Added detailed comments

git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@352727 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 19 insertions, 4 deletions

diff --git a/src/scratchpad/src/org/apache/poi/hdf/model/hdftypes/FormattedDiskPage.java b/src/scratchpad/src/org/apache/poi/hdf/model/hdftypes/FormattedDiskPage.java
index 6741b4e0e8..ca45da4236 100644
--- a/src/scratchpad/src/org/apache/poi/hdf/model/hdftypes/FormattedDiskPage.java
+++ b/src/scratchpad/src/org/apache/poi/hdf/model/hdftypes/FormattedDiskPage.java
@@ -61,12 +61,25 @@ import org.apache.poi.util.LittleEndian;
  * grpprls of the paragraph and character properties of the document. A grpprl
  * is a list of sprms(decompression operations) to perform on a parent style.
  *
+ * The style properties for paragraph and character runs
+ * are stored in fkps. There are PAP fkps for paragraph properties and CHP fkps
+ * for character run properties. The first part of the fkp for both CHP and PAP
+ * fkps consists of an array of 4 byte int offsets in the main stream for that
+ * Paragraph's or Character run's text. The ending offset is the next
+ * value in the array. For example, if an fkp has X number of Paragraph's
+ * stored in it then there are (x + 1) 4 byte ints in the beginning array. The
+ * number X is determined by the last byte in a 512 byte fkp.
+ *
+ * CHP and PAP fkps also store the compressed styles(grpprl) that correspond to
+ * the offsets on the front of the fkp. The offset of the grpprls is determined
+ * differently for CHP fkps and PAP fkps.
+ *
  * @author Ryan Ackley
  */
-public class FormattedDiskPage
+public abstract class FormattedDiskPage
 {
-    byte[] _fkp;
-    int _crun;
+    protected byte[] _fkp;
+    protected int _crun;
 
     /**
      * Uses a 512-byte array to create a FKP
@@ -97,8 +110,10 @@ public class FormattedDiskPage
      * Used to get the total number of grrprl's stored int this FKP
      * @return The number of grpprls in this FKP
      */
-    public int getSize()
+    public int size()
     {
         return _crun;
     }
+
+    public abstract byte[] getGrpprl(int index);
 }
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