import * as BigNumber from 'bignumber.js'; import * as BN from 'bn.js'; import * as ethUtil from 'ethereumjs-util'; import * as ethABI from 'ethereumjs-abi'; import * as _ from 'lodash'; import {constants} from './utils/constants'; import {assert} from './utils/assert'; import {ECSignatureSchema} from './schemas/ec_signature_schema'; import {SolidityTypes} from './types'; /** * Elliptic Curve signature */ export interface ECSignature { v: number; r: string; s: string; } const MAX_DIGITS_IN_UNSIGNED_256_INT = 78; export class ZeroEx { /** * Computes the orderHash given the order parameters and returns it as a hex encoded string. */ public static getOrderHashHex(exchangeContractAddr: string, makerAddr: string, takerAddr: string, tokenMAddress: string, tokenTAddress: string, feeRecipient: string, valueM: BigNumber.BigNumber, valueT: BigNumber.BigNumber, makerFee: BigNumber.BigNumber, takerFee: BigNumber.BigNumber, expiration: BigNumber.BigNumber, salt: BigNumber.BigNumber): string { takerAddr = _.isEmpty(takerAddr) ? constants.NULL_ADDRESS : takerAddr ; assert.isETHAddressHex('exchangeContractAddr', exchangeContractAddr); assert.isETHAddressHex('makerAddr', makerAddr); assert.isETHAddressHex('takerAddr', takerAddr); assert.isETHAddressHex('tokenMAddress', tokenMAddress); assert.isETHAddressHex('tokenTAddress', tokenTAddress); assert.isETHAddressHex('feeRecipient', feeRecipient); assert.isBigNumber('valueM', valueM); assert.isBigNumber('valueT', valueT); assert.isBigNumber('makerFee', makerFee); assert.isBigNumber('takerFee', takerFee); assert.isBigNumber('expiration', expiration); assert.isBigNumber('salt', salt); const orderParts = [ {value: exchangeContractAddr, type: SolidityTypes.address}, {value: makerAddr, type: SolidityTypes.address}, {value: takerAddr, type: SolidityTypes.address}, {value: tokenMAddress, type: SolidityTypes.address}, {value: tokenTAddress, type: SolidityTypes.address}, {value: feeRecipient, type: SolidityTypes.address}, {value: this.bigNumberToBN(valueM), type: SolidityTypes.uint256}, {value: this.bigNumberToBN(valueT), type: SolidityTypes.uint256}, {value: this.bigNumberToBN(makerFee), type: SolidityTypes.uint256}, {value: this.bigNumberToBN(takerFee), type: SolidityTypes.uint256}, {value: this.bigNumberToBN(expiration), type: SolidityTypes.uint256}, {value: this.bigNumberToBN(salt), type: SolidityTypes.uint256}, ]; const types = _.map(orderParts, o => o.type); const values = _.map(orderParts, o => o.value); const hashBuff = ethABI.soliditySHA3(types, values); const hashHex = ethUtil.bufferToHex(hashBuff); return hashHex; } /** * Verifies that the elliptic curve signature `signature` was generated * by signing `data` with the private key corresponding to the `signerAddressHex` address. */ public static isValidSignature(dataHex: string, signature: ECSignature, signerAddressHex: string): boolean { assert.isHexString('dataHex', dataHex); assert.doesConformToSchema('signature', signature, ECSignatureSchema); assert.isETHAddressHex('signerAddressHex', signerAddressHex); const dataBuff = ethUtil.toBuffer(dataHex); const msgHashBuff = ethUtil.hashPersonalMessage(dataBuff); try { const pubKey = ethUtil.ecrecover(msgHashBuff, signature.v, ethUtil.toBuffer(signature.r), ethUtil.toBuffer(signature.s)); const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey)); return retrievedAddress === signerAddressHex; } catch (err) { return false; } } /** * Generates pseudo-random 256 bit salt. * The salt is used to ensure that the 0x order generated has a unique orderHash that does * not collide with any other outstanding orders. */ public static generatePseudoRandomSalt(): BigNumber.BigNumber { // BigNumber.random returns a pseudo-random number between 0 & 1 with a passed in number of decimal places. // Source: https://mikemcl.github.io/bignumber.js/#random const randomNumber = BigNumber.random(MAX_DIGITS_IN_UNSIGNED_256_INT); const factor = new BigNumber(10).pow(MAX_DIGITS_IN_UNSIGNED_256_INT - 1); const salt = randomNumber.times(factor).round(); return salt; } /** Checks if order hash is valid */ public static isValidOrderHash(orderHash: string): boolean { assert.isString('orderHash', orderHash); const isValid = /^0x[0-9A-F]{64}$/i.test(orderHash); return isValid; } /* * A unit amount is defined as the amount of a token above the specified decimal places (integer part). * E.g: If a currency has 18 decimal places, 1e18 or one quintillion of the currency is equivalent * to 1 unit. */ public static toUnitAmount(amount: BigNumber.BigNumber, decimals: number): BigNumber.BigNumber { assert.isBigNumber('amount', amount); assert.isNumber('decimals', decimals); const aUnit = new BigNumber(10).pow(decimals); const unit = amount.div(aUnit); return unit; } /* * A baseUnit is defined as the smallest denomination of a token. An amount expressed in baseUnits * is the amount expressed in the smallest denomination. * E.g: 1 unit of a token with 18 decimal places is expressed in baseUnits as 1000000000000000000 */ public static toBaseUnitAmount(amount: BigNumber.BigNumber, decimals: number): BigNumber.BigNumber { assert.isBigNumber('amount', amount); assert.isNumber('decimals', decimals); const unit = new BigNumber(10).pow(decimals); const baseUnitAmount = amount.times(unit); return baseUnitAmount; } /** * Converts BigNumber instance to BN * The only we convert to BN is to remain compatible with `ethABI. soliditySHA3 ` that * expects values of Solidity type `uint` to be of type `BN`. * We do not use BN anywhere else in the codebase. */ private static bigNumberToBN(value: BigNumber.BigNumber) { return new BN(value.toString(), 10); } }