agents/COB.php

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<?php
require_once(dirname(__FILE__).'/../support/IReader.php');
require_once(dirname(__FILE__).'/../support/StringReader.php');
require_once(dirname(__FILE__).'/COB/AgentBlock.php');
require_once(dirname(__FILE__).'/COB/FileBlock.php');
require_once(dirname(__FILE__).'/COB/AuthorBlock.php');
require_once(dirname(__FILE__).'/COB/UnknownBlock.php');


define('COB_FORMAT_C1','C1');
define('COB_FORMAT_C2','C2');

class COB {


    private $format;
    private $blocks;



    public function COB(IReader $reader=null) {
        if($reader != null) {
            $this->LoadCOB($reader);
        }
    }



    private function LoadCOB(IReader $reader) {
        if($reader->Read(4) == 'cob2') {
            $reader->Seek(0);
            $this->LoadC2COB($reader);
        } else {
            $string = $reader->GetSubString(0);
            $data = @gzuncompress($string);
            if($data===false) {
                $reader->Seek(0);
                $this->LoadC1COB($reader);
            } else {
                $this->LoadC2COB(new StringReader($data));
            }
        }
    }



    public function LoadC2COB(IReader $reader) {
        $this->format = COB_FORMAT_C2;
        if($reader->Read(4) == 'cob2') {
            while($block = $this->ReadBlock($reader)) {
                $this->blocks[] = $block;
            }
        } else {
            throw new Exception('Not a valid C2 COB file!');
        }
    }


    public function LoadC1COB(IReader $reader) {
        $this->format = COB_FORMAT_C1;
        $version = $reader->ReadInt(2);
        if($version > 4) {
            throw new Exception('Invalid cob file.');
        } else {
            $this->blocks[] = COBAgentBlock::CreateFromReaderC1($reader);
        }
    }

    public function AddBlock(COBBlock $block) {
        //TODO: Check that this block works for this COB type?
        $this->blocks[] = $block;
    }



    private function ReadBlock(IReader $reader) {
        if(!($type = $reader->Read(4))) {
            return false;
        }
        $size = $reader->ReadInt(4);
        switch($type) {
        case 'agnt':
            //we read the entire thing so that if there are errors we can still go on with the other blocks.
            return COBAgentBlock::CreateFromReaderC2($reader);
            break;
        case 'auth':
            return COBAuthorBlock::CreateFromReader(new StringReader($reader->Read($size)));
            break;
        case 'file':
            return COBFileBlock::CreateFromReader(new StringReader($reader->Read($size)));
            break;
        default:
            //throw new Exception('Invalid block type: Probably a bug or an invalid COB file: '.$type);
            //simply ignore unknown block types, in case people add their own
            return new COBUnknownBlock($type,$reader->Read($size));
            break;
        }
    }

    

    public function GetBlocks($type=false) {
        $blocks = array();
        foreach($this->blocks as $block) {
            if($type === false || $type == $block->GetType()) {
                $blocks[] = $block;
            }
        }
        return $blocks;
    }


    public function Compile($format = null) {
        if($format == null) {
            $format = $this->GetType();
        }
        if($format != FORMAT_C1) {
            $format = FORMAT_C2
        }
        switch($format) {
        case FORMAT_C1:
            $this->CompileC1();
        case FORMAT_C2:
            $this->CompileC2();
        default:
            throw new Exception('Non-understood COB format - sorry!');
        }
    }

    // TODO: implement this.
    public function CompileC1() {
        throw new Exception('C1 COB Compilation not yet ready.')
    }
    // TODO: Check accuracy
    public function CompileC2() {
        $data = 'cob2'; 
        foreach($this->blocks as $block) {
            $data .= $block->Compile();
        }    
    }
}
?>