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import digest from '../runtime/digest.ts'
export const encoder = new TextEncoder()export const decoder = new TextDecoder()
const MAX_INT32 = 2 ** 32
export function concat(...buffers: Uint8Array[]): Uint8Array {  const size = buffers.reduce((acc, { length }) => acc + length, 0)  const buf = new Uint8Array(size)  let i = 0  buffers.forEach((buffer) => {    buf.set(buffer, i)    i += buffer.length  })  return buf}
export function p2s(alg: string, p2sInput: Uint8Array) {  return concat(encoder.encode(alg), new Uint8Array([0]), p2sInput)}
function writeUInt32BE(buf: Uint8Array, value: number, offset?: number) {  if (value < 0 || value >= MAX_INT32) {    throw new RangeError(`value must be >= 0 and <= ${MAX_INT32 - 1}. Received ${value}`)  }  buf.set([value >>> 24, value >>> 16, value >>> 8, value & 0xff], offset)}
export function uint64be(value: number) {  const high = Math.floor(value / MAX_INT32)  const low = value % MAX_INT32  const buf = new Uint8Array(8)  writeUInt32BE(buf, high, 0)  writeUInt32BE(buf, low, 4)  return buf}
export function uint32be(value: number) {  const buf = new Uint8Array(4)  writeUInt32BE(buf, value)  return buf}
export function lengthAndInput(input: Uint8Array) {  return concat(uint32be(input.length), input)}
export async function concatKdf(secret: Uint8Array, bits: number, value: Uint8Array) {  const iterations = Math.ceil((bits >> 3) / 32)  const res = new Uint8Array(iterations * 32)  for (let iter = 0; iter < iterations; iter++) {    const buf = new Uint8Array(4 + secret.length + value.length)    buf.set(uint32be(iter + 1))    buf.set(secret, 4)    buf.set(value, 4 + secret.length)    res.set(await digest('sha256', buf), iter * 32)  }  return res.slice(0, bits >> 3)}