#!/usr/bin/env php
<?php
$file = $argv[1];
$hdl = fopen($file, 'rb');

//$magic = fread($hdl, 2);
$indexLen = number32bit(fread($hdl, 4));
debug('Index length: ' . $indexLen);

parseEntry();
fclose($hdl);

function parseEntry($level = 0)
{
    global $hdl;
    $type = number8bit(fread($hdl, 1));
    if ($type === 0) {
        parseFile($level);
    } else if ($type === 1) {
        parseDir($level);
    } else {
        error('Unknown type: ' . $type);
    }
}

function parseDir($level = 0)
{
    global $hdl;
    $nameLen = number8bit(fread($hdl, 1));
    if ($nameLen > 0) {
        $name = fread($hdl, $nameLen);
    } else {
        $name = '';
    }
    $numFiles = number8bit(fread($hdl, 1));
    echo str_repeat('  ', $level)
        . $name . "/"
        . "   (" . $numFiles . " files)\n";

    for ($n = 0; $n < $numFiles; $n++) {
        parseEntry($level + 1);
    }
}

function parseFile($level)
{
    global $hdl;
    $nameLen = number8bit(fread($hdl, 1));
    $name    = fread($hdl, $nameLen);

    $fileSize = number32bit(fread($hdl, 4));
    $offset   = number32bit(fread($hdl, 4));
    $unknown  = number32bit(fread($hdl, 4));
    $compressed = ($fileSize != $unknown);
    echo str_pad(
        str_repeat('  ', $level)
        . $name,
        30, ' '
    )  
        . "  " . str_pad($fileSize, 8, ' ', STR_PAD_LEFT) . " bytes"
        . ", offset " . str_pad($offset, 8, ' ')
        . "  compressed: " . ($compressed ? 'yes' : 'no')
        . "\n";
}

function number8bit($binary)
{
    return unpack('C', $binary)[1];
}

function number32bit($binary)
{
    return unpack('V', $binary)[1];
}

function error($msg)
{
    file_put_contents('php://stderr', $msg . "\n");
}
function debug($msg)
{
    echo $msg . "\n";
}
?>