@ton3/liteclient/src/tl/stream/stream-writer.ts

TON Blockchain LiteClient

import { Utils } from 'ton3-core'
import { uintToBytes } from './utils'
import { TLBoolean } from '../types/boolean'

export class StreamWriter {
    private _buffer = new ArrayBuffer(0)

    private concat (values: ArrayBuffer[]): ArrayBuffer {
        const length = values.reduce((acc, el) => acc += el.byteLength, 0)
        const { temp } = values.reduce((acc, el) => {
            acc.temp.set(new Uint8Array(el), acc.offset)

            return { temp: acc.temp, offset: acc.offset += el.byteLength }
        }, { temp: new Uint8Array(length), offset: 0 })

        return temp.buffer
    }

    private append (value: ArrayBuffer): this {
        this._buffer = this.concat([ this._buffer, value ])

        return this
    }

    private view (size: number): DataView {
        const buffer = new ArrayBuffer(size)

        return new DataView(buffer)
    }

    public writeBytes (value: Uint8Array): this {
        const lengthSize = value.length < 254 ? 1 : 4
        const paddingSize = 4 - (((lengthSize + value.length) % 4) || 4)
        const buffer = new Uint8Array(lengthSize + value.length + paddingSize).fill(0)

        if (value.length < 254) {
            buffer.set([ value.length ], 0)
        } else {
            buffer.set([ 0xfe ], 0)
            // Write 3 bytes number in little-endian order
            buffer.set(uintToBytes(value.length, 3).reverse(), 1)
        }

        buffer.set(value, lengthSize)
        this.append(buffer.buffer)

        return this
    }

    public writeBuffer (value: Uint8Array): this {
        this.append(value)

        return this
    }

    public writeBool (value: boolean): this {
        this.writeUint32LE(value ? TLBoolean.TRUE : TLBoolean.FALSE)

        return this
    }

    public writeUint8 (value: number): this {
        const view = this.view(1)

        view.setUint8(0, value)
        this.append(view.buffer)

        return this
    }

    public writeInt32LE (value: number): this {
        const view = this.view(4)

        view.setInt32(0, value, true)
        this.append(view.buffer)

        return this
    }

    public writeUint32LE (value: number): this {
        const view = this.view(4)

        view.setUint32(0, value, true)
        this.append(view.buffer)

        return this
    }

    public writeInt64LE (value: bigint): this {
        const view = this.view(8)

        view.setBigInt64(0, value, true)
        this.append(view.buffer)

        return this
    }

    public writeUint64LE (value: bigint): this {
        const view = this.view(8)

        view.setBigUint64(0, value, true)
        this.append(view.buffer)

        return this
    }

    public writeInt128 (value: string | Uint8Array): this {
        const buffer = new Uint8Array(16).fill(0)
        const bytes = typeof value === 'string'
            ? Utils.Helpers.hexToBytes(value)
            : value

        buffer.set(bytes, 0)
        this.append(buffer.buffer)

        return this
    }

    public writeInt256 (value: string | Uint8Array): this {
        const buffer = new Uint8Array(32).fill(0)
        const bytes = typeof value === 'string'
            ? Utils.Helpers.hexToBytes(value)
            : value

        buffer.set(bytes, 0)
        this.append(buffer.buffer)

        return this
    }

    get buffer (): Uint8Array {
        return new Uint8Array(this._buffer)
    }
}