mrsuh / php-var-sizeof
Provides functions for getting full size of any PHP variable
Installs: 3 613
Dependents: 1
Suggesters: 0
Security: 0
Stars: 60
Watchers: 2
Forks: 1
Open Issues: 0
Requires
- php: >=7.4
- ext-ffi: *
Requires (Dev)
- maddhatter/markdown-table: ^1.0
- phpunit/phpunit: ^9
This package is auto-updated.
Last update: 2025-03-13 22:03:59 UTC
README
Function for getting size of any PHP variable in bytes.
It must be more accurate tool to calculate total size of PHP variable than memory_get_usage()
, but it has restrictions.
How it works
var_sizeof()
with var_class_sizeof()
uses FFI to access internal structures of PHP variables.
It calculates the size of internal structures such as zval
, _zend_array
, _zend_object
, etc., as well as additional allocated memory for them.
It doesn't take into calculate the memory of handlers/functions/etc.
Requirements
- PHP >= 7.4 (with FFI)
- Linux(x86_64/aarch64) / Darwin(x86_64/arm64)
How to install
composer require mrsuh/php-var-sizeof
Functions
int var_sizeof(mixed $var);
int var_class_sizeof(mixed $var);
Usage
<?php require_once __DIR__ . '/vendor/autoload.php'; $int = 1; printf("variable \$int size: %d bytes\n", var_sizeof($int)); $array = array_fill(0, 100, $a); printf("variable \$array size: %d bytes\n", var_sizeof($array)); $object = new \stdClass(); printf("variable \$object size: %d bytes\n", var_sizeof($object)); printf("class \$object size: %d bytes\n", var_class_sizeof($object));
var_sizeof vs memory_get_usage
PHP 8.1.2 Linux(x86_64)
type | var_sizeof(bytes) | memory_get_usage(bytes) |
---|---|---|
NULL | 16 | 0 |
boolean(true) | 16 | 0 |
integer(1) | 16 | 0 |
double(1.5) | 16 | 0 |
string("hello world") | 27 | 40 |
resource | 48 | 416 |
callable | 72 | 384 |
array(count: 0, list: true) | 336 | 0 |
array(count: 100, list: true) | 2,128 | 8,248 |
array(count: 1,000, list: true) | 16,464 | 36,920 |
array(count: 10,000, list: true) | 262,224 | 528,440 |
array(count: 100, list: false) | 5,192 | 8,248 |
array(count: 1,000, list: false) | 41,032 | 41,016 |
array(count: 10,000, list: false) | 655,432 | 655,416 |
EmptyClass{} | 72 | 40 |
ClassWithArray{"array(count: 0, list: true)"} | 408 | 56 |
ClassWithArray{"array(count: 100, list: true)"} | 2,200 | 8,304 |
ClassWithArray{"array(count: 1,000, list: true)"} | 16,536 | 36,976 |
ClassWithArray{"array(count: 10,000, list: true)"} | 262,296 | 528,496 |
ClassWithObject{"EmptyClass{}"} | 144 | 96 |
ArrayIterator{"array(count: 100, list: true)"} | 2,264 | 8,376 |
ArrayIterator{"array(count: 100, list: false)"} | 5,328 | 40,376 |
type | var_class_sizeof(bytes) | var_sizeof(bytes) | memory_get_usage(bytes) |
---|---|---|---|
EmptyClass{} | 1,362 | 72 | 40 |
ClassWithArray{"array(count: 0, list: true)"} | 1,494 | 408 | 56 |
ClassWithArray{"array(count: 100, list: true)"} | 1,494 | 2,200 | 8,304 |
ClassWithArray{"array(count: 1,000, list: true)"} | 1,494 | 16,536 | 36,976 |
ClassWithArray{"array(count: 10,000, list: true)"} | 1,494 | 262,296 | 528,496 |
ClassWithObject{"EmptyClass{}"} | 1,495 | 144 | 96 |
ArrayIterator{"array(count: 100, list: true)"} | 2,437 | 2,264 | 8,376 |
ArrayIterator{"array(count: 100, list: false)"} | 2,437 | 5,328 | 40,376 |
⚠️ Restrictions
- works correctly only with userland objects and SPL \ArrayIterator
- doesn't work correctly with complicated structures like extensions/resources/callables/functions
- to calculate total size of an object you need to use
var_sizeof()
withvar_class_sizeof()
For contributors
How to reproduce a table of numbers above
git clone --recurse-submodules git@github.com:mrsuh/php-var-sizeof.git && cd php-var-sizeof composer install docker build -t image-php-var-sizeof . docker run -it --rm --name my-running-script -v "$PWD":/app image-php-var-sizeof php bin/render-table.php
How to compile library
git submodule update --init --recursive cd php-src ./buildconf ./configure --with-ffi --with-iconv=/opt/homebrew/opt/libiconv cd .. make DEBUG=1
docker build -t php-var-sizeof -f Dockerfile-compile . docker run -it -v $(pwd)/library:/code/library php-var-sizeof bash cd /code make DEBUG=1