VIII. PHP bytecode Compiler

Introduction

Warning

This extension is EXPERIMENTAL. The behaviour of this extension -- including the names of its functions and anything else documented about this extension -- may change without notice in a future release of PHP. Use this extension at your own risk.

Bcompiler was written for several reasons:

To encode entire script in a proprietary PHP application

To encode some classes and/or functions in a proprietary PHP application

To enable the production of php-gtk applications that could be used on client desktops, without the need for a php.exe.

To do the feasibility study for a PHP to C converter

The first of these goals is achieved using the bcompiler_write_header(), bcompiler_write_file() and bcompiler_write_footer() functions. The bytecode files can be written as either uncompressed or plain. To use the generated bytecode, you can simply include it with include or require statements.

The second of these goals is achieved using the bcompiler_write_header(), bcompiler_write_class(), bcompiler_write_footer(), bcompiler_read(), and bcompiler_load() functions. The bytecode files can be written as either uncompressed or plain. The bcompiler_load() reads a bzip compressed bytecode file, which tends to be 1/3 of the size of the original file.

To create EXE type files, bcompiler has to be used with a modified sapi file or a version of PHP which has been compiled as a shared library. In this scenario, bcompiler reads the compressed bytecode from the end of the exe file.

bcompiler can improve performance by about 30% when used with uncompressed bytecodes only. But keep in mind that uncompressed bytecode can be up to 5 times larger than the original source code. Using bytecode compression can save your space, but decompression requires much more time than parsing a source. bcompiler also does not do any bytecode optimization, this could be added in the future...

In terms of code protection, it is safe to say that it would be impossible to recreate the exact source code that it was built from, and without the accompanying source code comments. It would effectively be useless to use the bcompiler bytecodes to recreate and modify a class. However it is possible to retrieve data from a bcompiled bytecode file - so don't put your private passwords or anything in it.

Installation

short installation note:

You need at least PHP 4.3. for the compression to work
To install on PHP 4.3 and later at the unix command prompt type pear install bcompiler
To install on Windows, until the binary package distribution mechanism is finished please search the archives of the pear-general mailing list for pre-built packages. (or send an email to it if you could not find a reference)
To install on older versions you need to make some slight changes to the build.
untar the bcompiler.tgz archive into php4/ext.(Get it directly from PECL http://pecl.php.net/get/bcompiler)
If the new directory is now called something like bcompiler-0.x, then you should rename it to bcompiler (except you only want to build it as self-contained php-module).
If you are using versions before PHP 4.3, the you will need to copy the Makefile.in.old to Makefile.in and config.m4.old to config.m4.
run phpize in ext/bcompiler
run ./buildconf in php4
run configure with --enable-bcompiler (and your other options)
make; make install
that's it.

Contact Information

If you have comments, bugfixes, enhancements or want to help developing this beast, you can drop me a mail at alan_k@php.net. Any help is very welcome.

Table of Contents
bcompiler_load_exe -- Reads and creates classes from a bcompiler exe file
bcompiler_load -- Reads and creates classes from a bz compressed file
bcompiler_parse_class -- Reads the bytecodes of a class and calls back to a user function
bcompiler_read -- Reads and creates classes from a filehandle
bcompiler_write_class -- Writes an defined class as bytecodes
bcompiler_write_constant -- Writes a defined constant as bytecodes
bcompiler_write_exe_footer -- Writes the start pos, and sig to the end of a exe type file
bcompiler_write_file -- Writes a php source file as bytecodes
bcompiler_write_footer -- Writes the single character \x00 to indicate End of compiled data
bcompiler_write_function -- Writes an defined function as bytecodes
bcompiler_write_functions_from_file -- Writes all functions defined in a file as bytecodes
bcompiler_write_header -- Writes the bcompiler header


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