12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Returns the index of the last occurrence of the needle array in the source * array, or -1 if it is not present. * * The complexity of this function is `O(source.length * needle.length)`. * * @param source Source array to check. * @param needle Needle array to check for. * @param start Start index in the source array to begin the search. Defaults to * the end of the array. * @returns Index of the last occurrence of the needle array in the source * array, or -1 if it is not present. * * @example Basic usage * ```ts * import { lastIndexOfNeedle } from "https://deno.land/std@$STD_VERSION/bytes/last_index_of_needle.ts"; * * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]); * const needle = new Uint8Array([1, 2]); * const notNeedle = new Uint8Array([5, 0]); * * lastIndexOfNeedle(source, needle); // 5 * lastIndexOfNeedle(source, notNeedle); // -1 * ``` * * @example Start index * ```ts * import { lastIndexOfNeedle } from "https://deno.land/std@$STD_VERSION/bytes/last_index_of_needle.ts"; * * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]); * const needle = new Uint8Array([1, 2]); * * lastIndexOfNeedle(source, needle, 2); // 1 * lastIndexOfNeedle(source, needle, 6); // 3 * ``` * Defining a start index will begin the search at the specified index in the * source array. */export function lastIndexOfNeedle(  source: Uint8Array,  needle: Uint8Array,  start: number = source.length - 1,): number {  if (start < 0) {    return -1;  }  if (start >= source.length) {    start = source.length - 1;  }  const e = needle[needle.length - 1];  for (let i = start; i >= 0; i--) {    if (source[i] !== e) continue;    let matched = 1;    let j = i;    while (      matched < needle.length &&      source[--j] === needle[needle.length - 1 - (i - j)]    ) {      matched++;    }    if (matched === needle.length) {      return i - needle.length + 1;    }  }  return -1;}