73 lines
2.5 KiB
Java
73 lines
2.5 KiB
Java
package com.bytezone.diskbrowser.nib;
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// -----------------------------------------------------------------------------------//
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abstract class DiskReader
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// -----------------------------------------------------------------------------------//
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{
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static final int SECTOR_SIZE = 256;
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static final int BLOCK_SIZE = 512;
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static final byte[] dataPrologue = { (byte) 0xD5, (byte) 0xAA, (byte) 0xAD };
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static DiskReader reader13;
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static DiskReader reader16;
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static DiskReader readerGCR;
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final int sectorsPerTrack;
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// ---------------------------------------------------------------------------------//
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DiskReader (int sectorsPerTrack)
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// ---------------------------------------------------------------------------------//
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{
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this.sectorsPerTrack = sectorsPerTrack;
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}
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// ---------------------------------------------------------------------------------//
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static DiskReader getInstance (int sectors)
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// ---------------------------------------------------------------------------------//
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{
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switch (sectors)
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{
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case 13:
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if (reader13 == null)
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reader13 = new DiskReader13Sector ();
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return reader13;
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case 16:
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if (reader16 == null)
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reader16 = new DiskReader16Sector ();
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return reader16;
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case 0:
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if (readerGCR == null)
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readerGCR = new DiskReaderGCR ();
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return readerGCR;
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default:
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return null;
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}
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}
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// ---------------------------------------------------------------------------------//
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byte[] decodeSector (byte[] buffer) throws DiskNibbleException
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// ---------------------------------------------------------------------------------//
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{
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return decodeSector (buffer, 0);
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}
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// reverse 2 bits - 0 <= bits <= 3
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// ---------------------------------------------------------------------------------//
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static int reverse (int bits)
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// ---------------------------------------------------------------------------------//
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{
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return bits == 1 ? 2 : bits == 2 ? 1 : bits;
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}
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// ---------------------------------------------------------------------------------//
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abstract byte[] decodeSector (byte[] buffer, int offset) throws DiskNibbleException;
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// ---------------------------------------------------------------------------------//
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// ---------------------------------------------------------------------------------//
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abstract byte[] encodeSector (byte[] buffer);
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// ---------------------------------------------------------------------------------//
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}
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