// ------------------------------------------------------------------------------
// This file is part of netvote.
//
// netvote 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.
//
// netvote 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 solidity.  If not, see <http://www.gnu.org/licenses/>
//
// (c) 2017 netvote contributors.
//------------------------------------------------------------------------------

pragma solidity ^0.4.17;


/**
 * @title AddressSet
 * @dev iterable map of addresses that modifies size upon removal
 * Note that the order changes upon removal.
 */
library AddressSet {

    struct SetData {
        mapping(address => bool) entryExists;
        mapping(address => uint256) entryIndex;
        address[] entries;
    }

    function indexOf(SetData storage self, address a) public constant returns (uint256) {
        return self.entryIndex[a];
    }

    function getAt(SetData storage self, uint256 index) public constant returns (address) {
        return self.entries[index];
    }

    function contains(SetData storage self, address a) public constant returns (bool) {
        return self.entryExists[a];
    }

    function size(SetData storage self) public constant returns (uint256) {
        return self.entries.length;
    }

    function put(SetData storage self, address a) public {
        if (!self.entryExists[a]) {
            self.entryExists[a] = true;
            self.entries.push(a);
            self.entryIndex[a] = self.entries.length - 1;
        }
    }

    function remove(SetData storage self, address a) public {
        if (self.entryExists[a]) {
            uint256 index = self.entryIndex[a];
            // if not last entry, copy last entry into a's slot
            if (index < size(self) - 1) {
                address lastEntry = self.entries[size(self)-1];
                self.entries[index] = lastEntry;
                self.entryIndex[lastEntry] = index;
            }
            // resize array
            self.entries.length--;
            delete self.entryExists[a];
            delete self.entryIndex[a];
        }
    }
}