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// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.import {  bytesToUuid,  createBuffer,  stringToBytes,  uuidToBytes,} from "./_common.ts";import { Sha1 } from "../hash/sha1.ts";import { assert } from "../_util/assert.ts";
const UUID_RE =  /^[0-9a-f]{8}-[0-9a-f]{4}-[5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
/** * Validates the UUID v5. * @param id UUID value. */export function validate(id: string): boolean {  return UUID_RE.test(id);}
/** The options used for generating a v5 uuid. */export interface V5Options {  value: string | number[];  namespace: string | number[];}
/** * Generates a RFC4122 v5 UUID (SHA-1 namespace-based). * @param options Can use a namespace and value to create SHA-1 hash. * @param buf Can allow the UUID to be written in byte-form starting at the offset. * @param offset Index to start writing on the UUID bytes in buffer. */export function generate(  options: V5Options,  buf?: number[],  offset?: number,): string | number[] {  const i = (buf && offset) || 0;
  let { value, namespace } = options;  if (typeof value === "string") {    value = stringToBytes(value);  }
  if (typeof namespace === "string") {    namespace = uuidToBytes(namespace);  }
  assert(    namespace.length === 16,    "namespace must be uuid string or an Array of 16 byte values",  );
  const content = namespace.concat(value);  const bytes = new Sha1().update(createBuffer(content)).digest();
  bytes[6] = (bytes[6] & 0x0f) | 0x50;  bytes[8] = (bytes[8] & 0x3f) | 0x80;
  if (buf !== undefined) {    for (let idx = 0; idx < 16; ++idx) {      buf[i + idx] = bytes[idx];    }  }
  return buf ?? bytesToUuid(bytes);}