mirror of
https://github.com/matrix-construct/construct
synced 2024-12-27 07:54:05 +01:00
994 lines
23 KiB
C++
994 lines
23 KiB
C++
/*
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* charybdis: 21st Century IRC++d
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* util.h: Miscellaneous utilities
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*
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* Copyright (C) 2016 Charybdis Development Team
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* Copyright (C) 2016 Jason Volk <jason@zemos.net>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice is present in all copies.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#pragma once
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#define HAVE_IRCD_UTIL_H
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/// Tools for developers
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namespace ircd::util
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{
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}
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namespace ircd {
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inline namespace util {
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#define IRCD_EXPCAT(a, b) a ## b
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#define IRCD_CONCAT(a, b) IRCD_EXPCAT(a, b)
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#define IRCD_UNIQUE(a) IRCD_CONCAT(a, __COUNTER__)
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#define IRCD_OVERLOAD(NAME) \
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static constexpr struct NAME##_t {} NAME {};
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#define IRCD_USING_OVERLOAD(ALIAS, ORIGIN) \
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static constexpr const auto &ALIAS{ORIGIN}
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#define IRCD_WEAK_TYPEDEF(TYPE, NAME) \
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struct NAME \
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:TYPE \
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{ \
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using TYPE::TYPE; \
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};
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#define IRCD_STRONG_TYPEDEF(TYPE, NAME) \
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struct NAME \
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{ \
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TYPE val; \
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\
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explicit operator const TYPE &() const { return val; } \
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explicit operator TYPE &() { return val; } \
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};
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#define IRCD_WEAK_T(TYPE) \
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IRCD_WEAK_TYPEDEF(TYPE, IRCD_UNIQUE(weak_t))
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// ex: using foo_t = IRCD_STRONG_T(int)
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#define IRCD_STRONG_T(TYPE) \
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IRCD_STRONG_TYPEDEF(TYPE, IRCD_UNIQUE(strong_t))
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/* Output the sizeof a structure at compile time.
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* This stops the compiler with an error (good) containing the size of the target
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* in the message.
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*
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* example: struct foo {}; IRCD_TEST_SIZEOF(foo)
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*/
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template<size_t SIZE>
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struct _TEST_SIZEOF_;
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#define IRCD_TEST_SIZEOF(name) \
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ircd::util::_TEST_SIZEOF_<sizeof(name)> _test_;
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// for complex static initialization (try to avoid this though)
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enum class init_priority
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{
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FIRST = 101,
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STD_CONTAINER = 102,
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};
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#define IRCD_INIT_PRIORITY(name) \
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__attribute__((init_priority(int(ircd::init_priority::name))))
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///
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/// C++14 user defined literals
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///
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/// These are very useful for dealing with space. Simply write 8_MiB and it's
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/// as if a macro turned that into (8 * 1024 * 1024) at compile time.
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///
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/// (Internal) Defines a unit literal with an unsigned long long basis.
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///
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#define IRCD_UNIT_LITERAL_UL(name, morphism) \
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constexpr auto \
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operator"" _ ## name(const unsigned long long val) \
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{ \
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return (morphism); \
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}
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/// (Internal) Defines a unit literal with a signed long long basis
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///
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#define IRCD_UNIT_LITERAL_LL(name, morphism) \
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constexpr auto \
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operator"" _ ## name(const long long val) \
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{ \
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return (morphism); \
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}
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/// (Internal) Defines a unit literal with a long double basis
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///
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#define IRCD_UNIT_LITERAL_LD(name, morphism) \
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constexpr auto \
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operator"" _ ## name(const long double val) \
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{ \
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return (morphism); \
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}
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// IEC unit literals
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IRCD_UNIT_LITERAL_UL( B, val )
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IRCD_UNIT_LITERAL_UL( KiB, val * 1024LL )
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IRCD_UNIT_LITERAL_UL( MiB, val * 1024LL * 1024LL )
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IRCD_UNIT_LITERAL_UL( GiB, val * 1024LL * 1024LL * 1024LL )
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IRCD_UNIT_LITERAL_UL( TiB, val * 1024LL * 1024LL * 1024LL * 1024LL )
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IRCD_UNIT_LITERAL_UL( PiB, val * 1024LL * 1024LL * 1024LL * 1024LL * 1024LL )
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IRCD_UNIT_LITERAL_UL( EiB, val * 1024LL * 1024LL * 1024LL * 1024LL * 1024LL * 1024LL )
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IRCD_UNIT_LITERAL_LD( B, val )
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IRCD_UNIT_LITERAL_LD( KiB, val * 1024.0L )
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IRCD_UNIT_LITERAL_LD( MiB, val * 1024.0L * 1024.0L )
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IRCD_UNIT_LITERAL_LD( GiB, val * 1024.0L * 1024.0L * 1024.0L )
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IRCD_UNIT_LITERAL_LD( TiB, val * 1024.0L * 1024.0L * 1024.0L * 1024.0L )
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IRCD_UNIT_LITERAL_LD( PiB, val * 1024.0L * 1024.0L * 1024.0L * 1024.0L * 1024.0L )
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IRCD_UNIT_LITERAL_LD( EiB, val * 1024.0L * 1024.0L * 1024.0L * 1024.0L * 1024.0L * 1024.0L )
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// SI unit literals
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IRCD_UNIT_LITERAL_UL( KB, val * 1000LL )
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IRCD_UNIT_LITERAL_UL( MB, val * 1000LL * 1000LL )
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IRCD_UNIT_LITERAL_UL( GB, val * 1000LL * 1000LL * 1000LL )
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IRCD_UNIT_LITERAL_UL( TB, val * 1000LL * 1000LL * 1000LL * 1000LL )
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IRCD_UNIT_LITERAL_UL( PB, val * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL )
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IRCD_UNIT_LITERAL_UL( EB, val * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL )
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IRCD_UNIT_LITERAL_LD( KB, val * 1000.0L )
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IRCD_UNIT_LITERAL_LD( MB, val * 1000.0L * 1000.0L )
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IRCD_UNIT_LITERAL_LD( GB, val * 1000.0L * 1000.0L * 1000.0L )
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IRCD_UNIT_LITERAL_LD( TB, val * 1000.0L * 1000.0L * 1000.0L * 1000.0L )
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IRCD_UNIT_LITERAL_LD( PB, val * 1000.0L * 1000.0L * 1000.0L * 1000.0L * 1000.0L )
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IRCD_UNIT_LITERAL_LD( EB, val * 1000.0L * 1000.0L * 1000.0L * 1000.0L * 1000.0L * 1000.0L )
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///
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/// Fundamental scope-unwind utilities establishing actions during destruction
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///
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/// Unconditionally executes the provided code when the object goes out of scope.
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///
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struct unwind
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{
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struct nominal;
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struct exceptional;
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const std::function<void ()> func;
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template<class F>
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unwind(F &&func)
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:func{std::forward<F>(func)}
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{}
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unwind(const unwind &) = delete;
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unwind &operator=(const unwind &) = delete;
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~unwind() noexcept
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{
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func();
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}
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};
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/// Executes function only if the unwind takes place without active exception
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///
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/// The function is expected to be executed and the likely() should pipeline
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/// that branch and make this device cheaper to use under normal circumstances.
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///
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struct unwind::nominal
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{
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const std::function<void ()> func;
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template<class F>
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nominal(F &&func)
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:func{std::forward<F>(func)}
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{}
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~nominal() noexcept
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{
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if(likely(!std::uncaught_exception()))
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func();
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}
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nominal(const nominal &) = delete;
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};
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/// Executes function only if unwind is taking place because exception thrown
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///
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/// The unlikely() intends for the cost of a branch misprediction to be paid
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/// for fetching and executing this function. This is because we strive to
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/// optimize the pipeline for the nominal path, making this device as cheap
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/// as possible to use.
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///
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struct unwind::exceptional
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{
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const std::function<void ()> func;
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template<class F>
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exceptional(F &&func)
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:func{std::forward<F>(func)}
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{}
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~exceptional() noexcept
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{
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if(unlikely(std::uncaught_exception()))
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func();
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}
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exceptional(const exceptional &) = delete;
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};
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template<class T>
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using custom_ptr = std::unique_ptr<T, std::function<void (T *) noexcept>>;
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// For conforming enums include a _NUM_ as the last element,
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// then num_of<my_enum>() works
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template<class Enum>
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constexpr
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typename std::underlying_type<Enum>::type
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num_of()
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{
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return static_cast<typename std::underlying_type<Enum>::type>(Enum::_NUM_);
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}
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// Iteration of a num_of() conforming enum
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template<class Enum>
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typename std::enable_if<std::is_enum<Enum>::value, void>::type
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for_each(const std::function<void (const Enum &)> &func)
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{
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for(size_t i(0); i < num_of<Enum>(); ++i)
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func(static_cast<Enum>(i));
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}
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/**
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* flag-enum utilities
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*
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* This relaxes the strong typing of enums to allow bitflags with operations on the elements
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* with intuitive behavior.
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*
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* If the project desires absolute guarantees on the strong enum typing then this can be tucked
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* away in some namespace and imported into select scopes instead.
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*/
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
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operator~(const Enum &a)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return static_cast<Enum>(~static_cast<enum_t>(a));
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}
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, bool>::type
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operator!(const Enum &a)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return !static_cast<enum_t>(a);
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}
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
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operator|(const Enum &a, const Enum &b)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return static_cast<Enum>(static_cast<enum_t>(a) | static_cast<enum_t>(b));
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}
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
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operator&(const Enum &a, const Enum &b)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return static_cast<Enum>(static_cast<enum_t>(a) & static_cast<enum_t>(b));
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}
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
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operator^(const Enum &a, const Enum &b)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return static_cast<Enum>(static_cast<enum_t>(a) ^ static_cast<enum_t>(b));
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}
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, Enum &>::type
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operator|=(Enum &a, const Enum &b)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return (a = (a | b));
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}
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, Enum &>::type
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operator&=(Enum &a, const Enum &b)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return (a = (a & b));
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}
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template<class Enum>
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constexpr
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typename std::enable_if<std::is_enum<Enum>::value, Enum &>::type
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operator^=(Enum &a, const Enum &b)
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{
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using enum_t = typename std::underlying_type<Enum>::type;
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return (a = (a ^ b));
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}
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template<class Enum,
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class it>
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typename std::enable_if<std::is_enum<Enum>::value, typename std::underlying_type<Enum>::type>::type
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combine_flags(const it &begin,
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const it &end)
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{
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using type = typename std::underlying_type<Enum>::type;
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return std::accumulate(begin, end, type(0), []
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(auto ret, const auto &val)
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{
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return ret |= type(val);
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});
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}
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template<class Enum>
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typename std::enable_if<std::is_enum<Enum>::value, typename std::underlying_type<Enum>::type>::type
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combine_flags(const std::initializer_list<Enum> &list)
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{
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return combine_flags<Enum>(begin(list), end(list));
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}
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inline size_t
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size(std::ostream &s)
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{
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const auto cur(s.tellp());
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s.seekp(0, std::ios::end);
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const auto ret(s.tellp());
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s.seekp(cur, std::ios::beg);
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return ret;
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}
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template<class T>
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auto
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string(const T &s)
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{
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std::stringstream ss;
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return static_cast<std::stringstream &>(ss << s).str();
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}
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inline auto
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string(const char *const &buf, const size_t &size)
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{
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return std::string{buf, size};
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}
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inline auto
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string(const uint8_t *const &buf, const size_t &size)
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{
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return string(reinterpret_cast<const char *>(buf), size);
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}
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//
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// stringstream buffer set macros
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//
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inline std::string &
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pubsetbuf(std::stringstream &ss,
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std::string &s)
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{
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auto *const &data
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{
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const_cast<char *>(s.data())
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};
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ss.rdbuf()->pubsetbuf(data, s.size());
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return s;
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}
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inline std::string &
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pubsetbuf(std::stringstream &ss,
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std::string &s,
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const size_t &size)
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{
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s.resize(size, char{});
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return pubsetbuf(ss, s);
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}
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inline std::string &
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resizebuf(std::stringstream &ss,
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std::string &s)
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{
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s.resize(ss.tellp());
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return s;
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}
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/* This is a template alternative to nothrow overloads, which
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* allows keeping the function arguments sanitized of the thrownness.
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*/
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template<class exception_t>
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constexpr bool
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is_nothrow()
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{
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return std::is_same<exception_t, std::nothrow_t>::value;
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}
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template<class exception_t = std::nothrow_t,
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class return_t = bool>
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using nothrow_overload = typename std::enable_if<is_nothrow<exception_t>(), return_t>::type;
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template<class exception_t,
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class return_t = void>
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using throw_overload = typename std::enable_if<!is_nothrow<exception_t>(), return_t>::type;
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//
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// Test if type is forward declared or complete
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//
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template<class T,
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class = void>
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struct is_complete
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:std::false_type
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{
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};
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template<class T>
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struct is_complete<T, decltype(void(sizeof(T)))>
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:std::true_type
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{
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};
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//
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// Convenience constexprs for iterators
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//
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template<class It>
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constexpr auto
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is_iterator()
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{
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return std::is_base_of<typename std::iterator_traits<It>::value_type, It>::value;
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}
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template<class It>
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constexpr auto
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is_forward_iterator()
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{
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return std::is_base_of<std::forward_iterator_tag, typename std::iterator_traits<It>::iterator_category>::value;
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}
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template<class It>
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constexpr auto
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is_input_iterator()
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{
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return std::is_base_of<std::forward_iterator_tag, typename std::iterator_traits<It>::iterator_category>::value;
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}
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// std::next with out_of_range exception
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template<class It>
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typename std::enable_if<is_forward_iterator<It>() || is_input_iterator<It>(), It>::type
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at(It &&start,
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It &&stop,
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ssize_t i)
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{
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for(; start != stop; --i, std::advance(start, 1))
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if(!i)
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return start;
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throw std::out_of_range("at(a, b, i): 'i' out of range");
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}
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//
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// Some functors for STL
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//
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template<class container>
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struct keys
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{
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auto &operator()(typename container::reference v) const
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{
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return v.first;
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}
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};
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template<class container>
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struct values
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{
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auto &operator()(typename container::reference v) const
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{
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return v.second;
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}
|
|
};
|
|
|
|
|
|
//
|
|
// Error-checking closure for POSIX system calls. Note the usage is
|
|
// syscall(read, foo, bar, baz) not a macro like syscall(read(foo, bar, baz));
|
|
//
|
|
template<int ERROR_CODE = -1,
|
|
class function,
|
|
class... args>
|
|
auto
|
|
syscall(function&& f,
|
|
args&&... a)
|
|
-> typename std::enable_if<std::is_same<int, decltype(f(a...))>::value, int>::type
|
|
{
|
|
const int ret
|
|
{
|
|
f(std::forward<args>(a)...)
|
|
};
|
|
|
|
if(unlikely(ret == ERROR_CODE))
|
|
throw std::system_error(errno, std::system_category());
|
|
|
|
return ret;
|
|
}
|
|
|
|
//
|
|
// Error-checking closure for POSIX system calls. Note the usage is
|
|
// syscall(read, foo, bar, baz) not a macro like syscall(read(foo, bar, baz));
|
|
//
|
|
template<int ERROR_CODE = -1,
|
|
class function,
|
|
class... args>
|
|
auto
|
|
uninterruptible_syscall(function&& f,
|
|
args&&... a)
|
|
-> typename std::enable_if<std::is_same<int, decltype(f(a...))>::value, int>::type
|
|
{
|
|
int ret; do
|
|
{
|
|
ret = f(std::forward<args>(a)...);
|
|
}
|
|
while(unlikely(ret == ERROR_CODE && errno == EINTR));
|
|
|
|
if(unlikely(ret == ERROR_CODE))
|
|
throw std::system_error(errno, std::system_category());
|
|
|
|
return ret;
|
|
}
|
|
|
|
|
|
//
|
|
// Similar to a va_list, but conveying std-c++ type data acquired from a variadic template
|
|
// parameter pack acting as the ...) elipsis. This is used to implement fmt::snprintf(),
|
|
// exceptions and logger et al in their respective translation units rather than the header
|
|
// files.
|
|
//
|
|
// Limitations: The choice of a fixed array of N is because std::initializer_list doesn't
|
|
// work here and other containers may be heavy in this context. Ideas to improve this are
|
|
// welcome.
|
|
//
|
|
const size_t VA_RTTI_MAX_SIZE = 12;
|
|
struct va_rtti
|
|
:std::array<std::pair<const void *, const std::type_info *>, VA_RTTI_MAX_SIZE>
|
|
{
|
|
using base_type = std::array<value_type, VA_RTTI_MAX_SIZE>;
|
|
|
|
static constexpr size_t max_size()
|
|
{
|
|
return std::tuple_size<base_type>();
|
|
}
|
|
|
|
size_t argc;
|
|
const size_t &size() const
|
|
{
|
|
return argc;
|
|
}
|
|
|
|
template<class... Args>
|
|
va_rtti(Args&&... args)
|
|
:base_type
|
|
{{
|
|
std::make_pair(std::addressof(args), std::addressof(typeid(Args)))...
|
|
}}
|
|
,argc
|
|
{
|
|
sizeof...(args)
|
|
}
|
|
{
|
|
assert(argc <= max_size());
|
|
}
|
|
};
|
|
|
|
static_assert
|
|
(
|
|
sizeof(va_rtti) == (va_rtti::max_size() * 16) + 8,
|
|
"va_rtti should be (8 + 8) * N + 8;"
|
|
" where 8 + 8 are the two pointers carrying the argument and its type data;"
|
|
" where N is the max arguments;"
|
|
" where the final + 8 bytes holds the actual number of arguments passed;"
|
|
);
|
|
|
|
|
|
//
|
|
// To collapse pairs of iterators down to a single type
|
|
//
|
|
|
|
template<class T>
|
|
struct iterpair
|
|
:std::pair<T, T>
|
|
{
|
|
using std::pair<T, T>::pair;
|
|
};
|
|
|
|
template<class T>
|
|
T &
|
|
begin(iterpair<T> &i)
|
|
{
|
|
return std::get<0>(i);
|
|
}
|
|
|
|
template<class T>
|
|
T &
|
|
end(iterpair<T> &i)
|
|
{
|
|
return std::get<1>(i);
|
|
}
|
|
|
|
template<class T>
|
|
const T &
|
|
begin(const iterpair<T> &i)
|
|
{
|
|
return std::get<0>(i);
|
|
}
|
|
|
|
template<class T>
|
|
const T &
|
|
end(const iterpair<T> &i)
|
|
{
|
|
return std::get<1>(i);
|
|
}
|
|
|
|
//
|
|
// To collapse pairs of iterators down to a single type
|
|
// typed by an object with iterator typedefs.
|
|
//
|
|
|
|
template<class T>
|
|
using iterators = std::pair<typename T::iterator, typename T::iterator>;
|
|
|
|
template<class T>
|
|
using const_iterators = std::pair<typename T::const_iterator, typename T::const_iterator>;
|
|
|
|
template<class T>
|
|
typename T::iterator
|
|
begin(const iterators<T> &i)
|
|
{
|
|
return i.first;
|
|
}
|
|
|
|
template<class T>
|
|
typename T::iterator
|
|
end(const iterators<T> &i)
|
|
{
|
|
return i.second;
|
|
}
|
|
|
|
template<class T>
|
|
typename T::const_iterator
|
|
begin(const const_iterators<T> &ci)
|
|
{
|
|
return ci.first;
|
|
}
|
|
|
|
template<class T>
|
|
typename T::const_iterator
|
|
end(const const_iterators<T> &ci)
|
|
{
|
|
return ci.second;
|
|
}
|
|
|
|
|
|
//
|
|
// For objects using the pattern of adding their own instance to a container
|
|
// in their constructor, storing an iterator as a member, and then removing
|
|
// themselves using the iterator in their destructor. It is unsafe to do that.
|
|
// Use this instead; or better, use ircd::instance_list<>
|
|
//
|
|
template<class container,
|
|
class iterator = typename container::iterator>
|
|
struct unique_iterator
|
|
{
|
|
container *c;
|
|
iterator it;
|
|
|
|
unique_iterator(container &c, iterator it)
|
|
:c{&c}
|
|
,it{std::move(it)}
|
|
{}
|
|
|
|
unique_iterator()
|
|
:c{nullptr}
|
|
{}
|
|
|
|
unique_iterator(const unique_iterator &) = delete;
|
|
unique_iterator(unique_iterator &&o) noexcept
|
|
:c{std::move(o.c)}
|
|
,it{std::move(o.it)}
|
|
{
|
|
o.c = nullptr;
|
|
}
|
|
|
|
unique_iterator &operator=(const unique_iterator &) = delete;
|
|
unique_iterator &operator=(unique_iterator &&o) noexcept
|
|
{
|
|
this->~unique_iterator();
|
|
c = std::move(o.c);
|
|
it = std::move(o.it);
|
|
o.c = nullptr;
|
|
return *this;
|
|
}
|
|
|
|
~unique_iterator() noexcept
|
|
{
|
|
if(c)
|
|
c->erase(it);
|
|
}
|
|
};
|
|
|
|
template<class container>
|
|
struct unique_const_iterator
|
|
:unique_iterator<container, typename container::const_iterator>
|
|
{
|
|
using iterator_type = typename container::const_iterator;
|
|
using unique_iterator<container, iterator_type>::unique_iterator;
|
|
};
|
|
|
|
|
|
/// The instance_list pattern is where every instance of a class registers
|
|
/// itself in a static list of all instances and removes itself on dtor.
|
|
/// IRCd Ex. All clients use instance_list so all clients can be listed for
|
|
/// an administrator or be interrupted and disconnected on server shutdown.
|
|
///
|
|
/// `struct myobj : ircd::instance_list<myobj> {};`
|
|
///
|
|
/// * The creator of the class no longer has to manually specify what is
|
|
/// defined here using unique_iterator; however, one still must provide
|
|
/// linkage for the static list.
|
|
///
|
|
/// * The container pointer used by unique_iterator is eliminated here
|
|
/// because of the static list.
|
|
///
|
|
template<class T>
|
|
struct instance_list
|
|
{
|
|
static std::list<T *> list;
|
|
|
|
protected:
|
|
typename decltype(list)::iterator it;
|
|
|
|
instance_list(typename decltype(list)::iterator it)
|
|
:it{std::move(it)}
|
|
{}
|
|
|
|
instance_list()
|
|
:it{list.emplace(end(list), static_cast<T *>(this))}
|
|
{}
|
|
|
|
instance_list(const instance_list &) = delete;
|
|
instance_list(instance_list &&o) noexcept
|
|
:it{std::move(o.it)}
|
|
{
|
|
o.it = end(list);
|
|
}
|
|
|
|
instance_list &operator=(const instance_list &) = delete;
|
|
instance_list &operator=(instance_list &&o) noexcept
|
|
{
|
|
std::swap(it, o.it);
|
|
return *this;
|
|
}
|
|
|
|
~instance_list() noexcept
|
|
{
|
|
if(it != end(list))
|
|
list.erase(it);
|
|
}
|
|
};
|
|
|
|
|
|
//
|
|
// Compile-time comparison of string literals
|
|
//
|
|
constexpr bool
|
|
_constexpr_equal(const char *a,
|
|
const char *b)
|
|
{
|
|
return *a == *b && (*a == '\0' || _constexpr_equal(a + 1, b + 1));
|
|
}
|
|
|
|
|
|
inline auto
|
|
operator!(const std::string &str)
|
|
{
|
|
return str.empty();
|
|
}
|
|
|
|
inline auto
|
|
operator!(const std::string_view &str)
|
|
{
|
|
return str.empty();
|
|
}
|
|
|
|
|
|
//
|
|
// Iterator based until() matching std::for_each except the function
|
|
// returns a bool to continue rather than void.
|
|
//
|
|
template<class it_a,
|
|
class it_b,
|
|
class boolean_function>
|
|
bool
|
|
until(it_a a,
|
|
const it_b &b,
|
|
boolean_function&& f)
|
|
{
|
|
for(; a != b; ++a)
|
|
if(!f(*a))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/// Convenience loop to test std::is* on a character sequence
|
|
template<int (&test)(int) = std::isprint>
|
|
ssize_t
|
|
ctype(const char *begin,
|
|
const char *const &end)
|
|
{
|
|
size_t i(0);
|
|
for(; begin != end; ++begin, ++i)
|
|
if(!test(static_cast<unsigned char>(*begin)))
|
|
return i;
|
|
|
|
return -1;
|
|
}
|
|
|
|
|
|
template<class lockable>
|
|
struct unlock_guard
|
|
{
|
|
lockable &l;
|
|
|
|
unlock_guard(lockable &l)
|
|
:l{l}
|
|
{
|
|
l.unlock();
|
|
}
|
|
|
|
~unlock_guard() noexcept
|
|
{
|
|
l.lock();
|
|
}
|
|
};
|
|
|
|
|
|
template<class T>
|
|
constexpr bool
|
|
is_bool()
|
|
{
|
|
using type = typename std::remove_reference<T>::type;
|
|
return std::is_same<type, bool>::value;
|
|
}
|
|
|
|
template<class T>
|
|
constexpr bool
|
|
is_number()
|
|
{
|
|
using type = typename std::remove_reference<T>::type;
|
|
return std::is_arithmetic<type>::value;
|
|
}
|
|
|
|
template<class T>
|
|
constexpr bool
|
|
is_floating()
|
|
{
|
|
using type = typename std::remove_reference<T>::type;
|
|
return is_number<T>() && std::is_floating_point<type>();
|
|
}
|
|
|
|
template<class T>
|
|
constexpr bool
|
|
is_integer()
|
|
{
|
|
return is_number<T>() && !is_floating<T>();
|
|
}
|
|
|
|
struct is_zero
|
|
{
|
|
template<class T>
|
|
typename std::enable_if
|
|
<
|
|
is_bool<T>(),
|
|
bool>::type
|
|
test(const bool &value)
|
|
const
|
|
{
|
|
return !value;
|
|
}
|
|
|
|
template<class T>
|
|
typename std::enable_if
|
|
<
|
|
is_integer<T>() &&
|
|
!is_bool<T>(),
|
|
bool>::type
|
|
test(const size_t &value)
|
|
const
|
|
{
|
|
return value == 0;
|
|
}
|
|
|
|
template<class T>
|
|
typename std::enable_if
|
|
<
|
|
is_floating<T>(),
|
|
bool>::type
|
|
test(const double &value)
|
|
const
|
|
{
|
|
return !(value > 0.0 || value < 0.0);
|
|
}
|
|
|
|
template<class T>
|
|
bool operator()(T&& t)
|
|
const
|
|
{
|
|
return test<T>(std::forward<T>(t));
|
|
}
|
|
};
|
|
|
|
|
|
constexpr bool
|
|
is_powerof2(const long long v)
|
|
{
|
|
return v && !(v & (v - 1LL));
|
|
}
|
|
|
|
|
|
} // namespace util
|
|
} // namespace ircd
|