Various CRC32 implementations
CRC32 implementations, that support all crc32 polynomials, as well as (if you install the pecl extension) hardware accelerated versions of CRC32C (Castagnoli).
Supports PHP 5.4 though PHP 7.4.
require 'vendor/autoload.php'; use Google\CRC32\CRC32; $crc = CRC32::create(CRC32::CASTAGNOLI); $crc->update('hello'); echo $crc->hash();
Depending on the environment and the polynomial,
CRC32::create will choose
the fastest available version, and return one of the following classes:
Google\CRC32\PHP- A pure PHP implementation.
Google\CRC32\Builtin- A PHP Hash framework implementation.
Google\CRC32\Google- A hardware accelerated implementation (using google/crc32c).
When reading 1M byte chunks, using
CRC32::CASTAGNOLI with PHP 7.4 on a 2014 Macbook Pro we get the following performance (higher is better):
Google\CRC32\PHP 12.27 MB/s Google\CRC32\Builtin 468.74 MB/s (available since PHP 7.4) Google\CRC32\Google 24,684.46 MB/s (using crc32c.so)
$ composer require google/crc32
To use the hardware accelerated, a custom PHP extension must be installed. This makes use of google/crc32c which provides a highly optomised
CRC32C (Castagnoli) implementation using the SSE 4.2 instruction set of Intel CPUs.
The extension can be installed from pecl, or compiled from stratch.
TODO pecl install crc32c
Once installed or compiled, you'll need to add
extension=crc32c.so to your php.ini file.
Simple (using Makefile):
cd ext # Install the google/crc32c library ./install_crc32c.sh # From source (recommended) # or use your favorite package manager, e.g. # brew install crc32c # Prepare the build environment phpize ./configure # or if using a custom crc32c # ./configure --with-crc32c=$(brew --prefix crc32c) ## Build and test make test
The extension will now be at
ext/modules/crc32c.so. This file should be copied to your extension directory and reference in your php.ini.
# php.ini extension=crc32c.so
make test will test with the current PHP.
make test_all will search for available
PHP installs, and test with all of them.
To compare the performance of the different
CRC32C implementations, run
- Test if this works on 32 bit machine.
- Add php unit (or similar) testing.
- Publish to packagist
- Publish to pecl (https://pecl.php.net/account-request.php)
- Update instructions for linux.
This is not an official Google product (experimental or otherwise), it is just code that happens to be owned by Google.
Copyright 2019 Google Inc. All Rights Reserved. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.