-
Notifications
You must be signed in to change notification settings - Fork 1
/
UTOToken.sol
159 lines (144 loc) · 5.82 KB
/
UTOToken.sol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
pragma solidity ^0.4.18;
import {SafeMath} from "./SafeMath.sol";
interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external; }
contract UTOToken {
// Public variables of the token
string public name="UTour";
string public symbol="UTO";
uint8 public decimals = 18;
// 18 decimals is the strongly suggested default, avoid changing it
uint256 public totalSupply=3 * 10 ** 26;
// This creates an array with all balances
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;
// This generates a public event on the blockchain that will notify clients
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);
/**
* Constructor function
*
* Initializes contract with initial supply tokens to the creator of the contract
*/
// function UTOToken() public {
constructor () public {
balanceOf[msg.sender] = totalSupply; // Give the creator all initial tokens
}
/**
* Internal transfer, only can be called by this contract
*/
function _transfer(address _from, address _to, uint _value) internal {
// Prevent transfer to 0x0 address. Use burn() instead
require(_to != 0x0);
// Subtract from the sender
balanceOf[_from] = SafeMath.sub(balanceOf[_from], _value);
// Add the same to the recipient
balanceOf[_to] = SafeMath.add(balanceOf[_to], _value);
emit Transfer(_from, _to, _value);
}
/**
* Transfer tokens
*
* Send `_value` tokens to `_to` from your account
*
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transfer(address _to, uint256 _value) public returns (bool success) {
_transfer(msg.sender, _to, _value);
return true;
}
/**
* Transfer tokens from other address
*
* Send `_value` tokens to `_to` on behalf of `_from`
*
* @param _from The address of the sender
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
// Check allowance
allowance[_from][msg.sender] = SafeMath.sub(allowance[_from][msg.sender], _value);
_transfer(_from, _to, _value);
return true;
}
/**
* Set allowance for other address
*
* Allows `_spender` to spend no more than `_value` tokens on your behalf
*
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
*/
function approve(address _spender, uint256 _value) public returns (bool success) {
allowance[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* Set allowance for other address and notify
*
* Allows `_spender` to spend no more than `_value` tokens on your behalf, and then ping the contract about it
*
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
* @param _extraData some extra information to send to the approved contract
*/
function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) {
tokenRecipient spender = tokenRecipient(_spender);
if (approve(_spender, _value)) {
spender.receiveApproval(msg.sender, _value, this, _extraData);
return true;
}
}
function increaseApproval (address _spender, uint _addedValue) public returns (bool success) {
allowance[msg.sender][_spender] = SafeMath.add(allowance[msg.sender][_spender], _addedValue);
emit Approval(msg.sender, _spender, allowance[msg.sender][_spender]);
return true;
}
function decreaseApproval (address _spender, uint _subtractedValue) public returns (bool success) {
uint oldValue = allowance[msg.sender][_spender];
if (_subtractedValue > oldValue) {
allowance[msg.sender][_spender] = 0;
} else {
allowance[msg.sender][_spender] = SafeMath.sub(oldValue, _subtractedValue);
}
emit Approval(msg.sender, _spender, allowance[msg.sender][_spender]);
return true;
}
/**
* Destroy tokens
*
* Remove `_value` tokens from the system irreversibly
*
* @param _value the amount of money to burn
*/
function burn(uint256 _value) public returns (bool success) {
// Subtract from the sender
balanceOf[msg.sender] = SafeMath.sub(balanceOf[msg.sender], _value);
// Updates totalSupply
totalSupply = SafeMath.sub(totalSupply, _value);
emit Burn(msg.sender, _value);
return true;
}
/**
* Destroy tokens from other account
*
* Remove `_value` tokens from the system irreversibly on behalf of `_from`.
*
* @param _from the address of the sender
* @param _value the amount of money to burn
*/
function burnFrom(address _from, uint256 _value) public returns (bool success) {
// Subtract from the targeted balance
balanceOf[_from] = SafeMath.sub(balanceOf[_from], _value);
// Subtract from the sender's allowance
allowance[_from][msg.sender] = SafeMath.sub(allowance[_from][msg.sender], _value);
// Update totalSupply
totalSupply = SafeMath.sub(totalSupply, _value);
emit Burn(_from, _value);
return true;
}
}