ceph/src/compressor/zstd/ZstdCompressor.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_ZSTDCOMPRESSOR_H
  16 #define CEPH_ZSTDCOMPRESSOR_H
  17
  18 #define ZSTD_STATIC_LINKING_ONLY
  19 #include "zstd/lib/zstd.h"
  20
  21 #include "include/buffer.h"
  22 #include "include/encoding.h"
  23 #include "compressor/Compressor.h"
  24
  25 class ZstdCompressor : public Compressor {
  26  public:
  27   ZstdCompressor(CephContext *cct) : Compressor(COMP_ALG_ZSTD, "zstd"), cct(cct) {}
  28
  29   int compress(const bufferlist &src, bufferlist &dst) override {
  30     ZSTD_CStream *s = ZSTD_createCStream();
  31     ZSTD_initCStream_srcSize(s, cct->_conf->compressor_zstd_level, src.length());
  32     auto p = src.begin();
  33     size_t left = src.length();
  34
  35     size_t const out_max = ZSTD_compressBound(left);
  36     bufferptr outptr = buffer::create_small_page_aligned(out_max);
  37     ZSTD_outBuffer_s outbuf;
  38     outbuf.dst = outptr.c_str();
  39     outbuf.size = outptr.length();
  40     outbuf.pos = 0;
  41
  42     while (left) {
  43       ceph_assert(!p.end());
  44       struct ZSTD_inBuffer_s inbuf;
  45       inbuf.pos = 0;
  46       inbuf.size = p.get_ptr_and_advance(left, (const char**)&inbuf.src);
  47       left -= inbuf.size;
  48       ZSTD_EndDirective const zed = (left==0) ? ZSTD_e_end : ZSTD_e_continue;
  49       size_t r = ZSTD_compressStream2(s, &outbuf, &inbuf, zed);
  50       if (ZSTD_isError(r)) {
  51         return -EINVAL;
  52       }
  53     }
  54     ceph_assert(p.end());
  55
  56     ZSTD_freeCStream(s);
  57
  58     // prefix with decompressed length
  59     encode((uint32_t)src.length(), dst);
  60     dst.append(outptr, 0, outbuf.pos);
  61     return 0;
  62   }
  63
  64   int decompress(const bufferlist &src, bufferlist &dst) override {
  65     auto i = std::cbegin(src);
  66     return decompress(i, src.length(), dst);
  67   }
  68
  69   int decompress(bufferlist::const_iterator &p,
  70                  size_t compressed_len,
  71                  bufferlist &dst) override {
  72     if (compressed_len < 4) {
  73       return -1;
  74     }
  75     compressed_len -= 4;
  76     uint32_t dst_len;
  77     decode(dst_len, p);
  78
  79     bufferptr dstptr(dst_len);
  80     ZSTD_outBuffer_s outbuf;
  81     outbuf.dst = dstptr.c_str();
  82     outbuf.size = dstptr.length();
  83     outbuf.pos = 0;
  84     ZSTD_DStream *s = ZSTD_createDStream();
  85     ZSTD_initDStream(s);
  86     while (compressed_len > 0) {
  87       if (p.end()) {
  88         return -1;
  89       }
  90       ZSTD_inBuffer_s inbuf;
  91       inbuf.pos = 0;
  92       inbuf.size = p.get_ptr_and_advance(compressed_len,
  93                                          (const char**)&inbuf.src);
  94       ZSTD_decompressStream(s, &outbuf, &inbuf);
  95       compressed_len -= inbuf.size;
  96     }
  97     ZSTD_freeDStream(s);
  98
  99     dst.append(dstptr, 0, outbuf.pos);
 100     return 0;
 101   }
 102  private:
 103   CephContext *const cct;
 104 };
 105
 106 #endif