Node.js Buffer.readInt16LE()方法
原文:https://www . geesforgeks . org/node-js-buffer-readint 16le-method/
Buffer.readUInt16LE()方法是 Buffer 模块中类 Buffer 的内置应用编程接口，用于以小端格式从指定偏移量的已分配缓冲区中读取 16 位值。
语法:
Buffer.readUInt16LE(offset)
参数:该方法接受单参数偏移量，该偏移量指定读取前要跳过的字节数，或者简单地表示缓冲区中的索引。偏移量的值为 0 < =偏移量< =缓冲区长度–2。其默认值为 0。
返回值:这个方法返回一个从缓冲区读取的小端格式的整数值。
下面的例子说明了在 Node.js 中使用 Buffer.readUInt16LE()方法:
例 1:
// Node program to demonstrate the
// Buffer.readInt16LE() Method
// Allocating buffer from array
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98]);
// Printing allocated buffer
console.log(buf);
// Reading 16bits data from the buffer
// and printing it as a string
console.log(buf.readUInt16LE(0).toString(16));
console.log(buf.readUInt16LE(1).toString(16));
console.log(buf.readUInt16LE(2).toString(16));
输出:
<Buffer 21 09 19 98>
921
1909
9819
例 2:
// Node program to demonstrate the
// Buffer.readInt16LE() Method
// Allocating buffer from array
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98]);
// Printing allocated buffer
console.log(buf);
// Reading 16bits data from the buffer
// and printing it as a string
console.log(buf.readUInt16LE(0).toString(16));
console.log(buf.readUInt16BE(0).toString(16));
console.log(buf.readUInt16LE(1).toString(16));
console.log(buf.readUInt16BE(1).toString(16));
console.log(buf.readUInt16LE(2).toString(16));
console.log(buf.readUInt16BE(2).toString(16));
输出:
<Buffer 21 09 19 98>
921
2109
1909
919
9819
1998
例 3:
// Node program to demonstrate the
// Buffer.readInt16LE() Method
// Allocating buffer from array
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98]);
// Printing allocated buffer
console.log(buf);
// Reading 16bits data from the buffer
// and printing it as a string
console.log(buf.readUInt16LE(0).toString(16));
console.log(buf.readUInt16LE(1).toString(16));
console.log(buf.readUInt16LE(2).toString(16));
// Wrong index is provoded to produce error
console.log(buf.readUInt16LE(3).toString(16));
输出:
<Buffer 21 09 19 98>
921
1909
9819
internal/buffer.js:49
throw new ERR_OUT_OF_RANGE(type || 'offset',
^
RangeError [ERR_OUT_OF_RANGE]: The value of "offset" is out of range.
It must be >= 0 and <= 2\. Received 3
at boundsError (internal/buffer.js:49:9)
at Buffer.readUInt16LE (internal/buffer.js:128:5)
. . .
注意:以上程序使用node index.js命令编译运行。
参考:T2】https://nodejs . org/API/buffer . html # buffer _ buf _ readuint 16 le _ offset
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