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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
/** Supporting functions for media_types that do not make part of the public * API. * * @module * @private */
export function consumeToken(v: string): [token: string, rest: string] {  const notPos = indexOf(v, isNotTokenChar);  if (notPos == -1) {    return [v, ""];  }  if (notPos == 0) {    return ["", v];  }  return [v.slice(0, notPos), v.slice(notPos)];}
export function consumeValue(v: string): [value: string, rest: string] {  if (!v) {    return ["", v];  }  if (v[0] !== `"`) {    return consumeToken(v);  }  let value = "";  for (let i = 1; i < v.length; i++) {    const r = v[i];    if (r === `"`) {      return [value, v.slice(i + 1)];    }    if (r === "\\" && i + 1 < v.length && isTSpecial(v[i + 1])) {      value += v[i + 1];      i++;      continue;    }    if (r === "\r" || r === "\n") {      return ["", v];    }    value += v[i];  }  return ["", v];}
export function consumeMediaParam(  v: string,): [key: string, value: string, rest: string] {  let rest = v.trimStart();  if (!rest.startsWith(";")) {    return ["", "", v];  }  rest = rest.slice(1);  rest = rest.trimStart();  let param: string;  [param, rest] = consumeToken(rest);  param = param.toLowerCase();  if (!param) {    return ["", "", v];  }  rest = rest.slice(1);  rest = rest.trimStart();  const [value, rest2] = consumeValue(rest);  if (value == "" && rest2 === rest) {    return ["", "", v];  }  rest = rest2;  return [param, value, rest];}
export function decode2331Encoding(v: string): string | undefined {  const sv = v.split(`'`, 3);  if (sv.length !== 3) {    return undefined;  }  const charset = sv[0].toLowerCase();  if (!charset) {    return undefined;  }  if (charset != "us-ascii" && charset != "utf-8") {    return undefined;  }  const encv = decodeURI(sv[2]);  if (!encv) {    return undefined;  }  return encv;}
function indexOf<T>(s: Iterable<T>, fn: (s: T) => boolean): number {  let i = -1;  for (const v of s) {    i++;    if (fn(v)) {      return i;    }  }  return -1;}
export function isIterator<T>(obj: unknown): obj is Iterable<T> {  if (obj == null) {    return false;  }  // deno-lint-ignore no-explicit-any  return typeof (obj as any)[Symbol.iterator] === "function";}
export function isToken(s: string): boolean {  if (!s) {    return false;  }  return indexOf(s, isNotTokenChar) < 0;}
function isNotTokenChar(r: string): boolean {  return !isTokenChar(r);}
function isTokenChar(r: string): boolean {  const code = r.charCodeAt(0);  return code > 0x20 && code < 0x7f && !isTSpecial(r);}
function isTSpecial(r: string): boolean {  return `()<>@,;:\\"/[]?=`.includes(r[0]);}
const CHAR_CODE_SPACE = " ".charCodeAt(0);const CHAR_CODE_TILDE = "~".charCodeAt(0);
export function needsEncoding(s: string): boolean {  for (const b of s) {    const charCode = b.charCodeAt(0);    if (      (charCode < CHAR_CODE_SPACE || charCode > CHAR_CODE_TILDE) && b !== "\t"    ) {      return true;    }  }  return false;}