@nuralogix.ai/tf-face-tracker-worker-ts
Version:
MediaPipe Tasks-vision Face Landmarker - Module Worker
1,663 lines (1,490 loc) • 409 kB
JavaScript
var __defProp$3 = Object.defineProperty;
var __defNormalProp$3 = (obj, key, value) => key in obj ? __defProp$3(obj, key, { enumerable: true, configurable: true, writable: true, value }) : obj[key] = value;
var __publicField$3 = (obj, key, value) => {
__defNormalProp$3(obj, typeof key !== "symbol" ? key + "" : key, value);
return value;
};
var __accessCheck$1 = (obj, member, msg) => {
if (!member.has(obj))
throw TypeError("Cannot " + msg);
};
var __privateGet = (obj, member, getter) => {
__accessCheck$1(obj, member, "read from private field");
return getter ? getter.call(obj) : member.get(obj);
};
var __privateAdd$1 = (obj, member, value) => {
if (member.has(obj))
throw TypeError("Cannot add the same private member more than once");
member instanceof WeakSet ? member.add(obj) : member.set(obj, value);
};
var __privateSet = (obj, member, value, setter) => {
__accessCheck$1(obj, member, "write to private field");
setter ? setter.call(obj, value) : member.set(obj, value);
return value;
};
var __privateMethod$1 = (obj, member, method) => {
__accessCheck$1(obj, member, "access private method");
return method;
};
var _deviceChangeInProgress, _dispatch$1, dispatch_fn$1;
const roundValue = (value) => {
let result = value.toFixed(2);
if (result === "0")
result = value.toPrecision(1);
return Number(result);
};
const getNewDeviceId = (deviceId, mediaDevices) => {
let newDeviceId = "";
if (mediaDevices.length > 0) {
if (!mediaDevices.find((mediaDevice) => mediaDevice.device.deviceId === deviceId) || deviceId === "") {
newDeviceId = mediaDevices[0].device.deviceId;
}
if (mediaDevices.find((mediaDevice) => mediaDevice.device.deviceId === deviceId)) {
newDeviceId = deviceId;
}
}
return newDeviceId;
};
let removeListener = null;
class CameraController extends EventTarget {
constructor() {
super();
__privateAdd$1(this, _dispatch$1);
__publicField$3(this, "mediaDevices", []);
__publicField$3(this, "selectedDeviceId", "");
__publicField$3(this, "cameraStream", new MediaStream());
__publicField$3(this, "cameraWidth", 0);
__publicField$3(this, "cameraHeight", 0);
__publicField$3(this, "cameraFrameRate", 0);
__publicField$3(this, "settingsInputIds", ["iso", "exposureTime", "focusDistance", "colorTemperature", "zoom"]);
__publicField$3(this, "standardSettingsIds", ["contrast", "saturation", "sharpness", "brightness", "exposureCompensation"]);
__publicField$3(this, "videoTrackCapabilities", {});
__privateAdd$1(this, _deviceChangeInProgress, false);
navigator.mediaDevices.ondevicechange = async () => {
if (!__privateGet(this, _deviceChangeInProgress)) {
__privateSet(this, _deviceChangeInProgress, true);
await this.list();
__privateSet(this, _deviceChangeInProgress, false);
}
};
this.updatePixelRatio = this.updatePixelRatio.bind(this);
this.updatePixelRatio();
}
static init() {
return new this();
}
updatePixelRatio() {
if (removeListener != null) {
removeListener();
}
const mqString = `(resolution: ${window.devicePixelRatio}dppx)`;
const media = matchMedia(mqString);
media.addEventListener("change", this.updatePixelRatio);
removeListener = () => {
media.removeEventListener("change", this.updatePixelRatio);
};
setTimeout(() => {
__privateMethod$1(this, _dispatch$1, dispatch_fn$1).call(this, this.getDeviceAspectRatioChangedEvent());
}, 1e3);
__privateMethod$1(this, _dispatch$1, dispatch_fn$1).call(this, this.getDeviceAspectRatioChangedEvent());
}
/** Enumerates the list of video input devices
*
* The label field for each MediaDevice will be empty if the permission
* is not equal to `granted`
*/
async enumerate() {
const devices = await navigator.mediaDevices.enumerateDevices();
const mediaDevices = devices.filter((device) => device.kind === "videoinput");
const cameras = mediaDevices.map((device) => {
const capabilities = device.getCapabilities();
return { device, capabilities };
});
return cameras;
}
/** Request access to the camera
*
* If the camera permission is set to `prompt` then it will ask for permission.
*
* If permission is granted it returns `true` otherwise it returns `false`
*/
async requestPermission() {
let isPermissionGranted = true;
const enumerateCameras = async () => {
const cameras2 = await this.enumerate();
cameras2.forEach((camera) => {
if (camera.device.label === "")
isPermissionGranted = false;
});
return cameras2;
};
const cameras = await enumerateCameras();
if (isPermissionGranted) {
return {
isPermissionGranted,
cameras
};
} else {
try {
const mediastream = await navigator.mediaDevices.getUserMedia(
{ video: { width: { ideal: 9999 }, height: { ideal: 9999 } } }
);
const tracks = mediastream.getTracks();
tracks.forEach((track) => {
track.stop();
});
isPermissionGranted = true;
const cameras2 = await this.enumerate();
return {
isPermissionGranted,
cameras: cameras2
};
} catch (e) {
return {
isPermissionGranted,
cameras
};
}
}
}
/** Populates the list of `mediaDevices` and sets `selectedDeviceId`
*
* If the camera permission is set to `prompt` then it will prompt for permission.
*
* If camera permission granted it will populate `mediaDevices` with the list of available cameras and
* sets `selectedDeviceId` to that of the first available camera.
*
* If camera permission is blocked, it will set `mediaDevices` to [] and `selectedDeviceId` to an empty string
*
*/
async list() {
const { isPermissionGranted, cameras } = await this.requestPermission();
this.mediaDevices = isPermissionGranted ? cameras : [];
this.selectedDeviceId = getNewDeviceId(this.selectedDeviceId, this.mediaDevices);
__privateMethod$1(this, _dispatch$1, dispatch_fn$1).call(this, this.getSelectedDeviceChangedEvent());
}
/** Change selected media device Id
*
*/
setDeviceId(deviceId) {
if (this.mediaDevices.length) {
if (this.mediaDevices.find((d) => d.device.deviceId === deviceId)) {
this.selectedDeviceId = deviceId;
__privateMethod$1(this, _dispatch$1, dispatch_fn$1).call(this, this.getSelectedDeviceChangedEvent());
}
}
}
/** Start camera
*
*/
async start(frameWidth, frameHeight) {
const supports = navigator.mediaDevices.getSupportedConstraints();
for (const constraint of ["facingMode", "aspectRatio"]) {
if (!(constraint in supports)) {
throw new OverconstrainedError(constraint, "not supported");
}
}
const constraints = {
video: {
// resizeMode: 'none', // means native resolution and frame rate
// facingMode: {exact: 'user'},
deviceId: { exact: this.selectedDeviceId },
aspectRatio: { exact: 16 / 9 },
frameRate: { ideal: 30 },
width: { ideal: frameWidth },
height: { ideal: frameHeight }
}
};
try {
this.cameraStream = await navigator.mediaDevices.getUserMedia(constraints);
const [videoTrack] = this.cameraStream.getVideoTracks();
const videoTrackSettings = videoTrack.getSettings();
const { width, height, frameRate } = videoTrackSettings;
const capabilities = videoTrack.getCapabilities();
this.cameraWidth = width || 0;
this.cameraHeight = height || 0;
this.cameraFrameRate = frameRate || 0;
this.videoTrackCapabilities = Object.fromEntries(
[...this.settingsInputIds, ...this.standardSettingsIds].map(
(id) => {
const mediaSettingsRange = capabilities[id];
return [id, {
isSupported: mediaSettingsRange ? true : false,
min: mediaSettingsRange && mediaSettingsRange.min ? roundValue(mediaSettingsRange.min) : 0,
max: mediaSettingsRange && mediaSettingsRange.max ? roundValue(mediaSettingsRange.max) : 0,
step: mediaSettingsRange && mediaSettingsRange.step ? roundValue(mediaSettingsRange.step) : 0,
value: mediaSettingsRange && videoTrackSettings[id] ? roundValue(videoTrackSettings[id]) : 0
}];
}
)
);
__privateMethod$1(this, _dispatch$1, dispatch_fn$1).call(this, this.getCameraStatusEvent(true));
return true;
} catch (error) {
if (error.name != "OverconstrainedError") {
console.log("Error opening camera", error);
return false;
}
console.log(`This camera cannot produce the requested ${error.constraint}.`);
return false;
}
}
/** Return VideoTrackCapabilities
*
*/
getVideoTrackCapabilities() {
return this.videoTrackCapabilities;
}
/** Stop camera
*
*/
stop() {
if (this.cameraWidth !== 0) {
this.cameraStream.getTracks().forEach((track) => track.stop());
__privateMethod$1(this, _dispatch$1, dispatch_fn$1).call(this, this.getCameraStatusEvent(false));
this.cameraWidth = 0;
this.cameraHeight = 0;
this.cameraFrameRate = 0;
}
}
getCameraStatusEvent(isOpen) {
const event = new CustomEvent("cameraStatus" /* CAMERA_STATUS */, {
detail: {
isOpen,
capabilities: this.videoTrackCapabilities
}
});
return event;
}
getSelectedDeviceChangedEvent() {
const event = new CustomEvent("selectedDeviceChanged" /* SELECTED_DEVICE_CHANGED */, {
detail: {
deviceId: this.selectedDeviceId
}
});
return event;
}
getDeviceAspectRatioChangedEvent() {
const event = new CustomEvent("devicePixelRatioChanged" /* DEVICE_PIXEL_RATIO_CHANGED */, {
detail: {
devicePixelRatio: window.devicePixelRatio
}
});
return event;
}
}
_deviceChangeInProgress = new WeakMap();
_dispatch$1 = new WeakSet();
dispatch_fn$1 = function(event) {
this.dispatchEvent(event);
};
var __defProp$2 = Object.defineProperty;
var __defNormalProp$2 = (obj, key, value) => key in obj ? __defProp$2(obj, key, { enumerable: true, configurable: true, writable: true, value }) : obj[key] = value;
var __publicField$2 = (obj, key, value) => {
__defNormalProp$2(obj, typeof key !== "symbol" ? key + "" : key, value);
return value;
};
const bytesToMegaBytes = (bytes) => bytes / 1024 ** 2;
class VideoController {
constructor(settings) {
__publicField$2(this, "mimeCodec");
__publicField$2(this, "videoElement", document.createElement("video"));
__publicField$2(this, "videoSource", document.createElement("source"));
__publicField$2(this, "canvas", document.createElement("canvas"));
__publicField$2(this, "mediaStream", null);
__publicField$2(this, "bytesDownloaded", 0);
__publicField$2(this, "isVideoLoaded", false);
__publicField$2(this, "ctx");
this.mimeCodec = settings.mimeCodec;
this.getBytesCallback = settings.getBytesCallback;
this.videoLoadedCallback = settings.videoLoadedCallback;
this.videoEndedCallback = settings.videoEndedCallback;
this.videoFrameCallback = this.videoFrameCallback.bind(this);
this.ctx = this.canvas.getContext("2d");
}
static init(settings) {
return new this(settings);
}
getBytesCallback(bytes) {
}
async videoLoadedCallback(isLoaded) {
}
videoEndedCallback() {
}
// getMediaSource() {
// // https://bitmovin.com/managed-media-source
// // New Managed Media Source in Safari 17
// if (window.ManagedMediaSource) {
// console.log('Using ManagedMediaSource');
// return new window.ManagedMediaSource();
// }
// if (window.MediaSource) {
// console.log('Using MediaSource');
// return new window.MediaSource();
// }
// return null;
// }
videoFrameCallback(now, metadata) {
if (this.ctx)
this.ctx.drawImage(this.videoElement, 0, 0, this.canvas.width, this.canvas.height);
this.videoElement.requestVideoFrameCallback(this.videoFrameCallback);
}
captureFromCanvas() {
const { videoWidth, videoHeight } = this.videoElement;
this.canvas.width = videoWidth;
this.canvas.height = videoHeight;
this.videoElement.addEventListener("play", () => {
this.videoElement.requestVideoFrameCallback(this.videoFrameCallback);
});
this.videoElement.addEventListener("playing", () => {
this.mediaStream = this.canvas.captureStream();
});
this.videoElement.addEventListener("ended", () => {
if (this.mediaStream) {
this.mediaStream.getTracks().forEach((track) => track.stop());
this.videoElement.pause();
this.videoEndedCallback();
}
});
}
captureFromVideoElement() {
if ("captureStream" in HTMLVideoElement.prototype) {
this.mediaStream = this.videoElement.captureStream();
}
}
setMediaStream() {
if ("captureStream" in HTMLVideoElement.prototype) {
this.captureFromVideoElement();
this.videoElement.addEventListener("timeupdate", () => {
const { currentTime, duration } = this.videoElement;
if (duration === currentTime && this.mediaStream) {
this.mediaStream.getTracks().forEach((track) => track.stop());
this.videoElement.pause();
this.videoEndedCallback();
}
});
} else {
console.log("captureFromVideoElement not supported");
this.captureFromCanvas();
}
}
async getBuffer(url) {
this.bytesDownloaded = 0;
let videoBuffer = new ArrayBuffer(0);
const response = await fetch(url);
const { body } = response;
if (body) {
const reader = body.getReader();
while (true) {
const { value, done } = await reader.read();
if (done)
break;
this.bytesDownloaded += value.byteLength;
this.getBytesCallback(bytesToMegaBytes(this.bytesDownloaded));
videoBuffer = await new Blob([videoBuffer, value]).arrayBuffer();
}
return videoBuffer;
}
}
async init(url) {
if (typeof url === "undefined" || typeof url !== "string")
return;
this.videoElement = document.createElement("video");
this.videoSource = document.createElement("source");
this.videoSource.type = this.mimeCodec;
this.videoSource.src = url;
this.videoElement.appendChild(this.videoSource);
this.videoElement.playsInline = true;
this.isVideoLoaded = false;
this.videoElement.onloadedmetadata = () => {
this.isVideoLoaded = true;
this.setMediaStream();
this.videoLoadedCallback(this.isVideoLoaded);
};
}
}
var __defProp$1 = Object.defineProperty;
var __defNormalProp$1 = (obj, key, value) => key in obj ? __defProp$1(obj, key, { enumerable: true, configurable: true, writable: true, value }) : obj[key] = value;
var __publicField$1 = (obj, key, value) => {
__defNormalProp$1(obj, typeof key !== "symbol" ? key + "" : key, value);
return value;
};
let interval;
class ImageSequenceController extends EventTarget {
constructor(settings, videoEndedCallback) {
super();
__publicField$1(this, "canvas", document.createElement("canvas"));
__publicField$1(this, "ctx");
__publicField$1(this, "imageBitmaps", []);
__publicField$1(this, "canDrawImage", true);
__publicField$1(this, "settings", {
url: "",
imageName: {
prefix: "",
numberOfDigits: 4,
extension: ""
}
});
this.settings = settings;
this.videoEndedCallback = videoEndedCallback;
this.ctx = this.canvas.getContext("2d");
}
static init(settings, videoEndedCallback) {
return new this(settings, videoEndedCallback);
}
videoEndedCallback() {
}
getImageName(sequence) {
const { url, imageName } = this.settings;
const { prefix, numberOfDigits, extension } = imageName;
return `${url}${prefix}${sequence.toString().padStart(numberOfDigits, "0")}.${extension}`;
}
async getImageBitmapFromUrl(url) {
const response = await fetch(url);
const fileBlob = await response.blob();
const imageBitmap = await createImageBitmap(fileBlob);
return imageBitmap;
}
async getImageBitmapFromArrayOfUrls(urls) {
const imageBitmaps = await Promise.all(urls.map(async (url) => {
const imageBitmap = await this.getImageBitmapFromUrl(url);
return imageBitmap;
}));
this.setImageBitmaps(imageBitmaps);
}
setImageBitmaps(imageBitmaps) {
this.imageBitmaps = imageBitmaps;
}
drawImageBitmapOnCanvas(imageBitmap) {
if (this.ctx) {
const { width, height } = imageBitmap;
if (this.canvas.width !== width)
this.canvas.width = width;
if (this.canvas.height !== height)
this.canvas.height = height;
this.ctx.drawImage(imageBitmap, 0, 0);
imageBitmap.close();
}
}
getMediaStreamReadyEvent(isReady) {
const event = new CustomEvent("imageSequenceMediaStreamReady" /* MEDIASTREAM_READY */, {
detail: {
isReady
}
});
return event;
}
drawImagesOnCanvas() {
const { length } = this.imageBitmaps;
let frameCounter = 0;
interval = setInterval(
() => {
this.drawImageBitmapOnCanvas(this.imageBitmaps[frameCounter]);
if (frameCounter === 0) {
this.dispatchEvent(this.getMediaStreamReadyEvent(true));
}
if (frameCounter === length - 1 || !this.canDrawImage) {
clearInterval(interval);
this.videoEndedCallback();
}
frameCounter += 1;
},
33
);
}
}
var buffer = {};
var base64Js = {};
base64Js.byteLength = byteLength;
base64Js.toByteArray = toByteArray;
base64Js.fromByteArray = fromByteArray;
var lookup = [];
var revLookup = [];
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array;
var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
for (var i$1 = 0, len = code.length; i$1 < len; ++i$1) {
lookup[i$1] = code[i$1];
revLookup[code.charCodeAt(i$1)] = i$1;
}
// Support decoding URL-safe base64 strings, as Node.js does.
// See: https://en.wikipedia.org/wiki/Base64#URL_applications
revLookup['-'.charCodeAt(0)] = 62;
revLookup['_'.charCodeAt(0)] = 63;
function getLens (b64) {
var len = b64.length;
if (len % 4 > 0) {
throw new Error('Invalid string. Length must be a multiple of 4')
}
// Trim off extra bytes after placeholder bytes are found
// See: https://github.com/beatgammit/base64-js/issues/42
var validLen = b64.indexOf('=');
if (validLen === -1) validLen = len;
var placeHoldersLen = validLen === len
? 0
: 4 - (validLen % 4);
return [validLen, placeHoldersLen]
}
// base64 is 4/3 + up to two characters of the original data
function byteLength (b64) {
var lens = getLens(b64);
var validLen = lens[0];
var placeHoldersLen = lens[1];
return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}
function _byteLength (b64, validLen, placeHoldersLen) {
return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}
function toByteArray (b64) {
var tmp;
var lens = getLens(b64);
var validLen = lens[0];
var placeHoldersLen = lens[1];
var arr = new Arr(_byteLength(b64, validLen, placeHoldersLen));
var curByte = 0;
// if there are placeholders, only get up to the last complete 4 chars
var len = placeHoldersLen > 0
? validLen - 4
: validLen;
var i;
for (i = 0; i < len; i += 4) {
tmp =
(revLookup[b64.charCodeAt(i)] << 18) |
(revLookup[b64.charCodeAt(i + 1)] << 12) |
(revLookup[b64.charCodeAt(i + 2)] << 6) |
revLookup[b64.charCodeAt(i + 3)];
arr[curByte++] = (tmp >> 16) & 0xFF;
arr[curByte++] = (tmp >> 8) & 0xFF;
arr[curByte++] = tmp & 0xFF;
}
if (placeHoldersLen === 2) {
tmp =
(revLookup[b64.charCodeAt(i)] << 2) |
(revLookup[b64.charCodeAt(i + 1)] >> 4);
arr[curByte++] = tmp & 0xFF;
}
if (placeHoldersLen === 1) {
tmp =
(revLookup[b64.charCodeAt(i)] << 10) |
(revLookup[b64.charCodeAt(i + 1)] << 4) |
(revLookup[b64.charCodeAt(i + 2)] >> 2);
arr[curByte++] = (tmp >> 8) & 0xFF;
arr[curByte++] = tmp & 0xFF;
}
return arr
}
function tripletToBase64 (num) {
return lookup[num >> 18 & 0x3F] +
lookup[num >> 12 & 0x3F] +
lookup[num >> 6 & 0x3F] +
lookup[num & 0x3F]
}
function encodeChunk (uint8, start, end) {
var tmp;
var output = [];
for (var i = start; i < end; i += 3) {
tmp =
((uint8[i] << 16) & 0xFF0000) +
((uint8[i + 1] << 8) & 0xFF00) +
(uint8[i + 2] & 0xFF);
output.push(tripletToBase64(tmp));
}
return output.join('')
}
function fromByteArray (uint8) {
var tmp;
var len = uint8.length;
var extraBytes = len % 3; // if we have 1 byte left, pad 2 bytes
var parts = [];
var maxChunkLength = 16383; // must be multiple of 3
// go through the array every three bytes, we'll deal with trailing stuff later
for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
parts.push(encodeChunk(uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)));
}
// pad the end with zeros, but make sure to not forget the extra bytes
if (extraBytes === 1) {
tmp = uint8[len - 1];
parts.push(
lookup[tmp >> 2] +
lookup[(tmp << 4) & 0x3F] +
'=='
);
} else if (extraBytes === 2) {
tmp = (uint8[len - 2] << 8) + uint8[len - 1];
parts.push(
lookup[tmp >> 10] +
lookup[(tmp >> 4) & 0x3F] +
lookup[(tmp << 2) & 0x3F] +
'='
);
}
return parts.join('')
}
var ieee754 = {};
/*! ieee754. BSD-3-Clause License. Feross Aboukhadijeh <https://feross.org/opensource> */
ieee754.read = function (buffer, offset, isLE, mLen, nBytes) {
var e, m;
var eLen = (nBytes * 8) - mLen - 1;
var eMax = (1 << eLen) - 1;
var eBias = eMax >> 1;
var nBits = -7;
var i = isLE ? (nBytes - 1) : 0;
var d = isLE ? -1 : 1;
var s = buffer[offset + i];
i += d;
e = s & ((1 << (-nBits)) - 1);
s >>= (-nBits);
nBits += eLen;
for (; nBits > 0; e = (e * 256) + buffer[offset + i], i += d, nBits -= 8) {}
m = e & ((1 << (-nBits)) - 1);
e >>= (-nBits);
nBits += mLen;
for (; nBits > 0; m = (m * 256) + buffer[offset + i], i += d, nBits -= 8) {}
if (e === 0) {
e = 1 - eBias;
} else if (e === eMax) {
return m ? NaN : ((s ? -1 : 1) * Infinity)
} else {
m = m + Math.pow(2, mLen);
e = e - eBias;
}
return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
};
ieee754.write = function (buffer, value, offset, isLE, mLen, nBytes) {
var e, m, c;
var eLen = (nBytes * 8) - mLen - 1;
var eMax = (1 << eLen) - 1;
var eBias = eMax >> 1;
var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0);
var i = isLE ? 0 : (nBytes - 1);
var d = isLE ? 1 : -1;
var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0;
value = Math.abs(value);
if (isNaN(value) || value === Infinity) {
m = isNaN(value) ? 1 : 0;
e = eMax;
} else {
e = Math.floor(Math.log(value) / Math.LN2);
if (value * (c = Math.pow(2, -e)) < 1) {
e--;
c *= 2;
}
if (e + eBias >= 1) {
value += rt / c;
} else {
value += rt * Math.pow(2, 1 - eBias);
}
if (value * c >= 2) {
e++;
c /= 2;
}
if (e + eBias >= eMax) {
m = 0;
e = eMax;
} else if (e + eBias >= 1) {
m = ((value * c) - 1) * Math.pow(2, mLen);
e = e + eBias;
} else {
m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen);
e = 0;
}
}
for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}
e = (e << mLen) | m;
eLen += mLen;
for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}
buffer[offset + i - d] |= s * 128;
};
/*!
* The buffer module from node.js, for the browser.
*
* @author Feross Aboukhadijeh <https://feross.org>
* @license MIT
*/
(function (exports) {
const base64 = base64Js;
const ieee754$1 = ieee754;
const customInspectSymbol =
(typeof Symbol === 'function' && typeof Symbol['for'] === 'function') // eslint-disable-line dot-notation
? Symbol['for']('nodejs.util.inspect.custom') // eslint-disable-line dot-notation
: null;
exports.Buffer = Buffer;
exports.SlowBuffer = SlowBuffer;
exports.INSPECT_MAX_BYTES = 50;
const K_MAX_LENGTH = 0x7fffffff;
exports.kMaxLength = K_MAX_LENGTH;
/**
* If `Buffer.TYPED_ARRAY_SUPPORT`:
* === true Use Uint8Array implementation (fastest)
* === false Print warning and recommend using `buffer` v4.x which has an Object
* implementation (most compatible, even IE6)
*
* Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
* Opera 11.6+, iOS 4.2+.
*
* We report that the browser does not support typed arrays if the are not subclassable
* using __proto__. Firefox 4-29 lacks support for adding new properties to `Uint8Array`
* (See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438). IE 10 lacks support
* for __proto__ and has a buggy typed array implementation.
*/
Buffer.TYPED_ARRAY_SUPPORT = typedArraySupport();
if (!Buffer.TYPED_ARRAY_SUPPORT && typeof console !== 'undefined' &&
typeof console.error === 'function') {
console.error(
'This browser lacks typed array (Uint8Array) support which is required by ' +
'`buffer` v5.x. Use `buffer` v4.x if you require old browser support.'
);
}
function typedArraySupport () {
// Can typed array instances can be augmented?
try {
const arr = new Uint8Array(1);
const proto = { foo: function () { return 42 } };
Object.setPrototypeOf(proto, Uint8Array.prototype);
Object.setPrototypeOf(arr, proto);
return arr.foo() === 42
} catch (e) {
return false
}
}
Object.defineProperty(Buffer.prototype, 'parent', {
enumerable: true,
get: function () {
if (!Buffer.isBuffer(this)) return undefined
return this.buffer
}
});
Object.defineProperty(Buffer.prototype, 'offset', {
enumerable: true,
get: function () {
if (!Buffer.isBuffer(this)) return undefined
return this.byteOffset
}
});
function createBuffer (length) {
if (length > K_MAX_LENGTH) {
throw new RangeError('The value "' + length + '" is invalid for option "size"')
}
// Return an augmented `Uint8Array` instance
const buf = new Uint8Array(length);
Object.setPrototypeOf(buf, Buffer.prototype);
return buf
}
/**
* The Buffer constructor returns instances of `Uint8Array` that have their
* prototype changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of
* `Uint8Array`, so the returned instances will have all the node `Buffer` methods
* and the `Uint8Array` methods. Square bracket notation works as expected -- it
* returns a single octet.
*
* The `Uint8Array` prototype remains unmodified.
*/
function Buffer (arg, encodingOrOffset, length) {
// Common case.
if (typeof arg === 'number') {
if (typeof encodingOrOffset === 'string') {
throw new TypeError(
'The "string" argument must be of type string. Received type number'
)
}
return allocUnsafe(arg)
}
return from(arg, encodingOrOffset, length)
}
Buffer.poolSize = 8192; // not used by this implementation
function from (value, encodingOrOffset, length) {
if (typeof value === 'string') {
return fromString(value, encodingOrOffset)
}
if (ArrayBuffer.isView(value)) {
return fromArrayView(value)
}
if (value == null) {
throw new TypeError(
'The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' +
'or Array-like Object. Received type ' + (typeof value)
)
}
if (isInstance(value, ArrayBuffer) ||
(value && isInstance(value.buffer, ArrayBuffer))) {
return fromArrayBuffer(value, encodingOrOffset, length)
}
if (typeof SharedArrayBuffer !== 'undefined' &&
(isInstance(value, SharedArrayBuffer) ||
(value && isInstance(value.buffer, SharedArrayBuffer)))) {
return fromArrayBuffer(value, encodingOrOffset, length)
}
if (typeof value === 'number') {
throw new TypeError(
'The "value" argument must not be of type number. Received type number'
)
}
const valueOf = value.valueOf && value.valueOf();
if (valueOf != null && valueOf !== value) {
return Buffer.from(valueOf, encodingOrOffset, length)
}
const b = fromObject(value);
if (b) return b
if (typeof Symbol !== 'undefined' && Symbol.toPrimitive != null &&
typeof value[Symbol.toPrimitive] === 'function') {
return Buffer.from(value[Symbol.toPrimitive]('string'), encodingOrOffset, length)
}
throw new TypeError(
'The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' +
'or Array-like Object. Received type ' + (typeof value)
)
}
/**
* Functionally equivalent to Buffer(arg, encoding) but throws a TypeError
* if value is a number.
* Buffer.from(str[, encoding])
* Buffer.from(array)
* Buffer.from(buffer)
* Buffer.from(arrayBuffer[, byteOffset[, length]])
**/
Buffer.from = function (value, encodingOrOffset, length) {
return from(value, encodingOrOffset, length)
};
// Note: Change prototype *after* Buffer.from is defined to workaround Chrome bug:
// https://github.com/feross/buffer/pull/148
Object.setPrototypeOf(Buffer.prototype, Uint8Array.prototype);
Object.setPrototypeOf(Buffer, Uint8Array);
function assertSize (size) {
if (typeof size !== 'number') {
throw new TypeError('"size" argument must be of type number')
} else if (size < 0) {
throw new RangeError('The value "' + size + '" is invalid for option "size"')
}
}
function alloc (size, fill, encoding) {
assertSize(size);
if (size <= 0) {
return createBuffer(size)
}
if (fill !== undefined) {
// Only pay attention to encoding if it's a string. This
// prevents accidentally sending in a number that would
// be interpreted as a start offset.
return typeof encoding === 'string'
? createBuffer(size).fill(fill, encoding)
: createBuffer(size).fill(fill)
}
return createBuffer(size)
}
/**
* Creates a new filled Buffer instance.
* alloc(size[, fill[, encoding]])
**/
Buffer.alloc = function (size, fill, encoding) {
return alloc(size, fill, encoding)
};
function allocUnsafe (size) {
assertSize(size);
return createBuffer(size < 0 ? 0 : checked(size) | 0)
}
/**
* Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
* */
Buffer.allocUnsafe = function (size) {
return allocUnsafe(size)
};
/**
* Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
*/
Buffer.allocUnsafeSlow = function (size) {
return allocUnsafe(size)
};
function fromString (string, encoding) {
if (typeof encoding !== 'string' || encoding === '') {
encoding = 'utf8';
}
if (!Buffer.isEncoding(encoding)) {
throw new TypeError('Unknown encoding: ' + encoding)
}
const length = byteLength(string, encoding) | 0;
let buf = createBuffer(length);
const actual = buf.write(string, encoding);
if (actual !== length) {
// Writing a hex string, for example, that contains invalid characters will
// cause everything after the first invalid character to be ignored. (e.g.
// 'abxxcd' will be treated as 'ab')
buf = buf.slice(0, actual);
}
return buf
}
function fromArrayLike (array) {
const length = array.length < 0 ? 0 : checked(array.length) | 0;
const buf = createBuffer(length);
for (let i = 0; i < length; i += 1) {
buf[i] = array[i] & 255;
}
return buf
}
function fromArrayView (arrayView) {
if (isInstance(arrayView, Uint8Array)) {
const copy = new Uint8Array(arrayView);
return fromArrayBuffer(copy.buffer, copy.byteOffset, copy.byteLength)
}
return fromArrayLike(arrayView)
}
function fromArrayBuffer (array, byteOffset, length) {
if (byteOffset < 0 || array.byteLength < byteOffset) {
throw new RangeError('"offset" is outside of buffer bounds')
}
if (array.byteLength < byteOffset + (length || 0)) {
throw new RangeError('"length" is outside of buffer bounds')
}
let buf;
if (byteOffset === undefined && length === undefined) {
buf = new Uint8Array(array);
} else if (length === undefined) {
buf = new Uint8Array(array, byteOffset);
} else {
buf = new Uint8Array(array, byteOffset, length);
}
// Return an augmented `Uint8Array` instance
Object.setPrototypeOf(buf, Buffer.prototype);
return buf
}
function fromObject (obj) {
if (Buffer.isBuffer(obj)) {
const len = checked(obj.length) | 0;
const buf = createBuffer(len);
if (buf.length === 0) {
return buf
}
obj.copy(buf, 0, 0, len);
return buf
}
if (obj.length !== undefined) {
if (typeof obj.length !== 'number' || numberIsNaN(obj.length)) {
return createBuffer(0)
}
return fromArrayLike(obj)
}
if (obj.type === 'Buffer' && Array.isArray(obj.data)) {
return fromArrayLike(obj.data)
}
}
function checked (length) {
// Note: cannot use `length < K_MAX_LENGTH` here because that fails when
// length is NaN (which is otherwise coerced to zero.)
if (length >= K_MAX_LENGTH) {
throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
'size: 0x' + K_MAX_LENGTH.toString(16) + ' bytes')
}
return length | 0
}
function SlowBuffer (length) {
if (+length != length) { // eslint-disable-line eqeqeq
length = 0;
}
return Buffer.alloc(+length)
}
Buffer.isBuffer = function isBuffer (b) {
return b != null && b._isBuffer === true &&
b !== Buffer.prototype // so Buffer.isBuffer(Buffer.prototype) will be false
};
Buffer.compare = function compare (a, b) {
if (isInstance(a, Uint8Array)) a = Buffer.from(a, a.offset, a.byteLength);
if (isInstance(b, Uint8Array)) b = Buffer.from(b, b.offset, b.byteLength);
if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
throw new TypeError(
'The "buf1", "buf2" arguments must be one of type Buffer or Uint8Array'
)
}
if (a === b) return 0
let x = a.length;
let y = b.length;
for (let i = 0, len = Math.min(x, y); i < len; ++i) {
if (a[i] !== b[i]) {
x = a[i];
y = b[i];
break
}
}
if (x < y) return -1
if (y < x) return 1
return 0
};
Buffer.isEncoding = function isEncoding (encoding) {
switch (String(encoding).toLowerCase()) {
case 'hex':
case 'utf8':
case 'utf-8':
case 'ascii':
case 'latin1':
case 'binary':
case 'base64':
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return true
default:
return false
}
};
Buffer.concat = function concat (list, length) {
if (!Array.isArray(list)) {
throw new TypeError('"list" argument must be an Array of Buffers')
}
if (list.length === 0) {
return Buffer.alloc(0)
}
let i;
if (length === undefined) {
length = 0;
for (i = 0; i < list.length; ++i) {
length += list[i].length;
}
}
const buffer = Buffer.allocUnsafe(length);
let pos = 0;
for (i = 0; i < list.length; ++i) {
let buf = list[i];
if (isInstance(buf, Uint8Array)) {
if (pos + buf.length > buffer.length) {
if (!Buffer.isBuffer(buf)) buf = Buffer.from(buf);
buf.copy(buffer, pos);
} else {
Uint8Array.prototype.set.call(
buffer,
buf,
pos
);
}
} else if (!Buffer.isBuffer(buf)) {
throw new TypeError('"list" argument must be an Array of Buffers')
} else {
buf.copy(buffer, pos);
}
pos += buf.length;
}
return buffer
};
function byteLength (string, encoding) {
if (Buffer.isBuffer(string)) {
return string.length
}
if (ArrayBuffer.isView(string) || isInstance(string, ArrayBuffer)) {
return string.byteLength
}
if (typeof string !== 'string') {
throw new TypeError(
'The "string" argument must be one of type string, Buffer, or ArrayBuffer. ' +
'Received type ' + typeof string
)
}
const len = string.length;
const mustMatch = (arguments.length > 2 && arguments[2] === true);
if (!mustMatch && len === 0) return 0
// Use a for loop to avoid recursion
let loweredCase = false;
for (;;) {
switch (encoding) {
case 'ascii':
case 'latin1':
case 'binary':
return len
case 'utf8':
case 'utf-8':
return utf8ToBytes(string).length
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return len * 2
case 'hex':
return len >>> 1
case 'base64':
return base64ToBytes(string).length
default:
if (loweredCase) {
return mustMatch ? -1 : utf8ToBytes(string).length // assume utf8
}
encoding = ('' + encoding).toLowerCase();
loweredCase = true;
}
}
}
Buffer.byteLength = byteLength;
function slowToString (encoding, start, end) {
let loweredCase = false;
// No need to verify that "this.length <= MAX_UINT32" since it's a read-only
// property of a typed array.
// This behaves neither like String nor Uint8Array in that we set start/end
// to their upper/lower bounds if the value passed is out of range.
// undefined is handled specially as per ECMA-262 6th Edition,
// Section 13.3.3.7 Runtime Semantics: KeyedBindingInitialization.
if (start === undefined || start < 0) {
start = 0;
}
// Return early if start > this.length. Done here to prevent potential uint32
// coercion fail below.
if (start > this.length) {
return ''
}
if (end === undefined || end > this.length) {
end = this.length;
}
if (end <= 0) {
return ''
}
// Force coercion to uint32. This will also coerce falsey/NaN values to 0.
end >>>= 0;
start >>>= 0;
if (end <= start) {
return ''
}
if (!encoding) encoding = 'utf8';
while (true) {
switch (encoding) {
case 'hex':
return hexSlice(this, start, end)
case 'utf8':
case 'utf-8':
return utf8Slice(this, start, end)
case 'ascii':
return asciiSlice(this, start, end)
case 'latin1':
case 'binary':
return latin1Slice(this, start, end)
case 'base64':
return base64Slice(this, start, end)
case 'ucs2':
case 'ucs-2':
case 'utf16le':
case 'utf-16le':
return utf16leSlice(this, start, end)
default:
if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
encoding = (encoding + '').toLowerCase();
loweredCase = true;
}
}
}
// This property is used by `Buffer.isBuffer` (and the `is-buffer` npm package)
// to detect a Buffer instance. It's not possible to use `instanceof Buffer`
// reliably in a browserify context because there could be multiple different
// copies of the 'buffer' package in use. This method works even for Buffer
// instances that were created from another copy of the `buffer` package.
// See: https://github.com/feross/buffer/issues/154
Buffer.prototype._isBuffer = true;
function swap (b, n, m) {
const i = b[n];
b[n] = b[m];
b[m] = i;
}
Buffer.prototype.swap16 = function swap16 () {
const len = this.length;
if (len % 2 !== 0) {
throw new RangeError('Buffer size must be a multiple of 16-bits')
}
for (let i = 0; i < len; i += 2) {
swap(this, i, i + 1);
}
return this
};
Buffer.prototype.swap32 = function swap32 () {
const len = this.length;
if (len % 4 !== 0) {
throw new RangeError('Buffer size must be a multiple of 32-bits')
}
for (let i = 0; i < len; i += 4) {
swap(this, i, i + 3);
swap(this, i + 1, i + 2);
}
return this
};
Buffer.prototype.swap64 = function swap64 () {
const len = this.length;
if (len % 8 !== 0) {
throw new RangeError('Buffer size must be a multiple of 64-bits')
}
for (let i = 0; i < len; i += 8) {
swap(this, i, i + 7);
swap(this, i + 1, i + 6);
swap(this, i + 2, i + 5);
swap(this, i + 3, i + 4);
}
return this
};
Buffer.prototype.toString = function toString () {
const length = this.length;
if (length === 0) return ''
if (arguments.length === 0) return utf8Slice(this, 0, length)
return slowToString.apply(this, arguments)
};
Buffer.prototype.toLocaleString = Buffer.prototype.toString;
Buffer.prototype.equals = function equals (b) {
if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer')
if (this === b) return true
return Buffer.compare(this, b) === 0
};
Buffer.prototype.inspect = function inspect () {
let str = '';
const max = exports.INSPECT_MAX_BYTES;
str = this.toString('hex', 0, max).replace(/(.{2})/g, '$1 ').trim();
if (this.length > max) str += ' ... ';
return '<Buffer ' + str + '>'
};
if (customInspectSymbol) {
Buffer.prototype[customInspectSymbol] = Buffer.prototype.inspect;
}
Buffer.prototype.compare = function compare (target, start, end, thisStart, thisEnd) {
if (isInstance(target, Uint8Array)) {
target = Buffer.from(target, target.offset, target.byteLength);
}
if (!Buffer.isBuffer(target)) {
throw new TypeError(
'The "target" argument must be one of type Buffer or Uint8Array. ' +
'Received type ' + (typeof target)
)
}
if (start === undefined) {
start = 0;
}
if (end === undefined) {
end = target ? target.length : 0;
}
if (thisStart === undefined) {
thisStart = 0;
}
if (thisEnd === undefined) {
thisEnd = this.length;
}
if (start < 0 || end > target.length || thisStart < 0 || thisEnd > this.length) {
throw new RangeError('out of range index')
}
if (thisStart >= thisEnd && start >= end) {
return 0
}
if (thisStart >= thisEnd) {
return -1
}
if (start >= end) {
return 1
}
start >>>= 0;
end >>>= 0;
thisStart >>>= 0;
thisEnd >>>= 0;
if (this === target) return 0
let x = thisEnd - thisStart;
let y = end - start;
const len = Math.min(x, y);
const thisCopy = this.slice(thisStart, thisEnd);
const targetCopy = target.slice(start, end);
for (let i = 0; i < len; ++i) {
if (thisCopy[i] !== targetCopy[i]) {
x = thisCopy[i];
y = targetCopy[i];
break
}
}
if (x < y) return -1
if (y < x) return 1
return 0
};
// Finds either the first index of `val` in `buffer` at offset >= `byteOffset`,
// OR the last index of `val` in `buffer` at offset <= `byteOffset`.
//
// Arguments:
// - buffer - a Buffer to search
// - val - a string, Buffer, or number
// - byteOffset - an index into `buffer`; will be clamped to an int32
// - encoding - an optional encoding, relevant is val is a string
// - dir - true for indexOf, false for lastIndexOf
function bidirectionalIndexOf (buffer, val, byteOffset, encoding, dir) {
// Empty buffer means no match
if (buffer.length === 0) return -1
// Normalize byteOffset
if (typeof byteOffset === 'string') {
encoding = byteOffset;
byteOffset = 0;
} else if (byteOffset > 0x7fffffff) {
byteOffset = 0x7fffffff;
} else if (byteOffset < -0x80000000) {
byteOffset = -0x80000000;
}
byteOffset = +byteOffset; // Coerce to Number.
if (numberIsNaN(byteOffset)) {
// byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
byteOffset = dir ? 0 : (buffer.length - 1);
}
// Normalize byteOffset: negative offsets start from the end of the buffer
if (byteOffset < 0) byteOffset = buffer.length + byteOffset;
if (byteOffset >= buffer.length) {
if (dir) return -1
else byteOffset = buffer.length - 1;
} else if (byteOffset < 0) {
if (dir) byteOffset = 0;
else return -1
}
// Normalize val
if (typeof val === 'string') {
val = Buffer.from(val, encoding);
}
// Finally, search either indexOf (if dir is true) or lastIndexOf
if (Buffer.isBuffer(val)) {
// Special case: looking for empty string/buffer always fails
if (val.length === 0) {
return -1
}
return arrayIndexOf(buffer, val, byteOffset, encoding, dir)
} else if (typeof val === 'number') {
val = val & 0xFF; // Search for a byte value [0-255]
if (typeof Uint8Array.prototype.indexOf === 'function') {
if (dir) {
return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset)
} else {
return Uint8Array.prototype.lastIndexOf.call(buffer, val, byteOffset)
}
}
return arrayIndexOf(buffer, [val], byteOffset, encoding, dir)
}
throw new TypeError('val must be string, number or Buffer')
}
function arrayIndexOf (arr, val, byteOffset, encoding, dir) {
let indexSize = 1;
let arrLength = arr.length;
let valLength = val.length;
if (encoding !== undefined) {
encoding = String(encoding).toLowerCase();
if (encoding === 'ucs2' || encoding === 'ucs-2' ||
encoding === 'utf16le' || encoding === 'utf-16le') {
if (arr.length < 2 || val.length < 2) {
return -1
}
indexSize = 2;
arrLength /= 2;
valLength /= 2;
byteOffset /= 2;
}
}
function read (buf, i) {
if (indexSize === 1) {
return buf[i]
} else {
return buf.readUInt16BE(i * indexSize)
}
}
let i;
if (dir) {
let foundIndex = -1;
for (i = byteOffset; i < arrLength; i++) {
if (read(arr, i) === read(val, foundIndex === -1 ? 0 : i - foundIndex)) {
if (foundIndex === -1) foundIndex = i;
if (i - foundIndex + 1 === valLength) return foundIndex * indexSize
} else {
if (foundIndex !== -1) i -= i - foundIndex;
foundIndex = -1;
}
}
} else {
if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength;
for (i = byteOffset; i >= 0; i--) {
let found = true;
for (let j = 0; j < valLength; j++) {
if (read(arr, i + j) !== read(val, j)) {
found = false;
break
}
}
if (found) return i
}
}
return -1
}
Buffer.prototype.includes = function includes (val, byteOffset, encoding) {
return this.indexOf(val, byteOffset, encoding) !== -1
};
Buffer.prototype.indexOf = function indexOf (val, byteOffset, encoding) {
return bidirectionalIndexOf(this, val, byteOffset, encoding, true)
};
Buffer.prototype.lastIndexOf = function lastIndexOf (val, byteOffset, encoding) {
return bidirectionalIndexOf(this, val, byteOffset, encoding, false)
};
function hexWrite (buf, string, offset, length) {
offset = Number(offset) || 0;
const remaining = buf.length - offset;
if (!length) {
length = remaining;
} else {
length = Number(length);
if (length > remaining) {
length = remaining;
}
}
const strLen = string.length;
if (length > strLen / 2) {
length = strLen / 2;
}
let i;
for (i = 0; i < length; ++i) {
const parsed = parseInt(string.substr(i * 2, 2), 16);
if (numberIsNaN(parsed)) return i
buf[offset + i] = parsed;
}
return i
}
function utf8Write (buf, string, offset, length) {
return blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length)
}
function asciiWrite (buf, string, offset, length) {
return blitBuffer(asciiToBytes(string), buf, offset, length)
}
function base64Write (buf, string, offset, length) {
return blitBuffer(base64ToBytes(string), buf, offset, length)
}
function ucs2Write (buf, string, offset, length) {
return blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length)
}
Buffer.prototype.write = function write (string, offset, length, encoding) {
// Buffer#write(string)
if (offset === undefined) {
encoding = 'utf8';
length = this.length;
offset = 0;
// Buffer#write(string, encoding)
} else if (length === undefined && typeof offset === 'string') {
encoding = offset;
length = this.length;
offset = 0;
// Buffer#write(string, offset[, length][, encoding])
} else if (isFinite(offset)) {
offset = offset >>> 0;
if (isFinite(length)) {
length = length >>> 0;
if (encoding === undefined) encoding = 'utf8';
} else {
encoding = length;
length = undefined;
}
} else {
throw new Error(
'Buffer.write(string, encoding, offset[, length]) is no longer supported'
)
}
const remaining = this.length - offset;
if (length === undefined || length > remaining) length = remaining;
if ((string.length > 0 && (length < 0 || offset < 0)) || offset > this.length) {
throw new RangeError('Attempt to write outside buffer bounds')
}
if (!encoding) encoding = 'utf8';
let loweredCase = false;
for (;;) {
switch (encoding) {
case 'hex':
return hexWrite(this, string, offset, length)
case 'utf8':
case 'utf-8':
return utf8Write(this, string, offset, length)
case 'ascii':
case 'latin1':
case 'binary':
return asciiWrite(this, string, offset, length)
case 'base64':
// Warning: maxLength not taken into account in base64Write
return base64Write(this, string, offset, length)
case 'ucs2':