systemcontract/StringTool.sol

pragma solidity ^0.4.4;


contract StringTool {
    function compare(string _a, string _b) returns (int) {
        bytes memory a = bytes(_a);
        bytes memory b = bytes(_b);
        uint minLength = a.length;
        if (b.length < minLength) minLength = b.length;
        //@todo unroll the loop into increments of 32 and do full 32 byte comparisons
        for (uint i = 0; i < minLength; i ++)
            if (a[i] < b[i])
                return -1;
            else if (a[i] > b[i])
                return 1;
        if (a.length < b.length)
            return -1;
        else if (a.length > b.length)
            return 1;
        else
            return 0;
    }
    /// @dev Compares two strings and returns true iff they are equal.
    function equal(string _a, string _b) returns (bool) {
        return compare(_a, _b) == 0;
    }

    function byte64ToString(byte[64] x) constant returns (string) {
        bytes memory bytesString = new bytes(64);
        uint charCount = 0;
        for (uint j = 0; j < 64; j++) {
            if (x[j] != 0) {
                bytesString[charCount] = x[j];
                charCount++;
            }
        }
        bytes memory bytesStringTrimmed = new bytes(charCount);
        for (j = 0; j < charCount; j++) {
            bytesStringTrimmed[j] = bytesString[j];
        }
        return string(bytesStringTrimmed);
    } 

    function byte32ArrayToString(byte[32] x) internal constant returns (string) {
        bytes memory bytesString = new bytes(32);
        uint charCount = 0;
        for (uint j = 0; j < 32; j++) {
            if (x[j] != 0) {
                bytesString[charCount] = x[j];
                charCount++;
            }
        }
        bytes memory bytesStringTrimmed = new bytes(charCount);
        for (j = 0; j < charCount; j++) {
            bytesStringTrimmed[j] = bytesString[j];
        }
        return string(bytesStringTrimmed);
    } 

    function stringToByte32Array(string str) internal constant returns (byte[32]) {
        bytes memory tmp = bytes(str);
        byte[32] memory value;
        for (uint i = 0; i < 32 && i < tmp.length; i++)
            value[i] = tmp[i];
        return value;
    }

    function bytes32ToString(bytes32 x) constant returns (string) {
        bytes memory bytesString = new bytes(32);
        uint charCount = 0;
        for (uint j = 0; j < 32; j++) {
            byte char = byte(bytes32(uint(x) * 2 ** (8 * j)));
            if (char != 0) {
                bytesString[charCount] = char;
                charCount++;
            }
        }
        bytes memory bytesStringTrimmed = new bytes(charCount);
        for (j = 0; j < charCount; j++) {
            bytesStringTrimmed[j] = bytesString[j];
        }
        return string(bytesStringTrimmed);
    }

    function stringToBytes32(string memory source) returns (bytes32 result) {
        bytes memory tempEmptyStringTest = bytes(source);
        if (tempEmptyStringTest.length == 0) {
            return 0x0;
        }

        assembly {
            result := mload(add(source, 32))
        }
    }
}