67 lines
2.0 KiB
Plaintext
67 lines
2.0 KiB
Plaintext
|
// https://github.com/nexusdev/erc20/blob/master/contracts/base.sol
|
||
|
|
|
||
|
|
pragma solidity ^0.4.2;
|
||
|
|
contract Token {
|
||
|
|
|
||
|
|
event Transfer(address indexed from, address indexed to, uint value);
|
||
|
|
event Approval( address indexed owner, address indexed spender, uint value);
|
||
|
|
|
||
|
|
mapping( address => uint ) _balances;
|
||
|
|
mapping( address => mapping( address => uint ) ) _approvals;
|
||
|
|
uint public _supply;
|
||
|
|
//uint public _supply2;
|
||
|
|
function Token( uint initial_balance ) {
|
||
|
|
_balances[msg.sender] = initial_balance;
|
||
|
|
_supply = initial_balance;
|
||
|
|
}
|
||
|
|
function totalSupply() constant returns (uint supply) {
|
||
|
|
return _supply;
|
||
|
|
}
|
||
|
|
function balanceOf( address who ) constant returns (uint value) {
|
||
|
|
return _balances[who];
|
||
|
|
}
|
||
|
|
function transfer( address to, uint value) returns (bool ok) {
|
||
|
|
if( _balances[msg.sender] < value ) {
|
||
|
|
throw;
|
||
|
|
}
|
||
|
|
if( !safeToAdd(_balances[to], value) ) {
|
||
|
|
throw;
|
||
|
|
}
|
||
|
|
_balances[msg.sender] -= value;
|
||
|
|
_balances[to] += value;
|
||
|
|
Transfer( msg.sender, to, value );
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
function transferFrom( address from, address to, uint value) returns (bool ok) {
|
||
|
|
// if you don't have enough balance, throw
|
||
|
|
if( _balances[from] < value ) {
|
||
|
|
throw;
|
||
|
|
}
|
||
|
|
// if you don't have approval, throw
|
||
|
|
if( _approvals[from][msg.sender] < value ) {
|
||
|
|
throw;
|
||
|
|
}
|
||
|
|
if( !safeToAdd(_balances[to], value) ) {
|
||
|
|
throw;
|
||
|
|
}
|
||
|
|
// transfer and return true
|
||
|
|
_approvals[from][msg.sender] -= value;
|
||
|
|
_balances[from] -= value;
|
||
|
|
_balances[to] += value;
|
||
|
|
Transfer( from, to, value );
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
function approve(address spender, uint value) returns (bool ok) {
|
||
|
|
// TODO: should increase instead
|
||
|
|
_approvals[msg.sender][spender] = value;
|
||
|
|
Approval( msg.sender, spender, value );
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
function allowance(address owner, address spender) constant returns (uint _allowance) {
|
||
|
|
return _approvals[owner][spender];
|
||
|
|
}
|
||
|
|
function safeToAdd(uint a, uint b) internal returns (bool) {
|
||
|
|
return (a + b >= a);
|
||
|
|
}
|
||
|
|
}
|