--- /dev/null
+// -*- 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/Tub.h"
+
+
+class LZ4Compressor : public Compressor {
+ public:
+ LZ4Compressor() : Compressor(COMP_ALG_LZ4, "lz4") {}
+
+ int compress(const bufferlist &src, bufferlist &dst) override {
+ bufferptr outptr = buffer::create_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();
+ uint32_t origin_len;
+ uint32_t compressed_len;
+ ::encode((uint32_t)num, dst);
+ while (left) {
+ origin_len = p.get_ptr_and_advance(left, &data);
+ 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(compressed_len, dst);
+ }
+ assert(p.end());
+
+ dst.append(outptr, 0, pos);
+ return 0;
+ }
+
+ int decompress(const bufferlist &src, bufferlist &dst) override {
+ bufferlist::iterator i = const_cast<bufferlist&>(src).begin();
+ return decompress(i, src.length(), dst);
+ }
+
+ int decompress(bufferlist::iterator &p,
+ size_t compressed_len,
+ bufferlist &dst) override {
+ 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 if (r != (int)compressed_pairs[i].first) {
+ return -2;
+ }
+ }
+ dst.push_back(std::move(dstptr));
+ return 0;
+ }
+};
+
+#endif