Node.js Buffer.writeUInt8()方法
原文:https://www . geesforgeks . org/node-js-buffer-writeuint 8-method/
Buffer.writeUInt8()方法是 Buffer 模块中类 Buffer 的内置应用编程接口，用于将值写入指定偏移量处的缓冲区。该值应为有效的无符号 8 位整数，否则行为未定义。
语法:
Buffer.writeUInt8( value, offset )
参数:该方法接受两个参数，如上所述，如下所述:
- Value: The unsigned integer value to be written into the buffer.
- Offset: indicates the number of bytes to skip before writing to the buffer. The offset can be in the range of 0 < = offset < = buf.length–1 . The default value of offset for is 0.
返回值:返回在指定偏移量插入值的缓冲区。
下面的例子说明了 Buffer.writeUInt8() 方法在 Node.js 中的使用:
例 1:
// Node.js program to demonstrate the
// Buffer.writeUInt8() method
// Creating a buffer
const buf = Buffer.allocUnsafe(5);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x14, 0);
// Display the buffer
console.log(buf);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x15, 1);
// Display the buffer
console.log(buf);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x16, 4);
// Display the buffer
console.log(buf);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x17, 3);
// Display the buffer
console.log(buf);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x18, 2);
// Display the result
console.log(buf);
输出:
<Buffer 14 00 00 00 d6>
<Buffer 14 15 00 00 d6>
<Buffer 14 15 00 00 16>
<Buffer 14 15 00 17 16>
<Buffer 14 15 18 17 16>
例 2:
// Node.js program to demonstrate the
// Buffer.writeUInt8() method
// Creating a buffer
const buf = Buffer.allocUnsafe(3);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x11, 0);
// Display the buffer
console.log(buf);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x22, 1);
// Display the buffer
console.log(buf);
// Using Buffer.writeUInt8() method
buf.writeUInt8(0x33, 2);
// Display the buffer
console.log(buf);
输出:
<Buffer 11 e7 31>
<Buffer 11 22 31>
<Buffer 11 22 33>
注意:以上程序使用node index.js命令编译运行。
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