X-Git-Url: http://git.indexdata.com/?p=yaz-moved-to-github.git;a=blobdiff_plain;f=src%2Fnfa.c;h=fe6362ea7f4841235151b441c2fe239b009a099b;hp=ef6f3f41c43319550f0046969b39f0a0fabd6b3e;hb=e4368af2ede9079d33e7a8fd280d29b2bde1d1ad;hpb=b77f4b5c2b191b83cf3f213faa8b6b263e36fea4

diff --git a/src/nfa.c b/src/nfa.c
index ef6f3f4..fe6362e 100644
--- a/src/nfa.c
+++ b/src/nfa.c
@@ -1,7 +1,12 @@
 /*  Copyright (C) 2006, Index Data ApS
  *  See the file LICENSE for details.
  * 
- *  $Id: nfa.c,v 1.4 2006-05-03 13:47:35 heikki Exp $ 
+ *  $Id: nfa.c,v 1.12 2006-07-14 13:06:38 heikki Exp $ 
+ */
+
+/**
+ * \file nfa.c
+ * \brief NFA for character set normalizing
  *
  *  This is a simple NFA-based system for character set normalizing
  *  in yaz and zebra. Unlike standard NFA's, this operates on ranges of
@@ -18,7 +23,9 @@
  *  strings with it.
  */
 
+
 #include <stdio.h>
+#include <string.h>
 #include <yaz/nfa.h>
 #include <yaz/nmem.h> 
 
@@ -70,6 +77,21 @@ struct yaz_nfa_transition {
 #define LOOP_LIMIT 100
 
 
+typedef enum {
+    conv_none,
+    conv_string,
+    conv_backref,
+    conv_range
+} yaz_nfa_converter_type;
+
+struct yaz_nfa_converter {
+    yaz_nfa_converter *next;
+    yaz_nfa_converter_type type;
+    yaz_nfa_char *string;
+    size_t strlen;
+    int backref_no;
+    int char_diff;
+};
 
 
 /* * * * * * *
@@ -78,20 +100,21 @@ struct yaz_nfa_transition {
 
 yaz_nfa *yaz_nfa_init() {
     NMEM my_nmem = nmem_create();
-    yaz_nfa *n=nmem_malloc(my_nmem, sizeof(yaz_nfa));
-    n->nmem=my_nmem;
-    n->nstates=0;
-    n->laststate=0;
-    n->firststate=0;
-    n->nbackrefs=0;
-    n->curr_backrefs=0;
-    n->best_backrefs=0;
-    n->lastmatch= YAZ_NFA_NOMATCH;
+    yaz_nfa *n = nmem_malloc(my_nmem, sizeof(yaz_nfa));
+    n->nmem = my_nmem;
+    n->nbackrefs = 1;  /* we always have #0, last range match */
+    n->curr_backrefs = 0;
+    n->best_backrefs = 0;
+    n->lastmatch = YAZ_NFA_NOMATCH;
+    n->nstates = 0;
+    n->laststate = 0;
+    n->firststate = n->laststate ;
     return n;
 }
 
 void yaz_nfa_destroy(yaz_nfa *n) {
-    nmem_destroy(n->nmem);
+    if (n && n->nmem)
+        nmem_destroy(n->nmem);
 }
 
 
@@ -100,28 +123,28 @@ void yaz_nfa_destroy(yaz_nfa *n) {
  * * * * * */
 
 yaz_nfa_state *yaz_nfa_add_state(yaz_nfa *n) {
-    yaz_nfa_state *s = nmem_malloc(n->nmem,sizeof(yaz_nfa_state));
+    yaz_nfa_state *s = nmem_malloc(n->nmem, sizeof(yaz_nfa_state));
     s->num = (n->nstates)++;
-    s->result=0;
-    s->lasttrans=0;
-    s->backref_start=0;
-    s->backref_end=0;
+    s->result = 0;
+    s->lasttrans = 0;
+    s->backref_start = 0;
+    s->backref_end = 0;
     if (n->laststate) { 
-        s->next=n->laststate->next;
-        n->laststate->next=s;
-        n->laststate=s;
+        s->next = n->laststate->next;
+        n->laststate->next = s;
+        n->laststate = s;
     } else { /* first state */
-        n->laststate=s;
-        n->firststate=s;
-        s->next=s;
+        n->laststate = s;
+        n->firststate = s;
+        s->next = s;
     }
     return s;
 }
 
-int yaz_nfa_set_result(yaz_nfa *n, yaz_nfa_state *s,void *result) {
+int yaz_nfa_set_result(yaz_nfa *n, yaz_nfa_state *s, void *result) {
     if ((s->result)&&result)
-        return 1;
-    s->result=result;
+        return YAZ_NFA_ALREADY;
+    s->result = result;
     return 0;
 }
 
@@ -136,22 +159,22 @@ int yaz_nfa_set_backref_point(yaz_nfa *n, yaz_nfa_state *s,
            int is_start ){
     if (is_start) {
         if (s->backref_start)
-            return 1;
-        s->backref_start=backref_number;
+            return YAZ_NFA_ALREADY;
+        s->backref_start = backref_number;
         if (n->nbackrefs<=backref_number) {
-            n->nbackrefs=backref_number+1;
-            n->curr_backrefs=0;
-            n->best_backrefs=0;
+            n->nbackrefs = backref_number+1;
+            n->curr_backrefs = 0;
+            n->best_backrefs = 0;
             /* clear them just in case we have already matched on */
             /* with this nfa, and created a too small backref table */
             /* we will reallocate when matching. */
         }
     } else {
         if (s->backref_end)
-            return 1;
-        if (n->nbackrefs<backref_number) 
-            return 2; /* can't end a backref that has not been started */
-        s->backref_end=backref_number;
+            return YAZ_NFA_ALREADY;
+        if (n->nbackrefs<=backref_number) 
+            return YAZ_NFA_NOSTART; 
+        s->backref_end = backref_number;
     }
     return 0; /* ok */
 }
@@ -171,25 +194,27 @@ void yaz_nfa_add_transition(yaz_nfa *n,
         yaz_nfa_state *to_state,
         yaz_nfa_char range_start, 
         yaz_nfa_char range_end) {
-    yaz_nfa_transition *t=nmem_malloc(n->nmem,sizeof(yaz_nfa_transition));
-    t->range_start=range_start;
-    t->range_end=range_end;
-    t->to_state=to_state;
+    yaz_nfa_transition *t = nmem_malloc(n->nmem, sizeof(yaz_nfa_transition));
+    if (!from_state)
+        from_state = n->firststate;
+    t->range_start = range_start;
+    t->range_end = range_end;
+    t->to_state = to_state;
     if (from_state->lasttrans) {
         t->next= from_state->lasttrans->next;
-        from_state->lasttrans->next=t;
-        from_state->lasttrans=t;
+        from_state->lasttrans->next = t;
+        from_state->lasttrans = t;
     } else { /* first trans */
-        from_state->lasttrans=t;
-        t->next=t;
+        from_state->lasttrans = t;
+        t->next = t;
     }
 }
 
 void yaz_nfa_add_empty_transition( yaz_nfa *n,
         yaz_nfa_state *from_state,
         yaz_nfa_state *to_state) {
-    yaz_nfa_add_transition(n,from_state,to_state,
-              EMPTY_START,EMPTY_END);
+    yaz_nfa_add_transition(n, from_state, to_state,
+              EMPTY_START, EMPTY_END);
 }
 
 /* * * * * * * *
@@ -202,11 +227,11 @@ static yaz_nfa_state *find_single_trans(
           yaz_nfa_state *s, 
           yaz_nfa_char range_start,
           yaz_nfa_char range_end) {
-    yaz_nfa_transition *t=s->lasttrans;
+    yaz_nfa_transition *t = s->lasttrans;
     if (!t)
         return 0;
     do {
-        t=t->next;
+        t = t->next;
         if ( ( t->range_start == range_start ) && ( t->range_end == range_end) )
             return t->to_state;
     } while (t != s->lasttrans );
@@ -218,10 +243,13 @@ yaz_nfa_state *yaz_nfa_add_range(yaz_nfa *n,
         yaz_nfa_state *s,
         yaz_nfa_char range_start, 
         yaz_nfa_char range_end) {
-    yaz_nfa_state *nextstate;
+    yaz_nfa_state *nextstate=0;
     if (!s) /* default to top-level of the nfa */
-        s=n->firststate;
-    nextstate=find_single_trans(s,range_start,range_end);
+        s = n->firststate;
+    if (s)
+        nextstate = find_single_trans(s, range_start, range_end);
+    else
+        s = yaz_nfa_add_state(n); /* create initial state */
     if (!nextstate) {
         nextstate = yaz_nfa_add_state(n);
         yaz_nfa_add_transition(n, s, nextstate, range_start, range_end);
@@ -231,21 +259,25 @@ yaz_nfa_state *yaz_nfa_add_range(yaz_nfa *n,
 
 yaz_nfa_state *yaz_nfa_add_sequence(yaz_nfa *n, 
         yaz_nfa_state *s, 
-        yaz_nfa_char *seq ){
-    yaz_nfa_state *nextstate;
+        yaz_nfa_char *seq,
+        size_t seq_len){
+    yaz_nfa_state *nextstate=0;
     if (!s) /* default to top-level of the nfa */
-        s=n->firststate;
-    nextstate=find_single_trans(s,*seq,*seq);
+        s = n->firststate;
+    if (s) 
+        nextstate = find_single_trans(s, *seq, *seq);
     if (nextstate) {
         seq++;
-        if (!*seq) /* whole sequence matched */
+        seq_len--;
+        if (!seq_len) /* whole sequence matched */
             return nextstate;
         else
-            return yaz_nfa_add_sequence(n, nextstate, seq);
+            return yaz_nfa_add_sequence(n, nextstate, seq,seq_len);
     } else { /* no next state, build the rest */
-        while (*seq) {
-            s=yaz_nfa_add_range(n,s, *seq, *seq);
+        while (seq_len) {
+            s = yaz_nfa_add_range(n, s, *seq, *seq);
             seq++;
+            seq_len--;
         }
         return s;
     }
@@ -261,7 +293,7 @@ yaz_nfa_state *yaz_nfa_add_sequence(yaz_nfa *n,
 struct matcher {
     yaz_nfa *n; 
     yaz_nfa_char *longest;
-    int bestnode;
+    int bestnode; 
     void *result;
     int errorcode;
     int empties; /* count how many consecutive empty transitions */
@@ -273,37 +305,40 @@ struct matcher {
 
 static void match_state(
               yaz_nfa_state *s, 
-              yaz_nfa_char *inchar,
-              size_t incharsleft,
-              struct matcher *m ) {
-    yaz_nfa_transition *t=s->lasttrans;
+              yaz_nfa_char *prevmatch,
+              yaz_nfa_char *inchar,   
+              size_t incharsleft,    
+              struct matcher *m ) {   
+    yaz_nfa_transition *t = s->lasttrans;
     if (s->backref_start) 
-        m->n->curr_backrefs[s->backref_start].start=inchar;
+        m->n->curr_backrefs[s->backref_start].start = inchar;
     if (s->backref_end) 
-        m->n->curr_backrefs[s->backref_end].end=inchar;
+        m->n->curr_backrefs[s->backref_end].end = prevmatch;
     if (t) {
         if (incharsleft) {
             do {
-                t=t->next;
-                if ( (( t->range_start <= *inchar ) && ( t->range_end >= *inchar )) ){
-                    m->empties=0;
+                t = t->next;
+                if ( (( t->range_start <= *inchar ) && 
+                      ( t->range_end >= *inchar )) ){
+                    m->empties = 0;
                     if (t->range_start!=t->range_end){
                         /* backref 0 is special: the last range operation */
-                        m->n->curr_backrefs[0].start=inchar;
-                        m->n->curr_backrefs[0].end=inchar;
+                        m->n->curr_backrefs[0].start = inchar;
+                        m->n->curr_backrefs[0].end = inchar;
                     }
-                    match_state(t->to_state, inchar+1,incharsleft-1,m);
-                    /* yes, descent to all matching nodes, even if overrun, */
-                    /* since we can find a better one later */
-                } else if (( t->range_start==EMPTY_START) && (t->range_end==EMPTY_END)) {
+                    match_state(t->to_state, inchar, 
+                            inchar+1, incharsleft-1, m);
+                } else if (( t->range_start==EMPTY_START) && 
+                           (t->range_end==EMPTY_END)) {
                     if ( m->empties++ > LOOP_LIMIT ) 
                         m->errorcode= YAZ_NFA_LOOP;
                     else
-                        match_state(t->to_state, inchar,incharsleft,m);
+                        match_state(t->to_state, prevmatch, 
+                                inchar, incharsleft, m);
                 }
             } while (t != s->lasttrans );
         } else {
-            m->errorcode=YAZ_NFA_OVERRUN;
+            m->errorcode = YAZ_NFA_OVERRUN;
         }
     }
     if (s->result) { /* terminal node */
@@ -311,63 +346,64 @@ static void match_state(
              ((m->longest == inchar)&&(m->bestnode<s->num)) ){
               /* or as long, but with lower node number. Still better */
            int i;
-           m->longest=inchar;
-           m->bestnode=s->num;
-           m->result=s->result;
+           m->longest = inchar;
+           m->bestnode = s->num;
+           m->result = s->result;
            if (m->n->curr_backrefs) 
-               for (i=0; i<m->n->nbackrefs;i++)  {
+               for (i = 0; i<m->n->nbackrefs; i++)  {
                    m->n->best_backrefs[i]=m->n->curr_backrefs[i];
                }
         }
     }
     if (s->backref_start) 
-        m->n->curr_backrefs[s->backref_start].start=0;
+        m->n->curr_backrefs[s->backref_start].start = 0;
     if (s->backref_end) 
-        m->n->curr_backrefs[s->backref_end].end=0;
-    m->n->curr_backrefs[0].start=0;
-    m->n->curr_backrefs[0].end=0;
+        m->n->curr_backrefs[s->backref_end].end = 0;
+    m->n->curr_backrefs[0].start = 0;
+    m->n->curr_backrefs[0].end = 0;
 } /* match_state */
 
 int yaz_nfa_match(yaz_nfa *n, 
            yaz_nfa_char **inbuff, 
-           size_t incharsleft,
+           size_t *incharsleft,
            void **result ){
     struct matcher m;
     int sz;
     int i;
     if (!n->firststate) {
-        n->lastmatch=YAZ_NFA_NOMATCH;
+        n->lastmatch = YAZ_NFA_NOMATCH;
         return n->lastmatch;
     }
-    m.n=n;
+    m.n = n;
     m.longest=*inbuff;
-    m.bestnode=n->nstates;
-    m.result=0;
-    m.errorcode=0;
-    sz=sizeof( struct yaz_nfa_backref_info) * n->nbackrefs;
+    m.bestnode = n->nstates;
+    m.result = 0;
+    m.errorcode = YAZ_NFA_SUCCESS;
+    m.empties = 0;
+    sz = sizeof( struct yaz_nfa_backref_info) * n->nbackrefs;
     if (!n->curr_backrefs) {
-        n->curr_backrefs=nmem_malloc( n->nmem, sz);
-        n->best_backrefs=nmem_malloc( n->nmem, sz);
+        n->curr_backrefs = nmem_malloc( n->nmem, sz);
+        n->best_backrefs = nmem_malloc( n->nmem, sz);
     }
-    for (i=0;i<n->nbackrefs;i++) {
-        n->curr_backrefs[i].start=0;
-        n->curr_backrefs[i].end=0;
-        n->best_backrefs[i].start=0;
-        n->best_backrefs[i].end=0;
+    for (i = 0; i<n->nbackrefs; i++) {
+        n->curr_backrefs[i].start = 0;
+        n->curr_backrefs[i].end = 0;
+        n->best_backrefs[i].start = 0;
+        n->best_backrefs[i].end = 0;
     }
 
-    match_state(n->firststate, *inbuff, incharsleft, &m);
-    if (m.result) {
-        *result=m.result;
-        *inbuff=m.longest;
-        if (m.errorcode)
-            n->lastmatch=m.errorcode;
-        else
-            n->lastmatch= YAZ_NFA_SUCCESS;
-        return n->lastmatch;
+    match_state(n->firststate, *inbuff, *inbuff, *incharsleft, &m);
+    if (m.errorcode==YAZ_NFA_SUCCESS) {
+        if (!m.result)
+            m.errorcode=YAZ_NFA_NOMATCH;
+        else {
+            *incharsleft -= (m.longest-*inbuff);
+            *result = m.result;
+            *inbuff = m.longest;
+        }
     }
-    n->lastmatch=YAZ_NFA_NOMATCH;
-    return n->lastmatch; 
+    n->lastmatch=m.errorcode;
+    return m.errorcode;
 }
 
 
@@ -375,18 +411,254 @@ int yaz_nfa_get_backref( yaz_nfa *n,
                 int backref_no,
                 yaz_nfa_char **start,
                 yaz_nfa_char **end) {
-    if (backref_no>=n->nbackrefs)
-        return 2;
-    if (backref_no<0)
-        return 2;
-    if (n->lastmatch== YAZ_NFA_NOMATCH)
-        return 1;  /* accept other errors, they return partial matches*/
-
-    *start=n->best_backrefs[backref_no].start;
-    *end=n->best_backrefs[backref_no].end;
+    if (backref_no >= n->nbackrefs)
+        return YAZ_NFA_NOSUCHBACKREF;
+    if (backref_no < 0)
+        return YAZ_NFA_NOSUCHBACKREF;
+    if (n->lastmatch != YAZ_NFA_SUCCESS)
+        return YAZ_NFA_NOMATCH;  
+
+    *start = n->best_backrefs[backref_no].start;
+    *end = n->best_backrefs[backref_no].end;
     return 0;
 }
 
+/* * * * * * * * * * * * * *
+ * Converters 
+ * * * * * * * * * * * * * */
+
+static yaz_nfa_converter *create_null_converter ( yaz_nfa *n) {
+    yaz_nfa_converter *c;
+    c=nmem_malloc(n->nmem, sizeof(yaz_nfa_converter));
+    c->next=0;
+    c->type=conv_none;
+    c->string=0;
+    c->strlen=0;
+    c->backref_no=0;
+    c->char_diff=0;
+    return c;
+}
+
+yaz_nfa_converter *yaz_nfa_create_string_converter (
+                yaz_nfa *n,
+                yaz_nfa_char *string,
+                size_t length){
+    yaz_nfa_converter *c;
+    size_t i;
+    c=create_null_converter(n);
+    c->type=conv_string;
+    c->string=nmem_malloc(n->nmem, length*sizeof(yaz_nfa_char));
+    for (i=0;i<length;i++)
+        c->string[i]=string[i];
+    c->strlen=length;
+    return c;
+}
+
+yaz_nfa_converter *yaz_nfa_create_backref_converter (
+                   yaz_nfa *n, int backref_no ) {
+    yaz_nfa_converter *c;
+    c=create_null_converter(n);
+    c->type=conv_backref;
+    c->backref_no=backref_no;
+    return c;
+}
+
+yaz_nfa_converter *yaz_nfa_create_range_converter (
+                yaz_nfa *n, int backref_no,
+                yaz_nfa_char from_char,
+                yaz_nfa_char to_char){
+    yaz_nfa_converter *c;
+    c=create_null_converter(n);
+    c->type=conv_range;
+    c->backref_no=backref_no;
+    c->char_diff=to_char - from_char;
+    return c;
+    
+}
+
+
+void yaz_nfa_append_converter (
+                yaz_nfa *n,
+                yaz_nfa_converter *startpoint,
+                yaz_nfa_converter *newconverter) {
+    while (startpoint->next)
+        startpoint=startpoint->next;
+    startpoint->next=newconverter;
+}
+
+static int string_convert (
+                yaz_nfa *n,
+                yaz_nfa_converter *c,
+                yaz_nfa_char **outbuff,
+                size_t *outcharsleft){
+    size_t sz=c->strlen;
+    yaz_nfa_char *p=c->string;
+    while (sz--) {
+        if ((*outcharsleft)-- <= 0)
+            return YAZ_NFA_NOSPACE;
+        **outbuff=*p++;
+        (*outbuff)++;
+    }
+    return YAZ_NFA_SUCCESS;
+}
+static int backref_convert (
+                yaz_nfa *n,
+                yaz_nfa_converter *c,
+                yaz_nfa_char **outbuff,
+                size_t *outcharsleft){
+    yaz_nfa_char *cp1,*cp2;
+    int i;
+    i = yaz_nfa_get_backref(n,c->backref_no, &cp1, &cp2);
+    if ( i == YAZ_NFA_NOSUCHBACKREF) /* no backref, produce no output */
+        return YAZ_NFA_SUCCESS; 
+    if ( i == YAZ_NFA_NOMATCH ) /* no match in dfa */
+        return 1; /* should not happen */
+    while (cp2 >= cp1) {
+        if ((*outcharsleft)-- <= 0)
+            return YAZ_NFA_NOSPACE;
+        **outbuff=*cp1++;
+        (*outbuff)++;
+    }
+    return YAZ_NFA_SUCCESS;
+}
+
+static int range_convert (
+                yaz_nfa *n,
+                yaz_nfa_converter *c,
+                yaz_nfa_char **outbuff,
+                size_t *outcharsleft){
+    yaz_nfa_char *cp1=0, *cp2=0;
+    int i;
+    i = yaz_nfa_get_backref(n,c->backref_no, &cp1, &cp2);
+    if (i == YAZ_NFA_NOSUCHBACKREF) /* no backref, produce no output, not ok */
+        return YAZ_NFA_NOSUCHBACKREF; /* should not happen */
+    if (i == YAZ_NFA_NOMATCH) /* no match in dfa */
+        return YAZ_NFA_NOMATCH; /* should not happen */
+    while (cp2 >= cp1) {
+        if ((*outcharsleft)-- <= 0)
+            return YAZ_NFA_NOSPACE;
+        **outbuff=(*cp1++) + c->char_diff ;
+        (*outbuff)++;
+    }
+    return YAZ_NFA_SUCCESS;
+}
+
+
+int yaz_nfa_run_converters(
+                yaz_nfa *n,
+                yaz_nfa_converter *c,
+                yaz_nfa_char **outbuff,
+                size_t *outcharsleft){
+    int rc=0;
+    while (c && !rc) {
+        switch(c->type) {
+            case conv_string:
+                rc=string_convert(n,c,outbuff,outcharsleft);
+                break;
+            case conv_backref:
+                rc=backref_convert(n,c,outbuff,outcharsleft);
+                break;
+            case conv_range:
+                rc=range_convert(n,c,outbuff,outcharsleft);
+                break;
+            default:
+                rc=YAZ_NFA_INTERNAL; /* should never happen */
+        }
+        c=c->next;
+    }
+    return rc;
+}
+
+/* * * * * * * *
+ * High-level interface
+ * These routines build the nfa and add converters, all 
+ * in one go.
+ * * * * * * * */
+
+int yaz_nfa_add_string_rule( yaz_nfa *n,
+        yaz_nfa_char *from_string,
+        size_t        from_length,
+        yaz_nfa_char *to_string,
+        size_t        to_length ) {
+    yaz_nfa_state *s= 
+        yaz_nfa_add_sequence(n, 0, from_string,from_length);
+    yaz_nfa_converter *c=
+        yaz_nfa_create_string_converter(n,to_string,to_length);
+    return yaz_nfa_set_result(n,s,c);
+}
+
+int yaz_nfa_add_ascii_string_rule( yaz_nfa *n,
+                        char *from_string,
+                        char *to_string) {
+    size_t from_len = strlen(from_string);
+    size_t to_len = strlen(to_string);
+    yaz_nfa_char *from_buf=
+        nmem_malloc(n->nmem, from_len*sizeof(yaz_nfa_char));
+    yaz_nfa_char *to_buf=
+        nmem_malloc(n->nmem, to_len*sizeof(yaz_nfa_char));
+    size_t i;
+    for (i=0;i<from_len;i++) 
+        from_buf[i]=from_string[i];
+    for (i=0;i<to_len;i++) 
+        to_buf[i]=to_string[i];
+    return yaz_nfa_add_string_rule(n,from_buf, from_len,
+            to_buf, to_len);
+}
+
+int yaz_nfa_add_char_range_rule (yaz_nfa *n,
+        yaz_nfa_char range_start,
+        yaz_nfa_char range_end,
+        yaz_nfa_char output_range_start) {
+    yaz_nfa_state *s= 
+        yaz_nfa_add_range(n, 0, range_start, range_end);
+    yaz_nfa_converter *c=
+        yaz_nfa_create_range_converter(n,0,range_start, output_range_start);
+    return yaz_nfa_set_result(n,s,c);
+}
+
+int yaz_nfa_add_char_string_rule (yaz_nfa *n,
+        yaz_nfa_char range_start,
+        yaz_nfa_char range_end,
+        yaz_nfa_char* to_string,
+        size_t to_length) {
+    yaz_nfa_state *s= 
+        yaz_nfa_add_range(n, 0, range_start, range_end);
+    yaz_nfa_converter *c=
+        yaz_nfa_create_string_converter(n,to_string,to_length);
+    return yaz_nfa_set_result(n,s,c);
+}
+
+
+int yaz_nfa_convert_slice (yaz_nfa *n,
+        yaz_nfa_char **inbuff, 
+        size_t *incharsleft,
+        yaz_nfa_char **outbuff,
+        size_t *outcharsleft) {
+    void *resptr;
+    yaz_nfa_converter *conv;
+    int rc;
+
+    if (*outcharsleft==0)
+        rc=YAZ_NFA_NOSPACE; /* no room in outbuff */
+    else if (*incharsleft==0) 
+        rc = YAZ_NFA_SUCCESS; /* all done */
+    else {
+        rc=yaz_nfa_match(n, inbuff, incharsleft, &resptr);
+        if (rc==YAZ_NFA_SUCCESS) {
+            conv= (yaz_nfa_converter *)resptr;
+            rc=yaz_nfa_run_converters(n,conv,outbuff,outcharsleft);    
+        } else if (rc==YAZ_NFA_NOMATCH) {
+            **outbuff = **inbuff; 
+            (*outbuff)++;
+            (*inbuff)++;
+            (*outcharsleft)--;
+            (*incharsleft)--;
+            rc=YAZ_NFA_SUCCESS; 
+        }
+        /* else just return the error code */
+    }
+    return rc;
+}
 
 /* * * * * * * * *
  * Debug routines
@@ -412,17 +684,17 @@ static void dump_trans(FILE *F, yaz_nfa_transition *t ) {
     char c1;
     char c2;
     char *e;
-    c1=t->range_start;
-    c2=t->range_end;
-    e="";
+    c1 = t->range_start;
+    c2 = t->range_end;
+    e = "";
     if ( (t->range_start <= ' ') || (t->range_start>'z'))
-        c1='?';
+        c1 = '?';
     if ( (t->range_end <= ' ') || (t->range_end>'z'))
-        c2='?';
+        c2 = '?';
     if ((t->range_start==EMPTY_START) && (t->range_end==EMPTY_END)) {
-        e="(empty)";
+        e = "(empty)";
     }
-    fprintf(F,"    -> [%d]  %s '%c' %x - '%c' %x \n",
+    fprintf(F, "    -> [%d]  %s '%c' %x - '%c' %x \n",
             t->to_state->num, e,
             c1, t->range_start,
             c2, t->range_end );
@@ -431,30 +703,30 @@ static void dump_trans(FILE *F, yaz_nfa_transition *t ) {
 static void dump_state(FILE *F, yaz_nfa_state *s,
             char *(*strfunc)(void *) ) {
     yaz_nfa_transition *t;
-    char *resultstring="";
+    char *resultstring = "";
     if (s->result) {
         if (strfunc)  {
-            resultstring=(*strfunc)(s->result);
+            resultstring = (*strfunc)(s->result);
         }
         else
-            resultstring=s->result;
+            resultstring = s->result;
     }
-    fprintf(F,"  state [%d] %s %s",
-            s->num, s->result?"(FINAL)":"",resultstring );
+    fprintf(F, "  state [%d] %s %s",
+            s->num, s->result?"(final)":"", resultstring );
     if (s->backref_start) {
-        fprintf(F," start-%d",s->backref_start);
+        fprintf(F, " start-%d", s->backref_start);
     }
     if (s->backref_end) {
-        fprintf(F," end-%d",s->backref_end);
+        fprintf(F, " end-%d", s->backref_end);
     }
-    fprintf(F,"\n");
-    t=s->lasttrans;
+    fprintf(F, "\n");
+    t = s->lasttrans;
     if (!t) {
-        fprintf(F,"    (no transitions)\n");
+        fprintf(F, "    (no transitions)\n");
     } else {
         do {
-            t=t->next;
-            dump_trans(F,t);
+            t = t->next;
+            dump_trans(F, t);
         } while (t != s->lasttrans);
     }
 
@@ -464,18 +736,56 @@ void yaz_nfa_dump(FILE *F, yaz_nfa *n,
             char *(*strfunc)(void *) ) {
     yaz_nfa_state *s;
     if (!F)   /* lazy programmers can just pass 0 for F */
-        F=stdout;
-    fprintf(F,"The NFA has %d states and %d backrefs\n",
+        F = stdout;
+    fprintf(F, "The NFA has %d states and %d backrefs\n",
             n->nstates, n->nbackrefs);
-    s=n->laststate;
+    s = n->laststate;
     if (s) {
         do {
-            s=s->next;
-            dump_state(F,s, strfunc);
+            s = s->next;
+            dump_state(F, s, strfunc);
         } while (s != n->laststate);
     }
 }
 
+static char buf[5000]="";
+char *yaz_nfa_dump_converter(void *conv)
+{
+    char onebuf[500]="";
+    yaz_nfa_converter *c=conv;
+    yaz_nfa_char *cp;
+    size_t len;
+    *buf=0;
+    while (c) {
+        switch(c->type) {
+            case conv_none:
+                sprintf(onebuf,"(none)" );
+                break;
+            case conv_string:
+                sprintf(onebuf,"(string '" );
+                strcat(buf,onebuf);
+                cp=c->string;
+                len=c->strlen;
+                while (len--) {
+                    onebuf[0]=*cp++;
+                    onebuf[1]=0;
+                    strcat(buf,onebuf);
+                }
+                strcat(buf,"')");
+                onebuf[0]=0;
+                break;
+            case conv_backref:
+                sprintf(onebuf,"(backref %d) ",c->backref_no);
+                break;
+            case conv_range:
+                sprintf(onebuf,"(range %d) ",c->char_diff);
+                break;
+        }
+        strcat(buf,onebuf);
+        c=c->next;
+    } /* while */
+    return buf;
+}
 
 
 /*