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construct/include/ircd/util.h
2017-03-17 20:05:36 -07:00

530 lines
14 KiB
C++

/*
* charybdis: 21st Century IRC++d
* util.h: Miscellaneous utilities
*
* Copyright (C) 2016 Charybdis Development Team
* Copyright (C) 2016 Jason Volk <jason@zemos.net>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice is present in all copies.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
#pragma once
#define HAVE_IRCD_UTIL_H
namespace ircd {
inline namespace util {
#define IRCD_EXPCAT(a, b) a ## b
#define IRCD_CONCAT(a, b) IRCD_EXPCAT(a, b)
#define IRCD_UNIQUE(a) IRCD_CONCAT(a, __COUNTER__)
#define IRCD_OVERLOAD(NAME) \
struct NAME##_t {}; \
static constexpr NAME##_t NAME {};
#define IRCD_WEAK_TYPEDEF(TYPE, NAME) \
struct NAME \
:TYPE \
{ \
using TYPE::TYPE; \
};
#define IRCD_STRONG_TYPEDEF(TYPE, NAME) \
struct NAME \
{ \
TYPE val; \
\
explicit operator const TYPE &() const { return val; } \
explicit operator TYPE &() { return val; } \
};
#define IRCD_WEAK_T(TYPE) \
IRCD_WEAK_TYPEDEF(TYPE, IRCD_UNIQUE(weak_t))
// ex: using foo_t = IRCD_STRONG_T(int)
#define IRCD_STRONG_T(TYPE) \
IRCD_STRONG_TYPEDEF(TYPE, IRCD_UNIQUE(strong_t))
template<class T>
using custom_ptr = std::unique_ptr<T, std::function<void (T *) noexcept>>;
struct scope
{
struct uncaught;
const std::function<void ()> func;
template<class F>
scope(F &&func)
:func(std::forward<F>(func))
{}
scope(const scope &) = delete;
~scope() noexcept
{
func();
}
};
struct scope::uncaught
{
const std::function<void ()> func;
template<class F>
uncaught(F &&func)
:func(std::forward<F>(func))
{}
uncaught(const uncaught &) = delete;
~uncaught() noexcept
{
if(unlikely(std::uncaught_exception()))
func();
}
};
// For conforming enums include a _NUM_ as the last element,
// then num_of<my_enum>() works
template<class Enum>
constexpr
typename std::underlying_type<Enum>::type
num_of()
{
return static_cast<typename std::underlying_type<Enum>::type>(Enum::_NUM_);
}
// Iteration of a num_of() conforming enum
template<class Enum>
typename std::enable_if<std::is_enum<Enum>::value, void>::type
for_each(const std::function<void (const Enum &)> &func)
{
for(size_t i(0); i < num_of<Enum>(); ++i)
func(static_cast<Enum>(i));
}
/**
* flag-enum utilities
*
* This relaxes the strong typing of enums to allow bitflags with operations on the elements
* with intuitive behavior.
*
* If the project desires absolute guarantees on the strong enum typing then this can be tucked
* away in some namespace and imported into select scopes instead.
*/
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
operator~(const Enum &a)
{
using enum_t = typename std::underlying_type<Enum>::type;
return static_cast<Enum>(~static_cast<enum_t>(a));
}
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, bool>::type
operator!(const Enum &a)
{
using enum_t = typename std::underlying_type<Enum>::type;
return !static_cast<enum_t>(a);
}
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
operator|(const Enum &a, const Enum &b)
{
using enum_t = typename std::underlying_type<Enum>::type;
return static_cast<Enum>(static_cast<enum_t>(a) | static_cast<enum_t>(b));
}
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
operator&(const Enum &a, const Enum &b)
{
using enum_t = typename std::underlying_type<Enum>::type;
return static_cast<Enum>(static_cast<enum_t>(a) & static_cast<enum_t>(b));
}
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, Enum>::type
operator^(const Enum &a, const Enum &b)
{
using enum_t = typename std::underlying_type<Enum>::type;
return static_cast<Enum>(static_cast<enum_t>(a) ^ static_cast<enum_t>(b));
}
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, Enum &>::type
operator|=(Enum &a, const Enum &b)
{
using enum_t = typename std::underlying_type<Enum>::type;
return (a = (a | b));
}
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, Enum &>::type
operator&=(Enum &a, const Enum &b)
{
using enum_t = typename std::underlying_type<Enum>::type;
return (a = (a & b));
}
template<class Enum>
constexpr
typename std::enable_if<std::is_enum<Enum>::value, Enum &>::type
operator^=(Enum &a, const Enum &b)
{
using enum_t = typename std::underlying_type<Enum>::type;
return (a = (a ^ b));
}
inline size_t
size(std::ostream &s)
{
const auto cur(s.tellp());
s.seekp(0, std::ios::end);
const auto ret(s.tellp());
s.seekp(cur, std::ios::beg);
return ret;
}
inline std::pair<time_t, int32_t>
microtime()
{
struct timeval tv;
gettimeofday(&tv, nullptr);
return { tv.tv_sec, tv.tv_usec };
}
inline ssize_t
microtime(char *const &buf,
const size_t &size)
{
const auto mt(microtime());
return snprintf(buf, size, "%zd.%06d", mt.first, mt.second);
}
template<class T>
auto
string(const T &s)
{
std::stringstream ss;
return static_cast<std::stringstream &>(ss << s).str();
}
inline auto
string(const char *const &buf, const size_t &size)
{
return std::string{buf, size};
}
inline auto
string(const uint8_t *const &buf, const size_t &size)
{
return string(reinterpret_cast<const char *>(buf), size);
}
inline auto
operator!(const std::string &str)
{
return str.empty();
}
constexpr size_t
hash(const char *const &str,
const size_t i = 0)
{
return !str[i]? 7681ULL : (hash(str, i+1) * 33ULL) ^ str[i];
}
inline size_t
hash(const std::string_view &str,
const size_t i = 0)
{
return i >= str.size()? 7681ULL : (hash(str, i+1) * 33ULL) ^ str.at(i);
}
inline size_t
hash(const std::string &str,
const size_t i = 0)
{
return i >= str.size()? 7681ULL : (hash(str, i+1) * 33ULL) ^ str.at(i);
}
constexpr size_t
hash(const char16_t *const &str,
const size_t i = 0)
{
return !str[i]? 7681ULL : (hash(str, i+1) * 33ULL) ^ str[i];
}
inline size_t
hash(const std::u16string &str,
const size_t i = 0)
{
return i >= str.size()? 7681ULL : (hash(str, i+1) * 33ULL) ^ str.at(i);
}
/***
* C++14 user defined literals
*
* These are very useful for dealing with space. Simply write 8_MiB and it's
* as if a macro turned that into (8 * 1024 * 1024) at compile time.
*/
#define IRCD_UNIT_LITERAL_LL(name, morphism) \
constexpr auto \
operator"" _ ## name(const unsigned long long val) \
{ \
return (morphism); \
}
#define IRCD_UNIT_LITERAL_LD(name, morphism) \
constexpr auto \
operator"" _ ## name(const long double val) \
{ \
return (morphism); \
}
// IEC unit literals
IRCD_UNIT_LITERAL_LL( B, val )
IRCD_UNIT_LITERAL_LL( KiB, val * 1024LL )
IRCD_UNIT_LITERAL_LL( MiB, val * 1024LL * 1024LL )
IRCD_UNIT_LITERAL_LL( GiB, val * 1024LL * 1024LL * 1024LL )
IRCD_UNIT_LITERAL_LL( TiB, val * 1024LL * 1024LL * 1024LL * 1024LL )
IRCD_UNIT_LITERAL_LL( PiB, val * 1024LL * 1024LL * 1024LL * 1024LL * 1024LL )
IRCD_UNIT_LITERAL_LL( EiB, val * 1024LL * 1024LL * 1024LL * 1024LL * 1024LL * 1024LL )
IRCD_UNIT_LITERAL_LD( B, val )
IRCD_UNIT_LITERAL_LD( KiB, val * 1024.0L )
IRCD_UNIT_LITERAL_LD( MiB, val * 1024.0L * 1024.0L )
IRCD_UNIT_LITERAL_LD( GiB, val * 1024.0L * 1024.0L * 1024.0L )
IRCD_UNIT_LITERAL_LD( TiB, val * 1024.0L * 1024.0L * 1024.0L * 1024.0L )
IRCD_UNIT_LITERAL_LD( PiB, val * 1024.0L * 1024.0L * 1024.0L * 1024.0L * 1024.0L )
IRCD_UNIT_LITERAL_LD( EiB, val * 1024.0L * 1024.0L * 1024.0L * 1024.0L * 1024.0L * 1024.0L )
// SI unit literals
IRCD_UNIT_LITERAL_LL( KB, val * 1000LL )
IRCD_UNIT_LITERAL_LL( MB, val * 1000LL * 1000LL )
IRCD_UNIT_LITERAL_LL( GB, val * 1000LL * 1000LL * 1000LL )
IRCD_UNIT_LITERAL_LL( TB, val * 1000LL * 1000LL * 1000LL * 1000LL )
IRCD_UNIT_LITERAL_LL( PB, val * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL )
IRCD_UNIT_LITERAL_LL( EB, val * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL )
IRCD_UNIT_LITERAL_LD( KB, val * 1000.0L )
IRCD_UNIT_LITERAL_LD( MB, val * 1000.0L * 1000.0L )
IRCD_UNIT_LITERAL_LD( GB, val * 1000.0L * 1000.0L * 1000.0L )
IRCD_UNIT_LITERAL_LD( TB, val * 1000.0L * 1000.0L * 1000.0L * 1000.0L )
IRCD_UNIT_LITERAL_LD( PB, val * 1000.0L * 1000.0L * 1000.0L * 1000.0L * 1000.0L )
IRCD_UNIT_LITERAL_LD( EB, val * 1000.0L * 1000.0L * 1000.0L * 1000.0L * 1000.0L * 1000.0L )
/* Output the sizeof a structure at compile time.
* This stops the compiler with an error (good) containing the size of the target
* in the message.
*
* example: struct foo {}; IRCD_TEST_SIZEOF(foo)
*/
template<size_t SIZE>
struct _TEST_SIZEOF_;
#define IRCD_TEST_SIZEOF(name) \
ircd::util::_TEST_SIZEOF_<sizeof(name)> _test_;
/* This is a template alternative to nothrow overloads, which
* allows keeping the function arguments sanitized of the thrownness.
*/
template<class exception_t>
constexpr bool
is_nothrow()
{
return std::is_same<exception_t, std::nothrow_t>::value;
}
template<class exception_t = std::nothrow_t,
class return_t = bool>
using nothrow_overload = typename std::enable_if<is_nothrow<exception_t>(), return_t>::type;
template<class exception_t,
class return_t = void>
using throw_overload = typename std::enable_if<!is_nothrow<exception_t>(), return_t>::type;
//
// Test if type is forward declared or complete
//
template<class T,
class = void>
struct is_complete
:std::false_type
{
};
template<class T>
struct is_complete<T, decltype(void(sizeof(T)))>
:std::true_type
{
};
//
// Convenience constexprs for iterators
//
template<class It>
constexpr auto
is_iterator()
{
return std::is_base_of<typename std::iterator_traits<It>::value_type, It>::value;
}
template<class It>
constexpr auto
is_forward_iterator()
{
return std::is_base_of<std::forward_iterator_tag, typename std::iterator_traits<It>::iterator_category>::value;
}
template<class It>
constexpr auto
is_input_iterator()
{
return std::is_base_of<std::forward_iterator_tag, typename std::iterator_traits<It>::iterator_category>::value;
}
// std::next with out_of_range exception
template<class It>
typename std::enable_if<is_forward_iterator<It>() || is_input_iterator<It>(), It>::type
at(It &&start,
It &&stop,
ssize_t i)
{
for(; start != stop; --i, std::advance(start, 1))
if(!i)
return start;
throw std::out_of_range("at(a, b, i): 'i' out of range");
}
struct string_view
:std::string_view
{
// (non-standard) our faux insert stub
void insert(const iterator &, const char &) { assert(1); } //XXX
// (non-standard) our iterator-based assign
string_view &assign(const char *const &begin, const char *const &end)
{
*this = std::string_view{begin, size_t(std::distance(begin, end))};
return *this;
}
// (non-standard) our iterator-based constructor
string_view(const char *const &begin, const char *const &end)
:std::string_view{begin, size_t(std::distance(begin, end))}
{}
// Required due to current instability in stdlib
//string_view(const std::experimental::string_view &esv)
//:std::string_view{esv}
//{}
// Required due to current instability in stdlib
string_view(const std::experimental::fundamentals_v1::basic_string_view<char> &bsv)
:std::string_view{bsv}
{}
string_view()
:std::string_view{}
{}
using std::string_view::string_view;
};
template<class function,
class... args>
auto
syscall(function&& f,
args&&... a)
{
const auto ret(f(a...));
if(unlikely(long(ret) == -1))
throw std::system_error(errno, std::system_category());
return ret;
}
struct va_rtti
:std::array<std::pair<const void *, const std::type_info *>, 8>
{
size_t argc;
size_t size() const
{
return argc;
}
template<class... Args>
va_rtti(Args&&... args)
:std::array<std::pair<const void *, const std::type_info *>, 8>
{{
std::make_pair(std::addressof(args), std::addressof(typeid(Args)))...
}}
,argc
{
sizeof...(args)
}{}
};
} // namespace util
} // namespace ircd