Pretty cosmetic

Pretty cosmetic

1. In function calculatePurchaseReturn:
   - Change '/ resD' to '>> PRECISION'
   - Change '/ 0x100000000' to '>> PRECISION'
2. In function calculateSaleReturn:
   - Change '/ 0x100000000' to '>> PRECISION'
3. In function fixedLog2:
   - Get rid of the 'lo' variable and all related operations, since the input is necessarily larger than or equal to "fixedOne", which yields 'lo = 0'

pragma solidity ^0.4.11;
import './SafeMath.sol';
import './IBancorFormula.sol';

/*
    Open issues:
    - The formula is not yet super accurate, especially for very small/very high ratios
    - Possibly support dynamic precision in the future
*/

contract BancorFormula is IBancorFormula, SafeMath {
    uint8 constant PRECISION = 32;  // fractional bits

    string public version = '0.1';

    function BancorFormula() {
    }

    /**
        @dev given a token supply, reserve, CRR and a deposit amount (in the reserve token), calculates the return for a given change (in the main token)

        Formula:
        Return = _supply * ((1 + _depositAmount / _reserveBalance) ^ (_reserveRatio / 100) - 1)

        @param _supply             token total supply
        @param _reserveBalance     total reserve
        @param _reserveRatio       constant reserve ratio, 1-100
        @param _depositAmount      deposit amount, in reserve token

        @return purchase return amount
    */
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _depositAmount) public constant returns (uint256) {
        // validate input
        require(_supply != 0 && _reserveBalance != 0 && _reserveRatio > 0 && _reserveRatio <= 100);

        // special case for 0 deposit amount
        if (_depositAmount == 0)
            return 0;

        uint256 baseN = safeAdd(_depositAmount, _reserveBalance);
        uint256 temp;

        // special case if the CRR = 100
        if (_reserveRatio == 100) {
            temp = safeMul(_supply, baseN) / _reserveBalance;
            return safeSub(temp, _supply);
        }

        var resN = power(baseN, _reserveBalance, _reserveRatio, 100);
        temp = safeMul(_supply, resN) >> PRECISION;
        var result = safeSub(temp, _supply);

        //From the result, we deduct the minimal increment, which is a
        // function of S and precision.
        return safeSub(result, _supply >> PRECISION);
     }

    /**
        @dev given a token supply, reserve, CRR and a sell amount (in the main token), calculates the return for a given change (in the reserve token)

        Formula:
        Return = _reserveBalance * (1 - (1 - _sellAmount / _supply) ^ (1 / (_reserveRatio / 100)))

        @param _supply             token total supply
        @param _reserveBalance     total reserve
        @param _reserveRatio       constant reserve ratio, 1-100
        @param _sellAmount         sell amount, in the token itself

        @return sale return amount
    */
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _sellAmount) public constant returns (uint256) {
        // validate input
        require(_supply != 0 && _reserveBalance != 0 && _reserveRatio > 0 && _reserveRatio <= 100 && _sellAmount <= _supply);

        // special case for 0 sell amount
        if (_sellAmount == 0)
            return 0;

        uint256 baseN = safeSub(_supply, _sellAmount);
        uint256 temp1;
        uint256 temp2;

        // special case if the CRR = 100
        if (_reserveRatio == 100) {
            temp1 = safeMul(_reserveBalance, _supply);
            temp2 = safeMul(_reserveBalance, baseN);
            return safeSub(temp1, temp2) / _supply;
        }

        // special case for selling the entire supply
        if (_sellAmount == _supply)
            return _reserveBalance;

        var resD = uint256(1) << PRECISION;
        var resN = powerRoundDown(_supply, baseN, 100, _reserveRatio);
        temp1 = safeMul(_reserveBalance, resN);
        temp2 = safeMul(_reserveBalance, resD);

        var result = safeSub(temp1, temp2) / resN;
        //From the result, we deduct the minimal increment, which is a
        // function of R and precision.
        return safeSub(result, _reserveBalance >> PRECISION);
    }

    /**
        @dev Calculate (_baseN / _baseD) ^ (_expN / _expD)
        Returns result upshifted by PRECISION

        This method is overflow-safe
    */
    function power(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) constant returns (uint256 resN) {
        uint256 logbase = ln(_baseN, _baseD);
        // Not using safeDiv here, since safeDiv protects against
        // precision loss. It's unavoidable, however
        // Both `ln` and `fixedExp` are overflow-safe.
        resN = fixedExp(safeMul(logbase, _expN) / _expD);

        return resN;
	}
    /**
        @dev Calculate (_baseN / _baseD) ^ (_expN / _expD)
        This mehthod is skewed to make the precision loss error decrease the result
        Returns result upshifted by PRECISION

        This method is overflow-safe
    */
    function powerRoundDown(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) constant returns (uint256 resN) {

        // In `ln`, the log of numerator and denominator are subtracted:
        // log(n)-log(d) . To ensure that the precision loss is in the right
        // direction, we subtract one unit
        // Reasoning:
        //      floor(log(d)) +1 == ceil(log(d))
        uint256 logbase = ln(_baseN, _baseD);
        if (logbase > 1)
            logbase -= 1;

        // Not using safeDiv here, since safeDiv protects against
        // precision loss. It's unavoidable, however
        // Both `ln` and `fixedExp` are overflow-safe.
        resN = fixedExp(safeMul(logbase, _expN) / _expD);
        return resN;
    }

    /**
        input range:
            - numerator: [1, uint256_max >> PRECISION]
            - denominator: [1, uint256_max >> PRECISION]
        output range:
            [0, 0x9b43d4f8d6]

        This method asserts outside of bounds

    */
    function ln(uint256 _numerator, uint256 _denominator) constant returns (uint256) {
        // denominator > numerator: less than one yields negative values. Unsupported
        assert(_denominator <= _numerator);

        // log(1) is the lowest we can go
        assert(_denominator != 0 && _numerator != 0);

        // Upper 32 bits are scaled off by PRECISION
        assert(_numerator & 0xffffffff00000000000000000000000000000000000000000000000000000000 == 0);
        assert(_denominator & 0xffffffff00000000000000000000000000000000000000000000000000000000 == 0);

        return fixedLoge(_numerator << PRECISION) - fixedLoge(_denominator << PRECISION);
    }

    /**
        input range:
            [0x100000000,uint256_max]
        output range:
            [0, 0x9b43d4f8d6]

        This method asserts outside of bounds

    */
    function fixedLoge(uint256 _x) constant returns (uint256 logE) {
        /*
        Since `fixedLog2` output range is max `0xdfffffffff`
        (40 bits, or 5 bytes), we can use a very large approximation
        for `ln(2)`. This one is used since it's the max accuracy
        of Python `ln(2)`

        0xb17217f7d1cf78 = ln(2) * (1 << 56)

        */
        //Cannot represent negative numbers (below 1)
        assert(_x >= 0x100000000);

        uint256 log2 = fixedLog2(_x);
        logE = (log2 * 0xb17217f7d1cf78) >> 56;
    }

    /**
        Returns log2(x >> 32) << 32
        So x is assumed to be already upshifted 32 bits, and
        the result is also upshifted 32 bits.

        input-range :
            [0x100000000,uint256_max]
        output-range:
            [0,0xdfffffffff]

        This method asserts outside of bounds

    */
    function fixedLog2(uint256 _x) constant returns (uint256) {
        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 fixedTwo = uint256(2) << PRECISION;

        // Numbers below 1 are negative.
        assert( _x >= fixedOne);
        //if (_x < fixedTwo) {
        //    if (_x >= fixedOne){
        //        return 0;
        //    }
        //    assert(false);
        //}

        uint256 hi = 0;

        while (_x >= fixedTwo) {
            _x >>= 1;
            hi += fixedOne;
        }

        for (uint8 i = 0; i < PRECISION; ++i) {
            _x = (_x * _x) >> PRECISION;
            if (_x >= fixedTwo) {
                _x >>= 1;
                hi += uint256(1) << (PRECISION - 1 - i);
            }
        }

        return hi;
    }

    /**
        fixedExp is a 'protected' version of `fixedExpUnsafe`, which
        asserts instead of overflows
    */
    function fixedExp(uint256 _x) constant returns (uint256) {
        assert(_x <= 0x386bfdba29);
        return fixedExpUnsafe(_x);
    }

    /**
        fixedExp
        Calculates e^x according to maclauren summation:

        e^x = 1+x+x^2/2!...+x^n/n!

        and returns e^(x>>32) << 32, that is, upshifted for accuracy

        Input range:
            - Function ok at    <= 242329958953
            - Function fails at >= 242329958954

        This method is is visible for testcases, but not meant for direct use.
    */
    function fixedExpUnsafe(uint256 _x) constant returns (uint256) {
        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 xi = fixedOne;
        uint256 res = 0xde1bc4d19efcac82445da75b00000000 * xi;

        xi = (xi * _x) >> PRECISION;
        res += xi * 0xde1bc4d19efcb0000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x6f0de268cf7e58000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x2504a0cd9a7f72000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9412833669fdc800000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1d9d4d714865f500000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x4ef8ce836bba8c0000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xb481d807d1aa68000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x16903b00fa354d000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x281cdaac677b3400000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x402e2aad725eb80000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x5d5a6c9f31fe24000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x7c7890d442a83000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9931ed540345280000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaf147cf24ce150000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d00000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xafc441338061b8000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9c3cabbc0056e000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x839168328705c80000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x694120286c04a0000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x50319e98b3d2c400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x3a52a1e36b82020;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x289286e0fce002;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1b0c59eb53400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x114f95b55400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaa7210d200;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x650139600;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x39b78e80;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1fd8080;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x10fbc0;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x8c40;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x462;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x22;

        return res / 0xde1bc4d19efcac82445da75b00000000;
    }
}

pragma solidity ^0.4.11;
import './SafeMath.sol';
import './IBancorFormula.sol';

/*
    Open issues:
    - The formula is not yet super accurate, especially for very small/very high ratios
    - Possibly support dynamic precision in the future
*/

contract BancorFormula is IBancorFormula, SafeMath {
    uint8 constant PRECISION = 32;  // fractional bits

    string public version = '0.1';

    function BancorFormula() {
    }

    /**
        @dev given a token supply, reserve, CRR and a deposit amount (in the reserve token), calculates the return for a given change (in the main token)

        Formula:
        Return = _supply * ((1 + _depositAmount / _reserveBalance) ^ (_reserveRatio / 100) - 1)

        @param _supply             token total supply
        @param _reserveBalance     total reserve
        @param _reserveRatio       constant reserve ratio, 1-100
        @param _depositAmount      deposit amount, in reserve token

        @return purchase return amount
    */
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _depositAmount) public constant returns (uint256) {
        // validate input
        require(_supply != 0 && _reserveBalance != 0 && _reserveRatio > 0 && _reserveRatio <= 100);

        // special case for 0 deposit amount
        if (_depositAmount == 0)
            return 0;

        uint256 baseN = safeAdd(_depositAmount, _reserveBalance);
        uint256 temp;

        // special case if the CRR = 100
        if (_reserveRatio == 100) {
            temp = safeMul(_supply, baseN) / _reserveBalance;
            return safeSub(temp, _supply);
        }

        var resD = uint256(1) << PRECISION;
        var resN = power(baseN, _reserveBalance, _reserveRatio, 100);
        temp = safeMul(_supply, resN) / resD;
        var result = safeSub(temp, _supply);

        //From the result, we deduct the minimal increment, which is a
        // function of S and precision.
        return safeSub(result, _supply/0x100000000);
     }

    /**
        @dev given a token supply, reserve, CRR and a sell amount (in the main token), calculates the return for a given change (in the reserve token)

        Formula:
        Return = _reserveBalance * (1 - (1 - _sellAmount / _supply) ^ (1 / (_reserveRatio / 100)))

        @param _supply             token total supply
        @param _reserveBalance     total reserve
        @param _reserveRatio       constant reserve ratio, 1-100
        @param _sellAmount         sell amount, in the token itself

        @return sale return amount
    */
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _sellAmount) public constant returns (uint256) {
        // validate input
        require(_supply != 0 && _reserveBalance != 0 && _reserveRatio > 0 && _reserveRatio <= 100 && _sellAmount <= _supply);

        // special case for 0 sell amount
        if (_sellAmount == 0)
            return 0;

        uint256 baseN = safeSub(_supply, _sellAmount);
        uint256 temp1;
        uint256 temp2;

        // special case if the CRR = 100
        if (_reserveRatio == 100) {
            temp1 = safeMul(_reserveBalance, _supply);
            temp2 = safeMul(_reserveBalance, baseN);
            return safeSub(temp1, temp2) / _supply;
        }

        // special case for selling the entire supply
        if (_sellAmount == _supply)
            return _reserveBalance;

        var resD = uint256(1) << PRECISION;
        var resN = powerRoundDown(_supply, baseN, 100, _reserveRatio);
        temp1 = safeMul(_reserveBalance, resN);
        temp2 = safeMul(_reserveBalance, resD);

        var result = safeSub(temp1, temp2) / resN;
        //From the result, we deduct the minimal increment, which is a
        // function of R and precision.
        return safeSub(result, _reserveBalance/0x100000000);
    }

    /**
        @dev Calculate (_baseN / _baseD) ^ (_expN / _expD)
        Returns result upshifted by PRECISION

        This method is overflow-safe
    */
    function power(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) constant returns (uint256 resN) {
        uint256 logbase = ln(_baseN, _baseD);
        // Not using safeDiv here, since safeDiv protects against
        // precision loss. It's unavoidable, however
        // Both `ln` and `fixedExp` are overflow-safe.
        resN = fixedExp(safeMul(logbase, _expN) / _expD);

        return resN;
	}
    /**
        @dev Calculate (_baseN / _baseD) ^ (_expN / _expD)
        This mehthod is skewed to make the precision loss error decrease the result
        Returns result upshifted by PRECISION

        This method is overflow-safe
    */
    function powerRoundDown(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) constant returns (uint256 resN) {

        // In `ln`, the log of numerator and denominator are subtracted:
        // log(n)-log(d) . To ensure that the precision loss is in the right
        // direction, we subtract one unit
        // Reasoning:
        //      floor(log(d)) +1 == ceil(log(d))
        uint256 logbase = ln(_baseN, _baseD);
        if (logbase > 1)
            logbase -= 1;

        // Not using safeDiv here, since safeDiv protects against
        // precision loss. It's unavoidable, however
        // Both `ln` and `fixedExp` are overflow-safe.
        resN = fixedExp(safeMul(logbase, _expN) / _expD);
        return resN;
    }

    /**
        input range:
            - numerator: [1, uint256_max >> PRECISION]
            - denominator: [1, uint256_max >> PRECISION]
        output range:
            [0, 0x9b43d4f8d6]

        This method asserts outside of bounds

    */
    function ln(uint256 _numerator, uint256 _denominator) constant returns (uint256) {
        // denominator > numerator: less than one yields negative values. Unsupported
        assert(_denominator <= _numerator);

        // log(1) is the lowest we can go
        assert(_denominator != 0 && _numerator != 0);

        // Upper 32 bits are scaled off by PRECISION
        assert(_numerator & 0xffffffff00000000000000000000000000000000000000000000000000000000 == 0);
        assert(_denominator & 0xffffffff00000000000000000000000000000000000000000000000000000000 == 0);

        return fixedLoge(_numerator << PRECISION) - fixedLoge(_denominator << PRECISION);
    }

    /**
        input range:
            [0x100000000,uint256_max]
        output range:
            [0, 0x9b43d4f8d6]

        This method asserts outside of bounds

    */
    function fixedLoge(uint256 _x) constant returns (uint256 logE) {
        /*
        Since `fixedLog2` output range is max `0xdfffffffff`
        (40 bits, or 5 bytes), we can use a very large approximation
        for `ln(2)`. This one is used since it's the max accuracy
        of Python `ln(2)`

        0xb17217f7d1cf78 = ln(2) * (1 << 56)

        */
        //Cannot represent negative numbers (below 1)
        assert(_x >= 0x100000000);

        uint256 log2 = fixedLog2(_x);
        logE = (log2 * 0xb17217f7d1cf78) >> 56;
    }

    /**
        Returns log2(x >> 32) << 32
        So x is assumed to be already upshifted 32 bits, and
        the result is also upshifted 32 bits.

        input-range :
            [0x100000000,uint256_max]
        output-range:
            [0,0xdfffffffff]

        This method asserts outside of bounds

    */
    function fixedLog2(uint256 _x) constant returns (uint256) {
        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 fixedTwo = uint256(2) << PRECISION;

        // Numbers below 1 are negative.
        assert( _x >= fixedOne);
        //if (_x < fixedTwo) {
        //    if (_x >= fixedOne){
        //        return 0;
        //    }
        //    assert(false);
        //}

        uint256 lo = 0;
        uint256 hi = 0;

        while (_x < fixedOne) {
            _x <<= 1;
            lo += fixedOne;
        }

        while (_x >= fixedTwo) {
            _x >>= 1;
            hi += fixedOne;
        }

        for (uint8 i = 0; i < PRECISION; ++i) {
            _x = (_x * _x) >> PRECISION;
            if (_x >= fixedTwo) {
                _x >>= 1;
                hi += uint256(1) << (PRECISION - 1 - i);
            }
        }
        if (lo > hi) {
            //Should never happen, due to the check above
            // but this is a cheap extra check in case the
            // implementation changes over time
            assert(false);
        }

        return hi - lo;
    }

    /**
        fixedExp is a 'protected' version of `fixedExpUnsafe`, which
        asserts instead of overflows
    */
    function fixedExp(uint256 _x) constant returns (uint256) {
        assert(_x <= 0x386bfdba29);
        return fixedExpUnsafe(_x);
    }

    /**
        fixedExp
        Calculates e^x according to maclauren summation:

        e^x = 1+x+x^2/2!...+x^n/n!

        and returns e^(x>>32) << 32, that is, upshifted for accuracy

        Input range:
            - Function ok at    <= 242329958953
            - Function fails at >= 242329958954

        This method is is visible for testcases, but not meant for direct use.
    */
    function fixedExpUnsafe(uint256 _x) constant returns (uint256) {
        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 xi = fixedOne;
        uint256 res = 0xde1bc4d19efcac82445da75b00000000 * xi;

        xi = (xi * _x) >> PRECISION;
        res += xi * 0xde1bc4d19efcb0000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x6f0de268cf7e58000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x2504a0cd9a7f72000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9412833669fdc800000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1d9d4d714865f500000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x4ef8ce836bba8c0000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xb481d807d1aa68000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x16903b00fa354d000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x281cdaac677b3400000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x402e2aad725eb80000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x5d5a6c9f31fe24000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x7c7890d442a83000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9931ed540345280000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaf147cf24ce150000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d00000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xafc441338061b8000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9c3cabbc0056e000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x839168328705c80000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x694120286c04a0000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x50319e98b3d2c400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x3a52a1e36b82020;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x289286e0fce002;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1b0c59eb53400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x114f95b55400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaa7210d200;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x650139600;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x39b78e80;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1fd8080;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x10fbc0;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x8c40;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x462;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x22;

        return res / 0xde1bc4d19efcac82445da75b00000000;
    }
}


Fixed error: Bishop only diagonal, Rook only non-diagonal moves

was switched before

/**
 * Chess contract
 * Stores any amount of games with two players and current state.
 * State encoding:
 *    positive numbers for white, negative numbers for black
 *    for details, see
 *    https://github.com/ise-ethereum/on-chain-chess/wiki/Chess-board-representation
 */

 contract Chess {
    bytes constant defaultState = '\x04\x06\x05\x03\x02\x05\x06\x04\x08\x08\x08\x0c\x08\x08\x08\x08\x07\x07\x07\x07\x07\x07\x07\x07\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x09\x09\x09\x09\x09\x09\x09\x09\x08\x08\x08\x08\x08\x08\x08\x08\x0c\x0a\x0b\x0d\x0e\x0b\x0a\x0c\x08\x08\x08\x7c\x08\x08\x08\x08';

    struct Game {
        address player1;
        address player2;
        string player1Alias;
        string player2Alias;
        address nextPlayer;
        address playerWhite; // Player that is white in this game
        address winner;
        int8[128] state;
    }

    mapping (bytes32 => Game) public games;
    mapping (address => mapping (int => bytes32)) public gamesOfPlayers;
    mapping (address => int) public numberGamesOfPlayers;

    // stack of open game ids
    mapping (bytes32 => bytes32) public openGameIds;
    bytes32 public head;

    /* Flags needed for validation
     * Usage e.g. Flags(Flag.FLAG_NAME)
     * Directions(Direction.UP)
     */
    enum Player { WHITE, BLACK }
    enum Direction { UP, UP_RIGHT, RIGHT, DOWN_RIGHT, DOWN, DOWN_LEFT, LEFT, UP_LEFT }
    bytes constant c_Directions = "\x30\x31\x41\x51\x50\x4f\x3f\x2f";
    enum Piece { BLACK_KING, BLACK_QUEEN, BLACK_ROOK, BLACK_BISHOP, BLACK_KNIGHT, BLACK_PAWN, EMPTY, WHITE_PAWN, WHITE_KNIGHT, WHITE_BISHOP, WHITE_ROOK, WHITE_QUEEN, WHITE_KING }
    enum Flag { WHITE_KING_POS, BLACK_KING_POS, CURRENT_PLAYER, WHITE_LEFT_CASTLING, WHITE_RIGHT_CASTLING, BLACK_LEFT_CASTLING, BLACK_RIGHT_CASTLING, BLACK_EN_PASSANT, WHITE_EN_PASSANT}
    bytes constant c_Flags = "\x7b\x0b\x38\x4e\x4f\x3e\x3f\x3d\x4d\x3c\x4c";
    function Flags(Flag i) internal returns (uint) {
       return uint(c_Flags[uint(i)]);
    }
    function Pieces(Piece i) internal returns (int8) {
        return -6 + int8(uint(i));
    }
    function Directions(Direction i) internal returns (int8) {
        return -64 + int8(c_Directions[uint(i)]);
    }
    function Players(Player p) internal returns (int8) {
        if (p == Player.WHITE) {
            return 1;
        }
        return -1;
    }

    bytes constant knightMoves = '\x1f\x21\x2e\x32\x4e\x52\x5f\x61';

    function Chess() {
        head = 'end';
    }

    event GameInitialized(bytes32 indexed gameId, address indexed player1, string player1Alias, address playerWhite);
    event GameJoined(bytes32 indexed gameId, address indexed player1, string player1Alias, address indexed player2, string player2Alias, address playerWhite);
    event GameStateChanged(bytes32 indexed gameId, int8[128] state);
    event Move(bytes32 indexed gameId, address indexed player, uint256 fromIndex, uint256 toIndex);
    event GameEnded(bytes32 indexed gameId, address indexed winner);

    /**
     * Convenience function to set a flag
     * Usage: setFlag(gameId, Flag.BLACK_KING_POS, 4);
     */
    function setFlag(bytes32 gameId, Flag flag, int value) internal {
        games[gameId].state[Flags(flag)] = int8(value);
    }

    /**
     * Convenience function to set a flag
     * Usage: getFlag(gameId, Flag.BLACK_KING_POS);
     */
    function getFlag(bytes32 gameId, Flag flag) internal returns (int8) {
        return games[gameId].state[Flags(flag)];
    }

    /**
     * Initialize a new game
     * string player1Alias: Alias of the player creating the game
     * bool playAsWhite: Pass true or false depending on if the creator will play as white
     */
    function initGame(string player1Alias, bool playAsWhite) public {
        // Generate game id based on player's addresses and current block number
        bytes32 gameId = sha3(msg.sender, block.number);

        // Initialize participants
        games[gameId].player1 = msg.sender;
        games[gameId].player1Alias = player1Alias;

        // Initialize state
        for (uint i = 0; i < 128; i++) {
            // Read defaultState bytes string, which is offset by 8 to be > 0
            games[gameId].state[i] = int8(defaultState[i]) - 8;
        }

        if (playAsWhite) {
            // Player 1 will play as white
            games[gameId].playerWhite = msg.sender;

            // Game starts with White, so here player 1
            games[gameId].nextPlayer = games[gameId].player1;
        }

        // Add game to gamesOfPlayers
        gamesOfPlayers[msg.sender][numberGamesOfPlayers[msg.sender]] = gameId;
        numberGamesOfPlayers[msg.sender]++;

        // Add to openGameIds
        openGameIds[gameId] = head;
        head = gameId;

        // Sent notification events
        GameInitialized(gameId, games[gameId].player1, player1Alias, games[gameId].playerWhite);
        GameStateChanged(gameId, games[gameId].state);
    }

    /**
     * Join an initialized game
     * bytes32 gameId: ID of the game to join
     * string player2Alias: Alias of the player that is joining
     */
    function joinGame(bytes32 gameId, string player2Alias) public {
        // Check that this game does not have a second player yet
        if (games[gameId].player2 != 0) {
            throw;
        }

        games[gameId].player2 = msg.sender;
        games[gameId].player2Alias = player2Alias;

        // If the other player isn't white, player2 will play as white
        if (games[gameId].playerWhite == 0) {
            games[gameId].playerWhite = msg.sender;
            // Game starts with White, so here player2
            games[gameId].nextPlayer = games[gameId].player2;
        }

        // Add game to gamesOfPlayers
        gamesOfPlayers[msg.sender][numberGamesOfPlayers[msg.sender]] = gameId;
        numberGamesOfPlayers[msg.sender]++;

        // Remove from openGameIds
        if (head == gameId) {
            head = openGameIds[head];
            openGameIds[gameId] = 0;
        } else {
            for (var g = head; g != 'end' && openGameIds[g] != 'end'; g = openGameIds[g]) {
                if (openGameIds[g] == gameId) {
                    openGameIds[g] = openGameIds[gameId];
                    openGameIds[gameId] = 0;
                    break;
                }
            }
        }

        GameJoined(gameId, games[gameId].player1, games[gameId].player1Alias, games[gameId].player2, player2Alias, games[gameId].playerWhite);
    }

    /* validates a move and executes it */
    function move(bytes32 gameId, uint256 fromIndex, uint256 toIndex) public {
        // Check that it is this player's turn
        if (games[gameId].nextPlayer != msg.sender) {
            throw;
        }

        int8 currentPlayerColor;
        if (msg.sender == games[gameId].playerWhite) {
            currentPlayerColor = Players(Player.WHITE);
        } else {
            currentPlayerColor = Players(Player.BLACK);
        }

        int8 fromFigure = games[gameId].state[fromIndex];
        int8 toFigure = games[gameId].state[toIndex];

        // Simple sanity checks
        sanityCheck(fromIndex, toIndex, fromFigure, toFigure, currentPlayerColor);

        // Check if move is technically possible
        validateMove(gameId, fromIndex, toIndex, fromFigure, toFigure, currentPlayerColor);

        // For all pieces except knight, check if way is free
        // In case of king, it will check that he is not in check on any of the fields
        if (abs(fromFigure) != uint(Pieces(Piece.BLACK_KNIGHT))) {
            bool checkForCheck = abs(fromFigure) == uint(Pieces(Piece.BLACK_KING));
            checkWayFree(gameId, fromIndex, toIndex, currentPlayerColor, checkForCheck);
        }

        //makeTemporaryMove
        makeTemporaryMove(gameId, fromIndex, toIndex, fromFigure, toFigure);

        //isLegal

        //testIfCheck

        // Update state
        games[gameId].state[toIndex] = games[gameId].state[fromIndex];
        games[gameId].state[fromIndex] = 0;

        // Set nextPlayer
        if (msg.sender == games[gameId].player1) {
            games[gameId].nextPlayer = games[gameId].player2;
        } else {
            games[gameId].nextPlayer = games[gameId].player1;
        }

        Move(gameId, msg.sender, fromIndex, toIndex);
        GameStateChanged(gameId, games[gameId].state);
    }

    function sanityCheck(uint256 fromIndex, uint256 toIndex, int8 fromFigure, int8 toFigure, int8 currentPlayerColor) {
        // check if the move actually fits the data structure
        if (((toIndex & 0x88) != 0) && ((fromIndex & 0x88) != 0)) {
            throw;
        }

        // check if the move tries to move a figure onto it self
        if (fromIndex == toIndex) {
            throw;
        }

        // check if the toIndex is empty (= is 0) or contains an enemy figure ("positive" * "negative" = "negative")
        // --> this only allows captures (negative results)  or moves to empty fields ( = 0)
        // also check if there is a figure at fromIndex to move (fromFigure != 0)
        if (fromFigure * toFigure > 0) {
            throw;
        }

        // check if mover of the figure is the owner of the figure
        // todo: fix color to enum
        if (currentPlayerColor * fromFigure > 0) {
            throw;
        }
    }

    /**
     * Validates if a move is technically (not legally) possible,
     * i.e. if piece is capable to move this way
     */
    function validateMove(bytes32 gameId, uint256 fromIndex, uint256 toIndex, int8 fromFigure, int8 toFigure, int8 movingPlayerColor) {
        int8 direction = getDirection(fromIndex, toIndex);
        bool isDiagonal = !(abs(direction) == 16 || abs(direction) == 1);

        // Kings
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_KING))) {
            // Normal move
            if (int(fromIndex) + direction == int(toIndex)) {
                return;
            }
            // Castling
            if (checkForCheck(gameId, fromIndex, movingPlayerColor)) {
                // Cannot move if already in check
                throw;
            }
            if (fromFigure == Pieces(Piece.BLACK_KING)) {
                if (4 == fromIndex && toFigure == 0) {
                    if (toIndex == 2 && getFlag(gameId, Flag.BLACK_LEFT_CASTLING) >= 0) {
                        return;
                    }
                    if (toIndex == 6 && getFlag(gameId, Flag.BLACK_RIGHT_CASTLING) >= 0) {
                        return;
                    }
                }
            }
            if (fromFigure == Pieces(Piece.WHITE_KING)) {
                if (116 == fromIndex && toFigure == 0) {
                    if (toIndex == 114 && getFlag(gameId, Flag.WHITE_LEFT_CASTLING) >= 0) {
                        return;
                    }
                    if (toIndex == 118 && getFlag(gameId, Flag.WHITE_RIGHT_CASTLING) >= 0) {
                        return;
                    }
                }
            }

            throw;
        }

        // Bishops, Queens, Rooks
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_BISHOP)) ||
            abs(fromFigure) == uint(Pieces(Piece.BLACK_QUEEN)) ||
            abs(fromFigure) == uint(Pieces(Piece.BLACK_ROOK))) {

            if (isDiagonal && abs(fromFigure) == uint(Pieces(Piece.BLACK_BISHOP)) ||
                !isDiagonal && abs(fromFigure) == uint(Pieces(Piece.BLACK_ROOK))) {
                return;
            }

            // Traverse all fields in direction
            int temp = int(fromIndex);
            while (temp & 0x88 != 0) {
                if (uint(temp) == toIndex) {
                    return;
                }
                temp += direction;
            }

            throw;
        }

        // Pawns
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_PAWN))) {
            // Black can only move in positive, White negative direction
            if (fromFigure == Pieces(Piece.BLACK_PAWN) && direction < 0 ||
                fromFigure == Pieces(Piece.WHITE_PAWN) && direction > 0) {
                throw;
            }
            // Forward move
            if (!isDiagonal) {
                if (abs(direction) < 2) {
                    throw;
                }
                // simple move
                if (int(fromIndex) + direction == int(toIndex)) {
                    return;
                }
                // double move
                if (int(fromIndex) + direction + direction == int(toIndex)) {
                    // Can only do double move starting form specific ranks
                    int rank = int(fromIndex/16);
                    if (1 == rank || 6 == rank) {
                        return;
                    }
                }
                throw;
            }
            // diagonal move
            if (int(fromIndex) + direction == int(toIndex)) {
                // if empty, the en passant flag needs to be set
                if (toFigure * fromFigure == 0) {
                    if (fromFigure == Pieces(Piece.BLACK_PAWN) &&
                        getFlag(gameId, Flag.WHITE_EN_PASSANT) == int(toIndex) ||
                        fromFigure == Pieces(Piece.WHITE_PAWN) &&
                        getFlag(gameId, Flag.BLACK_EN_PASSANT) == int(toIndex)) {
                        return;
                    }
                }
                // If not empty
                return;
            }

            throw;
        }

        // Knights
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_KNIGHT))) {
            for (uint i; i < 8; i++) {
                if (int(fromIndex) + int(knightMoves[i]) - 64 == int(toIndex)) {
                    return;
                }
            }
            throw;
        }

        throw;
    }

    /**
     * Checks if the way between fromIndex and toIndex is unblocked
     */
    function checkWayFree(bytes32 gameId, uint256 fromIndex, uint256 toIndex, int8 currentPlayerColor, bool shouldCheckForCheck) {
        int8 direction = getDirection(fromIndex, toIndex);
        int currentIndex = int(fromIndex) + direction;

        // as long as we do not reach the desired position
        while (int(toIndex) != currentIndex) {
            // we reached the end of the field
            if (currentIndex & 0x88 != 0) {
                throw;
            }
            // the path is blocked
            if (games[gameId].state[uint(currentIndex)] != 0) {
                throw;
            }
            // Check for check in case of kind
            if (shouldCheckForCheck && checkForCheck(gameId, uint(currentIndex), currentPlayerColor)) {
                throw;
            }
            currentIndex = currentIndex + direction;
        }
        return;
    }

    function checkForCheck(bytes32 gameId, uint256 kingAtIndex, int8 currentPlayerColor) returns (bool) {
        // TODO
        return true;
    }

    function getDirection(uint256 fromIndex, uint256 toIndex) returns (int8) {
        // check if the figure is moved up or left of its origin
        bool isAboveLeft = fromIndex > toIndex;

        // check if the figure is moved in an horizontal plane
        // this code works because there is an eight square difference between the horizontal panes (the offboard)
        bool isSameHorizontal = (abs(int256(fromIndex) - int256(toIndex)) < (8));

        // check if the figure is moved in a vertical line
        bool isSameVertical = (fromIndex%8 == toIndex%8);

        // check if the figure is moved to the left of its origin
        bool isLeftSide = (fromIndex%8 > toIndex%8);

        /*Check directions*/
        if (isAboveLeft){
            if (isSameVertical){
                return Directions(Direction.UP);
            }
            if (isSameHorizontal){
                return Directions(Direction.LEFT);
            }
            if (isLeftSide){
                return Directions(Direction.UP_LEFT);
            } else {
                return Directions(Direction.UP_RIGHT);
            }
        } else {
            if (isSameVertical){
                return Directions(Direction.DOWN);
            }
            if (isSameHorizontal){
                return Directions(Direction.RIGHT);
            }
            if (isLeftSide){
                return Directions(Direction.DOWN_LEFT);
            } else{
                return Directions(Direction.DOWN_RIGHT);
            }
        }
    }

    function makeTemporaryMove(bytes32 gameId, uint256 fromIndex, uint256 toIndex, int8 fromFigure, int8 toFigure){
        setFlag(gameId, Flag.WHITE_EN_PASSANT, -1);
        setFlag(gameId, Flag.WHITE_EN_PASSANT, -1);

        // <---- Special Moves ---->

        // castling
        // it already passed valid we just need to move the rook

        // Black
        if (fromFigure == Pieces(Piece.BLACK_KING)){
            setFlag(gameId, Flag.BLACK_KING_POS, int8(toIndex));
            if ((fromIndex == 4)&&(toIndex == 1)){
                games[gameId].state[0] = 0;
                games[gameId].state[2] = Pieces(Piece.BLACK_ROOK);
            }
            if ((fromIndex == 4)&&(toIndex == 6)){
                games[gameId].state[7] = 0;
                games[gameId].state[5] = Pieces(Piece.BLACK_ROOK);
            }

        }
        // White
        if (fromFigure == Pieces(Piece.WHITE_KING)){
            setFlag(gameId, Flag.WHITE_KING_POS, int8(toIndex));
            if ((fromIndex == 116)&&(toIndex == 112)){
                games[gameId].state[112] = 0;
                games[gameId].state[114] = Pieces(Piece.BLACK_ROOK);
            }
            if ((fromIndex == 116)&&(toIndex == 118)){
                games[gameId].state[118] = 0;
                games[gameId].state[117] = Pieces(Piece.BLACK_ROOK);
            }

        }

        //Remove Castling Flag

        // Black
        if (fromFigure == Pieces(Piece.BLACK_KING)){
            if (fromIndex == 4){
                setFlag(gameId, Flag.BLACK_LEFT_CASTLING, -1);
                setFlag(gameId, Flag.BLACK_RIGHT_CASTLING, -1);
            }
        }
        if (fromFigure == Pieces(Piece.BLACK_ROOK)){
            if (fromIndex == 0){
                setFlag(gameId, Flag.BLACK_LEFT_CASTLING, -1);
            }
            if (fromIndex == 7){
                setFlag(gameId, Flag.BLACK_RIGHT_CASTLING, -1);
            }
        }

        // White
        if (fromFigure == Pieces(Piece.WHITE_KING)){
            if (fromIndex == 116){
                setFlag(gameId, Flag.WHITE_LEFT_CASTLING, -1);
                setFlag(gameId, Flag.WHITE_RIGHT_CASTLING, -1);
            }
        }
        if (fromFigure == Pieces(Piece.WHITE_ROOK)){
            if (fromIndex == 112){
                setFlag(gameId, Flag.WHITE_LEFT_CASTLING, -1);
            }
            if (fromIndex == 119){
                setFlag(gameId, Flag.WHITE_RIGHT_CASTLING, -1);
            }
        }
        // En Passant

        // Double Step

        // <---- Normal Moves --->

        games[gameId].state[toIndex] = games[gameId].state[fromIndex];
        games[gameId].state[fromIndex] = 0;

    }

    function isLegal() {

    }

    function testIfCheck() {

    }

    function surrender(bytes32 gameId) public {
        if (games[gameId].winner != 0) {
            // Game already ended
            throw;
        }
        if (games[gameId].player1 == msg.sender) {
            // Player 1 surrendered, player 2 won
            games[gameId].winner = games[gameId].player2;
        } else if(games[gameId].player2 == msg.sender) {
            // Player 2 surrendered, player 1 won
            games[gameId].winner = games[gameId].player1;
        } else {
            // Sender is not a participant of this game
            throw;
        }

        GameEnded(gameId, games[gameId].winner);
    }

    function getGameId(address player, int index) constant returns (bytes32) {
        return gamesOfPlayers[player][index];
    }

    /*------------------------HELPER FUNCTIONS------------------------*/

    // This returns the absolute value of an integer
    function abs(int256 value) returns (uint256){
        if (value>=0) return uint256(value);
        else return uint256(-1*value);
    }

    function is_diagonal(Direction dir) internal returns (bool){
      if(abs(Directions(dir)) == 16)
        return false;
      if(abs(Directions(dir)) == 1)
        return false;
      return true;
    }

    /* This unnamed function is called whenever someone tries to send ether to it */
    function () {
        throw;     // Prevents accidental sending of ether
    }
}

/**
 * Chess contract
 * Stores any amount of games with two players and current state.
 * State encoding:
 *    positive numbers for white, negative numbers for black
 *    for details, see
 *    https://github.com/ise-ethereum/on-chain-chess/wiki/Chess-board-representation
 */

 contract Chess {
    bytes constant defaultState = '\x04\x06\x05\x03\x02\x05\x06\x04\x08\x08\x08\x0c\x08\x08\x08\x08\x07\x07\x07\x07\x07\x07\x07\x07\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x09\x09\x09\x09\x09\x09\x09\x09\x08\x08\x08\x08\x08\x08\x08\x08\x0c\x0a\x0b\x0d\x0e\x0b\x0a\x0c\x08\x08\x08\x7c\x08\x08\x08\x08';

    struct Game {
        address player1;
        address player2;
        string player1Alias;
        string player2Alias;
        address nextPlayer;
        address playerWhite; // Player that is white in this game
        address winner;
        int8[128] state;
    }

    mapping (bytes32 => Game) public games;
    mapping (address => mapping (int => bytes32)) public gamesOfPlayers;
    mapping (address => int) public numberGamesOfPlayers;

    // stack of open game ids
    mapping (bytes32 => bytes32) public openGameIds;
    bytes32 public head;

    /* Flags needed for validation
     * Usage e.g. Flags(Flag.FLAG_NAME)
     * Directions(Direction.UP)
     */
    enum Player { WHITE, BLACK }
    enum Direction { UP, UP_RIGHT, RIGHT, DOWN_RIGHT, DOWN, DOWN_LEFT, LEFT, UP_LEFT }
    bytes constant c_Directions = "\x30\x31\x41\x51\x50\x4f\x3f\x2f";
    enum Piece { BLACK_KING, BLACK_QUEEN, BLACK_ROOK, BLACK_BISHOP, BLACK_KNIGHT, BLACK_PAWN, EMPTY, WHITE_PAWN, WHITE_KNIGHT, WHITE_BISHOP, WHITE_ROOK, WHITE_QUEEN, WHITE_KING }
    enum Flag { WHITE_KING_POS, BLACK_KING_POS, CURRENT_PLAYER, WHITE_LEFT_CASTLING, WHITE_RIGHT_CASTLING, BLACK_LEFT_CASTLING, BLACK_RIGHT_CASTLING, BLACK_EN_PASSANT, WHITE_EN_PASSANT}
    bytes constant c_Flags = "\x7b\x0b\x38\x4e\x4f\x3e\x3f\x3d\x4d\x3c\x4c";
    function Flags(Flag i) internal returns (uint) {
       return uint(c_Flags[uint(i)]);
    }
    function Pieces(Piece i) internal returns (int8) {
        return -6 + int8(uint(i));
    }
    function Directions(Direction i) internal returns (int8) {
        return -64 + int8(c_Directions[uint(i)]);
    }
    function Players(Player p) internal returns (int8) {
        if (p == Player.WHITE) {
            return 1;
        }
        return -1;
    }

    bytes constant knightMoves = '\x1f\x21\x2e\x32\x4e\x52\x5f\x61';

    function Chess() {
        head = 'end';
    }

    event GameInitialized(bytes32 indexed gameId, address indexed player1, string player1Alias, address playerWhite);
    event GameJoined(bytes32 indexed gameId, address indexed player1, string player1Alias, address indexed player2, string player2Alias, address playerWhite);
    event GameStateChanged(bytes32 indexed gameId, int8[128] state);
    event Move(bytes32 indexed gameId, address indexed player, uint256 fromIndex, uint256 toIndex);
    event GameEnded(bytes32 indexed gameId, address indexed winner);

    /**
     * Convenience function to set a flag
     * Usage: setFlag(gameId, Flag.BLACK_KING_POS, 4);
     */
    function setFlag(bytes32 gameId, Flag flag, int value) internal {
        games[gameId].state[Flags(flag)] = int8(value);
    }

    /**
     * Convenience function to set a flag
     * Usage: getFlag(gameId, Flag.BLACK_KING_POS);
     */
    function getFlag(bytes32 gameId, Flag flag) internal returns (int8) {
        return games[gameId].state[Flags(flag)];
    }

    /**
     * Initialize a new game
     * string player1Alias: Alias of the player creating the game
     * bool playAsWhite: Pass true or false depending on if the creator will play as white
     */
    function initGame(string player1Alias, bool playAsWhite) public {
        // Generate game id based on player's addresses and current block number
        bytes32 gameId = sha3(msg.sender, block.number);

        // Initialize participants
        games[gameId].player1 = msg.sender;
        games[gameId].player1Alias = player1Alias;

        // Initialize state
        for (uint i = 0; i < 128; i++) {
            // Read defaultState bytes string, which is offset by 8 to be > 0
            games[gameId].state[i] = int8(defaultState[i]) - 8;
        }

        if (playAsWhite) {
            // Player 1 will play as white
            games[gameId].playerWhite = msg.sender;

            // Game starts with White, so here player 1
            games[gameId].nextPlayer = games[gameId].player1;
        }

        // Add game to gamesOfPlayers
        gamesOfPlayers[msg.sender][numberGamesOfPlayers[msg.sender]] = gameId;
        numberGamesOfPlayers[msg.sender]++;

        // Add to openGameIds
        openGameIds[gameId] = head;
        head = gameId;

        // Sent notification events
        GameInitialized(gameId, games[gameId].player1, player1Alias, games[gameId].playerWhite);
        GameStateChanged(gameId, games[gameId].state);
    }

    /**
     * Join an initialized game
     * bytes32 gameId: ID of the game to join
     * string player2Alias: Alias of the player that is joining
     */
    function joinGame(bytes32 gameId, string player2Alias) public {
        // Check that this game does not have a second player yet
        if (games[gameId].player2 != 0) {
            throw;
        }

        games[gameId].player2 = msg.sender;
        games[gameId].player2Alias = player2Alias;

        // If the other player isn't white, player2 will play as white
        if (games[gameId].playerWhite == 0) {
            games[gameId].playerWhite = msg.sender;
            // Game starts with White, so here player2
            games[gameId].nextPlayer = games[gameId].player2;
        }

        // Add game to gamesOfPlayers
        gamesOfPlayers[msg.sender][numberGamesOfPlayers[msg.sender]] = gameId;
        numberGamesOfPlayers[msg.sender]++;

        // Remove from openGameIds
        if (head == gameId) {
            head = openGameIds[head];
            openGameIds[gameId] = 0;
        } else {
            for (var g = head; g != 'end' && openGameIds[g] != 'end'; g = openGameIds[g]) {
                if (openGameIds[g] == gameId) {
                    openGameIds[g] = openGameIds[gameId];
                    openGameIds[gameId] = 0;
                    break;
                }
            }
        }

        GameJoined(gameId, games[gameId].player1, games[gameId].player1Alias, games[gameId].player2, player2Alias, games[gameId].playerWhite);
    }

    /* validates a move and executes it */
    function move(bytes32 gameId, uint256 fromIndex, uint256 toIndex) public {
        // Check that it is this player's turn
        if (games[gameId].nextPlayer != msg.sender) {
            throw;
        }

        int8 currentPlayerColor;
        if (msg.sender == games[gameId].playerWhite) {
            currentPlayerColor = Players(Player.WHITE);
        } else {
            currentPlayerColor = Players(Player.BLACK);
        }

        int8 fromFigure = games[gameId].state[fromIndex];
        int8 toFigure = games[gameId].state[toIndex];

        // Simple sanity checks
        sanityCheck(fromIndex, toIndex, fromFigure, toFigure, currentPlayerColor);

        // Check if move is technically possible
        validateMove(gameId, fromIndex, toIndex, fromFigure, toFigure, currentPlayerColor);

        // For all pieces except knight, check if way is free
        // In case of king, it will check that he is not in check on any of the fields
        if (abs(fromFigure) != uint(Pieces(Piece.BLACK_KNIGHT))) {
            bool checkForCheck = abs(fromFigure) == uint(Pieces(Piece.BLACK_KING));
            checkWayFree(gameId, fromIndex, toIndex, currentPlayerColor, checkForCheck);
        }

        //makeTemporaryMove
        makeTemporaryMove(gameId, fromIndex, toIndex, fromFigure, toFigure);

        //isLegal

        //testIfCheck

        // Update state
        games[gameId].state[toIndex] = games[gameId].state[fromIndex];
        games[gameId].state[fromIndex] = 0;

        // Set nextPlayer
        if (msg.sender == games[gameId].player1) {
            games[gameId].nextPlayer = games[gameId].player2;
        } else {
            games[gameId].nextPlayer = games[gameId].player1;
        }

        Move(gameId, msg.sender, fromIndex, toIndex);
        GameStateChanged(gameId, games[gameId].state);
    }

    function sanityCheck(uint256 fromIndex, uint256 toIndex, int8 fromFigure, int8 toFigure, int8 currentPlayerColor) {
        // check if the move actually fits the data structure
        if (((toIndex & 0x88) != 0) && ((fromIndex & 0x88) != 0)) {
            throw;
        }

        // check if the move tries to move a figure onto it self
        if (fromIndex == toIndex) {
            throw;
        }

        // check if the toIndex is empty (= is 0) or contains an enemy figure ("positive" * "negative" = "negative")
        // --> this only allows captures (negative results)  or moves to empty fields ( = 0)
        // also check if there is a figure at fromIndex to move (fromFigure != 0)
        if (fromFigure * toFigure > 0) {
            throw;
        }

        // check if mover of the figure is the owner of the figure
        // todo: fix color to enum
        if (currentPlayerColor * fromFigure > 0) {
            throw;
        }
    }

    /**
     * Validates if a move is technically (not legally) possible,
     * i.e. if piece is capable to move this way
     */
    function validateMove(bytes32 gameId, uint256 fromIndex, uint256 toIndex, int8 fromFigure, int8 toFigure, int8 movingPlayerColor) {
        int8 direction = getDirection(fromIndex, toIndex);
        bool isDiagonal = !(abs(direction) == 16 || abs(direction) == 1);

        // Kings
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_KING))) {
            // Normal move
            if (int(fromIndex) + direction == int(toIndex)) {
                return;
            }
            // Castling
            if (checkForCheck(gameId, fromIndex, movingPlayerColor)) {
                // Cannot move if already in check
                throw;
            }
            if (fromFigure == Pieces(Piece.BLACK_KING)) {
                if (4 == fromIndex && toFigure == 0) {
                    if (toIndex == 2 && getFlag(gameId, Flag.BLACK_LEFT_CASTLING) >= 0) {
                        return;
                    }
                    if (toIndex == 6 && getFlag(gameId, Flag.BLACK_RIGHT_CASTLING) >= 0) {
                        return;
                    }
                }
            }
            if (fromFigure == Pieces(Piece.WHITE_KING)) {
                if (116 == fromIndex && toFigure == 0) {
                    if (toIndex == 114 && getFlag(gameId, Flag.WHITE_LEFT_CASTLING) >= 0) {
                        return;
                    }
                    if (toIndex == 118 && getFlag(gameId, Flag.WHITE_RIGHT_CASTLING) >= 0) {
                        return;
                    }
                }
            }

            throw;
        }

        // Bishops, Queens, Rooks
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_BISHOP)) ||
            abs(fromFigure) == uint(Pieces(Piece.BLACK_QUEEN)) ||
            abs(fromFigure) == uint(Pieces(Piece.BLACK_ROOK))) {

            if (!isDiagonal && abs(fromFigure) == uint(Pieces(Piece.BLACK_BISHOP)) ||
                isDiagonal && abs(fromFigure) == uint(Pieces(Piece.BLACK_ROOK))) {
                return;
            }

            // Traverse all fields in direction
            int temp = int(fromIndex);
            while (temp & 0x88 != 0) {
                if (uint(temp) == toIndex) {
                    return;
                }
                temp += direction;
            }

            throw;
        }

        // Pawns
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_PAWN))) {
            // Black can only move in positive, White negative direction
            if (fromFigure == Pieces(Piece.BLACK_PAWN) && direction < 0 ||
                fromFigure == Pieces(Piece.WHITE_PAWN) && direction > 0) {
                throw;
            }
            // Forward move
            if (!isDiagonal) {
                if (abs(direction) < 2) {
                    throw;
                }
                // simple move
                if (int(fromIndex) + direction == int(toIndex)) {
                    return;
                }
                // double move
                if (int(fromIndex) + direction + direction == int(toIndex)) {
                    // Can only do double move starting form specific ranks
                    int rank = int(fromIndex/16);
                    if (1 == rank || 6 == rank) {
                        return;
                    }
                }
                throw;
            }
            // diagonal move
            if (int(fromIndex) + direction == int(toIndex)) {
                // if empty, the en passant flag needs to be set
                if (toFigure * fromFigure == 0) {
                    if (fromFigure == Pieces(Piece.BLACK_PAWN) &&
                        getFlag(gameId, Flag.WHITE_EN_PASSANT) == int(toIndex) ||
                        fromFigure == Pieces(Piece.WHITE_PAWN) &&
                        getFlag(gameId, Flag.BLACK_EN_PASSANT) == int(toIndex)) {
                        return;
                    }
                }
                // If not empty
                return;
            }

            throw;
        }

        // Knights
        if (abs(fromFigure) == uint(Pieces(Piece.BLACK_KNIGHT))) {
            for (uint i; i < 8; i++) {
                if (int(fromIndex) + int(knightMoves[i]) - 64 == int(toIndex)) {
                    return;
                }
            }
            throw;
        }

        throw;
    }

    /**
     * Checks if the way between fromIndex and toIndex is unblocked
     */
    function checkWayFree(bytes32 gameId, uint256 fromIndex, uint256 toIndex, int8 currentPlayerColor, bool shouldCheckForCheck) {
        int8 direction = getDirection(fromIndex, toIndex);
        int currentIndex = int(fromIndex) + direction;

        // as long as we do not reach the desired position
        while (int(toIndex) != currentIndex) {
            // we reached the end of the field
            if (currentIndex & 0x88 != 0) {
                throw;
            }
            // the path is blocked
            if (games[gameId].state[uint(currentIndex)] != 0) {
                throw;
            }
            // Check for check in case of kind
            if (shouldCheckForCheck && checkForCheck(gameId, uint(currentIndex), currentPlayerColor)) {
                throw;
            }
            currentIndex = currentIndex + direction;
        }
        return;
    }

    function checkForCheck(bytes32 gameId, uint256 kingAtIndex, int8 currentPlayerColor) returns (bool) {
        // TODO
        return true;
    }

    function getDirection(uint256 fromIndex, uint256 toIndex) returns (int8) {
        // check if the figure is moved up or left of its origin
        bool isAboveLeft = fromIndex > toIndex;

        // check if the figure is moved in an horizontal plane
        // this code works because there is an eight square difference between the horizontal panes (the offboard)
        bool isSameHorizontal = (abs(int256(fromIndex) - int256(toIndex)) < (8));

        // check if the figure is moved in a vertical line
        bool isSameVertical = (fromIndex%8 == toIndex%8);

        // check if the figure is moved to the left of its origin
        bool isLeftSide = (fromIndex%8 > toIndex%8);

        /*Check directions*/
        if (isAboveLeft){
            if (isSameVertical){
                return Directions(Direction.UP);
            }
            if (isSameHorizontal){
                return Directions(Direction.LEFT);
            }
            if (isLeftSide){
                return Directions(Direction.UP_LEFT);
            } else {
                return Directions(Direction.UP_RIGHT);
            }
        } else {
            if (isSameVertical){
                return Directions(Direction.DOWN);
            }
            if (isSameHorizontal){
                return Directions(Direction.RIGHT);
            }
            if (isLeftSide){
                return Directions(Direction.DOWN_LEFT);
            } else{
                return Directions(Direction.DOWN_RIGHT);
            }
        }
    }

    function makeTemporaryMove(bytes32 gameId, uint256 fromIndex, uint256 toIndex, int8 fromFigure, int8 toFigure){
        setFlag(gameId, Flag.WHITE_EN_PASSANT, -1);
        setFlag(gameId, Flag.WHITE_EN_PASSANT, -1);

        // <---- Special Moves ---->

        // castling
        // it already passed valid we just need to move the rook

        // Black
        if (fromFigure == Pieces(Piece.BLACK_KING)){
            setFlag(gameId, Flag.BLACK_KING_POS, int8(toIndex));
            if ((fromIndex == 4)&&(toIndex == 1)){
                games[gameId].state[0] = 0;
                games[gameId].state[2] = Pieces(Piece.BLACK_ROOK);
            }
            if ((fromIndex == 4)&&(toIndex == 6)){
                games[gameId].state[7] = 0;
                games[gameId].state[5] = Pieces(Piece.BLACK_ROOK);
            }

        }
        // White
        if (fromFigure == Pieces(Piece.WHITE_KING)){
            setFlag(gameId, Flag.WHITE_KING_POS, int8(toIndex));
            if ((fromIndex == 116)&&(toIndex == 112)){
                games[gameId].state[112] = 0;
                games[gameId].state[114] = Pieces(Piece.BLACK_ROOK);
            }
            if ((fromIndex == 116)&&(toIndex == 118)){
                games[gameId].state[118] = 0;
                games[gameId].state[117] = Pieces(Piece.BLACK_ROOK);
            }

        }

        //Remove Castling Flag

        // Black
        if (fromFigure == Pieces(Piece.BLACK_KING)){
            if (fromIndex == 4){
                setFlag(gameId, Flag.BLACK_LEFT_CASTLING, -1);
                setFlag(gameId, Flag.BLACK_RIGHT_CASTLING, -1);
            }
        }
        if (fromFigure == Pieces(Piece.BLACK_ROOK)){
            if (fromIndex == 0){
                setFlag(gameId, Flag.BLACK_LEFT_CASTLING, -1);
            }
            if (fromIndex == 7){
                setFlag(gameId, Flag.BLACK_RIGHT_CASTLING, -1);
            }
        }

        // White
        if (fromFigure == Pieces(Piece.WHITE_KING)){
            if (fromIndex == 116){
                setFlag(gameId, Flag.WHITE_LEFT_CASTLING, -1);
                setFlag(gameId, Flag.WHITE_RIGHT_CASTLING, -1);
            }
        }
        if (fromFigure == Pieces(Piece.WHITE_ROOK)){
            if (fromIndex == 112){
                setFlag(gameId, Flag.WHITE_LEFT_CASTLING, -1);
            }
            if (fromIndex == 119){
                setFlag(gameId, Flag.WHITE_RIGHT_CASTLING, -1);
            }
        }
        // En Passant

        // Double Step

        // <---- Normal Moves --->

        games[gameId].state[toIndex] = games[gameId].state[fromIndex];
        games[gameId].state[fromIndex] = 0;

    }

    function isLegal() {

    }

    function testIfCheck() {

    }

    function surrender(bytes32 gameId) public {
        if (games[gameId].winner != 0) {
            // Game already ended
            throw;
        }
        if (games[gameId].player1 == msg.sender) {
            // Player 1 surrendered, player 2 won
            games[gameId].winner = games[gameId].player2;
        } else if(games[gameId].player2 == msg.sender) {
            // Player 2 surrendered, player 1 won
            games[gameId].winner = games[gameId].player1;
        } else {
            // Sender is not a participant of this game
            throw;
        }

        GameEnded(gameId, games[gameId].winner);
    }

    function getGameId(address player, int index) constant returns (bytes32) {
        return gamesOfPlayers[player][index];
    }

    /*------------------------HELPER FUNCTIONS------------------------*/

    // This returns the absolute value of an integer
    function abs(int256 value) returns (uint256){
        if (value>=0) return uint256(value);
        else return uint256(-1*value);
    }

    function is_diagonal(Direction dir) internal returns (bool){
      if(abs(Directions(dir)) == 16)
        return false;
      if(abs(Directions(dir)) == 1)
        return false;
      return true;
    }

    /* This unnamed function is called whenever someone tries to send ether to it */
    function () {
        throw;     // Prevents accidental sending of ether
    }
}


Little bug fixes

Little bug fixes


AssertAddress.sol

AssertAddress.sol

pragma solidity >= 0.4.15 < 0.6.0;

library AssertAddress {

    // Constant: ADDRESS_NULL
    // The null address: 0
    address constant ADDRESS_NULL = 0x0000000000000000000000000000000000000000;

    /*
        Event: TestEvent

        Fired when an assertion is made.

        Params:
            result (bool) - Whether or not the assertion holds.
            message (string) - A message to display if the assertion does not hold.
    */
    event TestEvent(bool indexed result, string message);

    // ************************************** address **************************************

    /*
        Function: equal(address)

        Assert that two addresses are equal.

        : A == B

        Params:
            A (address) - The first address.
            B (address) - The second address.
            message (string) - A message that is sent if the assertion fails.

        Returns:
            result (bool) - The result.
    */
    function equal(address a, address b, string memory message) public returns (bool result) {
        result = (a == b);
        _report(result, message);
    }
    /*
        Function: notEqual(address)

        Assert that two addresses are not equal.

        : A != B

        Params:
            A (address) - The first address.
            B (address) - The second address.
            message (string) - A message that is sent if the assertion fails.

        Returns:
            result (bool) - The result.
    */
    function notEqual(address a, address b, string memory message) public returns (bool result) {
        result = (a != b);
         _report(result, message);
    }

    /*
        Function: isZero(address)

        Assert that an address is zero.

        : addr == ADDRESS_NULL

        Params:
            addr (address) - The address.
            message (string) - A message that is sent if the assertion fails.

        Returns:
            result (bool) - The result.
    */
    function isZero(address addr, string memory message) public returns (bool result) {
        result = (addr == ADDRESS_NULL);
        _report(result, message);
    }

    /*
        Function: isNotZero(address)

        Assert that an address is not zero.

        : addr != ADDRESS_NULL

        Params:
            addr (address) - The address.
            message (string) - A message that is sent if the assertion fails.

        Returns:
            result (bool) - The result.
    */
    function isNotZero(address addr, string memory message) public returns (bool result) {
        result = (addr != ADDRESS_NULL);
        _report(result, message);
    }

    /******************************** internal ********************************/

        /*
            Function: _report

            Internal function for triggering <TestEvent>.

            Params:
                result (bool) - The test result (true or false).
                message (string) - The message that is sent if the assertion fails.
        */
    function _report(bool result, string memory message) internal {
        if(result)
            emit TestEvent(true, "");
        else
            emit TestEvent(false, message);
    }
}

error: pathspec 'packages/truffle-core/lib/testing/AssertAddress.sol' did not match any file(s) known to git


Add greaterThanNow to Utils.sol

Add greaterThanNow to Utils.sol

pragma solidity ^0.4.15;

/**
 * @title Utils
 * @dev Utilities & Common Modifiers for ERC23
 * created by IAM <DEV> (Elky Bachtiar)
 * https://www.iamdeveloper.io
 */
contract Utils {

    /**
        constructor
    */
    function Utils() {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != 0x0 && _address != address(0) && _address != 0);
        _;
    }

    // validates multiple addresses - currently only checks that it isn't null
    modifier validAddresses(address _address, address _anotherAddress) {
        require((_address != 0x0         && _address != address(0)        && _address != 0 ) &&
                ( _anotherAddress != 0x0 && _anotherAddress != address(0) && _anotherAddress != 0)
        );
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // validates an uint256 input - currently only checks that it isn't empty
    modifier validInputUint256(uint256 _input) {
        bytes[] memory tempInput = new bytes[](_input);
        require(tempInput[0].length != 0);
        _;
    }

    // validates an bytes input - currently only checks that it isn't empty
    modifier validInputBytes(bytes _input) {
        bytes memory tempInput = bytes(_input);
        require(tempInput.length != 0);
        _;
    }

    // verifies that an amount is greater than zero
    modifier greaterThanNow(uint256 _startTime) {
         require(_startTime >= now);
        _;
    }
}

pragma solidity ^0.4.15;

/**
 * @title Utils
 * @dev Utilities & Common Modifiers for ERC23
 * created by IAM <DEV> (Elky Bachtiar)
 * https://www.iamdeveloper.io
 */
contract Utils {

    /**
        constructor
    */
    function Utils() {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != 0x0 || _address != address(0) || _address != 0);
        _;
    }

    // validates multiple addresses - currently only checks that it isn't null
    modifier validAddresses(address _address, address _anotherAddress) {
        require((_address != 0x0         || _address != address(0)        || _address != 0 ) &&
                ( _anotherAddress != 0x0 || _anotherAddress != address(0) || _anotherAddress != 0)
        );
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // validates an uint256 input - currently only checks that it isn't empty
    modifier validInputUint256(uint256 _input) {
        bytes[] memory tempInput = new bytes[](_input);
        require(tempInput[0].length != 0);
        _;
    }

    // validates an bytes input - currently only checks that it isn't empty
    modifier validInputBytes(bytes _input) {
        bytes memory tempInput = bytes(_input);
        require(tempInput.length != 0);
        _;
    }
}


Minor changes, doc mostly

Minor changes, doc mostly

pragma solidity ^0.4.8;
import "./Owned.sol";

/*
    Open issues:
    - the formula is not yet super accurate, especially for very small/very high ratios
    - possibly support changing the CRR precision in the future

    Done:
    - need to add overflow protection
    - change exp to use a predefined constant array (for ni) instead of calculating it each call
*/

contract BancorFormula is Owned {
    uint8 constant PRECISION = 32;  // fractional bits

    string public version = '0.1';
    address public newFormula;

    function BancorFormula() {
    }

    function safeAdd(uint256 a, uint256 b) internal returns (uint){
        uint c = a + b;
        if (c < a){ throw; }
        return c;
    }
    function safeMul(uint256 a, uint256 b) internal returns (uint) {
        uint256 c = a * b;
        if ( a != 0 && c / a != b){ throw;}
        return c;
    }

    function setNewFormula(address _formula) public onlyOwner {
        newFormula = _formula;
    }

    /*
        given a token supply, reserve, CRR and a deposit amount (in the reserve token), calculates the return for a given change (in the main token)

        _supply             token total supply
        _reserveBalance     total reserve
        _reserveRatio       constant reserve ratio, 1-99
        _depositAmount      deposit amount, in reserve token
    */
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _depositAmount) public constant returns (uint256) {
        // validate input
        if (_supply == 0 || _reserveBalance == 0 || _reserveRatio < 1 || _reserveRatio > 99 || _depositAmount == 0)
            throw;

        uint256 baseN = safeAdd(_depositAmount, _reserveBalance);

        var (resN, resD) = power(baseN, _reserveBalance, _reserveRatio, 100);

        uint256 amount = safeMul(_supply, resN) / resD;

        if ( amount < _supply){
            throw;
        }

        return amount - _supply;
    }

    /*
        given a token supply, reserve, CRR and a sell amount (in the main token), calculates the return for a given change (in the reserve token)

        _supply             token total supply
        _reserveBalance     total reserve
        _reserveRatio       constant reserve ratio, 1-99
        _sellAmount         sell amount, in the token itself
    */
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _sellAmount) public constant returns (uint256) {
        // validate input
        if (_supply == 0 || _reserveBalance == 0 || _reserveRatio < 1 || _reserveRatio > 99 || _sellAmount == 0)
            throw;

        uint256 baseN = safeAdd( _sellAmount, _supply);
        var (resN, resD) = power(baseN, _supply, 100, _reserveRatio);

        uint256 amount = safeMul(_reserveBalance, resN) / resD ;

        if ( amount < _reserveBalance ){
            throw;
        }
        return amount - _reserveBalance;

    }

    /**
        Calculate (_baseN / _baseD) ^ ( _expN / _expD)
        Returns result upshifted by PRECISION

        This method throws is overflow-safe
    **/
    function power(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) constant returns (uint256 resN, uint256 resD) {

        uint256 logbase = ln(_baseN, _baseD);
        //Not using safeDiv here, since safeDiv protects against
        // precision loss. It's unavoidable, however
        // Both `ln` and `fixedExp` are overflow-safe.
        resN = fixedExp( safeMul( logbase, _expN) / _expD );

        return (resN  , uint256(1) << PRECISION);
        /*
        return (fixedExp(ln(_baseN, _baseD) * _expN / _expD), uint256(1) << PRECISION);
        */
	}

    /**
        input range:
            - numerator: [1,uint256_max >> PRECISION]
            - denominator: [1,uint256_max >> PRECISION]
        output range:
            [0,0x9b43d4f8d6]

        This method throws outside of bounds

    **/
    function ln(uint256 _numerator, uint256 _denominator) constant returns (uint256) {

        // denominator > numerator: less than one yields negative values. Unsupported
        if ( _denominator > _numerator){
            throw;
        }
        // log(1) is the lowest we can go
        if(_denominator == 0 || _numerator == 0){
            throw;
        }
        // Upper 32 bits are scaled off by PRECISION
        if(_numerator & 0xffffffff00000000000000000000000000000000000000000000000000000000 != 0){
            throw;
        }
        if(_denominator & 0xffffffff00000000000000000000000000000000000000000000000000000000 != 0){
            throw;
        }

        return fixedLoge(_numerator << PRECISION) - fixedLoge(_denominator << PRECISION);
    }

    /*
        input range:
            [0x100000000,uint256_max]
        output range:
            [0 , 0x9b43d4f8d6]

        This method throws outside of bounds

    */
    function fixedLoge(uint256 _x) constant returns (uint256 logE) {
        /*
        Since `fixedLog2` output range is max `0xdfffffffff`
        (40 bits, or 5 bytes), we can use a very large approximation
        for `ln(2)`. This one is used since it's the max accuracy
        of Python `ln(2)`

        0xb17217f7d1cf78 = ln(2) * (1 << 56)

        */
        uint256 log2 = fixedLog2(_x);
        logE = (log2 * 0xb17217f7d1cf78) >> 56;
    }
    /**
        Returns log2(x >> 32) << 32
        So x is assumed to be already upshifted 32 bits, and
        the result is also upshifted 32 bits.

        input-range :
            [0x100000000,uint256_max]
        output-range:
            [0,0xdfffffffff]

        This method throws outside of bounds

    **/
    function fixedLog2(uint256 _x) constant returns (uint256) {

        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 fixedTwo = uint256(2) << PRECISION;

        if (_x <= fixedOne){
            if ( _x == fixedOne){
                return 0;
            }
            // Numbers below 1 are negative.
            throw;
        }

        uint256 lo = 0;
        uint256 hi = 0;

        while (_x < fixedOne) {
            _x <<= 1;
            lo += fixedOne;
        }

        while (_x >= fixedTwo) {
            _x >>= 1;
            hi += fixedOne;
        }

        for (uint8 i = 0; i < PRECISION; ++i) {
            _x = (_x * _x) >> PRECISION;
            if (_x >= fixedTwo) {
                _x >>= 1;
                hi += uint256(1) << (PRECISION - 1 - i);
            }
        }
        if (lo > hi){
            //Should never happen, due to the check above
            // but this is a cheap extra check in case the
            // implementation changes over time
            throw;
        }

        return hi - lo;
    }

    /*
    fixedExp is a 'protected' version of `fixedExpUnsafe`, which
    `throw`s instead of overflows
    */
    function fixedExp(uint256 _x) constant returns (uint256) {
        if (_x > 0x386bfdba29)
            throw;
        return fixedExpUnsafe(_x);
    }
    /*
     fixedExp
     Calculates e^x according to maclauren summation:

      e^x = 1+x+x^2/2!...+x^n/n!

     and returns e^(x>>32) << 32 , that is, upshifted for accuracy

     Input range:
        - Function ok at    <= 242329958953
        - Function fails at >= 242329958954
    This method is is visible for testcases, but not meant for direct use.

    */
    function fixedExpUnsafe(uint256 _x) constant returns (uint256) {
        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 xi = fixedOne;
        uint256 res = 0xde1bc4d19efcac82445da75b00000000 * xi;

        xi = (xi * _x) >> PRECISION;
        res += xi * 0xde1bc4d19efcb0000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x6f0de268cf7e58000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x2504a0cd9a7f72000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9412833669fdc800000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1d9d4d714865f500000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x4ef8ce836bba8c0000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xb481d807d1aa68000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x16903b00fa354d000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x281cdaac677b3400000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x402e2aad725eb80000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x5d5a6c9f31fe24000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x7c7890d442a83000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9931ed540345280000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaf147cf24ce150000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d00000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xafc441338061b8000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9c3cabbc0056e000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x839168328705c80000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x694120286c04a0000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x50319e98b3d2c400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x3a52a1e36b82020;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x289286e0fce002;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1b0c59eb53400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x114f95b55400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaa7210d200;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x650139600;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x39b78e80;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1fd8080;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x10fbc0;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x8c40;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x462;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x22;

        return res / 0xde1bc4d19efcac82445da75b00000000;
    }

    function() {
        throw;
    }
}

pragma solidity ^0.4.8;
import "./Owned.sol";

/*
    Open issues:
    - the formula is not yet super accurate, especially for very small/very high ratios
    - need to add overflow protection
    - possibly support changing the CRR precision in the future
    - change exp to use a predefined constant array (for ni) instead of calculating it each call
*/

contract BancorFormula is Owned {
    uint8 constant PRECISION = 32;  // fractional bits

    string public version = '0.1';
    address public newFormula;

    function BancorFormula() {
    }

    function safeAdd(uint256 a, uint256 b) internal returns (uint){
        uint c = a + b;
        if (c < a){ throw; }
        return c;
    }
    function safeMul(uint256 a, uint256 b) internal returns (uint) {
        uint256 c = a * b;
        if ( a != 0 && c / a != b){ throw;}
        return c;
    }

    function setNewFormula(address _formula) public onlyOwner {
        newFormula = _formula;
    }

    /*
        given a token supply, reserve, CRR and a deposit amount (in the reserve token), calculates the return for a given change (in the main token)

        _supply             token total supply
        _reserveBalance     total reserve
        _reserveRatio       constant reserve ratio, 1-99
        _depositAmount      deposit amount, in reserve token
    */
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _depositAmount) public constant returns (uint256) {
        // validate input
        if (_supply == 0 || _reserveBalance == 0 || _reserveRatio < 1 || _reserveRatio > 99 || _depositAmount == 0)
            throw;

        uint256 baseN = safeAdd(_depositAmount, _reserveBalance);

        var (resN, resD) = power(baseN, _reserveBalance, _reserveRatio, 100);

        uint256 amount = safeMul(_supply, resN) / resD;

        if ( amount < _supply){
            throw;
        }

        return amount - _supply;
        /*
        var (resN, resD) = power(uint128(_depositAmount + _reserveBalance), uint128(_reserveBalance), _reserveRatio, 100);
        return (_supply * resN / resD) - _supply;
        */
    }

    /*
        given a token supply, reserve, CRR and a sell amount (in the main token), calculates the return for a given change (in the reserve token)

        _supply             token total supply
        _reserveBalance     total reserve
        _reserveRatio       constant reserve ratio, 1-99
        _sellAmount         sell amount, in the token itself
    */
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint16 _reserveRatio, uint256 _sellAmount) public constant returns (uint256) {
        // validate input
        if (_supply == 0 || _reserveBalance == 0 || _reserveRatio < 1 || _reserveRatio > 99 || _sellAmount == 0)
            throw;

        uint256 baseN = safeAdd( _sellAmount, _supply);
        var (resN, resD) = power(baseN, _supply, 100, _reserveRatio);

        uint256 amount = safeMul(_reserveBalance, resN) / resD ;

        if ( amount < _reserveBalance ){
            throw;
        }
        return amount - _reserveBalance;

        /*
        var (resN, resD) = power(uint128(_sellAmount + _supply), uint128(_supply), 100, _reserveRatio);
        return (_reserveBalance * resN / resD) - _reserveBalance;
        */

        //return (_reserveBalance * resN / resD) - _reserveBalance;
    }

    /**
        Calculate (_baseN / _baseD) ^ ( _expN / _expD)
        Returns result upshifted by PRECISION

        This method throws is overflow-safe
    **/
    function power(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) constant returns (uint256 resN, uint256 resD) {

        uint256 logbase = ln(_baseN, _baseD);
        //Not using safeDiv here, since safeDiv protects against
        // precision loss. It's unavoidable, however
        // Both `ln` and `fixedExp` are overflow-safe.
        resN = fixedExp( safeMul( logbase, _expN) / _expD );

        return (resN  , uint256(1) << PRECISION);
        /*
        return (fixedExp(ln(_baseN, _baseD) * _expN / _expD), uint256(1) << PRECISION);
        */
	}

    /**
        input range:
            - numerator: [1,uint256_max >> PRECISION]
            - denominator: [1,uint256_max >> PRECISION]
        output range:
            [0,0x9b43d4f8d6]

        This method throws outside of bounds

    **/
    function ln(uint256 _numerator, uint256 _denominator) constant returns (uint256) {

        // denominator > numerator: less than one yields negative values. Unsupported
        if ( _denominator > _numerator){
            throw;
        }
        // log(1) is the lowest we can go
        if(_denominator == 0 || _numerator == 0){
            throw;
        }
        // Upper 32 bits are scaled off by PRECISION
        if(_numerator & 0xffffffff00000000000000000000000000000000000000000000000000000000 != 0){
            throw;
        }
        if(_denominator & 0xffffffff00000000000000000000000000000000000000000000000000000000 != 0){
            throw;
        }

        return fixedLoge(_numerator << PRECISION) - fixedLoge(_denominator << PRECISION);
    }

    /*
        input range:
            [0x100000000,uint256_max]
        output range:
            [0 , 0x9b43d4f8d6]

        This method throws outside of bounds

    */
    function fixedLoge(uint256 _x) constant returns (uint256 logE) {
        /*
        Since `fixedLog2` output range is max `0xdfffffffff`
        (40 bits, or 5 bytes), we can use a very large approximation
        for `ln(2)`. This one is used since it's the max accuracy
        of Python `ln(2)`

        0xb17217f7d1cf78 = ln(2) * (1 << 56)

        */
        uint256 log2 = fixedLog2(_x);
        logE = (log2 * 0xb17217f7d1cf78) >> 56;
    }
    /**
        Returns log2(x >> 32) << 32
        So x is assumed to be already upshifted 32 bits, and
        the result is also upshifted 32 bits.

        input-range :
            [0x100000000,uint256_max]
        output-range:
            [0,0xdfffffffff]

        This method throws outside of bounds

    **/
    function fixedLog2(uint256 _x) constant returns (uint256) {

        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 fixedTwo = uint256(2) << PRECISION;

        if (_x <= fixedOne){
            if ( _x == fixedOne){
                return 0;
            }
            // Numbers below 1 are negative.
            throw;
        }

        uint256 lo = 0;
        uint256 hi = 0;

        while (_x < fixedOne) {
            _x <<= 1;
            lo += fixedOne;
        }

        while (_x >= fixedTwo) {
            _x >>= 1;
            hi += fixedOne;
        }

        for (uint8 i = 0; i < PRECISION; ++i) {
            _x = (_x * _x) >> PRECISION;
            if (_x >= fixedTwo) {
                _x >>= 1;
                hi += uint256(1) << (PRECISION - 1 - i);
            }
        }
        if (lo > hi){
            //Should never happen, due to the check above
            // but this is a cheap extra check in case the
            // implementation changes over time
            throw;
        }

        return hi - lo;
    }

    /*
    fixedExp is a 'protected' version of `fixedExpUnsafe`, which
    `throw`s instead of overflows
    */
    function fixedExp(uint256 _x) constant returns (uint256) {
        if (_x > 0x386bfdba29)
            throw;
        return fixedExpUnsafe(_x);
    }
    /*
     fixedExp
     Calculates e^x according to maclauren summation:

      e^x = 1+x+x^2/2!...+x^n/n!

     and returns e^(x>>32) << 32 , that is, upshifted for accuracy

     Input range:
        - Function ok at    <= 242329958953
        - Function fails at >= 242329958954
    This method is is visible for testcases, but not meant for direct use.

    */
    function fixedExpUnsafe(uint256 _x) constant returns (uint256) {
        uint256 fixedOne = uint256(1) << PRECISION;
        uint256 xi = fixedOne;
        uint256 res = 0xde1bc4d19efcac82445da75b00000000 * xi;

        xi = (xi * _x) >> PRECISION;
        res += xi * 0xde1bc4d19efcb0000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x6f0de268cf7e58000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x2504a0cd9a7f72000000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9412833669fdc800000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1d9d4d714865f500000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x4ef8ce836bba8c0000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xb481d807d1aa68000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x16903b00fa354d000000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x281cdaac677b3400000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x402e2aad725eb80000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x5d5a6c9f31fe24000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x7c7890d442a83000000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9931ed540345280000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaf147cf24ce150000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d000000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xbac08546b867d00000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xafc441338061b8000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x9c3cabbc0056e000000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x839168328705c80000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x694120286c04a0000;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x50319e98b3d2c400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x3a52a1e36b82020;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x289286e0fce002;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1b0c59eb53400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x114f95b55400;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0xaa7210d200;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x650139600;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x39b78e80;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x1fd8080;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x10fbc0;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x8c40;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x462;
        xi = (xi * _x) >> PRECISION;
        res += xi * 0x22;

        return res / 0xde1bc4d19efcac82445da75b00000000;
    }

    function() {
        throw;
    }
}