toLower.sol

contract LCS {
    function toLowerCase(string _in){// returns (string){
        bytes memory _out_b = bytes(_in);
        byte tmp;
        for (uint i=0; i<_out_b.length; i++){
            tmp = _out_b[i];
            if (tmp < 91) _out_b[i] = byte(int(tmp)+32);
        }
        //return string(_out_b);
    }
    
    function toLowerCase_asm(string _in){// returns (string){
        assembly {
                let ptr := add(_in, 32)
                let str := mload(ptr)
                let offset := 0
                let char := 0
            loop:
                char := byte(offset, str)
                jumpi(end, eq(char, 0))
                jumpi(toLower, lt(char, 91))
                jump(skip)
            toLower:
                mstore8(add(ptr, offset), add(char, 32))
            skip:
                offset := add(offset, 1)
                jumpi(end, eq(offset, 32))
                jump(loop)
            end:
        }
    }
}