Compound Files FAST

The compound file format goes by a few different names, including "Object Linking and Embedding (OLE) Compound File (CF)", "Compound Binary File", "Compound Document File", and "OLE2." The underlying concept with this file format is to create what amounts to a filesystem within a file. The compound file binary format is used for .doc, .ppt, and .xls files, among others.

This library was designed to address a lack of a quality options for parsing compound file binary format in PHP. When I needed to parse compound files in PHP I looked around and found one implementation that was both slow made many assumptions that did not conform to the specification. In implementing this library, speed and standard compliance were at the forefront, ensuring the broadest compatibility with different file implementation and that when used at scale processing many files will not kill server performance. The library was also designed to be easily extensible using Object-Oriented best practices throughout.

To use the library, there are two options depending on your specific needs: a stream wrapper or raw access to the parsed file fields. Below, both of these approaches are demonstrated. The stream option provides a nice abstraction if you have functions that accept a PHP resource that you want to pass in a single stream from a compound file.

Stream Wrapper

if ( in_array( 'cfbf', stream_get_wrappers() ) ) {
   stream_wrapper_unregister( 'cfbf' );
}
stream_wrapper_register( 'cfbf', 'CompoundFileStream' );
 
// "WordDocument" is the name of the stream within the CFBF file
$fp = fopen( 'cfbf://' . $filePath . '#WordDocument', 'r' );
$content = stream_get_contents( $fp );

Raw File Access

$fp = fopen( $filePath, 'r' );
$cfb = new CompoundFile( $fp );

// "WordDocument" is the name of the stream within the CFBF file
$content = $cfb->getStream( 'WordDocument' );

TODO

Below are the major future tasks I have in mind. Feel free to contribute :)

• Add WordFile, PowerPointFile, and ExcelFile extensions of the existing CompoundFile class which will provide convenience methods to interact with these common compound file types.
• Add unit tests
• Support writing compound files (right now only reading is supported)