1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
2 // vim: ts=8 sw=2 smarttab
4 * Ceph - scalable distributed file system
6 * Copyright (C) 2017 Haomai Wang <haomaiwang@gmail.com>
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.
15 #ifndef CEPH_LZ4COMPRESSOR_H
16 #define CEPH_LZ4COMPRESSOR_H
20 #include "compressor/Compressor.h"
21 #include "include/buffer.h"
22 #include "include/encoding.h"
23 #include "common/Tub.h"
26 class LZ4Compressor : public Compressor {
28 LZ4Compressor() : Compressor(COMP_ALG_LZ4, "lz4") {}
30 int compress(const bufferlist &src, bufferlist &dst) override {
31 bufferptr outptr = buffer::create_page_aligned(
32 LZ4_compressBound(src.length()));
33 LZ4_stream_t lz4_stream;
34 LZ4_resetStream(&lz4_stream);
37 size_t left = src.length();
40 unsigned num = src.get_num_buffers();
42 uint32_t compressed_len;
43 ::encode((uint32_t)num, dst);
45 origin_len = p.get_ptr_and_advance(left, &data);
46 compressed_len = LZ4_compress_fast_continue(
47 &lz4_stream, data, outptr.c_str()+pos, origin_len,
48 outptr.length()-pos, 1);
49 if (compressed_len <= 0)
51 pos += compressed_len;
53 ::encode(origin_len, dst);
54 ::encode(compressed_len, dst);
58 dst.append(outptr, 0, pos);
62 int decompress(const bufferlist &src, bufferlist &dst) override {
63 bufferlist::iterator i = const_cast<bufferlist&>(src).begin();
64 return decompress(i, src.length(), dst);
67 int decompress(bufferlist::iterator &p,
68 size_t compressed_len,
69 bufferlist &dst) override {
71 std::vector<std::pair<uint32_t, uint32_t> > compressed_pairs;
73 compressed_pairs.resize(count);
74 uint32_t total_origin = 0;
75 for (unsigned i = 0; i < count; ++i) {
76 ::decode(compressed_pairs[i].first, p);
77 ::decode(compressed_pairs[i].second, p);
78 total_origin += compressed_pairs[i].first;
80 compressed_len -= (sizeof(uint32_t) + sizeof(uint32_t) * count * 2);
82 bufferptr dstptr(total_origin);
83 LZ4_streamDecode_t lz4_stream_decode;
84 LZ4_setStreamDecode(&lz4_stream_decode, nullptr, 0);
86 bufferptr cur_ptr = p.get_current_ptr();
87 bufferptr *ptr = &cur_ptr;
88 Tub<bufferptr> data_holder;
89 if (compressed_len != cur_ptr.length()) {
90 data_holder.construct(compressed_len);
91 p.copy_deep(compressed_len, *data_holder);
92 ptr = data_holder.get();
95 char *c_in = ptr->c_str();
96 char *c_out = dstptr.c_str();
97 for (unsigned i = 0; i < count; ++i) {
98 int r = LZ4_decompress_safe_continue(
99 &lz4_stream_decode, c_in, c_out, compressed_pairs[i].second, compressed_pairs[i].first);
100 if (r == (int)compressed_pairs[i].first) {
101 c_in += compressed_pairs[i].second;
102 c_out += compressed_pairs[i].first;
105 } else if (r != (int)compressed_pairs[i].first) {
109 dst.push_back(std::move(dstptr));