nes-proj/tools/coffee-manager/org/contikios/coffee/CoffeeMicroLog.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.
*
* @author Nicolas Tsiftes
*
*/
package org.contikios.coffee;
import java.io.IOException;
public class CoffeeMicroLog extends CoffeeFile {
private int logRecords;
private int logRecordSize;
private int indexStart;
private int indexSize;
private int recordStart;
private int[] index;
public CoffeeMicroLog(CoffeeFS fs, CoffeeHeader header)
throws IOException {
super(fs, header);
CoffeeConfiguration conf = fs.getConfiguration();
if (header.logRecordSize == 0) {
logRecordSize = conf.pageSize;
}
if (header.logRecords == 0) {
logRecords = conf.defaultLogSize / logRecordSize;
} else {
logRecords = header.logRecords;
}
indexStart = header.getPage() * conf.pageSize +
header.rawLength();
/* An index entry uses two bytes. */
indexSize = logRecords * 2;
recordStart = indexStart + indexSize;
index = new int[logRecords];
byte[] bytes = new byte[2];
for (int i = 0; i < logRecords; i++) {
coffeeFS.getImage().read(bytes, bytes.length,
indexStart + i * 2);
index[i] = bytes[1] << 8 | bytes[0];
}
}
public byte[] getRegion(int region) throws IOException {
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for (int i = logRecords - 1; i >= 0; i--) {
if (index[i] - 1 == region) {
byte[] bytes = new byte[logRecordSize];
coffeeFS.getImage().read(bytes, bytes.length,
recordStart + i * logRecordSize);
return bytes;
}
}
return null;
}
public int getLogRecords() {
return logRecords;
}
public int getLogRecordSize() {
return logRecordSize;
}
}