nes-proj/tools/coffee-manager/se/sics/coffee/CoffeeHeader.java

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/*
* Copyright (c) 2009, Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
* $Id: CoffeeHeader.java,v 1.2 2009/08/10 12:51:52 nvt-se Exp $
*
* @author Nicolas Tsiftes
*
*/
package se.sics.coffee;
class CoffeeHeader {
private CoffeeFS coffeeFS;
private CoffeeConfiguration conf;
private int page;
private static final int HDR_FLAG_VALID = 0x1;
private static final int HDR_FLAG_ALLOCATED = 0x2;
private static final int HDR_FLAG_OBSOLETE = 0x4;
private static final int HDR_FLAG_MODIFIED = 0x8;
private static final int HDR_FLAG_LOG = 0x10;
private static final int HDR_FLAG_ISOLATED = 0x20;
int logPage;
int logRecords;
int logRecordSize;
int maxPages;
String name;
private boolean valid;
private boolean allocated;
private boolean obsolete;
private boolean modified;
private boolean log;
private boolean isolated;
public CoffeeHeader(CoffeeFS coffeeFS, int page) {
this.coffeeFS = coffeeFS;
this.page = page;
conf = coffeeFS.getConfiguration();
}
public CoffeeHeader(CoffeeFS coffeeFS, int page, byte[] bytes) {
this.coffeeFS = coffeeFS;
this.page = page;
processRawHeader(bytes);
}
private void processRawHeader(byte[] bytes) {
int index = 0;
logPage = getPageValue(bytes, 0);
index += conf.pageTypeSize;
logRecords = bytes[index] + (bytes[index + 1] << 8);
index += 2;
logRecordSize = bytes[index] + (bytes[index + 1] << 8);
index += 2;
maxPages = getPageValue(bytes, index);
index += conf.pageTypeSize;
index++; // Skip deprecated EOF hint field.
processFlags((int)bytes[index]);
index++;
name = new String(bytes).substring(index,
index + conf.NAME_LENGTH);
int nullCharOffset = name.indexOf(0);
if (nullCharOffset >= 0) {
name = name.substring(0, nullCharOffset);
}
}
private byte composeFlags() {
byte flags = 0;
if (valid) {
flags |= HDR_FLAG_VALID;
}
if (allocated) {
flags |= HDR_FLAG_ALLOCATED;
}
if (obsolete) {
flags |= HDR_FLAG_OBSOLETE;
}
if (modified) {
flags |= HDR_FLAG_MODIFIED;
}
if (log) {
flags |= HDR_FLAG_LOG;
}
if (isolated) {
flags |= HDR_FLAG_ISOLATED;
}
return flags;
}
private void processFlags(int flags) {
if ((flags & HDR_FLAG_VALID) != 0) {
valid = true;
}
if ((flags & HDR_FLAG_ALLOCATED) != 0) {
allocated = true;
}
if ((flags & HDR_FLAG_OBSOLETE) != 0) {
obsolete = true;
}
if ((flags & HDR_FLAG_MODIFIED) != 0) {
modified = true;
}
if ((flags & HDR_FLAG_LOG) != 0) {
log = true;
}
if ((flags & HDR_FLAG_ISOLATED) != 0) {
isolated = true;
}
}
private byte[] setPageValue(int page) {
byte[] bytes = new byte[conf.pageTypeSize];
for (int i = conf.pageTypeSize - 1; i >= 0; i--) {
bytes[i] = (byte) (page >> (8 * i));
}
return bytes;
}
private int getPageValue(byte[] bytes, int offset) {
int page = 0;
for (int i = 0; i < conf.pageTypeSize; i++) {
page |= bytes[offset + i] << (8 * i);
}
return page;
}
public byte[] toRawHeader() {
byte[] bytes = new byte[2 * conf.pageTypeSize +
conf.NAME_LENGTH + 6];
int index = 0;
System.arraycopy(setPageValue(logPage), 0, bytes, 0,
conf.pageTypeSize);
index += conf.pageTypeSize;
bytes[index++] = (byte) (logRecords >> 8);
bytes[index++] = (byte) logRecords;
bytes[index++] = (byte) (logRecordSize >> 8);
bytes[index++] = (byte) logRecordSize;
System.arraycopy(setPageValue(maxPages), 0, bytes, index,
conf.pageTypeSize);
index += conf.pageTypeSize;
bytes[index++] = 0; // Deprecated EOF hint field.
bytes[index++] = composeFlags();
byte[] nameBytes = name.getBytes();
int copyLength = nameBytes.length > conf.NAME_LENGTH ?
conf.NAME_LENGTH : nameBytes.length;
System.arraycopy(nameBytes, 0, bytes, index, copyLength);
return bytes;
}
public int rawLength() {
return 2 * conf.pageTypeSize + conf.NAME_LENGTH + 6;
}
public int getPage() {
return page;
}
public boolean isValid() {
return valid;
}
public boolean isAllocated() {
return allocated;
}
public boolean isObsolete() {
return obsolete;
}
public boolean isModified() {
return modified;
}
public boolean isIsolated() {
return isolated;
}
public boolean isLog() {
return log;
}
public boolean isFree() {
return !isAllocated();
}
public boolean isActive() {
return isAllocated() && !isObsolete() && !isIsolated();
}
public void allocate() {
allocated = true;
}
public void makeObsolete() {
obsolete = true;
}
public void setName(String name) {
this.name = name;
}
public void setReservedSize(int pages) {
maxPages = pages;
}
public int getReservedSize() {
return maxPages;
}
}