initial code repo

[stor4nfv.git] / src / ceph / src / compressor / lz4 / LZ4Compressor.h

diff --git a/src/ceph/src/compressor/lz4/LZ4Compressor.h b/src/ceph/src/compressor/lz4/LZ4Compressor.h
new file mode 100644 (file)
index 0000000..55e816b
--- /dev/null
+++ b/src/ceph/src/compressor/lz4/LZ4Compressor.h
@@ -0,0 +1,114 @@
+// -*- 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