From 602d9dc32e7dd66552691f0e7d55a44861e9a180 Mon Sep 17 00:00:00 2001
From: Cas Cremers <cas.cremers@gmail.com>
Date: Mon, 24 Dec 2018 14:29:02 +0100
Subject: [PATCH] Adapting subtermUnify to have state.

---
 src/arachne.c |  9 +++++----
 src/mgu.c     | 18 ++++++++++++------
 src/mgu.h     |  2 +-
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/src/arachne.c b/src/arachne.c
index 6e824ac..cbcc816 100644
--- a/src/arachne.c
+++ b/src/arachne.c
@@ -1012,7 +1012,7 @@ bind_existing_to_goal (const Binding b, const int run, const int index,
 {
   Term bigterm;
 
-  int unifiesWithKeys (Termlist substlist, Termlist keylist)
+  int unifiesWithKeys (Termlist substlist, Termlist keylist, void *state)
   {
     int old_length;
     int newgoals;
@@ -1086,7 +1086,7 @@ bind_existing_to_goal (const Binding b, const int run, const int index,
   }
 
   bigterm = roledef_shift (sys->runs[run].start, index)->message;
-  subtermUnify (bigterm, b->term, NULL, NULL, unifiesWithKeys);
+  subtermUnify (bigterm, b->term, NULL, NULL, unifiesWithKeys, NULL);
 }
 
 
@@ -1451,7 +1451,7 @@ debug_send_candidate (const Protocol p, const Role r, const Roledef rd,
 
 //! Dummy helper function for iterator; abort if sub-unification found
 int
-test_sub_unification (Termlist substlist, Termlist keylist)
+test_sub_unification (Termlist substlist, Termlist keylist, void *state)
 {
   // A unification exists; return the signal
   return false;
@@ -1555,7 +1555,8 @@ bind_this_role_send (Protocol p, Role r, Roledef rd, int index,
   debug_send_candidate (p, r, rd, index);
 
   if (!subtermUnify
-      (rd->message, (bs->binding)->term, NULL, NULL, test_sub_unification))
+      (rd->message, (bs->binding)->term, NULL, NULL, test_sub_unification,
+       NULL))
     {
       // A good candidate
       bs->found++;
diff --git a/src/mgu.c b/src/mgu.c
index ef8ccb2..a964a89 100644
--- a/src/mgu.c
+++ b/src/mgu.c
@@ -292,7 +292,8 @@ unify (Term t1, Term t2, Termlist tl, int (*callback) (), void *state)
  */
 struct su_kcb_state
 {
-  int (*callback) (Termlist, Termlist);
+  void *oldstate;
+  int (*callback) (Termlist, Termlist, void *);
   Termlist keylist;
 };
 
@@ -300,7 +301,8 @@ int
 keycallback (Termlist tl, struct su_kcb_state *ptr_kcb_state)
 {
   assert (ptr_kcb_state != NULL);
-  return ptr_kcb_state->callback (tl, ptr_kcb_state->keylist);
+  return ptr_kcb_state->callback (tl, ptr_kcb_state->keylist,
+				  ptr_kcb_state->oldstate);
 }
 
 //! Subterm unification
@@ -320,11 +322,12 @@ keycallback (Termlist tl, struct su_kcb_state *ptr_kcb_state)
  */
 int
 subtermUnify (Term tbig, Term tsmall, Termlist tl, Termlist keylist,
-	      int (*callback) (Termlist, Termlist))
+	      int (*callback) (Termlist, Termlist, void *), void *state)
 {
   int proceed;
   struct su_kcb_state kcb_state;
 
+  kcb_state.oldstate = state;
   kcb_state.callback = callback;
   kcb_state.keylist = keylist;
 
@@ -346,9 +349,11 @@ subtermUnify (Term tbig, Term tsmall, Termlist tl, Termlist keylist,
       if (realTermTuple (tbig))
 	{
 	  proceed = proceed
-	    && subtermUnify (TermOp1 (tbig), tsmall, tl, keylist, callback);
+	    && subtermUnify (TermOp1 (tbig), tsmall, tl, keylist, callback,
+			     state);
 	  proceed = proceed
-	    && subtermUnify (TermOp2 (tbig), tsmall, tl, keylist, callback);
+	    && subtermUnify (TermOp2 (tbig), tsmall, tl, keylist, callback,
+			     state);
 	}
 
       // 3. unification with encryption needed
@@ -357,7 +362,8 @@ subtermUnify (Term tbig, Term tsmall, Termlist tl, Termlist keylist,
 	  // extend the keylist
 	  keylist = termlistAdd (keylist, tbig);
 	  proceed = proceed
-	    && subtermUnify (TermOp (tbig), tsmall, tl, keylist, callback);
+	    && subtermUnify (TermOp (tbig), tsmall, tl, keylist, callback,
+			     state);
 	  // remove last item again
 	  keylist = termlistDelTerm (keylist);
 	}
diff --git a/src/mgu.h b/src/mgu.h
index f06c05e..2fc430b 100644
--- a/src/mgu.h
+++ b/src/mgu.h
@@ -39,6 +39,6 @@ int checkRoletermMatch (const Term t1, const Term t2, const Termlist tl);
 int unify (Term t1, Term t2, Termlist tl, int (*callback) (), void *state);
 int
 subtermUnify (Term tbig, Term tsmall, Termlist tl, Termlist keylist,
-	      int (*callback) (Termlist, Termlist));
+	      int (*callback) (Termlist, Termlist, void *), void *state);
 
 #endif