yap-6.3/OPTYap/tab.tries.c

/**********************************************************************
                                                               
                       The OPTYap Prolog system                
  OPTYap extends the Yap Prolog system to support or-parallel tabling
                                                               
  Copyright:   R. Rocha and NCC - University of Porto, Portugal
  File:        tab.tries.C
  version:     $Id: tab.tries.c,v 1.24 2008-05-20 18:25:37 ricroc Exp $   
                                                                     
**********************************************************************/

/* ------------------ **
**      Includes      **
** ------------------ */

#include "Yap.h"
#ifdef TABLING
#include <stdio.h>
#ifdef HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
#include "Yatom.h"
#include "Heap.h"
#include "yapio.h"
#include "tab.macros.h"


/* ----------------- **
**      Defines      **
** ----------------- */

#define TRAVERSE_NORMAL    0
#define TRAVERSE_FLOAT     1
#define TRAVERSE_FLOAT2    2
#define TRAVERSE_FLOAT_END 3
#define TRAVERSE_LONG      4
#define TRAVERSE_LONG_END  5



/* ------------------------------------- **
**      Local functions declaration      **
** ------------------------------------- */

#ifdef YAPOR
#ifdef TABLING_INNER_CUTS
static int update_answer_trie_branch(ans_node_ptr previous_node, ans_node_ptr node);
#else
static int update_answer_trie_branch(ans_node_ptr node);
#endif /* TABLING_INNER_CUTS */
#else
static void update_answer_trie_branch(ans_node_ptr node);
#endif /* YAPOR */
static void traverse_subgoal_trie(sg_node_ptr sg_node, char *str, int str_index, int *arity, int depth, int mode);
static void traverse_answer_trie(ans_node_ptr ans_node, char *str, int str_index, int *arity, int var_index, int depth, int mode);



/* ----------------------- **
**      Local inlines      **
** ----------------------- */

STD_PROTO(static inline sg_node_ptr subgoal_trie_node_check_insert, (tab_ent_ptr, sg_node_ptr, Term));
STD_PROTO(static inline ans_node_ptr answer_trie_node_check_insert, (sg_fr_ptr, ans_node_ptr, Term, int));



#ifdef TABLE_LOCK_AT_WRITE_LEVEL

static inline
sg_node_ptr subgoal_trie_node_check_insert(tab_ent_ptr tab_ent, sg_node_ptr parent_node, Term t) {
  sg_node_ptr chain_node, new_node;
  sg_hash_ptr hash;


  chain_node = TrNode_child(parent_node);


  if (chain_node == NULL) {
#ifdef ALLOC_BEFORE_CHECK
    new_subgoal_trie_node(new_node, t, NULL, parent_node, NULL);
#endif /* ALLOC_BEFORE_CHECK */
    LOCK_TABLE(parent_node);
    if (TrNode_child(parent_node)) {
      chain_node = TrNode_child(parent_node);
      if (IS_SUBGOAL_HASH(chain_node)) {
#ifdef ALLOC_BEFORE_CHECK
        FREE_SUBGOAL_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
        UNLOCK_TABLE(parent_node);
        hash = (sg_hash_ptr) chain_node;
        goto subgoal_hash;
      }
      do {
        if (TrNode_entry(chain_node) == t) {
#ifdef ALLOC_BEFORE_CHECK
          FREE_SUBGOAL_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
          UNLOCK_TABLE(parent_node);
          return chain_node;
        }
        chain_node = TrNode_next(chain_node);
      } while (chain_node);
#ifdef ALLOC_BEFORE_CHECK
      TrNode_next(new_node) = TrNode_child(parent_node);
#else
      new_subgoal_trie_node(new_node, t, NULL, parent_node, TrNode_child(parent_node));
    } else {
      new_subgoal_trie_node(new_node, t, NULL, parent_node, NULL);
#endif /* ALLOC_BEFORE_CHECK */
    }
    TrNode_child(parent_node) = new_node;
    UNLOCK_TABLE(parent_node);
    return new_node;
  } 


  if (! IS_SUBGOAL_HASH(chain_node)) {
    sg_node_ptr first_node;
    int count_nodes;

    first_node = chain_node;
    count_nodes = 0;
    do {
      if (TrNode_entry(chain_node) == t) {
        return chain_node;
      }
      count_nodes++;
      chain_node = TrNode_next(chain_node);
    } while (chain_node);
#ifdef ALLOC_BEFORE_CHECK
    new_subgoal_trie_node(new_node, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    LOCK_TABLE(parent_node);
    if (first_node != TrNode_child(parent_node)) {
      chain_node = TrNode_child(parent_node);
      if (IS_SUBGOAL_HASH(chain_node)) {
#ifdef ALLOC_BEFORE_CHECK
        FREE_SUBGOAL_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
        UNLOCK_TABLE(parent_node);
        hash = (sg_hash_ptr) chain_node;
        goto subgoal_hash;
      }
      do {
        if (TrNode_entry(chain_node) == t) {
#ifdef ALLOC_BEFORE_CHECK
          FREE_SUBGOAL_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
          UNLOCK_TABLE(parent_node);
          return chain_node;
        }
        count_nodes++;
        chain_node = TrNode_next(chain_node);
      } while (chain_node != first_node);
#ifdef ALLOC_BEFORE_CHECK
      TrNode_next(new_node) = TrNode_child(parent_node);
#else
      new_subgoal_trie_node(new_node, t, NULL, parent_node, TrNode_child(parent_node));
    } else {
      new_subgoal_trie_node(new_node, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    }
    if (count_nodes >= MAX_NODES_PER_TRIE_LEVEL) {
      /* alloc a new hash */
      sg_node_ptr next_node, *bucket;
      new_subgoal_hash(hash, count_nodes, tab_ent);
      chain_node = new_node;
      do {
        bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), BASE_HASH_BUCKETS - 1));
        next_node = TrNode_next(chain_node);
        TrNode_next(chain_node) = *bucket;
        *bucket = chain_node;
        chain_node = next_node;
      } while (chain_node);
      TrNode_child(parent_node) = (sg_node_ptr) hash;
    } else {
      TrNode_child(parent_node) = new_node;
    }
    UNLOCK_TABLE(parent_node);
    return new_node;
  }


  hash = (sg_hash_ptr) chain_node; 
subgoal_hash:
  { /* trie nodes with hashing */
    sg_node_ptr *bucket, first_node;
    int seed, count_nodes;

    seed = Hash_seed(hash);
    bucket = Hash_bucket(hash, HASH_TERM(t, seed));
    first_node = chain_node = *bucket;
    count_nodes = 0;
    while (chain_node) {
      if (TrNode_entry(chain_node) == t) {
        return chain_node;
      }
      count_nodes++;
      chain_node = TrNode_next(chain_node);
    }
#ifdef ALLOC_BEFORE_CHECK
    new_subgoal_trie_node(new_node, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    LOCK_TABLE(parent_node);
    if (seed != Hash_seed(hash)) {
      /* the hash has been expanded */ 
#ifdef ALLOC_BEFORE_CHECK
      FREE_SUBGOAL_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
      UNLOCK_TABLE(parent_node);
      goto subgoal_hash;
    }
    if (first_node != *bucket) {
      chain_node = *bucket;
      do {
        if (TrNode_entry(chain_node) == t) {
#ifdef ALLOC_BEFORE_CHECK
          FREE_SUBGOAL_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
          UNLOCK_TABLE(parent_node);
          return chain_node;
        }
        count_nodes++;
        chain_node = TrNode_next(chain_node);
      } while (chain_node != first_node);
#ifdef ALLOC_BEFORE_CHECK
      TrNode_next(new_node) = *bucket;
#else
      new_subgoal_trie_node(new_node, t, NULL, parent_node, *bucket);
    } else {
      new_subgoal_trie_node(new_node, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    }
    *bucket = new_node;
    Hash_num_nodes(hash)++;
    if (count_nodes >= MAX_NODES_PER_BUCKET && Hash_num_nodes(hash) > Hash_num_buckets(hash)) {
      /* expand current hash */ 
      sg_node_ptr next_node, *first_old_bucket, *old_bucket;
      first_old_bucket = Hash_buckets(hash);
      old_bucket = first_old_bucket + Hash_num_buckets(hash);
      seed = Hash_num_buckets(hash) * 2;
      ALLOC_HASH_BUCKETS(Hash_buckets(hash), seed);
      seed--;
      do {
        if (*--old_bucket) {
          chain_node = *old_bucket;
          do {
            bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), seed));
            next_node = TrNode_next(chain_node);
            TrNode_next(chain_node) = *bucket;
            *bucket = chain_node;
            chain_node = next_node;
          } while (chain_node);
        }
      } while (old_bucket != first_old_bucket);
      Hash_num_buckets(hash) = seed + 1;
      FREE_HASH_BUCKETS(first_old_bucket);
    }
    UNLOCK_TABLE(parent_node);
    return new_node;
  }
}


static inline 
ans_node_ptr answer_trie_node_check_insert(sg_fr_ptr sg_fr, ans_node_ptr parent_node, Term t, int instr) {
  ans_node_ptr chain_node, new_node;
  ans_hash_ptr hash;

#ifdef TABLING_ERRORS
  if (IS_ANSWER_LEAF_NODE(parent_node))
    TABLING_ERROR_MESSAGE("IS_ANSWER_LEAF_NODE(parent_node) (answer_trie_node_check_insert)");
#endif /* TABLING_ERRORS */


  chain_node = TrNode_child(parent_node);


  if (chain_node == NULL) {
#ifdef ALLOC_BEFORE_CHECK
    new_answer_trie_node(new_node, instr, t, NULL, parent_node, NULL);
#endif /* ALLOC_BEFORE_CHECK */
    LOCK_TABLE(parent_node);
    if (TrNode_child(parent_node)) {
      chain_node = TrNode_child(parent_node);
      if (IS_ANSWER_HASH(chain_node)) {
#ifdef ALLOC_BEFORE_CHECK
        FREE_ANSWER_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
        UNLOCK_TABLE(parent_node);
        hash = (ans_hash_ptr) chain_node;
        goto answer_hash;
      }
      do {
        if (TrNode_entry(chain_node) == t) {
#ifdef ALLOC_BEFORE_CHECK
          FREE_ANSWER_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
          UNLOCK_TABLE(parent_node);
          return chain_node;
        }
        chain_node = TrNode_next(chain_node);
      } while (chain_node);
#ifdef ALLOC_BEFORE_CHECK
      TrNode_next(new_node) = TrNode_child(parent_node);
#else
      new_answer_trie_node(new_node, instr, t, NULL, parent_node, TrNode_child(parent_node));
    } else {
      new_answer_trie_node(new_node, instr, t, NULL, parent_node, NULL);
#endif /* ALLOC_BEFORE_CHECK */
    }
    TrNode_child(parent_node) = new_node;
    UNLOCK_TABLE(parent_node);
    return new_node;
  } 


  if (! IS_ANSWER_HASH(chain_node)) {
    ans_node_ptr first_node;
    int count_nodes;

    first_node = chain_node;
    count_nodes = 0;
    do {
      if (TrNode_entry(chain_node) == t) {
        return chain_node;
      }
      count_nodes++;
      chain_node = TrNode_next(chain_node);
    } while (chain_node);
#ifdef ALLOC_BEFORE_CHECK
    new_answer_trie_node(new_node, instr, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    LOCK_TABLE(parent_node);
    if (first_node != TrNode_child(parent_node)) {
      chain_node = TrNode_child(parent_node);
      if (IS_ANSWER_HASH(chain_node)) {
#ifdef ALLOC_BEFORE_CHECK
        FREE_ANSWER_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
        UNLOCK_TABLE(parent_node);
        hash = (ans_hash_ptr) chain_node; 
        goto answer_hash;
      }
      do {
        if (TrNode_entry(chain_node) == t) {
#ifdef ALLOC_BEFORE_CHECK
          FREE_ANSWER_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
          UNLOCK_TABLE(parent_node);
          return chain_node;
        }
        count_nodes++;
        chain_node = TrNode_next(chain_node);
      } while (chain_node != first_node);
#ifdef ALLOC_BEFORE_CHECK
      TrNode_next(new_node) = TrNode_child(parent_node);
#else
      new_answer_trie_node(new_node, instr, t, NULL, parent_node, TrNode_child(parent_node));
    } else {
      new_answer_trie_node(new_node, instr, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    }
    if (count_nodes >= MAX_NODES_PER_TRIE_LEVEL) {
      /* alloc a new hash */
      ans_node_ptr next_node, *bucket;
      new_answer_hash(hash, count_nodes, sg_fr);
      chain_node = new_node;
      do {
        bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), BASE_HASH_BUCKETS - 1));
        next_node = TrNode_next(chain_node);
        TrNode_next(chain_node) = *bucket;
        *bucket = chain_node;
        chain_node = next_node;
      } while (chain_node);
      TrNode_child(parent_node) = (ans_node_ptr) hash;
    } else {
      TrNode_child(parent_node) = new_node;
    }
    UNLOCK_TABLE(parent_node);
    return new_node;
  }


  hash = (ans_hash_ptr) chain_node; 
answer_hash:
  { /* trie nodes with hashing */
    ans_node_ptr *bucket, first_node;
    int seed, count_nodes;

    seed = Hash_seed(hash);
    bucket = Hash_bucket(hash, HASH_TERM(t, seed));
    first_node = chain_node = *bucket;
    count_nodes = 0;
    while (chain_node) {
      if (TrNode_entry(chain_node) == t) {
        return chain_node;
      }
      count_nodes++;
      chain_node = TrNode_next(chain_node);
    }
#ifdef ALLOC_BEFORE_CHECK
    new_answer_trie_node(new_node, instr, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    LOCK_TABLE(parent_node);
    if (seed != Hash_seed(hash)) {
      /* the hash has been expanded */ 
#ifdef ALLOC_BEFORE_CHECK
      FREE_ANSWER_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
      UNLOCK_TABLE(parent_node);
      goto answer_hash;
    }
    if (first_node != *bucket) {
      chain_node = *bucket;
      do {
        if (TrNode_entry(chain_node) == t) {
#ifdef ALLOC_BEFORE_CHECK
          FREE_ANSWER_TRIE_NODE(new_node);
#endif /* ALLOC_BEFORE_CHECK */
          UNLOCK_TABLE(parent_node);
          return chain_node;
        }
        count_nodes++;
        chain_node = TrNode_next(chain_node);
      } while (chain_node != first_node);
#ifdef ALLOC_BEFORE_CHECK
      TrNode_next(new_node) = *bucket;
#else
      new_answer_trie_node(new_node, instr, t, NULL, parent_node, *bucket);
    } else {
      new_answer_trie_node(new_node, instr, t, NULL, parent_node, first_node);
#endif /* ALLOC_BEFORE_CHECK */
    }
    *bucket = new_node;
    Hash_num_nodes(hash)++;
    if (count_nodes >= MAX_NODES_PER_BUCKET && Hash_num_nodes(hash) > Hash_num_buckets(hash)) {
      /* expand current hash */ 
      ans_node_ptr next_node, *first_old_bucket, *old_bucket;
      first_old_bucket = Hash_buckets(hash);
      old_bucket = first_old_bucket + Hash_num_buckets(hash);
      seed = Hash_num_buckets(hash) * 2;
      ALLOC_HASH_BUCKETS(Hash_buckets(hash), seed);
      seed--;
      do {
        if (*--old_bucket) {
          chain_node = *old_bucket;
          do {
            bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), seed));
            next_node = TrNode_next(chain_node);
            TrNode_next(chain_node) = *bucket;
            *bucket = chain_node;
            chain_node = next_node;
          } while (chain_node);
        }
      } while (old_bucket != first_old_bucket);
      Hash_num_buckets(hash) = seed + 1;
      FREE_HASH_BUCKETS(first_old_bucket);
    }
    UNLOCK_TABLE(parent_node);
    return new_node;
  }
}
#else  /* TABLE_LOCK_AT_ENTRY_LEVEL || TABLE_LOCK_AT_NODE_LEVEL || ! YAPOR */


#ifdef TABLE_LOCK_AT_NODE_LEVEL
#define LOCK_NODE(NODE)  TRIE_LOCK(TrNode_lock(NODE))
#define UNLOCK_NODE(NODE)   UNLOCK(TrNode_lock(NODE))
#else
#define LOCK_NODE(NODE)
#define UNLOCK_NODE(NODE)
#endif /* TABLE_LOCK_AT_NODE_LEVEL */


static inline
sg_node_ptr subgoal_trie_node_check_insert(tab_ent_ptr tab_ent, sg_node_ptr parent_node, Term t) {
  sg_node_ptr child_node;

  LOCK_NODE(parent_node);
  child_node = TrNode_child(parent_node);

  if (child_node == NULL) {
    new_subgoal_trie_node(child_node, t, NULL, parent_node, NULL);
    TrNode_child(parent_node) = child_node;
    UNLOCK_NODE(parent_node);
    return child_node;
  }

  if (! IS_SUBGOAL_HASH(child_node)) {
    int count_nodes;
    count_nodes = 0;
    do {
      if (TrNode_entry(child_node) == t) {
        UNLOCK_NODE(parent_node);
        return child_node;
      }
      count_nodes++;
      child_node = TrNode_next(child_node);
    } while (child_node);
    new_subgoal_trie_node(child_node, t, NULL, parent_node, TrNode_child(parent_node));
    if (count_nodes >= MAX_NODES_PER_TRIE_LEVEL) {
      /* alloc a new hash */
      sg_hash_ptr hash;
      sg_node_ptr chain_node, next_node, *bucket;
      new_subgoal_hash(hash, count_nodes, tab_ent);
      chain_node = child_node;
      do {
        bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), BASE_HASH_BUCKETS - 1));
        next_node = TrNode_next(chain_node);
        TrNode_next(chain_node) = *bucket;
        *bucket = chain_node;
        chain_node = next_node;
      } while (chain_node);
      TrNode_child(parent_node) = (sg_node_ptr) hash;
    } else {
      TrNode_child(parent_node) = child_node;
    }
    UNLOCK_NODE(parent_node);
    return child_node;
  }

  { /* trie nodes with hashing */
    sg_hash_ptr hash;
    sg_node_ptr *bucket;
    int count_nodes;
    hash = (sg_hash_ptr) child_node; 
    bucket = Hash_bucket(hash, HASH_TERM(t, Hash_seed(hash)));
    child_node = *bucket;
    count_nodes = 0;
    while (child_node) {
      if (TrNode_entry(child_node) == t) {
        UNLOCK_NODE(parent_node);
        return child_node;
      }
      count_nodes++;
      child_node = TrNode_next(child_node);
    } while (child_node);
    Hash_num_nodes(hash)++;
    new_subgoal_trie_node(child_node, t, NULL, parent_node, *bucket);
    *bucket = child_node;
    if (count_nodes >= MAX_NODES_PER_BUCKET && Hash_num_nodes(hash) > Hash_num_buckets(hash)) {
      /* expand current hash */
      sg_node_ptr chain_node, next_node, *first_old_bucket, *old_bucket;
      int seed;
      first_old_bucket = Hash_buckets(hash);
      old_bucket = first_old_bucket + Hash_num_buckets(hash);
      Hash_num_buckets(hash) *= 2;
      ALLOC_HASH_BUCKETS(Hash_buckets(hash), Hash_num_buckets(hash)); 
      seed = Hash_num_buckets(hash) - 1;
      do {
        if (*--old_bucket) {
          chain_node = *old_bucket;
          do {
            bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), seed));
            next_node = TrNode_next(chain_node);
            TrNode_next(chain_node) = *bucket;
            *bucket = chain_node;
            chain_node = next_node;
          } while (chain_node);
        }
      } while (old_bucket != first_old_bucket);
      FREE_HASH_BUCKETS(first_old_bucket);
    }
    UNLOCK_NODE(parent_node);
    return child_node;
  }
}


static inline 
ans_node_ptr answer_trie_node_check_insert(sg_fr_ptr sg_fr, ans_node_ptr parent_node, Term t, int instr) {
  ans_node_ptr child_node;

#ifdef TABLING_ERRORS
  if (IS_ANSWER_LEAF_NODE(parent_node))
    TABLING_ERROR_MESSAGE("IS_ANSWER_LEAF_NODE(parent_node) (answer_trie_node_check_insert)");
#endif /* TABLING_ERRORS */

  LOCK_NODE(parent_node);
  child_node = TrNode_child(parent_node);

  if (child_node == NULL) {
    new_answer_trie_node(child_node, instr, t, NULL, parent_node, NULL);
    TrNode_child(parent_node) = child_node;
    UNLOCK_NODE(parent_node);
    return child_node;
  }

  if (! IS_ANSWER_HASH(child_node)) {
    int count_nodes;
    count_nodes = 0;
    do {
      if (TrNode_entry(child_node) == t) {
        UNLOCK_NODE(parent_node);
        return child_node;
      }
      count_nodes++;
      child_node = TrNode_next(child_node);
    } while (child_node);
    new_answer_trie_node(child_node, instr, t, NULL, parent_node, TrNode_child(parent_node));
    if (count_nodes >= MAX_NODES_PER_TRIE_LEVEL) {
      /* alloc a new hash */
      ans_hash_ptr hash;
      ans_node_ptr chain_node, next_node, *bucket;
      new_answer_hash(hash, count_nodes, sg_fr);
      chain_node = child_node;
      do {
        bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), BASE_HASH_BUCKETS - 1));
        next_node = TrNode_next(chain_node);
        TrNode_next(chain_node) = *bucket;
        *bucket = chain_node;
        chain_node = next_node;
      } while (chain_node);
      TrNode_child(parent_node) = (ans_node_ptr) hash;
    } else {
      TrNode_child(parent_node) = child_node;
    }
    UNLOCK_NODE(parent_node);
    return child_node;
  }

  { /* trie nodes with hashing */
    ans_hash_ptr hash;
    ans_node_ptr *bucket;
    int count_nodes;
    hash = (ans_hash_ptr) child_node; 
    bucket = Hash_bucket(hash, HASH_TERM(t, Hash_seed(hash)));
    child_node = *bucket;
    count_nodes = 0;
    while (child_node) {
      if (TrNode_entry(child_node) == t) {
        UNLOCK_NODE(parent_node);
        return child_node;
      }
      count_nodes++;
      child_node = TrNode_next(child_node);
    } while (child_node);
    Hash_num_nodes(hash)++;
    new_answer_trie_node(child_node, instr, t, NULL, parent_node, *bucket);
    *bucket = child_node;
    if (count_nodes >= MAX_NODES_PER_BUCKET && Hash_num_nodes(hash) > Hash_num_buckets(hash)) {
      /* expand current hash */ 
      ans_node_ptr chain_node, next_node, *first_old_bucket, *old_bucket;
      int seed;
      first_old_bucket = Hash_buckets(hash);
      old_bucket = first_old_bucket + Hash_num_buckets(hash);
      Hash_num_buckets(hash) *= 2;
      ALLOC_HASH_BUCKETS(Hash_buckets(hash), Hash_num_buckets(hash)); 
      seed = Hash_num_buckets(hash) - 1;
      do {
        if (*--old_bucket) {
          chain_node = *old_bucket;
          do {
            bucket = Hash_bucket(hash, HASH_TERM(TrNode_entry(chain_node), seed));
            next_node = TrNode_next(chain_node);
            TrNode_next(chain_node) = *bucket;
            *bucket = chain_node;
            chain_node = next_node;
          } while (chain_node);
        }
      } while (old_bucket != first_old_bucket);
      FREE_HASH_BUCKETS(first_old_bucket);
    }
    UNLOCK_NODE(parent_node);
    return child_node;
  }
}
#endif /* TABLE_LOCK_LEVEL */



/* -------------------------- **
**      Global functions      **
** -------------------------- */

sg_fr_ptr subgoal_search(yamop *preg, CELL **Yaddr) {
  int i, j, count_vars, arity;
  CELL *stack_vars, *stack_terms_limit, *stack_terms_base, *stack_terms;
  sg_node_ptr current_sg_node;
  tab_ent_ptr tab_ent;
  sg_fr_ptr sg_fr;

  arity = preg->u.Otapl.s;
  tab_ent = preg->u.Otapl.te;
  count_vars = 0;
  stack_vars = *Yaddr;
  stack_terms_limit = (CELL *)TR;
  stack_terms_base = stack_terms = (CELL *)Yap_TrailTop;
  current_sg_node = TabEnt_subgoal_trie(tab_ent);

#ifdef TABLE_LOCK_AT_ENTRY_LEVEL
  LOCK(TabEnt_lock(tab_ent));
#endif /* TABLE_LOCK_LEVEL */
  for (i = 1; i <= arity; i++) {
    STACK_CHECK_EXPAND(stack_terms, stack_terms_limit, stack_terms_base);
    STACK_PUSH_UP(Deref(XREGS[i]), stack_terms);
    do {
      Term t = STACK_POP_DOWN(stack_terms);
      if (IsVarTerm(t)) {
	if (IsTableVarTerm(t)) {
	  t = MakeTableVarTerm(VarIndexOfTerm(t));
	  current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, t);
	} else {
	  if (count_vars == MAX_TABLE_VARS)
	    Yap_Error(INTERNAL_ERROR, TermNil, "MAX_TABLE_VARS exceeded (subgoal_search)");
	  STACK_PUSH_UP(t, stack_vars);
	  *((CELL *)t) = GLOBAL_table_var_enumerator(count_vars);
	  t = MakeTableVarTerm(count_vars);
	  count_vars++;
	  current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, t);
	}
      } else if (IsAtomOrIntTerm(t)) {
	current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, t);
      } else if (IsPairTerm(t)) {
#ifdef TRIE_COMPACT_PAIRS
	CELL *aux = RepPair(t);
	if (aux == PairTermMark) {
	  t = STACK_POP_DOWN(stack_terms);
	  if (IsPairTerm(t)) {
	    aux = RepPair(t);
	    t = Deref(*(aux + 1));
	    if (t == TermNil) {
	      current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, CompactPairEndList);
	    } else {
	      /* STACK_CHECK_EXPAND(stack_terms, stack_terms_limit + 2, stack_terms_base); */
	      /* STACK_CHECK_EXPAND is not necessary here because the situation of pushing **
	      ** up 3 terms has already initially checked for the CompactPairInit term */
	      STACK_PUSH_UP(t, stack_terms);
	      STACK_PUSH_UP(AbsPair(PairTermMark), stack_terms);
	    }
	    STACK_PUSH_UP(Deref(*aux), stack_terms);
	  } else {
            current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, CompactPairEndTerm);
	    STACK_PUSH_UP(t, stack_terms);
	  }
	} else {
	  current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, CompactPairInit);
	  t = Deref(*(aux + 1));
	  if (t == TermNil) {
	    current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, CompactPairEndList);
	  } else {
	    STACK_CHECK_EXPAND(stack_terms, stack_terms_limit + 2, stack_terms_base);
	    STACK_PUSH_UP(t, stack_terms);
	    STACK_PUSH_UP(AbsPair(PairTermMark), stack_terms);
	  }
	  STACK_PUSH_UP(Deref(*aux), stack_terms);
	}
#else
	current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, AbsPair(NULL));
	STACK_CHECK_EXPAND(stack_terms, stack_terms_limit + 1, stack_terms_base);
	STACK_PUSH_UP(Deref(*(RepPair(t) + 1)), stack_terms);
	STACK_PUSH_UP(Deref(*(RepPair(t))), stack_terms);
#endif /* TRIE_COMPACT_PAIRS */
      } else if (IsApplTerm(t)) {
	Functor f = FunctorOfTerm(t);
	current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, AbsAppl((Term *)f));
	if (f == FunctorDouble) {
	  volatile Float dbl = FloatOfTerm(t);
	  volatile Term *t_dbl = (Term *)((void *) &dbl);
#if SIZEOF_DOUBLE == 2 * SIZEOF_INT_P
	  current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, *(t_dbl + 1));
#endif /* SIZEOF_DOUBLE x SIZEOF_INT_P */
	  current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, *t_dbl);
	} else if (f == FunctorLongInt) {
	  Int li = LongIntOfTerm(t);
	  current_sg_node = subgoal_trie_node_check_insert(tab_ent, current_sg_node, li);
	} else if (f == FunctorDBRef) {
	  Yap_Error(INTERNAL_ERROR, TermNil, "unsupported type tag (FunctorDBRef in subgoal_search)");
	} else if (f == FunctorBigInt) {
	  Yap_Error(INTERNAL_ERROR, TermNil, "unsupported type tag (FunctorBigInt in subgoal_search)");	  
	} else {
          STACK_CHECK_EXPAND(stack_terms, stack_terms_limit + ArityOfFunctor(f) - 1, stack_terms_base);
	  for (j = ArityOfFunctor(f); j >= 1; j--)
	    STACK_PUSH_UP(Deref(*(RepAppl(t) + j)), stack_terms);
	}
      } else {
	Yap_Error(INTERNAL_ERROR, TermNil, "unknown type tag (subgoal_search)");
      }
    } while (STACK_NOT_EMPTY(stack_terms, stack_terms_base));
  }
#if defined(TABLE_LOCK_AT_NODE_LEVEL)
  LOCK(TrNode_lock(current_sg_node));
#elif defined(TABLE_LOCK_AT_WRITE_LEVEL)
  LOCK_TABLE(current_sg_node);
#endif /* TABLE_LOCK_LEVEL */
  if (TrNode_sg_fr(current_sg_node) == NULL) {
    /* new tabled subgoal */
    new_subgoal_frame(sg_fr, preg);
    TrNode_sg_fr(current_sg_node) = (sg_node_ptr) sg_fr;
  } else {
    sg_fr = (sg_fr_ptr) TrNode_sg_fr(current_sg_node);
#ifdef LIMIT_TABLING
    if (SgFr_state(sg_fr) <= ready) {  /* incomplete or ready */
      remove_from_global_sg_fr_list(sg_fr);
    }
#endif /* LIMIT_TABLING */
  }
#if defined(TABLE_LOCK_AT_ENTRY_LEVEL)
  UNLOCK(TabEnt_lock(tab_ent));
#elif defined(TABLE_LOCK_AT_NODE_LEVEL)
  UNLOCK(TrNode_lock(current_sg_node));
#elif defined(TABLE_LOCK_AT_WRITE_LEVEL)
  UNLOCK_TABLE(current_sg_node);
#endif /* TABLE_LOCK_LEVEL */

  STACK_PUSH_UP(count_vars, stack_vars);
  *Yaddr = stack_vars++;
  /* reset variables */
  while (count_vars--) {
    Term t = STACK_POP_DOWN(stack_vars);
    RESET_VARIABLE(t);
  }

  return sg_fr;
}


ans_node_ptr answer_search(sg_fr_ptr sg_fr, CELL *subs_ptr) {
  int i, j, count_vars, subs_arity;
  CELL *stack_vars, *stack_terms_base, *stack_terms;
  ans_node_ptr current_ans_node;
#ifdef TRIE_COMPACT_PAIRS
  int in_new_pair = 0;
#else
#define in_new_pair 0
#endif /* TRIE_COMPACT_PAIRS */

  count_vars = 0;
  subs_arity = *subs_ptr;
  stack_vars = (CELL *)TR;
  stack_terms_base = stack_terms = (CELL *)Yap_TrailTop;
  current_ans_node = SgFr_answer_trie(sg_fr);

  for (i = subs_arity; i >= 1; i--) {
    STACK_CHECK_EXPAND(stack_terms, stack_vars, stack_terms_base);
    STACK_PUSH_UP(Deref(*(subs_ptr + i)), stack_terms);
#ifdef TABLING_ERRORS
    if (IsNonVarTerm(*stack_terms))
      TABLING_ERROR_MESSAGE("IsNonVarTem(*stack_terms) (answer_search)");
#endif /* TABLING_ERRORS */
    do {
      Term t = STACK_POP_DOWN(stack_terms);
      if (IsVarTerm(t)) {
	t = Deref(t);
	if (IsTableVarTerm(t)) {
	  t = MakeTableVarTerm(VarIndexOfTerm(t));
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, t, _trie_retry_val + in_new_pair);
	} else {
	  if (count_vars == MAX_TABLE_VARS)
	    Yap_Error(INTERNAL_ERROR, TermNil, "MAX_TABLE_VARS exceeded (answer_search)");
	  STACK_PUSH_DOWN(t, stack_vars);
	  *((CELL *)t) = GLOBAL_table_var_enumerator(count_vars);
	  t = MakeTableVarTerm(count_vars);
	  count_vars++;
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, t, _trie_retry_var + in_new_pair);
	}
#ifdef TRIE_COMPACT_PAIRS
	in_new_pair = 0;
#endif /* TRIE_COMPACT_PAIRS */
      } else if (IsAtomOrIntTerm(t)) {
	current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, t, _trie_retry_atom + in_new_pair);
#ifdef TRIE_COMPACT_PAIRS
	in_new_pair = 0;
#endif /* TRIE_COMPACT_PAIRS */
      } else if (IsPairTerm(t)) {
#ifdef TRIE_COMPACT_PAIRS
	CELL *aux = RepPair(t);
	if (aux == PairTermMark) {
	  t = STACK_POP_DOWN(stack_terms);
	  if (IsPairTerm(t)) {
	    aux = RepPair(t);
	    t = Deref(*(aux + 1));
	    if (t == TermNil) {
	      current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, CompactPairEndList, _trie_retry_pair);
	    } else {
	      /* STACK_CHECK_EXPAND(stack_terms, stack_vars + 2, stack_terms_base); */
	      /* STACK_CHECK_EXPAND is not necessary here because the situation of pushing **
	      ** up 3 terms has already initially checked for the CompactPairInit term */
	      STACK_PUSH_UP(t, stack_terms);
	      STACK_PUSH_UP(AbsPair(PairTermMark), stack_terms);
	      in_new_pair = 4;
	    }
	    STACK_PUSH_UP(Deref(*aux), stack_terms);
	  } else {
	    current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, CompactPairEndTerm, _trie_retry_null);
	    STACK_PUSH_UP(t, stack_terms);
	  }         
	} else {
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, CompactPairInit, _trie_retry_null + in_new_pair);
	  t = Deref(*(aux + 1));
	  if (t == TermNil) {
	    current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, CompactPairEndList, _trie_retry_pair);
	    in_new_pair = 0;
	  } else {
	    STACK_CHECK_EXPAND(stack_terms, stack_vars + 2, stack_terms_base);
	    STACK_PUSH_UP(t, stack_terms);
	    STACK_PUSH_UP(AbsPair(PairTermMark), stack_terms);
	    in_new_pair = 4;
	  }
	  STACK_PUSH_UP(Deref(*aux), stack_terms);
	}
#else
	current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, AbsPair(NULL), _trie_retry_pair);
	STACK_CHECK_EXPAND(stack_terms, stack_vars + 1, stack_terms_base);
	STACK_PUSH_UP(Deref(*(RepPair(t) + 1)), stack_terms);
	STACK_PUSH_UP(Deref(*(RepPair(t))), stack_terms);
#endif /* TRIE_COMPACT_PAIRS */
      } else if (IsApplTerm(t)) {
	Functor f = FunctorOfTerm(t);
	if (f == FunctorDouble) {
	  volatile Float dbl = FloatOfTerm(t);
	  volatile Term *t_dbl = (Term *)((void *) &dbl);
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, AbsAppl((Term *)f), _trie_retry_null + in_new_pair);
#if SIZEOF_DOUBLE == 2 * SIZEOF_INT_P
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, *(t_dbl + 1), _trie_retry_extension);
#endif /* SIZEOF_DOUBLE x SIZEOF_INT_P */
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, *t_dbl, _trie_retry_extension);
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, AbsAppl((Term *)f), _trie_retry_float);
	} else if (f == FunctorLongInt) {
	  Int li = LongIntOfTerm (t);
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, AbsAppl((Term *)f), _trie_retry_null + in_new_pair);
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, li, _trie_retry_extension);
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, AbsAppl((Term *)f), _trie_retry_long);
	} else if (f == FunctorDBRef) {
	  Yap_Error(INTERNAL_ERROR, TermNil, "unsupported type tag (FunctorDBRef in answer_search)");
	} else if (f == FunctorBigInt) {
	  Yap_Error(INTERNAL_ERROR, TermNil, "unsupported type tag (FunctorBigInt in answer_search)");
	} else {
	  current_ans_node = answer_trie_node_check_insert(sg_fr, current_ans_node, AbsAppl((Term *)f), _trie_retry_struct + in_new_pair);
          STACK_CHECK_EXPAND(stack_terms, stack_vars + ArityOfFunctor(f) - 1, stack_terms_base);
	  for (j = ArityOfFunctor(f); j >= 1; j--)
	    STACK_PUSH_UP(Deref(*(RepAppl(t) + j)), stack_terms);
	}
#ifdef TRIE_COMPACT_PAIRS
	in_new_pair = 0;
#endif /* TRIE_COMPACT_PAIRS */
      } else {
	Yap_Error(INTERNAL_ERROR, TermNil, "unknown type tag (answer_search)");
      }
    } while (STACK_NOT_EMPTY(stack_terms, stack_terms_base));
  }

  /* reset variables */
  while (count_vars--) {
    Term t = STACK_POP_UP(stack_vars);
    RESET_VARIABLE(t);
  }

  return current_ans_node;
}


void load_answer_trie(ans_node_ptr ans_node, CELL *subs_ptr) {
  CELL *stack_vars_base, *stack_vars, *stack_terms_base, *stack_terms;
  int subs_arity, i, n_vars = -1;
  Term t;
#ifdef TRIE_COMPACT_PAIRS
  int stack_terms_pair_offset = 0;
#endif /* TRIE_COMPACT_PAIRS */

  if ((subs_arity = *subs_ptr) == 0)
    return;

#ifdef TABLING_ERRORS
  if (H < H_FZ)
    TABLING_ERROR_MESSAGE("H < H_FZ (load_answer_trie)");
#endif /* TABLING_ERRORS */
  stack_vars_base = stack_vars = (CELL *)TR;
  stack_terms_base = stack_terms = (CELL *)Yap_TrailTop;

  t = TrNode_entry(ans_node);
  ans_node = UNTAG_ANSWER_LEAF_NODE(TrNode_parent(ans_node));
  do {
    if (IsVarTerm(t)) {
      int var_index = VarIndexOfTableTerm(t);
      STACK_CHECK_EXPAND(stack_terms, stack_vars_base + var_index + 1, stack_terms_base);
      if(var_index > n_vars) {
	for (i = var_index; i > n_vars; i--)
	  stack_vars_base[i] = 0; 
	n_vars = var_index;
	stack_vars = stack_vars_base + var_index;
      }  
      if (stack_vars_base[var_index] == 0)
	stack_vars_base[var_index] = MkVarTerm(); 
      STACK_PUSH_UP(stack_vars_base[var_index], stack_terms);
    } else if (IsAtomOrIntTerm(t)) {
      STACK_CHECK_EXPAND(stack_terms, stack_vars, stack_terms_base);
      STACK_PUSH_UP(t, stack_terms);
    } else if (IsPairTerm(t)) {
#ifdef TRIE_COMPACT_PAIRS
      if (t == CompactPairInit) { 
	Term *stack_aux = stack_terms_base - stack_terms_pair_offset;
	Term head, tail = STACK_POP_UP(stack_aux);
	while (STACK_NOT_EMPTY(stack_aux, stack_terms)) {
	  head = STACK_POP_UP(stack_aux);
	  tail = MkPairTerm(head, tail);
	}
	stack_terms = stack_terms_base - stack_terms_pair_offset;
	stack_terms_pair_offset = (int) STACK_POP_DOWN(stack_terms);
	STACK_PUSH_UP(tail, stack_terms);
      } else {  /* CompactPairEndList / CompactPairEndTerm */
	Term last;
	STACK_CHECK_EXPAND(stack_terms, stack_vars + 1, stack_terms_base);
	last = STACK_POP_DOWN(stack_terms);
	STACK_PUSH_UP(stack_terms_pair_offset, stack_terms);
	stack_terms_pair_offset = (int) (stack_terms_base - stack_terms);
	if (t == CompactPairEndList)
	  STACK_PUSH_UP(TermNil, stack_terms);
	STACK_PUSH_UP(last, stack_terms);
      }
#else
      Term head = STACK_POP_DOWN(stack_terms);
      Term tail = STACK_POP_DOWN(stack_terms);
      t = MkPairTerm(head, tail);
      STACK_PUSH_UP(t, stack_terms);
#endif /* TRIE_COMPACT_PAIRS */
    } else if (IsApplTerm(t)) {
      Functor f = (Functor) RepAppl(t);
      if (f == FunctorDouble) {
	volatile Float dbl;
	volatile Term *t_dbl = (Term *)((void *) &dbl);
	t = TrNode_entry(ans_node);
	ans_node = TrNode_parent(ans_node);
	*t_dbl = t;
#if SIZEOF_DOUBLE == 2 * SIZEOF_INT_P
	t = TrNode_entry(ans_node);
	ans_node = TrNode_parent(ans_node);
	*(t_dbl + 1) = t;
#endif /* SIZEOF_DOUBLE x SIZEOF_INT_P */
	ans_node = TrNode_parent(ans_node);
	t = MkFloatTerm(dbl);
	STACK_CHECK_EXPAND(stack_terms, stack_vars, stack_terms_base);
	STACK_PUSH_UP(t, stack_terms);
      } else if (f == FunctorLongInt) {
	Int li = TrNode_entry(ans_node);
	ans_node = TrNode_parent(ans_node);
	ans_node = TrNode_parent(ans_node);
	t = MkLongIntTerm(li);
	STACK_CHECK_EXPAND(stack_terms, stack_vars, stack_terms_base);
	STACK_PUSH_UP(t, stack_terms);
      } else {
	int f_arity = ArityOfFunctor(f);
	t = Yap_MkApplTerm(f, f_arity, stack_terms);
	stack_terms += f_arity;
	STACK_CHECK_EXPAND(stack_terms, stack_vars, stack_terms_base);
	STACK_PUSH_UP(t, stack_terms);
      }
    }
    t = TrNode_entry(ans_node);
    ans_node = TrNode_parent(ans_node);
  } while (ans_node);

  for (i = subs_arity; i >= 1; i--) {
    CELL *subs_var = (CELL *) *(subs_ptr + i);
    t = STACK_POP_DOWN(stack_terms);
    Bind(subs_var, t);
  }

#ifdef TABLING_ERRORS
  if (stack_terms != (CELL *)Yap_TrailTop)
    TABLING_ERROR_MESSAGE("stack_terms != Yap_TrailTop (load_answer_trie)");
#endif /* TABLING_ERRORS */

  return;
}


void private_completion(sg_fr_ptr sg_fr) {
  /* complete subgoals */
#ifdef LIMIT_TABLING
  sg_fr_ptr aux_sg_fr;
  while (LOCAL_top_sg_fr != sg_fr) {
    aux_sg_fr = LOCAL_top_sg_fr;
    LOCAL_top_sg_fr = SgFr_next(aux_sg_fr);
    mark_as_completed(aux_sg_fr);
    insert_into_global_sg_fr_list(aux_sg_fr);
  }
  aux_sg_fr = LOCAL_top_sg_fr;
  LOCAL_top_sg_fr = SgFr_next(aux_sg_fr);
  mark_as_completed(aux_sg_fr);
  insert_into_global_sg_fr_list(aux_sg_fr);
#else
  while (LOCAL_top_sg_fr != sg_fr) {
    mark_as_completed(LOCAL_top_sg_fr);
    LOCAL_top_sg_fr = SgFr_next(LOCAL_top_sg_fr);
  }
  mark_as_completed(LOCAL_top_sg_fr);
  LOCAL_top_sg_fr = SgFr_next(LOCAL_top_sg_fr);
#endif /* LIMIT_TABLING */

  /* release dependency frames */
  while (EQUAL_OR_YOUNGER_CP(DepFr_cons_cp(LOCAL_top_dep_fr), B)) {  /* never equal if batched scheduling */
    dep_fr_ptr dep_fr = DepFr_next(LOCAL_top_dep_fr);
    FREE_DEPENDENCY_FRAME(LOCAL_top_dep_fr);
    LOCAL_top_dep_fr = dep_fr;
  }

  /* adjust freeze registers */
  adjust_freeze_registers();

  return;
}


void free_subgoal_trie_branch(sg_node_ptr node, int nodes_left, int nodes_extra) {
  if (TrNode_next(node))
    free_subgoal_trie_branch(TrNode_next(node), nodes_left, nodes_extra);

  if (nodes_extra) {
#ifdef TRIE_COMPACT_PAIRS
    if (nodes_extra < 0) {
      Term t = TrNode_entry(node);
      if (IsPairTerm(t)) {
	if (t == CompactPairInit)
	  nodes_extra--;
	else  /* CompactPairEndList / CompactPairEndTerm */
	  nodes_extra++;
      }
    } else 
#endif /* TRIE_COMPACT_PAIRS */
    if (--nodes_extra == 0)
      nodes_left--;
  } else {
    Term t = TrNode_entry(node);
    if (IsVarTerm(t) || IsAtomOrIntTerm(t))
      nodes_left--;
    else if (IsPairTerm(t))
#ifdef TRIE_COMPACT_PAIRS
      /* CompactPairInit */
      nodes_extra = -1;
#else
      nodes_left++;
#endif /* TRIE_COMPACT_PAIRS */
    else if (IsApplTerm(t)) {
      Functor f = (Functor) RepAppl(t);
      if (f == FunctorDouble)
#if SIZEOF_DOUBLE == 2 * SIZEOF_INT_P
	nodes_extra = 2;
#else
        nodes_extra = 1;
#endif /* SIZEOF_DOUBLE x SIZEOF_INT_P */
      else if (f == FunctorLongInt)
	nodes_extra = 1;
      else
	nodes_left += ArityOfFunctor(f) - 1;
    }
  }
  if (nodes_left)
    free_subgoal_trie_branch(TrNode_child(node), nodes_left, nodes_extra);
  else {
    sg_fr_ptr sg_fr;
    ans_node_ptr ans_node;
    sg_fr = (sg_fr_ptr) TrNode_sg_fr(node);
    free_answer_hash_chain(SgFr_hash_chain(sg_fr));
    ans_node = SgFr_answer_trie(sg_fr);
    if (TrNode_child(ans_node))
      free_answer_trie_branch(TrNode_child(ans_node));
    FREE_ANSWER_TRIE_NODE(ans_node);
#ifdef LIMIT_TABLING
    remove_from_global_sg_fr_list(sg_fr);
#endif /* LIMIT_TABLING */
    FREE_SUBGOAL_FRAME(sg_fr);
  }

  FREE_SUBGOAL_TRIE_NODE(node);
  return;
}


void free_answer_trie_branch(ans_node_ptr node) {
#ifdef TABLING_INNER_CUTS
  if (TrNode_child(node) && ! IS_ANSWER_LEAF_NODE(node))
#else
  if (! IS_ANSWER_LEAF_NODE(node))
#endif /* TABLING_INNER_CUTS */
    free_answer_trie_branch(TrNode_child(node));
  if (TrNode_next(node))
    free_answer_trie_branch(TrNode_next(node));
  FREE_ANSWER_TRIE_NODE(node);
  return;
}


void update_answer_trie(sg_fr_ptr sg_fr) {
  ans_node_ptr node;

  free_answer_hash_chain(SgFr_hash_chain(sg_fr));
  SgFr_hash_chain(sg_fr) = NULL;
  node = TrNode_child(SgFr_answer_trie(sg_fr));
  if (node) {
    TrNode_instr(node) -= 1;
#ifdef TABLING_INNER_CUTS
    update_answer_trie_branch(NULL, node);
#else
    update_answer_trie_branch(node);
#endif /* TABLING_INNER_CUTS */
  }
  SgFr_state(sg_fr) += 2;  /* complete --> compiled : complete_in_use --> compiled_in_use */
  return;
}


static struct trie_statistics{
  int show;
  long subgoals;
  long subgoals_incomplete;
  long subgoal_trie_nodes;
  long subgoal_linear_nodes;
  int  subgoal_trie_max_depth;
  int  subgoal_trie_min_depth;
  long answers;
  long answers_yes;
  long answers_no;
  long answers_pruned;
  long answer_trie_nodes;
  long answer_linear_nodes;
  int  answer_trie_max_depth;
  int  answer_trie_min_depth;
} trie_stats;
#define TrStat_show              trie_stats.show
#define TrStat_subgoals          trie_stats.subgoals
#define TrStat_sg_incomplete     trie_stats.subgoals_incomplete
#define TrStat_sg_nodes          trie_stats.subgoal_trie_nodes
#define TrStat_sg_linear_nodes   trie_stats.subgoal_linear_nodes
#define TrStat_sg_max_depth      trie_stats.subgoal_trie_max_depth
#define TrStat_sg_min_depth      trie_stats.subgoal_trie_min_depth
#define TrStat_answers           trie_stats.answers
#define TrStat_answers_yes       trie_stats.answers_yes
#define TrStat_answers_no        trie_stats.answers_no
#define TrStat_ans_pruned        trie_stats.answers_pruned
#define TrStat_ans_nodes         trie_stats.answer_trie_nodes
#define TrStat_ans_linear_nodes  trie_stats.answer_linear_nodes
#define TrStat_ans_max_depth     trie_stats.answer_trie_max_depth
#define TrStat_ans_min_depth     trie_stats.answer_trie_min_depth

#define STR_ARRAY_SIZE  100000
#define ARITY_ARRAY_SIZE 10000
#define SHOW_TABLE(MESG, ARGS...)  if (TrStat_show) fprintf(Yap_stdout, MESG, ##ARGS)


void traverse_table(tab_ent_ptr tab_ent, int show_table) {
  sg_node_ptr sg_node = TrNode_child(TabEnt_subgoal_trie(tab_ent));

  TrStat_show = show_table;
  TrStat_subgoals = 0;
  TrStat_sg_incomplete = 0;
  TrStat_sg_nodes = 1;
  TrStat_sg_linear_nodes = 0;
  TrStat_sg_max_depth = -1;
  TrStat_sg_min_depth = -1;
  TrStat_answers = 0;
  TrStat_answers_yes = 0;
  TrStat_answers_no = 0;
  TrStat_ans_pruned = 0;
  TrStat_ans_nodes = 0;
  TrStat_ans_linear_nodes = 0;
  TrStat_ans_max_depth = -1;
  TrStat_ans_min_depth = -1;
  if (sg_node) {
    if (TabEnt_arity(tab_ent)) {
      char *str = (char *) malloc(sizeof(char) * STR_ARRAY_SIZE);
      int str_index = sprintf(str, "  ?- %s(", AtomName(TabEnt_atom(tab_ent)));
      int *arity = (int *) malloc(sizeof(int) * ARITY_ARRAY_SIZE);
      arity[0] = 1;
      arity[1] = TabEnt_arity(tab_ent);
      traverse_subgoal_trie(sg_node, str, str_index, arity, 1, TRAVERSE_NORMAL);
      free(str);
      free(arity);
    } else {
      sg_fr_ptr sg_fr = (sg_fr_ptr) sg_node;
      TrStat_subgoals++;
      TrStat_sg_linear_nodes = TrStat_sg_min_depth = TrStat_sg_max_depth = 0;
      SHOW_TABLE("  ?- %s.\n", AtomName(TabEnt_atom(tab_ent)));
      TrStat_ans_nodes++;
      TrStat_ans_max_depth = TrStat_ans_min_depth = 0;
      if (SgFr_first_answer(sg_fr) == NULL) {
	if (SgFr_state(sg_fr) < complete) {
	  TrStat_sg_incomplete++;
	  SHOW_TABLE("    ---> INCOMPLETE\n");
	} else {
	  TrStat_answers_no++;
	  SHOW_TABLE("    NO\n");
	}
      } else {  /* SgFr_first_answer(sg_fr) == SgFr_answer_trie(sg_fr) */
	TrStat_answers_yes++;
	TrStat_answers++;
	SHOW_TABLE("    TRUE\n");
      }
    }
  } else
    SHOW_TABLE("  empty\n");
  return;
}


void table_stats(void) {
  fprintf(Yap_stdout, "\n  Subgoal trie structure");
  fprintf(Yap_stdout, "\n    subgoals: %ld", TrStat_subgoals);
  fprintf(Yap_stdout, "\n    subgoals incomplete: %ld", TrStat_sg_incomplete);
  fprintf(Yap_stdout, "\n    nodes: %ld (%ld%c saving)", 
          TrStat_sg_nodes,
	  TrStat_sg_linear_nodes == 0 ? 0 : (TrStat_sg_linear_nodes - TrStat_sg_nodes + 1) * 100 / TrStat_sg_linear_nodes,
	  '%');
  fprintf(Yap_stdout, "\n    average depth: %.2f (%d min - %d max)", 
	  TrStat_subgoals == 0 ? 0 : (float)TrStat_sg_linear_nodes / (float)TrStat_subgoals,
	  TrStat_sg_min_depth < 0 ? 0 : TrStat_sg_min_depth,
	  TrStat_sg_max_depth < 0 ? 0 : TrStat_sg_max_depth);
  fprintf(Yap_stdout, "\n  Answer trie structure");
  fprintf(Yap_stdout, "\n    answers: %ld", TrStat_answers);
  fprintf(Yap_stdout, "\n    yes answers: %ld", TrStat_answers_yes);
  fprintf(Yap_stdout, "\n    no answers: %ld", TrStat_answers_no);
  fprintf(Yap_stdout, "\n    pruned answers: %ld", TrStat_ans_pruned);
  fprintf(Yap_stdout, "\n    nodes: %ld (%ld%c saving)",
	  TrStat_ans_nodes,
	  TrStat_ans_linear_nodes == 0 ? 0 : (TrStat_ans_linear_nodes - TrStat_ans_nodes + TrStat_subgoals) * 100 / TrStat_ans_linear_nodes,
	    '%');
  fprintf(Yap_stdout, "\n    average depth: %.2f (%d min - %d max)",
	  TrStat_answers == 0 ? 0 : (float)TrStat_ans_linear_nodes / (float)TrStat_answers,
	  TrStat_ans_min_depth < 0 ? 0 : TrStat_ans_min_depth,
	  TrStat_ans_max_depth < 0 ? 0 : TrStat_ans_max_depth);
  fprintf(Yap_stdout, "\n  Total memory in use\n    %ld bytes\n",
	  sizeof(struct table_entry) + 
          TrStat_sg_nodes * sizeof(struct subgoal_trie_node) +
	  TrStat_ans_nodes * sizeof(struct answer_trie_node) +
	  TrStat_subgoals * sizeof(struct subgoal_frame));
  return;
}



/* ------------------------- **
**      Local functions      **
** ------------------------- */

#ifdef YAPOR
#ifdef TABLING_INNER_CUTS
static
int update_answer_trie_branch(ans_node_ptr previous_node, ans_node_ptr node) {
  int ltt;
  if (! IS_ANSWER_LEAF_NODE(node)) {
    if (TrNode_child(node)) {
      TrNode_instr(TrNode_child(node)) -= 1;  /* retry --> try */
      update_answer_trie_branch(NULL, TrNode_child(node));
      if (TrNode_child(node))
        goto update_next_trie_branch;
    }
    /* node belonging to a pruned answer */
    if (previous_node) {
      TrNode_next(previous_node) = TrNode_next(node);
      FREE_ANSWER_TRIE_NODE(node);
      if (TrNode_next(previous_node)) {
        return update_answer_trie_branch(previous_node, TrNode_next(previous_node));
      } else {
        TrNode_instr(previous_node) -= 2;  /* retry --> trust : try --> do */
        return 0;
      }
    } else {
      TrNode_child(TrNode_parent(node)) = TrNode_next(node);
      if (TrNode_next(node)) {
        TrNode_instr(TrNode_next(node)) -= 1;  /* retry --> try */
        update_answer_trie_branch(NULL, TrNode_next(node));          
      }
      FREE_ANSWER_TRIE_NODE(node);
      return 0;
    }
  }
update_next_trie_branch:
  if (TrNode_next(node)) {
    ltt = 1 + update_answer_trie_branch(node, TrNode_next(node));
  } else {
    TrNode_instr(node) -= 2;  /* retry --> trust : try --> do */
    ltt = 1;
  }

  TrNode_or_arg(node) = ltt;
  TrNode_instr(node) = Yap_opcode(TrNode_instr(node));
  return ltt;
}
#else
static
int update_answer_trie_branch(ans_node_ptr node) {
  int ltt;
  if (! IS_ANSWER_LEAF_NODE(node)) {
    TrNode_instr(TrNode_child(node)) -= 1;  /* retry --> try */
    update_answer_trie_branch(TrNode_child(node));
  }
  if (TrNode_next(node)) {
    ltt = 1 + update_answer_trie_branch(TrNode_next(node));
  } else {
    TrNode_instr(node) -= 2;  /* retry --> trust : try --> do */
    ltt = 1;
  }
  TrNode_or_arg(node) = ltt;
  TrNode_instr(node) = Yap_opcode(TrNode_instr(node));
  return ltt;
}
#endif /* TABLING_INNER_CUTS */
#else /* TABLING */
static
void update_answer_trie_branch(ans_node_ptr node) {
  if (! IS_ANSWER_LEAF_NODE(node)) {
    TrNode_instr(TrNode_child(node)) -= 1;  /* retry --> try */
    update_answer_trie_branch(TrNode_child(node));
  }
  if (TrNode_next(node)) {
    update_answer_trie_branch(TrNode_next(node));
  } else {
    TrNode_instr(node) -= 2;  /* retry --> trust : try --> do */
  }
  TrNode_instr(node) = Yap_opcode(TrNode_instr(node));
  return;
}
#endif /* YAPOR */


static
void traverse_subgoal_trie(sg_node_ptr sg_node, char *str, int str_index, int *arity, int depth, int mode) {
  Term t;

  /* test if hashing */
  if (IS_SUBGOAL_HASH(sg_node)) {
    sg_node_ptr *bucket, *last_bucket;
    sg_hash_ptr hash;
    int *current_arity = (int *) malloc(sizeof(int) * (arity[0] + 1));
    memcpy(current_arity, arity, sizeof(int) * (arity[0] + 1));
    hash = (sg_hash_ptr) sg_node;
    bucket = Hash_buckets(hash);
    last_bucket = bucket + Hash_num_buckets(hash);
    do {
      if (*bucket) {
        sg_node = *bucket;
        traverse_subgoal_trie(sg_node, str, str_index, arity, depth, mode);
	memcpy(arity, current_arity, sizeof(int) * (current_arity[0] + 1));
#ifdef TRIE_COMPACT_PAIRS
	if (arity[arity[0]] == -2 && str[str_index - 1] != '[')
	  str[str_index - 1] = ',';
#else
	if (arity[arity[0]] == -1)
	  str[str_index - 1] = '|';
#endif /* TRIE_COMPACT_PAIRS */
      }
    } while (++bucket != last_bucket);
    free(current_arity);
    return;
  }

  /* test if sibling node */
  if (TrNode_next(sg_node)) {
    int *current_arity = (int *) malloc(sizeof(int) * (arity[0] + 1));
    memcpy(current_arity, arity, sizeof(int) * (arity[0] + 1));
    traverse_subgoal_trie(TrNode_next(sg_node), str, str_index, arity, depth, mode);
    memcpy(arity, current_arity, sizeof(int) * (current_arity[0] + 1));
    free(current_arity);
#ifdef TRIE_COMPACT_PAIRS
    if (arity[arity[0]] == -2 && str[str_index - 1] != '[')
      str[str_index - 1] = ',';
#else
    if (arity[arity[0]] == -1)
      str[str_index - 1] = '|';
#endif /* TRIE_COMPACT_PAIRS */
  }

  /* test the node type */
  t = TrNode_entry(sg_node);
#if SIZEOF_DOUBLE == 2 * SIZEOF_INT_P
  if (mode == TRAVERSE_FLOAT) {
    arity[0]++;
    arity[arity[0]] = (int) t;
    mode = TRAVERSE_FLOAT2;
  } else if (mode == TRAVERSE_FLOAT2) {
    volatile Float dbl;
    volatile Term *t_dbl = (Term *)((void *) &dbl);
    *t_dbl = t;
    *(t_dbl + 1) = (Term) arity[arity[0]];
    arity[0]--;
#else /* SIZEOF_DOUBLE == SIZEOF_INT_P */
  if (mode == TRAVERSE_FLOAT) {
    volatile Float dbl;
    volatile Term *t_dbl = (Term *)((void *) &dbl);
    *t_dbl = t;
#endif /* SIZEOF_DOUBLE x SIZEOF_INT_P */
    str_index += sprintf(& str[str_index], "%.15g", dbl);
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
    mode = TRAVERSE_NORMAL;
  } else if (mode == TRAVERSE_LONG) {
    Int li = (Int) t;
#if SHORT_INTS
    str_index += sprintf(& str[str_index], "%ld", li);
#else
    str_index += sprintf(& str[str_index], "%d", li);
#endif /* SHORT_INTS */
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
    mode = TRAVERSE_NORMAL;
  } else if (IsVarTerm(t)) {
#if SHORT_INTS
    str_index += sprintf(& str[str_index], "VAR%ld", VarIndexOfTableTerm(t));
#else
    str_index += sprintf(& str[str_index], "VAR%d", VarIndexOfTableTerm(t));
#endif /* SHORT_INTS */
   while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
  } else if (IsIntTerm(t)) {
#if SHORT_INTS
    str_index += sprintf(& str[str_index], "%ld", IntOfTerm(t));
#else
    str_index += sprintf(& str[str_index], "%d", IntOfTerm(t));
#endif /* SHORT_INTS */
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
  } else if (IsAtomTerm(t)) {
#ifndef TRIE_COMPACT_PAIRS
    if (arity[arity[0]] == -1 && t == TermNil) {
      str[str_index - 1] = ']';
      arity[0]--;
    } else
#endif /* TRIE_COMPACT_PAIRS */
      str_index += sprintf(& str[str_index], "%s", AtomName(AtomOfTerm(t)));
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
  } else if (IsPairTerm(t)) {
#ifdef TRIE_COMPACT_PAIRS
    if (t == CompactPairEndList)
      arity[arity[0]] = -1;
    else if (t == CompactPairEndTerm) {
      str[str_index - 1] = '|';
      arity[arity[0]] = -1;
#else
    if (arity[arity[0]] == -1) {
      str[str_index - 1] = ',';
      arity[arity[0]] = -2;
#endif /* TRIE_COMPACT_PAIRS */
    } else {
      str_index += sprintf(& str[str_index], "[");
      arity[0]++;
      arity[arity[0]] = -2;
    }
  } else if (IsApplTerm(t)) {
    Functor f = (Functor) RepAppl(t);
    if (f == FunctorDouble) {
      mode = TRAVERSE_FLOAT;
    } else if (f == FunctorLongInt) {
      mode = TRAVERSE_LONG;
    } else {
      str_index += sprintf(& str[str_index], "%s(", AtomName(NameOfFunctor(f)));
      arity[0]++;
      arity[arity[0]] = ArityOfFunctor(f);
    }
  }

  TrStat_sg_nodes++;
  /* show answers ... */
  if (arity[0] == 0) {
    sg_fr_ptr sg_fr = (sg_fr_ptr) TrNode_child(sg_node);
    str[str_index] = 0;
    TrStat_subgoals++;
    TrStat_sg_linear_nodes+= depth;
    if (TrStat_sg_max_depth < 0) {
      TrStat_sg_min_depth = TrStat_sg_max_depth = depth;
    } else if (depth < TrStat_sg_min_depth) {
      TrStat_sg_min_depth = depth;
    } else if (depth > TrStat_sg_max_depth) {
      TrStat_sg_max_depth = depth;
    }
    SHOW_TABLE("%s.\n", str);
    TrStat_ans_nodes++;
    if (SgFr_first_answer(sg_fr) == NULL) {
      if (TrStat_ans_max_depth < 0)
	TrStat_ans_max_depth = 0;
      TrStat_ans_min_depth = 0;
      if (SgFr_state(sg_fr) < complete) {
	TrStat_sg_incomplete++;
	SHOW_TABLE("    ---> INCOMPLETE\n");
      } else {
	TrStat_answers_no++;
	SHOW_TABLE("    NO\n");
      }
    } else if (SgFr_first_answer(sg_fr) == SgFr_answer_trie(sg_fr)) {
      if (TrStat_ans_max_depth < 0)
	TrStat_ans_max_depth = 0;
      TrStat_ans_min_depth = 0;
      TrStat_answers_yes++;
      TrStat_answers++;
      SHOW_TABLE("    TRUE\n");
    } else {
      arity[0] = 0;
      traverse_answer_trie(TrNode_child(SgFr_answer_trie(sg_fr)), &str[str_index], 0, arity, 0, 1, TRAVERSE_NORMAL);
      if (SgFr_state(sg_fr) < complete) {
	TrStat_sg_incomplete++;
	SHOW_TABLE("    ---> INCOMPLETE\n");
      }
    }
  }

  /* ... or continue with child node */
  else
    traverse_subgoal_trie(TrNode_child(sg_node), str, str_index, arity, depth + 1, mode);

  return;
}


static
void traverse_answer_trie(ans_node_ptr ans_node, char *str, int str_index, int *arity, int var_index, int depth, int mode) {
  Term t;

  /* test if hashing */
  if (IS_ANSWER_HASH(ans_node)) {
    ans_node_ptr *bucket, *last_bucket;
    ans_hash_ptr hash;
    int *current_arity = (int *) malloc(sizeof(int) * (arity[0] + 1));
    memcpy(current_arity, arity, sizeof(int) * (arity[0] + 1));
    hash = (ans_hash_ptr) ans_node;
    bucket = Hash_buckets(hash);
    last_bucket = bucket + Hash_num_buckets(hash);
    do {
      if (*bucket) {
        ans_node = *bucket;
        traverse_answer_trie(ans_node, str, str_index, arity, var_index, depth, mode);
	memcpy(arity, current_arity, sizeof(int) * (current_arity[0] + 1));
#ifdef TRIE_COMPACT_PAIRS
	if (arity[arity[0]] == -2 && str[str_index - 1] != '[')
	  str[str_index - 1] = ',';
#else
	if (arity[arity[0]] == -1)
	  str[str_index - 1] = '|';
#endif /* TRIE_COMPACT_PAIRS */
      }
    } while (++bucket != last_bucket);
    free(current_arity);
    return;
  }

  /* test if sibling node */
  if (TrNode_next(ans_node)) {
    int *current_arity = (int *) malloc(sizeof(int) * (arity[0] + 1));
    memcpy(current_arity, arity, sizeof(int) * (arity[0] + 1));
    traverse_answer_trie(TrNode_next(ans_node), str, str_index, arity, var_index, depth, mode);
    memcpy(arity, current_arity, sizeof(int) * (current_arity[0] + 1));
    free(current_arity);
#ifdef TRIE_COMPACT_PAIRS
    if (arity[arity[0]] == -2 && str[str_index - 1] != '[')
      str[str_index - 1] = ',';
#else
    if (arity[arity[0]] == -1)
      str[str_index - 1] = '|';
#endif /* TRIE_COMPACT_PAIRS */
  }

  /* print VAR when starting a term */
  if (arity[0] == 0 && mode == TRAVERSE_NORMAL) {
    str_index += sprintf(& str[str_index], "    VAR%d: ", var_index);
    var_index++;
  }

  /* test the node type */
  t = TrNode_entry(ans_node);
  if (mode == TRAVERSE_FLOAT) {
#if SIZEOF_DOUBLE == 2 * SIZEOF_INT_P
    arity[0]++;
    arity[arity[0]] = (int) t;
    mode = TRAVERSE_FLOAT2;
  } else if (mode == TRAVERSE_FLOAT2) {
    volatile Float dbl;
    volatile Term *t_dbl = (Term *)((void *) &dbl);
    *t_dbl = t;
    *(t_dbl + 1) = (Term) arity[arity[0]];
    arity[0]--;
#else /* SIZEOF_DOUBLE == SIZEOF_INT_P */
    volatile Float dbl;
    volatile Term *t_dbl = (Term *)((void *) &dbl);
    *t_dbl = t;
#endif /* SIZEOF_DOUBLE x SIZEOF_INT_P */
    str_index += sprintf(& str[str_index], "%.15g", dbl);
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
    mode = TRAVERSE_FLOAT_END;
  } else if (mode == TRAVERSE_FLOAT_END) {
    mode = TRAVERSE_NORMAL;
  } else if (mode == TRAVERSE_LONG) {
    Int li = (Int) t;
#if SHORT_INTS
    str_index += sprintf(& str[str_index], "%ld", li);
#else
    str_index += sprintf(& str[str_index], "%d", li);
#endif /* SHORT_INTS */
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
    mode = TRAVERSE_LONG_END;
  } else if (mode == TRAVERSE_LONG_END) {
    mode = TRAVERSE_NORMAL;
  } else if (IsVarTerm(t)) {
#if SHORT_INTS
    str_index += sprintf(& str[str_index], "ANSVAR%ld", VarIndexOfTableTerm(t));
#else
    str_index += sprintf(& str[str_index], "ANSVAR%d", VarIndexOfTableTerm(t));
#endif /* SHORT_INTS */
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
  } else if (IsIntTerm(t)) {
#if SHORT_INTS
    str_index += sprintf(& str[str_index], "%ld", IntOfTerm(t));
#else
    str_index += sprintf(& str[str_index], "%d", IntOfTerm(t));
#endif /* SHORT_INTS */
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
  } else if (IsAtomTerm(t)) {
#ifndef TRIE_COMPACT_PAIRS
    if (arity[arity[0]] == -1 && t == TermNil) {
      str[str_index - 1] = ']';
      arity[0]--;
    } else
#endif /* TRIE_COMPACT_PAIRS */
      str_index += sprintf(& str[str_index], "%s", AtomName(AtomOfTerm(t)));
    while (arity[0]) {
      if (arity[arity[0]] > 0) {
	arity[arity[0]]--;
	if (arity[arity[0]] == 0) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      } else {
	if (arity[arity[0]] == -2) {
#ifdef TRIE_COMPACT_PAIRS
	  str_index += sprintf(& str[str_index], ",");
#else
	  str_index += sprintf(& str[str_index], "|");
	  arity[arity[0]] = -1;
#endif /* TRIE_COMPACT_PAIRS */
	  break;
	} else {
	  str_index += sprintf(& str[str_index], "]");
	  arity[0]--;
	}
      }
    }
  } else if (IsPairTerm(t)) {
#ifdef TRIE_COMPACT_PAIRS
    if (t == CompactPairEndList)
      arity[arity[0]] = -1;
    else if (t == CompactPairEndTerm) {
      str[str_index - 1] = '|';
      arity[arity[0]] = -1;
#else
    if (arity[arity[0]] == -1) {
      str[str_index - 1] = ',';
      arity[arity[0]] = -2;
#endif /* TRIE_COMPACT_PAIRS */
    } else {
      str_index += sprintf(& str[str_index], "[");
      arity[0]++;
      arity[arity[0]] = -2;
    }
  } else if (IsApplTerm(t)) {
    Functor f = (Functor) RepAppl(t);
    if (f == FunctorDouble) {
      mode = TRAVERSE_FLOAT;
    } else if (f == FunctorLongInt) {
      mode = TRAVERSE_LONG;
    } else {
      str_index += sprintf(& str[str_index], "%s(", AtomName(NameOfFunctor(f)));
      arity[0]++;
      arity[arity[0]] = ArityOfFunctor(f);
    }
  }

  TrStat_ans_nodes++;
  /* show answer .... */
  if (IS_ANSWER_LEAF_NODE(ans_node)) {
    str[str_index] = 0;
    SHOW_TABLE("%s\n", str);
    TrStat_answers++;
    TrStat_ans_linear_nodes+= depth;
    if (TrStat_ans_max_depth < 0)
      TrStat_ans_min_depth = TrStat_ans_max_depth = depth;
    else if (depth < TrStat_ans_min_depth)
      TrStat_ans_min_depth = depth;
    else if (depth > TrStat_ans_max_depth)
      TrStat_ans_max_depth = depth;
  }

#ifdef TABLING_INNER_CUTS
  /* ... or continue with pruned node */
  else if (TrNode_child(ans_node) == NULL)
    TrStat_ans_pruned++;
#endif /* TABLING_INNER_CUTS */

  /* ... or continue with child node */
  else
    traverse_answer_trie(TrNode_child(ans_node), str, str_index, arity, var_index, depth + 1, mode);

  return;
}
#endif /* TABLING */