5f7eda1f98
* Tokens: wrap definitely safe subs in unchecked * Add change in changelog Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>
43 lines
1.2 KiB
Solidity
43 lines
1.2 KiB
Solidity
// SPDX-License-Identifier: MIT
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pragma solidity ^0.8.0;
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import "../ERC20.sol";
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import "../../../utils/Context.sol";
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/**
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* @dev Extension of {ERC20} that allows token holders to destroy both their own
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* tokens and those that they have an allowance for, in a way that can be
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* recognized off-chain (via event analysis).
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*/
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abstract contract ERC20Burnable is Context, ERC20 {
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/**
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* @dev Destroys `amount` tokens from the caller.
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*
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* See {ERC20-_burn}.
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*/
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function burn(uint256 amount) public virtual {
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_burn(_msgSender(), amount);
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}
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/**
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* @dev Destroys `amount` tokens from `account`, deducting from the caller's
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* allowance.
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*
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* See {ERC20-_burn} and {ERC20-allowance}.
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*
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* Requirements:
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*
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* - the caller must have allowance for ``accounts``'s tokens of at least
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* `amount`.
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*/
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function burnFrom(address account, uint256 amount) public virtual {
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uint256 currentAllowance = allowance(account, _msgSender());
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require(currentAllowance >= amount, "ERC20: burn amount exceeds allowance");
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unchecked {
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_approve(account, _msgSender(), currentAllowance - amount);
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}
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_burn(account, amount);
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}
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}
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