Fixed bug #305: Scan with preferredPositionInResponse <= -2 crashes.

diff --git a/index/zrpn.c b/index/zrpn.c
index 87190e1..325c066 100644 (file)
--- a/index/zrpn.c
+++ b/index/zrpn.c
@@ -1,4 +1,4 @@
-/* $Id: zrpn.c,v 1.182 2005-04-29 10:54:45 adam Exp $
+/* $Id: zrpn.c,v 1.183 2005-04-29 18:38:50 adam Exp $
    Copyright (C) 1995-2005
    Index Data ApS
 
@@ -2598,6 +2598,7 @@ static int scan_handle (char *name, const char *info, int pos, void *client)
        idx = scan_info->after - pos + scan_info->before;
     else
         idx = - pos - 1;
+
     if (idx < 0)
        return 0;
     scan_info->list[idx].term = (char *)
@@ -2818,19 +2819,17 @@ ZEBRA_RES rpn_scan(ZebraHandle zh, ODR stream, Z_AttributesPlusTerm *zapt,
         return ZEBRA_OK;
     }
     /* prepare dictionary scanning */
-    if (pos < 1 || pos > num)
-    {
-       zh->errCode = YAZ_BIB1_SCAN_UNSUPP_VALUE_OF_POSITION_IN_RESPONSE;
-       *num_entries = 0;
-       return ZEBRA_FAIL;
-    }
     if (num < 1)
     {
        *num_entries = 0;
        return ZEBRA_OK;
     }
     before = pos-1;
+    if (before < 0)
+       before = 0;
     after = 1+num-pos;
+    if (after < 0)
+       after = 0;
     yaz_log(YLOG_DEBUG, "rpn_scan pos=%d num=%d before=%d "
            "after=%d before+after=%d",
            pos, num, before, after, before+after);
@@ -2880,8 +2879,10 @@ ZEBRA_RES rpn_scan(ZebraHandle zh, ODR stream, Z_AttributesPlusTerm *zapt,
         int j, j0 = -1;
         const char *mterm = NULL;
         const char *tst;
-        RSET rset;
-        
+        RSET rset = 0;
+       int lo = i + pos-1; /* offset in result list */
+
+       /* find: j0 is the first of the minimal values */
         for (j = 0; j < ord_no; j++)
         {
             if (ptr[j] < before+after && ptr[j] >= 0 &&
@@ -2893,45 +2894,61 @@ ZEBRA_RES rpn_scan(ZebraHandle zh, ODR stream, Z_AttributesPlusTerm *zapt,
             }
         }
         if (j0 == -1)
-            break;
-        scan_term_untrans(zh, stream->mem, reg_id,
-                         &glist[i+before].term, mterm);
-        rset = rset_trunc(zh, &scan_info_array[j0].list[ptr[j0]].isam_p, 1,
-                         glist[i+before].term, strlen(glist[i+before].term),
-                         NULL, 0, zapt->term->which, rset_nmem, 
-                         key_it_ctrl,key_it_ctrl->scope);
-        ptr[j0]++;
+            break;  /* no value found, stop */
+
+       /* get result set for first one , but only if it's within bounds */
+       if (lo >= 0)
+       {
+           /* get result set for first term */
+           scan_term_untrans(zh, stream->mem, reg_id,
+                             &glist[lo].term, mterm);
+           rset = rset_trunc(zh, &scan_info_array[j0].list[ptr[j0]].isam_p, 1,
+                             glist[lo].term, strlen(glist[lo].term),
+                             NULL, 0, zapt->term->which, rset_nmem, 
+                             key_it_ctrl,key_it_ctrl->scope);
+       }
+       ptr[j0]++; /* move index for this set .. */
+       /* get result set for remaining scan terms */
         for (j = j0+1; j<ord_no; j++)
         {
             if (ptr[j] < before+after && ptr[j] >= 0 &&
                 (tst = scan_info_array[j].list[ptr[j]].term) &&
                 !strcmp (tst, mterm))
             {
-                RSET rsets[2];
-               
-               rsets[0] = rset;
-                rsets[1] =
-                   rset_trunc(zh, &scan_info_array[j].list[ptr[j]].isam_p, 1,
-                              glist[i+before].term,
-                              strlen(glist[i+before].term), NULL, 0,
-                              zapt->term->which,rset_nmem,
-                              key_it_ctrl, key_it_ctrl->scope);
-                rset = rsmulti_or_create(rset_nmem, key_it_ctrl,
-                                        2, key_it_ctrl->scope, rsets);
+               if (lo >= 0)
+               {
+                   RSET rsets[2];
+                   
+                   rsets[0] = rset;
+                   rsets[1] =
+                       rset_trunc(
+                           zh, &scan_info_array[j].list[ptr[j]].isam_p, 1,
+                           glist[lo].term,
+                           strlen(glist[lo].term), NULL, 0,
+                           zapt->term->which,rset_nmem,
+                           key_it_ctrl, key_it_ctrl->scope);
+                   rset = rsmulti_or_create(rset_nmem, key_it_ctrl,
+                                            2, key_it_ctrl->scope, rsets);
+               }
                 ptr[j]++;
             }
         }
-        if (limit_set)
+       if (lo >= 0)
        {
-           RSET rsets[2];
-           rsets[0] = rset;
-           rsets[1] = rset_dup(limit_set);
-           
-           rset = rsmulti_and_create(rset_nmem, key_it_ctrl,
-                                     key_it_ctrl->scope, 2, rsets);
+           /* merge with limit_set if given */
+           if (limit_set)
+           {
+               RSET rsets[2];
+               rsets[0] = rset;
+               rsets[1] = rset_dup(limit_set);
+               
+               rset = rsmulti_and_create(rset_nmem, key_it_ctrl,
+                                         key_it_ctrl->scope, 2, rsets);
+           }
+           /* count it */
+           count_set(rset, &glist[lo].occurrences);
+           rset_delete(rset);
        }
-       count_set(rset, &glist[i+before].occurrences);
-       rset_delete(rset);
     }
     if (i < after)
     {
@@ -2948,6 +2965,7 @@ ZEBRA_RES rpn_scan(ZebraHandle zh, ODR stream, Z_AttributesPlusTerm *zapt,
        const char *mterm = NULL;
        const char *tst;
        RSET rset;
+       int lo = before-1-i; /* offset in result list */
        
        for (j = 0; j <ord_no; j++)
        {
@@ -2963,11 +2981,11 @@ ZEBRA_RES rpn_scan(ZebraHandle zh, ODR stream, Z_AttributesPlusTerm *zapt,
            break;
        
        scan_term_untrans (zh, stream->mem, reg_id,
-                          &glist[before-1-i].term, mterm);
+                          &glist[lo].term, mterm);
        
        rset = rset_trunc
            (zh, &scan_info_array[j0].list[before-1-ptr[j0]].isam_p, 1,
-            glist[before-1-i].term, strlen(glist[before-1-i].term),
+            glist[lo].term, strlen(glist[lo].term),
             NULL, 0, zapt->term->which,rset_nmem,
             key_it_ctrl,key_it_ctrl->scope);
        
@@ -2985,8 +3003,8 @@ ZEBRA_RES rpn_scan(ZebraHandle zh, ODR stream, Z_AttributesPlusTerm *zapt,
                rsets[1] = rset_trunc(
                    zh,
                    &scan_info_array[j].list[before-1-ptr[j]].isam_p, 1,
-                   glist[before-1-i].term,
-                   strlen(glist[before-1-i].term), NULL, 0,
+                   glist[lo].term,
+                   strlen(glist[lo].term), NULL, 0,
                    zapt->term->which, rset_nmem,
                    key_it_ctrl, key_it_ctrl->scope);
                rset = rsmulti_or_create(rset_nmem, key_it_ctrl,
@@ -3004,7 +3022,7 @@ ZEBRA_RES rpn_scan(ZebraHandle zh, ODR stream, Z_AttributesPlusTerm *zapt,
            rset = rsmulti_and_create(rset_nmem, key_it_ctrl,
                                      key_it_ctrl->scope, 2, rsets);
        }
-       count_set (rset, &glist[before-1-i].occurrences);
+       count_set (rset, &glist[lo].occurrences);
        rset_delete (rset);
     }
     i = before-i;