smart contract to encode ABI keys

ABIencoding.sol

pragma solidity ^0.4.11;

contract ABIparams{
    
    // call this with the function name and types but not variable names
    // make sure there are no spaces
    // e.g. "transfer(address,uint256)"
    function hash(string str) public constant returns (bytes4) {
        return (bytes4(sha3(str)));
    }
    
    // encode an addess by adding the necessary number of zeros for it to
    // be used in an ABI encoded parameter
    function addressVal(address a) public constant returns (bytes32) {
        return bytes32(a);
    }
    
    // display an integer number in hex so that it can
    // be used in an ABI encoded parameter
    function num(uint256 n)  public constant returns (bytes32) {
        return bytes32(n);
    }
    
    // show an integer number as that number of ether so that it can
    // be used in an ABI encoded parameter
    function numInEther(uint256 n) public constant returns (bytes32) {
        return num(n * 1 ether);
    }
    
    // get ABI code for transfer function where you specify the value exactly
    function transferInUnits(address a, uint256 v)public constant returns (bytes4 hv,bytes32 av,bytes32 vv) {
        hv = hash("transfer(address,uint256)");
        av = addressVal(a);
        vv = num(v);
        return;
    }

    // get ABI code for transfer function where you specify the value in tokens 
    // which has 'decimal' places (eg 1 ether -> decimal = 18)
    function transferInDecimals(address a, uint256 v, uint256 decimals)public constant returns (bytes4 hv,bytes32 av,bytes32 vv) {
        hv = hash("transfer(address,uint256)");
        av = addressVal(a);
        vv = num(v * 10 ** decimals);
        return;
    }

    // get ABI code for approve function where you specify the value exactly
    function approve(address a, uint256 v) public constant returns (bytes4 hv,bytes32 av, bytes32 vv) {
        hv = hash("approve(address,uint256)");
        av = addressVal(a);
        vv = num(v);
        return;
    }
    
    // get ABI code for approve function where you specify the value in tokens 
    // which has 'decimal' places (eg 1 ether -> decimal = 18)
    function approveInDecimals(address a, uint256 v, uint256 decimals)public constant returns (bytes4 hv,bytes32 av,bytes32 vv) {
        hv = hash("approve(address,uint256)");
        av = addressVal(a);
        vv = num(v * 10 ** decimals);
        return;
    }
    
    // get ABI code for transferFrom function where you specify the value exactly
    function transferFromInUnits(address from, address to, uint256 v)public constant returns (bytes4 hv,bytes32 av1, bytes32 av2,bytes32 vv) {
        hv = hash("transferFrom(address,address,uint256)");
        av1 = addressVal(from);
        av2 = addressVal(to);
        vv = num(v);
        return;
    }
    
    // get ABI code for transferFrom function where you specify the value in tokens 
    // which has 'decimal' places (eg 1 ether -> decimal = 18)
    function transferFromInDecimals(address from, address to, uint256 v, uint256 decimals)public constant returns (bytes4 hv,bytes32 av1, bytes32 av2,bytes32 vv) {
        hv = hash("transferFrom(address,address,uint256)");
        av1 = addressVal(from);
        av2 = addressVal(to);
        vv = num(v * 10 ** decimals);
        return;
    }

    

}