TAR Tape Archive

SIGNATURE = bytes.fromhex("7573746172")
OFFSET = 257

def is_tar(path: str) -> bool:
    with open(path, "rb") as f:
        f.seek(OFFSET)
        head = f.read(len(SIGNATURE))
    return head == SIGNATURE

const SIGNATURE = [0x75, 0x73, 0x74, 0x61, 0x72];
const OFFSET = 257;

// bytes: a Uint8Array / Buffer holding the start of the file
export function isTar(bytes) {
  return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}

package fileid

import "bytes"

var istarSignature = []byte{0x75, 0x73, 0x74, 0x61, 0x72}

const istarOffset = 257

func IsTar(b []byte) bool {
	end := istarOffset + len(istarSignature)
	if len(b) < end {
		return false
	}
	return bytes.Equal(b[istarOffset:end], istarSignature)
}

const SIGNATURE: &[u8] = &[0x75, 0x73, 0x74, 0x61, 0x72];
const OFFSET: usize = 257;

fn is_tar(bytes: &[u8]) -> bool {
    bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}

<?php
$signature = "\x75\x73\x74\x61\x72";
$offset = 257;

function is_tar(string $bytes): bool {
    global $signature, $offset;
    return substr($bytes, $offset, strlen($signature)) === $signature;
}