zlib_source.h

// Copyright 2013, Beeri 15.  All rights reserved.
// Author: Roman Gershman (romange@gmail.com)
//
#pragma once


#include <zlib.h>

#include "base/macros.h"
#include "util/sinksource.h"

namespace util {

class ZlibSource : public Source {
 public:
  // Format key for constructor
  enum Format {
    // zlib will autodetect gzip header or deflate stream
    AUTO = 0,

    // GZIP streams have some extra header data for file attributes.
    GZIP = 1,

    // Simpler zlib stream format.
    ZLIB = 2,
  };


  // buffer_size and format may be -1 for default of 64kB and GZIP format.
  explicit ZlibSource(Source* sub_source, Format format = AUTO);
  ~ZlibSource();

  static bool IsZlibSource(Source* source);

 private:

  StatusObject<size_t> ReadInternal(const strings::MutableByteRange& range) override;

  Source* sub_stream_;

  Format format_;
  z_stream zcontext_;
  std::unique_ptr<uint8_t[]> buf_;

  int Inflate();

  bool RefillInternal();

  DISALLOW_EVIL_CONSTRUCTORS(ZlibSource);
};

class ZlibSink : public Sink {
 public:
  // Takes ownership over sub-sink.
  explicit ZlibSink(Sink* sub, unsigned level = 0, size_t buf_size = 1 << 16);
  ~ZlibSink() final;

  Status Append(const strings::ByteRange& slice) final;
  Status Flush() final;

 private:
  std::unique_ptr<Sink> sub_;
  std::unique_ptr<uint8_t[]> buf_;
  size_t buf_size_;
  z_stream zcontext_;
};

}  // namespace util