310 lines
10 KiB
C++
310 lines
10 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) 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_SMALLEST_INCLUDED
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#define ETL_SMALLEST_INCLUDED
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#include "platform.h"
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#include "integral_limits.h"
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#include <stdint.h>
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///\defgroup smallest smallest
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///\ingroup utilities
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namespace etl
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{
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#if ETL_USING_CPP11 && !defined(ETL_SMALLEST_TYPE_FORCE_CPP03_IMPLEMENTATION)
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//***************************************************************************
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/// Template to determine the largest type and size.
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/// Defines 'value_type' which is the type of the largest parameter.
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/// Defines 'size' which is the size of the largest parameter.
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///\ingroup largest
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//***************************************************************************
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template <typename T1, typename... TRest>
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class smallest_type
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{
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private:
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// Define 'smallest_other' as 'smallest_type' with all but the first
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// parameter.
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using smallest_other = typename smallest_type<TRest...>::type;
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public:
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// Set 'type' to be the smallest of the first parameter and any of the
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// others. This is recursive.
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using type = typename etl::conditional<(etl::size_of<T1>::value < etl::size_of< smallest_other>::value), // Boolean
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T1, // TrueType
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smallest_other> // FalseType
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::type; // The smallest type of the two.
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// The size of the smallest type.
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enum
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{
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size = etl::size_of<type>::value
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};
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};
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//***************************************************************************
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// Specialisation for one template parameter.
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//***************************************************************************
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template <typename T1>
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class smallest_type<T1>
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{
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public:
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using type = T1;
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enum
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{
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size = etl::size_of<type>::value
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};
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};
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#if ETL_USING_CPP11
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template <typename... T>
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using smallest_type_t = typename smallest_type<T...>::type;
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#endif
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#if ETL_USING_CPP17
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template <typename... T>
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constexpr size_t smallest_type_v = smallest_type<T...>::size;
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#endif
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#else
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#include "private/smallest_cpp03.h"
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#endif
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namespace private_smallest
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{
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//*************************************************************************
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// Determine the type to hold the number of bits based on the index.
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//*************************************************************************
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template <int index>
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struct best_fit_uint_type;
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//*************************************************************************
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// Less than or equal to 8 bits.
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//*************************************************************************
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template <>
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struct best_fit_uint_type<0>
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{
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typedef uint_least8_t type;
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};
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//*************************************************************************
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// 9 to 16 bits.
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//*************************************************************************
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template <>
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struct best_fit_uint_type<1>
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{
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typedef uint_least16_t type;
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};
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//*************************************************************************
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// 17 to 31 bits.
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//*************************************************************************
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template <>
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struct best_fit_uint_type<2>
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{
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typedef uint_least32_t type;
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};
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#if ETL_USING_64BIT_TYPES
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//*************************************************************************
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// Greater than 32 bits.
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//*************************************************************************
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template <>
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struct best_fit_uint_type<3>
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{
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typedef uint_least64_t type;
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};
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#endif
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//*************************************************************************
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// Determine the type to hold the number of bits based on the index.
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//*************************************************************************
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template <int index>
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struct best_fit_int_type;
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//*************************************************************************
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// Less than or equal to 8 bits.
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//*************************************************************************
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template <>
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struct best_fit_int_type<0>
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{
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typedef int_least8_t type;
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};
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//*************************************************************************
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// 9 to 16 bits.
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//*************************************************************************
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template <>
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struct best_fit_int_type<1>
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{
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typedef int_least16_t type;
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};
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//*************************************************************************
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// 17 to 31 bits.
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//*************************************************************************
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template <>
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struct best_fit_int_type<2>
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{
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typedef int_least32_t type;
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};
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#if ETL_USING_64BIT_TYPES
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//*************************************************************************
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// Greater than 32 bits.
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//*************************************************************************
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template <>
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struct best_fit_int_type<3>
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{
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typedef int_least64_t type;
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};
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#endif
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} // namespace private_smallest
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//***************************************************************************
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/// Template to determine the smallest unsigned int type that can contain a
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/// value with the specified number of bits.
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/// Defines 'type' which is the type of the smallest unsigned integer.
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///\ingroup smallest
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//***************************************************************************
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template <size_t NBITS>
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struct smallest_uint_for_bits
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{
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private:
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// Determines the index of the best unsigned type for the required number of
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// bits.
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static ETL_CONSTANT int TYPE_INDEX = ((NBITS > 8) ? 1 : 0) + ((NBITS > 16) ? 1 : 0) + ((NBITS > 32) ? 1 : 0);
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public:
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typedef typename private_smallest::best_fit_uint_type<TYPE_INDEX>::type type;
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};
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template <size_t NBITS>
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ETL_CONSTANT int smallest_uint_for_bits<NBITS>::TYPE_INDEX;
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#if ETL_USING_CPP11
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template <size_t NBITS>
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using smallest_uint_for_bits_t = typename smallest_uint_for_bits<NBITS>::type;
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#endif
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//***************************************************************************
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/// Template to determine the smallest signed int type that can contain a
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/// value with the specified number of bits.
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/// Defines 'type' which is the type of the smallest signed integer.
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///\ingroup smallest
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//***************************************************************************
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template <size_t NBITS>
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struct smallest_int_for_bits
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{
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private:
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// Determines the index of the best unsigned type for the required number of
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// bits.
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static ETL_CONSTANT int TYPE_INDEX = ((NBITS > 8) ? 1 : 0) + ((NBITS > 16) ? 1 : 0) + ((NBITS > 32) ? 1 : 0);
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public:
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typedef typename private_smallest::best_fit_int_type<TYPE_INDEX>::type type;
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};
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template <size_t NBITS>
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ETL_CONSTANT int smallest_int_for_bits<NBITS>::TYPE_INDEX;
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#if ETL_USING_CPP11
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template <size_t NBITS>
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using smallest_int_for_bits_t = typename smallest_int_for_bits<NBITS>::type;
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#endif
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//***************************************************************************
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/// Template to determine the smallest unsigned int type that can contain the
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/// specified unsigned value.
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/// Defines 'type' which is the type of the smallest unsigned integer.
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///\ingroup smallest
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//***************************************************************************
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template <uintmax_t VALUE>
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struct smallest_uint_for_value
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{
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private:
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// Determines the index of the best unsigned type for the required value.
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static ETL_CONSTANT int TYPE_INDEX = ((VALUE > UINT_LEAST8_MAX) ? 1 : 0) + ((VALUE > UINT16_MAX) ? 1 : 0) + ((VALUE > UINT32_MAX) ? 1 : 0);
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public:
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typedef typename private_smallest::best_fit_uint_type<TYPE_INDEX>::type type;
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};
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template <uintmax_t VALUE>
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ETL_CONSTANT int smallest_uint_for_value<VALUE>::TYPE_INDEX;
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#if ETL_USING_CPP11
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template <uintmax_t VALUE>
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using smallest_uint_for_value_t = typename smallest_uint_for_value<VALUE>::type;
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#endif
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//***************************************************************************
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/// Template to determine the smallest int type that can contain the
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/// specified signed value.
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/// Defines 'type' which is the type of the smallest signed integer.
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///\ingroup smallest
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//***************************************************************************
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template <intmax_t VALUE>
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struct smallest_int_for_value
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{
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private:
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// Determines the index of the best signed type for the required value.
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static ETL_CONSTANT int TYPE_INDEX = (((VALUE > intmax_t(INT_LEAST8_MAX)) || (VALUE < intmax_t(INT_LEAST8_MIN))) ? 1 : 0)
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+ (((VALUE > intmax_t(INT16_MAX)) || (VALUE < intmax_t(INT16_MIN))) ? 1 : 0)
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+ (((VALUE > intmax_t(INT32_MAX)) || (VALUE < intmax_t(INT32_MIN))) ? 1 : 0);
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public:
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typedef typename private_smallest::best_fit_int_type<TYPE_INDEX>::type type;
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};
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template <intmax_t VALUE>
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ETL_CONSTANT int smallest_int_for_value<VALUE>::TYPE_INDEX;
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#if ETL_USING_CPP11
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template <intmax_t VALUE>
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using smallest_int_for_value_t = typename smallest_int_for_value<VALUE>::type;
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#endif
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} // namespace etl
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#endif
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