Convert 6 array-bytes to int64 using PHP - php

Question

I'm reverse engineering a javascript script to PHP and there are many functions that convert:
6 array bytes of [224, 221, 199, 147, 195, 47]
and output that to 1632933900000 (which is timestamp, Int64)
Can you help me how to pack/unpack those bytes as above to the final integer using PHP ?
Samples:
[224, 221, 199, 147, 195, 47] gets to 1632933900000
[224, 143, 228, 137, 198, 47]
gets to 1633718700000
ADDITIONAL INFO:
The javascript code is very long (it was obfuscated). I just know for certain that it is placed within 6 bytes.
NEXT UPDATE...
It goes to this function (this.buf is array-bytes):
function u() {
var e = new a(0, 0),
t = 0;
if (!(this.len - this.pos > 4)) {
for (; t < 3; ++t) {
if (this.pos >= this.len) throw s(this);
if (e.lo = (e.lo | (127 & this.buf[this.pos]) << 7 * t) >>> 0, this.buf[this.pos++] < 128) return e
}
return e.lo = (e.lo | (127 & this.buf[this.pos++]) << 7 * t) >>> 0, e
}
for (; t < 4; ++t)
if (e.lo = (e.lo | (127 & this.buf[this.pos]) << 7 * t) >>> 0, this.buf[this.pos++] < 128) return e;
if (e.lo = (e.lo | (127 & this.buf[this.pos]) << 28) >>> 0, e.hi = (e.hi | (127 & this.buf[this.pos]) >> 4) >>> 0, this.buf[this.pos++] < 128) return e;
if (t = 0, this.len - this.pos > 4) {
for (; t < 5; ++t)
if (e.hi = (e.hi | (127 & this.buf[this.pos]) << 7 * t + 3) >>> 0, this.buf[this.pos++] < 128) return e
} else
for (; t < 5; ++t) {
if (this.pos >= this.len) throw s(this);
if (e.hi = (e.hi | (127 & this.buf[this.pos]) << 7 * t + 3) >>> 0, this.buf[this.pos++] < 128) return e
}
throw Error("invalid varint encoding")
}
And then it has [hi and low] numbers and this gets the timestamp:
o.prototype.toNumber = function(e) {
if (!e && this.hi >>> 31) {
var t = 1 + ~this.lo >>> 0,
n = ~this.hi >>> 0;
return t || (n = n + 1 >>> 0), -(t + 4294967296 * n)
}
return this.lo + 4294967296 * this.hi
}

Answer 1

224 221 199 147 195 47 is the decimal representation of E0 DD C7 93 C3 2F ... which is 247243140743983 in decimal. Maybe not the whole dword is the timestamp ...for comparision: 01 7C 32 71 EE E0 or 61 54 98 0C. One can already notice by the first digit, how far off this approach is.
That number in JS might be of type BigInt:
BigInt("0x017C3271EEE0")
But BigInt("0xE0DDC793C32F") still gives 247243140743983.

Answer 2

Just to complete this answer I used following stuff, but I have absolutely no clue what it does :D
<?php
function int64_helper($obj)
{
$e = (object) ['lo' => 0, 'hi' => 0];
if (!($obj->len - $obj->pos > 4)) {
for ($i = 0; $i < 3; $i++) {
if ($obj->pos >= $obj->len) throw new Exception('ERROR RANGE');
$e->lo = rrr($e->lo | ((127 & $obj->buf[$obj->pos]) << (7 * $i)), 0);
if ($obj->buf[$obj->pos++] < 128) return $e;
}
$e->lo = rrr($e->lo | ((127 & $obj->buf[$obj->pos++]) << (7 * $i)), 0);
return $e;
}
for ($i = 0; $i < 4; $i++) {
$e->lo = rrr($e->lo | ((127 & $obj->buf[$obj->pos]) << (7 * $i)), 0);
if ($obj->buf[$obj->pos++] < 128) return $e;
}
$e->lo = rrr(($e->lo | ((127 & $obj->buf[$obj->pos]) << 28)), 0);
$e->hi = rrr(($e->hi | rr((127 & $obj->buf[$obj->pos]), 4)), 0);
if ($obj->buf[$obj->pos++] < 128) {
return $e;
}
if ($obj->len - $obj->pos > 4) {
for ($i = 0; $i < 5; $i++) {
$e->hi = rrr($e->hi | ((127 & $obj->buf[$obj->pos]) << (7 * $i) + 3), 0);
if ($obj->buf[$obj->pos++] < 128) return $e;
}
}
else {
for ($i = 0; $i < 5; $i++) {
if ($obj->pos >= $obj->len) throw new Exception('ERROR RANGE');
$e->hi = rrr($e->hi | ((127 & $obj->buf[$obj->pos]) << (7 * $i) + 3), 0);
if ($obj->buf[$obj->pos++] < 128) return $e;
}
}
throw new Exception("invalid timestamp encoding");
}
/**
* Date time
*/
function int64($obj)
{
$e = int64_helper($obj);
$mst = $e->lo + 4294967296 * $e->hi;
$t = substr($mst, 0, -3); // poslední 3 nuly dávám pryč
$s = date("Y-m-d H:i:s", $t); // prague timezone
return $s;
}
/**
* The >>> javascript operator in php x86_64
* Usage: -1149025787 >>> 0 ---> rrr(-1149025787, 0) === 3145941509
* #return int
*/
function rrr($v, $n)
{
return ($v & 0xFFFFFFFF) >> ($n & 0x1F);
}
/**
* The >> javascript operator in php x86_64
* #return int
*/
function rr($v, $n)
{
return ($v & 0x80000000 ? $v | 0xFFFFFFFF00000000 : $v & 0xFFFFFFFF) >> ($n & 0x1F);
}
/**
* The << javascript operator in php x86_64
* #return int
*/
function ll($v, $n)
{
return ($t = ($v & 0xFFFFFFFF) << ($n & 0x1F)) & 0x80000000 ? $t | 0xFFFFFFFF00000000 : $t & 0xFFFFFFFF;
}