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ERC20Capped.sol
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ERC20Capped.sol
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pragma solidity ^0.5.0;
import "./ERC20Mintable.sol";
/**
* @dev Extension of {ERC20Mintable} that adds a cap to the supply of tokens.
*/
contract ERC20Capped is ERC20Mintable {
uint256 private _cap;
/**
* @dev Sets the value of the `cap`. This value is immutable, it can only be
* set once during construction.
*/
constructor (uint256 cap) public {
require(cap > 0, "ERC20Capped: cap is 0");
_cap = cap;
}
/**
* @dev Returns the cap on the token's total supply.
*/
function cap() public view returns (uint256) {
return _cap;
}
/**
* @dev See {ERC20Mintable-mint}.
*
* Requirements:
*
* - `value` must not cause the total supply to go over the cap.
*/
function _mint(address account, uint256 value) internal {
require(totalSupply().add(value) <= _cap, "ERC20Capped: cap exceeded");
super._mint(account, value);
}
}