Uniswap V2

0x76818d1ef0465e8ce9923dd89194faaa561db38c Copy

ERC20

This contract is an ERC20 token.

Name Uniswap V2

Symbol UNI-V2

Decimals 18

Total Supply 25,298 UNI-V2

About

Stats

Public Functions 11

Event Types 6

Code Size 20,872 bytes

Library Use

Uses SafeMath for uint.

Uses UQ112x112 for uint224.

Events (6)

Approval Event

Parameters

owner	address
spender	address
value	uint

Burn Event

Parameters

sender	address
amount0	uint
amount1	uint
to	address

Mint Event

Parameters

sender	address
amount0	uint
amount1	uint

Swap Event

Parameters

sender	address
amount0In	uint
amount1In	uint
amount0Out	uint
amount1Out	uint
to	address

Sync Event

Parameters

reserve0	uint112
reserve1	uint112

Transfer Event

Parameters

from	address
to	address
value	uint

Constants (6)

MINIMUM_LIQUIDITY Constant

uint

UNKNOWN VALUE

SELECTOR Constant

bytes4

UNKNOWN VALUE

name Constant

string

Uniswap V2

symbol Constant

string

UNI-V2

decimals Constant

uint8

PERMIT_TYPEHASH Constant

bytes32

0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9

State Variables (15)

factory Variable

address

token0 Variable

address

token1 Variable

address

price0CumulativeLast Variable

uint

price1CumulativeLast Variable

uint

kLast Variable

uint

totalSupply Variable

uint

DOMAIN_SEPARATOR Variable

bytes32

balanceOf Variable

mapping(address => uint)

nonces Variable

mapping(address => uint)

reserve0 Variable

uint112

Internal Variable

reserve1 Variable

uint112

Internal Variable

blockTimestampLast Variable

uint32

Internal Variable

unlocked Variable

uint

Internal Variable

allowance Variable

mapping(address => mapping(address => uint))

Internal Variable

Functions Expand All Collapse All

approve

Parameters

Name	Type
spender	address
value	uint

Properties

Visibility public

Mutability transaction

Source Code

function approve(address spender, uint256 value) external returns (bool) {
  _approve(msg.sender, spender, value);
  return true;
}

transfer

Parameters

Name	Type
to	address
value	uint

Properties

Visibility public

Mutability transaction

Source Code

function transfer(address to, uint256 value) external returns (bool) {
  _transfer(msg.sender, to, value);
  return true;
}

transferFrom

Parameters

Name	Type
from	address
to	address
value	uint

Properties

Visibility public

Mutability transaction

Source Code

function transferFrom(
  address from,
  address to,
  uint256 value
) external returns (bool) {
  if (allowance[from][msg.sender] != uint256(-1)) {
    allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
  }
  _transfer(from, to, value);
  return true;
}

permit

Parameters

Name	Type
owner	address
spender	address
value	uint
deadline	uint
v	uint8
r	bytes32
s	bytes32

Properties

Visibility public

Mutability transaction

Requirements

deadline must be greater than or equal to block.timestamp

recoveredAddress must be equal to owner

recoveredAddress must not be equal to UNKNOWN VALUE

Source Code

function permit(
  address owner,
  address spender,
  uint256 value,
  uint256 deadline,
  uint8 v,
  bytes32 r,
  bytes32 s
) external {
  require(deadline >= block.timestamp, "UniswapV2: EXPIRED");
  bytes32 digest = keccak256(
    abi.encodePacked(
      "\x19\x01",
      DOMAIN_SEPARATOR,
      keccak256(
        abi.encode(
          PERMIT_TYPEHASH,
          owner,
          spender,
          value,
          nonces[owner]++,
          deadline
        )
      )
    )
  );
  address recoveredAddress = ecrecover(digest, v, r, s);
  require(
    recoveredAddress != address(0) && recoveredAddress == owner,
    "UniswapV2: INVALID_SIGNATURE"
  );
  _approve(owner, spender, value);
}

getReserves

Parameters

This function has no parameters.

Properties

Visibility public

Mutability view

Source Code

function getReserves()
  public
  view
  returns (
    uint112 _reserve0,
    uint112 _reserve1,
    uint32 _blockTimestampLast
  )
{
  _reserve0 = reserve0;
  _reserve1 = reserve1;
  _blockTimestampLast = blockTimestampLast;
}

initialize

Parameters

Name	Type
_token0	address
_token1	address

Properties

Visibility public

Mutability transaction

Requirements

factory must be equal to the sender's address

Source Code

function initialize(address _token0, address _token1) external {
  require(msg.sender == factory, "UniswapV2: FORBIDDEN"); // sufficient check
  token0 = _token0;
  token1 = _token1;
}

mint

Parameters

Name	Type
to	address

Properties

Visibility public

Mutability transaction

Modifiers

lock checks for the following:

unlocked must be equal to 1

Requirements

liquidity must be greater than 0

balance1 must be less than or equal to UNKNOWN VALUE

balance0 must be less than or equal to UNKNOWN VALUE

Source Code

function mint(address to) external lock returns (uint256 liquidity) {
  (uint112 _reserve0, uint112 _reserve1, ) = getReserves(); // gas savings
  uint256 balance0 = IERC20(token0).balanceOf(address(this));
  uint256 balance1 = IERC20(token1).balanceOf(address(this));
  uint256 amount0 = balance0.sub(_reserve0);
  uint256 amount1 = balance1.sub(_reserve1);

  bool feeOn = _mintFee(_reserve0, _reserve1);
  uint256 _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
  if (_totalSupply == 0) {
    liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
    _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
  } else {
    liquidity = Math.min(
      amount0.mul(_totalSupply) / _reserve0,
      amount1.mul(_totalSupply) / _reserve1
    );
  }
  require(liquidity > 0, "UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED");
  _mint(to, liquidity);

  _update(balance0, balance1, _reserve0, _reserve1);
  if (feeOn) kLast = uint256(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
  emit Mint(msg.sender, amount0, amount1);
}

burn

Parameters

Name	Type
to	address

Properties

Visibility public

Mutability transaction

Modifiers

lock checks for the following:

unlocked must be equal to 1

Requirements

amount1 must be greater than 0

amount0 must be greater than 0

success must be true

balance1 must be less than or equal to UNKNOWN VALUE

balance0 must be less than or equal to UNKNOWN VALUE

Source Code

function burn(address to)
  external
  lock
  returns (uint256 amount0, uint256 amount1)
{
  (uint112 _reserve0, uint112 _reserve1, ) = getReserves(); // gas savings
  address _token0 = token0; // gas savings
  address _token1 = token1; // gas savings
  uint256 balance0 = IERC20(_token0).balanceOf(address(this));
  uint256 balance1 = IERC20(_token1).balanceOf(address(this));
  uint256 liquidity = balanceOf[address(this)];

  bool feeOn = _mintFee(_reserve0, _reserve1);
  uint256 _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
  amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
  amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
  require(
    amount0 > 0 && amount1 > 0,
    "UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED"
  );
  _burn(address(this), liquidity);
  _safeTransfer(_token0, to, amount0);
  _safeTransfer(_token1, to, amount1);
  balance0 = IERC20(_token0).balanceOf(address(this));
  balance1 = IERC20(_token1).balanceOf(address(this));

  _update(balance0, balance1, _reserve0, _reserve1);
  if (feeOn) kLast = uint256(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
  emit Burn(msg.sender, amount0, amount1, to);
}

swap

Parameters

Name	Type
amount0Out	uint
amount1Out	uint
to	address
data	bytes

Properties

Visibility public

Mutability transaction

Modifiers

lock checks for the following:

unlocked must be equal to 1

Requirements

One or more of the following: - amount1Out must be greater than 0 - OR amount0Out must be greater than 0

amount1Out must be less than _reserve1

amount0Out must be less than _reserve0

One or more of the following: - amount1In must be greater than 0 - OR amount0In must be greater than 0

balance1 must be less than or equal to UNKNOWN VALUE

balance0 must be less than or equal to UNKNOWN VALUE

Source Code

function swap(
  uint256 amount0Out,
  uint256 amount1Out,
  address to,
  bytes calldata data
) external lock {
  require(
    amount0Out > 0 || amount1Out > 0,
    "UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT"
  );
  (uint112 _reserve0, uint112 _reserve1, ) = getReserves(); // gas savings
  require(
    amount0Out < _reserve0 && amount1Out < _reserve1,
    "UniswapV2: INSUFFICIENT_LIQUIDITY"
  );

  uint256 balance0;
  uint256 balance1;
  {
    // scope for _token{0,1}, avoids stack too deep errors
    address _token0 = token0;
    address _token1 = token1;
    require(to != _token0 && to != _token1, "UniswapV2: INVALID_TO");
    if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
    if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
    if (data.length > 0)
      IUniswapV2Callee(to).uniswapV2Call(
        msg.sender,
        amount0Out,
        amount1Out,
        data
      );
    balance0 = IERC20(_token0).balanceOf(address(this));
    balance1 = IERC20(_token1).balanceOf(address(this));
  }
  uint256 amount0In = balance0 > _reserve0 - amount0Out
    ? balance0 - (_reserve0 - amount0Out)
    : 0;
  uint256 amount1In = balance1 > _reserve1 - amount1Out
    ? balance1 - (_reserve1 - amount1Out)
    : 0;
  require(
    amount0In > 0 || amount1In > 0,
    "UniswapV2: INSUFFICIENT_INPUT_AMOUNT"
  );
  {
    // scope for reserve{0,1}Adjusted, avoids stack too deep errors
    uint256 balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
    uint256 balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
    require(
      balance0Adjusted.mul(balance1Adjusted) >=
        uint256(_reserve0).mul(_reserve1).mul(1000**2),
      "UniswapV2: K"
    );
  }

  _update(balance0, balance1, _reserve0, _reserve1);
  emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
}

skim

Parameters

Name	Type
to	address

Properties

Visibility public

Mutability transaction

Modifiers

lock checks for the following:

unlocked must be equal to 1

Requirements

success must be true

Source Code

function skim(address to) external lock {
  address _token0 = token0; // gas savings
  address _token1 = token1; // gas savings
  _safeTransfer(
    _token0,
    to,
    IERC20(_token0).balanceOf(address(this)).sub(reserve0)
  );
  _safeTransfer(
    _token1,
    to,
    IERC20(_token1).balanceOf(address(this)).sub(reserve1)
  );
}

sync

Parameters

This function has no parameters.

Properties

Visibility public

Mutability transaction

Modifiers

lock checks for the following:

unlocked must be equal to 1

Requirements

UNKNOWN VALUE must be less than or equal to UNKNOWN VALUE

Source Code

function sync() external lock {
  _update(
    IERC20(token0).balanceOf(address(this)),
    IERC20(token1).balanceOf(address(this)),
    reserve0,
    reserve1
  );
}

Internal Functions Expand All Collapse All

Internal functions are parts of the contract that can't be used directly, but instead are used by the public functions listed above.

internal UniswapV2Pair._safeTransfer

Parameters

Name	Type
token	address
to	address
value	uint

Properties

Visibility private

Mutability transaction

Requirements

success must be true

Source Code

function _safeTransfer(
  address token,
  address to,
  uint256 value
) private {
  (bool success, bytes memory data) = token.call(
    abi.encodeWithSelector(SELECTOR, to, value)
  );
  require(
    success && (data.length == 0 || abi.decode(data, (bool))),
    "UniswapV2: TRANSFER_FAILED"
  );
}

internal UniswapV2Pair._update

Parameters

Name	Type
balance0	uint
balance1	uint
_reserve0	uint112
_reserve1	uint112

Properties

Visibility private

Mutability transaction

Requirements

UNKNOWN VALUE must be less than or equal to UNKNOWN VALUE

Source Code

function _update(
  uint256 balance0,
  uint256 balance1,
  uint112 _reserve0,
  uint112 _reserve1
) private {
  require(
    balance0 <= uint112(-1) && balance1 <= uint112(-1),
    "UniswapV2: OVERFLOW"
  );
  uint32 blockTimestamp = uint32(block.timestamp % 2**32);
  uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
  if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
    // * never overflows, and + overflow is desired
    price0CumulativeLast +=
      uint256(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) *
      timeElapsed;
    price1CumulativeLast +=
      uint256(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) *
      timeElapsed;
  }
  reserve0 = uint112(balance0);
  reserve1 = uint112(balance1);
  blockTimestampLast = blockTimestamp;
  emit Sync(reserve0, reserve1);
}

internal UniswapV2Pair._mintFee

Parameters

Name	Type
_reserve0	uint112
_reserve1	uint112

Properties

Visibility private

Mutability transaction

Source Code

function _mintFee(uint112 _reserve0, uint112 _reserve1)
  private
  returns (bool feeOn)
{
  address feeTo = IUniswapV2Factory(factory).feeTo();
  feeOn = feeTo != address(0);
  uint256 _kLast = kLast; // gas savings
  if (feeOn) {
    if (_kLast != 0) {
      uint256 rootK = Math.sqrt(uint256(_reserve0).mul(_reserve1));
      uint256 rootKLast = Math.sqrt(_kLast);
      if (rootK > rootKLast) {
        uint256 numerator = totalSupply.mul(rootK.sub(rootKLast));
        uint256 denominator = rootK.mul(5).add(rootKLast);
        uint256 liquidity = numerator / denominator;
        if (liquidity > 0) _mint(feeTo, liquidity);
      }
    }
  } else if (_kLast != 0) {
    kLast = 0;
  }
}

internal UniswapV2ERC20._mint

Parameters

Name	Type
to	address
value	uint

Properties

Visibility internal

Mutability transaction

Source Code

function _mint(address to, uint256 value) internal {
  totalSupply = totalSupply.add(value);
  balanceOf[to] = balanceOf[to].add(value);
  emit Transfer(address(0), to, value);
}

internal UniswapV2ERC20._burn

Parameters

Name	Type
from	address
value	uint

Properties

Visibility internal

Mutability transaction

Source Code

function _burn(address from, uint256 value) internal {
  balanceOf[from] = balanceOf[from].sub(value);
  totalSupply = totalSupply.sub(value);
  emit Transfer(from, address(0), value);
}

internal UniswapV2ERC20._approve

Parameters

Name	Type
owner	address
spender	address
value	uint

Properties

Visibility private

Mutability transaction

Source Code

function _approve(
  address owner,
  address spender,
  uint256 value
) private {
  allowance[owner][spender] = value;
  emit Approval(owner, spender, value);
}

internal UniswapV2ERC20._transfer

Parameters

Name	Type
from	address
to	address
value	uint

Properties

Visibility private

Mutability transaction

Source Code

function _transfer(
  address from,
  address to,
  uint256 value
) private {
  balanceOf[from] = balanceOf[from].sub(value);
  balanceOf[to] = balanceOf[to].add(value);
  emit Transfer(from, to, value);
}

Uniswap V2

ERC20

About

Stats

Library Use

Events (6) keyboard_arrow_up

Approval Event

Parameters help Event parameters list the data that an event contains.

Burn Event

Parameters help Event parameters list the data that an event contains.

Mint Event

Parameters help Event parameters list the data that an event contains.

Swap Event

Parameters help Event parameters list the data that an event contains.

Sync Event

Parameters help Event parameters list the data that an event contains.

Transfer Event

Parameters help Event parameters list the data that an event contains.

Constants (6) keyboard_arrow_up

MINIMUM_LIQUIDITY Constant

SELECTOR Constant

name Constant

symbol Constant

decimals Constant

PERMIT_TYPEHASH Constant

State Variables (15) keyboard_arrow_up

factory Variable

token0 Variable

token1 Variable

price0CumulativeLast Variable

price1CumulativeLast Variable

kLast Variable

totalSupply Variable

DOMAIN_SEPARATOR Variable

balanceOf Variable

nonces Variable

reserve0 Variable

reserve1 Variable

blockTimestampLast Variable

unlocked Variable

allowance Variable

Functions Expand All Collapse All

approve keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Source Code

transfer keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Source Code

transferFrom keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Source Code

permit keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Requirements help Requirements are checks that the function makes when it runs, and give you insight on what conditions are required for the function to succeed.

Source Code

getReserves keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Source Code

initialize keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Requirements help Requirements are checks that the function makes when it runs, and give you insight on what conditions are required for the function to succeed.

Source Code

mint keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Modifiers help Modifiers are additions to a function that typically make various checks before the function is run.

lock checks for the following:

Requirements help Requirements are checks that the function makes when it runs, and give you insight on what conditions are required for the function to succeed.

Source Code

burn keyboard_arrow_up

Parameters help Function parameters list what input the function expects from the user. Each parameter must be given a value.

Properties

Modifiers help Modifiers are additions to a function that typically make various checks before the function is run.

lock checks for the following:

Events (6)

Parameters

Parameters

Parameters

Parameters

Parameters

Parameters

Constants (6)

State Variables (15)

approve

Parameters

transfer

Parameters

transferFrom

Parameters

permit

Parameters

Requirements

getReserves

Parameters

initialize

Parameters

Requirements

mint

Parameters

Modifiers

Requirements

burn

Parameters

Modifiers

Requirements

swap

Parameters

Modifiers

Requirements

skim

Parameters

Modifiers

Requirements

sync

Parameters

Modifiers

Requirements

internal UniswapV2Pair._safeTransfer

Parameters

Requirements

internal UniswapV2Pair._update

Parameters

Requirements

internal UniswapV2Pair._mintFee

Parameters

internal UniswapV2ERC20._mint

Parameters

internal UniswapV2ERC20._burn

Parameters

internal UniswapV2ERC20._approve

Parameters

internal UniswapV2ERC20._transfer

Parameters