1 files changed, 144 insertions, 0 deletions
diff --git a/src/compressor/lz4/LZ4Compressor.h b/src/compressor/lz4/LZ4Compressor.h
new file mode 100644
index 00000000..6e604d5c
--- /dev/null
+++ b/src/compressor/lz4/LZ4Compressor.h
@@ -0,0 +1,144 @@
+// -*- 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