PHP, how to get every possible byte sequence in range? - php

Question

i want every possible byte sequence between range(x,y), like range(0,0xFFFF) would give me 00...FF.0000.0001...FFFF ~
this works, but i suspect there's a much easier way to do it which escapes me, any suggestions?
<?php
function incbinstring(string $str): string
{
/*
if(strlen($str)===0){
return "\x00";
}
*/
$scanCurrent = strlen($str) - 1;
while ($scanCurrent >= 0) {
if ($str[$scanCurrent] !== "\xFF") {
break;
}
--$scanCurrent;
}
if ($scanCurrent < 0) {
// they're all \xFF... add new byte and all zeroes
return str_repeat("\x00", strlen($str) + 1);
}
if ($scanCurrent !== strlen($str) - 1) {
// preceeded by a bunch of \xFF\xFF\xFF , zero them out
// ps, this can be optimized to a substr()+str_repeat()
for ($i = strlen($str) - 1; $i > $scanCurrent; --$i) {
$str[$i] = "\x00";
}
}
// increment the first non-\xFF with 1
$str[$scanCurrent] = chr(ord($str[$scanCurrent]) + 1);
return $str;
}
$str = "\x00";
for ($i = 0; $i < 0xFFFF + 600; ++$i) {
echo bin2hex($str),"\n";
$str = incbinstring($str);
}
outputs, in part
00
01
02
03
04
05
06
07
(...)
f3
f4
f5
f6
f7
f8
f9
fa
fb
fc
fd
fe
ff
0000
0001
0002
0003
0004
(...)
fffb
fffc
fffd
fffe
ffff
000000
000001
000002
000003
000004
000005
000006
000007

Answer 1

<?php
function counterHex ($fromHex, $toHex ) {
$fromDec = hexdec($fromHex);
$toHex = hexdec($toHex);
for ($i = $fromHex; $i< $toHex; $i++){
echo dechex($i) .", ";
}
}
counterHex(1,'ff');
see: http://sandbox.onlinephpfunctions.com/code/d70d2766297c32039e01dd868e791b476bc92a87