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import * as BigNumber from 'bignumber.js';
import * as ethUtil from 'ethereumjs-util';
import * as ethABI from 'ethereumjs-abi';
import * as _ from 'lodash';
import {constants} from './utils/constants';
import {utils} from './utils/utils';
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: utils.bigNumberToBN(valueM), type: SolidityTypes.uint256},
{value: utils.bigNumberToBN(valueT), type: SolidityTypes.uint256},
{value: utils.bigNumberToBN(makerFee), type: SolidityTypes.uint256},
{value: utils.bigNumberToBN(takerFee), type: SolidityTypes.uint256},
{value: utils.bigNumberToBN(expiration), type: SolidityTypes.uint256},
{value: utils.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;
}
}
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