Run results for: Bytes to BigInt64

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:133.0) Gecko/20100101 Firefox/133.0

Browser: Firefox 133

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Loop

2.0M/s

DataView

1.3M/s

View exact numbers

Test name	Executions per second
✓ Loop	1,950,620 Ops/sec
DataView	1,280,657 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

function bytesToBigIntLoop(bytes) {
    let value = 0n;
    let bits = 8n;
    for (let i = 0; i < bytes.length; i++) {
        value = (value << bits) + BigInt(bytes[i]);
    }
    return value;
}

function bytesToBigIntDataView(bytes) {
    const view = new DataView(bytes.buffer);
    return view.getBigInt64(0);
}

function bytesToBigIntHex(bytes) {
    return BigInt('0x' + bytes.map(byte => byte.toString(16).padStart(2, '0')).join(''))
}

function bytesToBigIntLoop2(data) {
    let encoded = 0n;

    for (let i = 0, l = data.length; i < l; i++) {

        encoded |= BigInt(data[i]) << BigInt((l - i - 1) * 8);

    }

    return encoded;

}

function bytesToBigIntSplit(data) {
    let high = 0;
    high = (high << 8) | data[0];
    high = (high << 8) | data[1];
    high = (high << 8) | data[2];
    high = (high << 8) | data[3];

    let low = 0;
    low = (low << 8) | data[4];
    low = (low << 8) | data[5];
    low = (low << 8) | data[6];
    low = (low << 8) | data[7];

    return (BigInt(low) << 32n) | BigInt(high);
}

Tests:

Loop
bytesToBigIntLoop(new Uint8Array([255,255,255,0,0,0,0,0]))
DataView
bytesToBigIntDataView(new Uint8Array([255,255,255,0,0,0,0,0]))
Hex
bytesToBigIntHex(new Uint8Array([255,255,255,0,0,0,0,0]))
Loop2
bytesToBigIntLoop2(new Uint8Array([255,255,255,0,0,0,0,0]))
Split
bytesToBigIntSplit(new Uint8Array([255,255,255,0,0,0,0,0]))