multi_span.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2021 John Wellbelove
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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SOFTWARE.
******************************************************************************/
 
#ifndef ETL_MULTI_SPAN_INCLUDED
#define ETL_MULTI_SPAN_INCLUDED
 
#include "platform.h"
#include "iterator.h"
#include "algorithm.h"
#include "vector.h"
#include "span.h"
 
 
namespace etl
{
  template <typename T>
  class multi_span
  {
  public:
    
    typedef T                                 element_type;
    typedef typename etl::remove_cv<T>::type  value_type;
    typedef size_t                            size_type;
    typedef T&                                reference;
    typedef const T&                          const_reference;
    typedef T*                                pointer;
    typedef const T*                          const_pointer;
 
    typedef etl::span<T>                      span_type;
    typedef etl::span<const span_type>        span_list_type;
 
    //*************************************************************************
    //*************************************************************************
    class iterator : public etl::iterator<ETL_OR_STD::bidirectional_iterator_tag, element_type>
    {
    public:
 
      friend class multi_span;
      friend class const_iterator;
 
      //*****************************************
      ETL_CONSTEXPR14 iterator()
        : p_span_list(ETL_NULLPTR)
        , p_current_span(ETL_NULLPTR)
        , p_value(ETL_NULLPTR)
      {
      }
 
      //*****************************************
      ETL_CONSTEXPR14 iterator(const iterator& other)
        : p_span_list(other.p_span_list)
        , p_current_span(other.p_current_span)
        , p_value(other.p_value)
      {
      }
 
      //*****************************************
      ETL_CONSTEXPR14 iterator& operator =(const iterator& rhs)
      {
        p_span_list    = rhs.p_span_list;
        p_current_span = rhs.p_current_span;
        p_value        = rhs.p_value;
 
        return *this;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 iterator& operator ++()
      {
        if (p_current_span != p_span_list->end())
        {
          ++p_value;
 
          if (p_value == p_current_span->end())
          {
            do
            {
              ++p_current_span;
            } while ((p_current_span != p_span_list->end()) && p_current_span->empty());
 
            if (p_current_span != p_span_list->end())
            {
              p_value = p_current_span->begin();
            }
            else
            {
              p_value = ETL_NULLPTR;
            }
          }
        }
 
        return *this;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 iterator operator ++(int)
      {
        iterator temp = *this;
 
        operator ++();
 
        return temp;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 iterator& operator --()
      {
        if (p_current_span == p_span_list->end())
        {
          --p_current_span;
          p_value = p_current_span->end();
          --p_value;
        }
        else if ((p_current_span != p_span_list->begin()) || (p_value != p_current_span->begin()))
        {
          if (p_value == p_current_span->begin())
          {
            do
            {
              --p_current_span;
            } while ((p_current_span != p_span_list->begin()) && p_current_span->empty());
 
            p_value = p_current_span->end();
            --p_value;
          }
          else
          {
            --p_value;
          }
        }
        else
        {
          p_value = ETL_NULLPTR;
        }
 
        return *this;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 iterator operator --(int)
      {
        iterator temp = *this;
 
        operator --();
 
        return temp;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 reference operator *()
      {
        return *p_value;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 const_reference operator *() const
      {
        return *p_value;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 pointer operator ->()
      {
        return p_value;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 const_pointer operator ->() const
      {
        return p_value;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 friend bool operator ==(const iterator& lhs, const iterator& rhs)
      {
        return (lhs.p_current_span == rhs.p_current_span) && (lhs.p_value == rhs.p_value);
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 friend bool operator !=(const iterator& lhs, const iterator& rhs)
      {
        return !(lhs == rhs);
      }
 
    private:
 
      typedef const span_type*                  span_pointer;
      typedef const span_list_type*             span_list_pointer;
      typedef typename span_list_type::iterator span_list_iterator;
 
      //*****************************************
      ETL_CONSTEXPR14 iterator(const span_list_type& span_list_, span_list_iterator p_current_span_)
        : p_span_list(&span_list_)
        , p_current_span(p_current_span_)
        , p_value(ETL_NULLPTR)
      {
        if (p_current_span != p_span_list->end())
        {
          while ((p_current_span != p_span_list->end()) && p_current_span->empty())
          {
            ++p_current_span;
          }
          
          if (p_current_span != p_span_list->end())
          {
            p_value = p_current_span->begin();
          }
          else
          {
            p_value = ETL_NULLPTR;
          }
        }
      }
 
      span_list_pointer p_span_list;
      span_pointer      p_current_span;
      pointer           p_value;
    };
 
    //*************************************************************************
    //*************************************************************************
    class const_iterator : public etl::iterator<ETL_OR_STD::bidirectional_iterator_tag, const element_type>
    {
    public:
 
      friend class multi_span;
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator()
        : p_span_list(ETL_NULLPTR)
        , p_current_span(ETL_NULLPTR)
        , p_value(ETL_NULLPTR)
      {
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator(const const_iterator& other)
        : p_span_list(other.p_span_list)
        , p_current_span(other.p_current_span)
        , p_value(other.p_value)
      {
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator& operator =(const const_iterator& rhs)
      {
        p_span_list    = rhs.p_span_list;
        p_current_span = rhs.p_current_span;
        p_value        = rhs.p_value;
 
        return *this;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator(const etl::multi_span<T>::iterator& other)
        : p_span_list(other.p_span_list)
        , p_current_span(other.p_current_span)
        , p_value(other.p_value)
      {
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator& operator =(const etl::multi_span<T>::iterator& rhs)
      {
        p_span_list    = rhs.p_span_list;
        p_current_span = rhs.p_current_span;
        p_value        = rhs.p_value;
 
        return *this;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator& operator ++()
      {
        if (p_current_span != p_span_list->end())
        {
          ++p_value;
 
          if (p_value == p_current_span->end())
          {
            do
            {
              ++p_current_span;
            } while ((p_current_span != p_span_list->end()) && p_current_span->empty());
 
            if (p_current_span != p_span_list->end())
            {
              p_value = p_current_span->begin();
            }
            else
            {
              p_value = ETL_NULLPTR;
            }
          }
        }
 
        return *this;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator operator ++(int)
      {
        const_iterator temp = *this;
 
        operator ++();
 
        return temp;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator& operator --()
      {
        if (p_current_span == p_span_list->end())
        {
          --p_current_span;
          p_value = p_current_span->end();
          --p_value;
        }
        else if ((p_current_span != p_span_list->begin()) || (p_value != p_current_span->begin()))
        {
          if (p_value == p_current_span->begin())
          {
            do
            {
              --p_current_span;
            } while ((p_current_span != p_span_list->begin()) && p_current_span->empty());
 
            p_value = p_current_span->end();
            --p_value;
          }
          else
          {
            --p_value;
          }
        }
        else
        {
          p_value = ETL_NULLPTR;
        }
 
        return *this;
      }
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator operator --(int)
      {
        const_iterator temp = *this;
 
        operator --();
 
        return temp;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 const_reference operator *() const
      {
        return *p_value;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 const_pointer operator ->() const
      {
        return p_value;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 friend bool operator ==(const const_iterator& lhs, const const_iterator& rhs)
      {
        return (lhs.p_current_span == rhs.p_current_span) && (lhs.p_value == rhs.p_value);
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 friend bool operator !=(const const_iterator& lhs, const const_iterator& rhs)
      {
        return !(lhs == rhs);
      }
 
    private:
 
      typedef const span_type*                        span_pointer;
      typedef const span_list_type*                   span_list_pointer;
      typedef const typename span_list_type::iterator span_list_iterator;
 
      //*****************************************
      ETL_CONSTEXPR14 const_iterator(const span_list_type& span_list_, span_list_iterator p_current_span_)
        : p_span_list(&span_list_)
        , p_current_span(p_current_span_)
        , p_value(ETL_NULLPTR)
      {
        if (p_current_span != p_span_list->end())
        {
          while ((p_current_span != p_span_list->end()) && p_current_span->empty())
          {
            ++p_current_span;
          }
 
          if (p_current_span != p_span_list->end())
          {
            p_value = p_current_span->begin();
          }
          else
          {
            p_value = ETL_NULLPTR;
          }
        }
      }
 
      span_list_pointer p_span_list;
      span_pointer      p_current_span;
      const_pointer     p_value;
    };
 
    typedef ETL_OR_STD::reverse_iterator<iterator>       reverse_iterator;
    typedef ETL_OR_STD::reverse_iterator<const_iterator> const_reverse_iterator;
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 multi_span(span_list_type span_list_)
      : span_list(span_list_)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TContainer>
    ETL_CONSTEXPR14 multi_span(TContainer& a) ETL_NOEXCEPT
      : span_list(a.data(), a.data() + a.size())
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TContainer>
    ETL_CONSTEXPR14 multi_span(const TContainer& a) ETL_NOEXCEPT
      : span_list(a.data(), a.data() + a.size())
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TIterator>
    ETL_CONSTEXPR14 multi_span(TIterator begin_, TIterator end_)
      : span_list(etl::to_address(begin_), etl::distance(begin_, end_))
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TIterator>
    ETL_CONSTEXPR14 multi_span(TIterator begin_, size_t length_)
      : span_list(etl::to_address(begin_), length_)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 multi_span(const multi_span& other)
      : span_list(other.span_list)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 multi_span& operator =(const multi_span & other)
    {
      span_list = other.span_list;
 
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 iterator begin() const
    {
      return iterator(span_list, span_list.begin());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 const_iterator cbegin() const
    {
      return const_iterator(span_list, span_list.cbegin());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 iterator end() const
    {
      return iterator(span_list, span_list.end());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 const_iterator cend() const
    {
      return const_iterator(span_list, span_list.cend());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 reverse_iterator rbegin() const
    {
      return reverse_iterator(end());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 reverse_iterator crbegin() const
    {
      return const_reverse_iterator(cend());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 reverse_iterator rend() const
    {
      return reverse_iterator(begin());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 const_reverse_iterator crend() const
    {
      return const_reverse_iterator(cbegin());
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 reference operator[](size_t i) const
    {      
      // Find the span in the span list.
      size_t number_of_spans = span_list.size();
 
      size_t index = 0;
 
      while ((i >= span_list[index].size()) && (index < number_of_spans))
      {
        i -= span_list[index].size();
        ++index;
      }
 
      return span_list[index][i];
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t size() const ETL_NOEXCEPT
    {
      size_t total_n_spans = 0U;
 
      for (typename span_list_type::iterator itr = span_list.begin();
           itr != span_list.end(); 
           ++itr)
      {
        total_n_spans += itr->size();
      }
 
      return total_n_spans;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool empty() const ETL_NOEXCEPT
    {
      if (span_list.empty())
      {
        return true;
      }
      else
      {
        return size() == 0U;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t size_bytes() const ETL_NOEXCEPT
    {
      size_t total_n_spans_bytes = 0U;
 
      for (typename span_list_type::iterator itr = span_list.begin(); 
           itr != span_list.end(); 
           ++itr)
      {
        total_n_spans_bytes += itr->size_bytes();
      }
 
      return total_n_spans_bytes;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_t size_spans() const ETL_NOEXCEPT
    {
      return span_list.size();
    }
 
  private:
 
    span_list_type span_list;
  };
}
 
#endif