contract FreezableToken is StandardToken {
// freezing chains
mapping (bytes32 => uint64) internal chains;
// freezing amounts for each chain
mapping (bytes32 => uint) internal freezings;
// total freezing balance per address
mapping (address => uint) internal freezingBalance;

event Freezed(address indexed to, uint64 release, uint amount);
event Released(address indexed owner, uint amount);

/**
* @dev Gets the balance of the specified address include freezing tokens.
* @param _owner The address to query the the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function balanceOf(address _owner) public view returns (uint256 balance) {
return super.balanceOf(_owner) + freezingBalance[_owner];
}

/**
* @dev Gets the balance of the specified address without freezing tokens.
* @param _owner The address to query the the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function actualBalanceOf(address _owner) public view returns (uint256 balance) {
return super.balanceOf(_owner);
}

function freezingBalanceOf(address _owner) public view returns (uint256 balance) {
return freezingBalance[_owner];
}

/**
* @dev gets freezing count
* @param _addr Address of freeze tokens owner.
*/
function freezingCount(address _addr) public view returns (uint count) {
uint64 release = chains[toKey(_addr, 0)];
while (release != 0) {
count++;
release = chains[toKey(_addr, release)];
}
}

/**
* @dev gets freezing end date and freezing balance for the freezing portion specified by index.
* @param _addr Address of freeze tokens owner.
* @param _index Freezing portion index. It ordered by release date descending.
*/
function getFreezing(address _addr, uint _index) public view returns (uint64 _release, uint _balance) {
for (uint i = 0; i < _index + 1; i++) {
_release = chains[toKey(_addr, _release)];
if (_release == 0) {
return;
}
}
_balance = freezings[toKey(_addr, _release)];
}

/**
* @dev freeze your tokens to the specified address.
* Be careful, gas usage is not deterministic,
* and depends on how many freezes _to address already has.
* @param _to Address to which token will be freeze.
* @param _amount Amount of token to freeze.
* @param _until Release date, must be in future.
*/
function freezeTo(address _to, uint _amount, uint64 _until) public {
require(_to != address(0));
require(_amount <= balances[msg.sender]);

balances[msg.sender] = balances[msg.sender].sub(_amount);

bytes32 currentKey = toKey(_to, _until);
freezings[currentKey] = freezings[currentKey].add(_amount);
freezingBalance[_to] = freezingBalance[_to].add(_amount);

freeze(_to, _until);
emit Transfer(msg.sender, _to, _amount);
emit Freezed(_to, _until, _amount);
}

/**
* @dev release first available freezing tokens.
*/
function releaseOnce() public {
bytes32 headKey = toKey(msg.sender, 0);
uint64 head = chains[headKey];
require(head != 0);
require(uint64(block.timestamp) > head);
bytes32 currentKey = toKey(msg.sender, head);

uint64 next = chains[currentKey];

uint amount = freezings[currentKey];
delete freezings[currentKey];

balances[msg.sender] = balances[msg.sender].add(amount);
freezingBalance[msg.sender] = freezingBalance[msg.sender].sub(amount);

if (next == 0) {
delete chains[headKey];
} else {
chains[headKey] = next;
delete chains[currentKey];
}
emit Released(msg.sender, amount);
}

/**
* @dev release all available for release freezing tokens. Gas usage is not deterministic!
* @return how many tokens was released
*/
function releaseAll() public returns (uint tokens) {
uint release;
uint balance;
(release, balance) = getFreezing(msg.sender, 0);
while (release != 0 && block.timestamp > release) {
releaseOnce();
tokens += balance;
(release, balance) = getFreezing(msg.sender, 0);
}
}

function toKey(address _addr, uint _release) internal pure returns (bytes32 result) {
// masc to increase entropy
result = 0x5749534800000000000000000000000000000000000000000000000000000000;
assembly {
result := or(result, mul(_addr, 0x10000000000000000))
result := or(result, _release)
}
}

function freeze(address _to, uint64 _until) internal {
require(_until > block.timestamp);
bytes32 key = toKey(_to, _until);
bytes32 parentKey = toKey(_to, uint64(0));
uint64 next = chains[parentKey];

if (next == 0) {
chains[parentKey] = _until;
return;
}

bytes32 nextKey = toKey(_to, next);
uint parent;

while (next != 0 && _until > next) {
parent = next;
parentKey = nextKey;

next = chains[nextKey];
nextKey = toKey(_to, next);
}

if (_until == next) {
return;
}

if (next != 0) {
chains[key] = next;
}

chains[parentKey] = _until;
}
}
function getFreezing(address _addr, uint _index) public view returns (uint64 _release, uint _balance) {
for (uint i = 0; i < _index + 1; i++) {
_release = chains[toKey(_addr, _release)];
if (_release == 0) {
return;
}
}
_balance = freezings[toKey(_addr, _release)];
}

/**
 * @dev gets freezing end date and freezing balance for the freezing portion specified by index.
 * @param _addr Address of freeze tokens owner.
 * @param _index Freezing portion index. It ordered by release date descending.
 */