1  export default class BufferList {
 2    constructor(public buffers: Buffer[] = []) {}
 3  
 4    public add(buffer: Buffer, front?: boolean) {
 5      this.buffers[front ? 'unshift' : 'push'](buffer)
 6      return this
 7    }
 8  
 9    public addInt16(val: number, front?: boolean) {
10      return this.add(Buffer.from([val >>> 8, val >>> 0]), front)
11    }
12  
13    public getByteLength() {
14      return this.buffers.reduce(function (previous, current) {
15        return previous + current.length
16      }, 0)
17    }
18  
19    public addInt32(val: number, first?: boolean) {
20      return this.add(
21        Buffer.from([(val >>> 24) & 0xff, (val >>> 16) & 0xff, (val >>> 8) & 0xff, (val >>> 0) & 0xff]),
22        first
23      )
24    }
25  
26    public addCString(val: string, front?: boolean) {
27      const len = Buffer.byteLength(val)
28      const buffer = Buffer.alloc(len + 1)
29      buffer.write(val)
30      buffer[len] = 0
31      return this.add(buffer, front)
32    }
33  
34    public addString(val: string, front?: boolean) {
35      const len = Buffer.byteLength(val)
36      const buffer = Buffer.alloc(len)
37      buffer.write(val)
38      return this.add(buffer, front)
39    }
40  
41    public addChar(char: string, first?: boolean) {
42      return this.add(Buffer.from(char, 'utf8'), first)
43    }
44  
45    public addByte(byte: number) {
46      return this.add(Buffer.from([byte]))
47    }
48  
49    public join(appendLength?: boolean, char?: string): Buffer {
50      let length = this.getByteLength()
51      if (appendLength) {
52        this.addInt32(length + 4, true)
53        return this.join(false, char)
54      }
55      if (char) {
56        this.addChar(char, true)
57        length++
58      }
59      const result = Buffer.alloc(length)
60      let index = 0
61      this.buffers.forEach(function (buffer) {
62        buffer.copy(result, index, 0)
63        index += buffer.length
64      })
65      return result
66    }
67  }