Contract Source Code:

// This software is a subject to Ambisafe License Agreement.
// No use or distribution is allowed without written permission from Ambisafe.
// https://ambisafe.com/terms.pdf

contract EventsHistory {
    function versions(address) constant returns(uint);
}

/**
 * @title MultiAsset Emitter.
 *
 * Contains all the original event emitting function definitions and events.
 * In case of new events needed later, additional emitters can be developed.
 * All the functions is meant to be called using delegatecall.
 */
library MultiAssetEmitter {
    event Transfer(address indexed from, address indexed to, bytes32 indexed symbol, uint value, string reference, uint version);
    event Issue(bytes32 indexed symbol, uint value, address by, uint version);
    event Revoke(bytes32 indexed symbol, uint value, address by, uint version);
    event OwnershipChange(address indexed from, address indexed to, bytes32 indexed symbol, uint version);
    event Approve(address indexed from, address indexed spender, bytes32 indexed symbol, uint value, uint version);
    event Recovery(address indexed from, address indexed to, address by, uint version);
    event TransferToICAP(address indexed from, address indexed to, bytes32 indexed icap, uint value, string reference, uint version);
    event Error(bytes32 message, uint version);
    
    function emitTransfer(address _from, address _to, bytes32 _symbol, uint _value, string _reference) {
        Transfer(_from, _to, _symbol, _value, _reference, _getVersion());
    }

    function emitIssue(bytes32 _symbol, uint _value, address _by) {
        Issue(_symbol, _value, _by, _getVersion());
    }

    function emitRevoke(bytes32 _symbol, uint _value, address _by) {
        Revoke(_symbol, _value, _by, _getVersion());
    }

    function emitOwnershipChange(address _from, address _to, bytes32 _symbol) {
        OwnershipChange(_from, _to, _symbol, _getVersion());
    }

    function emitApprove(address _from, address _spender, bytes32 _symbol, uint _value) {
        Approve(_from, _spender, _symbol, _value, _getVersion());
    }

    function emitRecovery(address _from, address _to, address _by) {
        Recovery(_from, _to, _by, _getVersion());
    }

    function emitTransferToICAP(address _from, address _to, bytes32 _icap, uint _value, string _reference) {
        TransferToICAP(_from, _to, _icap, _value, _reference, _getVersion());
    }

    function emitError(bytes32 _message) {
        Error(_message, _getVersion());
    }

    /**
     * Get version number of the caller.
     *
     * Assuming that the call is made by EventsHistory using delegate call,
     * context was not changed, so the caller is the address that called
     * EventsHistory.
     *
     * @return current context caller version number.
     */
    function _getVersion() constant internal returns(uint) {
        return EventsHistory(address(this)).versions(msg.sender);
    }
}