Bug fix: If at and of leaf, then reset descending and go up again.

[idzebra-moved-to-github.git] / isamb / isamb.c

diff --git a/isamb/isamb.c b/isamb/isamb.c
index c732143..2f43971 100644 (file)
--- a/isamb/isamb.c
+++ b/isamb/isamb.c
@@ -1,4 +1,4 @@
-/* $Id: isamb.c,v 1.30 2004-06-01 12:56:38 adam Exp $
+/* $Id: isamb.c,v 1.35 2004-06-02 07:53:31 adam Exp $
    Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003,2004
    Index Data Aps
 
@@ -26,6 +26,10 @@ Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include <isamb.h>
 #include <assert.h>
 
+#ifndef ISAMB_DEBUG
+#define ISAMB_DEBUG 0
+#endif
+
 struct ISAMB_head {
     int first_block;
     int last_block;
@@ -204,6 +208,9 @@ ISAMB isamb_open (BFiles bfs, const char *name, int writeflag, ISAMC_M *method,
         assert(isamb->file[i].head.block_size == b_size);
         b_size = b_size * 4;
     }
+#if ISAMB_DEBUG
+    logf(LOG_WARN, "isamb debug enabled. Things will be slower than usual");
+#endif
     return isamb;
 }
 
@@ -1061,7 +1068,7 @@ int isamb_pp_read (ISAMB_PP pp, void *buf)
     (*pp->isamb->method->code_item)(ISAMC_DECODE, p->decodeClientData,
                                     &dst, &src);
     p->offset = src - (char*) p->bytes;
-    key_logdump_txt(LOG_DEBUG,buf, "isamb_pp_read returning 1");
+    /* key_logdump_txt(LOG_DEBUG,buf, "isamb_pp_read returning 1"); */
     return 1;
 }
 
@@ -1099,61 +1106,75 @@ int isamb_pp_forward (ISAMB_PP pp, void *buf, const void *untilbuf)
     int item_len;
     int pos;
     int nxtpos;
+    int descending=0; /* used to prevent a border condition error */
     if (!p)
         return 0;
+#if ISAMB_DEBUG
     logf(LOG_DEBUG,"isamb_pp_forward starting [%p] p=%d",pp,p->pos);
     
     (*pp->isamb->method->log_item)(LOG_DEBUG, untilbuf, "until");
     (*pp->isamb->method->log_item)(LOG_DEBUG, buf, "buf");
+#endif
 
     while (1)
     {
-        while ( p->offset == p->size) 
+        while ( (p->offset == p->size) && !descending )
         {  /* end of this block - climb higher */
+           assert (p->offset <= p->size);
+#if ISAMB_DEBUG
             logf(LOG_DEBUG,"isamb_pp_forward climbing from l=%d",
                             pp->level);
+#endif
             if (pp->level == 0)
             {
+#if ISAMB_DEBUG
                 logf(LOG_DEBUG,"isamb_pp_forward returning 0 at root");
+#endif
                 return 0; /* at end of the root, nothing left */
             }
             close_block(pp->isamb, pp->block[pp->level]);
             pp->block[pp->level]=0;
             (pp->level)--;
             p=pp->block[pp->level];
+#if ISAMB_DEBUG
             logf(LOG_DEBUG,"isamb_pp_forward climbed to node %d off=%d",
                             p->pos, p->offset);
+#endif
             assert(!p->leaf);
+           assert(p->offset <= p->size);
             /* skip the child we have handled */
             if (p->offset != p->size)
             { 
                 src = p->bytes + p->offset;
                 decode_ptr(&src, &item_len);
-               
+#if ISAMB_DEBUG                
                (*pp->isamb->method->log_item)(LOG_DEBUG, src,
                                               " isamb_pp_forward "
                                               "climb skipping old key");
+#endif
                 src += item_len;
                 decode_ptr(&src,&pos);
                 p->offset = src - (char*) p->bytes;
-                break; /* even if this puts us at the end of the block, we need to */
-                       /* descend to the last pos. UGLY coding, clean up some */
-                       /* day */
+                break; /* even if this puts us at the end of the block, we
+                         need to descend to the last pos. UGLY coding,
+                         clean up some day */
             }
         }
         if (!p->leaf)
         { 
             src = p->bytes + p->offset;
             if (p->offset == p->size)
-                cmp=-2 ; /* descend to the last node, as we have no value to cmp */
+                cmp=-2 ; /* descend to the last node, as we have
+                           no value to cmp */
             else
             {
                 decode_ptr(&src, &item_len);
-                logf(LOG_DEBUG,"isamb_pp_forward (B) on a high node. ofs=%d sz=%d nxtpos=%d ",
+#if ISAMB_DEBUG
+                logf(LOG_DEBUG,"isamb_pp_forward (B) on a high node. "
+                    "ofs=%d sz=%d nxtpos=%d ",
                         p->offset,p->size,pos);
-
-
                (*pp->isamb->method->log_item)(LOG_DEBUG, src, "");
+#endif
                 if (untilbuf)
                     cmp=(*pp->isamb->method->compare_item)(untilbuf,src);
                 else
@@ -1163,8 +1184,11 @@ int isamb_pp_forward (ISAMB_PP pp, void *buf, const void *untilbuf)
             }
             if (cmp<2)
             { 
+#if ISAMB_DEBUG
                 logf(LOG_DEBUG,"isambb_pp_forward descending l=%d p=%d ",
                             pp->level, pos);
+#endif
+                descending=1; /* prevent climbing for a while */
                 ++(pp->level);
                 p = open_block(pp->isamb,pos);
                 pp->block[pp->level] = p ;
@@ -1176,8 +1200,10 @@ int isamb_pp_forward (ISAMB_PP pp, void *buf, const void *untilbuf)
                     src = p->bytes + p->offset;
                     decode_ptr(&src,&pos);
                     p->offset=src-(char*) p->bytes;
+#if ISAMB_DEBUG
                     logf(LOG_DEBUG,"isamb_pp_forward: block %d starts with %d",
                                     p->pos, pos);
+#endif
                 } 
             } /* descend to the node */
             else
@@ -1185,46 +1211,59 @@ int isamb_pp_forward (ISAMB_PP pp, void *buf, const void *untilbuf)
                 p->offset = src - (char*) p->bytes;
                 pos=nxtpos;
                 (pp->skipped_nodes[pp->maxlevel - pp->level -1])++;
+#if ISAMB_DEBUG
                 logf(LOG_DEBUG,
-                    "isamb_pp_forward: skipping block on level %d, noting on %d (%d)",
+                    "isamb_pp_forward: skipping block on level %d, noting "
+                    "on %d (%d)",
                     pp->level, pp->maxlevel - pp->level-1 , 
                     pp->skipped_nodes[pp->maxlevel - pp->level-1 ]);
+#endif
                 /* 0 is always leafs, 1 is one level above leafs etc, no
                  * matter how high tree */
             }
         } /* not on a leaf */
         else
         { /* on a leaf */
-            src = p->bytes + p->offset;
-            dst=buf;
-            (*pp->isamb->method->code_item)(ISAMC_DECODE, p->decodeClientData,
-                                            &dst, &src);
-            p->offset = src - (char*) p->bytes;
-            if (untilbuf)
-                cmp=(*pp->isamb->method->compare_item)(untilbuf,buf);
-            else
-                cmp=-2;
-            logf(LOG_DEBUG,"isamb_pp_forward on a leaf. cmp=%d", 
-                              cmp);
-           (*pp->isamb->method->log_item)(LOG_DEBUG, buf, "");
-
-            if (cmp <2)
-            {
-                if (untilbuf)
-               {
-                   (*pp->isamb->method->log_item)(LOG_DEBUG, buf, 
-                                                  "isamb_pp_forward returning 1");
-               }
-                else
+           if (p->offset == p->size) { 
+               descending = 0;
+           }
+           else
+           {
+               assert (p->offset < p->size);
+               src = p->bytes + p->offset;
+               dst=buf;
+               (*pp->isamb->method->code_item)(ISAMC_DECODE, p->decodeClientData,
+                                               &dst, &src);
+               p->offset = src - (char*) p->bytes;
+               if (untilbuf)
+                   cmp=(*pp->isamb->method->compare_item)(untilbuf,buf);
+               else
+                   cmp=-2;
+#if ISAMB_DEBUG
+               logf(LOG_DEBUG,"isamb_pp_forward on a leaf. cmp=%d", 
+                    cmp);
+               (*pp->isamb->method->log_item)(LOG_DEBUG, buf, "");
+#endif
+               if (cmp <2)
                {
-                   (*pp->isamb->method->log_item)(LOG_DEBUG, buf, 
-                                                  "isamb_pp_read returning 1 (fwd)");
+#if ISAMB_DEBUG
+                   if (untilbuf)
+                   {
+                       (*pp->isamb->method->log_item)(
+                           LOG_DEBUG, buf,  "isamb_pp_forward returning 1");
+                   }
+                   else
+                   {
+                       (*pp->isamb->method->log_item)(
+                           LOG_DEBUG, buf, "isamb_pp_read returning 1 (fwd)");
+                   }
+#endif
+                   pp->returned_numbers++;
+                   return 1;
                }
-                pp->returned_numbers++;
-                return 1;
-            }
-            else
-                pp->skipped_numbers++;
+               else
+                   pp->skipped_numbers++;
+           }
         } /* leaf */
     } /* main loop */
 }