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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.import { copyBytes } from "../io/util.ts";
/** Find first index of binary pattern from a. If not found, then return -1 **/export function findIndex(a: Uint8Array, pat: Uint8Array): number {  const s = pat[0];  for (let i = 0; i < a.length; i++) {    if (a[i] !== s) continue;    const pin = i;    let matched = 1;    let j = i;    while (matched < pat.length) {      j++;      if (a[j] !== pat[j - pin]) {        break;      }      matched++;    }    if (matched === pat.length) {      return pin;    }  }  return -1;}
/** Find last index of binary pattern from a. If not found, then return -1 **/export function findLastIndex(a: Uint8Array, pat: Uint8Array): number {  const e = pat[pat.length - 1];  for (let i = a.length - 1; i >= 0; i--) {    if (a[i] !== e) continue;    const pin = i;    let matched = 1;    let j = i;    while (matched < pat.length) {      j--;      if (a[j] !== pat[pat.length - 1 - (pin - j)]) {        break;      }      matched++;    }    if (matched === pat.length) {      return pin - pat.length + 1;    }  }  return -1;}
/** Check whether binary arrays are equal to each other **/export function equal(a: Uint8Array, match: Uint8Array): boolean {  if (a.length !== match.length) return false;  for (let i = 0; i < match.length; i++) {    if (a[i] !== match[i]) return false;  }  return true;}
/** Check whether binary array has binary prefix  **/export function hasPrefix(a: Uint8Array, prefix: Uint8Array): boolean {  for (let i = 0, max = prefix.length; i < max; i++) {    if (a[i] !== prefix[i]) return false;  }  return true;}
/** * Repeat bytes. returns a new byte slice consisting of `count` copies of `b`. * @param b The origin bytes * @param count The count you want to repeat. */export function repeat(b: Uint8Array, count: number): Uint8Array {  if (count === 0) {    return new Uint8Array();  }
  if (count < 0) {    throw new Error("bytes: negative repeat count");  } else if ((b.length * count) / count !== b.length) {    throw new Error("bytes: repeat count causes overflow");  }
  const int = Math.floor(count);
  if (int !== count) {    throw new Error("bytes: repeat count must be an integer");  }
  const nb = new Uint8Array(b.length * count);
  let bp = copyBytes(nb, b);
  for (; bp < nb.length; bp *= 2) {    copyBytes(nb, nb.slice(0, bp), bp);  }
  return nb;}
/** Concatenate two binary arrays and return new one  */export function concat(a: Uint8Array, b: Uint8Array): Uint8Array {  const output = new Uint8Array(a.length + b.length);  output.set(a, 0);  output.set(b, a.length);  return output;}