Changeset 54 for hw

Timestamp:

10/02/07 20:20:46 (5 years ago)

Author:

joeh

Message:

Better comments!

Location:

hw/hw2/MyStuff

Files:

• gist_private.h (modified) (1 diff)
• gistget.c (modified) (2 diffs)

hw/hw2/MyStuff/gist_private.h

@@ -56 +56 @@
 typedef struct GISTPQ
 {
-  /* fill me in! */
+  /* CS186 HW2: fill me in! */
 } GISTPQ;
 

hw/hw2/MyStuff/gistget.c

@@ -143 +143 @@
 /* insert a new priority queue entry into so->pq */
 static void
-gist_pq_insertpq(GISTScanOpaque so, GISTPQ *newpq)
+gist_pq_insertpq(GISTScanOpaque so, /* State of a GiST scan */
+                 GISTPQ *newpq /* a new GISTPQ entry */
+                 )
 {
   /* CS186 HW2: fill me in! */
@@ -150 +152 @@
 /* 
  * given the current state of the index scan, generate a GISTPQ to insert into
- * the priority queue, and insert it.
+ * the priority queue, and insert it. Note that the "stack" holds the blocks
+ * from the root to the current item.
+ * There are two cases to consider: 
+ *   1) the item being inserted is an entry in a leaf node, identified by a
+ *      block number (from the stack), and the offset.  It points to a data
+ *      item in the database (isdata == true).
+ *   2) the item being inserted is the block number of an index node to 
+ *      be visited next (isdata == false).  The key corresponding to this 
+ *      block number is in the block's *parent* in the tree (which can be
+ *      found in the stack) at the given offset.
  */
 static void