[github-182] Fix root property size calculation. Thanks to netmackan. This closes #182

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1878721 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/poifs/filesystem/POIFSMiniStore.java

@@ -252,7 +252,7 @@ public class POIFSMiniStore extends BlockStore
           if (!sbat.hasFreeSectors()) {
               blocksUsed += _filesystem.getBigBlockSizeDetails().getBATEntriesPerBlock();
           } else {
-              blocksUsed += sbat.getUsedSectors(false);
+              blocksUsed += sbat.getOccupiedSize();
           }
        }
        // Set the size on the root in terms of the number of SBAT blocks

src/java/org/apache/poi/poifs/storage/BATBlock.java

@@ -192,6 +192,27 @@ public final class BATBlock implements BlockWritable {
         return usedSectors;
     }
 
+    /**
+     * How much of this block is occupied?.
+     * This counts the number of sectors up and including the last used sector.
+     * Note that this is different from {@link #getUsedSectors(boolean)} which
+     * could be smaller as it does not count unused sectors where there are
+     * used ones after it (i.e. fragmentation).
+     *
+     * @since POI 5.0.0
+     */
+    public int getOccupiedSize() {
+        int usedSectors = _values.length;
+        for (int k = _values.length - 1; k >= 0; k--) {
+            if(_values[k] == POIFSConstants.UNUSED_BLOCK) {
+                usedSectors--;
+            } else {
+                break;
+            }
+        }
+        return usedSectors;
+    }
+
     public int getValueAt(int relativeOffset) {
        if(relativeOffset >= _values.length) {
           throw new ArrayIndexOutOfBoundsException(
@@ -201,6 +222,7 @@ public final class BATBlock implements BlockWritable {
        }
        return _values[relativeOffset];
     }
+
     public void setValueAt(int relativeOffset, int value) {
        int oldValue = _values[relativeOffset];
        _values[relativeOffset] = value;
@@ -221,6 +243,7 @@ public final class BATBlock implements BlockWritable {
     public void setOurBlockIndex(int index) {
        this.ourBlockIndex = index;
     }
+
     /**
      * Retrieve where in the file we live
      */
@@ -237,7 +260,6 @@ public final class BATBlock implements BlockWritable {
      * @exception IOException on problems writing to the specified
      *            stream
      */
-
     public void writeBlocks(final OutputStream stream) throws IOException {
         // Save it out
         stream.write( serialize() );

src/testcases/org/apache/poi/poifs/storage/TestBATBlock.java

@@ -176,6 +176,67 @@ public final class TestBATBlock {
         assertEquals(1023, block4096.getUsedSectors(true));
     }
 
+    @Test
+    public void testOccupiedSize() {
+        POIFSBigBlockSize b512 = POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS;
+        POIFSBigBlockSize b4096 = POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS;
+
+        // Try first with 512 block sizes, which can hold 128 entries
+        BATBlock block512 = BATBlock.createEmptyBATBlock(b512, false);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(0, block512.getUsedSectors(false));
+
+        // Allocate a few
+        block512.setValueAt(0, 42);
+        block512.setValueAt(10, 42);
+        block512.setValueAt(20, 42);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(21, block512.getOccupiedSize());
+
+        // Release one in the middle should not lower size
+        block512.setValueAt(10, POIFSConstants.UNUSED_BLOCK);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(21, block512.getOccupiedSize());
+
+        // Release the last one should lower the size
+        block512.setValueAt(20, POIFSConstants.UNUSED_BLOCK);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(1, block512.getOccupiedSize());
+
+        // Release first one should lower the size
+        block512.setValueAt(0, POIFSConstants.UNUSED_BLOCK);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(0, block512.getOccupiedSize());
+
+        // Set the last one
+        block512.setValueAt(127, 42);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(128, block512.getOccupiedSize());
+
+        block512.setValueAt(126, 42);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(128, block512.getOccupiedSize());
+
+        block512.setValueAt(127, POIFSConstants.UNUSED_BLOCK);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(127, block512.getOccupiedSize());
+
+        // Allocate all
+        for (int i = 0; i < b512.getBATEntriesPerBlock(); i++) {
+            block512.setValueAt(i, 82);
+        }
+        // Check
+        assertFalse(block512.hasFreeSectors());
+        assertEquals(128, block512.getOccupiedSize());
+
+        // Release some in the beginning should not lower size
+        block512.setValueAt(0, POIFSConstants.UNUSED_BLOCK);
+        block512.setValueAt(1, POIFSConstants.UNUSED_BLOCK);
+        block512.setValueAt(13, POIFSConstants.UNUSED_BLOCK);
+        assertTrue(block512.hasFreeSectors());
+        assertEquals(128, block512.getOccupiedSize());
+    }
+
     @Test
     public void testGetBATBlockAndIndex() {
         HeaderBlock header = new HeaderBlock(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);