ZBuffer.h

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// this is for emacs file handling -*- mode: c++; indent-tabs-mode: nil -*-

// -- BEGIN LICENSE BLOCK ----------------------------------------------
// This file is part of FZIs ic_workspace.
//
// This program is free software licensed under the LGPL
// (GNU LESSER GENERAL PUBLIC LICENSE Version 3).
// You can find a copy of this license in LICENSE folder in the top
// directory of the source code.
//
// © Copyright 2016 FZI Forschungszentrum Informatik, Karlsruhe, Germany
//
// -- END LICENSE BLOCK ------------------------------------------------

//----------------------------------------------------------------------
//----------------------------------------------------------------------
#ifndef ICL_CORE_Z_BUFFER_H_INCLUDED
#define ICL_CORE_Z_BUFFER_H_INCLUDED

#include <vector>
#include <cassert>
#include <boost/optional.hpp>

namespace icl_core {

template <typename T, typename TCompare = std::less<T> >
class ZBuffer
{
public:
  typedef std::vector<boost::optional<T> > Buffer;
  typedef typename Buffer::size_type size_type;

  explicit ZBuffer(const std::size_t size, const TCompare& cmp = TCompare())
    : m_buffer(size),
      m_cmp(cmp)
  { }

  bool update(const std::size_t pos, const T& value)
  {
    assert(pos < m_buffer.size());
    if (!m_buffer[pos] || m_cmp(value, *m_buffer[pos]))
    {
      m_buffer[pos] = value;
      return true;
    }
    return false;
  }

  void reset() { m_buffer.assign(size); }
  const size_type size() const { return m_buffer.size(); }
  const Buffer& buffer() const { return m_buffer; }
  boost::optional<T> at(const std::size_t pos) const { return m_buffer[pos]; }
  boost::optional<T> operator [] (const std::size_t pos) const { return m_buffer[pos]; }

private:
  Buffer m_buffer;
  TCompare m_cmp;
};

}

#endif