X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fsrc%2Fcommon%2Fbit_vector.hpp;fp=src%2Fceph%2Fsrc%2Fcommon%2Fbit_vector.hpp;h=b010970b3213d4fae377a2bb25bb8e778d7b4951;hb=812ff6ca9fcd3e629e49d4328905f33eee8ca3f5;hp=0000000000000000000000000000000000000000;hpb=15280273faafb77777eab341909a3f495cf248d9;p=stor4nfv.git

diff --git a/src/ceph/src/common/bit_vector.hpp b/src/ceph/src/common/bit_vector.hpp
new file mode 100644
index 0000000..b010970
--- /dev/null
+++ b/src/ceph/src/common/bit_vector.hpp
@@ -0,0 +1,520 @@
+// -*- 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) 2014 Red Hat <contact@redhat.com>
+ *
+ * LGPL2.1 (see COPYING-LGPL2.1) or later
+ */
+
+#ifndef BIT_VECTOR_HPP
+#define BIT_VECTOR_HPP
+
+#include "common/Formatter.h"
+#include "include/assert.h"
+#include "include/encoding.h"
+#include <utility>
+
+namespace ceph {
+
+template <uint8_t _bit_count>
+class BitVector
+{
+private:
+  static const uint8_t BITS_PER_BYTE = 8;
+  static const uint32_t ELEMENTS_PER_BLOCK = BITS_PER_BYTE / _bit_count;
+  static const uint8_t MASK = static_cast<uint8_t>((1 << _bit_count) - 1);
+
+  // must be power of 2
+  BOOST_STATIC_ASSERT((_bit_count != 0) && !(_bit_count & (_bit_count - 1)));
+  BOOST_STATIC_ASSERT(_bit_count <= BITS_PER_BYTE);
+
+  template <typename DataIterator>
+  class ReferenceImpl {
+  protected:
+    DataIterator m_data_iterator;
+    uint64_t m_shift;
+
+    ReferenceImpl(const DataIterator& data_iterator, uint64_t shift)
+      : m_data_iterator(data_iterator), m_shift(shift) {
+    }
+    ReferenceImpl(DataIterator&& data_iterator, uint64_t shift)
+      : m_data_iterator(std::move(data_iterator)), m_shift(shift) {
+    }
+
+  public:
+    inline operator uint8_t() const {
+      return (*m_data_iterator >> m_shift) & MASK;
+    }
+  };
+
+public:
+
+  class ConstReference : public ReferenceImpl<bufferlist::const_iterator> {
+  private:
+    friend class BitVector;
+
+    ConstReference(const bufferlist::const_iterator& data_iterator,
+                   uint64_t shift)
+      : ReferenceImpl<bufferlist::const_iterator>(data_iterator, shift) {
+    }
+    ConstReference(bufferlist::const_iterator&& data_iterator, uint64_t shift)
+      : ReferenceImpl<bufferlist::const_iterator>(std::move(data_iterator),
+                                                  shift) {
+    }
+  };
+
+  class Reference : public ReferenceImpl<bufferlist::iterator> {
+  public:
+    Reference& operator=(uint8_t v);
+
+  private:
+    friend class BitVector;
+
+    Reference(const bufferlist::iterator& data_iterator, uint64_t shift)
+      : ReferenceImpl<bufferlist::iterator>(data_iterator, shift) {
+    }
+    Reference(bufferlist::iterator&& data_iterator, uint64_t shift)
+      : ReferenceImpl<bufferlist::iterator>(std::move(data_iterator), shift) {
+    }
+  };
+
+public:
+  template <typename BitVectorT, typename DataIterator>
+  class IteratorImpl {
+  private:
+    friend class BitVector;
+
+    uint64_t m_offset = 0;
+    BitVectorT *m_bit_vector;
+
+    // cached derived values
+    uint64_t m_index = 0;
+    uint64_t m_shift = 0;
+    DataIterator m_data_iterator;
+
+    IteratorImpl(BitVectorT *bit_vector, uint64_t offset)
+      : m_bit_vector(bit_vector),
+        m_data_iterator(bit_vector->m_data.begin()) {
+      *this += offset;
+    }
+
+  public:
+    inline IteratorImpl& operator++() {
+      ++m_offset;
+
+      uint64_t index;
+      compute_index(m_offset, &index, &m_shift);
+
+      assert(index == m_index || index == m_index + 1);
+      if (index > m_index) {
+        m_index = index;
+        ++m_data_iterator;
+      }
+      return *this;
+    }
+    inline IteratorImpl& operator+=(uint64_t offset) {
+      m_offset += offset;
+      compute_index(m_offset, &m_index, &m_shift);
+      if (m_offset < m_bit_vector->size()) {
+        m_data_iterator.seek(m_index);
+      } else {
+        m_data_iterator = m_bit_vector->m_data.end();
+      }
+      return *this;
+    }
+
+    inline IteratorImpl operator++(int) {
+      IteratorImpl iterator_impl(*this);
+      ++iterator_impl;
+      return iterator_impl;
+    }
+    inline IteratorImpl operator+(uint64_t offset) {
+      IteratorImpl iterator_impl(*this);
+      iterator_impl += offset;
+      return iterator_impl;
+    }
+
+    inline bool operator==(const IteratorImpl& rhs) const {
+      return (m_offset == rhs.m_offset && m_bit_vector == rhs.m_bit_vector);
+    }
+    inline bool operator!=(const IteratorImpl& rhs) const {
+      return (m_offset != rhs.m_offset || m_bit_vector != rhs.m_bit_vector);
+    }
+
+    inline ConstReference operator*() const {
+      return ConstReference(m_data_iterator, m_shift);
+    }
+    inline Reference operator*() {
+      return Reference(m_data_iterator, m_shift);
+    }
+  };
+
+  typedef IteratorImpl<const BitVector,
+                       bufferlist::const_iterator> ConstIterator;
+  typedef IteratorImpl<BitVector, bufferlist::iterator> Iterator;
+
+  static const uint32_t BLOCK_SIZE;
+  static const uint8_t BIT_COUNT = _bit_count;
+
+  BitVector();
+
+  inline ConstIterator begin() const {
+    return ConstIterator(this, 0);
+  }
+  inline ConstIterator end() const {
+    return ConstIterator(this, m_size);
+  }
+  inline Iterator begin() {
+    return Iterator(this, 0);
+  }
+  inline Iterator end() {
+    return Iterator(this, m_size);
+  }
+
+  void set_crc_enabled(bool enabled) {
+    m_crc_enabled = enabled;
+  }
+  void clear();
+
+  void resize(uint64_t elements);
+  uint64_t size() const;
+
+  const bufferlist& get_data() const;
+
+  Reference operator[](uint64_t offset);
+  ConstReference operator[](uint64_t offset) const;
+
+  void encode_header(bufferlist& bl) const;
+  void decode_header(bufferlist::iterator& it);
+  uint64_t get_header_length() const;
+
+  void encode_data(bufferlist& bl, uint64_t byte_offset,
+		   uint64_t byte_length) const;
+  void decode_data(bufferlist::iterator& it, uint64_t byte_offset);
+  void get_data_extents(uint64_t offset, uint64_t length,
+		        uint64_t *byte_offset, uint64_t *byte_length) const;
+
+  void encode_footer(bufferlist& bl) const;
+  void decode_footer(bufferlist::iterator& it);
+  uint64_t get_footer_offset() const;
+
+  void encode(bufferlist& bl) const;
+  void decode(bufferlist::iterator& it);
+  void dump(Formatter *f) const;
+
+  bool operator==(const BitVector &b) const;
+
+  static void generate_test_instances(std::list<BitVector *> &o);
+private:
+
+  bufferlist m_data;
+  uint64_t m_size;
+  bool m_crc_enabled;
+
+  mutable __u32 m_header_crc;
+  mutable std::vector<__u32> m_data_crcs;
+
+  static void compute_index(uint64_t offset, uint64_t *index, uint64_t *shift);
+
+};
+
+template <uint8_t _b>
+const uint32_t BitVector<_b>::BLOCK_SIZE = 4096;
+
+template <uint8_t _b>
+BitVector<_b>::BitVector() : m_size(0), m_crc_enabled(true), m_header_crc(0)
+{
+}
+
+template <uint8_t _b>
+void BitVector<_b>::clear() {
+  m_data.clear();
+  m_data_crcs.clear();
+  m_size = 0;
+  m_header_crc = 0;
+}
+
+template <uint8_t _b>
+void BitVector<_b>::resize(uint64_t size) {
+  uint64_t buffer_size = (size + ELEMENTS_PER_BLOCK - 1) / ELEMENTS_PER_BLOCK;
+  if (buffer_size > m_data.length()) {
+    m_data.append_zero(buffer_size - m_data.length());
+  } else if (buffer_size < m_data.length()) {
+    bufferlist bl;
+    bl.substr_of(m_data, 0, buffer_size);
+    bl.swap(m_data);
+  }
+  m_size = size;
+
+  uint64_t block_count = (buffer_size + BLOCK_SIZE - 1) / BLOCK_SIZE;
+  m_data_crcs.resize(block_count);
+}
+
+template <uint8_t _b>
+uint64_t BitVector<_b>::size() const {
+  return m_size;
+}
+
+template <uint8_t _b>
+const bufferlist& BitVector<_b>::get_data() const {
+  return m_data;
+}
+
+template <uint8_t _b>
+void BitVector<_b>::compute_index(uint64_t offset, uint64_t *index, uint64_t *shift) {
+  *index = offset / ELEMENTS_PER_BLOCK;
+  *shift = ((ELEMENTS_PER_BLOCK - 1) - (offset % ELEMENTS_PER_BLOCK)) * _b;
+}
+
+template <uint8_t _b>
+void BitVector<_b>::encode_header(bufferlist& bl) const {
+  bufferlist header_bl;
+  ENCODE_START(1, 1, header_bl);
+  ::encode(m_size, header_bl);
+  ENCODE_FINISH(header_bl);
+  m_header_crc = header_bl.crc32c(0);
+
+  ::encode(header_bl, bl);
+}
+
+template <uint8_t _b>
+void BitVector<_b>::decode_header(bufferlist::iterator& it) {
+  bufferlist header_bl;
+  ::decode(header_bl, it);
+
+  bufferlist::iterator header_it = header_bl.begin();
+  uint64_t size;
+  DECODE_START(1, header_it);
+  ::decode(size, header_it);
+  DECODE_FINISH(header_it);
+
+  resize(size);
+  m_header_crc = header_bl.crc32c(0);
+}
+
+template <uint8_t _b>
+uint64_t BitVector<_b>::get_header_length() const {
+  // 4 byte bl length, 6 byte encoding header, 8 byte size
+  return 18;
+}
+
+template <uint8_t _b>
+void BitVector<_b>::encode_data(bufferlist& bl, uint64_t byte_offset,
+				uint64_t byte_length) const {
+  assert(byte_offset % BLOCK_SIZE == 0);
+  assert(byte_offset + byte_length == m_data.length() ||
+	 byte_length % BLOCK_SIZE == 0);
+
+  uint64_t end_offset = byte_offset + byte_length;
+  while (byte_offset < end_offset) {
+    uint64_t len = MIN(BLOCK_SIZE, end_offset - byte_offset);
+
+    bufferlist bit;
+    bit.substr_of(m_data, byte_offset, len);
+    m_data_crcs[byte_offset / BLOCK_SIZE] = bit.crc32c(0);
+
+    bl.claim_append(bit);
+    byte_offset += BLOCK_SIZE;
+  }
+}
+
+template <uint8_t _b>
+void BitVector<_b>::decode_data(bufferlist::iterator& it, uint64_t byte_offset) {
+  assert(byte_offset % BLOCK_SIZE == 0);
+  if (it.end()) {
+    return;
+  }
+
+  uint64_t end_offset = byte_offset + it.get_remaining();
+  if (end_offset > m_data.length()) {
+    throw buffer::end_of_buffer();
+  }
+
+  bufferlist data;
+  if (byte_offset > 0) {
+    data.substr_of(m_data, 0, byte_offset);
+  }
+
+  while (byte_offset < end_offset) {
+    uint64_t len = MIN(BLOCK_SIZE, end_offset - byte_offset);
+
+    bufferptr ptr;
+    it.copy_deep(len, ptr);
+
+    bufferlist bit;
+    bit.append(ptr);
+    if (m_crc_enabled &&
+	m_data_crcs[byte_offset / BLOCK_SIZE] != bit.crc32c(0)) {
+      throw buffer::malformed_input("invalid data block CRC");
+    }
+    data.append(bit);
+    byte_offset += bit.length();
+  }
+
+  if (m_data.length() > end_offset) {
+    bufferlist tail;
+    tail.substr_of(m_data, end_offset, m_data.length() - end_offset);
+    data.append(tail);
+  }
+  assert(data.length() == m_data.length());
+  data.swap(m_data);
+}
+
+template <uint8_t _b>
+void BitVector<_b>::get_data_extents(uint64_t offset, uint64_t length,
+				     uint64_t *byte_offset,
+				     uint64_t *byte_length) const {
+  // read BLOCK_SIZE-aligned chunks
+  assert(length > 0 && offset + length <= m_size);
+  uint64_t shift;
+  compute_index(offset, byte_offset, &shift);
+  *byte_offset -= (*byte_offset % BLOCK_SIZE);
+
+  uint64_t end_offset;
+  compute_index(offset + length - 1, &end_offset, &shift);
+  end_offset += (BLOCK_SIZE - (end_offset % BLOCK_SIZE));
+  assert(*byte_offset <= end_offset);
+
+  *byte_length = end_offset - *byte_offset;
+  if (*byte_offset + *byte_length > m_data.length()) {
+    *byte_length = m_data.length() - *byte_offset;
+  }
+}
+
+template <uint8_t _b>
+void BitVector<_b>::encode_footer(bufferlist& bl) const {
+  bufferlist footer_bl;
+  if (m_crc_enabled) {
+    ::encode(m_header_crc, footer_bl);
+    ::encode(m_data_crcs, footer_bl);
+  }
+  ::encode(footer_bl, bl);
+}
+
+template <uint8_t _b>
+void BitVector<_b>::decode_footer(bufferlist::iterator& it) {
+  bufferlist footer_bl;
+  ::decode(footer_bl, it);
+
+  m_crc_enabled = (footer_bl.length() > 0);
+  if (m_crc_enabled) {
+    bufferlist::iterator footer_it = footer_bl.begin();
+
+    __u32 header_crc;
+    ::decode(header_crc, footer_it);
+    if (m_header_crc != header_crc) {
+      throw buffer::malformed_input("incorrect header CRC");
+    }
+
+    uint64_t block_count = (m_data.length() + BLOCK_SIZE - 1) / BLOCK_SIZE;
+    ::decode(m_data_crcs, footer_it);
+    if (m_data_crcs.size() != block_count) {
+      throw buffer::malformed_input("invalid data block CRCs");
+    }
+  }
+}
+
+template <uint8_t _b>
+uint64_t BitVector<_b>::get_footer_offset() const {
+  return get_header_length() + m_data.length();
+}
+
+template <uint8_t _b>
+void BitVector<_b>::encode(bufferlist& bl) const {
+  encode_header(bl);
+  encode_data(bl, 0, m_data.length());
+  encode_footer(bl);
+}
+
+template <uint8_t _b>
+void BitVector<_b>::decode(bufferlist::iterator& it) {
+  decode_header(it);
+
+  bufferlist data_bl;
+  if (m_data.length() > 0) {
+    it.copy(m_data.length(), data_bl);
+  }
+
+  decode_footer(it);
+
+  bufferlist::iterator data_it = data_bl.begin();
+  decode_data(data_it, 0);
+}
+
+template <uint8_t _b>
+void BitVector<_b>::dump(Formatter *f) const {
+  f->dump_unsigned("size", m_size);
+  f->open_array_section("bit_table");
+  for (unsigned i = 0; i < m_data.length(); ++i) {
+    f->dump_format("byte", "0x%02hhX", m_data[i]);
+  }
+  f->close_section();
+}
+
+template <uint8_t _b>
+bool BitVector<_b>::operator==(const BitVector &b) const {
+  return (this->m_size == b.m_size && this->m_data == b.m_data);
+}
+
+template <uint8_t _b>
+typename BitVector<_b>::Reference BitVector<_b>::operator[](uint64_t offset) {
+  uint64_t index;
+  uint64_t shift;
+  compute_index(offset, &index, &shift);
+
+  bufferlist::iterator data_iterator(m_data.begin());
+  data_iterator.seek(index);
+  return Reference(std::move(data_iterator), shift);
+}
+
+template <uint8_t _b>
+typename BitVector<_b>::ConstReference BitVector<_b>::operator[](uint64_t offset) const {
+  uint64_t index;
+  uint64_t shift;
+  compute_index(offset, &index, &shift);
+
+  bufferlist::const_iterator data_iterator(m_data.begin());
+  data_iterator.seek(index);
+  return ConstReference(std::move(data_iterator), shift);
+}
+
+template <uint8_t _b>
+typename BitVector<_b>::Reference& BitVector<_b>::Reference::operator=(uint8_t v) {
+  uint8_t mask = MASK << this->m_shift;
+  char packed_value = (*this->m_data_iterator & ~mask) |
+                      ((v << this->m_shift) & mask);
+  bufferlist::iterator it(this->m_data_iterator);
+  it.copy_in(1, &packed_value, true);
+  return *this;
+}
+
+template <uint8_t _b>
+void BitVector<_b>::generate_test_instances(std::list<BitVector *> &o) {
+  o.push_back(new BitVector());
+
+  BitVector *b = new BitVector();
+  const uint64_t radix = 1 << b->BIT_COUNT;
+  const uint64_t size = 1024;
+
+  b->resize(size);
+  for (uint64_t i = 0; i < size; ++i) {
+    (*b)[i] = rand() % radix;
+  }
+  o.push_back(b);
+}
+
+}
+
+WRITE_CLASS_ENCODER(ceph::BitVector<2>)
+
+template <uint8_t _b>
+inline std::ostream& operator<<(std::ostream& out, const ceph::BitVector<_b> &b)
+{
+  out << "ceph::BitVector<" << _b << ">(size=" << b.size() << ", data="
+      << b.get_data() << ")";
+  return out;
+}
+
+#endif // BIT_VECTOR_HPP