Added the scope parameter to rsets, and using it in all forwards and reads
[idzebra-moved-to-github.git] / rset / rsbetween.c
index 1c9b8f7..63901cd 100644 (file)
@@ -1,4 +1,4 @@
-/* $Id: rsbetween.c,v 1.9 2003-06-12 18:14:49 adam Exp $
+/* $Id: rsbetween.c,v 1.25 2004-09-09 10:08:06 heikki Exp $
    Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002
    Index Data Aps
 
@@ -21,50 +21,55 @@ Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 */
 
 
+/* rsbetween is (mostly) used for xml searches. It returns the hits of the
+ * "middle" rset, that are in between the "left" and "right" rsets. For
+ * example "Shakespeare" in between "<title>" and </title>. The thing is 
+ * complicated by the inclusion of attributes (from their own rset). If attrs
+ * specified, they must match the "left" rset (start tag). "Hamlet" between
+ * "<title lang=eng>" and "</title>". (This assumes that the attributes are
+ * indexed to the same seqno as the tags).
+*/ 
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
 
-#include <rsbetween.h>
 #include <zebrautl.h>
+#include <rset.h>
+
+#define RSBETWEEN_DEBUG 0 
 
-static void *r_create_between(RSET ct, const struct rset_control *sel, void *parms);
 static RSFD r_open_between (RSET ct, int flag);
 static void r_close_between (RSFD rfd);
 static void r_delete_between (RSET ct);
 static void r_rewind_between (RSFD rfd);
-static int r_count_between (RSET ct);
-static int r_read_between (RSFD rfd, void *buf, int *term_index);
+static int r_forward_between(RSFD rfd, void *buf, const void *untilbuf);
+static int r_read_between (RSFD rfd, void *buf);
 static int r_write_between (RSFD rfd, const void *buf);
+static void r_pos_between (RSFD rfd, double *current, double *total);
 
-static const struct rset_control control_between = 
+static const struct rset_control control = 
 {
     "between",
-    r_create_between,
+    r_delete_between,
     r_open_between,
     r_close_between,
-    r_delete_between,
     r_rewind_between,
-    r_count_between,
+    r_forward_between, 
+    r_pos_between,
     r_read_between,
     r_write_between,
 };
 
 
-const struct rset_control *rset_kind_between = &control_between;
+const struct rset_control *rset_kind_between = &control;
 
 struct rset_between_info {
-    int key_size;
-    RSET rset_l;
-    RSET rset_m;
-    RSET rset_r;
-    RSET rset_attr;
-    int term_index_s;
-    int (*cmp)(const void *p1, const void *p2);
-    char *(*printer)(const void *p1, char *buf);
-    struct rset_between_rfd *rfd_list;
+    RSET rset_l;  /* left arg, start tag */
+    RSET rset_m;  /* the thing itself */
+    RSET rset_r;  /* right arg, end tag */
+    RSET rset_attr; /* attributes , optional */
 };
 
 struct rset_between_rfd {
@@ -76,236 +81,203 @@ struct rset_between_rfd {
     int  more_m;
     int  more_r;
     int  more_attr;
-    int term_index_l;
-    int term_index_m;
-    int term_index_r;
     void *buf_l;
     void *buf_m;
     void *buf_r;
     void *buf_attr;
-    int level;
-    struct rset_between_rfd *next;
-    struct rset_between_info *info;
+    int level;  /* counting start/end tags */
+    zint hits;
 };    
 
-static void *r_create_between (RSET ct, const struct rset_control *sel,
-                               void *parms)
+#if RSBETWEEN_DEBUG
+static void log2 (struct rset_between_rfd *p, char *msg, int cmp_l, int cmp_r)
 {
-    rset_between_parms *between_parms = (rset_between_parms *) parms;
-    struct rset_between_info *info;
-
-    info = (struct rset_between_info *) xmalloc (sizeof(*info));
-    info->key_size = between_parms->key_size;
-    info->rset_l = between_parms->rset_l;
-    info->rset_m = between_parms->rset_m;
-    info->rset_r = between_parms->rset_r;
-    info->rset_attr = between_parms->rset_attr;
-    if (rset_is_volatile(info->rset_l) || 
-        rset_is_volatile(info->rset_m) ||
-        rset_is_volatile(info->rset_r))
-        ct->flags |= RSET_FLAG_VOLATILE;
-    info->cmp = between_parms->cmp;
-    info->printer = between_parms->printer;
-    info->rfd_list = NULL;
-    
-    info->term_index_s = info->rset_l->no_rset_terms;
-    if (info->rset_m)
-    {
-        ct->no_rset_terms =
-            info->rset_l->no_rset_terms + 
-            info->rset_m->no_rset_terms + 
-            info->rset_r->no_rset_terms;
-        ct->rset_terms = (RSET_TERM *)
-            xmalloc (sizeof (*ct->rset_terms) * ct->no_rset_terms);
-        memcpy (ct->rset_terms, info->rset_l->rset_terms,
-                info->rset_l->no_rset_terms * sizeof(*ct->rset_terms));
-        memcpy (ct->rset_terms + info->rset_l->no_rset_terms,
-                info->rset_m->rset_terms,
-                info->rset_m->no_rset_terms * sizeof(*ct->rset_terms));
-        memcpy (ct->rset_terms + info->rset_l->no_rset_terms + 
-                info->rset_m->no_rset_terms,
-                info->rset_r->rset_terms,
-                info->rset_r->no_rset_terms * sizeof(*ct->rset_terms));
-    }
-    else
-    {
-        ct->no_rset_terms =
-            info->rset_l->no_rset_terms + 
-            info->rset_r->no_rset_terms;
-        ct->rset_terms = (RSET_TERM *)
-            xmalloc (sizeof (*ct->rset_terms) * ct->no_rset_terms);
-        memcpy (ct->rset_terms, info->rset_l->rset_terms,
-                info->rset_l->no_rset_terms * sizeof(*ct->rset_terms));
-        memcpy (ct->rset_terms + info->rset_l->no_rset_terms,
-                info->rset_r->rset_terms,
-                info->rset_r->no_rset_terms * sizeof(*ct->rset_terms));
-    }
+    char buf_l[32];
+    char buf_m[32];
+    char buf_r[32];
+    logf(LOG_DEBUG,"btw: %s l=%s(%d/%d) m=%s(%d) r=%s(%d/%d), lev=%d",
+      msg, 
+      (*p->info->printer)(p->buf_l, buf_l), p->more_l, cmp_l,
+      (*p->info->printer)(p->buf_m, buf_m), p->more_m,
+      (*p->info->printer)(p->buf_r, buf_r), p->more_r, cmp_r,
+      p->level);
+}
+#endif
 
-    return info;
+RSET rsbetween_create( NMEM nmem, const struct key_control *kcontrol,
+            int scope,
+            RSET rset_l, RSET rset_m, RSET rset_r, RSET rset_attr)
+{
+    RSET rnew=rset_create_base(&control, nmem, kcontrol, scope);
+    struct rset_between_info *info=
+        (struct rset_between_info *) nmem_malloc(rnew->nmem,sizeof(*info));
+    info->rset_l = rset_l;
+    info->rset_m = rset_m;
+    info->rset_r = rset_r;
+    info->rset_attr = rset_attr;
+    rnew->priv=info;
+    return rnew;
 }
 
+
+static void r_delete_between (RSET ct)
+{
+    struct rset_between_info *info = (struct rset_between_info *) ct->priv;
+
+    rset_delete (info->rset_l);
+    rset_delete (info->rset_m);
+    rset_delete (info->rset_r);
+    if (info->rset_attr)
+        rset_delete (info->rset_attr);
+}
+
+
 static RSFD r_open_between (RSET ct, int flag)
 {
-    struct rset_between_info *info = (struct rset_between_info *) ct->buf;
-    struct rset_between_rfd *rfd;
+    struct rset_between_info *info = (struct rset_between_info *) ct->priv;
+    RSFD rfd;
+    struct rset_between_rfd *p;
 
     if (flag & RSETF_WRITE)
     {
-       logf (LOG_FATAL, "between set type is read-only");
-       return NULL;
+        logf (LOG_FATAL, "between set type is read-only");
+        return NULL;
     }
-    rfd = (struct rset_between_rfd *) xmalloc (sizeof(*rfd));
-    rfd->next = info->rfd_list;
-    info->rfd_list = rfd;
-    rfd->info = info;
-
-    rfd->buf_l = xmalloc (info->key_size);
-    rfd->buf_m = xmalloc (info->key_size);
-    rfd->buf_r = xmalloc (info->key_size);
-    rfd->buf_attr = xmalloc (info->key_size);
-
-    rfd->rfd_l = rset_open (info->rset_l, RSETF_READ);
-    rfd->rfd_m = rset_open (info->rset_m, RSETF_READ);
-    rfd->rfd_r = rset_open (info->rset_r, RSETF_READ);
+    rfd=rfd_create_base(ct);
+    if (rfd->priv)  
+        p=(struct rset_between_rfd *)rfd->priv;
+    else {
+        p = (struct rset_between_rfd *) nmem_malloc(ct->nmem, (sizeof(*p)));
+        rfd->priv=p;
+        p->buf_l = nmem_malloc(ct->nmem, (ct->keycontrol->key_size));
+        p->buf_m = nmem_malloc(ct->nmem, (ct->keycontrol->key_size));
+        p->buf_r = nmem_malloc(ct->nmem, (ct->keycontrol->key_size));
+        p->buf_attr = nmem_malloc(ct->nmem, (ct->keycontrol->key_size));
+    }
+
+    p->rfd_l = rset_open (info->rset_l, RSETF_READ);
+    p->rfd_m = rset_open (info->rset_m, RSETF_READ);
+    p->rfd_r = rset_open (info->rset_r, RSETF_READ);
     
-    rfd->more_l = rset_read (info->rset_l, rfd->rfd_l, rfd->buf_l,
-                            &rfd->term_index_l);
-    rfd->more_m = rset_read (info->rset_m, rfd->rfd_m, rfd->buf_m,
-                            &rfd->term_index_m);
-    rfd->more_r = rset_read (info->rset_r, rfd->rfd_r, rfd->buf_r,
-                            &rfd->term_index_r);
+    p->more_l = rset_read (p->rfd_l, p->buf_l);
+    p->more_m = rset_read (p->rfd_m, p->buf_m);
+    p->more_r = rset_read (p->rfd_r, p->buf_r);
     if (info->rset_attr)
     {
-        int dummy;
-        rfd->rfd_attr = rset_open (info->rset_attr, RSETF_READ);
-        rfd->more_attr = rset_read (info->rset_attr, rfd->rfd_attr,
-                                    rfd->buf_attr, &dummy);
+        p->rfd_attr = rset_open (info->rset_attr, RSETF_READ);
+        p->more_attr = rset_read (p->rfd_attr, p->buf_attr);
     }
-    rfd->level=0;
+    p->level=0;
+    p->hits=0;
     return rfd;
 }
 
 static void r_close_between (RSFD rfd)
 {
-    struct rset_between_info *info = ((struct rset_between_rfd*)rfd)->info;
-    struct rset_between_rfd **rfdp;
-    
-    for (rfdp = &info->rfd_list; *rfdp; rfdp = &(*rfdp)->next)
-        if (*rfdp == rfd)
-        {
-            xfree ((*rfdp)->buf_l);
-            xfree ((*rfdp)->buf_m);
-            xfree ((*rfdp)->buf_r);
-            xfree ((*rfdp)->buf_attr);
-            rset_close (info->rset_l, (*rfdp)->rfd_l);
-            rset_close (info->rset_m, (*rfdp)->rfd_m);
-            rset_close (info->rset_r, (*rfdp)->rfd_r);
-            if (info->rset_attr)
-                rset_close (info->rset_attr, (*rfdp)->rfd_attr);
-            
-            *rfdp = (*rfdp)->next;
-            xfree (rfd);
-            return;
-        }
-    logf (LOG_FATAL, "r_close_between but no rfd match!");
-    assert (0);
-}
+    struct rset_between_info *info =(struct rset_between_info *)rfd->rset->priv;
+    struct rset_between_rfd *p=(struct rset_between_rfd *)rfd->priv;
 
-static void r_delete_between (RSET ct)
-{
-    struct rset_between_info *info = (struct rset_between_info *) ct->buf;
-
-    assert (info->rfd_list == NULL);
-    xfree (ct->rset_terms);
-    rset_delete (info->rset_l);
-    rset_delete (info->rset_m);
-    rset_delete (info->rset_r);
+    rset_close (p->rfd_l);
+    rset_close (p->rfd_m);
+    rset_close (p->rfd_r);
     if (info->rset_attr)
-        rset_delete (info->rset_attr);
-    xfree (info);
+        rset_close (p->rfd_attr);
+    rfd_delete_base(rfd);
 }
 
 static void r_rewind_between (RSFD rfd)
 {
-    struct rset_between_info *info = ((struct rset_between_rfd*)rfd)->info;
-    struct rset_between_rfd *p = (struct rset_between_rfd *) rfd;
+    struct rset_between_info *info =(struct rset_between_info *)rfd->rset->priv;
+    struct rset_between_rfd *p=(struct rset_between_rfd *)rfd->priv;
 
+#if RSBETWEEN_DEBUG
     logf (LOG_DEBUG, "rsbetween_rewind");
-    rset_rewind (info->rset_l, p->rfd_l);
-    rset_rewind (info->rset_m, p->rfd_m);
-    rset_rewind (info->rset_r, p->rfd_r);
-    p->more_l = rset_read (info->rset_l, p->rfd_l, p->buf_l, &p->term_index_l);
-    p->more_m = rset_read (info->rset_m, p->rfd_m, p->buf_m, &p->term_index_m);
-    p->more_r = rset_read (info->rset_r, p->rfd_r, p->buf_r, &p->term_index_r);
+#endif
+    rset_rewind (p->rfd_l);
+    rset_rewind (p->rfd_m);
+    rset_rewind (p->rfd_r);
+    p->more_l = rset_read (p->rfd_l, p->buf_l);
+    p->more_m = rset_read (p->rfd_m, p->buf_m);
+    p->more_r = rset_read (p->rfd_r, p->buf_r);
     if (info->rset_attr)
     {
-        int dummy;
-        rset_rewind (info->rset_attr, p->rfd_attr);
-        p->more_attr = rset_read (info->rset_attr, p->rfd_attr, p->buf_attr,
-                                  &dummy);
+        rset_rewind (p->rfd_attr);
+        p->more_attr = rset_read (p->rfd_attr, p->buf_attr);
     }
     p->level=0;
+    p->hits=0;
 }
 
-static int r_count_between (RSET ct)
-{
-    return 0;
-}
 
 
-static void log2 (struct rset_between_rfd *p, char *msg, int cmp_l, int cmp_r)
+static int r_forward_between(RSFD rfd, void *buf, const void *untilbuf)
 {
-    char buf_l[32];
-    char buf_m[32];
-    char buf_r[32];
-    logf(LOG_DEBUG,"btw: %s l=%s(%d/%d) m=%s(%d) r=%s(%d/%d), lev=%d",
-      msg, 
-      (*p->info->printer)(p->buf_l, buf_l), p->more_l, cmp_l,
-      (*p->info->printer)(p->buf_m, buf_m), p->more_m,
-      (*p->info->printer)(p->buf_r, buf_r), p->more_r, cmp_r,
-      p->level);
+    struct rset_between_rfd *p=(struct rset_between_rfd *)rfd->priv;
+    int rc;
+#if RSBETWEEN_DEBUG
+    log2( p, "fwd: before forward", 0,0);
+#endif
+    /* It is enough to forward the m pointer here, the read will */
+    /* naturally forward the l, m, and attr pointers */
+    if (p->more_m)
+        p->more_m=rset_forward(p->rfd_m, p->buf_m,untilbuf);
+#if RSBETWEEN_DEBUG
+    log2( p, "fwd: after forward M", 0,0);
+#endif
+    rc = r_read_between(rfd, buf);
+#if RSBETWEEN_DEBUG
+    log2( p, "fwd: after forward", 0,0);
+#endif
+    return rc;
 }
 
-static int r_read_between (RSFD rfd, void *buf, int *term_index)
+
+
+
+static int r_read_between (RSFD rfd, void *buf)
 {
-    struct rset_between_rfd *p = (struct rset_between_rfd *) rfd;
-    struct rset_between_info *info = p->info;
+    struct rset_between_info *info =(struct rset_between_info *)rfd->rset->priv;
+    struct rset_between_rfd *p=(struct rset_between_rfd *)rfd->priv;
+    const struct key_control *kctrl=rfd->rset->keycontrol;
     int cmp_l=0;
     int cmp_r=0;
     int attr_match = 0;
 
     while (p->more_m)
     {
+#if RSBETWEEN_DEBUG
         log2( p, "start of loop", cmp_l, cmp_r);
+#endif
 
-       /* forward L until past m, count levels, note rec boundaries */
-       if (p->more_l)
-           cmp_l= (*info->cmp)(p->buf_l, p->buf_m);
-       else
-       {
-           p->level = 0;
-           cmp_l=2; /* past this record */
-       }
+        /* forward L until past m, count levels, note rec boundaries */
+        if (p->more_l)
+            cmp_l= (*kctrl->cmp)(p->buf_l, p->buf_m);
+        else
+        {
+            p->level = 0;
+            cmp_l=rfd->rset->scope; /* past this record */
+        }
+#if RSBETWEEN_DEBUG
         log2( p, "after first L", cmp_l, cmp_r);
+#endif
 
         while (cmp_l < 0)   /* l before m */
-       {
-            if (cmp_l == -2)
-               p->level=0; /* earlier record */
-            if (cmp_l == -1)
+        {
+            if (cmp_l <= - rfd->rset->scope)  /* ==-2 */
+                p->level=0; /* earlier record */
+            if (cmp_l > - rfd->rset->scope)  /* == -1 */
             {
-               p->level++; /* relevant start tag */
+                p->level++; /* relevant start tag */
 
                 if (!info->rset_attr)
                     attr_match = 1;
                 else
                 {
                     int cmp_attr;
-                    int dummy_term;
                     attr_match = 0;
                     while (p->more_attr)
                     {
-                        cmp_attr = (*info->cmp)(p->buf_attr, p->buf_l);
+                        cmp_attr = (*kctrl->cmp)(p->buf_attr, p->buf_l);
                         if (cmp_attr == 0)
                         {
                             attr_match = 1;
@@ -313,73 +285,142 @@ static int r_read_between (RSFD rfd, void *buf, int *term_index)
                         }
                         else if (cmp_attr > 0)
                             break;
-                        p->more_attr = rset_read (info->rset_attr, p->rfd_attr,
-                                                  p->buf_attr, &dummy_term);
-                    }
+                        else if (cmp_attr > - rfd->rset->scope)  /* == -1 */
+                            p->more_attr = rset_read (p->rfd_attr, p->buf_attr);
+                            /* if we had a forward that went all the way to
+                             * the seqno, we could use that. But fwd only goes
+                             * to the sysno */
+                        else if (cmp_attr <= - rfd->rset->scope) /* ==-2 */
+                        {
+                            p->more_attr = rset_forward( p->rfd_attr,
+                                             p->buf_attr, p->buf_l);
+#if RSBETWEEN_DEBUG
+                            logf(LOG_DEBUG, "btw: after frowarding attr m=%d",
+                                      p->more_attr);
+#endif
+                        }
+                    } /* while more_attr */
                 }
             }
-            p->more_l = rset_read (info->rset_l, p->rfd_l, p->buf_l,
-                          &p->term_index_l);
+#define NEWCODE 1 
+#if NEWCODE                
+            if (cmp_l <= - rfd->rset->scope )/* ==-2 */
+            {
+                if (p->more_l) 
+                {
+                    p->more_l=rset_forward(p->rfd_l, p->buf_l, p->buf_m);
+                    if (p->more_l)
+                        cmp_l= (*kctrl->cmp)(p->buf_l, p->buf_m);
+                    else
+                        cmp_l=rfd->rset->scope;  /*2*/
+#if RSBETWEEN_DEBUG
+                    log2( p, "after forwarding L", cmp_l, cmp_r);
+#endif
+                }
+            } else
+            {
+                p->more_l = rset_read (p->rfd_l, p->buf_l);
+            }
+#else
+            p->more_l = rset_read (p->rfd_l, p->buf_l);
+#endif
             if (p->more_l)
             {
-               cmp_l= (*info->cmp)(p->buf_l, p->buf_m);
+                cmp_l= (*kctrl->cmp)(p->buf_l, p->buf_m);
             }
             else
-               cmp_l=2; 
-           log2( p, "end of L loop", cmp_l, cmp_r);
+                cmp_l=rfd->rset->scope;   /*2*/
+#if RSBETWEEN_DEBUG
+            log2( p, "end of L loop", cmp_l, cmp_r);
+#endif
         } /* forward L */
 
             
-       /* forward R until past m, count levels */
+        /* forward R until past m, count levels */
+#if RSBETWEEN_DEBUG
         log2( p, "Before moving R", cmp_l, cmp_r);
+#endif
         if (p->more_r)
-           cmp_r= (*info->cmp)(p->buf_r, p->buf_m);
-       else
-           cmp_r=2; 
+            cmp_r= (*kctrl->cmp)(p->buf_r, p->buf_m);
+        else
+            cmp_r=rfd->rset->scope;  /*2*/
+#if RSBETWEEN_DEBUG
         log2( p, "after first R", cmp_l, cmp_r);
+#endif
         while (cmp_r < 0)   /* r before m */
-       {
-           /* -2, earlier record, doesn't matter */
-            if (cmp_r == -1)
-               p->level--; /* relevant end tag */
+        {
+             /* -2, earlier record, don't count level */
+            if (cmp_r > -rfd->rset->scope) /* == -1 */
+                p->level--; /* relevant end tag */
             if (p->more_r)
             {
-                p->more_r = rset_read (info->rset_r, p->rfd_r, p->buf_r,
-                                  &p->term_index_r);
-               cmp_r= (*info->cmp)(p->buf_r, p->buf_m);
+#if NEWCODE                
+                if (cmp_r <= - rfd->rset->scope) /* == -2 */
+                {
+                    p->more_r=rset_forward(p->rfd_r, p->buf_r, p->buf_m);
+                } else
+                {
+                    p->more_r = rset_read (p->rfd_r, p->buf_r);
+                }
+                if (p->more_r)
+                    cmp_r= (*kctrl->cmp)(p->buf_r, p->buf_m);
+
+#else
+                p->more_r = rset_read (p->rfd_r, p->buf_r);
+                cmp_r= (*kctrl->cmp)(p->buf_r, p->buf_m);
+#endif
             }
             else
-               cmp_r=2; 
+                cmp_r=rfd->rset->scope;  /*2*/
+#if RSBETWEEN_DEBUG
         log2( p, "End of R loop", cmp_l, cmp_r);
+#endif
         } /* forward R */
-       
-       if ( ( p->level <= 0 ) && ! p->more_l)
-           return 0; /* no more start tags, nothing more to find */
         
-       if ( attr_match && p->level > 0)  /* within a tag pair (or deeper) */
-       {
-           memcpy (buf, p->buf_m, info->key_size);
-            *term_index = p->term_index_m;
+        if ( ( p->level <= 0 ) && ! p->more_l)
+            return 0; /* no more start tags, nothing more to find */
+        
+        if ( attr_match && p->level > 0)  /* within a tag pair (or deeper) */
+        {
+            memcpy (buf, p->buf_m, kctrl->key_size);
+#if RSBETWEEN_DEBUG
             log2( p, "Returning a hit (and forwarding m)", cmp_l, cmp_r);
-            p->more_m = rset_read (info->rset_m, p->rfd_m, p->buf_m,
-                                   &p->term_index_m);
-           if (cmp_l == 2)
-               p->level = 0;
-           return 1;
-       }
-       else if ( ! p->more_l )  /* not in data, no more starts */
-       {
-           log2( p, "no more starts, exiting without a hit", cmp_l, cmp_r);
-           return 0;  /* ergo, nothing can be found. stop scanning */
-       }
-       if (cmp_l == 2)
-           p->level = 0;
-        p->more_m = rset_read (info->rset_m, p->rfd_m, p->buf_m,
-                               &p->term_index_m);
+#endif
+            p->more_m = rset_read (p->rfd_m, p->buf_m);
+            if (cmp_l >= rfd->rset->scope)  /* == 2 */
+                p->level = 0;
+            p->hits++;
+            return 1;
+        }
+        else if ( ! p->more_l )  /* not in data, no more starts */
+        {
+#if RSBETWEEN_DEBUG
+            log2( p, "no more starts, exiting without a hit", cmp_l, cmp_r);
+#endif
+            return 0;  /* ergo, nothing can be found. stop scanning */
+        }
+#if NEWCODE                
+        if (cmp_l >= rfd->rset->scope) /* == 2 */
+        {
+            p->level = 0;
+            p->more_m=rset_forward(p->rfd_m, p->buf_m,  p->buf_l);
+        } else
+        {
+            p->more_m = rset_read (p->rfd_m, p->buf_m);
+        }
+#else
+        if (cmp_l >= rfd->rset->scope )  /* == 2 */
+            p->level = 0;
+        p->more_m = rset_read (p->rfd_m, p->buf_m);
+#endif
+#if RSBETWEEN_DEBUG
         log2( p, "End of M loop", cmp_l, cmp_r);
+#endif
     } /* while more_m */
     
+#if RSBETWEEN_DEBUG
     log2( p, "Exiting, nothing more in m", cmp_l, cmp_r);
+#endif
     return 0;  /* no more data possible */
 
 
@@ -392,3 +433,36 @@ static int r_write_between (RSFD rfd, const void *buf)
     return -1;
 }
 
+
+static void r_pos_between (RSFD rfd, double *current, double *total)
+{
+    struct rset_between_rfd *p=(struct rset_between_rfd *)rfd->priv;
+    double lcur,ltot;
+    double mcur,mtot;
+    double rcur,rtot;
+    double r;
+    ltot=-1; rtot=-1;
+    rset_pos(p->rfd_l,  &lcur, &ltot);
+    rset_pos(p->rfd_m,  &mcur, &mtot);
+    rset_pos(p->rfd_r,  &rcur, &rtot);
+    if ( (ltot<0) && (mtot<0) && (rtot<0) ) { /*no position */
+        *current=mcur;  /* return same as you got */
+        *total=mtot;    /* probably -1 for not available */
+    }
+    if ( ltot<0) { ltot=0; lcur=0;} /* if only one useful, use it */
+    if ( mtot<0) { mtot=0; mcur=0;}
+    if ( rtot<0) { rtot=0; rcur=0;}
+    if ( ltot+mtot+rtot < 1 ) { /* empty rset */
+        *current=0;
+        *total=0;
+        return;
+    }
+    r=1.0*(lcur+mcur+rcur)/(ltot+mtot+rtot); /* weighed average of l and r */
+    *current=p->hits;
+    *total=*current/r ; 
+#if RSBETWEEN_DEBUG
+    yaz_log(LOG_DEBUG,"betw_pos: (%s/%s) %0.1f/%0.1f= %0.4f ",
+                    info->rset_l->control->desc, info->rset_r->control->desc,
+                    *current, *total, r);
+#endif
+}