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/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2022 Sadie Powell <sadie@witchery.services>
*
* This file is part of InspIRCd. InspIRCd 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, version 2.
*
* This program 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
namespace insp::map
{
/** Compares two maps and returns a list of the differences.
* @param first The first map to compare.
* @param second The second map to compare.
* @param out The map to store the differences in.
*/
template<typename Key, typename Value, typename Compare, template<typename...> typename Map>
void difference(const Map<Key, Value, Compare>& first, const Map<Key, Value, Compare>& second,
Map<Key, std::pair<std::optional<Value>, std::optional<Value>>, Compare>& out)
{
auto fiter = first.cbegin();
auto siter = second.cbegin();
while (fiter != first.end())
{
if (siter == second.end())
{
// Store the remaining from the first.
while (fiter != first.end())
{
out[fiter->first] = { fiter->second, std::nullopt };
fiter++;
}
return;
}
if (fiter->first < siter->first)
{
// The key in first is not in second.
out[fiter->first] = { fiter->second, std::nullopt };
fiter++;
}
else if (siter->first < fiter->first)
{
// The key in second is not in first.
out[siter->first] = { std::nullopt, siter->second };
siter++;
}
else if (fiter->second != siter->second)
{
// The key exists in both but the value differs.
out[fiter->first] = { fiter->second, siter->second };
fiter++;
siter++;
}
else
{
// The key/value is identical in both.
fiter++;
siter++;
}
}
// Store the remaining from the second.
while (siter != second.end())
{
out[siter->first] = { std::nullopt, siter->second };
siter++;
}
}
}
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