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import { encode, decode, hmac } from "../deps.ts";import { date } from "../util.ts";
/** Some magic bytes. */const AWS4: Uint8Array = encode("AWS4", "utf8");
/** Creates a HMAC-SHA256 mac.*/export function awsSignatureV4(  key: Uint8Array,  msg: Uint8Array,  outputEncoding?: string,): string | Uint8Array {  return hmac("sha256", key, msg, undefined, outputEncoding);}
/** Creates a key for generating an aws signature version 4. */export function kdf(  key: string | Uint8Array,  dateStamp: Date | string,  region: string,  service: string,  keyInputEncoding?: string,  outputEncoding?: string,): string | Uint8Array {  if (typeof key === "string") {    key = encode(key, keyInputEncoding) as Uint8Array;  }
  if (typeof dateStamp !== "string") {    dateStamp = date.format(dateStamp, "dateStamp");  } else if (!date.DATE_STAMP_REGEX.test(dateStamp)) {    throw new TypeError("date stamp format must be yyyymmdd");  }
  const paddedKey: Uint8Array = new Uint8Array(4 + key.byteLength);
  paddedKey.set(AWS4, 0);  paddedKey.set(key, 4);
  let mac: Uint8Array = hmac(    "sha256",    paddedKey,    dateStamp as string,    "utf8",  ) as Uint8Array;
  mac = hmac("sha256", mac, region, "utf8") as Uint8Array;
  mac = hmac("sha256", mac, service, "utf8") as Uint8Array;
  mac = hmac("sha256", mac, "aws4_request", "utf8") as Uint8Array;
  return outputEncoding ? decode(mac, outputEncoding) : mac;}