mirror of https://github.com/embarklabs/embark.git
70 lines
2.1 KiB
Solidity
70 lines
2.1 KiB
Solidity
// https://github.com/nexusdev/erc20/blob/master/contracts/base.sol
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pragma solidity ^0.4.17;
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contract Token {
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event Transfer(address indexed from, address indexed to, uint value);
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event Approval( address indexed owner, address indexed spender, uint value);
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mapping( address => uint ) _balances;
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mapping( address => mapping( address => uint ) ) _approvals;
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uint public _supply;
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//uint public _supply2;
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constructor( uint initial_balance ) public {
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_balances[msg.sender] = initial_balance;
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_supply = initial_balance;
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}
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function totalSupply() public constant returns (uint supply) {
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return _supply;
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}
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function balanceOf( address who ) public constant returns (uint value) {
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return _balances[who];
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}
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function transfer( address to, uint value) public returns (bool ok) {
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if( _balances[msg.sender] < value ) {
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revert();
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}
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if( !safeToAdd(_balances[to], value) ) {
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revert();
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}
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_balances[msg.sender] -= value;
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_balances[to] += value;
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emit Transfer( msg.sender, to, value );
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return true;
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}
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function transferFrom( address from, address to, uint value) public returns (bool ok) {
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// if you don't have enough balance, throw
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if( _balances[from] < value ) {
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revert();
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}
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// if you don't have approval, throw
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if( _approvals[from][msg.sender] < value ) {
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revert();
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}
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if( !safeToAdd(_balances[to], value) ) {
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revert();
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}
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// transfer and return true
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_approvals[from][msg.sender] -= value;
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_balances[from] -= value;
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_balances[to] += value;
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emit Transfer( from, to, value );
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return true;
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}
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function approve(address spender, uint value) public returns (bool ok) {
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// TODO: should increase instead
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_approvals[msg.sender][spender] = value;
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emit Approval( msg.sender, spender, value );
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return true;
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}
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function allowance(address owner, address spender) public constant returns (uint _allowance) {
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return _approvals[owner][spender];
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}
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function safeToAdd(uint a, uint b) internal pure returns (bool) {
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return (a + b >= a);
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}
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function isAvailable() public pure returns (bool) {
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return false;
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}
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}
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