array_adapters.hpp

#pragma once
#include "base/assert.hpp"


namespace detail
{
  template <class T, class TPtr> class array_impl
  {
  protected:
    TPtr m_p;
    size_t m_size;

  public:
    typedef T value_type;
    typedef T const & const_reference;
    typedef T & reference;

    array_impl(TPtr p, size_t sz) : m_p(p), m_size(sz) {}

    T const & operator[](size_t i) const
    {
      ASSERT_LESS ( i, m_size, () );
      return m_p[i]; 
    }

    T const & back() const
    {
      ASSERT_GREATER ( m_size, 0, () );
      return m_p[m_size-1];
    }

    size_t size() const { return m_size; }

    bool empty() const { return (m_size == 0); }
  };
}

template <class T> class array_read : public detail::array_impl<T, T const *>
{
public:
  array_read(T const * p, size_t sz)
    : detail::array_impl<T, T const *>(p, sz)
  {
  }
};

template <class TCont>
array_read<typename TCont::value_type> make_read_adapter(TCont const & cont)
{
  return array_read<typename TCont::value_type>(cont.empty() ? 0 : &cont[0], cont.size());
}

template <class T> class array_write : public detail::array_impl<T, T *>
{
  size_t m_capacity;

  typedef detail::array_impl<T, T *> base_t;

public:
  template <class TCont> explicit array_write(TCont & cont)
    : detail::array_impl<T, T *>(cont.empty() ? 0 : &cont[0], 0), m_capacity(cont.size())
  {
  }

  void push_back(T const & t)
  {
    ASSERT_LESS ( base_t::m_size, m_capacity, () );
    base_t::m_p[base_t::m_size++] = t;
  }
};