tdesktop/Telegram/SourceFiles/rpl/range.h

/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org

Telegram Desktop is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

It is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.

Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#pragma once

#include <rpl/producer.h>

namespace rpl {

template <typename Value, typename Error = no_error>
inline producer<std::decay_t<Value>, Error> single(Value &&value) {
	using consumer_t = consumer<std::decay_t<Value>, Error>;
	return [value = std::forward<Value>(value)](
			const consumer_t &consumer) mutable {
		consumer.put_next(std::move(value));
		consumer.put_done();
		return lifetime();
	};
}

template <typename Error = no_error>
inline producer<empty_value, Error> single() {
	return [](const consumer<empty_value, Error> &consumer) {
		consumer.put_next({});
		consumer.put_done();
		return lifetime();
	};
}

template <typename Value, typename Error = no_error>
inline producer<Value, Error> vector(std::vector<Value> &&values) {
	return [values = std::move(values)](
			const consumer<Value, Error> &consumer) mutable {
		for (auto &value : values) {
			consumer.put_next(std::move(value));
		}
		consumer.put_done();
		return lifetime();
	};
}

template <typename Error = no_error>
inline producer<bool, Error> vector(std::vector<bool> &&values) {
	return [values = std::move(values)](
			const consumer<bool, Error> &consumer) mutable {
		for (auto value : values) {
			consumer.put_next_copy(value);
		}
		consumer.put_done();
		return lifetime();
	};
}

template <typename Value, typename Error = no_error, typename Range>
inline producer<Value, Error> range(Range &&range) {
	return vector(std::vector<Value>(
		std::begin(range),
		std::end(range)));
}

inline producer<int> ints(int from, int till) {
	Expects(from <= till);
	return [from, till](const consumer<int> &consumer) {
		for (auto i = from; i != till; ++i) {
			consumer.put_next_copy(i);
		}
		consumer.put_done();
		return lifetime();
	};
}

inline producer<int> ints(int count) {
	return ints(0, count);
}

} // namespace rpl