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pragma solidity ^0.4.11;
import "../Events/Event.sol";
/// @title Scalar event contract - Scalar events resolve to a number within a range
/// @author Stefan George - <stefan@gnosis.pm>
contract ScalarEvent is Event {
using Math for *;
/*
* Constants
*/
uint8 public constant SHORT = 0;
uint8 public constant LONG = 1;
uint24 public constant OUTCOME_RANGE = 1000000;
/*
* Storage
*/
int public lowerBound;
int public upperBound;
/*
* Public functions
*/
/// @dev Contract constructor validates and sets basic event properties
/// @param _collateralToken Tokens used as collateral in exchange for outcome tokens
/// @param _oracle Oracle contract used to resolve the event
/// @param _lowerBound Lower bound for event outcome
/// @param _upperBound Lower bound for event outcome
function ScalarEvent(
Token _collateralToken,
Oracle _oracle,
int _lowerBound,
int _upperBound
)
public
Event(_collateralToken, _oracle, 2)
{
// Validate bounds
require(_upperBound > _lowerBound);
lowerBound = _lowerBound;
upperBound = _upperBound;
}
/// @dev Exchanges sender's winning outcome tokens for collateral tokens
/// @return Sender's winnings
function redeemWinnings()
public
returns (uint winnings)
{
// Winning outcome has to be set
require(isOutcomeSet);
// Calculate winnings
uint24 convertedWinningOutcome;
// Outcome is lower than defined lower bound
if (outcome < lowerBound)
convertedWinningOutcome = 0;
// Outcome is higher than defined upper bound
else if (outcome > upperBound)
convertedWinningOutcome = OUTCOME_RANGE;
// Map outcome to outcome range
else
convertedWinningOutcome = uint24(OUTCOME_RANGE * (outcome - lowerBound) / (upperBound - lowerBound));
uint factorShort = OUTCOME_RANGE - convertedWinningOutcome;
uint factorLong = OUTCOME_RANGE - factorShort;
uint shortOutcomeTokenCount = outcomeTokens[SHORT].balanceOf(msg.sender);
uint longOutcomeTokenCount = outcomeTokens[LONG].balanceOf(msg.sender);
winnings = shortOutcomeTokenCount.mul(factorShort).add(longOutcomeTokenCount.mul(factorLong)) / OUTCOME_RANGE;
// Revoke all outcome tokens
outcomeTokens[SHORT].revoke(msg.sender, shortOutcomeTokenCount);
outcomeTokens[LONG].revoke(msg.sender, longOutcomeTokenCount);
// Payout winnings to sender
require(collateralToken.transfer(msg.sender, winnings));
WinningsRedemption(msg.sender, winnings);
}
/// @dev Calculates and returns event hash
/// @return Event hash
function getEventHash()
public
constant
returns (bytes32)
{
return keccak256(collateralToken, oracle, lowerBound, upperBound);
}
}
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