BinaryWriter to be used with Rive projects

BinaryWriter.ts

enum Endian {
  Little = "little",
  Big = "big",
}
class BinaryWriter {
  variableEncodeList = new Uint8Array(8);
  writeIndex = 0;
  alignment: number; // Add this line
  endian: Endian; // Add this line
  buffer: Uint8Array; // Add this line

  constructor(alignment = 1024, endian = Endian.Little) {
    this.alignment = Math.max(1, alignment);
    this.endian = endian;
    this.buffer = new Uint8Array(this.alignment);
  }

  get size() {
    return this.writeIndex;
  }

  nextAlignment(length: number) {
    return Math.ceil(length / this.alignment) * this.alignment;
  }

  ensureAvailable(byteLength: number) {
    if (this.writeIndex + byteLength > this.buffer.length) {
      let newLength = this.buffer.length + this.nextAlignment(byteLength);
      const newBuffer = new Uint8Array(newLength);
      newBuffer.set(this.buffer);
      this.buffer = newBuffer;
    }
  }

  get uint8Buffer() {
    return new Uint8Array(
      this.buffer.buffer,
      this.buffer.byteOffset,
      this.size
    );
  }
  getBuffer() {
    return this.buffer;
  }

  writeFloat32(value: number) {
    this.ensureAvailable(4);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setFloat32(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 4;
  }

  writeFloat64(value: number) {
    this.ensureAvailable(8);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setFloat64(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 8;
  }

  writeInt8(value: number) {
    this.ensureAvailable(1);
    this.buffer[this.writeIndex] = value;
    this.writeIndex += 1;
  }

  writeUint8(value: number) {
    this.ensureAvailable(1);
    this.buffer[this.writeIndex] = value;
    this.writeIndex += 1;
  }

  writeInt16(value: number) {
    this.ensureAvailable(2);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setInt16(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 2;
  }

  writeUint16(value: number) {
    this.ensureAvailable(2);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setUint16(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 2;
  }

  writeInt32(value) {
    this.ensureAvailable(4);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setInt32(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 4;
  }

  writeUint32(value: number) {
    this.ensureAvailable(4);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setUint32(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 4;
  }

  writeInt64(value: bigint) {
    this.ensureAvailable(8);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setBigInt64(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 8;
  }

  writeUint64(value: bigint) {
    this.ensureAvailable(8);
    const view = new DataView(this.buffer.buffer, this.buffer.byteOffset);
    view.setBigUint64(this.writeIndex, value, this.endian === Endian.Little);
    this.writeIndex += 8;
  }

  write(bytes: Uint8Array, length?: number) {
    length = length ? length : bytes.length;
    this.ensureAvailable(length);
    this.buffer.set(bytes, this.writeIndex);
    this.writeIndex += length;
  }

  writeVarUint(value: number) {
    let size = Math.ceil(value.toString(2).length / 7);
    let index = 0;
    let i = 0;
    while (i < size) {
      let part = value & 0x7f;
      value >>= 7;
      this.variableEncodeList[index++] = part;
      i += 1;
    }
    for (let i = 0; i < index - 1; i++) {
      this.variableEncodeList[i] |= 0x80;
    }
    this.write(this.variableEncodeList.subarray(0, index));
  }

  writeString(value: string, explicitLength: boolean = true) {
    const encoder = new TextEncoder();
    const bytes = encoder.encode(value);
    if (explicitLength) {
      this.writeVarUint(bytes.length);
    }
    this.write(bytes);
  }
}