Question

Currently I want to read some data (metadata, scene names, mesh count, vertices count …) from a .blend file with the unpack() function of PHP refering to the Blender SDNA documentation:

http://www.atmind.nl/blender/blender-sdna-256.html

Is there some easy solution to read all these information with some existing classes or libraries or do I have to read block by block from the file and write my own functions / clas / library (so I can create something like an object)?

Answer 1

After consultation with php manual I can tell you that php just doesn’t provide way to read binary files, but I think there’s quite nice way to do this (inspirited by c and fread)

class BinaryReader {
    const FLOAT_SIZE = 4;

    protected $fp = null; // file pointer
    ...

    public function readFloat() {
         $data = fread( $fp, self::FLOAT_SIZE);
         $array = unpack( 'f', $data);
         return $array[0];
    }

     // Reading unsigned short int
     public function readUint16( $endian = null){
          if( $endian === null){
               $endian = $this->getDefaultEndian();
          }

          // Assuming _fread handles EOF and similar things
          $data = $this->_fread( 2);
          $array = unapack( ($endian == BIG_ENDIAN ? 'n' : 'v'), $data);
          return $array[0];
     }

    // ... All other binary type functions

    // You may also write it more general:
    public function readByReference( &$variable){
        switch( get_type( $variable)){
            case 'double':
                return $this->readDouble();
            ...
        }
    }
}

If you have any improvements or tips, just post them in the comment I’ll be glad to extend the answer.