YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

#include "yb/util/zlib.h"

#include <zlib.h>

#include <memory>

#include <string>

#include "yb/gutil/casts.h"

#include "yb/gutil/macros.h"

#include "yb/util/slice.h"

#include "yb/util/status.h"

#include "yb/util/status_format.h"

using std::ostream;

using std::string;

using std::unique_ptr;

#define ZRETURN_NOT_OK(call) \

  RETURN_NOT_OK(ZlibResultToStatus(call))

namespace yb {

namespace zlib {

namespace  {

Status ZlibResultToStatus(int rc) {

  switch (rc) {

    case Z_OK:

      return Status::OK();

    case Z_STREAM_END:

      return STATUS(EndOfFile, "zlib EOF");

    case Z_NEED_DICT:

      return STATUS(Corruption, "zlib error: NEED_DICT");

    case Z_ERRNO:

      return STATUS(IOError, "zlib error: Z_ERRNO");

    case Z_STREAM_ERROR:

      return STATUS(Corruption, "zlib error: STREAM_ERROR");

    case Z_DATA_ERROR:

      return STATUS(Corruption, "zlib error: DATA_ERROR");

    case Z_MEM_ERROR:

      return STATUS(RuntimeError, "zlib error: MEM_ERROR");

    case Z_BUF_ERROR:

      return STATUS(RuntimeError, "zlib error: BUF_ERROR");

    case Z_VERSION_ERROR:

      return STATUS(RuntimeError, "zlib error: VERSION_ERROR");

    default:

      return STATUS_FORMAT(RuntimeError, "zlib error: unknown error $0", rc);

  }

}

} // anonymous namespace

Status Compress(Slice input, ostream* out) {

  return CompressLevel(input, Z_DEFAULT_COMPRESSION, out);

}

// See https://zlib.net/zlib_how.html for context on using zlib.

Status CompressLevel(Slice input, int level, ostream* out) {

  z_stream zs;

  memset(&zs, 0, sizeof(zs));

  ZRETURN_NOT_OK(deflateInit2(&zs, level, Z_DEFLATED,

                              MAX_WBITS + 16 /* enable gzip */,

                              8 /* memory level, max is 9 */,

                              Z_DEFAULT_STRATEGY));

  zs.avail_in = narrow_cast<uInt>(input.size());

  zs.next_in = const_cast<uint8_t*>(input.data());

  const int kChunkSize = 64 * 1024;

  unique_ptr<unsigned char[]> chunk(new unsigned char[kChunkSize]);

  int flush;

  do {

    zs.avail_out = kChunkSize;

    zs.next_out = chunk.get();

    flush = (zs.avail_in == 0) ? Z_FINISH : Z_NO_FLUSH;

    Status s = ZlibResultToStatus(deflate(&zs, flush));

    if (!s.ok() && !s.IsEndOfFile()) {

      deflateEnd(&zs);

      return s;

    }

    auto out_size = zs.next_out - chunk.get();

    if (out_size > 0) {

      out->write(reinterpret_cast<char *>(chunk.get()), out_size);

    }

  } while (flush != Z_FINISH);

  ZRETURN_NOT_OK(deflateEnd(&zs));

  return Status::OK();

}

// See https://zlib.net/zlib_how.html for context on using zlib.

Status Uncompress(const Slice& compressed, std::ostream* out) {

  // Initialize the z_stream at the start of the data with the

  // data size as the available input.

  z_stream zs;

  memset(&zs, 0, sizeof(zs));

  zs.next_in = const_cast<uint8_t*>(compressed.data());

  zs.avail_in = narrow_cast<uInt>(compressed.size());

  // Initialize inflation with the windowBits set to be GZIP compatible.

  // The documentation (https://www.zlib.net/manual.html#Advanced) describes that

  // Adding 16 configures inflate to decode the gzip format.

  ZRETURN_NOT_OK(inflateInit2(&zs, MAX_WBITS + 16 /* enable gzip */));

  // Continue calling inflate, decompressing data into the buffer in `zs.next_out` and writing

  // the buffer content to `out`, until an error is received or there is no more data

  // to decompress.

  Status s;

  do {

    unsigned char buf[4096];

    zs.next_out = buf;

    zs.avail_out = arraysize(buf);

    s = ZlibResultToStatus(inflate(&zs, Z_NO_FLUSH));

    if (!s.ok() && !s.IsEndOfFile()) {

      inflateEnd(&zs);

      return s;

    }

    out->write(reinterpret_cast<char *>(buf), zs.next_out - buf);

  } while (zs.avail_out == 0);

  // If we haven't returned early with a bad status, finalize inflation.

  ZRETURN_NOT_OK(inflateEnd(&zs));

  return Status::OK();

}

} // namespace zlib

} // namespace yb