<?php
function pack_encode($val) {
$str = '';
while ($val > 0) {
$str .= chr($val & 0xFF);
$val = $val >> 8;
}
// "/" json-encodes poorly and "=" is padding
return str_replace(
array('/', '='),
array('_', ''),
base64_encode($str)
);
}
function pack_decode($bin) {
$str = base64_decode(str_replace('_', '/', $bin));
$val = 0;
for ($i=0; $i<strlen($str); $i++) {
$val |= (ord($str[$i]) << ($i * 8));
}
return $val;
}
for ($i=0; $i<32; $i++) {
$val = 1<<$i;
$enc = pack_encode($val);
$dec = pack_decode($enc);
echo "$val => $enc => $dec\n";
}
/*
$arr = array();
$packed = pack('N', 32767);
for ($i=0; $i<strlen($packed); $i++) {
$arr[$i] = ord($packed[$i]);
}
print_r($arr);
function pack_encode($val) {
$b64 = base64_encode(pack($format, $val));
return str_replace(array('/', '='), array('_', ''), $b64); // "/" json-encodes poorly and "=" is padding
}
function pack_decode($bin) {
$b64 = str_replace('_', '/', $bin); // un-padded
$data = unpack('C'.(length($bin)/2), base64_decode($b64, false));
$val = 0;
foreach ($data as $v) {
$val = ($val<<$width) | $v;
}
return $val;
}
$max = 32767;
$n = 20;
$step = intval($max/$n);
for ($i=0; $i<=$n; $i++) {
$val = $i*$step;
$enc = pack_encode($val);
$dec = pack_decode($val);
echo "$enc $dec $val\n";
}
*/
- Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
- 1 => AQ => 1
2 => Ag => 2
4 => BA => 4
8 => CA => 8
16 => EA => 16
32 => IA => 32
64 => QA => 64
128 => gA => 128
256 => AAE => 256
512 => AAI => 512
1024 => AAQ => 1024
2048 => AAg => 2048
4096 => ABA => 4096
8192 => ACA => 8192
16384 => AEA => 16384
32768 => AIA => 32768
65536 => AAAB => 65536
131072 => AAAC => 131072
262144 => AAAE => 262144
524288 => AAAI => 524288
1048576 => AAAQ => 1048576
2097152 => AAAg => 2097152
4194304 => AABA => 4194304
8388608 => AACA => 8388608
16777216 => AAAAAQ => 16777216
33554432 => AAAAAg => 33554432
67108864 => AAAABA => 67108864
134217728 => AAAACA => 134217728
268435456 => AAAAEA => 268435456
536870912 => AAAAIA => 536870912
1073741824 => AAAAQA => 1073741824
2147483648 => AAAAgA => 2147483648
preferences:
229.33 ms | 407 KiB | 350 Q