Imported sourceshms

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/branches/hms@2 f203690c-595d-4dc9-a70b-905162fa7fd2

1 files changed, 98 insertions, 0 deletions

diff --git a/src/java/com/healthmarketscience/jackcess/InlineUsageMap.java b/src/java/com/healthmarketscience/jackcess/InlineUsageMap.java
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+++ b/src/java/com/healthmarketscience/jackcess/InlineUsageMap.java
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+/*
+Copyright (c) 2005 Health Market Science, Inc.
+
+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., 59 Temple Place, Suite 330, Boston, MA  02111-1307
+USA
+
+You can contact Health Market Science at info@healthmarketscience.com
+or at the following address:
+
+Health Market Science
+2700 Horizon Drive
+Suite 200
+King of Prussia, PA 19406
+*/
+
+package com.healthmarketscience.jackcess;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+/**
+ * Usage map whose map is written inline in the same page.  This type of map
+ * can contain a maximum of 512 pages, and is always used for free space maps.
+ * It has a start page, which all page numbers in its map are calculated as
+ * starting from.
+ * @author Tim McCune
+ */
+public class InlineUsageMap extends UsageMap {
+  
+  /** Size in bytes of the map */
+  private static final int MAP_SIZE = 64;
+  
+  /** First page that this usage map applies to */
+  private int _startPage = 0;
+  
+  /**
+   * @param pageChannel Used to read in pages
+   * @param dataBuffer Buffer that contains this map's declaration
+   * @param pageNum Page number that this usage map is contained in
+   * @param format Format of the database that contains this usage map
+   * @param rowStart Offset at which the declaration starts in the buffer
+   */
+  public InlineUsageMap(PageChannel pageChannel, ByteBuffer dataBuffer,
+      int pageNum, JetFormat format, short rowStart)
+  throws IOException
+  {
+    super(pageChannel, dataBuffer, pageNum, format, rowStart);
+    _startPage = dataBuffer.getInt(rowStart + 1);
+    processMap(dataBuffer, 0, _startPage);
+  }
+  
+  //Javadoc copied from UsageMap
+  protected void addOrRemovePageNumber(final int pageNumber, boolean add)
+  throws IOException
+  {
+    if (add && pageNumber < _startPage) {
+      throw new IOException("Can't add page number " + pageNumber +
+          " because it is less than start page " + _startPage);
+    }
+    int relativePageNumber = pageNumber - _startPage;
+    ByteBuffer buffer = getDataBuffer();
+    if ((!add && !getPageNumbers().remove(new Integer(pageNumber))) || (add &&
+        (relativePageNumber > MAP_SIZE * 8 - 1)))
+    {
+      //Increase the start page to the current page and clear out the map.
+      _startPage = pageNumber;
+      buffer.position(getRowStart() + 1);
+      buffer.putInt(_startPage);
+      getPageNumbers().clear();
+      if (!add) {
+        for (int j = 0; j < MAP_SIZE; j++) {
+          buffer.put((byte) 0xff); //Fill bitmap with 1s
+        }
+        for (int j = _startPage; j < _startPage + MAP_SIZE * 8; j++) {
+          getPageNumbers().add(new Integer(j)); //Fill our list with page numbers
+        }
+      }
+      getPageChannel().writePage(buffer, getDataPageNumber());
+      relativePageNumber = pageNumber - _startPage;
+    }
+    updateMap(pageNumber, relativePageNumber, 1 << (relativePageNumber % 8), buffer, add);
+    //Write the updated map back to disk
+    getPageChannel().writePage(buffer, getDataPageNumber());
+  }
+  
+}