add support for sharing backing index data across indexes during table creation

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/branches/mutateops@994 f203690c-595d-4dc9-a70b-905162fa7fd2

4 files changed, 98 insertions, 17 deletions

diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/IndexData.java b/src/main/java/com/healthmarketscience/jackcess/impl/IndexData.java
index e5e6dc7..090baf0 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/IndexData.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/IndexData.java
@@ -501,10 +501,11 @@ public class IndexData {
     writeDataPage(rootPageBuffer, NEW_ROOT_DATA_PAGE, 
                   creator.getTdefPageNumber(), creator.getFormat());
 
-    for(IndexBuilder idx : creator.getIndexes()) {
+    for(TableCreator.IndexDataState idxDataState : creator.getIndexDataStates()) {
       buffer.putInt(MAGIC_INDEX_NUMBER); // seemingly constant magic value
 
       // write column information (always MAX_COLUMNS entries)
+      IndexBuilder idx = idxDataState.getIndex();
       List<IndexBuilder.Column> idxColumns = idx.getColumns();
       for(int i = 0; i < MAX_COLUMNS; ++i) {
 
@@ -537,16 +538,14 @@ public class IndexData {
         buffer.put(flags); // column flags (e.g. ordering)
       }
 
-      TableCreator.IndexState idxState = creator.getIndexState(idx);
-
-      buffer.put(idxState.getUmapRowNumber()); // umap row
+      buffer.put(idxDataState.getUmapRowNumber()); // umap row
       ByteUtil.put3ByteInt(buffer, creator.getUmapPageNumber()); // umap page
 
       // write empty root index page
       creator.getPageChannel().writePage(rootPageBuffer, 
-                                         idxState.getRootPageNumber());
+                                         idxDataState.getRootPageNumber());
 
-      buffer.putInt(idxState.getRootPageNumber());
+      buffer.putInt(idxDataState.getRootPageNumber());
       buffer.putInt(0); // unknown
       buffer.put(idx.getFlags()); // index flags (unique, etc.)
       ByteUtil.forward(buffer, 5); // unknown
diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/IndexImpl.java b/src/main/java/com/healthmarketscience/jackcess/impl/IndexImpl.java
index f3fe868..41eb669 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/IndexImpl.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/IndexImpl.java
@@ -345,7 +345,7 @@ public class IndexImpl implements Index, Comparable<IndexImpl>
       TableCreator.IndexState idxState = creator.getIndexState(idx);
       buffer.putInt(TableImpl.MAGIC_TABLE_NUMBER); // seemingly constant magic value which matches the table def
       buffer.putInt(idxState.getIndexNumber()); // index num
-      buffer.putInt(idxState.getIndexDataNumber()); // index data num
+      buffer.putInt(idxState.getIndexDataState().getIndexDataNumber()); // index data num
       buffer.put((byte)0); // related table type
       buffer.putInt(INVALID_INDEX_NUMBER); // related index num
       buffer.putInt(0); // related table definition page number
diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/TableCreator.java b/src/main/java/com/healthmarketscience/jackcess/impl/TableCreator.java
index 89da310..a58622f 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/TableCreator.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/TableCreator.java
@@ -43,6 +43,8 @@ class TableCreator extends DBMutator
   private final List<IndexBuilder> _indexes;
   private final Map<IndexBuilder,IndexState> _indexStates = 
     new IdentityHashMap<IndexBuilder,IndexState>();
+  private final List<IndexDataState> _indexDataStates = 
+    new ArrayList<IndexDataState>();
   private final Map<ColumnBuilder,ColumnState> _columnStates = 
     new IdentityHashMap<ColumnBuilder,ColumnState>();
   private final List<ColumnBuilder> _lvalCols = new ArrayList<ColumnBuilder>();
@@ -96,6 +98,10 @@ class TableCreator extends DBMutator
     return _indexStates.get(idx);
   }
 
+  public List<IndexDataState> getIndexDataStates() {
+    return _indexDataStates;
+  }
+
   public ColumnState getColumnState(ColumnBuilder col) {
     return _columnStates.get(col);
   }
@@ -145,7 +151,7 @@ class TableCreator extends DBMutator
       for(IndexBuilder idx : _indexes) {
         IndexState idxState = new IndexState();
         idxState.setIndexNumber(_logicalIndexCount++);
-        idxState.setIndexDataNumber(_indexCount++);
+        idxState.setIndexDataState(findIndexDataState(idx));
         _indexStates.put(idx, idxState);
       }
     }
@@ -169,6 +175,24 @@ class TableCreator extends DBMutator
     }
   }
 
+  private IndexDataState findIndexDataState(IndexBuilder idx) {
+
+    // search for an index which matches the given index (in terms of the
+    // backing data)
+    for(IndexDataState idxDataState : _indexDataStates) {
+      if(sameIndexData(idxDataState.getIndex(), idx)) {
+        return idxDataState;
+      }
+    }
+
+    // no matches found, need new index data state
+    IndexDataState idxDataState = new IndexDataState();
+    idxDataState.setIndex(idx);
+    idxDataState.setIndexDataNumber(_indexCount++);
+    _indexDataStates.add(idxDataState);
+    return idxDataState;
+  }
+
   /**
    * Validates the new table information before attempting creation.
    */
@@ -241,6 +265,35 @@ class TableCreator extends DBMutator
     return autoCols;
   }
 
+  private static boolean sameIndexData(IndexBuilder idx1, IndexBuilder idx2) {
+    // index data can be combined if flags match and columns (and col flags)
+    // match
+    if(idx1.getFlags() != idx2.getFlags()) {
+      return false;
+    }
+
+    if(idx1.getColumns().size() != idx2.getColumns().size()) {
+      return false;
+    }
+    
+    for(int i = 0; i < idx1.getColumns().size(); ++i) {
+      IndexBuilder.Column col1 = idx1.getColumns().get(i);
+      IndexBuilder.Column col2 = idx2.getColumns().get(i);
+
+      if(!sameIndexData(col1, col2)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  private static boolean sameIndexData(
+      IndexBuilder.Column col1, IndexBuilder.Column col2) {
+    return (col1.getName().equals(col2.getName()) && 
+            (col1.getFlags() == col2.getFlags()));
+  }
+
   /**
    * Maintains additional state used during index creation.
    * @usage _advanced_class_
@@ -248,10 +301,7 @@ class TableCreator extends DBMutator
   static final class IndexState
   {
     private int _indexNumber;
-    private int _indexDataNumber;
-    private byte _umapRowNumber;
-    private int _umapPageNumber;
-    private int _rootPageNumber;
+    private IndexDataState _dataState;
 
     public int getIndexNumber() {
       return _indexNumber;
@@ -261,6 +311,38 @@ class TableCreator extends DBMutator
       _indexNumber = newIndexNumber;
     }
 
+    public IndexDataState getIndexDataState() {
+      return _dataState;
+    }
+
+    public void setIndexDataState(IndexDataState dataState) {
+      _dataState = dataState;
+    }
+  }
+    
+  /**
+   * Maintains additional state used during index data creation.
+   * @usage _advanced_class_
+   */
+  static final class IndexDataState
+  {
+    // all indexes which have the same backing IndexDataState will have
+    // equivalent columns and flags.  we keep a reference to the first index
+    // which uses this backing index data.
+    private IndexBuilder _idx;
+    private int _indexDataNumber;
+    private byte _umapRowNumber;
+    private int _umapPageNumber;
+    private int _rootPageNumber;
+
+    public IndexBuilder getIndex() {
+      return _idx;
+    }
+
+    public void setIndex(IndexBuilder idx) {
+      _idx = idx;
+    }
+
     public int getIndexDataNumber() {
       return _indexDataNumber;
     }
diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/TableImpl.java b/src/main/java/com/healthmarketscience/jackcess/impl/TableImpl.java
index 18fee24..1a3d19f 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/TableImpl.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/TableImpl.java
@@ -1503,16 +1503,16 @@ public class TableImpl implements Table
 
         // index umap
         int indexIdx = i - 2;
-        IndexBuilder idx = creator.getIndexes().get(indexIdx);
+        TableCreator.IndexDataState idxDataState = 
+          creator.getIndexDataStates().get(indexIdx);
         
         // allocate root page for the index
         int rootPageNumber = pageChannel.allocateNewPage();
 
         // stash info for later use
-        TableCreator.IndexState idxState = creator.getIndexState(idx);
-        idxState.setRootPageNumber(rootPageNumber);
-        idxState.setUmapRowNumber((byte)umapRowNum);
-        idxState.setUmapPageNumber(umapPageNumber);
+        idxDataState.setRootPageNumber(rootPageNumber);
+        idxDataState.setUmapRowNumber((byte)umapRowNum);
+        idxDataState.setUmapPageNumber(umapPageNumber);
 
         // index map definition, including initial root page
         umapBuf.put(rowStart, UsageMap.MAP_TYPE_INLINE);