mirror of
https://github.com/dmolony/DiskBrowser.git
synced 2024-06-01 03:41:29 +00:00
225 lines
7.0 KiB
Java
225 lines
7.0 KiB
Java
package com.bytezone.diskbrowser.prodos.write;
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import static com.bytezone.diskbrowser.prodos.ProdosConstants.BLOCK_SIZE;
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import static com.bytezone.diskbrowser.prodos.ProdosConstants.SAPLING;
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import static com.bytezone.diskbrowser.prodos.ProdosConstants.SEEDLING;
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import static com.bytezone.diskbrowser.prodos.ProdosConstants.TREE;
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// -----------------------------------------------------------------------------------//
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public class FileWriter
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// -----------------------------------------------------------------------------------//
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{
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private final ProdosDisk disk;
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private IndexBlock indexBlock = null;
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private MasterIndexBlock masterIndexBlock = null;
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byte storageType;
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int keyPointer;
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int blocksUsed;
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int eof;
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// ---------------------------------------------------------------------------------//
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FileWriter (ProdosDisk disk)
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// ---------------------------------------------------------------------------------//
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{
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this.disk = disk;
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}
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// ---------------------------------------------------------------------------------//
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void writeFile (byte[] dataBuffer, int eof) throws DiskFullException
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// ---------------------------------------------------------------------------------//
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{
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this.eof = eof;
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int dataPtr = 0;
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int remaining = eof;
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while (dataPtr < eof)
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{
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int actualBlockNo = allocateNextBlock ();
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map (dataPtr / BLOCK_SIZE, actualBlockNo);
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int bufferPtr = actualBlockNo * BLOCK_SIZE;
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int tfr = Math.min (remaining, BLOCK_SIZE);
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System.arraycopy (dataBuffer, dataPtr, disk.getBuffer (), bufferPtr, tfr);
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dataPtr += BLOCK_SIZE;
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remaining -= BLOCK_SIZE;
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}
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writeIndices ();
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}
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// ---------------------------------------------------------------------------------//
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void writeRecord (int recordNo, byte[] dataBuffer, int recordLength)
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throws DiskFullException
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// ---------------------------------------------------------------------------------//
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{
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assert recordLength > 0;
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int destPtr = recordLength * recordNo;
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int remaining = Math.min (recordLength, dataBuffer.length);
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int max = destPtr + remaining;
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int dataPtr = 0;
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if (eof < max)
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eof = max;
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while (destPtr < max)
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{
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int logicalBlockNo = destPtr / BLOCK_SIZE;
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int blockOffset = destPtr % BLOCK_SIZE;
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int tfr = Math.min (BLOCK_SIZE - blockOffset, remaining);
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int actualBlockNo = getActualBlockNo (logicalBlockNo);
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int bufferPtr = actualBlockNo * BLOCK_SIZE + blockOffset;
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System.arraycopy (dataBuffer, dataPtr, disk.getBuffer (), bufferPtr, tfr);
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destPtr += tfr;
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dataPtr += tfr;
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remaining -= tfr;
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}
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writeIndices ();
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}
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// ---------------------------------------------------------------------------------//
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private int allocateNextBlock () throws DiskFullException
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// ---------------------------------------------------------------------------------//
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{
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blocksUsed++;
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return disk.allocateNextBlock ();
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}
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// ---------------------------------------------------------------------------------//
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private int getActualBlockNo (int logicalBlockNo) throws DiskFullException
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// ---------------------------------------------------------------------------------//
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{
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int actualBlockNo = 0;
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switch (storageType)
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{
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case TREE:
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actualBlockNo =
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masterIndexBlock.get (logicalBlockNo / 256).get (logicalBlockNo % 256);
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break;
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case SAPLING:
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if (logicalBlockNo < 256)
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actualBlockNo = indexBlock.get (logicalBlockNo);
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break;
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case SEEDLING:
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if (logicalBlockNo == 0)
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actualBlockNo = keyPointer;
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break;
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}
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if (actualBlockNo == 0)
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{
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actualBlockNo = allocateNextBlock ();
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map (logicalBlockNo, actualBlockNo);
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}
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return actualBlockNo;
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}
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// ---------------------------------------------------------------------------------//
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private void writeIndices ()
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// ---------------------------------------------------------------------------------//
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{
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if (storageType == TREE)
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masterIndexBlock.write (disk.getBuffer ());
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else if (storageType == SAPLING)
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indexBlock.write (disk.getBuffer ());
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}
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// ---------------------------------------------------------------------------------//
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private void map (int logicalBlockNo, int actualBlockNo) throws DiskFullException
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// ---------------------------------------------------------------------------------//
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{
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if (logicalBlockNo > 255) // potential TREE
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{
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if (storageType != TREE)
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{
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masterIndexBlock = new MasterIndexBlock (allocateNextBlock ());
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if (storageType == SAPLING) // sapling -> tree
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{
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masterIndexBlock.set (0, indexBlock);
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}
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else if (storageType == SEEDLING) // seedling -> sapling -> tree
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{
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indexBlock = new IndexBlock (allocateNextBlock ());
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indexBlock.setPosition (0, keyPointer);
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masterIndexBlock.set (0, indexBlock);
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}
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keyPointer = masterIndexBlock.blockNo;
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storageType = TREE;
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indexBlock = null;
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}
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getIndexBlock (logicalBlockNo / 0x100).setPosition (logicalBlockNo % 0x100,
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actualBlockNo);
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}
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else if (logicalBlockNo > 0) // potential SAPLING
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{
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if (storageType == TREE) // already a tree
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{
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getIndexBlock (0).setPosition (logicalBlockNo, actualBlockNo);
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}
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else if (storageType == SAPLING) // already a sapling
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{
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indexBlock.setPosition (logicalBlockNo, actualBlockNo);
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}
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else // new file or already a seedling
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{
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indexBlock = new IndexBlock (allocateNextBlock ());
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if (storageType == SEEDLING) // seedling -> sapling
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indexBlock.setPosition (0, keyPointer);
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keyPointer = indexBlock.blockNo;
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storageType = SAPLING;
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indexBlock.setPosition (logicalBlockNo, actualBlockNo);
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}
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}
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else if (logicalBlockNo == 0) // potential SEEDLING
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{
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if (storageType == TREE) // already a tree
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{
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getIndexBlock (0).setPosition (0, actualBlockNo);
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}
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else if (storageType == SAPLING) // already a sapling
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{
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indexBlock.setPosition (0, actualBlockNo);
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}
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else
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{
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keyPointer = actualBlockNo;
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storageType = SEEDLING;
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}
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}
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else
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System.out.println ("Error");
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}
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// ---------------------------------------------------------------------------------//
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private IndexBlock getIndexBlock (int position) throws DiskFullException
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// ---------------------------------------------------------------------------------//
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{
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IndexBlock indexBlock = masterIndexBlock.get (position);
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if (indexBlock == null)
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{
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indexBlock = new IndexBlock (allocateNextBlock ());
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masterIndexBlock.set (position, indexBlock);
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}
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return indexBlock;
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}
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}
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