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Diffstat (limited to 'contrib/epee/include/span_view.h')
-rw-r--r-- | contrib/epee/include/span_view.h | 174 |
1 files changed, 0 insertions, 174 deletions
diff --git a/contrib/epee/include/span_view.h b/contrib/epee/include/span_view.h deleted file mode 100644 index 33c538d37..000000000 --- a/contrib/epee/include/span_view.h +++ /dev/null @@ -1,174 +0,0 @@ -// Copyright (c) 2017, The Monero Project -// -// All rights reserved. -// -// Redistribution and use in source and binary forms, with or without modification, are -// permitted provided that the following conditions are met: -// -// 1. Redistributions of source code must retain the above copyright notice, this list of -// conditions and the following disclaimer. -// -// 2. Redistributions in binary form must reproduce the above copyright notice, this list -// of conditions and the following disclaimer in the documentation and/or other -// materials provided with the distribution. -// -// 3. Neither the name of the copyright holder nor the names of its contributors may be -// used to endorse or promote products derived from this software without specific -// prior written permission. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY -// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF -// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL -// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, -// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS -// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, -// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF -// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - -#pragma once - -#include <cstddef> -#include <memory> -#include <type_traits> -#include <utility> - -namespace epee -{ - /*! - \brief Non-owning sequence of data. Does not deep copy - - Inspired by `gsl::span`. This class is intended to be used as a parameter - type for functions that need to take a writable or read-only sequence of - data. Most common cases are `span<char>` and `span<std::uint8_t>`. Using as - a class member is only recommended if clearly documented as not doing a - deep-copy. `std::vector`, `std::string`, `std::array`, and C-arrays are all - easily convertible to this type. - - \note Conversion from C string literal to `view<char>` will include the - NULL-terminator. - \note `view<T>` is an alias for `span<const T>` which is read-only. - \note Never allows derived-to-base pointer conversion; an array of derived - types is not an array of base types. - */ - template<typename T> - class span - { - /* Supporting class types is tricky - the {ptr,len} and {container} - constructors will allow derived-to-base conversions. This is NOT - desireable because an array of derived types is not an array of base - types. It is possible to handle this case, implement when/if needed. */ - static_assert(std::is_integral<T>::value, "only integral values currently for span"); - - // Disables ADL for these calls. - struct get { - // we only accept pointer and size_t return types, so use noexcept aggressively - template<std::size_t N> - static constexpr T* data(T (&src)[N]) noexcept { return src; } - - template<typename C> - static constexpr auto - data(C& src) noexcept(noexcept(src.data())) -> decltype(src.data()) { - return src.data(); - } - - - template<std::size_t N> - static constexpr std::size_t size(T (&)[N]) noexcept { return N; } - - template<typename C> - static constexpr auto - size(const C& src) noexcept(noexcept(src.size())) -> decltype(src.size()) { - return src.size(); - } - }; - - public: - using value_type = T; - using pointer = T*; - using reference = T&; - using iterator = pointer; - using const_iterator = typename std::add_const<value_type>::type *; - - constexpr span() noexcept : ptr(nullptr), len(0) {} - constexpr span(std::nullptr_t) noexcept : span() {} - - constexpr span(T* const src_ptr, const std::size_t src_len) noexcept - : ptr(src_ptr), len(src_len) { - } - - /*! - A `span` is implicitly convertible from any type where `get::data(src)` - returns a pointer convertible to T* and `get::size(src)` returns a - `std::size_t`. This constructor is disabled for all other types. - */ - template< - typename C, - typename U = decltype(get::data(std::declval<C&>())), - typename S = decltype(get::size(std::declval<C&>())), - typename = typename std::enable_if< - // Do not allow proxy iterators, but allow valid cv conversions - std::is_pointer<U>::value && std::is_convertible<U, pointer>::value && - // Prevent underflow/overflow on size storage - std::is_same<S, std::size_t>::value - >::type - > - constexpr span(C&& src) noexcept(noexcept(get::data(src), get::size(src))) - : span(get::data(src), get::size(src)) { - } - - constexpr span(span&&) noexcept = default; - constexpr span(span&) noexcept = default; - constexpr span(const span&) noexcept = default; - span& operator=(const span&) noexcept = default; - - constexpr iterator begin() const noexcept { return ptr; } - constexpr const_iterator cbegin() const noexcept { return ptr; } - - constexpr iterator end() const noexcept { return begin() + size(); } - constexpr const_iterator cend() const noexcept { return cbegin() + size(); } - - constexpr bool empty() const noexcept { return size() == 0; } - constexpr pointer data() const noexcept { return ptr; } - constexpr std::size_t size() const noexcept { return len; } - constexpr std::size_t size_bytes() const noexcept { return size() * sizeof(value_type); } - - private: - T* ptr; - std::size_t len; - }; - - //! A `view` is a `span` over immutable data. See `span` for more info. - template<typename T> - using view = span<typename std::add_const<T>::type>; - - //! \return `src` aliased as a view of type `T`. - template<typename T, typename U> - view<T> view_cast(const span<U>& src) noexcept - { - using normalized = typename std::remove_cv<T>::type; - static_assert( - std::is_same<normalized, char>::value || std::is_same<normalized, std::uint8_t>::value, - "only valid aliasing allowed - char or unsigned char target types" - ); - - static_assert(std::is_integral<U>::value, "only integral source types"); - return {reinterpret_cast<typename std::add_const<T>::type *>(src.data()), src.size_bytes()}; - } - - //! \return `src` aliased as a span of type `T`. - template<typename T, typename U> - span<T> pod_cast(U&& src) noexcept - { - using normalized = typename std::remove_cv<T>::type; - static_assert( - std::is_same<normalized, char>::value || std::is_same<normalized, std::uint8_t>::value, - "only valid aliasing allowed - char or unsigned char target types" - ); - - using decayed = typename std::decay<U>::type; - static_assert(std::is_pod<decayed>::value, "only POD types allowed for conversion"); - static_assert(alignof(decayed) == 1, "only types with 1 byte alignment allowed for conversion"); - return {reinterpret_cast<T*>(std::addressof(src)), sizeof(decayed)}; - } -} |