/*

 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;

 import java.nio.channels.FileChannel;

 import java.nio.charset.Charset;

 /**

  * Encapsulates constants describing a specific version of the Access Jet format

  * @author Tim McCune

  */

 public abstract class JetFormat {

   /** Maximum size of a record minus OLE objects and Memo fields */

   public static final int MAX_RECORD_SIZE = 1900;  //2kb minus some overhead

   /** the "unit" size for text fields */

   public static final short TEXT_FIELD_UNIT_SIZE = 2;

   /** Maximum size of a text field */

   public static final short TEXT_FIELD_MAX_LENGTH = 255 * TEXT_FIELD_UNIT_SIZE;

   /** Offset in the file that holds the byte describing the Jet format version */

   private static final long OFFSET_VERSION = 20L;

   /** Version code for Jet version 3 */

   private static final byte CODE_VERSION_3 = 0x0;

   /** Version code for Jet version 4 */

   private static final byte CODE_VERSION_4 = 0x1;

   //These constants are populated by this class's constructor.  They can't be

   //populated by the subclass's constructor because they are final, and Java

   //doesn't allow this; hence all the abstract defineXXX() methods.

   /** the name of this format */

   private final String _name;

   /** Database page size in bytes */

   public final int PAGE_SIZE;

   public final long MAX_DATABASE_SIZE;

   public final int MAX_ROW_SIZE;

   public final int PAGE_INITIAL_FREE_SPACE;

   public final int OFFSET_NEXT_TABLE_DEF_PAGE;

   public final int OFFSET_NUM_ROWS;

   public final int OFFSET_NEXT_AUTO_NUMBER;

   public final int OFFSET_TABLE_TYPE;

   public final int OFFSET_MAX_COLS;

   public final int OFFSET_NUM_VAR_COLS;

   public final int OFFSET_NUM_COLS;

   public final int OFFSET_NUM_INDEX_SLOTS;

   public final int OFFSET_NUM_INDEXES;

   public final int OFFSET_OWNED_PAGES;

   public final int OFFSET_FREE_SPACE_PAGES;

   public final int OFFSET_INDEX_DEF_BLOCK;

   public final int OFFSET_INDEX_NUMBER_BLOCK;

   public final int OFFSET_COLUMN_TYPE;

   public final int OFFSET_COLUMN_NUMBER;

   public final int OFFSET_COLUMN_PRECISION;

   public final int OFFSET_COLUMN_SCALE;

   public final int OFFSET_COLUMN_FLAGS;

   public final int OFFSET_COLUMN_COMPRESSED_UNICODE;

   public final int OFFSET_COLUMN_LENGTH;

   public final int OFFSET_COLUMN_VARIABLE_TABLE_INDEX;

   public final int OFFSET_COLUMN_FIXED_DATA_OFFSET;

   public final int OFFSET_TABLE_DEF_LOCATION;

   public final int OFFSET_ROW_START;

   public final int OFFSET_USAGE_MAP_START;

   public final int OFFSET_USAGE_MAP_PAGE_DATA;

   public final int OFFSET_REFERENCE_MAP_PAGE_NUMBERS;

   public final int OFFSET_FREE_SPACE;

   public final int OFFSET_NUM_ROWS_ON_DATA_PAGE;

   public final int MAX_NUM_ROWS_ON_DATA_PAGE;

   public final int OFFSET_INDEX_COMPRESSED_BYTE_COUNT;

   public final int OFFSET_INDEX_ENTRY_MASK;

   public final int OFFSET_PREV_INDEX_PAGE;

   public final int OFFSET_NEXT_INDEX_PAGE;

   public final int OFFSET_CHILD_TAIL_INDEX_PAGE;

   public final int SIZE_INDEX_DEFINITION;

   public final int SIZE_COLUMN_HEADER;

   public final int SIZE_ROW_LOCATION;

   public final int SIZE_LONG_VALUE_DEF;

   public final int MAX_INLINE_LONG_VALUE_SIZE;

   public final int MAX_LONG_VALUE_ROW_SIZE;

   public final int SIZE_TDEF_HEADER;

   public final int SIZE_TDEF_TRAILER;

   public final int SIZE_COLUMN_DEF_BLOCK;

   public final int SIZE_INDEX_ENTRY_MASK;

   public final int USAGE_MAP_TABLE_BYTE_LENGTH;

   public final int MAX_COLUMNS_PER_TABLE;

   public final int MAX_TABLE_NAME_LENGTH;

   public final int MAX_COLUMN_NAME_LENGTH;

   public final int MAX_INDEX_NAME_LENGTH;

   public final Charset CHARSET;

   public static final JetFormat VERSION_4 = new Jet4Format();

   /**

    * @return The Jet Format represented in the passed-in file

    */

   public static JetFormat getFormat(FileChannel channel) throws IOException {

     ByteBuffer buffer = ByteBuffer.allocate(1);

     int bytesRead = channel.read(buffer, OFFSET_VERSION);

     if(bytesRead < 1) {

       throw new IOException("Empty database file");

     }

     buffer.flip();

     byte version = buffer.get();

     if (version == CODE_VERSION_4) {

       return VERSION_4;

     }

     throw new IOException("Unsupported version: " + version);

   }

   private JetFormat(String name) {

     _name = name;

     PAGE_SIZE = definePageSize();

     MAX_DATABASE_SIZE = defineMaxDatabaseSize();

     MAX_ROW_SIZE = defineMaxRowSize();

     PAGE_INITIAL_FREE_SPACE = definePageInitialFreeSpace();

     OFFSET_NEXT_TABLE_DEF_PAGE = defineOffsetNextTableDefPage();

     OFFSET_NUM_ROWS = defineOffsetNumRows();

     OFFSET_NEXT_AUTO_NUMBER = defineOffsetNextAutoNumber();

     OFFSET_TABLE_TYPE = defineOffsetTableType();

     OFFSET_MAX_COLS = defineOffsetMaxCols();

     OFFSET_NUM_VAR_COLS = defineOffsetNumVarCols();

     OFFSET_NUM_COLS = defineOffsetNumCols();

     OFFSET_NUM_INDEX_SLOTS = defineOffsetNumIndexSlots();

     OFFSET_NUM_INDEXES = defineOffsetNumIndexes();

     OFFSET_OWNED_PAGES = defineOffsetOwnedPages();

     OFFSET_FREE_SPACE_PAGES = defineOffsetFreeSpacePages();

     OFFSET_INDEX_DEF_BLOCK = defineOffsetIndexDefBlock();

     OFFSET_INDEX_NUMBER_BLOCK = defineOffsetIndexNumberBlock();

     OFFSET_COLUMN_TYPE = defineOffsetColumnType();

     OFFSET_COLUMN_NUMBER = defineOffsetColumnNumber();

     OFFSET_COLUMN_PRECISION = defineOffsetColumnPrecision();

     OFFSET_COLUMN_SCALE = defineOffsetColumnScale();

     OFFSET_COLUMN_FLAGS = defineOffsetColumnFlags();

     OFFSET_COLUMN_COMPRESSED_UNICODE = defineOffsetColumnCompressedUnicode();

     OFFSET_COLUMN_LENGTH = defineOffsetColumnLength();

     OFFSET_COLUMN_VARIABLE_TABLE_INDEX = defineOffsetColumnVariableTableIndex();

     OFFSET_COLUMN_FIXED_DATA_OFFSET = defineOffsetColumnFixedDataOffset();

     OFFSET_TABLE_DEF_LOCATION = defineOffsetTableDefLocation();

     OFFSET_ROW_START = defineOffsetRowStart();

     OFFSET_USAGE_MAP_START = defineOffsetUsageMapStart();

     OFFSET_USAGE_MAP_PAGE_DATA = defineOffsetUsageMapPageData();

     OFFSET_REFERENCE_MAP_PAGE_NUMBERS = defineOffsetReferenceMapPageNumbers();

     OFFSET_FREE_SPACE = defineOffsetFreeSpace();

     OFFSET_NUM_ROWS_ON_DATA_PAGE = defineOffsetNumRowsOnDataPage();

     MAX_NUM_ROWS_ON_DATA_PAGE = defineMaxNumRowsOnDataPage();

     OFFSET_INDEX_COMPRESSED_BYTE_COUNT = defineOffsetIndexCompressedByteCount();

     OFFSET_INDEX_ENTRY_MASK = defineOffsetIndexEntryMask();

     OFFSET_PREV_INDEX_PAGE = defineOffsetPrevIndexPage();

     OFFSET_NEXT_INDEX_PAGE = defineOffsetNextIndexPage();

     OFFSET_CHILD_TAIL_INDEX_PAGE = defineOffsetChildTailIndexPage();

     SIZE_INDEX_DEFINITION = defineSizeIndexDefinition();

     SIZE_COLUMN_HEADER = defineSizeColumnHeader();

     SIZE_ROW_LOCATION = defineSizeRowLocation();

     SIZE_LONG_VALUE_DEF = defineSizeLongValueDef();

     MAX_INLINE_LONG_VALUE_SIZE = defineMaxInlineLongValueSize();

     MAX_LONG_VALUE_ROW_SIZE = defineMaxLongValueRowSize();

     SIZE_TDEF_HEADER = defineSizeTdefHeader();

     SIZE_TDEF_TRAILER = defineSizeTdefTrailer();

     SIZE_COLUMN_DEF_BLOCK = defineSizeColumnDefBlock();

     SIZE_INDEX_ENTRY_MASK = defineSizeIndexEntryMask();

     USAGE_MAP_TABLE_BYTE_LENGTH = defineUsageMapTableByteLength();

     MAX_COLUMNS_PER_TABLE = defineMaxColumnsPerTable();

     MAX_TABLE_NAME_LENGTH = defineMaxTableNameLength();

     MAX_COLUMN_NAME_LENGTH = defineMaxColumnNameLength();

     MAX_INDEX_NAME_LENGTH = defineMaxIndexNameLength();

     CHARSET = defineCharset();

   }

   protected abstract int definePageSize();

   protected abstract long defineMaxDatabaseSize();

   protected abstract int defineMaxRowSize();

   protected abstract int definePageInitialFreeSpace();

   protected abstract int defineOffsetNextTableDefPage();

   protected abstract int defineOffsetNumRows();

   protected abstract int defineOffsetNextAutoNumber();

   protected abstract int defineOffsetTableType();

   protected abstract int defineOffsetMaxCols();

   protected abstract int defineOffsetNumVarCols();

   protected abstract int defineOffsetNumCols();

   protected abstract int defineOffsetNumIndexSlots();

   protected abstract int defineOffsetNumIndexes();

   protected abstract int defineOffsetOwnedPages();

   protected abstract int defineOffsetFreeSpacePages();

   protected abstract int defineOffsetIndexDefBlock();

   protected abstract int defineOffsetIndexNumberBlock();

   protected abstract int defineOffsetColumnType();

   protected abstract int defineOffsetColumnNumber();

   protected abstract int defineOffsetColumnPrecision();

   protected abstract int defineOffsetColumnScale();

   protected abstract int defineOffsetColumnFlags();

   protected abstract int defineOffsetColumnCompressedUnicode();

   protected abstract int defineOffsetColumnLength();

   protected abstract int defineOffsetColumnVariableTableIndex();

   protected abstract int defineOffsetColumnFixedDataOffset();

   protected abstract int defineOffsetTableDefLocation();

   protected abstract int defineOffsetRowStart();

   protected abstract int defineOffsetUsageMapStart();

   protected abstract int defineOffsetUsageMapPageData();

   protected abstract int defineOffsetReferenceMapPageNumbers();

   protected abstract int defineOffsetFreeSpace();

   protected abstract int defineOffsetNumRowsOnDataPage();

   protected abstract int defineMaxNumRowsOnDataPage();

   protected abstract int defineOffsetIndexCompressedByteCount();

   protected abstract int defineOffsetIndexEntryMask();

   protected abstract int defineOffsetPrevIndexPage();

   protected abstract int defineOffsetNextIndexPage();

   protected abstract int defineOffsetChildTailIndexPage();

   protected abstract int defineSizeIndexDefinition();

   protected abstract int defineSizeColumnHeader();

   protected abstract int defineSizeRowLocation();

   protected abstract int defineSizeLongValueDef();

   protected abstract int defineMaxInlineLongValueSize();

   protected abstract int defineMaxLongValueRowSize();

   protected abstract int defineSizeTdefHeader();

   protected abstract int defineSizeTdefTrailer();

   protected abstract int defineSizeColumnDefBlock();

   protected abstract int defineSizeIndexEntryMask();

   protected abstract int defineUsageMapTableByteLength();

   protected abstract int defineMaxColumnsPerTable();

   protected abstract int defineMaxTableNameLength();

   protected abstract int defineMaxColumnNameLength();

   protected abstract int defineMaxIndexNameLength();

   protected abstract Charset defineCharset();

   @Override

   public String toString() {

     return _name;

   }

   private static final class Jet4Format extends JetFormat {

     private Jet4Format() {

       super("VERSION_4");

     }

     @Override

     protected int definePageSize() { return 4096; }

     @Override

     protected long defineMaxDatabaseSize() {

       return (2L * 1024L * 1024L * 1024L);

     }

     @Override

     protected int defineMaxRowSize() { return 4060; }

     @Override

     protected int definePageInitialFreeSpace() { return PAGE_SIZE - 14; }

     @Override

     protected int defineOffsetNextTableDefPage() { return 4; }

     @Override

     protected int defineOffsetNumRows() { return 16; }

     @Override

     protected int defineOffsetNextAutoNumber() { return 20; }

     @Override

     protected int defineOffsetTableType() { return 40; }

     @Override

     protected int defineOffsetMaxCols() { return 41; }

     @Override

     protected int defineOffsetNumVarCols() { return 43; }

     @Override

     protected int defineOffsetNumCols() { return 45; }

     @Override

     protected int defineOffsetNumIndexSlots() { return 47; }

     @Override

     protected int defineOffsetNumIndexes() { return 51; }

     @Override

     protected int defineOffsetOwnedPages() { return 55; }

     @Override

     protected int defineOffsetFreeSpacePages() { return 59; }

     @Override

     protected int defineOffsetIndexDefBlock() { return 63; }

     @Override

     protected int defineOffsetIndexNumberBlock() { return 52; }

     @Override

     protected int defineOffsetColumnType() { return 0; }

     @Override

     protected int defineOffsetColumnNumber() { return 5; }

     @Override

     protected int defineOffsetColumnPrecision() { return 11; }

     @Override

     protected int defineOffsetColumnScale() { return 12; }

     @Override

     protected int defineOffsetColumnFlags() { return 15; }

     @Override

     protected int defineOffsetColumnCompressedUnicode() { return 16; }

     @Override

     protected int defineOffsetColumnLength() { return 23; }

     @Override

     protected int defineOffsetColumnVariableTableIndex() { return 7; }

     @Override

     protected int defineOffsetColumnFixedDataOffset() { return 21; }

     @Override

     protected int defineOffsetTableDefLocation() { return 4; }

     @Override

     protected int defineOffsetRowStart() { return 14; }

     @Override

     protected int defineOffsetUsageMapStart() { return 5; }

     @Override

     protected int defineOffsetUsageMapPageData() { return 4; }

     @Override

     protected int defineOffsetReferenceMapPageNumbers() { return 1; }

     @Override

     protected int defineOffsetFreeSpace() { return 2; }

     @Override

     protected int defineOffsetNumRowsOnDataPage() { return 12; }

     @Override

     protected int defineMaxNumRowsOnDataPage() { return 255; }

     @Override

     protected int defineOffsetIndexCompressedByteCount() { return 24; }

     @Override

     protected int defineOffsetIndexEntryMask() { return 27; }

     @Override

     protected int defineOffsetPrevIndexPage() { return 12; }

     @Override

     protected int defineOffsetNextIndexPage() { return 16; }

     @Override

     protected int defineOffsetChildTailIndexPage() { return 20; }

     @Override

     protected int defineSizeIndexDefinition() { return 12; }

     @Override

     protected int defineSizeColumnHeader() { return 25; }

     @Override

     protected int defineSizeRowLocation() { return 2; }

     @Override

     protected int defineSizeLongValueDef() { return 12; }

     @Override

     protected int defineMaxInlineLongValueSize() { return 64; }

     @Override

     protected int defineMaxLongValueRowSize() { return 4076; }

     @Override

     protected int defineSizeTdefHeader() { return 63; }

     @Override

     protected int defineSizeTdefTrailer() { return 2; }

     @Override

     protected int defineSizeColumnDefBlock() { return 25; }

     @Override

     protected int defineSizeIndexEntryMask() { return 453; }

     @Override

     protected int defineUsageMapTableByteLength() { return 64; }

     @Override

     protected int defineMaxColumnsPerTable() { return 255; }

     @Override

     protected int defineMaxTableNameLength() { return 64; }

     @Override

     protected int defineMaxColumnNameLength() { return 64; }

     @Override

     protected int defineMaxIndexNameLength() { return 64; }

     @Override

     protected Charset defineCharset() { return Charset.forName("UTF-16LE"); }

   }

 }