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https://github.com/ETLCPP/etl.git
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332 lines
13 KiB
C++
332 lines
13 KiB
C++
///\file
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/******************************************************************************
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The MIT License(MIT)
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Embedded Template Library.
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https://github.com/ETLCPP/etl
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https://www.etlcpp.com
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Copyright(c) 2020 jwellbelove
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files(the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions :
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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******************************************************************************/
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#ifndef ETL_SPAN_INCLUDED
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#define ETL_SPAN_INCLUDED
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#include "platform.h"
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#include "iterator.h"
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#include "nullptr.h"
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#include "hash.h"
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#include "type_traits.h"
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#include "integral_limits.h"
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#include "memory.h"
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#include "array.h"
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///\defgroup span span
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/// A wrapper for arrays
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///\ingroup containers
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#undef ETL_FILE
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#define ETL_FILE "41"
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namespace etl
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{
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static ETL_CONST_OR_CONSTEXPR size_t dynamic_extent = etl::integral_limits<size_t>::max;
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//***************************************************************************
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/// Array view.
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//***************************************************************************
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template <typename T, const size_t EXTENT = etl::dynamic_extent>
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class span
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{
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public:
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typedef T element_type;
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typedef typename etl::remove_cv<T>::type value_type;
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typedef size_t size_type;
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typedef T& reference;
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typedef const T& const_reference;
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typedef T* pointer;
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typedef const T* const_pointer;
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typedef T* iterator;
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typedef const T* const_iterator;
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typedef ETL_OR_STD::reverse_iterator<iterator> reverse_iterator;
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typedef ETL_OR_STD::reverse_iterator<const_iterator> const_reverse_iterator;
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static ETL_CONST_OR_CONSTEXPR size_t extent = EXTENT;
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//*************************************************************************
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/// Default constructor.
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//*************************************************************************
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ETL_CONSTEXPR span() ETL_NOEXCEPT
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: mbegin(ETL_NULLPTR)
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, mend(ETL_NULLPTR)
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{
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}
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//*************************************************************************
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/// Construct from std::array or etl::array or other type that supports
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/// data() and size() member functions.
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//*************************************************************************
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template <typename TSpan>
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ETL_CONSTEXPR explicit span(TSpan& a) ETL_NOEXCEPT
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: mbegin(a.data())
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, mend(a.data() + a.size())
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{
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}
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//*************************************************************************
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/// Construct from std::array or etl::array or other type that supports
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/// data() and size() member functions.
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//*************************************************************************
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template <typename TSpan>
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ETL_CONSTEXPR explicit span(const TSpan& a) ETL_NOEXCEPT
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: mbegin(a.data())
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, mend(a.data() + a.size())
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{
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}
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//*************************************************************************
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/// Construct from iterators
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//*************************************************************************
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template <typename TIterator>
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ETL_CONSTEXPR span(const TIterator begin_, const TIterator end_)
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: mbegin(etl::addressof(*begin_))
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, mend(etl::addressof(*begin_) + etl::distance(begin_, end_))
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{
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}
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//*************************************************************************
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/// Construct from pointer + size
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//*************************************************************************
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template <typename TIterator, typename TSize>
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ETL_CONSTEXPR span(const TIterator begin_, const TSize size_) ETL_NOEXCEPT
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: mbegin(etl::addressof(*begin_))
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, mend(etl::addressof(*begin_) + size_)
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{
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}
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//*************************************************************************
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/// Construct from C array
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//*************************************************************************
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template<const size_t ARRAY_SIZE>
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ETL_CONSTEXPR explicit span(element_type(&begin_)[ARRAY_SIZE]) ETL_NOEXCEPT
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: mbegin(begin_)
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, mend(begin_ + ARRAY_SIZE)
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{
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}
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//*************************************************************************
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/// Copy constructor
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//*************************************************************************
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ETL_CONSTEXPR span(const span& other) ETL_NOEXCEPT
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: mbegin(other.mbegin)
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, mend(other.mend)
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{
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}
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//*************************************************************************
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/// Returns a reference to the first element.
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//*************************************************************************
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ETL_CONSTEXPR reference front() const ETL_NOEXCEPT
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{
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return *mbegin;
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}
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//*************************************************************************
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/// Returns a reference to the last element.
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//*************************************************************************
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ETL_CONSTEXPR reference back() const ETL_NOEXCEPT
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{
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return *(mend - 1);
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}
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//*************************************************************************
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/// Returns a pointer to the first element of the internal storage.
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//*************************************************************************
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ETL_CONSTEXPR pointer data() const ETL_NOEXCEPT
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{
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return mbegin;
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}
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//*************************************************************************
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/// Returns an iterator to the beginning of the span.
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//*************************************************************************
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ETL_CONSTEXPR iterator begin() const ETL_NOEXCEPT
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{
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return mbegin;
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}
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//*************************************************************************
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/// Returns an iterator to the end of the span.
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//*************************************************************************
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ETL_CONSTEXPR iterator end() const ETL_NOEXCEPT
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{
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return mend;
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}
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//*************************************************************************
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// Returns an reverse iterator to the reverse beginning of the span.
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//*************************************************************************
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ETL_CONSTEXPR reverse_iterator rbegin() const ETL_NOEXCEPT
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{
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return reverse_iterator(mend);
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}
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//*************************************************************************
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/// Returns a reverse iterator to the end of the span.
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//*************************************************************************
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ETL_CONSTEXPR reverse_iterator rend() const ETL_NOEXCEPT
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{
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return reverse_iterator(mbegin);
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}
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//*************************************************************************
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/// Returns <b>true</b> if the span size is zero.
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//*************************************************************************
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ETL_CONSTEXPR bool empty() const ETL_NOEXCEPT
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{
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return (mbegin == mend);
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}
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//*************************************************************************
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/// Returns the size of the span.
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//*************************************************************************
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ETL_CONSTEXPR size_t size() const ETL_NOEXCEPT
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{
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return (mend - mbegin);
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}
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//*************************************************************************
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/// Returns the size of the span in bytes.
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//*************************************************************************
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ETL_CONSTEXPR size_t size_bytes() const ETL_NOEXCEPT
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{
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return sizeof(element_type) * (mend - mbegin);
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}
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//*************************************************************************
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/// Returns the maximum possible size of the span.
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//*************************************************************************
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ETL_CONSTEXPR size_t max_size() const ETL_NOEXCEPT
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{
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return size();
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}
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//*************************************************************************
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/// Assign from a span.
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//*************************************************************************
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ETL_CONSTEXPR span& operator =(const span& other) ETL_NOEXCEPT
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{
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mbegin = other.mbegin;
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mend = other.mend;
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return *this;
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}
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//*************************************************************************
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/// Returns a reference to the indexed value.
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//*************************************************************************
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ETL_CONSTEXPR reference operator[](const size_t i) const
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{
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return mbegin[i];
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}
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//*************************************************************************
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/// Obtains a span that is a view over the first COUNT elements of this span.
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//*************************************************************************
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template <const size_t COUNT>
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ETL_CONSTEXPR etl::span<element_type, COUNT> first() const
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{
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return etl::span<element_type, COUNT>(mbegin, mbegin + COUNT);
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}
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//*************************************************************************
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/// Obtains a span that is a view over the last COUNT elements of this span.
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//*************************************************************************
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template <const size_t COUNT>
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ETL_CONSTEXPR etl::span<element_type, COUNT> last() const
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{
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return etl::span<element_type, COUNT>(mend - COUNT, mend);
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}
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//*************************************************************************
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/// Obtains a span that is a view from OFFSET over the next COUNT elements of this span.
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/// Enabled for COUNT == etl::dynamic_extent
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//*************************************************************************
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template <const size_t OFFSET, const size_t COUNT = etl::dynamic_extent>
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ETL_CONSTEXPR
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typename etl::enable_if<COUNT == etl::dynamic_extent, etl::span<element_type, ((EXTENT != etl::dynamic_extent) ? EXTENT - OFFSET : etl::dynamic_extent)> >::type
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subspan() const
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{
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return etl::span<element_type, ((EXTENT != etl::dynamic_extent) ? EXTENT - OFFSET : etl::dynamic_extent)>(mbegin + OFFSET, mend);
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}
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//*************************************************************************
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/// Obtains a span that is a view from OFFSET over the next COUNT elements of this span.
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/// Enabled for COUNT != etl::dynamic_extent
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//*************************************************************************
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template <const size_t OFFSET, const size_t COUNT = etl::dynamic_extent>
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ETL_CONSTEXPR
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typename etl::enable_if<COUNT != etl::dynamic_extent, etl::span<element_type, COUNT> >::type
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subspan() const
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{
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return etl::span<element_type, COUNT>(mbegin + OFFSET, mbegin + OFFSET + COUNT);
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}
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//*************************************************************************
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/// Obtains a span that is a view from 'offset' over the next 'count' elements of this span.
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//*************************************************************************
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ETL_CONSTEXPR14 etl::span<element_type, etl::dynamic_extent> subspan(size_t offset, size_t count = etl::dynamic_extent) const
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{
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if (count == etl::dynamic_extent)
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{
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return etl::span<element_type, etl::dynamic_extent>(mbegin + offset, mend);
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}
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return etl::span<element_type, etl::dynamic_extent>(mbegin + offset, mbegin + offset + count);
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}
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private:
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element_type* mbegin;
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element_type* mend;
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};
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//*************************************************************************
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/// Hash function.
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//*************************************************************************
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#if ETL_8BIT_SUPPORT
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template <typename T>
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struct hash<etl::span<T> >
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{
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size_t operator()(const etl::span<T>& view) const
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{
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return etl::private_hash::generic_hash<size_t>(reinterpret_cast<const uint8_t*>(&view[0]),
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reinterpret_cast<const uint8_t*>(&view[view.size()]));
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}
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};
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#endif
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}
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#undef ETL_FILE
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#endif
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