forked from DecentralizedClimateFoundation/DCIPs
237 lines
8.2 KiB
Solidity
237 lines
8.2 KiB
Solidity
// SPDX-License-Identifier: CC0-1.0
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pragma solidity ^0.8.0;
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import "./interface/IERC20.sol";
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import "./math/SafeMath.sol";
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/**
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* @title Standard RFT(ERC1633) token extending ERC20
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*
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* @dev Implementation of the basic standard token.
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* https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
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* Originally based on code by FirstBlood:
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* https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
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*
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* This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for
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* all accounts just by listening to said events. Note that this isn't required by the specification, and other
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* compliant implementations may not do it.
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*/
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contract FT is IERC20 {
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using SafeMath for uint256;
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mapping(address => uint256) private _balances;
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mapping(address => mapping(address => uint256)) private _allowed;
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uint256 private _totalSupply;
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// NFT Contract Address
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address private _parentToken;
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// NFT ID of NFT(RFT) - TokenId
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uint256 private _parentTokenId;
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// Admin Address to Set the Parent NFT
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address private _admin;
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constructor(uint256 total_supply) {
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_totalSupply = total_supply;
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_balances[msg.sender] = total_supply;
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_admin = msg.sender;
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}
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/**
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* @dev Total number of tokens in existence
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*/
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function totalSupply() public view override returns (uint256) {
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return _totalSupply;
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}
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/**
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* @dev Gets the balance of the specified address.
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* @param owner The address to query the balance of.
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* @return An uint256 representing the amount owned by the passed address.
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*/
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function balanceOf(address owner) public view override returns (uint256) {
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return _balances[owner];
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}
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/**
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* @dev Function to check the amount of tokens that an owner allowed to a spender.
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* @param owner address The address which owns the funds.
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* @param spender address The address which will spend the funds.
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* @return A uint256 specifying the amount of tokens still available for the spender.
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*/
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function allowance(address owner, address spender)
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public
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view
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override
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returns (uint256)
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{
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return _allowed[owner][spender];
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}
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/**
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* @dev Transfer token for a specified address
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* @param to The address to transfer to.
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* @param value The amount to be transferred.
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*/
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function transfer(address to, uint256 value)
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public
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override
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returns (bool)
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{
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_transfer(msg.sender, to, value);
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return true;
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}
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/**
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* @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
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* Beware that changing an allowance with this method brings the risk that someone may use both the old
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* and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
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* race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
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* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
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* @param spender The address which will spend the funds.
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* @param value The amount of tokens to be spent.
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*/
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function approve(address spender, uint256 value)
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public
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override
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returns (bool)
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{
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require(spender != address(0));
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_allowed[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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/**
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* @dev Transfer tokens from one address to another.
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* Note that while this function emits an Approval event, this is not required as per the specification,
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* and other compliant implementations may not emit the event.
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* @param from address The address which you want to send tokens from
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* @param to address The address which you want to transfer to
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* @param value uint256 the amount of tokens to be transferred
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*/
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function transferFrom(
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address from,
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address to,
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uint256 value
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) public override returns (bool) {
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_allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
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_transfer(from, to, value);
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emit Approval(from, msg.sender, _allowed[from][msg.sender]);
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return true;
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}
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/**
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* @dev Increase the amount of tokens that an owner allowed to a spender.
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* approve should be called when allowed_[_spender] == 0. To increment
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* allowed value is better to use this function to avoid 2 calls (and wait until
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* the first transaction is mined)
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* From MonolithDAO Token.sol
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* Emits an Approval event.
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* @param spender The address which will spend the funds.
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* @param addedValue The amount of tokens to increase the allowance by.
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*/
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function increaseAllowance(address spender, uint256 addedValue)
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public
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returns (bool)
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{
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require(spender != address(0));
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_allowed[msg.sender][spender] = _allowed[msg.sender][spender].add(
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addedValue
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);
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emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
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return true;
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}
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/**
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* @dev Decrease the amount of tokens that an owner allowed to a spender.
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* approve should be called when allowed_[_spender] == 0. To decrement
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* allowed value is better to use this function to avoid 2 calls (and wait until
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* the first transaction is mined)
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* From MonolithDAO Token.sol
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* Emits an Approval event.
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* @param spender The address which will spend the funds.
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* @param subtractedValue The amount of tokens to decrease the allowance by.
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*/
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function decreaseAllowance(address spender, uint256 subtractedValue)
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public
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returns (bool)
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{
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require(spender != address(0));
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_allowed[msg.sender][spender] = _allowed[msg.sender][spender].sub(
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subtractedValue
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);
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emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
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return true;
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}
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/**
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* @dev Transfer token for a specified addresses
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* @param from The address to transfer from.
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* @param to The address to transfer to.
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* @param value The amount to be transferred.
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*/
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function _transfer(
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address from,
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address to,
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uint256 value
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) internal {
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require(to != address(0));
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_balances[from] = _balances[from].sub(value);
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_balances[to] = _balances[to].add(value);
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emit Transfer(from, to, value);
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}
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/**
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* @dev Internal function that mints an amount of the token and assigns it to
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* an account. This encapsulates the modification of balances such that the
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* proper events are emitted.
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* @param account The account that will receive the created tokens.
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* @param value The amount that will be created.
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*/
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function _mint(address account, uint256 value) internal {
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require(account != address(0));
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_totalSupply = _totalSupply.add(value);
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_balances[account] = _balances[account].add(value);
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emit Transfer(address(0), account, value);
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}
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/**
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* @dev Internal function that burns an amount of the token of a given
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* account.
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* @param account The account whose tokens will be burnt.
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* @param value The amount that will be burnt.
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*/
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function _burn(address account, uint256 value) internal {
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require(account != address(0));
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_totalSupply = _totalSupply.sub(value);
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_balances[account] = _balances[account].sub(value);
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emit Transfer(account, address(0), value);
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}
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/**
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* @dev Internal function that burns an amount of the token of a given
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* account, deducting from the sender's allowance for said account. Uses the
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* internal burn function.
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* Emits an Approval event (reflecting the reduced allowance).
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* @param account The account whose tokens will be burnt.
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* @param value The amount that will be burnt.
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*/
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function _burnFrom(address account, uint256 value) internal {
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_allowed[account][msg.sender] = _allowed[account][msg.sender].sub(
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value
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);
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_burn(account, value);
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emit Approval(account, msg.sender, _allowed[account][msg.sender]);
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}
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}
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