bslmf_isintegral.h

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/// @file bslmf_isintegral.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bslmf_isintegral.h                                                 -*-C++-*-
#ifndef INCLUDED_BSLMF_ISINTEGRAL
#define INCLUDED_BSLMF_ISINTEGRAL
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bslmf_isintegral bslmf_isintegral
/// @brief  Provide a compile-time check for integral types.
/// @addtogroup bsl
/// @{
/// @addtogroup bslmf
/// @{
/// @addtogroup bslmf_isintegral
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bslmf_isintegral-purpose"> Purpose</a>
/// * <a href="#bslmf_isintegral-classes"> Classes </a>
/// * <a href="#bslmf_isintegral-description"> Description </a>
///   * <a href="#bslmf_isintegral-usage"> Usage </a>
///     * <a href="#bslmf_isintegral-example-1-verify-integral-types"> Example 1: Verify Integral Types </a>
///
/// # Purpose {#bslmf_isintegral-purpose}
/// Provide a compile-time check for integral types.
///
/// # Classes {#bslmf_isintegral-classes}
///
/// -  bsl::is_integral: standard meta-function for determining integral types
/// -  bsl::is_integral_v: the result value of `bsl::is_integral`
///
/// @see  bslmf_integralconstant
///
/// # Description {#bslmf_isintegral-description}
/// This component defines a meta-function, `bsl::is_integral` and
/// a template variable `bsl::is_integral_v`, that represents the result value
/// of the `bsl::is_integral` meta-function, that may be used to query whether a
/// type is an integral type as defined in section 3.9.1.7 of the C++11 standard
/// [basic.fundamental] (excluding those types that were introduced in C++11).
///
/// `bsl::is_integral` meets the requirements of the `is_integral` template
/// defined in the C++11 standard [meta.unary.cat] except that it may not
/// correctly evaluate types introduced in C++11.
///
/// Note that the template variable `is_integral_v` is defined in the C++17
/// standard as an inline variable.  If the current compiler supports the inline
/// variable C++17 compiler feature, `bsl::is_integral_v` is defined as an
/// `inline constexpr bool` variable.  Otherwise, if the compiler supports the
/// variable templates C++14 compiler feature, `bsl::is_integral_v` is defined
/// as a non-inline `constexpr bool` variable.  See
/// `BSLS_COMPILERFEATURES_SUPPORT_INLINE_VARIABLES` and
/// `BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES` macros in
/// bsls_compilerfeatures component for details.
///
/// ## Usage {#bslmf_isintegral-usage}
///
///
/// In this section we show intended use of this component.
///
/// ### Example 1: Verify Integral Types {#bslmf_isintegral-example-1-verify-integral-types}
///
///
/// Suppose that we want to assert whether a particular type is an integral
/// type.
///
/// First, we create two `typedef`s -- an integral type and a non-integral type:
/// @code
/// typedef void MyType;
/// typedef int  MyIntegralType;
/// @endcode
/// Now, we instantiate the `bsl::is_integral` template for each of the
/// `typedef`s and assert the `value` static data member of each instantiation:
/// @code
/// assert(false == bsl::is_integral<MyType>::value);
/// assert(true  == bsl::is_integral<MyIntegralType>::value);
/// @endcode
/// Note that if the current compiler supports the variable templates C++14
/// feature then we can re-write the snippet of code above using the
/// `bsl::is_integral_v` variable as follows:
/// @code
/// #ifdef BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES
///   assert(false == bsl::is_integral_v<MyType>);
///   assert(true  == bsl::is_integral_v<MyIntegralType>);
/// #endif
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bsl
 * @{
 */
/** @addtogroup bslmf
 * @{
 */
/** @addtogroup bslmf_isintegral
 * @{
 */
 
#include <bslscm_version.h>
 
#include <bslmf_integralconstant.h>
 
#include <bsls_compilerfeatures.h>
#include <bsls_keyword.h>
#include <bsls_libraryfeatures.h>
 
#ifndef BDE_DONT_ALLOW_TRANSITIVE_INCLUDES
#include <bslmf_removecv.h>
#endif // BDE_DONT_ALLOW_TRANSITIVE_INCLUDES
 
#ifdef BSLS_LIBRARYFEATURES_HAS_CPP11_BASELINE_LIBRARY
#include <type_traits> // 'std::is_integral', 'std::is_integral_v'
#endif
namespace bsl {
                         // ==================
                         // struct is_integral
                         // ==================
 
#ifdef BSLS_LIBRARYFEATURES_HAS_CPP11_BASELINE_LIBRARY
template <class t_TYPE>
struct is_integral : bsl::integral_constant<bool,
                                            std::is_integral<t_TYPE>::value>
{};
 
#else
 
/// This `struct` template implements the `is_integral` meta-function
/// defined in the C++11 standard [meta.unary.cat] to determine if the
/// (template parameter) `t_TYPE` is an integral type.  This `struct`
/// derives from `bsl::true_type` if the `t_TYPE` is an integral type, and
/// `bsl::false_type` otherwise.
template <class t_TYPE>
struct is_integral : bsl::false_type {
};
 
/// This partial specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `const`-qualified delegates to the
/// non-cv-qualified primary template.
template <class t_TYPE>
struct is_integral<const t_TYPE> : is_integral<t_TYPE>::type {
};
 
/// This partial specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `volatile`-qualified delegates to the
/// non-cv-qualified primary template.
template <class t_TYPE>
struct is_integral<volatile t_TYPE> : is_integral<t_TYPE>::type {
};
 
/// This partial specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `const volatile`-qualified delegates to the
/// non-cv-qualified primary template.
template <class t_TYPE>
struct is_integral<const volatile t_TYPE> : is_integral<t_TYPE>::type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `bool`, derives from `bsl::true_type`.
template <>
struct is_integral<bool> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `char`, derives from `bsl::true_type`.
template <>
struct is_integral<char> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `wchar_t`, derives from `bsl::true_type`.
template <>
struct is_integral<wchar_t> : bsl::true_type {
};
 
#if defined(BSLS_COMPILERFEATURES_SUPPORT_UTF8_CHAR_TYPE)
template <>
struct is_integral<char8_t> : bsl::true_type {
     // This explicit specialization of 'is_integral', for when the (template
     // parameter) 'TYPE' is 'wchar_t', derives from 'bsl::true_type'.
};
#endif  // BSLS_COMPILERFEATURES_SUPPORT_UTF8_CHAR_TYPE
 
#if defined BSLS_COMPILERFEATURES_SUPPORT_UNICODE_CHAR_TYPES
template <>
struct is_integral<char16_t> : bsl::true_type {
    // This explicit specialization of 'is_integral', for when the (template
    // parameter) 't_TYPE' is 'wchar_t', derives from 'bsl::true_type'.
};
 
template <>
struct is_integral<char32_t> : bsl::true_type {
    // This explicit specialization of 'is_integral', for when the (template
    // parameter) 't_TYPE' is 'wchar_t', derives from 'bsl::true_type'.
};
#endif // BSLS_COMPILERFEATURES_SUPPORT_UNICODE_CHAR_TYPES
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `signed char`, derives from `bsl::true_type`.
template <>
struct is_integral<signed char> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `unsigned char`, derives from `bsl::true_type`.
template <>
struct is_integral<unsigned char> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `short`, derives from `bsl::true_type`.
template <>
struct is_integral<short int> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `unsigned short`, derives from `bsl::true_type`.
template <>
struct is_integral<unsigned short int> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `int`, derives from `bsl::true_type`.
template <>
struct is_integral<int> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `unsigned int`, derives from `bsl::true_type`.
template <>
struct is_integral<unsigned int> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `long int`, derives from `bsl::true_type`.
template <>
struct is_integral<long int> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `unsigned long int`, derives from
/// `bsl::true_type`.
template <>
struct is_integral<unsigned long int> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `long long int`, derives from `bsl::true_type`.
template <>
struct is_integral<long long int> : bsl::true_type {
};
 
/// This explicit specialization of `is_integral`, for when the (template
/// parameter) `t_TYPE` is `unsigned long long int`, derives from
/// `bsl::true_type`.
template <>
struct is_integral<unsigned long long int> : bsl::true_type {
};
#endif // BSLS_LIBRARYFEATURES_HAS_CPP11_BASELINE_LIBRARY
 
#ifdef BSLS_LIBRARYFEATURES_HAS_CPP17_BASELINE_LIBRARY
using std::is_integral_v;
#else
#ifdef BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES
template <class t_TYPE>
BSLS_KEYWORD_INLINE_VARIABLE constexpr bool is_integral_v =
                                            is_integral<t_TYPE>::value;
    // This template variable represents the result value of the
    // 'bsl::is_integral' meta-function.
#endif
#endif // BSLS_LIBRARYFEATURES_HAS_CPP17_BASELINE_LIBRARY
 
}  // close namespace bsl
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2013 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */