ceph/src/compressor/Compressor.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2015 Haomai Wang <haomaiwang@gmail.com>
   7  *
   8  * This is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License version 2.1, as published by the Free Software
  11  * Foundation.  See file COPYING.
  12  *
  13  */
  14
  15 #ifndef CEPH_COMPRESSOR_H
  16 #define CEPH_COMPRESSOR_H
  17
  18 #include <string>
  19 #include <boost/optional.hpp>
  20 #include "include/memory.h"
  21 #include "include/buffer.h"
  22
  23 class Compressor;
  24 typedef shared_ptr<Compressor> CompressorRef;
  25
  26 class Compressor {
  27 public:
  28   enum CompressionAlgorithm {
  29     COMP_ALG_NONE = 0,
  30     COMP_ALG_SNAPPY = 1,
  31     COMP_ALG_ZLIB = 2,
  32     COMP_ALG_ZSTD = 3,
  33     COMP_ALG_LAST       //the last value for range checks
  34   };
  35   // compression options
  36   enum CompressionMode {
  37     COMP_NONE,                  ///< compress never
  38     COMP_PASSIVE,               ///< compress if hinted COMPRESSIBLE
  39     COMP_AGGRESSIVE,            ///< compress unless hinted INCOMPRESSIBLE
  40     COMP_FORCE                  ///< compress always
  41   };
  42
  43   static const char * get_comp_alg_name(int a);
  44   static boost::optional<CompressionAlgorithm> get_comp_alg_type(const std::string &s);
  45
  46   static const char *get_comp_mode_name(int m);
  47   static boost::optional<CompressionMode> get_comp_mode_type(const std::string &s);
  48
  49   Compressor(CompressionAlgorithm a, const char* t) : alg(a), type(t) {
  50   }
  51   virtual ~Compressor() {}
  52   const std::string& get_type_name() const {
  53     return type;
  54   }
  55   CompressionAlgorithm get_type() const {
  56     return alg;
  57   }
  58   virtual int compress(const bufferlist &in, bufferlist &out) = 0;
  59   virtual int decompress(const bufferlist &in, bufferlist &out) = 0;
  60   // this is a bit weird but we need non-const iterator to be in
  61   // alignment with decode methods
  62   virtual int decompress(bufferlist::iterator &p, size_t compressed_len, bufferlist &out) = 0;
  63
  64   static CompressorRef create(CephContext *cct, const std::string &type);
  65   static CompressorRef create(CephContext *cct, int alg);
  66
  67 protected:
  68   CompressionAlgorithm alg;
  69   std::string type;
  70
  71 };
  72
  73 #endif