X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=isam%2Fmemory.c;h=027b72cb87efdf0383b82c9e71f0d6dca00be944;hb=b8d492961ba89859e02543581d097b75a59b546c;hp=475b5fc01a7ab8a1eedd1808a3a13e5d92f696d4;hpb=fa2e85c18627b18737723d91e08c752d9931f589;p=idzebra-moved-to-github.git

diff --git a/isam/memory.c b/isam/memory.c
index 475b5fc..027b72c 100644
--- a/isam/memory.c
+++ b/isam/memory.c
@@ -4,7 +4,23 @@
  * Sebastian Hammer, Adam Dickmeiss
  *
  * $Log: memory.c,v $
- * Revision 1.8  1995-12-06 14:48:27  quinn
+ * Revision 1.13  1996-03-20 13:29:16  quinn
+ * Bug-fix
+ *
+ * Revision 1.12  1996/03/11  14:52:23  quinn
+ * Fixed update bug. Repeated insertion in the same area sometimes caused
+ * problems.
+ *
+ * Revision 1.11  1996/02/10  12:20:58  quinn
+ * *** empty log message ***
+ *
+ * Revision 1.10  1995/12/12  14:12:47  quinn
+ * *** empty log message ***
+ *
+ * Revision 1.9  1995/12/06  15:48:46  quinn
+ * Fixed update-problem.
+ *
+ * Revision 1.8  1995/12/06  14:48:27  quinn
  * Fixed some strange bugs.
  *
  * Revision 1.7  1995/12/06  09:59:46  quinn
@@ -145,6 +161,7 @@ void is_m_establish_tab(ISAM is, is_mtable *tab, ISAM_P pos)
 	tab->data->data = 0;
 	tab->cur_mblock = tab->data;
 	tab->cur_mblock->cur_mbuf = 0;
+	tab->last_mbuf = 0;
     }
     else /* new block */
     {
@@ -157,6 +174,7 @@ void is_m_establish_tab(ISAM is, is_mtable *tab, ISAM_P pos)
 	tab->cur_mblock = tab->data;
 	tab->cur_mblock->cur_mbuf = tab->data->data;
 	tab->cur_mblock->cur_mbuf->cur_record = 0;
+	tab->last_mbuf = 0;
     }
     tab->is = is;
 }
@@ -227,18 +245,28 @@ void is_m_delete_record(is_mtable *tab)
     	mbuf->num--;
     	mbuf->cur_record--;
     }
-    else /* middle of a block */
+    else if (mbuf->cur_record == 1) /* beginning of mbuf */
+    {
+	mbuf->num--;
+	mbuf->offset +=is_keysize(tab->is);
+	mbuf->cur_record = 0;
+    }
+    else /* middle of mbuf */
     {
+	/* insert block after current one */
 	new = xmalloc_mbuf(IS_MBUF_TYPE_SMALL);
 	new->next = mbuf->next;
 	mbuf->next = new;
+
+	/* virtually transfer everything after current record to new one. */
 	new->data = mbuf->data;
 	mbuf->refcount++;
 	new->offset = mbuf->offset + mbuf->cur_record * is_keysize(tab->is);
 	new->num = mbuf->num - mbuf->cur_record;
+	
+	/* old buf now only contains stuff before current record */
 	mbuf->num = mbuf->cur_record -1;
-	mbuf = mbuf->next;
-	mbuf->cur_record = 0;
+	tab->cur_mblock->cur_mbuf = new;
     }
     tab->num_records--;
     tab->cur_mblock->num_records--;
@@ -282,7 +310,9 @@ int is_m_write_record(is_mtable *tab, const void *rec)
 	mbuf = tab->cur_mblock->cur_mbuf = mbuf->next;
 	mbuf->cur_record = 0;
     }
+    /*
     logf (LOG_DEBUG, "is_m_write_rec(rec == %d)", mbuf->cur_record);
+    */
     memcpy(mbuf->data + mbuf->offset + mbuf->cur_record * is_keysize(tab->is),
 	rec, is_keysize(tab->is));
     mbuf->num++;
@@ -296,7 +326,10 @@ int is_m_write_record(is_mtable *tab, const void *rec)
 void is_m_unread_record(is_mtable *tab)
 {
     assert(tab->cur_mblock->cur_mbuf->cur_record);
-    tab->cur_mblock->cur_mbuf->cur_record--;
+    if (tab->last_mbuf)
+	tab->cur_mblock->cur_mbuf = tab->last_mbuf;
+    else
+	tab->cur_mblock->cur_mbuf->cur_record--;
 }
 
 /*
@@ -337,7 +370,7 @@ int is_m_peek_record(is_mtable *tab, void *rec)
     return 1;
 }
 
-int is_m_read_record(is_mtable *tab, void *buf)
+int is_m_read_record(is_mtable *tab, void *buf, int keep)
 {
     is_mbuf *mbuf;
 
@@ -350,7 +383,7 @@ int is_m_read_record(is_mtable *tab, void *buf)
     {
 	if (!mbuf->next) /* end of mblock */
 	{
-	    if (tab->cur_mblock->state == IS_MBSTATE_CLEAN &&
+	    if (!keep && tab->cur_mblock->state == IS_MBSTATE_CLEAN &&
 		tab->cur_mblock->diskpos > 0)
 	    {
 		xfree_mbufs(tab->cur_mblock->data);
@@ -364,14 +397,20 @@ int is_m_read_record(is_mtable *tab, void *buf)
 		    if (read_current_full(tab, tab->cur_mblock) < 0)
 			return -1;
 		tab->cur_mblock->cur_mbuf = mbuf = tab->cur_mblock->data;
+		tab->last_mbuf = 0;
 	    }
 	    else
 	    	return 0;   /* EOTable */
 	}
 	else
+	{
+	    tab->last_mbuf = mbuf;
 	    tab->cur_mblock->cur_mbuf = mbuf = mbuf->next;
+	}
 	mbuf->cur_record = 0;
     }
+    else
+	tab->last_mbuf = 0;
     memcpy(buf, mbuf->data + mbuf->offset + mbuf->cur_record *
 	is_keysize(tab->is), is_keysize(tab->is));
     mbuf->cur_record++;
@@ -388,12 +427,12 @@ int is_m_seek_record(is_mtable *tab, const void *rec)
 
     for (;;)
     {
-	if (is_m_read_record(tab, &peek) <= 0)
+	if (is_m_read_record(tab, &peek, 1) <= 0)
 	    return 1;
 	if ((rs = (*tab->is->cmp)(peek, rec)) > 0)
 	{
 	    is_m_unread_record(tab);
-	    return 1;
+	    return rs;
 	}
 	else if (rs == 0)
 	    return 0;