SwapOperations

This contracts handles swaps and SwapPair management

We have a fixed swap fee of 0.3% and an additional dynamic fee, when a swap causes the price to move away from oracle price. The fee depends on how much you move the price away from oracle. We use PYTH as our Oracle for stock prices.

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Structs

struct SwapAmount {
    uint amount; // including fee
    uint fee;
}

This struct is used in getAmountsOut and getAmountsIn.

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Swap Pairs

SwapPairs can only be created by the protocol admins. To access swap pairs, we provide a list of functions, similar to Uniswap V2 Factory. For subgraph, you can track the event:

event PairCreated(address indexed token0, address indexed token1, address pair, uint);

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allPairsLength

function allPairsLength() external view returns (uint)

This function gives you the number of existing pairs.

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isPair

function isPair(address pair) external view returns (bool)

Check if a given address is a SwapPair from our protocol.

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getPair

function getPair(address token0, address token1) external view returns (address)

Returns 0x0 or the address for a SwapPair if there is a match. token0 and token1 can be exchanged.

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allPairs

function allPairs() external view returns (address[] memory)

Returns a list of all available pairs.

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Quotes

To get quotes for swap, we provide the following interfaces:

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getAmountsOut

function getAmountsOut(
    uint amountIn,
    address[] calldata path
) external view
returns (SwapAmount[] memory amounts, bool isUsablePrice);

Given the input amount amountIn and path (an array of token address for the swap route, with a minimum length of 2), you will receive a list of the output amounts after each route hop. All amounts include fixed and dynamic swap fee. isUsablePrice can be ignored as it indicates if the oracle prices are up-to-date and should always be true (because we update the oracle in regular intervals).

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getAmountsIn

function getAmountsIn(
    uint amountOut,
    address[] calldata path
) external view
returns (SwapAmount[] memory amounts, bool isUsablePrice);

Given the input amount amountOut and path (an array of token address for the swap route, with a minimum length of 2), you will receive a list of the required input amounts for each route hop. All amounts include fixed and dynamic swap fee. isUsablePrice can be ignored as it indicates if the oracle prices are up-to-date and should always be true (because we update the oracle in regular intervals).

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Swap

All our swap functions have an optional priceUpdateData parameter, to update the prices for our PYTH Oracle. As we frequently update the oracle ourself, there is no need to supply values.

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swapExactTokensForTokens

function swapExactTokensForTokens(
    uint amountIn,
    uint amountOutMin,
    address[] calldata path,
    address to,
    uint deadline,
    bytes[] memory priceUpdateData
) public payable
returns (SwapAmount[] memory amounts)

Swaps an exact amountIn of input tokens for as many output tokens as possible, along the route determined by the path. The first element of path is the input token, the last is the output token, and any intermediate elements represent intermediate pairs to trade through (if, for example, a direct pair does not exist).

• msg.sender should have already given the SwapOperations an allowance of at least amountIn on the input token.

Name	Type
amountIn	uint	The amount of input tokens to send.
amountOutMin	uint	The minimum amount of output tokens that must be received for the transaction not to revert.
path	address[] calldata	An array of token addresses. path.length must be >= 2. Pools for each consecutive pair of addresses must exist and have liquidity.
to	address	Recipient of the output tokens.
deadline	uint	Unix timestamp after which the transaction will revert.
priceUpdateData	bytes[] memory	PYTH price data. It is sufficient to not provide any data at all.
amounts	SwapAmount[] memory	All subsequent output token amounts including fees and the fee of each hop (fixed + dynamic swap fee).

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swapTokensForExactTokens

function swapTokensForExactTokens(
    uint amountOut,
    uint amountInMax,
    address[] calldata path,
    address to,
    uint deadline,
    bytes[] memory priceUpdateData
) public payable 
returns (SwapAmount[] memory amounts)

Receive an exact amountOut of output tokens for as few input tokens as possible, along the route determined by the path. The first element of path is the input token, the last is the output token, and any intermediate elements represent intermediate tokens to trade through (if, for example, a direct pair does not exist).

• msg.sender should have already given the SwapOperations an allowance of at least amountInMax on the input token.

Name	Type
amountOut	uint	The amount of output tokens to receive.
amountInMax	uint	The maximum amount of input tokens that can be required before the transaction reverts.
path	address[] calldata	An array of token addresses. path.length must be >= 2. Pools for each consecutive pair of addresses must exist and have liquidity.
to	address	Recipient of the output tokens.
deadline	uint	Unix timestamp after which the transaction will revert.
priceUpdateData	bytes[] memory	PYTH price data. It is sufficient to not provide any data at all.
amounts	SwapAmount[] memory	All subsequent output token amounts including fees and the fee of each hop (fixed + dynamic swap fee).

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