another version of return_bytes which returns faster and does not use multiple multiplications (sorry:). even if it is resolved at compile time it is not a good practice;
no local variables are allocated;
the trim() is omitted (php already trimmed values when reading php.ini file);
strtolower() is replaced by second case which wins us one more function call for the price of doubling the number of cases to process (may slower the worst-case scenario when ariving to default: takes six comparisons instead of three comparisons and a function call);
cases are ordered by most frequent goes first (uppercase M-values being the default sizes);
specs say we must handle integer sizes so float values are converted to integers and 0.8G becomes 0;
'Gb', 'Mb', 'Kb' shorthand byte options are not implemented since are not in specs, see
http://www.php.net/manual/en/faq.using.php#faq.using.shorthandbytes
<?php
function return_bytes ($size_str)
{
switch (substr ($size_str, -1))
{
case 'M': case 'm': return (int)$size_str * 1048576;
case 'K': case 'k': return (int)$size_str * 1024;
case 'G': case 'g': return (int)$size_str * 1073741824;
default: return $size_str;
}
}
?>
PHP - Manual: ini_get
2024-11-15
ini_get
(PHP 4, PHP 5, PHP 7, PHP 8)
ini_get — 获取一个配置选项的值
说明
ini_get(string
$varname): string成功时返回配置选项的值。
参数
-
varname -
配置选项名称。
返回值
成功是返回配置选项值的字符串，null 的值则返回空字符串。如果配置选项不存在，将会返回 false。
范例
示例 #1 一些 ini_get() 例子
<?php
/*
我们的 php.ini 包含了以下的设置：
display_errors = On
register_globals = Off
post_max_size = 8M
*/
echo 'display_errors = ' . ini_get('display_errors') . "\n";
echo 'register_globals = ' . ini_get('register_globals') . "\n";
echo 'post_max_size = ' . ini_get('post_max_size') . "\n";
echo 'post_max_size+1 = ' . (ini_get('post_max_size')+1) . "\n";
echo 'post_max_size in bytes = ' . return_bytes(ini_get('post_max_size'));
function return_bytes($val) {
$val = trim($val);
$last = strtolower($val[strlen($val)-1]);
switch($last) {
// 自 PHP 5.1.0 起可以使用修饰符 'G'
case 'g':
$val *= 1024;
case 'm':
$val *= 1024;
case 'k':
$val *= 1024;
}
return $val;
}
?>
以上例程的输出类似于：
display_errors = 1 register_globals = 0 post_max_size = 8M post_max_size+1 = 9 post_max_size in bytes = 8388608
注释
注意: 当查询一个 boolean 值
一个
off的 boolean ini 值将会以空字符串或者 "0" 返回；on的 ini 值会以 "1" 返回。 此函数也会返回 INI 值的文字字符串。
注意: 当查询一个内存尺寸的值
许多内存尺寸的 ini 值，类似 upload_max_filesize 是以简写表示法储存在 php.ini 文件里。 ini_get() 会返回 php.ini 文件中储存的确切字符串，而不是它的等量 integer。 尝试对这些值使用常规算术运算函数将不会得到预期的结果。 以上例子显示了转换简写表示法为字节的一种方式，和 PHP 源码所做的比较像。
注意:
ini_get() 无法读取 "array" 的 ini 选项，例如 pdo.dsn.*，在这个例子中会返回
false。
更新日志
| 版本 | 说明 |
|---|---|
| 5.3.0 |
当配置项不存在，之前会返回空字符串，现在会返回 false。
|
参见
- get_cfg_var() - 获取 PHP 配置选项的值
- ini_get_all() - 获取所有配置选项
- ini_restore() - 恢复配置选项的值
- ini_set() - 为一个配置选项设置值
add a note
User Contributed Notes 12 notes
Stas Trefilov, OpteamIS ¶
12 years ago
devsrealmGuy ¶
10 months ago
Here is another way to get the result in bytes using PHP8
<?php
/**
* @param string $size
* @return int
* @author DevsrealmGuy
*/
public function getBytes(string $size): int
{
$size = trim($size);
#
# Separate the value from the metric(i.e MB, GB, KB)
#
preg_match('/([0-9]+)[\s]*([a-zA-Z]+)/', $size, $matches);
$value = (isset($matches[1])) ? $matches[1] : 0;
$metric = (isset($matches[2])) ? strtolower($matches[2]) : 'b';
#
# Result of $value multiplied by the matched case
# Note: (1024 ** 2) is same as (1024 * 1024) or pow(1024, 2)
#
$value *= match ($metric) {
'k', 'kb' => 1024,
'm', 'mb' => (1024 ** 2),
'g', 'gb' => (1024 ** 3),
't', 'tb' => (1024 ** 4),
default => 0
};
return (int)$value;
}
#
# TEST: This default to 0 if it doesn't conform with the match standard
#
echo getBytes('2GB') . "</br>";
# OUTPUT: 2147483648
echo getBytes('4tb') . "</br>";
# OUTPUT: 4398046511104
echo getBytes('5345etrgrfd') . "</br>";
# OUTPUT: 0
echo getBytes('357568336586') . "</br>";
# OUTPUT: 0
?>
IceNV ¶
5 years ago
Be aware that max_execution_time can be altered by XDebug.
While debugging a script locally that made use of <?php ini_get('max_execution_time'); ?> it returned 0 when XDebug remote debugging was enabled and the IDE was listening to it.
It makes sense, since debugging manually takes time so we don't want the script to time out ; but in that particular case, it made it look to the script like max_execution_time was 0, so calculations were wrong.
You can see in phpinfo() that local value is 0 in that case, but master value is the correct one you set in your php.ini.
filh at filh dot org ¶
16 years ago
Concerning the value retourned, it depends on how you set it.
I had the problem with horde-3 which test the safe_mode value.
THan :
- if you set the value with php_admin_value safe_mode Off (or On) ini_get returns the string
- if you set the value with php_admin_flag safe_mode Off (or On) ini_get returns the boolean.
peter ¶
13 years ago
The above example function called return_bytes() assumes that ini_get('upload_max_filesize') delivers only one letter at the end. As I've seen 'Mb' and things like that, I'd suggest to change the $last = ... part into $last = strtolower(substr($val,strlen($val/1),1)).
I'd call it $unit then.
Ivo Mandalski ¶
10 years ago
This version of return_bytes takes care of the MB, GB, KB cases along with the M,G,K ones.
Hope this is helpful!
<?php
public static function return_bytes ($val)
{
if(empty($val))return 0;
$val = trim($val);
preg_match('#([0-9]+)[\s]*([a-z]+)#i', $val, $matches);
$last = '';
if(isset($matches[2])){
$last = $matches[2];
}
if(isset($matches[1])){
$val = (int) $matches[1];
}
switch (strtolower($last))
{
case 'g':
case 'gb':
$val *= 1024;
case 'm':
case 'mb':
$val *= 1024;
case 'k':
case 'kb':
$val *= 1024;
}
return (int) $val;
}
?>
Joe Huss detain at interserver dot net ¶
5 months ago
Here is a version combining a few of the examples here that does *not* require php8 nor does it generate a warning
/**
* gets the value in bytes converted from a human readable string like 10G'
*
* @param mixed $val the human readable/shorthand version of the value
* @return int the value converted to bytes
*/
function return_bytes($val) {
$val = trim($val);
preg_match('/([0-9]+)[\s]*([a-zA-Z]+)/', $val, $matches);
$value = (isset($matches[1])) ? intval($matches[1]) : 0;
$metric = (isset($matches[2])) ? strtolower($matches[2]) : 'b';
switch ($metric) {
case 'tb':
case 't':
$value *= 1024;
case 'gb':
case 'g':
$value *= 1024;
case 'mb':
case 'm':
$value *= 1024;
case 'kb':
case 'k':
$value *= 1024;
}
return $value;
}
bishop@php ¶
6 years ago
Yet another implementation of return_bytes:
<?php
function return_bytes($val)
{
assert('1 === preg_match("/^\d+([kmg])?$/i", $val)');
static $map = array ('k' => 1024, 'm' => 1048576, 'g' => 1073741824);
return (int)$val * @($map[strtolower(substr($val, -1))] ?: 1);
}
?>
If you're using PHP >= 7, you might replace ?: with ?? to avoid the use of the @ silencer.
nicolas dot grekas+php at gmail dot com ¶
12 years ago
Here is how to accurately test for boolean php.ini values:
<?php
function ini_get_bool($a)
{
$b = ini_get($a);
switch (strtolower($b))
{
case 'on':
case 'yes':
case 'true':
return 'assert.active' !== $a;
case 'stdout':
case 'stderr':
return 'display_errors' === $a;
default:
return (bool) (int) $b;
}
}
?>
david dot tulloh at infaze dot com dot au ¶
17 years ago
You can set custom entries in the ini file to provide globals such as database details.
However these must be retrieved with get_cfg_var, ini_get won't work.
bishop at php dot net ¶
6 years ago
In a similar vein, converting flags to booleans proper:
<?php
function return_boolean($val)
{
static $map = array ('on' => true, 'true' => true, 'off' => false, 'false' => false);
return @($map[strtolower($val)] ?: (bool)$val);
}
?>
If you're using PHP >= 7, consider replacing ?: with ?? and removing the @ silencer.
Der Graph ¶
17 years ago
It might be useful for included scripts that include other files to extend the 'include_path' variable:
<?php ini_set('include_path',ini_get('include_path').':../includes:'); ?>
Sometimes, it may also be useful to store the current 'include_path' in a variable, overwrite it, include, and then restore the old 'include_path'.
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