@uk/tool/src/binbuffer.ts

Uk tools module

export interface BinBuffer {
    index: number;
    packedBitCount: number;
    source: Buffer;
    packetReadNext: boolean;
    readUInt8(offset?: number, noAssert?: boolean): number;
    readUInt16LE(offset?: number, noAssert?: boolean): number;
    readUInt16BE(offset?: number, noAssert?: boolean): number;
    readUInt32LE(offset?: number, noAssert?: boolean): number;
    readUInt32BE(offset?: number, noAssert?: boolean): number;
    readInt8(offset?: number, noAssert?: boolean): number;
    readInt16LE(offset?: number, noAssert?: boolean): number;
    readInt16BE(offset?: number, noAssert?: boolean): number;
    readInt32LE(offset?: number, noAssert?: boolean): number;
    readInt32BE(offset?: number, noAssert?: boolean): number;
    readPackedInt(offset?: number, noAssert?: boolean): number;

    writeUInt8(value: number, offset?: number, noAssert?: boolean): number;
    writeUInt16LE(value: number, offset?: number, noAssert?: boolean): number;
    writeUInt16BE(value: number, offset?: number, noAssert?: boolean): number;
    writeUInt32LE(value: number, offset?: number, noAssert?: boolean): number;
    writeUInt32BE(value: number, offset?: number, noAssert?: boolean): number;
    writeInt8(value: number, offset?: number, noAssert?: boolean): number;
    writeInt16LE(value: number, offset?: number, noAssert?: boolean): number;
    writeInt16BE(value: number, offset?: number, noAssert?: boolean): number;
    writeInt32LE(value: number, offset?: number, noAssert?: boolean): number;
    writeInt32BE(value: number, offset?: number, noAssert?: boolean): number;
    writeFloatLE(value: number, offset?: number, noAssert?: boolean): number;
    writeFloatBE(value: number, offset?: number, noAssert?: boolean): number;
    writeDoubleLE(value: number, offset?: number, noAssert?: boolean): number;
    writeDoubleBE(value: number, offset?: number, noAssert?: boolean): number;
}

function createReader(func: Function, byteCount: number) {
    return function(this: BinBuffer, idx?: number, noassert?: boolean): number {
        const noidx = idx === undefined;
        const rv = func.call(this.source, noidx ? this.index : idx, noassert);
        if (noidx) this.index += byteCount;
        return rv;
    }
}

function createWriter(func: Function, byteCount: number) {
    return function(this: BinBuffer, value?: any, idx?: number, noassert?: boolean): number {
        const noidx = idx === undefined;
        const rv = func.call(this.source, value, noidx ? this.index : idx, noassert);
        if (noidx) this.index += byteCount;
        return rv;
    }
}

export const BinBuffer: { new(buffer: Buffer, index?: number): BinBuffer } = function BinBuffer(this: BinBuffer, buffer: Buffer, index?: number) {
    this.source = buffer;
    this.index = index || 0;
} as any;

for (const n in Buffer.prototype) {
    const member = Buffer.prototype[n] as any;
    if (member instanceof Function) {
        let func;
        switch (n) {
            case 'readUInt8':
            case 'readInt8':
                func = createReader(member, 1);
                break;
            case 'readUInt16LE':
            case 'readUInt16BE':
            case 'readInt16LE':
            case 'readInt16BE':
                func = createReader(member, 2);
                break;
            case 'readUInt32LE':
            case 'readUInt32BE':
            case 'readInt32LE':
            case 'readInt32BE':
                func = createReader(member, 4);
                break;

            case 'writeUInt8':
            case 'writeInt8':
                func = createWriter(member, 1);
                break;
            case 'writeUInt16LE':
            case 'writeUInt16BE':
            case 'writeInt16LE':
            case 'writeInt16BE':
                func = createWriter(member, 2);
                break;
            case 'writeUInt32LE':
            case 'writeUInt32BE':
            case 'writeInt32LE':
            case 'writeInt32BE':
                func = createWriter(member, 4);
                break;
            default:
                func = function(this: BinBuffer) {
                    member.apply(this.source, arguments);
                }
                break;
        }
        BinBuffer.prototype[n] = func;
    } else {
        BinBuffer.prototype[n] = member;
    }
}

BinBuffer.prototype.readPackedInt = function(this: BinBuffer, offset?: number, noAssert?: boolean): number {
    if (offset !== undefined && offset >= 0) this.index = +offset;
    let rv = 0, byte = 0, idx = 0;
    this.packetReadNext = false;
    this.packedBitCount = 0;
    do {
        byte = this.source.readUInt8(this.index++);
        rv = rv << 7 | byte & 0x7F;
        this.packedBitCount += 7;
    } while (byte & 0x80 && idx++ < 4);
    this.packetReadNext = (byte & 0x80) !== 0;
    return rv;
}