63 lines
1.9 KiB
TypeScript
63 lines
1.9 KiB
TypeScript
import { BigNumber } from '@0x/utils';
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import * as crypto from 'crypto';
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import * as ethUtil from 'ethereumjs-util';
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import { constants } from './constants';
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const { WORD_LENGTH } = constants;
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const WORD_CEIL = new BigNumber(2).pow(WORD_LENGTH * 8);
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/**
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* Concatenate all arguments as a hex string.
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*/
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export function hexConcat(...args: Array<string | number | Buffer>): string {
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return ethUtil.bufferToHex(Buffer.concat(args.map(h => ethUtil.toBuffer(h))));
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}
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/**
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* Generate a random hex string.
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*/
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export function hexRandom(size: number = WORD_LENGTH): string {
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return ethUtil.bufferToHex(crypto.randomBytes(size));
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}
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/**
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* Left-pad a hex number to a number of bytes.
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*/
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export function hexLeftPad(n: string | BigNumber | number, size: number = WORD_LENGTH): string {
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return ethUtil.bufferToHex(ethUtil.setLengthLeft(toHex(n), size));
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}
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/**
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* Right-pad a hex number to a number of bytes.
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*/
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export function hexRightPad(n: string | BigNumber | number, size: number = WORD_LENGTH): string {
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return ethUtil.bufferToHex(ethUtil.setLengthRight(toHex(n), size));
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}
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/**
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* Inverts a hex word.
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*/
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export function hexInvert(n: string | BigNumber | number, size: number = WORD_LENGTH): string {
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const buf = ethUtil.setLengthLeft(toHex(n), size);
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// tslint:disable-next-line: no-bitwise
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return ethUtil.bufferToHex(Buffer.from(buf.map(b => ~b)));
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}
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/**
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* Convert a string, a number, or a BigNumber into a hex string.
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* Works with negative numbers, as well.
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*/
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export function toHex(n: string | BigNumber | number, size: number = WORD_LENGTH): string {
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if (typeof n === 'string' && /^0x[0-9a-f]+$/i.test(n)) {
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// Already a hex.
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return n;
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}
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let _n = new BigNumber(n);
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if (_n.isNegative()) {
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// Perform two's-complement.
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_n = new BigNumber(hexInvert(toHex(_n.abs()), size).substr(2), 16).plus(1).mod(WORD_CEIL);
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}
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return `0x${_n.toString(16)}`;
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}
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