BufferStream.js

"use strict";

class BufferStream {
  constructor(buf, isBigEndian = true) {
    this.pos = 0;
    this.buf = Buffer.from(buf);
    this.isBigEndian = isBigEndian;
  }

  read(length) {
    let part = Buffer.from(this.buf.slice(this.pos, this.pos + length));
    this.pos += length;
    return part;
  }

  readInt8() {
    let val = this.buf.readInt8(this.pos);
    this.pos += 1;
    return val;
  }

  readInt16() {
    let val;
    if(this.isBigEndian) val = this.buf.readInt16BE(this.pos);
    else val = this.buf.readInt16LE(this.pos);
    this.pos += 2;
    return val;
  }

  readInt32() {
    let val;
    if(this.isBigEndian) val = this.buf.readInt32BE(this.pos);
    else val = this.buf.readInt32LE(this.pos);
    this.pos += 4;
    return val;
  }

  readUInt8() {
    let val = this.buf.readUInt8(this.pos);
    this.pos += 1;
    return val;
  }

  readUInt16() {
    let val;
    if(this.isBigEndian) val = this.buf.readUInt16BE(this.pos);
    else val = this.buf.readUInt16LE(this.pos);
    this.pos += 2;
    return val;
  }

  readUInt32() {
    let val;
    if(this.isBigEndian) val = this.buf.readUInt32BE(this.pos);
    else val = this.buf.readUInt32LE(this.pos);
    this.pos += 4;
    return val;
  }

  readFloat() {
    let val;
    if(this.isBigEndian) val = this.buf.readFloatBE(this.pos);
    else val = this.buf.readFloatLE(this.pos);
    this.pos += 4;
    return val;
  }

  readDouble() {
    let val;
    if(this.isBigEndian) val = this.buf.readDoubleBE(this.pos);
    else val = this.buf.readDoubleLE(this.pos);
    this.pos += 8;
    return val;
  }

  readString() {
    let nextNull = this.buf.indexOf(0, this.pos);
    if(nextNull === -1) return null;

    let part = this.buf.slice(this.pos, nextNull)
    this.pos = nextNull + 1;
    return part;
  }

  align(size) {
    if(this.pos % size !== 0) {
      this.pos += size - (this.pos % size);
    }
  }
}

module.exports = BufferStream;