parse_ini_string_m is analog for a parse_ini_string function.

had to code this function due to the lack of a php 5.3 on some hosting.

parse_ini_string_m:
- ignores commented lines that start with ";" or "#"
- ignores broken lines that do not have "="
- supports array values and array value keys

<?php
function parse_ini_string_m($str) {
    
    if(empty($str)) return false;

    $lines = explode("\n", $str);
    $ret = Array();
    $inside_section = false;

    foreach($lines as $line) {
        
        $line = trim($line);

        if(!$line || $line[0] == "#" || $line[0] == ";") continue;
        
        if($line[0] == "[" &amp;&amp; $endIdx = strpos($line, "]")){
            $inside_section = substr($line, 1, $endIdx-1);
            continue;
        }

        if(!strpos($line, '=')) continue;

        $tmp = explode("=", $line, 2);

        if($inside_section) {
            
            $key = rtrim($tmp[0]);
            $value = ltrim($tmp[1]);

            if(preg_match("/^\".*\"$/", $value) || preg_match("/^'.*'$/", $value)) {
                $value = mb_substr($value, 1, mb_strlen($value) - 2);
            }

            $t = preg_match("^\[(.*?)\]^", $key, $matches);
            if(!empty($matches) &amp;&amp; isset($matches[0])) {

                $arr_name = preg_replace('#\[(.*?)\]#is', '', $key);

                if(!isset($ret[$inside_section][$arr_name]) || !is_array($ret[$inside_section][$arr_name])) {
                    $ret[$inside_section][$arr_name] = array();
                }

                if(isset($matches[1]) &amp;&amp; !empty($matches[1])) {
                    $ret[$inside_section][$arr_name][$matches[1]] = $value;
                } else {
                    $ret[$inside_section][$arr_name][] = $value;
                }

            } else {
                $ret[$inside_section][trim($tmp[0])] = $value;
            }            

        } else {
            
            $ret[trim($tmp[0])] = ltrim($tmp[1]);

        }
    }
    return $ret;
}
?>

example usage:

<?php
$ini = '

    [simple]
    val_one = "some value"
    val_two = 567

    [array]
    val_arr[] = "arr_elem_one"
    val_arr[] = "arr_elem_two"
    val_arr[] = "arr_elem_three"

    [array_keys]
    val_arr_two[6] = "key_6"
    val_arr_two[some_key] = "some_key_value"

';

$arr = parse_ini_string_m($ini);
?>

variable $arr output:

Array
(
    [simple] => Array
    (
        [val_one] => some value
        [val_two] => 567
    )

    [array] => Array
    (
        [val_arr] => Array
        (
            [0] => arr_elem_one
            [1] => arr_elem_two
            [2] => arr_elem_three
        )
    )

    [array_keys] => Array
    (
        [val_arr_two] => Array
        (
            [6] => key_6
            [some_key] => some_key_value
        )

    )

)

Replacement for php_ini_string() for PHP pre 5.3 - uses php_ini_file() and streams

<?php
if ( !function_exists( 'parse_ini_string' ) ) {
    function parse_ini_string( $string, $process_sections ) {
        if ( !class_exists( 'parse_ini_filter' ) ) {
            /* Define our filter class */
            class parse_ini_filter extends php_user_filter {
                static $buf = '';
                function filter( $in, $out, &$consumed, $closing ) {
                    $bucket = stream_bucket_new( fopen('php://memory', 'wb'), self::$buf );
                    stream_bucket_append( $out, $bucket );
                    return PSFS_PASS_ON;
                }
            }
            /* Register our filter with PHP */
            stream_filter_register("parse_ini", "parse_ini_filter")
            or return false;
        }
        parse_ini_filter::$buf = $string;
        return parse_ini_file( "php://filter/read=parse_ini/resource=php://memory", $process_sections );
    }
}
?>

With function parse_ini_stringM() below you can:
- fix unvalued fields ('key' (invalid) ==> 'key=' (OK) )
- fix unquotted values with equal sign '=' ('key=value_part1=value_part2' ==> 'key="value_part1=value_part2"')
- fix (solve) multidimensional arrays (makes 'key[key1][key2]=value' valid)

function parse_ini_stringM() on github https://gist.github.com/msegu/c43a871c5a874a1d9bff978b448a0aa4 (here is too long)

// Example:

$ini = '[a]
b
c=d
e=';

var_export(parse_ini_string($ini, TRUE)); /* array (
  'a' => 
  array (
    'c' => 'd',
    'e' => '',
  ),
)
*/

$ini .= '
f[g][2]=h
f[g][i]=j
f[g][][]=k
m=n=o';

var_export(parse_ini_string($ini, TRUE)); // false

var_export(parse_ini_stringM($ini, TRUE)); /* array (
  'a' => 
  array (
    'b' => '',
    'c' => 'd',
    'e' => '',
    'f' => 
    array (
      'g' => 
      array (
        2 => 'h',
        'i' => 'j',
        3 => 
        array (
          0 => 'k',
        ),
      ),
    ),
    'm' => 'n=o',
  ),
)
*/

Hi,
Up to PHP 8.3 (at least), it seems that INI_SCANNER_TYPED is ignored when trying to get values from constants.
For example :
<?php
// https://3v4l.org/qK5o8

const OK = true;
const KO = false;
const NIL = null;

$ini = <<<'INI'
a = TRUE
b = FALSE
c = null
d = 9223372036854775807
INI;
var_dump(parse_ini_string($ini, false, INI_SCANNER_NORMAL), parse_ini_string($ini, false, INI_SCANNER_TYPED));
$ini = <<<'INI'
a = OK
b = KO
c = NIL
d = PHP_INT_MAX
INI;
var_dump(parse_ini_string($ini, false, INI_SCANNER_NORMAL), parse_ini_string($ini, false, INI_SCANNER_TYPED));
?>

I thought it was worth mentioning.