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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2017 Haomai Wang <haomaiwang@gmail.com>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_LZ4COMPRESSOR_H
#define CEPH_LZ4COMPRESSOR_H
#include <lz4.h>
#include "compressor/Compressor.h"
#include "include/buffer.h"
#include "include/encoding.h"
#include "common/config.h"
#include "common/Tub.h"
class LZ4Compressor : public Compressor {
public:
LZ4Compressor(CephContext* cct) : Compressor(COMP_ALG_LZ4, "lz4") {
#ifdef HAVE_QATZIP
if (cct->_conf->qat_compressor_enabled && qat_accel.init("lz4"))
qat_enabled = true;
else
qat_enabled = false;
#endif
}
int compress(const bufferlist &src, bufferlist &dst) override {
// older versions of liblz4 introduce bit errors when compressing
// fragmented buffers. this was fixed in lz4 commit
// af127334670a5e7b710bbd6adb71aa7c3ef0cd72, which first
// appeared in v1.8.2.
//
// workaround: rebuild if not contiguous.
if (!src.is_contiguous()) {
bufferlist new_src = src;
new_src.rebuild();
return compress(new_src, dst);
}
#ifdef HAVE_QATZIP
if (qat_enabled)
return qat_accel.compress(src, dst);
#endif
bufferptr outptr = buffer::create_small_page_aligned(
LZ4_compressBound(src.length()));
LZ4_stream_t lz4_stream;
LZ4_resetStream(&lz4_stream);
auto p = src.begin();
size_t left = src.length();
int pos = 0;
const char *data;
unsigned num = src.get_num_buffers();
encode((uint32_t)num, dst);
while (left) {
uint32_t origin_len = p.get_ptr_and_advance(left, &data);
int compressed_len = LZ4_compress_fast_continue(
&lz4_stream, data, outptr.c_str()+pos, origin_len,
outptr.length()-pos, 1);
if (compressed_len <= 0)
return -1;
pos += compressed_len;
left -= origin_len;
encode(origin_len, dst);
encode((uint32_t)compressed_len, dst);
}
ceph_assert(p.end());
dst.append(outptr, 0, pos);
return 0;
}
int decompress(const bufferlist &src, bufferlist &dst) override {
#ifdef HAVE_QATZIP
if (qat_enabled)
return qat_accel.decompress(src, dst);
#endif
auto i = std::cbegin(src);
return decompress(i, src.length(), dst);
}
int decompress(bufferlist::const_iterator &p,
size_t compressed_len,
bufferlist &dst) override {
#ifdef HAVE_QATZIP
if (qat_enabled)
return qat_accel.decompress(p, compressed_len, dst);
#endif
uint32_t count;
std::vector<std::pair<uint32_t, uint32_t> > compressed_pairs;
decode(count, p);
compressed_pairs.resize(count);
uint32_t total_origin = 0;
for (unsigned i = 0; i < count; ++i) {
decode(compressed_pairs[i].first, p);
decode(compressed_pairs[i].second, p);
total_origin += compressed_pairs[i].first;
}
compressed_len -= (sizeof(uint32_t) + sizeof(uint32_t) * count * 2);
bufferptr dstptr(total_origin);
LZ4_streamDecode_t lz4_stream_decode;
LZ4_setStreamDecode(&lz4_stream_decode, nullptr, 0);
bufferptr cur_ptr = p.get_current_ptr();
bufferptr *ptr = &cur_ptr;
Tub<bufferptr> data_holder;
if (compressed_len != cur_ptr.length()) {
data_holder.construct(compressed_len);
p.copy_deep(compressed_len, *data_holder);
ptr = data_holder.get();
}
char *c_in = ptr->c_str();
char *c_out = dstptr.c_str();
for (unsigned i = 0; i < count; ++i) {
int r = LZ4_decompress_safe_continue(
&lz4_stream_decode, c_in, c_out, compressed_pairs[i].second, compressed_pairs[i].first);
if (r == (int)compressed_pairs[i].first) {
c_in += compressed_pairs[i].second;
c_out += compressed_pairs[i].first;
} else if (r < 0) {
return -1;
} else {
return -2;
}
}
dst.push_back(std::move(dstptr));
return 0;
}
};
#endif
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