import { assertIsArray, assertIsBuffer, assertIsHexString } from './helpers'
import { isHexPrefixed, isHexString, padToEven, stripHexPrefix } from './internal'
import type {
NestedBufferArray,
NestedUint8Array,
PrefixedHexString,
TransformableToArray,
TransformableToBuffer,
} from './types'
/**
* Converts a `Number` into a hex `String`
* @param {Number} i
* @return {String}
*/
export const intToHex = function (i: number) {
if (!Number.isSafeInteger(i) || i < 0) {
throw new Error(`Received an invalid integer type: ${i}`)
}
return `0x${i.toString(16)}`
}
/**
* Converts an `Number` to a `Buffer`
* @param {Number} i
* @return {Buffer}
*/
export const intToBuffer = function (i: number) {
const hex = intToHex(i)
return Buffer.from(padToEven(hex.slice(2)), 'hex')
}
/**
* Returns a buffer filled with 0s.
* @param bytes the number of bytes the buffer should be
*/
export const zeros = function (bytes: number): Buffer {
return Buffer.allocUnsafe(bytes).fill(0)
}
/**
* Pads a `Buffer` with zeros till it has `length` bytes.
* Truncates the beginning or end of input if its length exceeds `length`.
* @param msg the value to pad (Buffer)
* @param length the number of bytes the output should be
* @param right whether to start padding form the left or right
* @return (Buffer)
*/
const setLength = function (msg: Buffer, length: number, right: boolean) {
const buf = zeros(length)
if (right) {
if (msg.length < length) {
msg.copy(buf)
return buf
}
return msg.slice(0, length)
} else {
if (msg.length < length) {
msg.copy(buf, length - msg.length)
return buf
}
return msg.slice(-length)
}
}
/**
* Left Pads a `Buffer` with leading zeros till it has `length` bytes.
* Or it truncates the beginning if it exceeds.
* @param msg the value to pad (Buffer)
* @param length the number of bytes the output should be
* @return (Buffer)
*/
export const setLengthLeft = function (msg: Buffer, length: number) {
assertIsBuffer(msg)
return setLength(msg, length, false)
}
/**
* Right Pads a `Buffer` with trailing zeros till it has `length` bytes.
* it truncates the end if it exceeds.
* @param msg the value to pad (Buffer)
* @param length the number of bytes the output should be
* @return (Buffer)
*/
export const setLengthRight = function (msg: Buffer, length: number) {
assertIsBuffer(msg)
return setLength(msg, length, true)
}
/**
* Trims leading zeros from a `Buffer`, `String` or `Number[]`.
* @param a (Buffer|Array|String)
* @return (Buffer|Array|String)
*/
const stripZeros = function (a: any): Buffer | number[] | string {
let first = a[0]
while (a.length > 0 && first.toString() === '0') {
a = a.slice(1)
first = a[0]
}
return a
}
/**
* Trims leading zeros from a `Buffer`.
* @param a (Buffer)
* @return (Buffer)
*/
export const unpadBuffer = function (a: Buffer): Buffer {
assertIsBuffer(a)
return stripZeros(a) as Buffer
}
/**
* Trims leading zeros from an `Array` (of numbers).
* @param a (number[])
* @return (number[])
*/
export const unpadArray = function (a: number[]): number[] {
assertIsArray(a)
return stripZeros(a) as number[]
}
/**
* Trims leading zeros from a hex-prefixed `String`.
* @param a (String)
* @return (String)
*/
export const unpadHexString = function (a: string): string {
assertIsHexString(a)
a = stripHexPrefix(a)
return ('0x' + stripZeros(a)) as string
}
export type ToBufferInputTypes =
| PrefixedHexString
| number
| bigint
| Buffer
| Uint8Array
| number[]
| TransformableToArray
| TransformableToBuffer
| null
| undefined
/**
* Attempts to turn a value into a `Buffer`.
* Inputs supported: `Buffer`, `String` (hex-prefixed), `Number`, null/undefined, `BigInt` and other objects
* with a `toArray()` or `toBuffer()` method.
* @param v the value
*/
export const toBuffer = function (v: ToBufferInputTypes): Buffer {
if (v === null || v === undefined) {
return Buffer.allocUnsafe(0)
}
if (Buffer.isBuffer(v)) {
return Buffer.from(v)
}
if (Array.isArray(v) || v instanceof Uint8Array) {
return Buffer.from(v as Uint8Array)
}
if (typeof v === 'string') {
if (!isHexString(v)) {
throw new Error(
`Cannot convert string to buffer. toBuffer only supports 0x-prefixed hex strings and this string was given: ${v}`
)
}
return Buffer.from(padToEven(stripHexPrefix(v)), 'hex')
}
if (typeof v === 'number') {
return intToBuffer(v)
}
if (typeof v === 'bigint') {
if (v < BigInt(0)) {
throw new Error(`Cannot convert negative bigint to buffer. Given: ${v}`)
}
let n = v.toString(16)
if (n.length % 2) n = '0' + n
return Buffer.from(n, 'hex')
}
if (v.toArray) {
// converts a BN to a Buffer
return Buffer.from(v.toArray())
}
if (v.toBuffer) {
return Buffer.from(v.toBuffer())
}
throw new Error('invalid type')
}
/**
* Converts a `Buffer` into a `0x`-prefixed hex `String`.
* @param buf `Buffer` object to convert
*/
export const bufferToHex = function (buf: Buffer): string {
buf = toBuffer(buf)
return '0x' + buf.toString('hex')
}
/**
* Converts a {@link Buffer} to a {@link bigint}
*/
export function bufferToBigInt(buf: Buffer) {
const hex = bufferToHex(buf)
if (hex === '0x') {
return BigInt(0)
}
return BigInt(hex)
}
/**
* Converts a {@link bigint} to a {@link Buffer}
*/
export function bigIntToBuffer(num: bigint) {
return toBuffer('0x' + num.toString(16))
}
/**
* Converts a `Buffer` to a `Number`.
* @param buf `Buffer` object to convert
* @throws If the input number exceeds 53 bits.
*/
export const bufferToInt = function (buf: Buffer): number {
const res = Number(bufferToBigInt(buf))
if (!Number.isSafeInteger(res)) throw new Error('Number exceeds 53 bits')
return res
}
/**
* Interprets a `Buffer` as a signed integer and returns a `BigInt`. Assumes 256-bit numbers.
* @param num Signed integer value
*/
export const fromSigned = function (num: Buffer): bigint {
return BigInt.asIntN(256, bufferToBigInt(num))
}
/**
* Converts a `BigInt` to an unsigned integer and returns it as a `Buffer`. Assumes 256-bit numbers.
* @param num
*/
export const toUnsigned = function (num: bigint): Buffer {
return bigIntToBuffer(BigInt.asUintN(256, num))
}
/**
* Adds "0x" to a given `String` if it does not already start with "0x".
*/
export const addHexPrefix = function (str: string): string {
if (typeof str !== 'string') {
return str
}
return isHexPrefixed(str) ? str : '0x' + str
}
/**
* Shortens a string or buffer's hex string representation to maxLength (default 50).
*
* Examples:
*
* Input: '657468657265756d000000000000000000000000000000000000000000000000'
* Output: '657468657265756d0000000000000000000000000000000000…'
*/
export function short(buffer: Buffer | string, maxLength: number = 50): string {
const bufferStr = Buffer.isBuffer(buffer) ? buffer.toString('hex') : buffer
if (bufferStr.length <= maxLength) {
return bufferStr
}
return bufferStr.slice(0, maxLength) + '…'
}
/**
* Returns the utf8 string representation from a hex string.
*
* Examples:
*
* Input 1: '657468657265756d000000000000000000000000000000000000000000000000'
* Input 2: '657468657265756d'
* Input 3: '000000000000000000000000000000000000000000000000657468657265756d'
*
* Output (all 3 input variants): 'ethereum'
*
* Note that this method is not intended to be used with hex strings
* representing quantities in both big endian or little endian notation.
*
* @param string Hex string, should be `0x` prefixed
* @return Utf8 string
*/
export const toUtf8 = function (hex: string): string {
const zerosRegexp = /^(00)+|(00)+$/g
hex = stripHexPrefix(hex)
if (hex.length % 2 !== 0) {
throw new Error('Invalid non-even hex string input for toUtf8() provided')
}
const bufferVal = Buffer.from(hex.replace(zerosRegexp, ''), 'hex')
return bufferVal.toString('utf8')
}
/**
* Converts a `Buffer` or `Array` to JSON.
* @param ba (Buffer|Array)
* @return (Array|String|null)
*/
export const baToJSON = function (ba: any): any {
if (Buffer.isBuffer(ba)) {
return `0x${ba.toString('hex')}`
} else if (ba instanceof Array) {
const array = []
for (let i = 0; i < ba.length; i++) {
array.push(baToJSON(ba[i]))
}
return array
}
}
/**
* Checks provided Buffers for leading zeroes and throws if found.
*
* Examples:
*
* Valid values: 0x1, 0x, 0x01, 0x1234
* Invalid values: 0x0, 0x00, 0x001, 0x0001
*
* Note: This method is useful for validating that RLP encoded integers comply with the rule that all
* integer values encoded to RLP must be in the most compact form and contain no leading zero bytes
* @param values An object containing string keys and Buffer values
* @throws if any provided value is found to have leading zero bytes
*/
export const validateNoLeadingZeroes = function (values: { [key: string]: Buffer | undefined }) {
for (const [k, v] of Object.entries(values)) {
if (v !== undefined && v.length > 0 && v[0] === 0) {
throw new Error(`${k} cannot have leading zeroes, received: ${v.toString('hex')}`)
}
}
}
/**
* Converts a {@link Uint8Array} or {@link NestedUint8Array} to {@link Buffer} or {@link NestedBufferArray}
*/
export function arrToBufArr(arr: Uint8Array): Buffer
export function arrToBufArr(arr: NestedUint8Array): NestedBufferArray
export function arrToBufArr(arr: Uint8Array | NestedUint8Array): Buffer | NestedBufferArray
export function arrToBufArr(arr: Uint8Array | NestedUint8Array): Buffer | NestedBufferArray {
if (!Array.isArray(arr)) {
return Buffer.from(arr)
}
return arr.map((a) => arrToBufArr(a))
}
/**
* Converts a {@link Buffer} or {@link NestedBufferArray} to {@link Uint8Array} or {@link NestedUint8Array}
*/
export function bufArrToArr(arr: Buffer): Uint8Array
export function bufArrToArr(arr: NestedBufferArray): NestedUint8Array
export function bufArrToArr(arr: Buffer | NestedBufferArray): Uint8Array | NestedUint8Array
export function bufArrToArr(arr: Buffer | NestedBufferArray): Uint8Array | NestedUint8Array {
if (!Array.isArray(arr)) {
return Uint8Array.from(arr ?? [])
}
return arr.map((a) => bufArrToArr(a))
}
/**
* Converts a {@link bigint} to a `0x` prefixed hex string
*/
export const bigIntToHex = (num: bigint) => {
return '0x' + num.toString(16)
}
/**
* Convert value from bigint to an unpadded Buffer
* (useful for RLP transport)
* @param value value to convert
*/
export function bigIntToUnpaddedBuffer(value: bigint): Buffer {
return unpadBuffer(bigIntToBuffer(value))
}
export function intToUnpaddedBuffer(value: number): Buffer {
return unpadBuffer(intToBuffer(value))
}