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Diffstat (limited to 'gdb/common/array-view.h')
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1 files changed, 0 insertions, 259 deletions
diff --git a/gdb/common/array-view.h b/gdb/common/array-view.h deleted file mode 100644 index ad7933b..0000000 --- a/gdb/common/array-view.h +++ /dev/null @@ -1,259 +0,0 @@ -/* Copyright (C) 2017-2019 Free Software Foundation, Inc. - - This file is part of GDB. - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 3 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see <http://www.gnu.org/licenses/>. */ - -#ifndef COMMON_ARRAY_VIEW_H -#define COMMON_ARRAY_VIEW_H - -#include "traits.h" -#include <type_traits> - -/* An array_view is an abstraction that provides a non-owning view - over a sequence of contiguous objects. - - A way to put it is that array_view is to std::vector (and - std::array and built-in arrays with rank==1) like std::string_view - is to std::string. - - The main intent of array_view is to use it as function input - parameter type, making it possible to pass in any sequence of - contiguous objects, irrespective of whether the objects live on the - stack or heap and what actual container owns them. Implicit - construction from the element type is supported too, making it easy - to call functions that expect an array of elements when you only - have one element (usually on the stack). For example: - - struct A { .... }; - void function (gdb::array_view<A> as); - - std::vector<A> std_vec = ...; - std::array<A, N> std_array = ...; - A array[] = {...}; - A elem; - - function (std_vec); - function (std_array); - function (array); - function (elem); - - Views can be either mutable or const. A const view is simply - created by specifying a const T as array_view template parameter, - in which case operator[] of non-const array_view objects ends up - returning const references. Making the array_view itself const is - analogous to making a pointer itself be const. I.e., disables - re-seating the view/pointer. - - Since array_view objects are small (pointer plus size), and - designed to be trivially copyable, they should generally be passed - around by value. - - You can find unit tests covering the whole API in - unittests/array-view-selftests.c. */ - -namespace gdb { - -template <typename T> -class array_view -{ - /* True iff decayed T is the same as decayed U. E.g., we want to - say that 'T&' is the same as 'const T'. */ - template <typename U> - using IsDecayedT = typename std::is_same<typename std::decay<T>::type, - typename std::decay<U>::type>; - - /* True iff decayed T is the same as decayed U, and 'U *' is - implicitly convertible to 'T *'. This is a requirement for - several methods. */ - template <typename U> - using DecayedConvertible = gdb::And<IsDecayedT<U>, - std::is_convertible<U *, T *>>; - -public: - using value_type = T; - using reference = T &; - using const_reference = const T &; - using size_type = size_t; - - /* Default construction creates an empty view. */ - constexpr array_view () noexcept - : m_array (nullptr), m_size (0) - {} - - /* Create an array view over a single object of the type of an - array_view element. The created view as size==1. This is - templated on U to allow constructing a array_view<const T> over a - (non-const) T. The "convertible" requirement makes sure that you - can't create an array_view<T> over a const T. */ - template<typename U, - typename = Requires<DecayedConvertible<U>>> - constexpr array_view (U &elem) noexcept - : m_array (&elem), m_size (1) - {} - - /* Same as above, for rvalue references. */ - template<typename U, - typename = Requires<DecayedConvertible<U>>> - constexpr array_view (U &&elem) noexcept - : m_array (&elem), m_size (1) - {} - - /* Create an array view from a pointer to an array and an element - count. */ - template<typename U, - typename = Requires<DecayedConvertible<U>>> - constexpr array_view (U *array, size_t size) noexcept - : m_array (array), m_size (size) - {} - - /* Create an array view from a range. This is templated on both U - an V to allow passing in a mix of 'const T *' and 'T *'. */ - template<typename U, typename V, - typename = Requires<DecayedConvertible<U>>, - typename = Requires<DecayedConvertible<V>>> - constexpr array_view (U *begin, V *end) noexcept - : m_array (begin), m_size (end - begin) - {} - - /* Create an array view from an array. */ - template<typename U, size_t Size, - typename = Requires<DecayedConvertible<U>>> - constexpr array_view (U (&array)[Size]) noexcept - : m_array (array), m_size (Size) - {} - - /* Create an array view from a contiguous container. E.g., - std::vector and std::array. */ - template<typename Container, - typename = Requires<gdb::Not<IsDecayedT<Container>>>, - typename - = Requires<std::is_convertible - <decltype (std::declval<Container> ().data ()), - T *>>, - typename - = Requires<std::is_convertible - <decltype (std::declval<Container> ().size ()), - size_type>>> - constexpr array_view (Container &&c) noexcept - : m_array (c.data ()), m_size (c.size ()) - {} - - /* Observer methods. Some of these can't be constexpr until we - require C++14. */ - /*constexpr14*/ T *data () noexcept { return m_array; } - constexpr const T *data () const noexcept { return m_array; } - - /*constexpr14*/ T *begin () noexcept { return m_array; } - constexpr const T *begin () const noexcept { return m_array; } - - /*constexpr14*/ T *end () noexcept { return m_array + m_size; } - constexpr const T *end () const noexcept { return m_array + m_size; } - - /*constexpr14*/ reference operator[] (size_t index) noexcept - { return m_array[index]; } - constexpr const_reference operator[] (size_t index) const noexcept - { return m_array[index]; } - - constexpr size_type size () const noexcept { return m_size; } - constexpr bool empty () const noexcept { return m_size == 0; } - - /* Slice an array view. */ - - /* Return a new array view over SIZE elements starting at START. */ - constexpr array_view<T> slice (size_type start, size_type size) const noexcept - { return {m_array + start, size}; } - - /* Return a new array view over all the elements after START, - inclusive. */ - constexpr array_view<T> slice (size_type start) const noexcept - { return {m_array + start, size () - start}; } - -private: - T *m_array; - size_type m_size; -}; - -/* Compare LHS and RHS for (deep) equality. That is, whether LHS and - RHS have the same sizes, and whether each pair of elements of LHS - and RHS at the same position compares equal. */ - -template <typename T> -bool -operator== (const gdb::array_view<T> &lhs, const gdb::array_view<T> &rhs) -{ - if (lhs.size () != rhs.size ()) - return false; - - for (size_t i = 0; i < lhs.size (); i++) - if (!(lhs[i] == rhs[i])) - return false; - - return true; -} - -/* Compare two array_views for inequality. */ - -template <typename T> -bool -operator!= (const gdb::array_view<T> &lhs, const gdb::array_view<T> &rhs) -{ - return !(lhs == rhs); -} - -/* Create an array view from a pointer to an array and an element - count. - - This is useful as alternative to constructing an array_view using - brace initialization when the size variable you have handy is of - signed type, since otherwise without an explicit cast the code - would be ill-formed. - - For example, with: - - extern void foo (int, int, gdb::array_view<value *>); - - value *args[2]; - int nargs; - foo (1, 2, {values, nargs}); - - You'd get: - - source.c:10: error: narrowing conversion of ‘nargs’ from ‘int’ to - ‘size_t {aka long unsigned int}’ inside { } [-Werror=narrowing] - - You could fix it by writing the somewhat distracting explicit cast: - - foo (1, 2, {values, (size_t) nargs}); - - Or by instantiating an array_view explicitly: - - foo (1, 2, gdb::array_view<value *>(values, nargs)); - - Or, better, using make_array_view, which has the advantage of - inferring the arrav_view element's type: - - foo (1, 2, gdb::make_array_view (values, nargs)); -*/ - -template<typename U> -constexpr inline array_view<U> -make_array_view (U *array, size_t size) noexcept -{ - return {array, size}; -} - -} /* namespace gdb */ - -#endif |