octdec

cubbo at quakenet dot php (2009-02-18 05:49:52)

Hi, this is an attempt to explain octdec(). 

There is one bug, if input is not octal, it doesn't return a proper decimal.

<?php 

$octal = (int) "764";

function octal_to_decimal($int)
    {                
        $data = integer;
        $i = (strlen($int) - 1);    
        $parse_int = str_split($int);
        foreach($parse_int as $value)
            {
                $data += (int)($value * pow(8, $i));
                $i--;
            }        
        return $data;
    }
/**
*    explanation of the PHP function octdec()
*/
print octal_to_decimal($octal) . "<br />";

/**
*    the PHP function octdec()
*/
print octdec($octal);

?>

contato at andersonfraga dot net (2008-08-18 13:30:10)

Number is octal?

Simple and easy:

<?php

function is_octal($x) {
    return decoct(octdec($x)) == $x;
}

echo is_octal(077); // true
echo is_octal(195); // false

?>

Thanks
[]'s

harry at disgruntledgoat dot com (2007-03-27 03:03:29)

Calling the sticky bit "text" is not erroneous: On UNIX back in 1974, it instructed the operating system to retain the text segment of the program in swap space after the process exited. This speeded subsequent executions by allowing the kernel to make a single operation of moving the program from swap to real memory.

(2002-09-11 01:51:28)

The 'S' flag for Unix file access rights is badly computed in the above sample.
If the corresponding 'x' bit (exec) is not set, and the 's' bit (setgid/setuid/sticky) is set, then the flag should not be displayed as and uppercase 'S', but as a lower case 's'. Also the sticky bit (mainly used for folders with public right access rights such as /tmp to protect against deletion by non owner) is badly named ("text"?).

meheler at searchbc dot com (2001-10-25 20:03:38)

This function and decoct work great when working with file permissions. For example:

<?php
    $mode = octdec('4750');
    
    $user['suid']     = ($mode & 04000);
    $user['read']     = ($mode & 00400);
    $user['write']    = ($mode & 00200);
    $user['execute']  = ($mode & 00100);
    
    $group['sgid']    = ($mode & 02000);
    $group['read']    = ($mode & 00040);
    $group['write']   = ($mode & 00020);
    $group['execute'] = ($mode & 00010);
    
    $other['text']    = ($mode & 01000);
    $other['read']    = ($mode & 00004);
    $other['write']   = ($mode & 00002);
    $other['execute'] = ($mode & 00001);
    
    $attrs = array('-','-','-','-','-','-','-','-','-','-');
    
    if ($system['dir']) $attrs[0] = 'd';
    
    if ($user['read']) $attrs[1] = 'r';
    if ($user['write']) $attrs[2] = 'w';
    if ($user['execute']) $attrs[3] = 'x';
    if ($user['suid']) $attrs[3] = 'S';
    
    if ($group['read']) $attrs[4] = 'r';
    if ($group['write']) $attrs[5] = 'w';
    if ($group['execute']) $attrs[6] = 'x';
    if ($group['sgid']) $attrs[6] = 'S';

    if ($other['read']) $attrs[7] = 'r';
    if ($other['write']) $attrs[8] = 'w';
    if ($other['execute']) $attrs[9] = 'x';
    if ($other['text']) $attrs[9] = 'T';
    
    echo '<pre>';
    echo 'Mode Decimal: ' . $mode . "\n";
    echo 'Mode Octal: ' . decoct($mode) . "\n";
    echo 'Mode String: ' . implode('',$attrs)."\n";
    echo '</pre>';
?>

Outputs:

Mode Decimal: 2536
Mode Octal: 4750
Mode String: -rwSr-x---

-Mike