apple2_castle_wolfenstein_m.../inspector.html

<html>
    <head>
        <script>
"use strict";

var gFile,
    gData,
    gCAT_TRK_SEC,
    gCAT_TRK,
    gCAT_SEC,
    gContext,
    MAX_SIZE = 143360;

const
    FILE_TYPE_TEXT      = 0x00,
    FILE_TYPE_INTEGER   = 0x01,
    FILE_TYPE_APPLESOFT = 0x02,
    FILE_TYPE_BINARY    = 0x04,
    FILE_TYPE_S         = 0x08,
    FILE_TYPE_RELOC     = 0x10,
    FILE_TYPE_C         = 0x20,
    FILE_TYPE_D         = 0x40,
    FILE_TYPES = [ 'T', 'I', 'A', 'B', 'S', 'R', 'C', 'D' ];

console.log( "Loading..." );

// --- Utility ---

    // Optional: width
    // Optional: character to pad left with, such as '0'; will default to space
    function padLeft( text, width, c )
    {
        if( !width ) return "";
        if( !c ) c = ' ';
        return ("" + new Array( width ).join( c ) + text).slice( -width );
    }

    function makeUnsigned( n )
    {
        return ((n + 256) & 0xFF)|0;
    }

    // @param FILE_TYPE_*
    function makeFileType( fileType )
    {
        var type = 0, raw = fileType;

        while (raw > 0)
        {
            type++;
            raw >>= 1;
        }

        return FILE_TYPES[ type ];
    }

    function parseName( catalogEntry )
    {
        var name = '', c, MAX_FILENAME = 30;

        for( var i = 0; i < MAX_FILENAME; i++ )
        {
            //   0x00: FTOC Track
            //   0x01: FTOC Sector
            //   0x02: Type
            //   0x03: Filename
            c = makeUnsigned( catalogEntry[ 0x3 + i ] ) & 0x7F;
            name += String.fromCharCode( c );
        }

        name = name.trim();
        return name;
    }

    function parseInt16( low, high )
    {
        var n  = makeUnsigned( low )
            n += makeUnsigned( high ) * 256;
        return n;
    }

    function readTrackSectorBytes( track, sector, offset, length )
    {
        if (track  > 34) alert( "Track > 34" );
        if (sector > 16) alert( "Sector > 16" );
        if (offset >256) alert( "Offset > 256" );

        if( gData )
        {
            var begin  = track*16*256 + 256*sector + offset,
                end    = begin + length,
                buffer = gData.slice( begin, end );
            return new Int8Array( buffer );
        }
        return null;
    }

    function readCatalogEntry( i )
    {
        var MAX_ENTRY_LENGTH = 0x23,
            MAX_ENTRIES_PER_SECTOR = 7;

        // Catalog $11,C .. $11,1
        if( !gCAT_TRK || !gCAT_SEC )
            return null;

        // Search directory entries
        var div6 = (i / MAX_ENTRIES_PER_SECTOR)|0,
            mod6 = (i % MAX_ENTRIES_PER_SECTOR)  ,
            offset = MAX_ENTRY_LENGTH*mod6 + 0xB,
            sector = gCAT_SEC - div6;

        if (sector < 1)
            return null;

        //   0x00: FTOC Track
        //   0x01: FTOC Sector
        //   0x02: Type
        //   0x03: Filename
        //   0x21: Length Low
        //   0x22: Length Hi
        var raw = gCAT_TRK_SEC = readTrackSectorBytes( gCAT_TRK, sector, offset, 35 ),
            entry = {},
            type = makeUnsigned( raw[0x02] );

            entry.track  = parseInt    ( raw[0x00] );
            entry.sector = parseInt    ( raw[0x01] );
            entry.locked = (type >= 128)|0;
            entry.type   = makeFileType( type & 0x7F );
            entry.name   = parseName   ( raw );
            entry.length = parseInt16  ( raw[0x21], raw[0x22] );
        return entry;
    }

// --- Implementation ---

/*
    Version 1

        ---------------------------------------
        *A 00006 ^HELLO
        *I 00002 APPLESOFT
        *B 00034 PIX
        *B 00034 PICEX
        *B 00065 SEKTOR
        *B 00047 ^VOCAB
        *B 00006 ^CHARSET
         B 00064 CASTLE
         B 00064 BACKUP
        *T 00007 ^TEXT
        *B 00020 @INIT
        *B 00024 @WOLF
        *B 00024 ^THINGS
        ---------------------------------------
        Total Files: 13, Sectors Used: 397
*/

function catalog()
{
    var entry, i = 0, LOCKED = [ ' ', '*' ], entries = [], text = (new Array( 40 ).join('-')) + '\n', totalSize = 0;

    do
    {
        entry = readCatalogEntry( i++ );
        if( entry && entry.track )
        {
            text += LOCKED[ entry.locked ] + entry.type + ' ' + padLeft( entry.length, 5, '0' ) + ' ' + entry.name + '\n';
            totalSize += entry.length;
            entries.push( entry );
        }
    } while( entry !== null )

    text += (new Array( 40 ).join('-')) + '\n';
    text += 'Total Files: ' + entries.length + ', Sectors Used: ' + totalSize;
console.log( text );
    return entries;
}

function readFile( name )
{
}

function main()
{
    console.log( " Done" );

    if (window.File && window.FileList && window.FileReader)
    {
        document.getElementById('id_select_dsk').addEventListener('change', onSelectFile, false);
    }

    var canvas  = document.getElementById( "canvas" );
    gContext = canvas.getContext( "2d" );

//    gContext.drawImage( image, x, y );
}

// ProgressEvent
// .target = FileReader
// .target.result;
function onLoadFile( e )
{
    if (e.loaded == MAX_SIZE) // .dsk is < 144K
    {
        gFile = e.target;
        gData = e.target.result;

        // Read VTOC to find CATALOG
        gCAT_TRK_SEC = readTrackSectorBytes( 0x11, 0x00, 1, 2 );

        gCAT_TRK = gCAT_TRK_SEC[0]; // $11
        gCAT_SEC = gCAT_TRK_SEC[1]; // $0C

        catalog();
    }
}

function onSelectFile( e )
{
    var iFile, tFile, aFile = e.target.files, nFile = aFile.length, reader;

    e.stopPropagation();
    e.preventDefault();

    for( iFile = 0; iFile < nFile; iFile++ )
    {
        tFile = aFile[ iFile ];

        if( tFile.size > MAX_SIZE )
        {
            alert( ".dsk images must be <= " + MAX_SIZE );
            break;
        }
        reader = new FileReader();
        reader.onload = onLoadFile;
        reader.readAsArrayBuffer( tFile );
    }
}
        </script>
    </head>
<body onload='main();'>

<input type="file" id='id_select_dsk' style='width:100%'>
<br>
<canvas id='canvas' width='560px' height='460px'>
</body>
</html>