rocksdb/port/win/xpress_win.cc

//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#include "port/win/xpress_win.h"
#include <windows.h>

#include <cassert>
#include <memory>
#include <limits>
#include <iostream>

#ifdef XPRESS

// Put this under ifdef so windows systems w/o this
// can still build
#include <compressapi.h>

namespace rocksdb {
namespace port {
namespace xpress {

// Helpers
namespace {

auto CloseCompressorFun = [](void* h) {
  if (NULL != h) {
    ::CloseCompressor(reinterpret_cast<COMPRESSOR_HANDLE>(h));
  }
};

auto CloseDecompressorFun = [](void* h) {
  if (NULL != h) {
    ::CloseDecompressor(reinterpret_cast<DECOMPRESSOR_HANDLE>(h));
  }
};
}

bool Compress(const char* input, size_t length, std::string* output) {

  assert(input != nullptr);
  assert(output != nullptr);

  if (length == 0) {
    output->clear();
    return true;
  }

  COMPRESS_ALLOCATION_ROUTINES* allocRoutinesPtr = nullptr;

  COMPRESSOR_HANDLE compressor = NULL;

  BOOL success = CreateCompressor(
    COMPRESS_ALGORITHM_XPRESS, //  Compression Algorithm
    allocRoutinesPtr,       //  Optional allocation routine
    &compressor);              //  Handle

  if (!success) {
#ifdef _DEBUG
    std::cerr << "XPRESS: Failed to create Compressor LastError: " <<
      GetLastError() << std::endl;
#endif
    return false;
  }

  std::unique_ptr<void, decltype(CloseCompressorFun)>
    compressorGuard(compressor, CloseCompressorFun);

  SIZE_T compressedBufferSize = 0;

  //  Query compressed buffer size.
  success = ::Compress(
    compressor,                 //  Compressor Handle
    const_cast<char*>(input),   //  Input buffer
    length,                     //  Uncompressed data size
    NULL,                       //  Compressed Buffer
    0,                          //  Compressed Buffer size
    &compressedBufferSize);     //  Compressed Data size

  if (!success) {

    auto lastError = GetLastError();

    if (lastError != ERROR_INSUFFICIENT_BUFFER) {
#ifdef _DEBUG
      std::cerr <<
        "XPRESS: Failed to estimate compressed buffer size LastError " <<
        lastError << std::endl;
#endif
      return false;
    }
  }

  assert(compressedBufferSize > 0);

  std::string result;
  result.resize(compressedBufferSize);

  SIZE_T compressedDataSize = 0;

  //  Compress
  success = ::Compress(
    compressor,                  //  Compressor Handle
    const_cast<char*>(input),    //  Input buffer
    length,                      //  Uncompressed data size
    &result[0],                  //  Compressed Buffer
    compressedBufferSize,        //  Compressed Buffer size
    &compressedDataSize);        //  Compressed Data size

  if (!success) {
#ifdef _DEBUG
    std::cerr << "XPRESS: Failed to compress LastError " <<
      GetLastError() << std::endl;
#endif
    return false;
  }

  result.resize(compressedDataSize);
  output->swap(result);

  return true;
}

char* Decompress(const char* input_data, size_t input_length,
  int* decompress_size) {

  assert(input_data != nullptr);
  assert(decompress_size != nullptr);

  if (input_length == 0) {
    return nullptr;
  }

  COMPRESS_ALLOCATION_ROUTINES* allocRoutinesPtr = nullptr;

  DECOMPRESSOR_HANDLE decompressor = NULL;

  BOOL success = CreateDecompressor(
    COMPRESS_ALGORITHM_XPRESS, //  Compression Algorithm
    allocRoutinesPtr,          //  Optional allocation routine
    &decompressor);            //  Handle


  if (!success) {
#ifdef _DEBUG
    std::cerr << "XPRESS: Failed to create Decompressor LastError "
      << GetLastError() << std::endl;
#endif
    return nullptr;
  }

  std::unique_ptr<void, decltype(CloseDecompressorFun)>
    compressorGuard(decompressor, CloseDecompressorFun);

  SIZE_T decompressedBufferSize = 0;

  success = ::Decompress(
    decompressor,          //  Compressor Handle
    const_cast<char*>(input_data),  //  Compressed data
    input_length,               //  Compressed data size
    NULL,                        //  Buffer set to NULL
    0,                           //  Buffer size set to 0
    &decompressedBufferSize);    //  Decompressed Data size

  if (!success) {

    auto lastError = GetLastError();

    if (lastError != ERROR_INSUFFICIENT_BUFFER) {
#ifdef _DEBUG
      std::cerr
        << "XPRESS: Failed to estimate decompressed buffer size LastError "
        << lastError << std::endl;
#endif
      return nullptr;
    }
  }

  assert(decompressedBufferSize > 0);

  // On Windows we are limited to a 32-bit int for the
  // output data size argument
  // so we hopefully never get here
  if (decompressedBufferSize > std::numeric_limits<int>::max()) {
    assert(false);
    return nullptr;
  }

  // The callers are deallocating using delete[]
  // thus we must allocate with new[]
  std::unique_ptr<char[]> outputBuffer(new char[decompressedBufferSize]);

  SIZE_T decompressedDataSize = 0;

  success = ::Decompress(
    decompressor,
    const_cast<char*>(input_data),
    input_length,
    outputBuffer.get(),
    decompressedBufferSize,
    &decompressedDataSize);

  if (!success) {
#ifdef _DEBUG
    std::cerr <<
      "XPRESS: Failed to decompress LastError " <<
      GetLastError() << std::endl;
#endif
    return nullptr;
  }

  *decompress_size = static_cast<int>(decompressedDataSize);

  // Return the raw buffer to the caller supporting the tradition
  return outputBuffer.release();
}
}
}
}

#endif