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Diffstat (limited to 'src/main/java/de/waldheinz/fs/fat/Fat32BootSector.java')
| -rw-r--r-- | src/main/java/de/waldheinz/fs/fat/Fat32BootSector.java | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/src/main/java/de/waldheinz/fs/fat/Fat32BootSector.java b/src/main/java/de/waldheinz/fs/fat/Fat32BootSector.java new file mode 100644 index 0000000..eded7ee --- /dev/null +++ b/src/main/java/de/waldheinz/fs/fat/Fat32BootSector.java @@ -0,0 +1,209 @@ +/* + * Copyright (C) 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; + +import de.waldheinz.fs.BlockDevice; +import java.io.IOException; + +/** + * Contains the FAT32 specific parts of the boot sector. + * + * @author Matthias Treydte <matthias.treydte at meetwise.com> + */ +final class Fat32BootSector extends BootSector { + + /** + * The offset to the entry specifying the first cluster of the FAT32 + * root directory. + */ + public final static int ROOT_DIR_FIRST_CLUSTER_OFFSET = 0x2c; + + /** + * The offset to the 4 bytes specifying the sectors per FAT value. + */ + public static final int SECTORS_PER_FAT_OFFSET = 0x24; + + /** + * Offset to the file system type label. + */ + public static final int FILE_SYSTEM_TYPE_OFFSET = 0x52; + + public static final int VERSION_OFFSET = 0x2a; + public static final int VERSION = 0; + + public static final int FS_INFO_SECTOR_OFFSET = 0x30; + public static final int BOOT_SECTOR_COPY_OFFSET = 0x32; + public static final int EXTENDED_BOOT_SIGNATURE_OFFSET = 0x42; + + /* + * TODO: make this constructor private + */ + public Fat32BootSector(BlockDevice device) throws IOException { + super(device); + } + + @Override + public void init() throws IOException { + super.init(); + + set16(VERSION_OFFSET, VERSION); + + setBootSectorCopySector(6); /* as suggested by M$ */ + } + + /** + * Returns the first cluster in the FAT that contains the root directory. + * + * @return the root directory's first cluster + */ + public long getRootDirFirstCluster() { + return get32(ROOT_DIR_FIRST_CLUSTER_OFFSET); + } + + /** + * Sets the first cluster of the root directory. + * + * @param value the root directory's first cluster + */ + public void setRootDirFirstCluster(long value) { + if (getRootDirFirstCluster() == value) return; + + set32(ROOT_DIR_FIRST_CLUSTER_OFFSET, value); + } + + /** + * Sets the sectur number that contains a copy of the boot sector. + * + * @param sectNr the sector that contains a boot sector copy + */ + public void setBootSectorCopySector(int sectNr) { + if (getBootSectorCopySector() == sectNr) return; + if (sectNr < 0) throw new IllegalArgumentException( + "boot sector copy sector must be >= 0"); + + set16(BOOT_SECTOR_COPY_OFFSET, sectNr); + } + + /** + * Returns the sector that contains a copy of the boot sector, or 0 if + * there is no copy. + * + * @return the sector number of the boot sector copy + */ + public int getBootSectorCopySector() { + return get16(BOOT_SECTOR_COPY_OFFSET); + } + + /** + * Sets the 11-byte volume label stored at offset 0x47. + * + * @param label the new volume label, may be {@code null} + */ + public void setVolumeLabel(String label) { + for (int i=0; i < 11; i++) { + final byte c = + (label == null) ? 0 : + (label.length() > i) ? (byte) label.charAt(i) : 0x20; + + set8(0x47 + i, c); + } + } + + public int getFsInfoSectorNr() { + return get16(FS_INFO_SECTOR_OFFSET); + } + + public void setFsInfoSectorNr(int offset) { + if (getFsInfoSectorNr() == offset) return; + + set16(FS_INFO_SECTOR_OFFSET, offset); + } + + @Override + public void setSectorsPerFat(long v) { + if (getSectorsPerFat() == v) return; + + set32(SECTORS_PER_FAT_OFFSET, v); + } + + @Override + public long getSectorsPerFat() { + return get32(SECTORS_PER_FAT_OFFSET); + } + + @Override + public FatType getFatType() { + return FatType.FAT32; + } + + @Override + public void setSectorCount(long count) { + super.setNrTotalSectors(count); + } + + @Override + public long getSectorCount() { + return super.getNrTotalSectors(); + } + + /** + * This is always 0 for FAT32. + * + * @return always 0 + */ + @Override + public int getRootDirEntryCount() { + return 0; + } + + public void setFileSystemId(int id) { + super.set32(0x43, id); + } + + public int getFileSystemId() { + return (int) super.get32(0x43); + } + + /** + * Writes a copy of this boot sector to the specified device, if a copy + * is requested. + * + * @param device the device to write the boot sector copy to + * @throws IOException on write error + * @see #getBootSectorCopySector() + */ + public void writeCopy(BlockDevice device) throws IOException { + if (getBootSectorCopySector() > 0) { + final long offset = getBootSectorCopySector() * SIZE; + buffer.rewind(); + buffer.limit(buffer.capacity()); + device.write(offset, buffer); + } + } + + @Override + public int getFileSystemTypeLabelOffset() { + return FILE_SYSTEM_TYPE_OFFSET; + } + + @Override + public int getExtendedBootSignatureOffset() { + return EXTENDED_BOOT_SIGNATURE_OFFSET; + } +} |