dsa-connectors/contracts/mainnet/common/basic.sol

//SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;

import { TokenInterface } from "./interfaces.sol";
import { Stores } from "./stores.sol";
import { DSMath } from "./math.sol";

abstract contract Basic is DSMath, Stores {

    function convert18ToDec(uint _dec, uint256 _amt) internal pure returns (uint256 amt) {
        amt = (_amt / 10 ** (18 - _dec));
    }

    function convertTo18(uint _dec, uint256 _amt) internal pure returns (uint256 amt) {
        amt = mul(_amt, 10 ** (18 - _dec));
    }

    function getTokenBal(TokenInterface token) internal view returns(uint _amt) {
        _amt = address(token) == ethAddr ? address(this).balance : token.balanceOf(address(this));
    }

    function getTokensDec(TokenInterface buyAddr, TokenInterface sellAddr) internal view returns(uint buyDec, uint sellDec) {
        buyDec = address(buyAddr) == ethAddr ?  18 : buyAddr.decimals();
        sellDec = address(sellAddr) == ethAddr ?  18 : sellAddr.decimals();
    }

    function encodeEvent(string memory eventName, bytes memory eventParam) internal pure returns (bytes memory) {
        return abi.encode(eventName, eventParam);
    }

    function approve(TokenInterface token, address spender, uint256 amount) internal {
        try token.approve(spender, amount) {

        } catch {
            token.approve(spender, 0);
            token.approve(spender, amount);
        }
    }

    function changeEthAddress(address buy, address sell) internal pure returns(TokenInterface _buy, TokenInterface _sell){
        _buy = buy == ethAddr ? TokenInterface(wethAddr) : TokenInterface(buy);
        _sell = sell == ethAddr ? TokenInterface(wethAddr) : TokenInterface(sell);
    }

    function changeEthAddrToWethAddr(address token) internal pure returns(address tokenAddr){
        tokenAddr = token == ethAddr ? wethAddr : token;
    }

    function convertEthToWeth(bool isEth, TokenInterface token, uint amount) internal {
        if(isEth) token.deposit{value: amount}();
    }

    function convertWethToEth(bool isEth, TokenInterface token, uint amount) internal {
       if(isEth) {
            approve(token, address(token), amount);
            token.withdraw(amount);
        }
    }
}