340 lines
12 KiB
C
340 lines
12 KiB
C
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///\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) 2014 John Wellbelove
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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_ALIGNMENT_INCLUDED
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#define ETL_ALIGNMENT_INCLUDED
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#include "platform.h"
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#include "type_traits.h"
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#include "static_assert.h"
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#include "error_handler.h"
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#include "exception.h"
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#include <stdint.h>
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///\defgroup alignment alignment
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/// Creates a variable of the specified type at the specified alignment.
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/// \ingroup utilities
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namespace etl
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{
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//***************************************************************************
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/// Exception base for alignment
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//***************************************************************************
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class alignment_exception : public etl::exception
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{
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public:
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alignment_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
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: exception(reason_, file_name_, line_number_)
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{
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}
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};
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//***************************************************************************
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/// Memory misalignment exception.
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//***************************************************************************
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class alignment_error : public alignment_exception
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{
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public:
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alignment_error(string_type file_name_, numeric_type line_number_)
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: alignment_exception(ETL_ERROR_TEXT("alignment:error", ETL_ALIGNMENT_FILE_ID"A"), file_name_, line_number_)
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{
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}
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};
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//*****************************************************************************
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/// Check that 'p' has 'required_alignment'.
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//*****************************************************************************
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inline bool is_aligned(void* p, size_t required_alignment)
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{
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uintptr_t address = reinterpret_cast<uintptr_t>(p);
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return (address % required_alignment) == 0U;
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}
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//*****************************************************************************
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/// Check that 'p' has 'Alignment'.
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//*****************************************************************************
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template <size_t Alignment>
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bool is_aligned(void* p)
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{
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uintptr_t address = reinterpret_cast<uintptr_t>(p);
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return (address % Alignment) == 0U;
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}
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//*****************************************************************************
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/// Check that 'p' has the alignment of 'T'.
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//*****************************************************************************
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template <typename T>
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bool is_aligned(void* p)
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{
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return is_aligned<etl::alignment_of<T>::value>(p);
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}
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namespace private_alignment
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{
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#if ETL_USING_CPP11
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//***************************************************************************
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// Matcher.
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//***************************************************************************
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template <bool Is_Match, size_t Alignment, typename... TRest>
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class type_with_alignment_matcher;
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// Matching alignment.
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template <size_t Alignment, typename T1, typename... TRest>
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class type_with_alignment_matcher<true, Alignment, T1, TRest...>
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{
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public:
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typedef T1 type;
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};
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// Non-matching alignment
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template <size_t Alignment, typename T1, typename T2, typename... TRest>
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class type_with_alignment_matcher <false, Alignment, T1, T2, TRest...>
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{
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public:
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typedef typename type_with_alignment_matcher < Alignment <= etl::alignment_of<T2>::value , Alignment, T2, TRest... > ::type type;
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};
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// Non-matching alignment, none left.
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template <size_t Alignment, typename T1>
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class type_with_alignment_matcher <false, Alignment, T1>
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{
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public:
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typedef char type;
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};
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//***************************************************************************
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// Helper.
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//***************************************************************************
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template <size_t Alignment, typename T1, typename... T>
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class type_with_alignment_helper
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{
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public:
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typedef typename type_with_alignment_matcher<Alignment <= etl::alignment_of<T1>::value, Alignment, T1, T...>::type type;
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};
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#else
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//***************************************************************************
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// Matcher.
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//***************************************************************************
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template <bool Is_Match, const size_t Alignment, typename T1 = void, typename T2 = void, typename T3 = void, typename T4 = void,
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typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void>
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class type_with_alignment_matcher;
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// Matching alignment.
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template <size_t Alignment, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8>
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class type_with_alignment_matcher <true, Alignment, T1, T2, T3, T4, T5, T6, T7, T8>
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{
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public:
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typedef T1 type;
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};
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// Non-matching alignment.
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template <size_t Alignment, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8>
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class type_with_alignment_matcher <false, Alignment, T1, T2, T3, T4, T5, T6, T7, T8>
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{
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public:
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typedef typename type_with_alignment_matcher<Alignment <= etl::alignment_of<T2>::value, Alignment, T2, T3, T4, T5, T6, T7, T8, void>::type type;
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};
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// Non-matching alignment, none left.
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template <size_t Alignment>
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class type_with_alignment_matcher <false, Alignment, void, void, void, void, void, void, void, void>
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{
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public:
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typedef char type;
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};
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//***************************************************************************
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// Helper.
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//***************************************************************************
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template <size_t Alignment, typename T1, typename T2 = void, typename T3 = void, typename T4 = void,
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typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void>
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class type_with_alignment_helper
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{
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public:
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typedef typename type_with_alignment_matcher<Alignment <= etl::alignment_of<T1>::value, Alignment, T1, T2, T3, T4, T5, T6, T7, T8>::type type;
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};
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#endif
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}
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//***************************************************************************
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/// Gets a type that has the same as the specified alignment.
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///\ingroup alignment
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//***************************************************************************
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template <size_t Alignment>
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class type_with_alignment
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{
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public:
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#if ETL_USING_CPP11
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typedef struct { alignas(Alignment) char dummy; } type;
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#else
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#if ETL_NOT_USING_64BIT_TYPES
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typedef typename private_alignment::type_with_alignment_helper<Alignment, int_least8_t, int_least16_t, int32_t, float, double, void*>::type type;
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#else
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typedef typename private_alignment::type_with_alignment_helper<Alignment, int_least8_t, int_least16_t, int32_t, int64_t, float, double, void*>::type type;
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#endif
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#endif
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ETL_STATIC_ASSERT(etl::alignment_of<type>::value == Alignment, "Unable to create the type with the specified alignment");
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};
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#if ETL_USING_CPP11
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template <size_t Alignment>
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using type_with_alignment_t = typename type_with_alignment<Alignment>::type;
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#endif
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//***************************************************************************
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/// Aligned storage
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/// Length should be determined in terms of sizeof()
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///\ingroup alignment
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//***************************************************************************
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template <size_t Length, const size_t Alignment>
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struct aligned_storage
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{
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struct type
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{
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//type()
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// : data()
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//{
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//}
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/// Convert to T reference.
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template <typename T>
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operator T& ()
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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T* t = *this;
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return *t;
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}
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/// Convert to const T reference.
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template <typename T>
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operator const T& () const
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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const T* t = *this;
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return *t;
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}
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/// Convert to T pointer.
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template <typename T>
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operator T* ()
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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return reinterpret_cast<T*>(data);
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}
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/// Convert to const T pointer.
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template <typename T>
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operator const T* () const
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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return reinterpret_cast<const T*>(data);
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}
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/// Get address as T reference.
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template <typename T>
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T& get_reference()
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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T* t = *this;
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return *t;
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}
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/// Get address as const T reference.
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template <typename T>
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const T& get_reference() const
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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const T* t = *this;
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return *t;
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}
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/// Get address as T pointer.
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template <typename T>
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T* get_address()
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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return reinterpret_cast<T*>(data);
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}
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/// Get address as const T pointer.
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template <typename T>
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const T* get_address() const
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{
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ETL_STATIC_ASSERT((etl::is_same<T*, void*>:: value || ((Alignment % etl::alignment_of<T>::value) == 0)), "Incompatible alignment");
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return reinterpret_cast<const T*>(data);
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}
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#if ETL_USING_CPP11 && !defined(ETL_COMPILER_ARM5)
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alignas(Alignment) char data[Length];
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#else
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union
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{
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char data[Length];
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typename etl::type_with_alignment<Alignment>::type etl_alignment_type; // A POD type that has the same alignment as Alignment.
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};
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#endif
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};
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};
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#if ETL_USING_CPP11
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template <size_t Length, const size_t Alignment>
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using aligned_storage_t = typename aligned_storage<Length, Alignment>::type;
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#endif
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//***************************************************************************
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/// Aligned storage as
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///\ingroup alignment
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//***************************************************************************
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template <size_t Length, typename T>
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struct aligned_storage_as : public etl::aligned_storage<Length, etl::alignment_of<T>::value>
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{
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};
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#if ETL_USING_CPP11
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template <size_t Length, typename T>
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using aligned_storage_as_t = typename aligned_storage_as<Length, T>::type;
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#endif
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}
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#endif
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