| /* |
| * Copyright (C) 2003-2009 JNode.org |
| * 2009,2010 Matthias Treydte <mt@waldheinz.de> |
| * |
| * This library is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU Lesser General Public License as published |
| * by the Free Software Foundation; either version 2.1 of the License, or |
| * (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| * License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public License |
| * along with this library; If not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| */ |
| |
| package de.waldheinz.fs.fat; |
| |
| /** |
| * Enumerates the different entry sizes of 12, 16 and 32 bits for the different |
| * FAT flavours. |
| * |
| * @author Ewout Prangsma <epr at jnode.org> |
| * @author Matthias Treydte <waldheinz at gmail.com> |
| */ |
| public enum FatType { |
| |
| /** |
| * Represents a 12-bit file allocation table. |
| */ |
| FAT12((1 << 12) - 16, 0xFFFL, 1.5f, "FAT12 ") { //NOI18N |
| |
| @Override |
| long readEntry(byte[] data, int index) { |
| final int idx = (int) (index * 1.5); |
| final int b1 = data[idx] & 0xFF; |
| final int b2 = data[idx + 1] & 0xFF; |
| final int v = (b2 << 8) | b1; |
| |
| if ((index % 2) == 0) { |
| return v & 0xFFF; |
| } else { |
| return v >> 4; |
| } |
| } |
| |
| @Override |
| void writeEntry(byte[] data, int index, long entry) { |
| final int idx = (int) (index * 1.5); |
| |
| if ((index % 2) == 0) { |
| data[idx] = (byte) (entry & 0xFF); |
| data[idx + 1] = (byte) ((entry >> 8) & 0x0F); |
| } else { |
| data[idx] |= (byte) ((entry & 0x0F) << 4); |
| data[idx + 1] = (byte) ((entry >> 4) & 0xFF); |
| } |
| } |
| }, |
| |
| /** |
| * Represents a 16-bit file allocation table. |
| */ |
| FAT16((1 << 16) - 16, 0xFFFFL, 2.0f, "FAT16 ") { //NOI18N |
| |
| @Override |
| long readEntry(byte[] data, int index) { |
| final int idx = index << 1; |
| final int b1 = data[idx] & 0xFF; |
| final int b2 = data[idx + 1] & 0xFF; |
| return (b2 << 8) | b1; |
| } |
| |
| @Override |
| void writeEntry(byte[] data, int index, long entry) { |
| final int idx = index << 1; |
| data[idx] = (byte) (entry & 0xFF); |
| data[idx + 1] = (byte) ((entry >> 8) & 0xFF); |
| } |
| }, |
| |
| /** |
| * Represents a 32-bit file allocation table. |
| */ |
| FAT32((1 << 28) - 16, 0xFFFFFFFFL, 4.0f, "FAT32 ") { //NOI18N |
| |
| @Override |
| long readEntry(byte[] data, int index) { |
| final int idx = index * 4; |
| final long l1 = data[idx] & 0xFF; |
| final long l2 = data[idx + 1] & 0xFF; |
| final long l3 = data[idx + 2] & 0xFF; |
| final long l4 = data[idx + 3] & 0xFF; |
| return (l4 << 24) | (l3 << 16) | (l2 << 8) | l1; |
| } |
| |
| @Override |
| void writeEntry(byte[] data, int index, long entry) { |
| final int idx = index << 2; |
| data[idx] = (byte) (entry & 0xFF); |
| data[idx + 1] = (byte) ((entry >> 8) & 0xFF); |
| data[idx + 2] = (byte) ((entry >> 16) & 0xFF); |
| data[idx + 3] = (byte) ((entry >> 24) & 0xFF); |
| } |
| }; |
| |
| private final long minReservedEntry; |
| private final long maxReservedEntry; |
| private final long eofCluster; |
| private final long eofMarker; |
| private final long bitMask; |
| private final int maxClusters; |
| private final String label; |
| private final float entrySize; |
| |
| private FatType(int maxClusters, |
| long bitMask, float entrySize, String label) { |
| |
| this.minReservedEntry = (0xFFFFFF0L & bitMask); |
| this.maxReservedEntry = (0xFFFFFF6L & bitMask); |
| this.eofCluster = (0xFFFFFF8L & bitMask); |
| this.eofMarker = (0xFFFFFFFL & bitMask); |
| this.entrySize = entrySize; |
| this.label = label; |
| this.maxClusters = maxClusters; |
| this.bitMask = bitMask; |
| } |
| |
| abstract long readEntry(byte[] data, int index); |
| |
| abstract void writeEntry(byte[] data, int index, long entry); |
| |
| /** |
| * Returns the maximum number of clusters this file system can address. |
| * |
| * @return the maximum cluster count supported |
| */ |
| long maxClusters() { |
| return this.maxClusters; |
| } |
| |
| /** |
| * Returns the human-readable FAT name string as written to the |
| * {@link com.meetwise.fs.BootSector}. |
| * |
| * @return the boot sector label for this FAT type |
| */ |
| String getLabel() { |
| return this.label; |
| } |
| |
| boolean isReservedCluster(long entry) { |
| return ((entry >= minReservedEntry) && (entry <= maxReservedEntry)); |
| } |
| |
| boolean isEofCluster(long entry) { |
| return (entry >= eofCluster); |
| } |
| |
| long getEofMarker() { |
| return eofMarker; |
| } |
| |
| float getEntrySize() { |
| return entrySize; |
| } |
| |
| long getBitMask() { |
| return bitMask; |
| } |
| } |