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• 描述
• 构造函数
• 实例特性
• 实例方法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

DataView view provides a low-level interface for reading and writing multiple number types in a binary ArrayBuffer , without having to care about the platform's endianness .

描述

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 is accessed, regardless of the executing computer'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
					

64-bit Integer Values

Because JavaScript does not currently include standard support for 64-bit integer values, DataView does not offer native 64-bit operations. As a workaround, you could implement your own getUint64() function to obtain a value with precision up to Number.MAX_SAFE_INTEGER , which could suffice for certain cases.

function getUint64(dataview, byteOffset, littleEndian) {
  // split 64-bit number into two 32-bit (4-byte) parts
  const left =  dataview.getUint32(byteOffset, littleEndian);
  const right = dataview.getUint32(byteOffset+4, littleEndian);
  // combine the two 32-bit values
  const combined = littleEndian? left + 2**32*right : 2**32*left + right;
  if (!Number.isSafeInteger(combined))
    console.warn(combined, 'exceeds MAX_SAFE_INTEGER. Precision may be lost');
  return combined;
}
					

Alternatively, if you need full 64-bit range, you can create a BigInt . Further, although native BigInts are much faster than user-land library equivalents, BigInts will always be much slower than 32-bit integers in JavaScript due to the nature of their variable size.

const BigInt = window.BigInt, bigThirtyTwo = BigInt(32), bigZero = BigInt(0);
function getUint64BigInt(dataview, byteOffset, littleEndian) {
  // split 64-bit number into two 32-bit (4-byte) parts
  const left = BigInt(dataview.getUint32(byteOffset|0, !!littleEndian)>>>0);
  const right = BigInt(dataview.getUint32((byteOffset|0) + 4|0, !!littleEndian)>>>0);
  // combine the two 32-bit values and return
  return littleEndian ? (right<<bigThirtyTwo)|left : (left<<bigThirtyTwo)|right;
}
					

构造函数

DataView()

创建新的 DataView 对象。

实例特性

DataView.prototype.buffer

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

DataView.prototype.byteLength

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

DataView.prototype.byteOffset

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

实例方法

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.

DataView.prototype.getBigInt64()

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

DataView.prototype.getBigUint64()

Gets an unsigned 64-bit integer (unsigned long long) at the specified byte offset from the start of the view.

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.

DataView.prototype.setBigInt64()

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

DataView.prototype.setBigUint64()

Stores an unsigned 64-bit integer (unsigned long long) value at the specified byte offset from the start of the view.

范例

Using DataView

var buffer = new ArrayBuffer(16);
var view = new DataView(buffer, 0);
view.setInt16(1, 42);
view.getInt16(1); // 42
					

规范

规范
ECMAScript (ECMA-262) The definition of 'DataView' in that specification.

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
DataView	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
DataView() 构造函数	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
buffer	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
byteLength	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
byteOffset	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getBigInt64	Chrome 67	Edge 79	Firefox 68	IE No	Opera 54	Safari No	WebView Android 67	Chrome Android 67	Firefox Android 68	Opera Android 48	Safari iOS No	Samsung Internet Android 9.0	nodejs 10.4.0
getBigUint64	Chrome 67	Edge 79	Firefox 68	IE No	Opera 54	Safari No	WebView Android 67	Chrome Android 67	Firefox Android 68	Opera Android 48	Safari iOS No	Samsung Internet Android 9.0	nodejs 10.4.0
getFloat32	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getFloat64	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getInt16	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getInt32	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getInt8	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getUint16	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getUint32	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
getUint8	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setBigInt64	Chrome 67	Edge 79	Firefox 68	IE No	Opera 54	Safari No	WebView Android 67	Chrome Android 67	Firefox Android 68	Opera Android 48	Safari iOS No	Samsung Internet Android 9.0	nodejs 10.4.0
setBigUint64	Chrome 67	Edge 79	Firefox 68	IE No	Opera 54	Safari No	WebView Android 67	Chrome Android 67	Firefox Android 68	Opera Android 48	Safari iOS No	Samsung Internet Android 9.0	nodejs 10.4.0
setFloat32	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setFloat64	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setInt16	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setInt32	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setInt8	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setUint16	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setUint32	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
setUint8	Chrome 9	Edge 12	Firefox 15	IE 10	Opera 12.1	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 15	Opera Android 12.1	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10

图例

完整支持

完整支持

不支持

不支持

另请参阅

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

元数据

• 最后修改： May 19, 2020

相关话题

1. 标准内置对象
2. DataView
3. 特性
   1. DataView.prototype.buffer
   2. DataView.prototype.byteLength
   3. DataView.prototype.byteOffset
4. 方法
   1. DataView.prototype.getBigInt64()
   2. DataView.prototype.getBigUint64()
   3. DataView.prototype.getFloat32()
   4. DataView.prototype.getFloat64()
   5. DataView.prototype.getInt16()
   6. DataView.prototype.getInt32()
   7. DataView.prototype.getInt8()
   8. DataView.prototype.getUint16()
   9. DataView.prototype.getUint32()
   10. DataView.prototype.getUint8()
   11. DataView.prototype.setBigInt64()
   12. DataView.prototype.setBigUint64()
   13. DataView.prototype.setFloat32()
   14. DataView.prototype.setFloat64()
   15. DataView.prototype.setInt16()
   16. DataView.prototype.setInt32()
   17. DataView.prototype.setInt8()
   18. DataView.prototype.setUint16()
   19. DataView.prototype.setUint32()
   20. DataView.prototype.setUint8()
5. 继承：
6. 函数
7. 特性
   1. Function.arguments
   2. Function.caller
   3. Function.displayName
   4. Function.length
   5. Function.name
8. 方法
   1. Function.prototype.apply()
   2. Function.prototype.bind()
   3. Function.prototype.call()
   4. Function.prototype.toSource()
   5. Function.prototype.toString()
9. 对象
10. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
11. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()