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author | Brandon Millman <brandon.millman@gmail.com> | 2018-08-03 02:21:05 +0800 |
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committer | Brandon Millman <brandon.millman@gmail.com> | 2018-08-06 06:33:52 +0800 |
commit | d9933237a0be069d84944e4d4f1b3dffe6bb7643 (patch) | |
tree | 2bfdefb6c66a7b4ff42880bd70102d64eb242e02 /packages/order-utils/src/market_utils.ts | |
parent | a016747c36e0bc2c182e3d2b565ca63fb95e2b1b (diff) | |
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Move helper functions into order-utils
Diffstat (limited to 'packages/order-utils/src/market_utils.ts')
-rw-r--r-- | packages/order-utils/src/market_utils.ts | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/packages/order-utils/src/market_utils.ts b/packages/order-utils/src/market_utils.ts new file mode 100644 index 000000000..4ddcc6ec8 --- /dev/null +++ b/packages/order-utils/src/market_utils.ts @@ -0,0 +1,109 @@ +import { schemas } from '@0xproject/json-schemas'; +import { OrderRelevantState, SignedOrder } from '@0xproject/types'; +import { BigNumber } from '@0xproject/utils'; +import * as _ from 'lodash'; + +import { assert } from './assert'; +import { constants } from './constants'; + +export const marketUtils = { + /** + * Takes an array of orders and returns a subset of those orders that has enough makerAssetAmount (taking into account on-chain balances, + * allowances, and partial fills) in order to fill the input makerAssetFillAmount plus slippageBufferAmount. Iterates from first order to last. + * Sort the input by ascending rate in order to get the subset of orders that will cost the least ETH. + * @param signedOrders An array of objects that conform to the SignedOrder interface. All orders should specify the same makerAsset. + * All orders should specify WETH as the takerAsset. + * @param orderStates An array of objects corresponding to the signedOrders parameter that each contain on-chain state + * relevant to that order. + * @param makerAssetFillAmount The amount of makerAsset desired to be filled. + * @param slippageBufferAmount An additional amount makerAsset to be covered by the result in case of trade collisions or partial fills. + * @return Resulting orders and remaining fill amount that could not be covered by the input. + */ + findOrdersThatCoverMakerAssetFillAmount( + signedOrders: SignedOrder[], + orderStates: OrderRelevantState[], + makerAssetFillAmount: BigNumber, + slippageBufferAmount: BigNumber = constants.ZERO_AMOUNT, + ): { resultOrders: SignedOrder[]; remainingFillAmount: BigNumber } { + // type assertions + assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema); + assert.isBigNumber('makerAssetFillAmount', makerAssetFillAmount); + assert.isBigNumber('slippageBufferAmount', slippageBufferAmount); + // calculate total amount of makerAsset needed to be filled + const totalFillAmount = makerAssetFillAmount.plus(slippageBufferAmount); + // iterate through the signedOrders input from left to right until we have enough makerAsset to fill totalFillAmount + const result = _.reduce( + signedOrders, + ({ resultOrders, remainingFillAmount }, order, index) => { + if (remainingFillAmount.lessThanOrEqualTo(constants.ZERO_AMOUNT)) { + return { resultOrders, remainingFillAmount: constants.ZERO_AMOUNT }; + } else { + const orderState = orderStates[index]; + const makerAssetAmountAvailable = getMakerAssetAmountAvailable(orderState); + return { + resultOrders: _.concat(resultOrders, order), + remainingFillAmount: remainingFillAmount.minus(makerAssetAmountAvailable), + }; + } + }, + { resultOrders: [] as SignedOrder[], remainingFillAmount: totalFillAmount }, + ); + return result; + }, + /** + * Takes an array of orders and an array of feeOrders. Returns a subset of the feeOrders that has enough ZRX (taking into account + * on-chain balances, allowances, and partial fills) in order to fill the takerFees required by signedOrders plus a + * slippageBufferAmount. Iterates from first feeOrder to last. Sort the feeOrders by ascending rate in order to get the subset of + * feeOrders that will cost the least ETH. + * @param signedOrders An array of objects that conform to the SignedOrder interface. All orders should specify ZRX as + * the makerAsset and WETH as the takerAsset. + * @param orderStates An array of objects corresponding to the signedOrders parameter that each contain on-chain state + * relevant to that order. + * @param signedFeeOrders An array of objects that conform to the SignedOrder interface. All orders should specify ZRX as + * the makerAsset and WETH as the takerAsset. + * @param feeOrderStates An array of objects corresponding to the signedOrders parameter that each contain on-chain state + * relevant to that order. + * @param makerAssetFillAmount The amount of makerAsset desired to be filled. + * @param slippageBufferAmount An additional amount makerAsset to be covered by the result in case of trade collisions or partial fills. + * @return Resulting orders and remaining fill amount that could not be covered by the input. + */ + findFeeOrdersThatCoverFeesForTargetOrders( + signedOrders: SignedOrder[], + orderStates: OrderRelevantState[], + signedFeeOrders: SignedOrder[], + feeOrderStates: OrderRelevantState[], + slippageBufferAmount: BigNumber = constants.ZERO_AMOUNT, + ): { resultOrders: SignedOrder[]; remainingFillAmount: BigNumber } { + // type assertions + assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema); + assert.doesConformToSchema('signedFeeOrders', signedFeeOrders, schemas.signedOrdersSchema); + assert.isBigNumber('slippageBufferAmount', slippageBufferAmount); + // calculate total amount of ZRX needed to fill signedOrders + const totalFeeAmount = _.reduce( + signedOrders, + (accFees, order, index) => { + const orderState = orderStates[index]; + const makerAssetAmountAvailable = getMakerAssetAmountAvailable(orderState); + const feeToFillMakerAssetAmountAvailable = makerAssetAmountAvailable + .div(order.makerAssetAmount) + .mul(order.takerFee); + return accFees.plus(feeToFillMakerAssetAmountAvailable); + }, + constants.ZERO_AMOUNT, + ); + return marketUtils.findOrdersThatCoverMakerAssetFillAmount( + signedFeeOrders, + feeOrderStates, + totalFeeAmount, + slippageBufferAmount, + ); + }, +}; + +const getMakerAssetAmountAvailable = (orderState: OrderRelevantState) => { + return BigNumber.min( + orderState.makerBalance, + orderState.remainingFillableMakerAssetAmount, + orderState.makerProxyAllowance, + ); +}; |