initial code repo

[stor4nfv.git] / src / ceph / src / compressor / snappy / SnappyCompressor.h

diff --git a/src/ceph/src/compressor/snappy/SnappyCompressor.h b/src/ceph/src/compressor/snappy/SnappyCompressor.h
new file mode 100644 (file)
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+++ b/src/ceph/src/compressor/snappy/SnappyCompressor.h
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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) 2015 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_SNAPPYCOMPRESSOR_H
+#define CEPH_SNAPPYCOMPRESSOR_H
+
+#include <snappy.h>
+#include <snappy-sinksource.h>
+#include "compressor/Compressor.h"
+#include "include/buffer.h"
+
+class CEPH_BUFFER_API BufferlistSource : public snappy::Source {
+  bufferlist::iterator pb;
+  size_t remaining;
+
+ public:
+  explicit BufferlistSource(bufferlist::iterator _pb, size_t _input_len)
+    : pb(_pb),
+      remaining(_input_len) {
+    remaining = std::min(remaining, (size_t)pb.get_remaining());
+  }
+  size_t Available() const override {
+    return remaining;
+  }
+  const char *Peek(size_t *len) override {
+    const char *data = NULL;
+    *len = 0;
+    size_t avail = Available();
+    if (avail) {
+      auto ptmp = pb;
+      *len = ptmp.get_ptr_and_advance(avail, &data);
+    }
+    return data;
+  }
+  void Skip(size_t n) override {
+    assert(n <= remaining);
+    pb.advance(n);
+    remaining -= n;
+  }
+
+  bufferlist::iterator get_pos() const {
+    return pb;
+  }
+};
+
+class SnappyCompressor : public Compressor {
+ public:
+  SnappyCompressor() : Compressor(COMP_ALG_SNAPPY, "snappy") {}
+
+  int compress(const bufferlist &src, bufferlist &dst) override {
+    BufferlistSource source(const_cast<bufferlist&>(src).begin(), src.length());
+    bufferptr ptr = buffer::create_page_aligned(
+      snappy::MaxCompressedLength(src.length()));
+    snappy::UncheckedByteArraySink sink(ptr.c_str());
+    snappy::Compress(&source, &sink);
+    dst.append(ptr, 0, sink.CurrentDestination() - ptr.c_str());
+    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 {
+    snappy::uint32 res_len = 0;
+    BufferlistSource source_1(p, compressed_len);
+    if (!snappy::GetUncompressedLength(&source_1, &res_len)) {
+      return -1;
+    }
+    BufferlistSource source_2(p, compressed_len);
+    bufferptr ptr(res_len);
+    if (snappy::RawUncompress(&source_2, ptr.c_str())) {
+      p = source_2.get_pos();
+      dst.append(ptr);
+      return 0;
+    }
+    return -2;
+  }
+};
+
+#endif