pdf.js/src/shared/util.js

/* Copyright 2012 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/* eslint no-var: error */

import './compatibility';
import { ReadableStream } from './streams_polyfill';

const IDENTITY_MATRIX = [1, 0, 0, 1, 0, 0];
const FONT_IDENTITY_MATRIX = [0.001, 0, 0, 0.001, 0, 0];

const NativeImageDecoding = {
  NONE: 'none',
  DECODE: 'decode',
  DISPLAY: 'display',
};

// Permission flags from Table 22, Section 7.6.3.2 of the PDF specification.
const PermissionFlag = {
  PRINT: 0x04,
  MODIFY_CONTENTS: 0x08,
  COPY: 0x10,
  MODIFY_ANNOTATIONS: 0x20,
  FILL_INTERACTIVE_FORMS: 0x100,
  COPY_FOR_ACCESSIBILITY: 0x200,
  ASSEMBLE: 0x400,
  PRINT_HIGH_QUALITY: 0x800,
};

const TextRenderingMode = {
  FILL: 0,
  STROKE: 1,
  FILL_STROKE: 2,
  INVISIBLE: 3,
  FILL_ADD_TO_PATH: 4,
  STROKE_ADD_TO_PATH: 5,
  FILL_STROKE_ADD_TO_PATH: 6,
  ADD_TO_PATH: 7,
  FILL_STROKE_MASK: 3,
  ADD_TO_PATH_FLAG: 4,
};

const ImageKind = {
  GRAYSCALE_1BPP: 1,
  RGB_24BPP: 2,
  RGBA_32BPP: 3,
};

const AnnotationType = {
  TEXT: 1,
  LINK: 2,
  FREETEXT: 3,
  LINE: 4,
  SQUARE: 5,
  CIRCLE: 6,
  POLYGON: 7,
  POLYLINE: 8,
  HIGHLIGHT: 9,
  UNDERLINE: 10,
  SQUIGGLY: 11,
  STRIKEOUT: 12,
  STAMP: 13,
  CARET: 14,
  INK: 15,
  POPUP: 16,
  FILEATTACHMENT: 17,
  SOUND: 18,
  MOVIE: 19,
  WIDGET: 20,
  SCREEN: 21,
  PRINTERMARK: 22,
  TRAPNET: 23,
  WATERMARK: 24,
  THREED: 25,
  REDACT: 26,
};

const AnnotationStateModelType = {
  MARKED: 'Marked',
  REVIEW: 'Review',
};

const AnnotationMarkedState = {
  MARKED: 'Marked',
  UNMARKED: 'Unmarked',
};

const AnnotationReviewState = {
  ACCEPTED: 'Accepted',
  REJECTED: 'Rejected',
  CANCELLED: 'Cancelled',
  COMPLETED: 'Completed',
  NONE: 'None',
};

const AnnotationReplyType = {
  GROUP: 'Group',
  REPLY: 'R',
};

const AnnotationFlag = {
  INVISIBLE: 0x01,
  HIDDEN: 0x02,
  PRINT: 0x04,
  NOZOOM: 0x08,
  NOROTATE: 0x10,
  NOVIEW: 0x20,
  READONLY: 0x40,
  LOCKED: 0x80,
  TOGGLENOVIEW: 0x100,
  LOCKEDCONTENTS: 0x200,
};

const AnnotationFieldFlag = {
  READONLY: 0x0000001,
  REQUIRED: 0x0000002,
  NOEXPORT: 0x0000004,
  MULTILINE: 0x0001000,
  PASSWORD: 0x0002000,
  NOTOGGLETOOFF: 0x0004000,
  RADIO: 0x0008000,
  PUSHBUTTON: 0x0010000,
  COMBO: 0x0020000,
  EDIT: 0x0040000,
  SORT: 0x0080000,
  FILESELECT: 0x0100000,
  MULTISELECT: 0x0200000,
  DONOTSPELLCHECK: 0x0400000,
  DONOTSCROLL: 0x0800000,
  COMB: 0x1000000,
  RICHTEXT: 0x2000000,
  RADIOSINUNISON: 0x2000000,
  COMMITONSELCHANGE: 0x4000000,
};

const AnnotationBorderStyleType = {
  SOLID: 1,
  DASHED: 2,
  BEVELED: 3,
  INSET: 4,
  UNDERLINE: 5,
};

const StreamType = {
  UNKNOWN: 'UNKNOWN',
  FLATE: 'FLATE',
  LZW: 'LZW',
  DCT: 'DCT',
  JPX: 'JPX',
  JBIG: 'JBIG',
  A85: 'A85',
  AHX: 'AHX',
  CCF: 'CCF',
  RLX: 'RLX', // PDF short name is 'RL', but telemetry requires three chars.
};

const FontType = {
  UNKNOWN: 'UNKNOWN',
  TYPE1: 'TYPE1',
  TYPE1C: 'TYPE1C',
  CIDFONTTYPE0: 'CIDFONTTYPE0',
  CIDFONTTYPE0C: 'CIDFONTTYPE0C',
  TRUETYPE: 'TRUETYPE',
  CIDFONTTYPE2: 'CIDFONTTYPE2',
  TYPE3: 'TYPE3',
  OPENTYPE: 'OPENTYPE',
  TYPE0: 'TYPE0',
  MMTYPE1: 'MMTYPE1',
};

const VerbosityLevel = {
  ERRORS: 0,
  WARNINGS: 1,
  INFOS: 5,
};

const CMapCompressionType = {
  NONE: 0,
  BINARY: 1,
  STREAM: 2,
};

// All the possible operations for an operator list.
const OPS = {
  // Intentionally start from 1 so it is easy to spot bad operators that will be
  // 0's.
  dependency: 1,
  setLineWidth: 2,
  setLineCap: 3,
  setLineJoin: 4,
  setMiterLimit: 5,
  setDash: 6,
  setRenderingIntent: 7,
  setFlatness: 8,
  setGState: 9,
  save: 10,
  restore: 11,
  transform: 12,
  moveTo: 13,
  lineTo: 14,
  curveTo: 15,
  curveTo2: 16,
  curveTo3: 17,
  closePath: 18,
  rectangle: 19,
  stroke: 20,
  closeStroke: 21,
  fill: 22,
  eoFill: 23,
  fillStroke: 24,
  eoFillStroke: 25,
  closeFillStroke: 26,
  closeEOFillStroke: 27,
  endPath: 28,
  clip: 29,
  eoClip: 30,
  beginText: 31,
  endText: 32,
  setCharSpacing: 33,
  setWordSpacing: 34,
  setHScale: 35,
  setLeading: 36,
  setFont: 37,
  setTextRenderingMode: 38,
  setTextRise: 39,
  moveText: 40,
  setLeadingMoveText: 41,
  setTextMatrix: 42,
  nextLine: 43,
  showText: 44,
  showSpacedText: 45,
  nextLineShowText: 46,
  nextLineSetSpacingShowText: 47,
  setCharWidth: 48,
  setCharWidthAndBounds: 49,
  setStrokeColorSpace: 50,
  setFillColorSpace: 51,
  setStrokeColor: 52,
  setStrokeColorN: 53,
  setFillColor: 54,
  setFillColorN: 55,
  setStrokeGray: 56,
  setFillGray: 57,
  setStrokeRGBColor: 58,
  setFillRGBColor: 59,
  setStrokeCMYKColor: 60,
  setFillCMYKColor: 61,
  shadingFill: 62,
  beginInlineImage: 63,
  beginImageData: 64,
  endInlineImage: 65,
  paintXObject: 66,
  markPoint: 67,
  markPointProps: 68,
  beginMarkedContent: 69,
  beginMarkedContentProps: 70,
  endMarkedContent: 71,
  beginCompat: 72,
  endCompat: 73,
  paintFormXObjectBegin: 74,
  paintFormXObjectEnd: 75,
  beginGroup: 76,
  endGroup: 77,
  beginAnnotations: 78,
  endAnnotations: 79,
  beginAnnotation: 80,
  endAnnotation: 81,
  paintJpegXObject: 82,
  paintImageMaskXObject: 83,
  paintImageMaskXObjectGroup: 84,
  paintImageXObject: 85,
  paintInlineImageXObject: 86,
  paintInlineImageXObjectGroup: 87,
  paintImageXObjectRepeat: 88,
  paintImageMaskXObjectRepeat: 89,
  paintSolidColorImageMask: 90,
  constructPath: 91,
};

const UNSUPPORTED_FEATURES = {
  unknown: 'unknown',
  forms: 'forms',
  javaScript: 'javaScript',
  smask: 'smask',
  shadingPattern: 'shadingPattern',
  font: 'font',
};

const PasswordResponses = {
  NEED_PASSWORD: 1,
  INCORRECT_PASSWORD: 2,
};

let verbosity = VerbosityLevel.WARNINGS;

function setVerbosityLevel(level) {
  if (Number.isInteger(level)) {
    verbosity = level;
  }
}

function getVerbosityLevel() {
  return verbosity;
}

// A notice for devs. These are good for things that are helpful to devs, such
// as warning that Workers were disabled, which is important to devs but not
// end users.
function info(msg) {
  if (verbosity >= VerbosityLevel.INFOS) {
    console.log(`Info: ${msg}`);
  }
}

// Non-fatal warnings.
function warn(msg) {
  if (verbosity >= VerbosityLevel.WARNINGS) {
    console.log(`Warning: ${msg}`);
  }
}

function unreachable(msg) {
  throw new Error(msg);
}

function assert(cond, msg) {
  if (!cond) {
    unreachable(msg);
  }
}

// Checks if URLs have the same origin. For non-HTTP based URLs, returns false.
function isSameOrigin(baseUrl, otherUrl) {
  let base;
  try {
    base = new URL(baseUrl);
    if (!base.origin || base.origin === 'null') {
      return false; // non-HTTP url
    }
  } catch (e) {
    return false;
  }

  const other = new URL(otherUrl, base);
  return base.origin === other.origin;
}

// Checks if URLs use one of the whitelisted protocols, e.g. to avoid XSS.
function _isValidProtocol(url) {
  if (!url) {
    return false;
  }
  switch (url.protocol) {
    case 'http:':
    case 'https:':
    case 'ftp:':
    case 'mailto:':
    case 'tel:':
      return true;
    default:
      return false;
  }
}

/**
 * Attempts to create a valid absolute URL.
 *
 * @param {URL|string} url - An absolute, or relative, URL.
 * @param {URL|string} baseUrl - An absolute URL.
 * @returns Either a valid {URL}, or `null` otherwise.
 */
function createValidAbsoluteUrl(url, baseUrl) {
  if (!url) {
    return null;
  }
  try {
    const absoluteUrl = baseUrl ? new URL(url, baseUrl) : new URL(url);
    if (_isValidProtocol(absoluteUrl)) {
      return absoluteUrl;
    }
  } catch (ex) { /* `new URL()` will throw on incorrect data. */ }
  return null;
}

function shadow(obj, prop, value) {
  Object.defineProperty(obj, prop, { value,
                                     enumerable: true,
                                     configurable: true,
                                     writable: false, });
  return value;
}

const BaseException = (function BaseExceptionClosure() {
  function BaseException(message) {
    if (this.constructor === BaseException) {
      unreachable('Cannot initialize BaseException.');
    }
    this.message = message;
    this.name = this.constructor.name;
  }
  BaseException.prototype = new Error();
  BaseException.constructor = BaseException;

  return BaseException;
})();

class PasswordException extends BaseException {
  constructor(msg, code) {
    super(msg);
    this.code = code;
  }
}

class UnknownErrorException extends BaseException {
  constructor(msg, details) {
    super(msg);
    this.details = details;
  }
}

class InvalidPDFException extends BaseException { }

class MissingPDFException extends BaseException { }

class UnexpectedResponseException extends BaseException {
  constructor(msg, status) {
    super(msg);
    this.status = status;
  }
}

/**
 * Error caused during parsing PDF data.
 */
class FormatError extends BaseException { }

/**
 * Error used to indicate task cancellation.
 */
class AbortException extends BaseException { }

const NullCharactersRegExp = /\x00/g;

function removeNullCharacters(str) {
  if (typeof str !== 'string') {
    warn('The argument for removeNullCharacters must be a string.');
    return str;
  }
  return str.replace(NullCharactersRegExp, '');
}

function bytesToString(bytes) {
  assert(bytes !== null && typeof bytes === 'object' &&
         bytes.length !== undefined, 'Invalid argument for bytesToString');
  const length = bytes.length;
  const MAX_ARGUMENT_COUNT = 8192;
  if (length < MAX_ARGUMENT_COUNT) {
    return String.fromCharCode.apply(null, bytes);
  }
  const strBuf = [];
  for (let i = 0; i < length; i += MAX_ARGUMENT_COUNT) {
    const chunkEnd = Math.min(i + MAX_ARGUMENT_COUNT, length);
    const chunk = bytes.subarray(i, chunkEnd);
    strBuf.push(String.fromCharCode.apply(null, chunk));
  }
  return strBuf.join('');
}

function stringToBytes(str) {
  assert(typeof str === 'string', 'Invalid argument for stringToBytes');
  const length = str.length;
  const bytes = new Uint8Array(length);
  for (let i = 0; i < length; ++i) {
    bytes[i] = str.charCodeAt(i) & 0xFF;
  }
  return bytes;
}

/**
 * Gets length of the array (Array, Uint8Array, or string) in bytes.
 * @param {Array|Uint8Array|string} arr
 * @returns {number}
 */
function arrayByteLength(arr) {
  if (arr.length !== undefined) {
    return arr.length;
  }
  assert(arr.byteLength !== undefined);
  return arr.byteLength;
}

/**
 * Combines array items (arrays) into single Uint8Array object.
 * @param {Array} arr - the array of the arrays (Array, Uint8Array, or string).
 * @returns {Uint8Array}
 */
function arraysToBytes(arr) {
  const length = arr.length;
  // Shortcut: if first and only item is Uint8Array, return it.
  if (length === 1 && (arr[0] instanceof Uint8Array)) {
    return arr[0];
  }
  let resultLength = 0;
  for (let i = 0; i < length; i++) {
    resultLength += arrayByteLength(arr[i]);
  }
  let pos = 0;
  const data = new Uint8Array(resultLength);
  for (let i = 0; i < length; i++) {
    let item = arr[i];
    if (!(item instanceof Uint8Array)) {
      if (typeof item === 'string') {
        item = stringToBytes(item);
      } else {
        item = new Uint8Array(item);
      }
    }
    const itemLength = item.byteLength;
    data.set(item, pos);
    pos += itemLength;
  }
  return data;
}

function string32(value) {
  return String.fromCharCode((value >> 24) & 0xff, (value >> 16) & 0xff,
                             (value >> 8) & 0xff, value & 0xff);
}

// Calculate the base 2 logarithm of the number `x`. This differs from the
// native function in the sense that it returns the ceiling value and that it
// returns 0 instead of `Infinity`/`NaN` for `x` values smaller than/equal to 0.
function log2(x) {
  if (x <= 0) {
    return 0;
  }
  return Math.ceil(Math.log2(x));
}

function readInt8(data, start) {
  return (data[start] << 24) >> 24;
}

function readUint16(data, offset) {
  return (data[offset] << 8) | data[offset + 1];
}

function readUint32(data, offset) {
  return ((data[offset] << 24) | (data[offset + 1] << 16) |
         (data[offset + 2] << 8) | data[offset + 3]) >>> 0;
}

// Lazy test the endianness of the platform
// NOTE: This will be 'true' for simulated TypedArrays
function isLittleEndian() {
  const buffer8 = new Uint8Array(4);
  buffer8[0] = 1;
  const view32 = new Uint32Array(buffer8.buffer, 0, 1);
  return (view32[0] === 1);
}

// Checks if it's possible to eval JS expressions.
function isEvalSupported() {
  try {
    new Function(''); // eslint-disable-line no-new, no-new-func
    return true;
  } catch (e) {
    return false;
  }
}

const rgbBuf = ['rgb(', 0, ',', 0, ',', 0, ')'];

class Util {
  // makeCssRgb() can be called thousands of times. Using ´rgbBuf` avoids
  // creating many intermediate strings.
  static makeCssRgb(r, g, b) {
    rgbBuf[1] = r;
    rgbBuf[3] = g;
    rgbBuf[5] = b;
    return rgbBuf.join('');
  }

  // Concatenates two transformation matrices together and returns the result.
  static transform(m1, m2) {
    return [
      m1[0] * m2[0] + m1[2] * m2[1],
      m1[1] * m2[0] + m1[3] * m2[1],
      m1[0] * m2[2] + m1[2] * m2[3],
      m1[1] * m2[2] + m1[3] * m2[3],
      m1[0] * m2[4] + m1[2] * m2[5] + m1[4],
      m1[1] * m2[4] + m1[3] * m2[5] + m1[5]
    ];
  }

  // For 2d affine transforms
  static applyTransform(p, m) {
    const xt = p[0] * m[0] + p[1] * m[2] + m[4];
    const yt = p[0] * m[1] + p[1] * m[3] + m[5];
    return [xt, yt];
  }

  static applyInverseTransform(p, m) {
    const d = m[0] * m[3] - m[1] * m[2];
    const xt = (p[0] * m[3] - p[1] * m[2] + m[2] * m[5] - m[4] * m[3]) / d;
    const yt = (-p[0] * m[1] + p[1] * m[0] + m[4] * m[1] - m[5] * m[0]) / d;
    return [xt, yt];
  }

  // Applies the transform to the rectangle and finds the minimum axially
  // aligned bounding box.
  static getAxialAlignedBoundingBox(r, m) {
    const p1 = Util.applyTransform(r, m);
    const p2 = Util.applyTransform(r.slice(2, 4), m);
    const p3 = Util.applyTransform([r[0], r[3]], m);
    const p4 = Util.applyTransform([r[2], r[1]], m);
    return [
      Math.min(p1[0], p2[0], p3[0], p4[0]),
      Math.min(p1[1], p2[1], p3[1], p4[1]),
      Math.max(p1[0], p2[0], p3[0], p4[0]),
      Math.max(p1[1], p2[1], p3[1], p4[1])
    ];
  }

  static inverseTransform(m) {
    const d = m[0] * m[3] - m[1] * m[2];
    return [m[3] / d, -m[1] / d, -m[2] / d, m[0] / d,
      (m[2] * m[5] - m[4] * m[3]) / d, (m[4] * m[1] - m[5] * m[0]) / d];
  }

  // Apply a generic 3d matrix M on a 3-vector v:
  //   | a b c |   | X |
  //   | d e f | x | Y |
  //   | g h i |   | Z |
  // M is assumed to be serialized as [a,b,c,d,e,f,g,h,i],
  // with v as [X,Y,Z]
  static apply3dTransform(m, v) {
    return [
      m[0] * v[0] + m[1] * v[1] + m[2] * v[2],
      m[3] * v[0] + m[4] * v[1] + m[5] * v[2],
      m[6] * v[0] + m[7] * v[1] + m[8] * v[2]
    ];
  }

  // This calculation uses Singular Value Decomposition.
  // The SVD can be represented with formula A = USV. We are interested in the
  // matrix S here because it represents the scale values.
  static singularValueDecompose2dScale(m) {
    const transpose = [m[0], m[2], m[1], m[3]];

    // Multiply matrix m with its transpose.
    const a = m[0] * transpose[0] + m[1] * transpose[2];
    const b = m[0] * transpose[1] + m[1] * transpose[3];
    const c = m[2] * transpose[0] + m[3] * transpose[2];
    const d = m[2] * transpose[1] + m[3] * transpose[3];

    // Solve the second degree polynomial to get roots.
    const first = (a + d) / 2;
    const second = Math.sqrt((a + d) * (a + d) - 4 * (a * d - c * b)) / 2;
    const sx = first + second || 1;
    const sy = first - second || 1;

    // Scale values are the square roots of the eigenvalues.
    return [Math.sqrt(sx), Math.sqrt(sy)];
  }

  // Normalize rectangle rect=[x1, y1, x2, y2] so that (x1,y1) < (x2,y2)
  // For coordinate systems whose origin lies in the bottom-left, this
  // means normalization to (BL,TR) ordering. For systems with origin in the
  // top-left, this means (TL,BR) ordering.
  static normalizeRect(rect) {
    const r = rect.slice(0); // clone rect
    if (rect[0] > rect[2]) {
      r[0] = rect[2];
      r[2] = rect[0];
    }
    if (rect[1] > rect[3]) {
      r[1] = rect[3];
      r[3] = rect[1];
    }
    return r;
  }

  // Returns a rectangle [x1, y1, x2, y2] corresponding to the
  // intersection of rect1 and rect2. If no intersection, returns 'false'
  // The rectangle coordinates of rect1, rect2 should be [x1, y1, x2, y2]
  static intersect(rect1, rect2) {
    function compare(a, b) {
      return a - b;
    }

    // Order points along the axes
    const orderedX = [rect1[0], rect1[2], rect2[0], rect2[2]].sort(compare);
    const orderedY = [rect1[1], rect1[3], rect2[1], rect2[3]].sort(compare);
    const result = [];

    rect1 = Util.normalizeRect(rect1);
    rect2 = Util.normalizeRect(rect2);

    // X: first and second points belong to different rectangles?
    if ((orderedX[0] === rect1[0] && orderedX[1] === rect2[0]) ||
        (orderedX[0] === rect2[0] && orderedX[1] === rect1[0])) {
      // Intersection must be between second and third points
      result[0] = orderedX[1];
      result[2] = orderedX[2];
    } else {
      return null;
    }

    // Y: first and second points belong to different rectangles?
    if ((orderedY[0] === rect1[1] && orderedY[1] === rect2[1]) ||
        (orderedY[0] === rect2[1] && orderedY[1] === rect1[1])) {
      // Intersection must be between second and third points
      result[1] = orderedY[1];
      result[3] = orderedY[2];
    } else {
      return null;
    }

    return result;
  }
}

const PDFStringTranslateTable = [
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0x2D8, 0x2C7, 0x2C6, 0x2D9, 0x2DD, 0x2DB, 0x2DA, 0x2DC, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x2022, 0x2020, 0x2021, 0x2026, 0x2014,
  0x2013, 0x192, 0x2044, 0x2039, 0x203A, 0x2212, 0x2030, 0x201E, 0x201C,
  0x201D, 0x2018, 0x2019, 0x201A, 0x2122, 0xFB01, 0xFB02, 0x141, 0x152, 0x160,
  0x178, 0x17D, 0x131, 0x142, 0x153, 0x161, 0x17E, 0, 0x20AC
];

function stringToPDFString(str) {
  const length = str.length, strBuf = [];
  if (str[0] === '\xFE' && str[1] === '\xFF') {
    // UTF16BE BOM
    for (let i = 2; i < length; i += 2) {
      strBuf.push(String.fromCharCode(
        (str.charCodeAt(i) << 8) | str.charCodeAt(i + 1)));
    }
  } else {
    for (let i = 0; i < length; ++i) {
      const code = PDFStringTranslateTable[str.charCodeAt(i)];
      strBuf.push(code ? String.fromCharCode(code) : str.charAt(i));
    }
  }
  return strBuf.join('');
}

function stringToUTF8String(str) {
  return decodeURIComponent(escape(str));
}

function utf8StringToString(str) {
  return unescape(encodeURIComponent(str));
}

function isEmptyObj(obj) {
  for (let key in obj) {
    return false;
  }
  return true;
}

function isBool(v) {
  return typeof v === 'boolean';
}

function isNum(v) {
  return typeof v === 'number';
}

function isString(v) {
  return typeof v === 'string';
}

function isArrayBuffer(v) {
  return typeof v === 'object' && v !== null && v.byteLength !== undefined;
}

function isArrayEqual(arr1, arr2) {
  if (arr1.length !== arr2.length) {
    return false;
  }
  return arr1.every(function(element, index) {
    return element === arr2[index];
  });
}

// Checks if ch is one of the following characters: SPACE, TAB, CR or LF.
function isSpace(ch) {
  return (ch === 0x20 || ch === 0x09 || ch === 0x0D || ch === 0x0A);
}

/**
 * Promise Capability object.
 *
 * @typedef {Object} PromiseCapability
 * @property {Promise} promise - A Promise object.
 * @property {boolean} settled - If the Promise has been fulfilled/rejected.
 * @property {function} resolve - Fulfills the Promise.
 * @property {function} reject - Rejects the Promise.
 */

/**
 * Creates a promise capability object.
 * @alias createPromiseCapability
 *
 * @returns {PromiseCapability}
 */
function createPromiseCapability() {
  const capability = Object.create(null);
  let isSettled = false;

  Object.defineProperty(capability, 'settled', {
    get() {
      return isSettled;
    },
  });
  capability.promise = new Promise(function(resolve, reject) {
    capability.resolve = function(data) {
      isSettled = true;
      resolve(data);
    };
    capability.reject = function(reason) {
      isSettled = true;
      reject(reason);
    };
  });
  return capability;
}

const createObjectURL = (function createObjectURLClosure() {
  // Blob/createObjectURL is not available, falling back to data schema.
  const digits =
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

  return function createObjectURL(data, contentType, forceDataSchema = false) {
    if (!forceDataSchema && URL.createObjectURL) {
      const blob = new Blob([data], { type: contentType, });
      return URL.createObjectURL(blob);
    }

    let buffer = `data:${contentType};base64,`;
    for (let i = 0, ii = data.length; i < ii; i += 3) {
      const b1 = data[i] & 0xFF;
      const b2 = data[i + 1] & 0xFF;
      const b3 = data[i + 2] & 0xFF;
      const d1 = b1 >> 2, d2 = ((b1 & 3) << 4) | (b2 >> 4);
      const d3 = i + 1 < ii ? ((b2 & 0xF) << 2) | (b3 >> 6) : 64;
      const d4 = i + 2 < ii ? (b3 & 0x3F) : 64;
      buffer += digits[d1] + digits[d2] + digits[d3] + digits[d4];
    }
    return buffer;
  };
})();

export {
  BaseException,
  FONT_IDENTITY_MATRIX,
  IDENTITY_MATRIX,
  OPS,
  VerbosityLevel,
  UNSUPPORTED_FEATURES,
  AnnotationBorderStyleType,
  AnnotationFieldFlag,
  AnnotationFlag,
  AnnotationMarkedState,
  AnnotationReplyType,
  AnnotationReviewState,
  AnnotationStateModelType,
  AnnotationType,
  FontType,
  ImageKind,
  CMapCompressionType,
  AbortException,
  InvalidPDFException,
  MissingPDFException,
  NativeImageDecoding,
  PasswordException,
  PasswordResponses,
  PermissionFlag,
  StreamType,
  TextRenderingMode,
  UnexpectedResponseException,
  UnknownErrorException,
  Util,
  FormatError,
  arrayByteLength,
  arraysToBytes,
  assert,
  bytesToString,
  createPromiseCapability,
  createObjectURL,
  getVerbosityLevel,
  info,
  isArrayBuffer,
  isArrayEqual,
  isBool,
  isEmptyObj,
  isNum,
  isString,
  isSpace,
  isSameOrigin,
  createValidAbsoluteUrl,
  isLittleEndian,
  isEvalSupported,
  log2,
  readInt8,
  readUint16,
  readUint32,
  removeNullCharacters,
  ReadableStream,
  setVerbosityLevel,
  shadow,
  string32,
  stringToBytes,
  stringToPDFString,
  stringToUTF8String,
  utf8StringToString,
  warn,
  unreachable,
};