96 lines
3.0 KiB
Java
96 lines
3.0 KiB
Java
/*
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* Copyright (c) 2009, Swedish Institute of Computer Science
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @author Nicolas Tsiftes
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*
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*/
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package org.contikios.coffee;
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import java.io.IOException;
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public class CoffeeMicroLog extends CoffeeFile {
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private int logRecords;
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private int logRecordSize;
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private int indexStart;
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private int indexSize;
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private int recordStart;
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private int[] index;
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public CoffeeMicroLog(CoffeeFS fs, CoffeeHeader header)
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throws IOException {
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super(fs, header);
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CoffeeConfiguration conf = fs.getConfiguration();
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if (header.logRecordSize == 0) {
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logRecordSize = conf.pageSize;
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}
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if (header.logRecords == 0) {
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logRecords = conf.defaultLogSize / logRecordSize;
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} else {
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logRecords = header.logRecords;
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}
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indexStart = header.getPage() * conf.pageSize +
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header.rawLength();
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/* An index entry uses two bytes. */
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indexSize = logRecords * 2;
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recordStart = indexStart + indexSize;
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index = new int[logRecords];
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byte[] bytes = new byte[2];
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for (int i = 0; i < logRecords; i++) {
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coffeeFS.getImage().read(bytes, bytes.length,
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indexStart + i * 2);
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index[i] = bytes[1] << 8 | bytes[0];
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}
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}
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public byte[] getRegion(int region) throws IOException {
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for (int i = logRecords - 1; i >= 0; i--) {
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if (index[i] - 1 == region) {
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byte[] bytes = new byte[logRecordSize];
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coffeeFS.getImage().read(bytes, bytes.length,
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recordStart + i * logRecordSize);
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return bytes;
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}
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}
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return null;
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}
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public int getLogRecords() {
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return logRecords;
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}
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public int getLogRecordSize() {
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return logRecordSize;
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}
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}
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