# QuoterV2

Allows getting the expected amount out or amount in for a given swap without executing the swap

*These functions are not gas efficient and should not be called on chain. Instead, optimistically execute the swap and check the amounts in the callback.*

### State Variables <a href="#state-variables" id="state-variables"></a>

#### amountOutCached <a href="#amountoutcached" id="amountoutcached"></a>

*Transient storage variable used to check a safety condition in exact output swaps.*

```solidity
uint256 private amountOutCached;
```

### Functions <a href="#functions" id="functions"></a>

#### constructor <a href="#constructor" id="constructor"></a>

```solidity
constructor(address _factory, address _WSEI) PeripheryImmutableState(_factory, _WSEI);
```

#### getPool <a href="#getpool" id="getpool"></a>

```solidity
function getPool(address tokenA, address tokenB, uint24 fee) private view returns (IDragonswapV2Pool);
```

#### dragonswapV2SwapCallback <a href="#dragonswapv2swapcallback" id="dragonswapv2swapcallback"></a>

Called to `msg.sender` after executing a swap via IDragonswapV2Pool#swap.

*In the implementation you must pay the pool tokens owed for the swap. The caller of this method must be checked to be a DragonswapV2Pool deployed by the canonical DragonswapV2Factory. amount0Delta and amount1Delta can both be 0 if no tokens were swapped.*

```solidity
function dragonswapV2SwapCallback(int256 amount0Delta, int256 amount1Delta, bytes memory path) external view override;
```

**Parameters**

| Name           | Type     | Description                                                                                                                                                                             |
| -------------- | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `amount0Delta` | `int256` | The amount of token0 that was sent (negative) or must be received (positive) by the pool by the end of the swap. If positive, the callback must send that amount of token0 to the pool. |
| `amount1Delta` | `int256` | The amount of token1 that was sent (negative) or must be received (positive) by the pool by the end of the swap. If positive, the callback must send that amount of token1 to the pool. |
| `path`         | `bytes`  |                                                                                                                                                                                         |

#### parseRevertReason <a href="#parserevertreason" id="parserevertreason"></a>

*Parses a revert reason that should contain the numeric quote*

```solidity
function parseRevertReason(bytes memory reason)
    private
    pure
    returns (uint256 amount, uint160 sqrtPriceX96After, int24 tickAfter);
```

#### handleRevert <a href="#handlerevert" id="handlerevert"></a>

```solidity
function handleRevert(bytes memory reason, IDragonswapV2Pool pool, uint256 gasEstimate)
    private
    view
    returns (uint256 amount, uint160 sqrtPriceX96After, uint32 initializedTicksCrossed, uint256);
```

#### quoteExactInputSingle <a href="#quoteexactinputsingle" id="quoteexactinputsingle"></a>

```solidity
function quoteExactInputSingle(QuoteExactInputSingleParams memory params)
    public
    override
    returns (uint256 amountOut, uint160 sqrtPriceX96After, uint32 initializedTicksCrossed, uint256 gasEstimate);
```

#### quoteExactInput <a href="#quoteexactinput" id="quoteexactinput"></a>

```solidity
function quoteExactInput(bytes memory path, uint256 amountIn)
    public
    override
    returns (
        uint256 amountOut,
        uint160[] memory sqrtPriceX96AfterList,
        uint32[] memory initializedTicksCrossedList,
        uint256 gasEstimate
    );
```

#### quoteExactOutputSingle <a href="#quoteexactoutputsingle" id="quoteexactoutputsingle"></a>

```solidity
function quoteExactOutputSingle(QuoteExactOutputSingleParams memory params)
    public
    override
    returns (uint256 amountIn, uint160 sqrtPriceX96After, uint32 initializedTicksCrossed, uint256 gasEstimate);
```

#### quoteExactOutput <a href="#quoteexactoutput" id="quoteexactoutput"></a>

```solidity
function quoteExactOutput(bytes memory path, uint256 amountOut)
    public
    override
    returns (
        uint256 amountIn,
        uint160[] memory sqrtPriceX96AfterList,
        uint32[] memory initializedTicksCrossedList,
        uint256 gasEstimate
    );
```