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construct/include/ircd/ctx/parallel.h

138 lines
2.3 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 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. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_CTX_PARALLEL_H
namespace ircd::ctx
{
template<class arg> class parallel;
}
template<class arg>
struct ircd::ctx::parallel
{
using closure = std::function<void (arg &)>;
pool *p {nullptr};
vector_view<arg> a;
closure c;
dock d;
std::exception_ptr eptr;
ushort snd {0};
ushort rcv {0};
ushort out {0};
void receiver() noexcept;
public:
void wait_avail();
void wait_done();
void operator()();
void operator()(const arg &a);
parallel(pool &, const vector_view<arg> &, closure);
~parallel() noexcept;
};
template<class arg>
ircd::ctx::parallel<arg>::parallel(pool &p,
const vector_view<arg> &a,
closure c)
:p{&p}
,a{a}
,c{std::move(c)}
{
p.min(this->a.size());
}
template<class arg>
ircd::ctx::parallel<arg>::~parallel()
noexcept
{
const uninterruptible::nothrow ui;
wait_done();
}
template<class arg>
void
ircd::ctx::parallel<arg>::operator()(const arg &a)
{
if(this->eptr)
std::rethrow_exception(this->eptr);
auto &p(*this->p);
p(std::bind(&parallel::receiver, this));
this->a.at(snd++) = a;
snd %= this->a.size();
out++;
wait_avail();
}
template<class arg>
void
ircd::ctx::parallel<arg>::operator()()
{
if(this->eptr)
std::rethrow_exception(this->eptr);
auto &p(*this->p);
p(std::bind(&parallel::receiver, this));
snd++;
snd %= this->a.size();
out++;
wait_avail();
}
template<class arg>
void
ircd::ctx::parallel<arg>::receiver()
noexcept
{
auto &a
{
this->a.at(rcv++ % this->a.size())
};
if(!this->eptr) try
{
c(a);
}
catch(...)
{
this->eptr = std::current_exception();
}
out--;
d.notify_one();
}
template<class arg>
void
ircd::ctx::parallel<arg>::wait_avail()
{
d.wait([this]
{
return out < a.size();
});
}
template<class arg>
void
ircd::ctx::parallel<arg>::wait_done()
{
d.wait([this]
{
return !out;
});
}