DataView

DataView는 플랫폼의 바이트 정렬 방법과 관계없이 ArrayBuffer에서 다양한 형태의 데이터를 읽고 쓰기 위한 저수준 인터페이스를 제공합니다.

문법

new DataView(buffer [, byteOffset [, byteLength]])

파라미터

buffer

새로운 데이터뷰 객체의 저장소로서 사용될 ArrayBuffer

byteOffset Optional

새로운 뷰가 참조할, 버퍼의 첫번째 위치부터 이동할 바이트 크기. (즉, 데이터뷰에서 버퍼를 읽기 위해 시작하는 위치)
지정하지 않았을 경우, 해당 버퍼의 뷰는 첫번째 바이트에서 시작.

byteLength Optional

(버퍼에서 읽을) 바이트 길이. 지정하지 않으면 뷰와 버퍼의 길이는 동일.

반환값

데이터 버퍼를 연결하는 새로운 데이터뷰.

Errors thrown

RangeError

Thrown if the byteOffset and byteLength result in the specified view extending past the end of the buffer.

Description

Endianness

Multi-byte number formats are represented in memory differently depending on machine architecture, see Endianness for an explanation. DataView accessors provide explicit control of how data will be accessed irrespective of the platform architecture's endianness.

var littleEndian = (function() {
  var buffer = new ArrayBuffer(2);
  new DataView(buffer).setInt16(0, 256, true /* littleEndian */);
  // Int16Array uses the platform's endianness.
  return new Int16Array(buffer)[0] === 256;
})();
console.log(littleEndian); // true or false

Properties

All DataView instances inherit from DataView.prototype and allows the addition of properties to all DataView objects.

DataView.prototype.constructor

Specifies the function that creates an object's prototype. The initial value is the standard built-in DataView constructor.

DataView.prototype.buffer Read only

The ArrayBuffer referenced by this view. Fixed at construction time and thus read only.

DataView.prototype.byteLength Read only

The length (in bytes) of this view from the start of its ArrayBuffer. Fixed at construction time and thus read only.

DataView.prototype.byteOffset Read only

The offset (in bytes) of this view from the start of its ArrayBuffer. Fixed at construction time and thus read only.

Methods

Read

DataView.prototype.getInt8()

Gets a signed 8-bit integer (byte) at the specified byte offset from the start of the view.

DataView.prototype.getUint8()

Gets an unsigned 8-bit integer (unsigned byte) at the specified byte offset from the start of the view.

DataView.prototype.getInt16()

Gets a signed 16-bit integer (short) at the specified byte offset from the start of the view.

DataView.prototype.getUint16()

Gets an unsigned 16-bit integer (unsigned short) at the specified byte offset from the start of the view.

DataView.prototype.getInt32()

Gets a signed 32-bit integer (long) at the specified byte offset from the start of the view.

DataView.prototype.getUint32()

Gets an unsigned 32-bit integer (unsigned long) at the specified byte offset from the start of the view.

DataView.prototype.getFloat32()

Gets a signed 32-bit float (float) at the specified byte offset from the start of the view.

DataView.prototype.getFloat64()

Gets a signed 64-bit float (double) at the specified byte offset from the start of the view.

Write

DataView.prototype.setInt8()

Stores a signed 8-bit integer (byte) value at the specified byte offset from the start of the view.

DataView.prototype.setUint8()

Stores an unsigned 8-bit integer (unsigned byte) value at the specified byte offset from the start of the view.

DataView.prototype.setInt16()

Stores a signed 16-bit integer (short) value at the specified byte offset from the start of the view.

DataView.prototype.setUint16()

Stores an unsigned 16-bit integer (unsigned short) value at the specified byte offset from the start of the view.

DataView.prototype.setInt32()

Stores a signed 32-bit integer (long) value at the specified byte offset from the start of the view.

DataView.prototype.setUint32()

Stores an unsigned 32-bit integer (unsigned long) value at the specified byte offset from the start of the view.

DataView.prototype.setFloat32()

Stores a signed 32-bit float (float) value at the specified byte offset from the start of the view.

DataView.prototype.setFloat64()

Stores a signed 64-bit float (double) value at the specified byte offset from the start of the view.

Example

var buffer = new ArrayBuffer(16);
var dv = new DataView(buffer, 0);

dv.setInt16(1, 42);
dv.getInt16(1); //42

Specifications

Browser compatibility

Compatibility notes

Starting with Firefox 40, DataView requires to be constructed with a new operator. Calling DataView() as a function without new, will throw a TypeError from now on .

var dv = DataView(buffer, 0); 
// TypeError: calling a builtin DataView constructor without new is forbidden

var dv = new DataView(buffer, 0);

See also

• jDataView: JavaScript library that polyfills and extends the DataView API to all browsers and Node.js.
• ArrayBuffer
• SharedArrayBuffer