef UTIL_STREAM_MULTI_PROGRESS_H
+#define UTIL_STREAM_MULTI_PROGRESS_H
+
+#include <boost/thread/mutex.hpp>
+
+#include <cstddef>
+#include <stdint.h>
+
+namespace util { namespace stream {
+
+class WorkerProgress;
+
+class MultiProgress {
+  public:
+    static const unsigned char kWidth = 100;
+
+    MultiProgress();
+
+    ~MultiProgress();
+
+    // Turns on showing (requires SetTarget too).
+    void Activate();
+
+    void SetTarget(uint64_t complete);
+
+    WorkerProgress Add();
+
+    void Finished();
+
+  private:
+    friend class WorkerProgress;
+    void Milestone(WorkerProgress &worker);
+
+    bool active_;
+
+    uint64_t complete_;
+
+    boost::mutex mutex_;
+
+    // \0 at the end.
+    char display_[kWidth + 1];
+
+    std::size_t character_handout_;
+
+    MultiProgress(const MultiProgress &);
+    MultiProgress &operator=(const MultiProgress &);
+};
+
+class WorkerProgress {
+  public:
+    // Default contrutor must be initialized with operator= later.
+    WorkerProgress() : parent_(NULL) {}
+
+    // Not threadsafe for the same worker by default.
+    WorkerProgress &operator++() {
+      if (++current_ >= next_) {
+        parent_->Milestone(*this);
+      }
+      return *this;
+    }
+
+    WorkerProgress &operator+=(uint64_t amount) {
+      current_ += amount;
+      if (current_ >= next_) {
+        parent_->Milestone(*this);
+      }
+      return *this;
+    }
+
+  private:
+    friend class MultiProgress;
+    WorkerProgress(uint64_t next, MultiProgress &parent, char character)
+      : current_(0), next_(next), parent_(&parent), stone_(0), character_(character) {}
+
+    uint64_t current_, next_;
+
+    MultiProgress *parent_;
+
+    // Previous milestone reached.
+    unsigned char stone_;
+
+    // Character to display in bar.
+    char character_;
+};
+
+}} // namespaces
+
+#endif // UTIL_STREAM_MULTI_PROGRESS_H

cpp/thirdpart/kenlm/util/stream/multi_stream.hh

+#ifndef UTIL_STREAM_MULTI_STREAM_H
+#define UTIL_STREAM_MULTI_STREAM_H
+
+#include "../fixed_array.hh"
+#include "../scoped.hh"
+#include "chain.hh"
+#include "stream.hh"
+
+#include <cstddef>
+#include <new>
+
+#include <cassert>
+#include <cstdlib>
+
+namespace util { namespace stream {
+
+class Chains;
+
+class ChainPositions : public util::FixedArray<util::stream::ChainPosition> {
+  public:
+    ChainPositions() {}
+
+    explicit ChainPositions(std::size_t bound) :
+      util::FixedArray<util::stream::ChainPosition>(bound) {}
+
+    void Init(Chains &chains);
+
+    explicit ChainPositions(Chains &chains) {
+      Init(chains);
+    }
+};
+
+class Chains : public util::FixedArray<util::stream::Chain> {
+  private:
+    template <class T, void (T::*ptr)(const ChainPositions &) = &T::Run> struct CheckForRun {
+      typedef Chains type;
+    };
+
+  public:
+    // Must call Init.
+    Chains() {}
+
+    explicit Chains(std::size_t limit) : util::FixedArray<util::stream::Chain>(limit) {}
+
+    template <class Worker> typename CheckForRun<Worker>::type &operator>>(const Worker &worker) {
+      threads_.push_back(new util::stream::Thread(ChainPositions(*this), worker));
+      return *this;
+    }
+
+    template <class Worker> typename CheckForRun<Worker>::type &operator>>(const boost::reference_wrapper<Worker> &worker) {
+      threads_.push_back(new util::stream::Thread(ChainPositions(*this), worker));
+      return *this;
+    }
+
+    Chains &operator>>(const util::stream::Recycler &recycler) {
+      for (util::stream::Chain *i = begin(); i != end(); ++i)
+        *i >> recycler;
+      return *this;
+    }
+
+    void Wait(bool release_memory = true) {
+      threads_.clear();
+      for (util::stream::Chain *i = begin(); i != end(); ++i) {
+        i->Wait(release_memory);
+      }
+    }
+
+  private:
+    boost::ptr_vector<util::stream::Thread> threads_;
+
+    Chains(const Chains &);
+    void operator=(const Chains &);
+};
+
+inline void ChainPositions::Init(Chains &chains) {
+  util::FixedArray<util::stream::ChainPosition>::Init(chains.size());
+  for (util::stream::Chain *i = chains.begin(); i != chains.end(); ++i) {
+    // use "placement new" syntax to initalize ChainPosition in an already-allocated memory location
+    new (end()) util::stream::ChainPosition(i->Add()); Constructed();
+  }
+}
+
+inline Chains &operator>>(Chains &chains, ChainPositions &positions) {
+  positions.Init(chains);
+  return chains;
+}
+
+template <class T> class GenericStreams : public util::FixedArray<T> {
+  private:
+    typedef util::FixedArray<T> P;
+  public:
+    GenericStreams() {}
+
+    // Limit restricts to positions[0,limit)
+    void Init(const ChainPositions &positions, std::size_t limit) {
+      P::Init(limit);
+      for (const util::stream::ChainPosition *i = positions.begin(); i != positions.begin() + limit; ++i) {
+        P::push_back(*i);
+      }
+    }
+    void Init(const ChainPositions &positions) {
+      Init(positions, positions.size());
+    }
+
+    GenericStreams(const ChainPositions &positions) {
+      Init(positions);
+    }
+
+    void Init(std::size_t amount) {
+      P::Init(amount);
+    }
+};
+
+template <class T> inline Chains &operator>>(Chains &chains, GenericStreams<T> &streams) {
+  ChainPositions positions;
+  chains >> positions;
+  streams.Init(positions);
+  return chains;
+}
+
+typedef GenericStreams<Stream> Streams;
+
+}} // namespaces
+#endif // UTIL_STREAM_MULTI_STREAM_H

cpp/thirdpart/kenlm/util/stream/rewindable_stream.cc

+#include "rewindable_stream.hh"
+#include "../pcqueue.hh"
+
+#include <iostream>
+
+namespace util {
+namespace stream {
+
+RewindableStream::RewindableStream()
+    : current_(NULL), in_(NULL), out_(NULL), poisoned_(true) {
+  // nothing
+}
+
+void RewindableStream::Init(const ChainPosition &position) {
+  UTIL_THROW_IF2(in_, "RewindableStream::Init twice");
+  in_ = position.in_;
+  out_ = position.out_;
+  hit_poison_ = false;
+  poisoned_ = false;
+  progress_ = position.progress_;
+  entry_size_ = position.GetChain().EntrySize();
+  block_size_ = position.GetChain().BlockSize();
+  block_count_ = position.GetChain().BlockCount();
+  blocks_it_ = 0;
+  marked_ = NULL;
+  UTIL_THROW_IF2(block_count_ < 2, "RewindableStream needs block_count at least two");
+  AppendBlock();
+}
+
+RewindableStream &RewindableStream::operator++() {
+  assert(*this);
+  assert(current_ < block_end_);
+  assert(current_);
+  assert(blocks_it_ < blocks_.size());
+  current_ += entry_size_;
+  if (UTIL_UNLIKELY(current_ == block_end_)) {
+    // Fetch another block if necessary.
+    if (++blocks_it_ == blocks_.size()) {
+      if (!marked_) {
+        Flush(blocks_.begin() + blocks_it_);
+        blocks_it_ = 0;
+      }
+      AppendBlock();
+      assert(poisoned_ || (blocks_it_ == blocks_.size() - 1));
+      if (poisoned_) return *this;
+    }
+    Block &cur_block = blocks_[blocks_it_];
+    current_ = static_cast<uint8_t*>(cur_block.Get());
+    block_end_ = current_ + cur_block.ValidSize();
+  }
+  assert(current_);
+  assert(current_ >= static_cast<uint8_t*>(blocks_[blocks_it_].Get()));
+  assert(current_ < block_end_);
+  assert(block_end_ == blocks_[blocks_it_].ValidEnd());
+  return *this;
+}
+
+void RewindableStream::Mark() {
+  marked_ = current_;
+  Flush(blocks_.begin() + blocks_it_);
+  blocks_it_ = 0;
+}
+
+void RewindableStream::Rewind() {
+  if (current_ != marked_) {
+    poisoned_ = false;
+  }
+  blocks_it_ = 0;
+  current_ = marked_;
+  block_end_ = static_cast<const uint8_t*>(blocks_[blocks_it_].ValidEnd());
+
+  assert(current_);
+  assert(current_ >= static_cast<uint8_t*>(blocks_[blocks_it_].Get()));
+  assert(current_ < block_end_);
+  assert(block_end_ == blocks_[blocks_it_].ValidEnd());
+}
+
+void RewindableStream::Poison() {
+  if (blocks_.empty()) return;
+  assert(*this);
+  assert(blocks_it_ == blocks_.size() - 1);
+
+  // Produce all buffered blocks.
+  blocks_.back().SetValidSize(current_ - static_cast<uint8_t*>(blocks_.back().Get()));
+  Flush(blocks_.end());
+  blocks_it_ = 0;
+
+  Block poison;
+  if (!hit_poison_) {
+    in_->Consume(poison);
+  }
+  poison.SetToPoison();
+  out_->Produce(poison);
+  hit_poison_ = true;
+  poisoned_ = true;
+}
+
+void RewindableStream::AppendBlock() {
+  if (UTIL_UNLIKELY(blocks_.size() >= block_count_)) {
+    std::cerr << "RewindableStream trying to use more blocks than available" << std::endl;
+    abort();
+  }
+  if (UTIL_UNLIKELY(hit_poison_)) {
+    poisoned_ = true;
+    return;
+  }
+  Block get;
+  // The loop is needed since it is *feasible* that we're given 0 sized but
+  // valid blocks
+  do {
+    in_->Consume(get);
+    if (UTIL_LIKELY(get)) {
+      blocks_.push_back(get);
+    } else {
+      hit_poison_ = true;
+      poisoned_ = true;
+      return;
+    }
+  } while (UTIL_UNLIKELY(get.ValidSize() == 0));
+  current_ = static_cast<uint8_t*>(blocks_.back().Get());
+  block_end_ = static_cast<const uint8_t*>(blocks_.back().ValidEnd());
+  blocks_it_ = blocks_.size() - 1;
+}
+
+void RewindableStream::Flush(std::deque<Block>::iterator to) {
+  for (std::deque<Block>::iterator i = blocks_.begin(); i != to; ++i) {
+    out_->Produce(*i);
+    progress_ += i->ValidSize();
+  }
+  blocks_.erase(blocks_.begin(), to);
+}
+
+}
+}

cpp/thirdpart/kenlm/util/stream/rewindable_stream.hh

+#ifndef UTIL_STREAM_REWINDABLE_STREAM_H
+#define UTIL_STREAM_REWINDABLE_STREAM_H
+
+#include "chain.hh"
+
+#include <boost/noncopyable.hpp>
+
+#include <deque>
+
+namespace util {
+namespace stream {
+
+/**
+ * A RewindableStream is like a Stream (but one that is only used for
+ * creating input at the start of a chain) except that it can be rewound to
+ * be able to re-write a part of the stream before it is sent. Rewinding
+ * has a limit of 2 * block_size_ - 1 in distance (it does *not* buffer an
+ * entire stream into memory, only a maximum of 2 * block_size_).
+ */
+class RewindableStream : boost::noncopyable {
+  public:
+    /**
+     * Creates an uninitialized RewindableStream. You **must** call Init()
+     * on it later!
+     */
+    RewindableStream();
+
+    ~RewindableStream() {
+      Poison();
+    }
+
+    /**
+     * Initializes an existing RewindableStream at a specific position in
+     * a Chain.
+     *
+     * @param position The position in the chain to get input from and
+     *  produce output on
+     */
+    void Init(const ChainPosition &position);
+
+    /**
+     * Constructs a RewindableStream at a specific position in a Chain all
+     * in one step.
+     *
+     * Equivalent to RewindableStream a(); a.Init(....);
+     */
+    explicit RewindableStream(const ChainPosition &position)
+      : in_(NULL) {
+      Init(position);
+    }
+
+    /**
+     * Gets the record at the current stream position. Const version.
+     */
+    const void *Get() const {
+      assert(!poisoned_);
+      assert(current_);
+      return current_;
+    }
+
+    /**
+     * Gets the record at the current stream position.
+     */
+    void *Get() {
+      assert(!poisoned_);
+      assert(current_);
+      return current_;
+    }
+
+    operator bool() const { return !poisoned_; }
+
+    bool operator!() const { return poisoned_; }
+
+    /**
+     * Marks the current position in the stream to be rewound to later.
+     * Note that you can only rewind back as far as 2 * block_size_ - 1!
+     */
+    void Mark();
+
+    /**
+     * Rewinds the stream back to the marked position. This will throw an
+     * exception if the marked position is too far away.
+     */
+    void Rewind();
+
+    /**
+     * Moves the stream forward to the next record. This internally may
+     * buffer a block for the purposes of rewinding.
+     */
+    RewindableStream& operator++();
+
+    /**
+     * Poisons the stream. This sends any buffered blocks down the chain
+     * and sends a poison block as well (sending at most 2 non-poison and 1
+     * poison block).
+     */
+    void Poison();
+
+  private:
+    void AppendBlock();
+
+    void Flush(std::deque<Block>::iterator to);
+
+    std::deque<Block> blocks_;
+    // current_ is in blocks_[blocks_it_] unless poisoned_.
+    std::size_t blocks_it_;
+
+    std::size_t entry_size_;
+    std::size_t block_size_;
+    std::size_t block_count_;
+
+    uint8_t *marked_, *current_;
+    const uint8_t *block_end_;
+
+    PCQueue<Block> *in_, *out_;
+
+    // Have we hit poison at the end of the stream, even if rewinding?
+    bool hit_poison_;
+    // Is the curren position poison?
+    bool poisoned_;
+
+    WorkerProgress progress_;
+};
+
+inline Chain &operator>>(Chain &chain, RewindableStream &stream) {
+  stream.Init(chain.Add());
+  return chain;
+}
+
+}
+}
+#endif

cpp/thirdpart/kenlm/util/stream/rewindable_stream_test.cc

+#include "io.hh"
+
+#include "rewindable_stream.hh"
+#include "../file.hh"
+
+#define BOOST_TEST_MODULE RewindableStreamTest
+#include <boost/test/unit_test.hpp>
+
+namespace util {
+namespace stream {
+namespace {
+
+BOOST_AUTO_TEST_CASE(RewindableStreamTest) {
+  scoped_fd in(MakeTemp("io_test_temp"));
+  for (uint64_t i = 0; i < 100000; ++i) {
+    WriteOrThrow(in.get(), &i, sizeof(uint64_t));
+  }
+  SeekOrThrow(in.get(), 0);
+
+  ChainConfig config;
+  config.entry_size = 8;
+  config.total_memory = 100;
+  config.block_count = 6;
+
+  Chain chain(config);
+  RewindableStream s;
+  chain >> Read(in.get()) >> s >> kRecycle;
+  uint64_t i = 0;
+  for (; s; ++s, ++i) {
+    BOOST_CHECK_EQUAL(i, *static_cast<const uint64_t*>(s.Get()));
+    if (100000UL - i == 2)
+      s.Mark();
+  }
+  BOOST_CHECK_EQUAL(100000ULL, i);
+  s.Rewind();
+  BOOST_CHECK_EQUAL(100000ULL - 2, *static_cast<const uint64_t*>(s.Get()));
+}
+
+}
+}
+}

cpp/thirdpart/kenlm/util/stream/sort.hh

+/* Usage:
+ * Sort<Compare> sorter(temp, compare);
+ * Chain(config) >> Read(file) >> sorter.Unsorted();
+ * Stream stream;
+ * Chain chain(config) >> sorter.Sorted(internal_config, lazy_config) >> stream;
+ *
+ * Note that sorter must outlive any threads that use Unsorted or Sorted.
+ *
+ * Combiners take the form:
+ * bool operator()(void *into, const void *option, const Compare &compare) const
+ * which returns true iff a combination happened.  The sorting algorithm
+ * guarantees compare(into, option).  But it does not guarantee
+ * compare(option, into).
+ * Currently, combining is only done in merge steps, not during on-the-fly
+ * sort.  Use a hash table for that.
+ */
+
+#ifndef UTIL_STREAM_SORT_H
+#define UTIL_STREAM_SORT_H
+
+#include "chain.hh"
+#include "config.hh"
+#include "io.hh"
+#include "stream.hh"
+
+#include "../file.hh"
+#include "../fixed_array.hh"
+#include "../scoped.hh"
+#include "../sized_iterator.hh"
+
+#include <algorithm>
+#include <iostream>
+#include <queue>
+#include <string>
+
+namespace util {
+namespace stream {
+
+struct NeverCombine {
+  template <class Compare> bool operator()(const void *, const void *, const Compare &) const {
+    return false;
+  }
+};
+
+// Manage the offsets of sorted blocks in a file.
+class Offsets {
+  public:
+    explicit Offsets(int fd) : log_(fd) {
+      Reset();
+    }
+
+    int File() const { return log_; }
+
+    void Append(uint64_t length) {
+      if (!length) return;
+      ++block_count_;
+      if (length == cur_.length) {
+        ++cur_.run;
+        return;
+      }
+      WriteOrThrow(log_, &cur_, sizeof(Entry));
+      cur_.length = length;
+      cur_.run = 1;
+    }
+
+    void FinishedAppending() {
+      WriteOrThrow(log_, &cur_, sizeof(Entry));
+      SeekOrThrow(log_, sizeof(Entry)); // Skip 0,0 at beginning.
+      cur_.run = 0;
+      if (block_count_) {
+        ReadOrThrow(log_, &cur_, sizeof(Entry));
+        assert(cur_.length);
+        assert(cur_.run);
+      }
+    }
+
+    uint64_t RemainingBlocks() const { return block_count_; }
+
+    uint64_t TotalOffset() const { return output_sum_; }
+
+    uint64_t PeekSize() const {
+      return cur_.length;
+    }
+
+    uint64_t NextSize() {
+      assert(block_count_);
+      uint64_t ret = cur_.length;
+      output_sum_ += ret;
+
+      --cur_.run;
+      --block_count_;
+      if (!cur_.run && block_count_) {
+        ReadOrThrow(log_, &cur_, sizeof(Entry));
+        assert(cur_.length);
+        assert(cur_.run);
+      }
+      return ret;
+    }
+
+    void Reset() {
+      SeekOrThrow(log_, 0);
+      ResizeOrThrow(log_, 0);
+      cur_.length = 0;
+      cur_.run = 0;
+      block_count_ = 0;
+      output_sum_ = 0;
+    }
+
+  private:
+    int log_;
+
+    struct Entry {
+      uint64_t length;
+      uint64_t run;
+    };
+    Entry cur_;
+
+    uint64_t block_count_;
+
+    uint64_t output_sum_;
+};
+
+// A priority queue of entries backed by file buffers
+template <class Compare> class MergeQueue {
+  public:
+    MergeQueue(int fd, std::size_t buffer_size, std::size_t entry_size, const Compare &compare)
+      : queue_(Greater(compare)), in_(fd), buffer_size_(buffer_size), entry_size_(entry_size) {}
+
+    void Push(void *base, uint64_t offset, uint64_t amount) {
+      queue_.push(Entry(base, in_, offset, amount, buffer_size_));
+    }
+
+    const void *Top() const {
+      return queue_.top().Current();
+    }
+
+    void Pop() {
+      Entry top(queue_.top());
+      queue_.pop();
+      if (top.Increment(in_, buffer_size_, entry_size_))
+        queue_.push(top);
+    }
+
+    std::size_t Size() const {
+      return queue_.size();
+    }
+
+    bool Empty() const {
+      return queue_.empty();
+    }
+
+  private:
+    // Priority queue contains these entries.
+    class Entry {
+      public:
+        Entry() {}
+
+        Entry(void *base, int fd, uint64_t offset, uint64_t amount, std::size_t buf_size) {
+          offset_ = offset;
+          remaining_ = amount;
+          buffer_end_ = static_cast<uint8_t*>(base) + buf_size;
+          Read(fd, buf_size);
+        }
+
+        bool Increment(int fd, std::size_t buf_size, std::size_t entry_size) {
+          current_ += entry_size;
+          if (current_ != buffer_end_) return true;
+          return Read(fd, buf_size);
+        }
+
+        const void *Current() const { return current_; }
+
+      private:
+        bool Read(int fd, std::size_t buf_size) {
+          current_ = buffer_end_ - buf_size;
+          std::size_t amount;
+          if (static_cast<uint64_t>(buf_size) < remaining_) {
+            amount = buf_size;
+          } else if (!remaining_) {
+            return false;
+          } else {
+            amount = remaining_;
+            buffer_end_ = current_ + remaining_;
+          }
+          ErsatzPRead(fd, current_, amount, offset_);
+          // Try to free the space, but don't be disappointed if we can't.
+          try {
+            HolePunch(fd, offset_, amount);
+          } catch (const util::Exception &) {}
+          offset_ += amount;
+          assert(current_ <= buffer_end_);
+          remaining_ -= amount;
+          return true;
+        }
+
+        // Buffer
+        uint8_t *current_, *buffer_end_;
+        // File
+        uint64_t remaining_, offset_;
+    };
+
+    // Wrapper comparison function for queue entries.
+    class Greater : public std::binary_function<const Entry &, const Entry &, bool> {
+      public:
+        explicit Greater(const Compare &compare) : compare_(compare) {}
+
+        bool operator()(const Entry &first, const Entry &second) const {
+          return compare_(second.Current(), first.Current());
+        }
+
+      private:
+        const Compare compare_;
+    };
+
+    typedef std::priority_queue<Entry, std::vector<Entry>, Greater> Queue;
+    Queue queue_;
+
+    const int in_;
+    const std::size_t buffer_size_;
+    const std::size_t entry_size_;
+};
+
+/* A worker object that merges.  If the number of pieces to merge exceeds the
+ * arity, it outputs multiple sorted blocks, recording to out_offsets.
+ * However, users will only every see a single sorted block out output because
+ * Sort::Sorted insures the arity is higher than the number of pieces before
+ * returning this.
+ */
+template <class Compare, class Combine> class MergingReader {
+  public:
+    MergingReader(int in, Offsets *in_offsets, Offsets *out_offsets, std::size_t buffer_size, std::size_t total_memory, const Compare &compare, const Combine &combine) :
+        compare_(compare), combine_(combine),
+        in_(in),
+        in_offsets_(in_offsets), out_offsets_(out_offsets),
+        buffer_size_(buffer_size), total_memory_(total_memory) {}
+
+    void Run(const ChainPosition &position) {
+      Run(position, false);
+    }
+
+    void Run(const ChainPosition &position, bool assert_one) {
+      // Special case: nothing to read.
+      if (!in_offsets_->RemainingBlocks()) {
+        Link l(position);
+        l.Poison();
+        return;
+      }
+      // If there's just one entry, just read.
+      if (in_offsets_->RemainingBlocks() == 1) {
+        // Sequencing is important.
+        uint64_t offset = in_offsets_->TotalOffset();
+        uint64_t amount = in_offsets_->NextSize();
+        ReadSingle(offset, amount, position);
+        if (out_offsets_) out_offsets_->Append(amount);
+        return;
+      }
+
+      Stream str(position);
+      scoped_malloc buffer(MallocOrThrow(total_memory_));
+      uint8_t *const buffer_end = static_cast<uint8_t*>(buffer.get()) + total_memory_;
+
+      const std::size_t entry_size = position.GetChain().EntrySize();
+
+      while (in_offsets_->RemainingBlocks()) {
+        // Use bigger buffers if there's less remaining.
+        uint64_t per_buffer = static_cast<uint64_t>(std::max<std::size_t>(
+            buffer_size_,
+            static_cast<std::size_t>((static_cast<uint64_t>(total_memory_) / in_offsets_->RemainingBlocks()))));
+        per_buffer -= per_buffer % entry_size;
+        assert(per_buffer);
+
+        // Populate queue.
+        MergeQueue<Compare> queue(in_, per_buffer, entry_size, compare_);
+        for (uint8_t *buf = static_cast<uint8_t*>(buffer.get());
+            in_offsets_->RemainingBlocks() && (buf + std::min(per_buffer, in_offsets_->PeekSize()) <= buffer_end);) {
+          uint64_t offset = in_offsets_->TotalOffset();
+          uint64_t size = in_offsets_->NextSize();
+          queue.Push(buf, offset, size);
+          buf += static_cast<std::size_t>(std::min<uint64_t>(size, per_buffer));
+        }
+        // This shouldn't happen but it's probably better to die than loop indefinitely.
+        if (queue.Size() < 2 && in_offsets_->RemainingBlocks()) {
+          std::cerr << "Bug in sort implementation: not merging at least two stripes." << std::endl;
+          abort();
+        }
+        if (assert_one && in_offsets_->RemainingBlocks()) {
+          std::cerr << "Bug in sort implementation: should only be one merge group for lazy sort" << std::endl;
+          abort();
+        }
+
+        uint64_t written = 0;
+        // Merge including combiner support.
+        memcpy(str.Get(), queue.Top(), entry_size);
+        for (queue.Pop(); !queue.Empty(); queue.Pop()) {
+          if (!combine_(str.Get(), queue.Top(), compare_)) {
+            ++written; ++str;
+            memcpy(str.Get(), queue.Top(), entry_size);
+          }
+        }
+        ++written; ++str;
+        if (out_offsets_)
+          out_offsets_->Append(written * entry_size);
+      }
+      str.Poison();
+    }
+
+  private:
+    void ReadSingle(uint64_t offset, const uint64_t size, const ChainPosition &position) {
+      // Special case: only one to read.
+      const uint64_t end = offset + size;
+      const uint64_t block_size = position.GetChain().BlockSize();
+      Link l(position);
+      for (; offset + block_size < end; ++l, offset += block_size) {
+        ErsatzPRead(in_, l->Get(), block_size, offset);
+        l->SetValidSize(block_size);
+      }
+      ErsatzPRead(in_, l->Get(), end - offset, offset);
+      l->SetValidSize(end - offset);
+      (++l).Poison();
+      return;
+    }
+
+    Compare compare_;
+    Combine combine_;
+
+    int in_;
+
+  protected:
+    Offsets *in_offsets_;
+
+  private:
+    Offsets *out_offsets_;
+
+    std::size_t buffer_size_;
+    std::size_t total_memory_;
+};
+
+// The lazy step owns the remaining files.  This keeps track of them.
+template <class Compare, class Combine> class OwningMergingReader : public MergingReader<Compare, Combine> {
+  private:
+    typedef MergingReader<Compare, Combine> P;
+  public:
+    OwningMergingReader(int data, const Offsets &offsets, std::size_t buffer, std::size_t lazy, const Compare &compare, const Combine &combine)
+      : P(data, NULL, NULL, buffer, lazy, compare, combine),
+        data_(data),
+        offsets_(offsets) {}
+
+    void Run(const ChainPosition &position) {
+      P::in_offsets_ = &offsets_;
+      scoped_fd data(data_);
+      scoped_fd offsets_file(offsets_.File());
+      P::Run(position, true);
+    }
+
+  private:
+    int data_;
+    Offsets offsets_;
+};
+
+// Don't use this directly.  Worker that sorts blocks.
+template <class Compare> class BlockSorter {
+  public:
+    BlockSorter(Offsets &offsets, const Compare &compare) :
+      offsets_(&offsets), compare_(compare) {}
+
+    void Run(const ChainPosition &position) {
+      const std::size_t entry_size = position.GetChain().EntrySize();
+      for (Link link(position); link; ++link) {
+        // Record the size of each block in a separate file.
+        offsets_->Append(link->ValidSize());
+        void *end = static_cast<uint8_t*>(link->Get()) + link->ValidSize();
+        SizedSort(link->Get(), end, entry_size, compare_);
+      }
+      offsets_->FinishedAppending();
+    }
+
+  private:
+    Offsets *offsets_;
+    Compare compare_;
+};
+
+class BadSortConfig : public Exception {
+  public:
+    BadSortConfig() throw() {}
+    ~BadSortConfig() throw() {}
+};
+
+/** Sort */
+template <class Compare, class Combine = NeverCombine> class Sort {
+  public:
+    /** Constructs an object capable of sorting */
+    Sort(Chain &in, const SortConfig &config, const Compare &compare = Compare(), const Combine &combine = Combine())
+      : config_(config),
+        data_(MakeTemp(config.temp_prefix)),
+        offsets_file_(MakeTemp(config.temp_prefix)), offsets_(offsets_file_.get()),
+        compare_(compare), combine_(combine),
+        entry_size_(in.EntrySize()) {
+      UTIL_THROW_IF(!entry_size_, BadSortConfig, "Sorting entries of size 0");
+      // Make buffer_size a multiple of the entry_size.
+      config_.buffer_size -= config_.buffer_size % entry_size_;
+      UTIL_THROW_IF(!config_.buffer_size, BadSortConfig, "Sort buffer too small");
+      UTIL_THROW_IF(config_.total_memory < config_.buffer_size * 4, BadSortConfig, "Sorting memory " << config_.total_memory << " is too small for four buffers (two read and two write).");
+      in >> BlockSorter<Compare>(offsets_, compare_) >> WriteAndRecycle(data_.get());
+    }
+
+    uint64_t Size() const {
+      return SizeOrThrow(data_.get());
+    }
+
+    // Do merge sort, terminating when lazy merge could be done with the
+    // specified memory.  Return the minimum memory necessary to do lazy merge.
+    std::size_t Merge(std::size_t lazy_memory) {
+      if (offsets_.RemainingBlocks() <= 1) return 0;
+      const uint64_t lazy_arity = std::max<uint64_t>(1, lazy_memory / config_.buffer_size);
+      uint64_t size = Size();
+      /* No overflow because
+       * offsets_.RemainingBlocks() * config_.buffer_size <= lazy_memory ||
+       * size < lazy_memory
+       */
+      if (offsets_.RemainingBlocks() <= lazy_arity || size <= static_cast<uint64_t>(lazy_memory))
+        return std::min<std::size_t>(size, offsets_.RemainingBlocks() * config_.buffer_size);
+
+      scoped_fd data2(MakeTemp(config_.temp_prefix));
+      int fd_in = data_.get(), fd_out = data2.get();
+      scoped_fd offsets2_file(MakeTemp(config_.temp_prefix));
+      Offsets offsets2(offsets2_file.get());
+      Offsets *offsets_in = &offsets_, *offsets_out = &offsets2;
+
+      // Double buffered writing.
+      ChainConfig chain_config;
+      chain_config.entry_size = entry_size_;
+      chain_config.block_count = 2;
+      chain_config.total_memory = config_.buffer_size * 2;
+      Chain chain(chain_config);
+
+      while (offsets_in->RemainingBlocks() > lazy_arity) {
+        if (size <= static_cast<uint64_t>(lazy_memory)) break;
+        std::size_t reading_memory = config_.total_memory - 2 * config_.buffer_size;
+        if (size < static_cast<uint64_t>(reading_memory)) {
+          reading_memory = static_cast<std::size_t>(size);
+        }
+        SeekOrThrow(fd_in, 0);
+        chain >>
+          MergingReader<Compare, Combine>(
+              fd_in,
+              offsets_in, offsets_out,
+              config_.buffer_size,
+              reading_memory,
+              compare_, combine_) >>
+          WriteAndRecycle(fd_out);
+        chain.Wait();
+        offsets_out->FinishedAppending();
+        ResizeOrThrow(fd_in, 0);
+        offsets_in->Reset();
+        std::swap(fd_in, fd_out);
+        std::swap(offsets_in, offsets_out);
+        size = SizeOrThrow(fd_in);
+      }
+
+      SeekOrThrow(fd_in, 0);
+      if (fd_in == data2.get()) {
+        data_.reset(data2.release());
+        offsets_file_.reset(offsets2_file.release());
+        offsets_ = offsets2;
+      }
+      if (offsets_.RemainingBlocks() <= 1) return 0;
+      // No overflow because the while loop exited.
+      return std::min(size, offsets_.RemainingBlocks() * static_cast<uint64_t>(config_.buffer_size));
+    }
+
+    // Output to chain, using this amount of memory, maximum, for lazy merge
+    // sort.
+    void Output(Chain &out, std::size_t lazy_memory) {
+      Merge(lazy_memory);
+      out.SetProgressTarget(Size());
+      out >> OwningMergingReader<Compare, Combine>(data_.get(), offsets_, config_.buffer_size, lazy_memory, compare_, combine_);
+      data_.release();
+      offsets_file_.release();
+    }
+
+    /* If a pipeline step is reading sorted input and writing to a different
+     * sort order, then there's a trade-off between using RAM to read lazily
+     * (avoiding copying the file) and using RAM to increase block size and,
+     * therefore, decrease the number of merge sort passes in the next
+     * iteration.
+     *
+     * Merge sort takes log_{arity}(pieces) passes.  Thus, each time the chain
+     * block size is multiplied by arity, the number of output passes decreases
+     * by one.  Up to a constant, then, log_{arity}(chain) is the number of
+     * passes saved.  Chain simply divides the memory evenly over all blocks.
+     *
+     * Lazy sort saves this many passes (up to a constant)
+     *   log_{arity}((memory-lazy)/block_count) + 1
+     * Non-lazy sort saves this many passes (up to the same constant):
+     *   log_{arity}(memory/block_count)
+     * Add log_{arity}(block_count) to both:
+     *   log_{arity}(memory-lazy) + 1 versus log_{arity}(memory)
+     * Take arity to the power of both sizes (arity > 1)
+     *   (memory - lazy)*arity versus memory
+     * Solve for lazy
+     *   lazy = memory * (arity - 1) / arity
+     */
+    std::size_t DefaultLazy() {
+      float arity = static_cast<float>(config_.total_memory / config_.buffer_size);
+      return static_cast<std::size_t>(static_cast<float>(config_.total_memory) * (arity - 1.0) / arity);
+    }
+
+    // Same as Output with default lazy memory setting.
+    void Output(Chain &out) {
+      Output(out, DefaultLazy());
+    }
+
+    // Completely merge sort and transfer ownership to the caller.
+    int StealCompleted() {
+      // Merge all the way.
+      Merge(0);
+      SeekOrThrow(data_.get(), 0);
+      offsets_file_.reset();
+      return data_.release();
+    }
+
+  private:
+    SortConfig config_;
+
+    scoped_fd data_;
+
+    scoped_fd offsets_file_;
+    Offsets offsets_;
+
+    const Compare compare_;
+    const Combine combine_;
+    const std::size_t entry_size_;
+};
+
+// returns bytes to be read on demand.
+template <class Compare, class Combine> uint64_t BlockingSort(Chain &chain, const SortConfig &config, const Compare &compare = Compare(), const Combine &combine = NeverCombine()) {
+  Sort<Compare, Combine> sorter(chain, config, compare, combine);
+  chain.Wait(true);
+  uint64_t size = sorter.Size();
+  sorter.Output(chain);
+  return size;
+}
+
+/**
+ * Represents an @ref util::FixedArray "array" capable of storing @ref util::stream::Sort "Sort" objects.
+ *
+ * In the anticipated use case, an instance of this class will maintain one @ref util::stream::Sort "Sort" object
+ * for each n-gram order (ranging from 1 up to the maximum n-gram order being processed).
+ * Use in this manner would enable the n-grams each n-gram order to be sorted, in parallel.
+ *
+ * @tparam Compare An @ref Comparator "ngram comparator" to use during sorting.
+ */
+template <class Compare, class Combine = NeverCombine> class Sorts : public FixedArray<Sort<Compare, Combine> > {
+  private:
+    typedef Sort<Compare, Combine> S;
+    typedef FixedArray<S> P;
+
+  public:
+    /**
+     * Constructs, but does not initialize.
+     *
+     * @ref util::FixedArray::Init() "Init" must be called before use.
+     *
+     * @see util::FixedArray::Init()
+     */
+    Sorts() {}
+
+    /**
+     * Constructs an @ref util::FixedArray "array" capable of storing a fixed number of @ref util::stream::Sort "Sort" objects.
+     *
+     * @param number The maximum number of @ref util::stream::Sort "sorters" that can be held by this @ref util::FixedArray "array"
+     * @see util::FixedArray::FixedArray()
+     */
+    explicit Sorts(std::size_t number) : FixedArray<Sort<Compare, Combine> >(number) {}
+
+    /**
+     * Constructs a new @ref util::stream::Sort "Sort" object which is stored in this @ref util::FixedArray "array".
+     *
+     * The new @ref util::stream::Sort "Sort" object is constructed using the provided @ref util::stream::SortConfig "SortConfig" and @ref Comparator "ngram   comparator";
+     * once constructed, a new worker @ref util::stream::Thread "thread" (owned by the @ref util::stream::Chain "chain") will sort the n-gram data stored
+     * in the @ref util::stream::Block "blocks" of the provided @ref util::stream::Chain "chain".
+     *
+     * @see util::stream::Sort::Sort()
+     * @see util::stream::Chain::operator>>()
+     */
+    void push_back(util::stream::Chain &chain, const util::stream::SortConfig &config, const Compare &compare = Compare(), const Combine &combine = Combine()) {
+      new (P::end()) S(chain, config, compare, combine); // use "placement new" syntax to initalize S in an already-allocated memory location
+      P::Constructed();
+    }
+};
+
+} // namespace stream
+} // namespace util
+
+#endif // UTIL_STREAM_SORT_H

cpp/thirdpart/kenlm/util/stream/sort_test.cc

+#include "sort.hh"
+
+#define BOOST_TEST_MODULE SortTest
+#include <boost/test/unit_test.hpp>
+
+#include <algorithm>
+
+#include <unistd.h>
+
+namespace util { namespace stream { namespace {
+
+struct CompareUInt64 : public std::binary_function<const void *, const void *, bool> {
+  bool operator()(const void *first, const void *second) const {
+    return *static_cast<const uint64_t*>(first) < *reinterpret_cast<const uint64_t*>(second);
+  }
+};
+
+const uint64_t kSize = 100000;
+
+struct Putter {
+  Putter(std::vector<uint64_t> &shuffled) : shuffled_(shuffled) {}
+
+  void Run(const ChainPosition &position) {
+    Stream put_shuffled(position);
+    for (uint64_t i = 0; i < shuffled_.size(); ++i, ++put_shuffled) {
+      *static_cast<uint64_t*>(put_shuffled.Get()) = shuffled_[i];
+    }
+    put_shuffled.Poison();
+  }
+  std::vector<uint64_t> &shuffled_;
+};
+
+BOOST_AUTO_TEST_CASE(FromShuffled) {
+  std::vector<uint64_t> shuffled;
+  shuffled.reserve(kSize);
+  for (uint64_t i = 0; i < kSize; ++i) {
+    shuffled.push_back(i);
+  }
+  std::random_shuffle(shuffled.begin(), shuffled.end());
+
+  ChainConfig config;
+  config.entry_size = 8;
+  config.total_memory = 800;
+  config.block_count = 3;
+
+  SortConfig merge_config;
+  merge_config.temp_prefix = "sort_test_temp";
+  merge_config.buffer_size = 800;
+  merge_config.total_memory = 3300;
+
+  Chain chain(config);
+  chain >> Putter(shuffled);
+  BlockingSort(chain, merge_config, CompareUInt64(), NeverCombine());
+  Stream sorted;
+  chain >> sorted >> kRecycle;
+  for (uint64_t i = 0; i < kSize; ++i, ++sorted) {
+    BOOST_CHECK_EQUAL(i, *static_cast<const uint64_t*>(sorted.Get()));
+  }
+  BOOST_CHECK(!sorted);
+}
+
+}}} // namespaces

cpp/thirdpart/kenlm/util/stream/stream.hh

+#ifndef UTIL_STREAM_STREAM_H
+#define UTIL_STREAM_STREAM_H
+
+#include "chain.hh"
+
+#include <boost/noncopyable.hpp>
+
+#include <cassert>
+#include <stdint.h>
+
+namespace util {
+namespace stream {
+
+class Stream : boost::noncopyable {
+  public:
+    Stream() : current_(NULL), end_(NULL) {}
+
+    void Init(const ChainPosition &position) {
+      entry_size_ = position.GetChain().EntrySize();
+      block_size_ = position.GetChain().BlockSize();
+      block_it_.Init(position);
+      StartBlock();
+    }
+
+    explicit Stream(const ChainPosition &position) {
+      Init(position);
+    }
+
+    operator bool() const { return current_ != NULL; }
+    bool operator!() const { return current_ == NULL; }
+
+    const void *Get() const { return current_; }
+    void *Get() { return current_; }
+
+    void Poison() {
+      block_it_->SetValidSize(current_ - static_cast<uint8_t*>(block_it_->Get()));
+      ++block_it_;
+      block_it_.Poison();
+    }
+
+    Stream &operator++() {
+      assert(*this);
+      assert(current_ < end_);
+      current_ += entry_size_;
+      if (current_ == end_) {
+        ++block_it_;
+        StartBlock();
+      }
+      return *this;
+    }
+
+  private:
+    void StartBlock() {
+      for (; block_it_ && !block_it_->ValidSize(); ++block_it_) {}
+      current_ = static_cast<uint8_t*>(block_it_->Get());
+      end_ = current_ + block_it_->ValidSize();
+    }
+
+    // The following are pointers to raw memory
+    // current_ is the current record
+    // end_ is the end of the block (so we know when to move to the next block)
+    uint8_t *current_, *end_;
+
+    std::size_t entry_size_;
+    std::size_t block_size_;
+
+    Link block_it_;
+};
+
+inline Chain &operator>>(Chain &chain, Stream &stream) {
+  stream.Init(chain.Add());
+  return chain;
+}
+
+} // namespace stream
+} // namespace util
+#endif // UTIL_STREAM_STREAM_H

cpp/thirdpart/kenlm/util/stream/stream_test.cc

+#include "io.hh"
+
+#include "stream.hh"
+#include "../file.hh"
+
+#define BOOST_TEST_MODULE StreamTest
+#include <boost/test/unit_test.hpp>
+
+#include <unistd.h>
+
+namespace util { namespace stream { namespace {
+
+BOOST_AUTO_TEST_CASE(StreamTest) {
+  scoped_fd in(MakeTemp("io_test_temp"));
+  for (uint64_t i = 0; i < 100000; ++i) {
+    WriteOrThrow(in.get(), &i, sizeof(uint64_t));
+  }
+  SeekOrThrow(in.get(), 0);
+
+  ChainConfig config;
+  config.entry_size = 8;
+  config.total_memory = 100;
+  config.block_count = 12;
+
+  Stream s;
+  Chain chain(config);
+  chain >> Read(in.get()) >> s >> kRecycle;
+  uint64_t i = 0;
+  for (; s; ++s, ++i) {
+    BOOST_CHECK_EQUAL(i, *static_cast<const uint64_t*>(s.Get()));
+  }
+  BOOST_CHECK_EQUAL(100000ULL, i);
+}
+
+}}} // namespaces

cpp/thirdpart/kenlm/util/stream/typed_stream.hh

+#ifndef UTIL_STREAM_TYPED_STREAM_H
+#define UTIL_STREAM_TYPED_STREAM_H
+// A typed wrapper to Stream for POD types.
+
+#include "stream.hh"
+
+namespace util { namespace stream {
+
+template <class T> class TypedStream : public Stream {
+  public:
+    // After using the default constructor, call Init (in the parent class)
+    TypedStream() {}
+
+    explicit TypedStream(const ChainPosition &position) : Stream(position) {}
+
+    const T *operator->() const { return static_cast<const T*>(Get()); }
+    T *operator->() { return static_cast<T*>(Get()); }
+
+    const T &operator*() const { return *static_cast<const T*>(Get()); }
+    T &operator*() { return *static_cast<T*>(Get()); }
+};
+
+}} // namespaces
+
+#endif // UTIL_STREAM_TYPED_STREAM_H

cpp/thirdpart/kenlm/util/string_piece.cc

+// Copyright 2004 The RE2 Authors.  All Rights Reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in string_piece.hh.
+
+#include "string_piece.hh"
+
+#include <algorithm>
+#include <climits>
+
+#ifndef HAVE_ICU
+
+typedef StringPiece::size_type size_type;
+
+void StringPiece::CopyToString(std::string* target) const {
+  target->assign(ptr_, length_);
+}
+
+size_type StringPiece::find(const StringPiece& s, size_type pos) const {
+  // Not sure why length_ < 0 was here since it's std::size_t.
+  if (/*length_ < 0 || */pos > static_cast<size_type>(length_))
+    return npos;
+
+  const char* result = std::search(ptr_ + pos, ptr_ + length_,
+                                   s.ptr_, s.ptr_ + s.length_);
+  const size_type xpos = result - ptr_;
+  return xpos + s.length_ <= length_ ? xpos : npos;
+}
+
+size_type StringPiece::find(char c, size_type pos) const {
+  if (length_ <= 0 || pos >= static_cast<size_type>(length_)) {
+    return npos;
+  }
+  const char* result = std::find(ptr_ + pos, ptr_ + length_, c);
+  return result != ptr_ + length_ ? result - ptr_ : npos;
+}
+
+size_type StringPiece::rfind(const StringPiece& s, size_type pos) const {
+  if (length_ < s.length_) return npos;
+  const size_t ulen = length_;
+  if (s.length_ == 0) return std::min(ulen, pos);
+
+  const char* last = ptr_ + std::min(ulen - s.length_, pos) + s.length_;
+  const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_);
+  return result != last ? result - ptr_ : npos;
+}
+
+size_type StringPiece::rfind(char c, size_type pos) const {
+  if (length_ <= 0) return npos;
+  for (int i = std::min(pos, static_cast<size_type>(length_ - 1));
+       i >= 0; --i) {
+    if (ptr_[i] == c) {
+      return i;
+    }
+  }
+  return npos;
+}
+
+// For each character in characters_wanted, sets the index corresponding
+// to the ASCII code of that character to 1 in table.  This is used by
+// the find_.*_of methods below to tell whether or not a character is in
+// the lookup table in constant time.
+// The argument `table' must be an array that is large enough to hold all
+// the possible values of an unsigned char.  Thus it should be be declared
+// as follows:
+//   bool table[UCHAR_MAX + 1]
+static inline void BuildLookupTable(const StringPiece& characters_wanted,
+                                    bool* table) {
+  const size_type length = characters_wanted.length();
+  const char* const data = characters_wanted.data();
+  for (size_type i = 0; i < length; ++i) {
+    table[static_cast<unsigned char>(data[i])] = true;
+  }
+}
+
+size_type StringPiece::find_first_of(const StringPiece& s,
+                                     size_type pos) const {
+  if (length_ == 0 || s.length_ == 0)
+    return npos;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.length_ == 1)
+    return find_first_of(s.ptr_[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (size_type i = pos; i < length_; ++i) {
+    if (lookup[static_cast<unsigned char>(ptr_[i])]) {
+      return i;
+    }
+  }
+  return npos;
+}
+
+size_type StringPiece::find_first_not_of(const StringPiece& s,
+                                         size_type pos) const {
+  if (length_ == 0)
+    return npos;
+
+  if (s.length_ == 0)
+    return 0;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.length_ == 1)
+    return find_first_not_of(s.ptr_[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (size_type i = pos; i < length_; ++i) {
+    if (!lookup[static_cast<unsigned char>(ptr_[i])]) {
+      return i;
+    }
+  }
+  return npos;
+}
+
+size_type StringPiece::find_first_not_of(char c, size_type pos) const {
+  if (length_ == 0)
+    return npos;
+
+  for (; pos < length_; ++pos) {
+    if (ptr_[pos] != c) {
+      return pos;
+    }
+  }
+  return npos;
+}
+
+size_type StringPiece::find_last_of(const StringPiece& s, size_type pos) const {
+  if (length_ == 0 || s.length_ == 0)
+    return npos;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.length_ == 1)
+    return find_last_of(s.ptr_[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (size_type i = std::min(pos, length_ - 1); ; --i) {
+    if (lookup[static_cast<unsigned char>(ptr_[i])])
+      return i;
+    if (i == 0)
+      break;
+  }
+  return npos;
+}
+
+size_type StringPiece::find_last_not_of(const StringPiece& s,
+                                        size_type pos) const {
+  if (length_ == 0)
+    return npos;
+
+  size_type i = std::min(pos, length_ - 1);
+  if (s.length_ == 0)
+    return i;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.length_ == 1)
+    return find_last_not_of(s.ptr_[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (; ; --i) {
+    if (!lookup[static_cast<unsigned char>(ptr_[i])])
+      return i;
+    if (i == 0)
+      break;
+  }
+  return npos;
+}
+
+size_type StringPiece::find_last_not_of(char c, size_type pos) const {
+  if (length_ == 0)
+    return npos;
+
+  for (size_type i = std::min(pos, length_ - 1); ; --i) {
+    if (ptr_[i] != c)
+      return i;
+    if (i == 0)
+      break;
+  }
+  return npos;
+}
+
+StringPiece StringPiece::substr(size_type pos, size_type n) const {
+  if (pos > length_) pos = length_;
+  if (n > length_ - pos) n = length_ - pos;
+  return StringPiece(ptr_ + pos, n);
+}
+
+const size_type StringPiece::npos = size_type(-1);
+
+#endif // !HAVE_ICU

cpp/thirdpart/kenlm/util/string_piece.hh

+/* If you use ICU in your program, then compile with -DHAVE_ICU -licui18n.  If
+ * you don't use ICU, then this will use the Google implementation from Chrome.
+ * This has been modified from the original version to let you choose.
+ */
+
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Copied from strings/stringpiece.h with modifications
+//
+// A string-like object that points to a sized piece of memory.
+//
+// Functions or methods may use const StringPiece& parameters to accept either
+// a "const char*" or a "string" value that will be implicitly converted to
+// a StringPiece.  The implicit conversion means that it is often appropriate
+// to include this .h file in other files rather than forward-declaring
+// StringPiece as would be appropriate for most other Google classes.
+//
+// Systematic usage of StringPiece is encouraged as it will reduce unnecessary
+// conversions from "const char*" to "string" and back again.
+//
+
+#ifndef UTIL_STRING_PIECE_H
+#define UTIL_STRING_PIECE_H
+
+#include "have.hh"
+
+#include <cstring>
+#include <iosfwd>
+#include <ostream>
+
+#ifdef HAVE_ICU
+#include <unicode/stringpiece.h>
+#include <unicode/uversion.h>
+
+// Old versions of ICU don't define operator== and operator!=.
+#if (U_ICU_VERSION_MAJOR_NUM < 4) || ((U_ICU_VERSION_MAJOR_NUM == 4) && (U_ICU_VERSION_MINOR_NUM < 4))
+#warning You are using an old version of ICU.  Consider upgrading to ICU >= 4.6.
+inline bool operator==(const StringPiece& x, const StringPiece& y) {
+  if (x.size() != y.size())
+    return false;
+
+  return std::memcmp(x.data(), y.data(), x.size()) == 0;
+}
+
+inline bool operator!=(const StringPiece& x, const StringPiece& y) {
+  return !(x == y);
+}
+#endif // old version of ICU
+
+U_NAMESPACE_BEGIN
+
+inline bool starts_with(const StringPiece& longer, const StringPiece& prefix) {
+  int longersize = longer.size(), prefixsize = prefix.size();
+  return longersize >= prefixsize && std::memcmp(longer.data(), prefix.data(), prefixsize) == 0;
+}
+
+#else
+
+#include <algorithm>
+#include <cstddef>
+#include <string>
+#include <cstring>
+
+#ifdef WIN32
+#undef max
+#undef min
+#endif
+
+class StringPiece {
+ public:
+  typedef size_t size_type;
+
+ private:
+  const char*   ptr_;
+  size_type     length_;
+
+ public:
+  // We provide non-explicit singleton constructors so users can pass
+  // in a "const char*" or a "string" wherever a "StringPiece" is
+  // expected.
+  StringPiece() : ptr_(NULL), length_(0) { }
+  StringPiece(const char* str)
+    : ptr_(str), length_((str == NULL) ? 0 : strlen(str)) { }
+  StringPiece(const std::string& str)
+    : ptr_(str.data()), length_(str.size()) { }
+  StringPiece(const char* offset, size_type len)
+    : ptr_(offset), length_(len) { }
+
+  // data() may return a pointer to a buffer with embedded NULs, and the
+  // returned buffer may or may not be null terminated.  Therefore it is
+  // typically a mistake to pass data() to a routine that expects a NUL
+  // terminated string.
+  const char* data() const { return ptr_; }
+  size_type size() const { return length_; }
+  size_type length() const { return length_; }
+  bool empty() const { return length_ == 0; }
+
+  void clear() { ptr_ = NULL; length_ = 0; }
+  void set(const char* data, size_type len) { ptr_ = data; length_ = len; }
+  void set(const char* str) {
+    ptr_ = str;
+    length_ = str ? strlen(str) : 0;
+  }
+  void set(const void* data, size_type len) {
+    ptr_ = reinterpret_cast<const char*>(data);
+    length_ = len;
+  }
+
+  char operator[](size_type i) const { return ptr_[i]; }
+
+  void remove_prefix(size_type n) {
+    ptr_ += n;
+    length_ -= n;
+  }
+
+  void remove_suffix(size_type n) {
+    length_ -= n;
+  }
+
+  int compare(const StringPiece& x) const {
+    int r = wordmemcmp(ptr_, x.ptr_, std::min(length_, x.length_));
+    if (r == 0) {
+      if (length_ < x.length_) r = -1;
+      else if (length_ > x.length_) r = +1;
+    }
+    return r;
+  }
+
+  std::string as_string() const {
+    // std::string doesn't like to take a NULL pointer even with a 0 size.
+    return std::string(!empty() ? data() : "", size());
+  }
+
+  void CopyToString(std::string* target) const;
+  void AppendToString(std::string* target) const;
+
+  // Does "this" start with "x"
+  bool starts_with(const StringPiece& x) const {
+    return ((length_ >= x.length_) &&
+            (wordmemcmp(ptr_, x.ptr_, x.length_) == 0));
+  }
+
+  // Does "this" end with "x"
+  bool ends_with(const StringPiece& x) const {
+    return ((length_ >= x.length_) &&
+            (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0));
+  }
+
+  // standard STL container boilerplate
+  typedef char value_type;
+  typedef const char* pointer;
+  typedef const char& reference;
+  typedef const char& const_reference;
+  typedef ptrdiff_t difference_type;
+  static const size_type npos;
+  typedef const char* const_iterator;
+  typedef const char* iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+  typedef std::reverse_iterator<iterator> reverse_iterator;
+  iterator begin() const { return ptr_; }
+  iterator end() const { return ptr_ + length_; }
+  const_reverse_iterator rbegin() const {
+    return const_reverse_iterator(ptr_ + length_);
+  }
+  const_reverse_iterator rend() const {
+    return const_reverse_iterator(ptr_);
+  }
+
+  size_type max_size() const { return length_; }
+  size_type capacity() const { return length_; }
+
+  size_type copy(char* buf, size_type n, size_type pos = 0) const;
+
+  size_type find(const StringPiece& s, size_type pos = 0) const;
+  size_type find(char c, size_type pos = 0) const;
+  size_type rfind(const StringPiece& s, size_type pos = npos) const;
+  size_type rfind(char c, size_type pos = npos) const;
+
+  size_type find_first_of(const StringPiece& s, size_type pos = 0) const;
+  size_type find_first_of(char c, size_type pos = 0) const {
+    return find(c, pos);
+  }
+  size_type find_first_not_of(const StringPiece& s, size_type pos = 0) const;
+  size_type find_first_not_of(char c, size_type pos = 0) const;
+  size_type find_last_of(const StringPiece& s, size_type pos = npos) const;
+  size_type find_last_of(char c, size_type pos = npos) const {
+    return rfind(c, pos);
+  }
+  size_type find_last_not_of(const StringPiece& s, size_type pos = npos) const;
+  size_type find_last_not_of(char c, size_type pos = npos) const;
+
+  StringPiece substr(size_type pos, size_type n = npos) const;
+
+  static int wordmemcmp(const char* p, const char* p2, size_type N) {
+    return std::memcmp(p, p2, N);
+  }
+};
+
+inline bool operator==(const StringPiece& x, const StringPiece& y) {
+  if (x.size() != y.size())
+    return false;
+
+  return std::memcmp(x.data(), y.data(), x.size()) == 0;
+}
+
+inline bool operator!=(const StringPiece& x, const StringPiece& y) {
+  return !(x == y);
+}
+
+inline bool starts_with(const StringPiece& longer, const StringPiece& prefix) {
+  return longer.starts_with(prefix);
+}
+
+#endif // HAVE_ICU undefined
+
+inline bool operator<(const StringPiece& x, const StringPiece& y) {
+  const int r = std::memcmp(x.data(), y.data(),
+                                       std::min(x.size(), y.size()));
+  return ((r < 0) || ((r == 0) && (x.size() < y.size())));
+}
+
+inline bool operator>(const StringPiece& x, const StringPiece& y) {
+  return y < x;
+}
+
+inline bool operator<=(const StringPiece& x, const StringPiece& y) {
+  return !(x > y);
+}
+
+inline bool operator>=(const StringPiece& x, const StringPiece& y) {
+  return !(x < y);
+}
+
+// allow StringPiece to be logged (needed for unit testing).
+inline std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
+  return o.write(piece.data(), static_cast<std::streamsize>(piece.size()));
+}
+
+#ifdef HAVE_ICU
+U_NAMESPACE_END
+using U_NAMESPACE_QUALIFIER StringPiece;
+#endif
+
+#endif  // UTIL_STRING_PIECE_H

cpp/thirdpart/kenlm/util/string_piece_hash.hh

+#ifndef UTIL_STRING_PIECE_HASH_H
+#define UTIL_STRING_PIECE_HASH_H
+
+#include "have.hh"
+#include "string_piece.hh"
+
+#include <boost/functional/hash.hpp>
+#include <boost/version.hpp>
+
+#ifdef HAVE_ICU
+U_NAMESPACE_BEGIN
+#endif
+
+inline size_t hash_value(const StringPiece &str) {
+  return boost::hash_range(str.data(), str.data() + str.length());
+}
+
+#ifdef HAVE_ICU
+U_NAMESPACE_END
+#endif
+
+/* Support for lookup of StringPiece in boost::unordered_map<std::string> */
+struct StringPieceCompatibleHash : public std::unary_function<const StringPiece &, size_t> {
+  size_t operator()(const StringPiece &str) const {
+    return hash_value(str);
+  }
+};
+
+struct StringPieceCompatibleEquals : public std::binary_function<const StringPiece &, const std::string &, bool> {
+  bool operator()(const StringPiece &first, const StringPiece &second) const {
+    return first == second;
+  }
+};
+template <class T> typename T::const_iterator FindStringPiece(const T &t, const StringPiece &key) {
+#if BOOST_VERSION < 104200
+  std::string temp(key.data(), key.size());
+  return t.find(temp);
+#else
+  return t.find(key, StringPieceCompatibleHash(), StringPieceCompatibleEquals());
+#endif
+}
+
+template <class T> typename T::iterator FindStringPiece(T &t, const StringPiece &key) {
+#if BOOST_VERSION < 104200
+  std::string temp(key.data(), key.size());
+  return t.find(temp);
+#else
+  return t.find(key, StringPieceCompatibleHash(), StringPieceCompatibleEquals());
+#endif
+}
+
+#endif // UTIL_STRING_PIECE_HASH_H

cpp/thirdpart/kenlm/util/string_stream.hh

+#ifndef UTIL_STRING_STREAM_H
+#define UTIL_STRING_STREAM_H
+
+#include "fake_ostream.hh"
+
+#include <cassert>
+#include <string>
+
+namespace util {
+
+class StringStream : public FakeOStream<StringStream> {
+  public:
+    StringStream() {}
+
+    StringStream &flush() { return *this; }
+
+    StringStream &write(const void *data, std::size_t length) {
+      out_.append(static_cast<const char*>(data), length);
+      return *this;
+    }
+
+    const std::string &str() const { return out_; }
+
+    void str(const std::string &val) { out_ = val; }
+
+    void swap(std::string &str) { std::swap(out_, str); }
+
+  protected:
+    friend class FakeOStream<StringStream>;
+    char *Ensure(std::size_t amount) {
+      std::size_t current = out_.size();
+      out_.resize(out_.size() + amount);
+      return &out_[current];
+    }
+
+    void AdvanceTo(char *to) {
+      assert(to <= &*out_.end());
+      assert(to >= &*out_.begin());
+      out_.resize(to - &*out_.begin());
+    }
+
+  private:
+    std::string out_;
+};
+
+} // namespace
+
+#endif // UTIL_STRING_STREAM_H