ExtraNonceGenerator

ExtraNonceGenerator.js

function packUInt32BE(num) {
    const buff = new Buffer(4);
    buff.writeUInt32BE(num, 0);
    return buff;
}

function pad(n, v, i  = '0') {
    return v.length < n ? new Array(n - v.length).fill(i).join('') + v : v
}

function mask32(num, [i, j]) {
    const mask = ['00', '00', '00', '00'];
    
    num = leftPad(4, num);

    mask[i] = num.slice(0, 2)
    mask[j] = num.slice(2)

    return parseInt(mask.join(''), 16)
}

function ExtraNonceGenerator(instanceId) {
    const map = [
        [0, 1],
        [0, 2],
        [0, 3],
        [0, 4],
        [1, 2],
        [1, 3],
        [1, 4],
        [2, 3],
        [2, 4],
        [3, 4]
    ]

    this.prev = 1
    this.bytes = map[instanceId % map.length]

    this.next = function extraNonce() {
        var value = mask32(this.prev.toString(16), this.bytes)
        this.prev ++
        return packUInt32BE(value)
    }
}