fix: support Russian collating sort order (LCID 1049) for text indexes

src/main/java/io/github/spannm/jackcess/impl/ColumnImpl.java

@@ -147,6 +147,17 @@ public class ColumnImpl implements Column, Comparable<ColumnImpl>, DateTimeConte
      */
     public static final SortOrder        GENERAL_SORT_ORDER               = new SortOrder(GENERAL_SORT_ORDER_VALUE, 1);
 
+    /**
+     * Sort order used by MS Access databases configured with the Russian/Cyrillic collation (LCID 1049, version 0).
+     * <p>
+     * Index entries for this sort order are encoded by {@code IndexData.RussianTextColumnDescriptor}, which
+     * currently delegates to {@link GeneralLegacyIndexCodes} as a structurally compatible interim solution
+     * until the proprietary Russian byte tables are reverse-engineered.
+     *
+     * @see IndexData
+     */
+    public static final SortOrder        RUSSIAN_SORT_ORDER               = new SortOrder((short) 1049, 0);
+
     /**
      * Sort order used by MS Access databases configured with the Turkish collation (LCID 1055, version 0).
      * <p>
@@ -2364,8 +2375,13 @@ public DataType getType() {
      *   <tr><td>{@link #GENERAL_97_SORT_ORDER}</td><td>1033</td><td>−1</td><td>Access 97</td></tr>
      *   <tr><td>{@link #GENERAL_LEGACY_SORT_ORDER}</td><td>1033</td><td>0</td><td>Access 2000–2007</td></tr>
      *   <tr><td>{@link #GENERAL_SORT_ORDER}</td><td>1033</td><td>1</td><td>Access 2010+</td></tr>
+     *   <tr><td>{@link #TURKISH_SORT_ORDER}</td><td>1055</td><td>0</td><td>Turkish (interim)</td></tr>
+     *   <tr><td>{@link #RUSSIAN_SORT_ORDER}</td><td>1049</td><td>0</td><td>Russian (interim)</td></tr>
      * </table>
-     * Any other {@code SortOrder} (e.g. Turkish, LCID 1055) causes the backing {@link IndexData} to become
+     * For the Turkish and Russian sort orders, the backing {@link IndexData} encodes text using a structurally
+     * compatible but semantically approximate format (via GeneralLegacyIndexCodes) until the proprietary byte
+     * tables are reverse-engineered; see {@link IndexData#setUnsupportedReason} and the respective descriptor
+     * Javadoc. Any other (unrecognized) {@code SortOrder} causes the backing {@link IndexData} to become
      * read-only for write operations; see {@link IndexData#setUnsupportedReason}.
      * <p>
      * Sort orders are read via {@link ColumnImpl#readSortOrder} and written via

src/main/java/io/github/spannm/jackcess/impl/IndexData.java

@@ -49,11 +49,13 @@
  *         <li>{@link ColumnImpl#GENERAL_SORT_ORDER} – "General" (Access 2010+, LCID 1033, version 1)</li>
  *         <li>{@link ColumnImpl#GENERAL_LEGACY_SORT_ORDER} – "General Legacy" (Access 2000–2007, LCID 1033, version 0)</li>
  *         <li>{@link ColumnImpl#GENERAL_97_SORT_ORDER} – "General" (Access 97, LCID 1033, version −1)</li>
+ *         <li>{@link ColumnImpl#RUSSIAN_SORT_ORDER} – Russian/Cyrillic (LCID 1049, version 0)</li>
+ *         <li>{@link ColumnImpl#TURKISH_SORT_ORDER} – Turkish (LCID 1055, version 0)</li>
  *       </ul>
  *       Any other sort order causes the index to be marked <em>read-only</em> via {@link #setUnsupportedReason}; write operations
  *       will throw {@link UnsupportedOperationException}. This is the root cause of
- *       <a href="https://github.com/spannm/ucanaccess/issues/35">UCanAccess issue #35</a> for Turkish databases
- *       (SortOrder 1055).
+ *       <a href="https://github.com/spannm/ucanaccess/issues/35">UCanAccess issue #35</a> for databases with unsupported collations
+ *       (e.g. Turkish LCID 1055, Russian LCID 1049).
  *   </li>
  * </ul>
  *
@@ -1385,6 +1387,8 @@ private static Entry createSpecialEntry(RowIdImpl rowId) {
      *       <td>{@link GenLegTextColumnDescriptor}</td><td>Access 2000–2007</td></tr>
      *   <tr><td>{@link ColumnImpl#GENERAL_97_SORT_ORDER}</td><td>1033</td><td>-1</td>
      *       <td>{@link Gen97TextColumnDescriptor}</td><td>Access 97</td></tr>
+     *   <tr><td>{@link ColumnImpl#RUSSIAN_SORT_ORDER}</td><td>1049</td><td>0</td>
+     *       <td>{@link RussianTextColumnDescriptor}</td><td>any (Russian/Cyrillic collation)</td></tr>
      *   <tr><td>{@link ColumnImpl#TURKISH_SORT_ORDER}</td><td>1055</td><td>0</td>
      *       <td>{@link TurkishTextColumnDescriptor}</td><td>any (Turkish collation)</td></tr>
      *   <tr><td>any other (e.g. Arabic 1025, Greek 1032)</td><td>–</td><td>–</td>
@@ -1418,6 +1422,8 @@ private ColumnDescriptor newColumnDescriptor(ColumnImpl col, byte flags) {
                     return new GenLegTextColumnDescriptor(col, flags);
                 } else if (ColumnImpl.GENERAL_97_SORT_ORDER.equals(sortOrder)) {
                     return new Gen97TextColumnDescriptor(col, flags);
+                } else if (ColumnImpl.RUSSIAN_SORT_ORDER.equals(sortOrder)) {
+                    return new RussianTextColumnDescriptor(col, flags);
                 } else if (ColumnImpl.TURKISH_SORT_ORDER.equals(sortOrder)) {
                     return new TurkishTextColumnDescriptor(col, flags);
                 }
@@ -1858,6 +1864,49 @@ protected void writeNonNullValue(Object value, ByteStream bout) throws IOExcepti
         }
     }
 
+    /**
+     * {@link ColumnDescriptor} for text columns using the Russian/Cyrillic sort order (LCID 1049, version 0).
+     * <p>
+     * <strong>Implementation note – structural compatibility over semantic accuracy:</strong><br>
+     * MS Access stores index entries in a proprietary, order-preserving byte format that is specific to each
+     * collation. The exact byte tables for the Russian collation have not yet been reverse-engineered.
+     * Using a standard JVM {@link java.text.Collator} key ({@code CollationKey.toByteArray()}) is
+     * <em>not</em> an option: the ICU/CLDR sort-key format is fundamentally different from the MS Access
+     * format, and index pages written with JVM keys would be unreadable by MS Access (corrupted index).
+     * <p>
+     * As a pragmatic interim solution this descriptor delegates to
+     * {@link GeneralLegacyIndexCodes#GEN_LEG_INSTANCE}, which produces structurally valid MS Access index
+     * bytes. The trade-off:
+     * <ul>
+     *   <li><b>Pro:</b> index pages are structurally correct and can be read by MS Access without errors.
+     *       A subsequent "Compact &amp; Repair" in MS Access will rebuild the index with proper Russian
+     *       collation weights.</li>
+     *   <li><b>Con:</b> Russian/Cyrillic-specific collation rules are not honoured in the written index.
+     *       Index-based ORDER BY and range queries on Russian text may therefore return results in
+     *       General-Legacy rather than Russian order.</li>
+     * </ul>
+     * <p>
+     * Once the Russian byte tables are available, this class should be replaced by a dedicated
+     * {@code RussianIndexCodes} implementation that encodes entries with full Russian collation semantics,
+     * analogous to {@link GeneralLegacyIndexCodes} for the General sort order.
+     *
+     * @see ColumnImpl#RUSSIAN_SORT_ORDER
+     * @see GeneralLegacyIndexCodes
+     */
+    private static final class RussianTextColumnDescriptor extends ColumnDescriptor {
+        private RussianTextColumnDescriptor(ColumnImpl column, byte flags) {
+            super(column, flags);
+        }
+
+        @Override
+        protected void writeNonNullValue(Object value, ByteStream bout) throws IOException {
+            // Delegate to General-Legacy encoding to produce structurally valid MS Access index bytes.
+            // Russian/Cyrillic-specific collation weights are not yet supported.
+            // See class-level Javadoc for details and the path to a full implementation.
+            GeneralLegacyIndexCodes.GEN_LEG_INSTANCE.writeNonNullIndexTextValue(value, bout, isAscending());
+        }
+    }
+
     /**
      * ColumnDescriptor for guid columns.
      */