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DataBuffer

The DataBuffer class is a wrapper around DataView that adds functionality for cursor tracking, automatic buffer expansion, and more.

Tip

DataBuffer automatically adjusts the cursor position during writes and reads. In practice, when creating custom types, you don’t need to worry about it.

Usage

index.ts
import { DataBuffer } from "encodexx";


const buf = new DataBuffer();


buf.writeFloat64(12.4325);


buf.resetCursor();


console.log(buf.readFloat64());

Danger

Do not use resetCursor on DataBuffer instances obtained while creating custom types. This may lead to serialization errors and data corruption.

Use Cases

Encodexx returns a DataBuffer as a buffer for data serialization and deserialization. You can also use it to create custom types that interact directly with the buffer.

Creating a DataBuffer from an ArrayBuffer

You can pass an ArrayBuffer to the class constructor.

fetch.ts
import { DataBuffer } from "encodexx";
import { serializer } from "./schema.ts";


const arrayBuffer = new ArrayBuffer(200);
// Do something with arrayBuffer
const buffer = new DataBuffer(arrayBuffer);

Sending DataBuffer Over the Network

To send a DataBuffer over the network, you need to convert it into an ArrayBuffer or Uint8Array.

client.ts
import { serializer } from "./schema.ts";
const body = serializer.encode(data).buffer; // Obtaining the ArrayBuffer


fetch(url, {
  method: "POST",
  body,
  headers: {
    // Indicate that binary data is being sent
    "Content-Type": "application/octet-stream",
  },
});

To send data from a server (for example, using Express), use Node.js’s built-in Buffer class:

server.ts
import { serializer, getResponse } from "./schema.ts";


app.post("/", (req, res) => {
  const response = getResponse();


  // Obtain the result as a Uint8Array and convert it to a Buffer
  const encoded = Buffer.from(serializer.encode(response).uint8Array);


  res.set("Content-Type", "application/octet-stream");
  res.send(encoded);
});

API

  • constructor(newBuffer?: ArrayBuffer, size?: number) - Constructor for a new instance. You can specify an initial buffer or initial size.

By default, DataBuffer allocates 1 KB initially and increases in size as needed. You can change this value:

new DataBuffer(undefined, 1024 * 1024); // Immediately allocates 1 MB

Info

Encodexx automatically trims the buffer to the required size.

  • get length(): number; - Gets the length of the used portion of the buffer.
  • get buffer(): ArrayBuffer; - Retrieves the used portion of the buffer.
  • get uint8Array(): Uint8Array; - Retrieves the used portion of the buffer as Uint8Array.
  • get cursor(): number; - Gets the current cursor position.
  • resetCursor(): void; - Resets the cursor position to 0.
  • writeBuffer(buffer: ArrayBuffer | Uint8Array): void; - Writes an ArrayBuffer or Uint8Array of arbitrary length.
  • readBuffer(length: number): ArrayBuffer; - Reads an ArrayBuffer of the specified length.
  • writeUleb128(value: bigint): void; - Writes a number in uleb128 format.
  • readUleb128(): bigint; - Reads a number in uleb128 format.
  • writeSleb128(value: bigint): void; - Writes a number in sleb128 format.
  • readSleb128(): bigint; - Reads a number in sleb128 format.
  • writeInt8(val: number): void; - Writes a number in int8 format.
  • readInt8(): number; - Reads a number in int8 format.
  • writeUint8(val: number): void; - Writes a number in uint8 format.
  • readUint8(): number; - Reads a number in uint8 format.
  • writeInt16(val: number): void; - Writes a number in int16 format.
  • readInt16(): number; - Reads a number in int16 format.
  • writeUint16(val: number): void; - Writes a number in uint16 format.
  • readUint16(): number; - Reads a number in uint16 format.
  • writeInt32(val: number): void; - Writes a number in int32 format.
  • readInt32(): number; - Reads a number in int32 format.
  • writeUint32(val: number): void; - Writes a number in uint32 format.
  • readUint32(): number; - Reads a number in uint32 format.
  • writeFloat32(val: number): void; - Writes a number in float32 format.
  • readFloat32(): number; - Reads a number in float32 format.
  • writeFloat64(val: number): void; - Writes a number in float64 format.
  • readFloat64(): number; - Reads a number in float64 format.
  • writeBigInt64(val: bigint): void; - Writes a number in bigint64 format.
  • readBigInt64(): bigint; - Reads a number in bigint64 format.
  • writeBigUint64(val: bigint): void; - Writes a number in biguint64 format.
  • readBigUint64(): bigint; - Reads a number in biguint64 format.
  • writeString(val: string): void; - Writes a string.
  • readString(): string;- Reads a string.
  • writeBoolean(val: boolean): void; - Writes a boolean value: FF for true and 00 for false.
  • readBoolean(): boolean; - Reads a boolean value.
  • writeDate(val: Date): void; - Writes a date.
  • readDate(): Date; - Reads a date.