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 #define COMPRESSION_LEVEL 5
  26
  27 class ZstdCompressor : public Compressor {
  28  public:
  29   ZstdCompressor() : Compressor(COMP_ALG_ZSTD, "zstd") {}
  30
  31   int compress(const bufferlist &src, bufferlist &dst) override {
  32     ZSTD_CStream *s = ZSTD_createCStream();
  33     ZSTD_initCStream_srcSize(s, COMPRESSION_LEVEL, src.length());
  34     auto p = src.begin();
  35     size_t left = src.length();
  36
  37     size_t const out_max = ZSTD_compressBound(left);
  38     bufferptr outptr = buffer::create_small_page_aligned(out_max);
  39     ZSTD_outBuffer_s outbuf;
  40     outbuf.dst = outptr.c_str();
  41     outbuf.size = outptr.length();
  42     outbuf.pos = 0;
  43
  44     while (left) {
  45       ceph_assert(!p.end());
  46       struct ZSTD_inBuffer_s inbuf;
  47       inbuf.pos = 0;
  48       inbuf.size = p.get_ptr_and_advance(left, (const char**)&inbuf.src);
  49       left -= inbuf.size;
  50       ZSTD_EndDirective const zed = (left==0) ? ZSTD_e_end : ZSTD_e_continue;
  51       size_t r = ZSTD_compressStream2(s, &outbuf, &inbuf, zed);
  52       if (ZSTD_isError(r)) {
  53         return -EINVAL;
  54       }
  55     }
  56     ceph_assert(p.end());
  57
  58     ZSTD_freeCStream(s);
  59
  60     // prefix with decompressed length
  61     encode((uint32_t)src.length(), dst);
  62     dst.append(outptr, 0, outbuf.pos);
  63     return 0;
  64   }
  65
  66   int decompress(const bufferlist &src, bufferlist &dst) override {
  67     auto i = std::cbegin(src);
  68     return decompress(i, src.length(), dst);
  69   }
  70
  71   int decompress(bufferlist::const_iterator &p,
  72                  size_t compressed_len,
  73                  bufferlist &dst) override {
  74     if (compressed_len < 4) {
  75       return -1;
  76     }
  77     compressed_len -= 4;
  78     uint32_t dst_len;
  79     decode(dst_len, p);
  80
  81     bufferptr dstptr(dst_len);
  82     ZSTD_outBuffer_s outbuf;
  83     outbuf.dst = dstptr.c_str();
  84     outbuf.size = dstptr.length();
  85     outbuf.pos = 0;
  86     ZSTD_DStream *s = ZSTD_createDStream();
  87     ZSTD_initDStream(s);
  88     while (compressed_len > 0) {
  89       if (p.end()) {
  90         return -1;
  91       }
  92       ZSTD_inBuffer_s inbuf;
  93       inbuf.pos = 0;
  94       inbuf.size = p.get_ptr_and_advance(compressed_len,
  95                                          (const char**)&inbuf.src);
  96       ZSTD_decompressStream(s, &outbuf, &inbuf);
  97       compressed_len -= inbuf.size;
  98     }
  99     ZSTD_freeDStream(s);
 100
 101     dst.append(dstptr, 0, outbuf.pos);
 102     return 0;
 103   }
 104 };
 105
 106 #endif