array_view.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2017 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
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******************************************************************************/
 
#ifndef ETL_ARRAY_VIEW_INCLUDED
#define ETL_ARRAY_VIEW_INCLUDED
 
#include "platform.h"
#include "memory.h"
#include "array.h"
#include "iterator.h"
#include "error_handler.h"
#include "exception.h"
#include "nullptr.h"
#include "hash.h"
#include "algorithm.h"
#include "type_traits.h"
 
#if ETL_USING_STL && ETL_USING_CPP11
#include <array>
#endif

 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  class array_view_exception : public exception
  {
  public:
 
    array_view_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
      : exception(reason_, file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class array_view_bounds : public array_view_exception
  {
  public:
 
    array_view_bounds(string_type file_name_, numeric_type line_number_)
      : array_view_exception(ETL_ERROR_TEXT("array_view:bounds", ETL_ARRAY_VIEW_FILE_ID"A"), file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class array_view_uninitialised : public array_view_exception
  {
  public:
 
    array_view_uninitialised(string_type file_name_, numeric_type line_number_)
      : array_view_exception(ETL_ERROR_TEXT("array_view:uninitialised", ETL_ARRAY_VIEW_FILE_ID"B"), file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class array_view
  {
  public:
 
    typedef T        value_type;
    typedef size_t   size_type;
    typedef const T& const_reference;
    typedef const T* const_pointer;
    typedef const T* const_iterator;
    typedef ETL_OR_STD::reverse_iterator<const_iterator> const_reverse_iterator;
 
#if defined(ETL_ARRAY_VIEW_IS_MUTABLE)
    typedef T* pointer;
    typedef T& reference;
    typedef T* iterator;
    typedef ETL_OR_STD::reverse_iterator<iterator> reverse_iterator;
#else
    typedef const_pointer   pointer;
    typedef const_reference reference;
    typedef const_pointer   iterator;
    typedef const_reverse_iterator reverse_iterator;
#endif
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR array_view() ETL_NOEXCEPT
      : mbegin(ETL_NULLPTR),
        mend(ETL_NULLPTR)
    {
    }
 
#if ETL_USING_CPP11
    //*************************************************************************
    //*************************************************************************
    template <typename U, size_t Size, typename = typename etl::enable_if<etl::is_same<etl::remove_cv_t<T>, etl::remove_cv_t<U>>::value, void>::type>
    ETL_CONSTEXPR array_view(etl::array<U, Size>& a) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename U, size_t Size, typename = typename etl::enable_if<etl::is_same<etl::remove_cv_t<T>, etl::remove_cv_t<U>>::value, void>::type>
    ETL_CONSTEXPR array_view(const etl::array<U, Size>& a) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
#else
    //*************************************************************************
    //*************************************************************************
    template <typename U, size_t Size>
    ETL_CONSTEXPR array_view(etl::array<U, Size>& a, typename etl::enable_if<etl::is_same<typename etl::remove_cv<T>::type, typename etl::remove_cv<U>::type>::value, void>::type* = 0) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename U, size_t Size>
    ETL_CONSTEXPR array_view(const etl::array<U, Size>& a, typename etl::enable_if<etl::is_same<typename etl::remove_cv<T>::type, typename etl::remove_cv<U>::type>::value, void>::type* = 0) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
#endif
 
#if ETL_USING_STL && ETL_USING_CPP11
    //*************************************************************************
    //*************************************************************************
    template <typename U, size_t Size, typename = typename etl::enable_if<etl::is_same<etl::remove_cv_t<T>, etl::remove_cv_t<U>>::value, void>::type>
    ETL_CONSTEXPR array_view(std::array<U, Size>& a) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename U, size_t Size, typename = typename etl::enable_if<etl::is_same<etl::remove_cv_t<T>, etl::remove_cv_t<U>>::value, void>::type>
    ETL_CONSTEXPR array_view(const std::array<U, Size>& a) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
#endif
 
#if ETL_USING_CPP11
    //*************************************************************************
    //*************************************************************************
    template <typename TContainer, typename = typename etl::enable_if<!etl::is_pointer<etl::remove_reference_t<TContainer>>::value &&
                                                                      !etl::is_array<etl::remove_reference_t<TContainer>>::value &&
                                                                      etl::is_same<etl::remove_cv_t<T>, etl::remove_cv_t<typename etl::remove_reference_t<TContainer>::value_type>>::value, void>::type>
      ETL_CONSTEXPR array_view(TContainer&& a) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
#else
    //*************************************************************************
    //*************************************************************************
    template <typename TContainer>
    ETL_CONSTEXPR array_view(TContainer& a, typename etl::enable_if<!etl::is_pointer<typename etl::remove_reference<TContainer>::type>::value &&
                                                                    !etl::is_array<TContainer>::value &&
                                                                    etl::is_same<typename etl::remove_cv<T>::type, typename etl::remove_cv<typename etl::remove_reference<TContainer>::type::value_type>::type>::value, void>::type* = 0) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TContainer>
    ETL_CONSTEXPR array_view(const TContainer& a, typename etl::enable_if<!etl::is_pointer<typename etl::remove_reference<TContainer>::type>::value &&
                                                                          !etl::is_array<TContainer>::value &&
                                                                          etl::is_same<typename etl::remove_cv<T>::type, typename etl::remove_cv<typename etl::remove_reference<TContainer>::type::value_type>::type>::value, void>::type* = 0) ETL_NOEXCEPT
      : mbegin(a.data())
      , mend(a.data() + a.size())
    {
    }
#endif
 
    //*************************************************************************
    //*************************************************************************
    template <typename TIterator>
    ETL_CONSTEXPR array_view(const TIterator begin_, const TIterator end_) ETL_NOEXCEPT
      : mbegin(etl::to_address(begin_)),
        mend(etl::to_address(begin_) + etl::distance(begin_, end_))
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TIterator,
              typename TSize>
    ETL_CONSTEXPR array_view(const TIterator begin_, const TSize size_) ETL_NOEXCEPT
      : mbegin(etl::to_address(begin_)),
        mend(etl::to_address(begin_) + size_)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    template<size_t Array_Size>
    ETL_CONSTEXPR array_view(T(&begin_)[Array_Size]) ETL_NOEXCEPT
      : mbegin(begin_),
        mend(begin_ + Array_Size)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR array_view(const array_view& other) ETL_NOEXCEPT
      : mbegin(other.mbegin),
        mend(other.mend)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    reference front()
    {
      return *mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    const_reference front() const
    {
      return *mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    reference back()
    {
      return *(mend - 1);
    }
 
    //*************************************************************************
    //*************************************************************************
    const_reference back() const
    {
      return *(mend - 1);
    }
 
    //*************************************************************************
    //*************************************************************************
    pointer data() ETL_NOEXCEPT
    {
      return mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    const_pointer data() const ETL_NOEXCEPT
    {
      return mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    iterator begin() ETL_NOEXCEPT
    {
      return mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    const_iterator begin() const ETL_NOEXCEPT
    {
      return mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    const_iterator cbegin() const ETL_NOEXCEPT
    {
      return mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    iterator end() ETL_NOEXCEPT
    {
      return mend;
    }
 
    //*************************************************************************
    //*************************************************************************
    const_iterator end() const ETL_NOEXCEPT
    {
      return mend;
    }
 
    //*************************************************************************
    // Returns a const iterator to the end of the array.
    //*************************************************************************
    const_iterator cend() const ETL_NOEXCEPT
    {
      return mend;
    }
 
    //*************************************************************************
    // Returns an reverse iterator to the reverse beginning of the array.
    //*************************************************************************
    reverse_iterator rbegin() ETL_NOEXCEPT
    {
      return reverse_iterator(mend);
    }
 
    //*************************************************************************
    //*************************************************************************
    const_reverse_iterator rbegin() const ETL_NOEXCEPT
    {
      return const_reverse_iterator(mend);
    }
 
    //*************************************************************************
    //*************************************************************************
    const_reverse_iterator crbegin() const ETL_NOEXCEPT
    {
      return const_reverse_iterator(mend);
    }
 
    //*************************************************************************
    //*************************************************************************
    reverse_iterator rend() ETL_NOEXCEPT
    {
      return reverse_iterator(mbegin);
    }
 
    //*************************************************************************
    //*************************************************************************
    const_reverse_iterator rend() const ETL_NOEXCEPT
    {
      return const_reverse_iterator(mbegin);
    }
 
    //*************************************************************************
    //*************************************************************************
    const_reverse_iterator crend() const ETL_NOEXCEPT
    {
      return const_reverse_iterator(mbegin);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR bool empty() const ETL_NOEXCEPT
    {
      return (mbegin == mend);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR size_t size() const ETL_NOEXCEPT
    {
      return static_cast<size_t>(mend - mbegin);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR size_t max_size() const ETL_NOEXCEPT
    {
      return size();
    }
 
    //*************************************************************************
    //*************************************************************************
    array_view& operator=(const array_view& other) ETL_NOEXCEPT
    {
      mbegin = other.mbegin;
      mend   = other.mend;
      return *this;
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TIterator>
    void assign(const TIterator begin_, const TIterator end_)
    {
      mbegin = etl::to_address(begin_);
      mend   = etl::to_address(begin_) + etl::distance(begin_, end_);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TIterator,
              typename TSize>
    void assign(const TIterator begin_, const TSize size_)
    {
      mbegin = etl::to_address(begin_);
      mend   = etl::to_address(begin_) + size_;
    }
 
#if defined(ETL_ARRAY_VIEW_IS_MUTABLE)
    //*************************************************************************
    //*************************************************************************
    reference operator[](const size_t i) ETL_NOEXCEPT
    {
      return mbegin[i];
    }
#endif
 
    //*************************************************************************
    //*************************************************************************
    const_reference operator[](const size_t i) const ETL_NOEXCEPT
    {
      return mbegin[i];
    }
 
#if defined(ETL_ARRAY_VIEW_IS_MUTABLE)
    //*************************************************************************
    //*************************************************************************
    reference at(const size_t i)
    {
      ETL_ASSERT((mbegin != ETL_NULLPTR && mend != ETL_NULLPTR), ETL_ERROR(array_view_uninitialised));
      ETL_ASSERT(i < size(), ETL_ERROR(array_view_bounds));
      return mbegin[i];
    }
#endif
 
    //*************************************************************************
    //*************************************************************************
    const_reference at(const size_t i) const
    {
      ETL_ASSERT((mbegin != ETL_NULLPTR && mend != ETL_NULLPTR), ETL_ERROR(array_view_uninitialised));
      ETL_ASSERT(i < size(), ETL_ERROR(array_view_bounds));
      return mbegin[i];
    }
 
    //*************************************************************************
    //*************************************************************************
    void swap(array_view& other) ETL_NOEXCEPT
    {
      using ETL_OR_STD::swap; // Allow ADL
 
      swap(mbegin, other.mbegin);
      swap(mend, other.mend);
    }
 
    //*************************************************************************
    //*************************************************************************
    void remove_prefix(const size_type n) ETL_NOEXCEPT
    {
        if (n < size())
            mbegin += n;
        else
            mbegin = mend;
    }
 
    //*************************************************************************
    //*************************************************************************
    void remove_suffix(const size_type n) ETL_NOEXCEPT
    {
        if (n < size())
            mend -= n;
        else
            mend = mbegin;
    }
 
    //*************************************************************************
    //*************************************************************************
    void fill(const T& value)
    {
      etl::fill(begin(), end(), value);
    }
 
    //*************************************************************************
    //*************************************************************************
    friend bool operator == (const array_view<T>& lhs, const array_view<T>& rhs)
    {
      return (lhs.size() == rhs.size()) &&
             etl::equal(lhs.begin(), lhs.end(), rhs.begin());
    }
 
    //*************************************************************************
    //*************************************************************************
    friend bool operator != (const array_view<T>& lhs, const array_view<T>& rhs)
    {
      return !(lhs == rhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    friend bool operator < (const array_view<T>& lhs, const array_view<T>& rhs)
    {
      return etl::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
    }
 
    //*************************************************************************
    //*************************************************************************
    friend bool operator > (const array_view<T>& lhs, const array_view<T>& rhs)
    {
      return rhs < lhs;
    }
 
    //*************************************************************************
    //*************************************************************************
    friend bool operator <= (const array_view<T>& lhs, const array_view<T>& rhs)
    {
      return !(lhs > rhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    friend bool operator >= (const array_view<T>& lhs, const array_view<T>& rhs)
    {
      return !(lhs < rhs);
    }
 
  private:
 
    pointer mbegin;
    pointer mend;
  };
 
  //*************************************************************************
  //*************************************************************************
#if ETL_USING_CPP17
  template <typename TArray>
  array_view(TArray& a) 
    -> array_view<typename TArray::value_type>;
 
  template <typename TIterator>
  array_view(const TIterator begin_, const TIterator end_)
    -> array_view<etl::remove_pointer_t<TIterator>>;
 
  template <typename TIterator,
            typename TSize>
  array_view(const TIterator begin_, const TSize size_)
    -> array_view<etl::remove_pointer_t<TIterator>>;
#endif  
 
  //*************************************************************************
  //*************************************************************************
#if ETL_USING_8BIT_TYPES
  template <typename T>
  struct hash<etl::array_view<T> >
  {
    size_t operator()(const etl::array_view<T>& view) const
    {
      return etl::private_hash::generic_hash<size_t>(reinterpret_cast<const uint8_t*>(view.data()),
                                                     reinterpret_cast<const uint8_t*>(view.data() + view.size()));
    }
  };
#endif
}
 
//*************************************************************************
//*************************************************************************
template <typename T>
void swap(etl::array_view<T>& lhs, etl::array_view<T>& rhs) ETL_NOEXCEPT
{
  lhs.swap(rhs);
}
 
#endif