yap-6.3/library/tries/core_tries.c

/*********************************************
  File:     core_tries.c
  Author:   Ricardo Rocha
  Comments: Tries core module for Yap Prolog
  version:  $ID$
*********************************************/



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

#include <YapInterface.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "core_tries.h"



/* -------------------------- */
/*      Local Procedures      */
/* -------------------------- */

static TrNode   put_entry(TrNode node, YAP_Term entry);
static TrNode   check_entry(TrNode node, YAP_Term entry);
static YAP_Term get_entry(TrNode node, YAP_Term *stack_list, TrNode *cur_node);
static void     remove_entry(TrNode node);
static void     remove_child_nodes(TrNode node);
static TrNode   copy_child_nodes(TrNode parent_dest, TrNode node_source);
static void     traverse_and_add(TrNode parent_dest, TrNode parent_source);
static void     traverse_and_join(TrNode parent_dest, TrNode parent_source);
static void     traverse_and_intersect(TrNode parent_dest, TrNode parent_source);
static YAP_Int  traverse_and_count_common_entries(TrNode parent1, TrNode parent2);
static YAP_Int  traverse_and_count_entries(TrNode node);
static void     traverse_and_get_usage(TrNode node, YAP_Int depth);
static void     traverse_and_save(TrNode node, FILE *file, int float_block);
static void     traverse_and_load(TrNode parent, FILE *file);
static void     traverse_and_print(TrNode node, int *arity, char *str, int str_index, int mode);

static YAP_Term trie_to_list(TrNode node);
static YAP_Term trie_to_list_node(TrNode node);
static YAP_Term trie_to_list_floats(TrNode node);


/* -------------------------- */
/*       Local Variables      */
/* -------------------------- */

static TrEngine CURRENT_TRIE_ENGINE;
static YAP_Int USAGE_ENTRIES, USAGE_NODES, USAGE_VIRTUAL_NODES;
static YAP_Int CURRENT_AUXILIARY_TERM_STACK_SIZE, CURRENT_TRIE_MODE, CURRENT_LOAD_VERSION, CURRENT_DEPTH, CURRENT_INDEX;
static YAP_Term *AUXILIARY_TERM_STACK;
static YAP_Term *stack_args, *stack_args_base, *stack_vars, *stack_vars_base;
static YAP_Functor FunctorComma;
static void (*DATA_SAVE_FUNCTION)(TrNode, FILE *);
static void (*DATA_LOAD_FUNCTION)(TrNode, YAP_Int, FILE *);
static void (*DATA_PRINT_FUNCTION)(TrNode);
static void (*DATA_ADD_FUNCTION)(TrNode, TrNode);
static void (*DATA_COPY_FUNCTION)(TrNode, TrNode);
static void (*DATA_DESTRUCT_FUNCTION)(TrNode);

static YAP_Int TRIE_DISABLE_HASH_TABLE = 0;


/* -------------------------- */
/*     Inline Procedures      */
/* -------------------------- */

static inline
TrNode trie_node_check_insert(TrNode parent, YAP_Term t) {
  TrNode child;

  CURRENT_DEPTH++;
  child = TrNode_child(parent);
  if (child == NULL) {
    new_trie_node(child, t, parent, NULL, NULL, NULL);
    TrNode_child(parent) = child;
  } else if (IS_HASH_NODE(child)) {
    TrHash hash;
    TrNode *bucket;
    int count;
    hash = (TrHash) child;
    bucket = TrHash_bucket(hash, HASH_TERM(t, TrHash_seed(hash)));
    child = *bucket;
    count = 0;
    while (child) {
      if ((TrNode_entry(child) == t) || (((TrNode_entry(child) == PairEndTermTag) || (TrNode_entry(child) == PairEndEmptyTag)) && ((CURRENT_TRIE_MODE & TRIE_MODE_MINIMAL) == TRIE_MODE_MINIMAL)))
        return child;
      count++;
      child = TrNode_next(child);
    } while (child);
    TrHash_num_nodes(hash)++;
    new_trie_node(child, t, parent, NULL, *bucket, AS_TR_NODE_NEXT(bucket));
    if (*bucket)
      TrNode_previous(*bucket) = child;
    *bucket = child;
    if (count > MAX_NODES_PER_BUCKET && TrHash_num_nodes(hash) > TrHash_num_buckets(hash)) {
      /* expand trie hash */
      TrNode chain, next, *first_bucket, *new_bucket;
      int seed;
      first_bucket = TrHash_buckets(hash);
      bucket = first_bucket + TrHash_num_buckets(hash);
      TrHash_num_buckets(hash) *= 2;
      new_hash_buckets(hash, TrHash_num_buckets(hash)); 
      seed = TrHash_num_buckets(hash) - 1;
      do {
        if (*--bucket) {
          chain = *bucket;
          do {
            new_bucket = TrHash_bucket(hash, HASH_TERM(TrNode_entry(chain), seed));
            next = TrNode_next(chain);
            TrNode_next(chain) = *new_bucket;
            TrNode_previous(chain) = AS_TR_NODE_NEXT(bucket);
            if (*new_bucket)
              TrNode_previous(*new_bucket) = chain;
            *new_bucket = chain;
            chain = next;
          } while (chain);
        }
      } while (bucket != first_bucket);
      free_hash_buckets(first_bucket, TrHash_num_buckets(hash) / 2);
    }
  } else {
    int count = 0;
    do {
      if ((TrNode_entry(child) == t) || (((TrNode_entry(child) == PairEndTermTag) || (TrNode_entry(child) == PairEndEmptyTag)) && ((CURRENT_TRIE_MODE & TRIE_MODE_MINIMAL) == TRIE_MODE_MINIMAL)))
        return child;
      count++;
      child = TrNode_next(child);
    } while (child);
    new_trie_node(child, t, parent, NULL, TrNode_child(parent), NULL);
    TrNode_previous(TrNode_child(parent)) = child;
    if ((++count > MAX_NODES_PER_TRIE_LEVEL) && (TRIE_DISABLE_HASH_TABLE == 0)) {
      /* alloc a new trie hash */
      TrHash hash;
      TrNode chain, next, *bucket;
      new_trie_hash(hash, count, BASE_HASH_BUCKETS);
      chain = child;
      do {
        bucket = TrHash_bucket(hash, HASH_TERM(TrNode_entry(chain), BASE_HASH_BUCKETS - 1));
        next = TrNode_next(chain);
        TrNode_next(chain) = *bucket;
        TrNode_previous(chain) = AS_TR_NODE_NEXT(bucket);
        if (*bucket)
          TrNode_previous(*bucket) = chain;
        *bucket = chain;
        chain = next;
      } while (chain);
      TrNode_child(parent) = (TrNode) hash;
    } else
      TrNode_child(parent) = child;
  }
  return child;
}


static inline
TrNode trie_node_insert(TrNode parent, YAP_Term t, TrHash hash) {
  TrNode child;

  CURRENT_DEPTH++;
  if (hash) {
    /* is trie hash */
    TrNode *bucket;
    TrHash_num_nodes(hash)++;
    bucket = TrHash_bucket(hash, HASH_TERM(t, TrHash_seed(hash)));
    new_trie_node(child, t, parent, NULL, *bucket, AS_TR_NODE_NEXT(bucket));
    if (*bucket)
      TrNode_previous(*bucket) = child;
    *bucket = child;
  } else {
    new_trie_node(child, t, parent, NULL, TrNode_child(parent), NULL);
    if (TrNode_child(parent))
      TrNode_previous(TrNode_child(parent)) = child;
    TrNode_child(parent) = child;
  }
  return child;
}


static inline
TrNode trie_node_check(TrNode parent, YAP_Term t) {
  TrNode child;

  child = TrNode_child(parent);
  if (IS_HASH_NODE(child)) {
    TrHash hash;
    TrNode *bucket;
    hash = (TrHash) child;
    bucket = TrHash_bucket(hash, HASH_TERM(t, TrHash_seed(hash)));
    child = *bucket;
    if (!child)
      return NULL;
  }
  do {
    if (TrNode_entry(child) == t)
      return child;
    child = TrNode_next(child);
  } while (child);
  return NULL;
}


static inline
YAP_Term trie_to_list_create_simple(const char *atom_name, TrNode node) {
  YAP_Functor f = YAP_MkFunctor(YAP_LookupAtom(atom_name), 1);
  YAP_Term child = trie_to_list(TrNode_child(node));  

  return YAP_MkApplTerm(f, 1, &child);
}


static inline
YAP_Term trie_to_list_create_simple_end(const char *atom_name, TrNode node) {
  YAP_Atom atom = YAP_LookupAtom(atom_name);
  
  if (IS_LEAF_TRIE_NODE(node)) {
    return YAP_MkAtomTerm(atom);
  } else {
    YAP_Functor f = YAP_MkFunctor(atom, 1);
    YAP_Term child = trie_to_list(TrNode_child(node));    
    return YAP_MkApplTerm(f, 1, &child);
  }
}


static inline
YAP_Term trie_to_list_create_two(const char *atom_name, TrNode node, YAP_Term operand) {
  YAP_Atom atom = YAP_LookupAtom(atom_name);
  
  if(IS_LEAF_TRIE_NODE(node)) {
    YAP_Functor f = YAP_MkFunctor(atom, 1);
    return YAP_MkApplTerm(f, 1, &operand);
  } else {
    YAP_Functor f = YAP_MkFunctor(atom, 2);
    YAP_Term args[2] = {
      operand, trie_to_list(TrNode_child(node))
    };
    return YAP_MkApplTerm(f, 2, args);
  }
}


/* -------------------------- */
/*            API             */     
/* -------------------------- */

inline
TrEngine core_trie_init_module(void) {
  static int init_once = 1;
  TrEngine engine;

  if (init_once) {
    new_struct(AUXILIARY_TERM_STACK, YAP_Term, BASE_AUXILIARY_TERM_STACK_SIZE * sizeof(YAP_Term));
    CURRENT_AUXILIARY_TERM_STACK_SIZE = BASE_AUXILIARY_TERM_STACK_SIZE;
    CURRENT_TRIE_MODE = TRIE_MODE_STANDARD;
    FunctorComma = YAP_MkFunctor(YAP_LookupAtom(","), 2);
    init_once = 0;
  }
  new_trie_engine(engine);
  return engine;
}


inline
TrNode core_trie_open(TrEngine engine) {
  TrNode node;

  CURRENT_TRIE_ENGINE = engine;
  new_trie_node(node, 0, NULL, NULL, TrEngine_trie(engine), AS_TR_NODE_NEXT(&TrEngine_trie(engine)));
  if (TrEngine_trie(engine))
    TrNode_previous(TrEngine_trie(engine)) = node;
  TrEngine_trie(engine) = node;
  INCREMENT_TRIES(CURRENT_TRIE_ENGINE);
  return node;
}


inline
void core_trie_close(TrEngine engine, TrNode node, void (*destruct_function)(TrNode)) {
  CURRENT_TRIE_ENGINE = engine;
  DATA_DESTRUCT_FUNCTION = destruct_function;
  if (TrNode_child(node))
    remove_child_nodes(TrNode_child(node));
  if (TrNode_next(node)) {
    TrNode_previous(TrNode_next(node)) = TrNode_previous(node);
    TrNode_next(TrNode_previous(node)) = TrNode_next(node);
  } else
    TrNode_next(TrNode_previous(node)) = NULL;
  free_trie_node(node);  
  DECREMENT_TRIES(CURRENT_TRIE_ENGINE);
  return;
}


inline
void core_trie_close_all(TrEngine engine, void (*destruct_function)(TrNode)) {
  while (TrEngine_trie(engine))
    core_trie_close(engine, TrEngine_trie(engine), destruct_function);
  return;
}


inline
void core_trie_set_mode(YAP_Int mode) {
  CURRENT_TRIE_MODE = mode;
  return;
}


inline
YAP_Int core_trie_get_mode(void) {
  return CURRENT_TRIE_MODE;
}


inline
TrNode core_trie_put_entry(TrEngine engine, TrNode node, YAP_Term entry, YAP_Int *depth) {
  CURRENT_TRIE_ENGINE = engine;
  CURRENT_DEPTH = 0;
  stack_args_base = stack_args = AUXILIARY_TERM_STACK;
  stack_vars_base = stack_vars = AUXILIARY_TERM_STACK + CURRENT_AUXILIARY_TERM_STACK_SIZE - 1;
  node = put_entry(node, entry);
  if (!IS_LEAF_TRIE_NODE(node)) {
    MARK_AS_LEAF_TRIE_NODE(node);
    INCREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
  }
  /* reset var terms */
  while (STACK_NOT_EMPTY(stack_vars++, stack_vars_base)) {
    (void) POP_DOWN(stack_vars);
    *((YAP_Term *)*stack_vars) = *stack_vars;
  }
  if (depth)
    *depth = CURRENT_DEPTH;
  return node;
}


inline
TrNode core_trie_check_entry(TrNode node, YAP_Term entry) {
  if (!TrNode_child(node))
    return NULL;
  stack_args_base = stack_args = AUXILIARY_TERM_STACK;
  stack_vars_base = stack_vars = AUXILIARY_TERM_STACK + CURRENT_AUXILIARY_TERM_STACK_SIZE - 1;
  node = check_entry(node, entry);
  /* reset var terms */
  while (STACK_NOT_EMPTY(stack_vars++, stack_vars_base)) {
    (void) POP_DOWN(stack_vars);
    *((YAP_Term *)*stack_vars) = *stack_vars;
  }
  return node;
}


inline
YAP_Term core_trie_get_entry(TrNode node) {
  CURRENT_INDEX = -1;
  stack_vars_base = stack_vars = AUXILIARY_TERM_STACK;
  stack_args_base = stack_args = AUXILIARY_TERM_STACK + CURRENT_AUXILIARY_TERM_STACK_SIZE - 1;
  return get_entry(node, stack_args, &node);
}


inline
void core_trie_remove_entry(TrEngine engine, TrNode node, void (*destruct_function)(TrNode)) {
  CURRENT_TRIE_ENGINE = engine;
  DATA_DESTRUCT_FUNCTION = destruct_function;
  if (DATA_DESTRUCT_FUNCTION)
    (*DATA_DESTRUCT_FUNCTION)(node);
  DECREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
  remove_entry(node);
  return;
}


inline
void core_trie_remove_subtree(TrEngine engine, TrNode node, void (*destruct_function)(TrNode)) {
  TrNode parent;

  CURRENT_TRIE_ENGINE = engine;
  DATA_DESTRUCT_FUNCTION = destruct_function;
  parent = TrNode_parent(node);
  remove_child_nodes(TrNode_child(parent));
  remove_entry(parent);
  return;
}


inline
void core_trie_add(TrNode node_dest, TrNode node_source, void (*add_function)(TrNode, TrNode)) {
  DATA_ADD_FUNCTION = add_function;
  if (TrNode_child(node_dest) && TrNode_child(node_source))
    traverse_and_add(node_dest, node_source);
  return;
}


inline
void core_trie_join(TrEngine engine, TrNode node_dest, TrNode node_source, void (*add_function)(TrNode, TrNode), void (*copy_function)(TrNode, TrNode)) {
  CURRENT_TRIE_ENGINE = engine;
  DATA_ADD_FUNCTION = add_function;
  DATA_COPY_FUNCTION = copy_function;
  if (TrNode_child(node_dest)) {
    if (TrNode_child(node_source))
      traverse_and_join(node_dest, node_source);
  } else if (TrNode_child(node_source))
    TrNode_child(node_dest) = copy_child_nodes(node_dest, TrNode_child(node_source));
  return;
}


inline
void core_trie_intersect(TrEngine engine, TrNode node_dest, TrNode node_source, void (*add_function)(TrNode, TrNode), void (*destruct_function)(TrNode)) {
  CURRENT_TRIE_ENGINE = engine;
  DATA_ADD_FUNCTION = add_function;
  DATA_DESTRUCT_FUNCTION = destruct_function;
  if (TrNode_child(node_dest)) {
    if (TrNode_child(node_source))
      traverse_and_intersect(node_dest, node_source);
    else {
      remove_child_nodes(TrNode_child(node_dest));
      TrNode_child(node_dest) = NULL;
    }
  }
  return;
}


inline
YAP_Int core_trie_count_join(TrNode node1, TrNode node2) {
  YAP_Int count = 0;

  if (TrNode_child(node1)) {
    count += traverse_and_count_entries(TrNode_child(node1));
    if (TrNode_child(node2)) {
      count += traverse_and_count_entries(TrNode_child(node2));
      count -= traverse_and_count_common_entries(node1, node2);
    }
  } else if (TrNode_child(node2))
    count += traverse_and_count_entries(TrNode_child(node2));
  return count;
}


inline
YAP_Int core_trie_count_intersect(TrNode node1, TrNode node2) {
  YAP_Int count = 0;

  if (TrNode_child(node1))
    if (TrNode_child(node2))
      count = traverse_and_count_common_entries(node1, node2);
  return count;
}


inline
void core_trie_save(TrNode node, FILE *file, void (*save_function)(TrNode, FILE *)) {
  CURRENT_INDEX = -1;
  DATA_SAVE_FUNCTION = save_function;
  if (TrNode_child(node)) {
    fprintf(file, "BEGIN_TRIE_v2 ");
    traverse_and_save(TrNode_child(node), file, 0);
    fprintf(file, "END_TRIE_v2");
  }
  return;
}


inline
TrNode core_trie_load(TrEngine engine, FILE *file, void (*load_function)(TrNode, YAP_Int, FILE *)) {
  TrNode node;
  char version[15];
  fpos_t curpos;
  int n;

  n = fscanf(file, "%14s", version);
  if (fgetpos(file, &curpos))
    return NULL;

  if (!strcmp(version, "BEGIN_TRIE_v2")) {
    fseek(file, -11, SEEK_END);
    n = fscanf(file, "%s", version);
    if (strcmp(version, "END_TRIE_v2")) {
      fprintf(stderr, "******************************************\n");
      fprintf(stderr, "  Tries core module: trie file corrupted\n");
      fprintf(stderr, "******************************************\n");  
      return NULL;
    }
    if (fsetpos(file, &curpos))
      return NULL;
    CURRENT_LOAD_VERSION = 2;
  } else if (!strcmp(version, "BEGIN_TRIE")) {
    fseek(file, -8, SEEK_END);
    n = fscanf(file, "%s", version);
    if (strcmp(version, "END_TRIE")) {
      fprintf(stderr, "******************************************\n");
      fprintf(stderr, "  Tries core module: trie file corrupted\n");
      fprintf(stderr, "******************************************\n");  
      return NULL;
    }
    if (fsetpos(file, &curpos))
      return NULL;
    CURRENT_LOAD_VERSION = 1;
  } else {
    fprintf(stderr, "****************************************\n");
    fprintf(stderr, "  Tries core module: invalid trie file\n");
    fprintf(stderr, "****************************************\n");  
    return NULL;
  }
  CURRENT_TRIE_ENGINE = engine;
  CURRENT_INDEX = -1;
  CURRENT_DEPTH = 0;
  DATA_LOAD_FUNCTION = load_function;
  node = core_trie_open(engine);
  traverse_and_load(node, file);
  return node;
}


inline
void core_trie_stats(TrEngine engine, YAP_Int *memory, YAP_Int *tries, YAP_Int *entries, YAP_Int *nodes) {
  *memory = TrEngine_memory(engine);
  *tries = TrEngine_tries(engine);
  *entries = TrEngine_entries(engine);
  *nodes = TrEngine_nodes(engine);
  return;
}


inline
void core_trie_max_stats(TrEngine engine, YAP_Int *memory, YAP_Int *tries, YAP_Int *entries, YAP_Int *nodes) {
  *memory = TrEngine_memory_max(engine);
  *tries = TrEngine_tries_max(engine);
  *entries = TrEngine_entries_max(engine);
  *nodes = TrEngine_nodes_max(engine);
  return;
}


inline
void core_trie_usage(TrNode node, YAP_Int *entries, YAP_Int *nodes, YAP_Int *virtual_nodes) {
  USAGE_ENTRIES = 0;
  USAGE_NODES = 0;
  USAGE_VIRTUAL_NODES = 0;
  if (TrNode_child(node))
    traverse_and_get_usage(TrNode_child(node), 0);
  *entries = USAGE_ENTRIES;
  *nodes = USAGE_NODES;
  *virtual_nodes = USAGE_VIRTUAL_NODES;
  return;
}


inline
void core_trie_print(TrNode node, void (*print_function)(TrNode)) {
  DATA_PRINT_FUNCTION = print_function;
  if (TrNode_child(node)) {
    int arity[1000];
    char str[10000];
    arity[0] = 0;
    traverse_and_print(TrNode_child(node), arity, str, 0, TRIE_PRINT_NORMAL);
  } else
    fprintf(stdout, "(empty)\n");
  return;
}


inline
void core_disable_hash_table(void) {
  TRIE_DISABLE_HASH_TABLE = 1;
}


inline
void core_enable_hash_table(void) {
  TRIE_DISABLE_HASH_TABLE = 0;
}


inline
YAP_Term core_trie_to_list(TrNode node) {
  TrNode root = TrNode_child(node);
  
  if (root)
    return trie_to_list(root);
  else
    return YAP_MkAtomTerm(YAP_LookupAtom("empty"));
}


/* -------------------------- */
/*      Local Procedures      */
/* -------------------------- */

static
TrNode put_entry(TrNode node, YAP_Term entry) {
  YAP_Term t = YAP_Deref(entry);
  if (YAP_IsVarTerm(t)) {
    if (IsTrieVar(t, stack_vars, stack_vars_base)) {
      node = trie_node_check_insert(node, MkTrieVar((stack_vars_base - 1 - (YAP_Term *)t) / 2));
    } else {
      node = trie_node_check_insert(node, MkTrieVar((stack_vars_base - stack_vars) / 2));
      PUSH_UP(stack_vars, t, stack_args);
      *((YAP_Term *)t) = (YAP_Term)stack_vars;
      PUSH_UP(stack_vars, stack_vars, stack_args);
    }
  } else if (YAP_IsAtomTerm(t)) {
    node = trie_node_check_insert(node, t);
  } else if (YAP_IsIntTerm(t)) {
    node = trie_node_check_insert(node, t);
  } else if (YAP_IsFloatTerm(t)) {
    volatile double f;
    volatile YAP_Term *p;
    f = YAP_FloatOfTerm(t);
    p = (YAP_Term *)((void *) &f); /* to avoid gcc warning */
    node = trie_node_check_insert(node, FloatInitTag);
    node = trie_node_check_insert(node, *p);
#ifdef TAG_LOW_BITS_32
    node = trie_node_check_insert(node, *(p + 1));
#endif /* TAG_LOW_BITS_32 */
    node = trie_node_check_insert(node, FloatEndTag);
  } else if (YAP_IsPairTerm(t)) {
    node = trie_node_check_insert(node, PairInitTag);
    if ((CURRENT_TRIE_MODE & TRIE_MODE_REVERSE) == TRIE_MODE_STANDARD) {
      do {
        node = put_entry(node, YAP_HeadOfTerm(t));
        t = YAP_Deref(YAP_TailOfTerm(t));
      } while (YAP_IsPairTerm(t));
      if (t == YAP_TermNil()) {
        node = trie_node_check_insert(node, PairEndEmptyTag);
      } else {
        node = put_entry(node, t);
        node = trie_node_check_insert(node, PairEndTermTag);
      }
    } else if (CURRENT_TRIE_MODE & TRIE_MODE_REVERSE) { /* TRIE_MODE_REVERSE */
      YAP_Term *stack_list = stack_args;
      do {
        PUSH_DOWN(stack_args, YAP_HeadOfTerm(t), stack_vars);
        t = YAP_Deref(YAP_TailOfTerm(t));
      } while (YAP_IsPairTerm(t));
      if (t == YAP_TermNil()) {
        while (STACK_NOT_EMPTY(stack_args, stack_list))
          node = put_entry(node, POP_UP(stack_args));
        node = trie_node_check_insert(node, PairEndEmptyTag);
      } else {
        PUSH_DOWN(stack_args, t, stack_vars);
        while (STACK_NOT_EMPTY(stack_args, stack_list))
          node = put_entry(node, POP_UP(stack_args));
        node = trie_node_check_insert(node, PairEndTermTag);
      }
    }
  } else if (YAP_IsApplTerm(t)) {
    YAP_Functor f = YAP_FunctorOfTerm(t);
    if (f == FunctorComma) {
      node = trie_node_check_insert(node, CommaInitTag);
      do {
        node = put_entry(node, YAP_ArgOfTerm(1, t));
        t = YAP_Deref(YAP_ArgOfTerm(2, t));
      } while (YAP_IsApplTerm(t) && YAP_FunctorOfTerm(t) == FunctorComma);
      node = put_entry(node, t);
      node = trie_node_check_insert(node, CommaEndTag);
    } else {
      int i;
      node = trie_node_check_insert(node, ApplTag | ((YAP_Term) f));
      for (i = 1; i <= YAP_ArityOfFunctor(f); i++)
        node = put_entry(node, YAP_ArgOfTerm(i, t));
    }
  } else {
    fprintf(stderr, "***************************************\n");
    fprintf(stderr, "  Tries core module: unknown type tag\n");
    fprintf(stderr, "***************************************\n");
  }
  
  return node;
}


static
TrNode check_entry(TrNode node, YAP_Term entry) {
  YAP_Term t = YAP_Deref(entry);
  if (YAP_IsVarTerm(t)) {
    if (IsTrieVar(t, stack_vars, stack_vars_base)) {
      if (!(node = trie_node_check(node, MkTrieVar((stack_vars_base - 1 - (YAP_Term *)t) / 2))))
        return NULL;
    } else {
      if (!(node = trie_node_check(node, MkTrieVar((stack_vars_base - stack_vars) / 2))))
        return NULL;
      PUSH_UP(stack_vars, t, stack_args);
      *((YAP_Term *)t) = (YAP_Term)stack_vars;
      PUSH_UP(stack_vars, stack_vars, stack_args);
    }
  } else if (YAP_IsAtomTerm(t)) {
    if (!(node = trie_node_check(node, t)))
      return NULL;
  } else if (YAP_IsIntTerm(t)) {
    if (!(node = trie_node_check(node, t)))
      return NULL;
  } else if (YAP_IsFloatTerm(t)) {
    volatile double f;
    volatile YAP_Term *p;
    f = YAP_FloatOfTerm(t);
    p = (YAP_Term *)((void *) &f); /* to avoid gcc warning */
    if (!(node = trie_node_check(node, FloatInitTag)))
      return NULL;
    if (!(node = trie_node_check(node, *p)))
      return NULL;
#ifdef TAG_LOW_BITS_32
    if (!(node = trie_node_check(node, *(p + 1))))
      return NULL;
#endif /* TAG_LOW_BITS_32 */
    if (!(node = trie_node_check(node, FloatEndTag)))
      return NULL;
  } else if (YAP_IsPairTerm(t)) {
    if (!(node = trie_node_check(node, PairInitTag)))
      return NULL;
    if ((CURRENT_TRIE_MODE & TRIE_MODE_REVERSE) == TRIE_MODE_STANDARD) {
      do {
        if (!(node = check_entry(node, YAP_HeadOfTerm(t))))
          return NULL;
        t = YAP_Deref(YAP_TailOfTerm(t));
      } while (YAP_IsPairTerm(t));
      if (t == YAP_TermNil()) {
        if (!(node = trie_node_check(node, PairEndEmptyTag)))
          return NULL;
      } else {
        if (!(node = check_entry(node, t)))
          return NULL;
        if (!(node = trie_node_check(node, PairEndTermTag)))
          return NULL;
      }
    } else if (CURRENT_TRIE_MODE & TRIE_MODE_REVERSE) { /* TRIE_MODE_REVERSE */
      YAP_Term *stack_list = stack_args;
      do {
        PUSH_DOWN(stack_args, YAP_HeadOfTerm(t), stack_vars);
        t = YAP_Deref(YAP_TailOfTerm(t));
      } while (YAP_IsPairTerm(t));
      if (t == YAP_TermNil()) {
        while (STACK_NOT_EMPTY(stack_args, stack_list))
          if (!(node = check_entry(node, POP_UP(stack_args))))
            return NULL;
        if (!(node = trie_node_check(node, PairEndEmptyTag)))
          return NULL;
      } else {
        PUSH_DOWN(stack_args, t, stack_vars);
        while (STACK_NOT_EMPTY(stack_args, stack_list))
          if (!(node = check_entry(node, POP_UP(stack_args))))
            return NULL;
        if (!(node = trie_node_check(node, PairEndTermTag)))
          return NULL;
      }
    }
  } else if (YAP_IsApplTerm(t)) {
    YAP_Functor f = YAP_FunctorOfTerm(t);
    if (f == FunctorComma) {
      if (!(node = trie_node_check(node, CommaInitTag)))
        return NULL;
      do {
        if (!(node = check_entry(node, YAP_ArgOfTerm(1, t))))
          return NULL;
        t = YAP_Deref(YAP_ArgOfTerm(2, t));
      } while (YAP_IsApplTerm(t) && YAP_FunctorOfTerm(t) == FunctorComma);
      if (!(node = check_entry(node, t)))
        return NULL;
      if (!(node = trie_node_check(node, CommaEndTag)))
        return NULL;
    } else {
      int i;
      if (!(node = trie_node_check(node, ApplTag | ((YAP_Term) f))))
        return NULL;
      for (i = 1; i <= YAP_ArityOfFunctor(f); i++)
        if (!(node = check_entry(node, YAP_ArgOfTerm(i, t))))
          return NULL;
    }
  } else {
    fprintf(stderr, "***************************************\n");
    fprintf(stderr, "  Tries core module: unknown type tag\n");
    fprintf(stderr, "***************************************\n");
  }
  
  return node;
}


static
YAP_Term get_entry(TrNode node, YAP_Term *stack_mark, TrNode *cur_node) {
  YAP_Term t = (YAP_Term) &t;
  while (TrNode_parent(node)) {
    t = TrNode_entry(node);
    if (YAP_IsVarTerm(t)) {
      int index = TrieVarIndex(t);
      if (index > CURRENT_INDEX) {
        int i;
        stack_vars = &stack_vars_base[index + 1];
        if (stack_vars > stack_args + 1) {
          fprintf(stderr, "**************************************\n");
          fprintf(stderr, "  Tries core module: term stack full\n");
          fprintf(stderr, "**************************************\n");
        }
        for (i = index; i > CURRENT_INDEX; i--)
          stack_vars_base[i] = 0;
        CURRENT_INDEX = index;
      }
      if (stack_vars_base[index]) {
        t = stack_vars_base[index];
      } else {
        t = YAP_MkVarTerm();
        stack_vars_base[index] = t;
      }
      PUSH_UP(stack_args, t, stack_vars);
    } else if (YAP_IsAtomTerm(t)) {
      PUSH_UP(stack_args, t, stack_vars);
    } else if (YAP_IsIntTerm(t)) {
      PUSH_UP(stack_args, t, stack_vars);
    } else if (YAP_IsPairTerm(t)) {
      if (t == PairInitTag) {
        YAP_Term t2;
        if ((CURRENT_TRIE_MODE & TRIE_MODE_REVERSE) == TRIE_MODE_STANDARD) {
          YAP_Term *stack_aux = stack_mark;
          t = *stack_aux--;
          while (STACK_NOT_EMPTY(stack_aux, stack_args)) {
            t2 = *stack_aux--;
            t = YAP_MkPairTerm(t2, t);
          }
        } else if (CURRENT_TRIE_MODE & TRIE_MODE_REVERSE) { /* TRIE_MODE_REVERSE */
          YAP_Term *stack_aux = stack_mark;
          t = *stack_aux;
          if (t == YAP_TermNil())
            stack_aux--;
          else
            t = POP_DOWN(stack_args);
          while (STACK_NOT_EMPTY(stack_args, stack_aux)) {
            t2 = POP_DOWN(stack_args);
            t = YAP_MkPairTerm(t2, t);
          }
        }
        stack_args = stack_mark;
        *cur_node = node;
        return t;
      } else if (t == PairEndEmptyTag) {
        t = YAP_TermNil();
        PUSH_UP(stack_args, t, stack_vars);
        node = TrNode_parent(node);
        t = get_entry(node, &stack_args[1], &node);
        PUSH_UP(stack_args, t, stack_vars);
      } else if (t == PairEndTermTag) {
        node = TrNode_parent(node);
        t = get_entry(node, stack_args, &node);
        PUSH_UP(stack_args, t, stack_vars);
      } else if (t == CommaEndTag) {
        node = TrNode_parent(node);
        t = get_entry(node, stack_args, &node);
        PUSH_UP(stack_args, t, stack_vars);
      } else if (t == CommaInitTag) {
        YAP_Term *stack_aux = stack_mark;
        stack_aux--;
        while (STACK_NOT_EMPTY(stack_aux, stack_args)) {
          t = YAP_MkApplTerm(FunctorComma, 2, stack_aux);
          *stack_aux = t;
          stack_aux--;
        }
        stack_args = stack_mark;
        *cur_node = node;
        return t;
      } else if (t == FloatEndTag) {
        volatile double f;
        volatile YAP_Term *p;
        p = (YAP_Term *)((void *) &f); /* to avoid gcc warning */
#ifdef TAG_LOW_BITS_32
        node = TrNode_parent(node);
        *(p + 1) = TrNode_entry(node);
#endif /* TAG_LOW_BITS_32 */
        node = TrNode_parent(node);
        *p = TrNode_entry(node);
        node = TrNode_parent(node); /* ignore FloatInitTag */
        t = YAP_MkFloatTerm(f);
        PUSH_UP(stack_args, t, stack_vars);
      } else if (t == FloatInitTag) {
      }
    } else if (ApplTag & t) {
      YAP_Functor f = (YAP_Functor)(~ApplTag & t);
      int arity = YAP_ArityOfFunctor(f);
      t = YAP_MkApplTerm(f, arity, &stack_args[1]);
      stack_args += arity;
      PUSH_UP(stack_args, t, stack_vars);
    } else {
      fprintf(stderr, "***************************************\n");
      fprintf(stderr, "  Tries core module: unknown type tag\n");
      fprintf(stderr, "***************************************\n");
    }
    node = TrNode_parent(node);
  }
  *cur_node = node;
  return t;
}


static
void remove_entry(TrNode node) {
  TrNode parent = TrNode_parent(node);
  while (parent) {
    if (TrNode_previous(node)) {
      if (IS_HASH_NODE(TrNode_child(parent))) {
	TrHash hash = (TrHash) TrNode_child(parent);
	TrHash_num_nodes(hash)--;
	if (TrHash_num_nodes(hash)) {
	  if (TrNode_next(node)) {
	    TrNode_next(TrNode_previous(node)) = TrNode_next(node);
	    TrNode_previous(TrNode_next(node)) = TrNode_previous(node);
	  } else {
	    TrNode_next(TrNode_previous(node)) = NULL;
	  }
	  free_trie_node(node);
	  return;
	}
	free_hash_buckets(TrHash_buckets(hash), TrHash_num_buckets(hash));
	free_trie_hash(hash);
      } else {
	if (TrNode_next(node)) {
	  TrNode_next(TrNode_previous(node)) = TrNode_next(node);
	  TrNode_previous(TrNode_next(node)) = TrNode_previous(node);
	} else {
	  TrNode_next(TrNode_previous(node)) = NULL;
	}
	free_trie_node(node);
	return;
      }
    } else if (TrNode_next(node)) {
      TrNode_child(parent) = TrNode_next(node);
      TrNode_previous(TrNode_next(node)) = NULL;
      free_trie_node(node);
      return;
    }
    free_trie_node(node);
    node = parent;
    parent = TrNode_parent(node);
  }
  TrNode_child(node) = NULL;
  return;
}


static
void remove_child_nodes(TrNode node) {
  if (IS_HASH_NODE(node)) {
    TrNode *first_bucket, *bucket;
    TrHash hash = (TrHash) node;
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    do {
      if (*--bucket)
	remove_child_nodes(*bucket);
    } while (bucket != first_bucket);
    free_hash_buckets(first_bucket, TrHash_num_buckets(hash));
    free_trie_hash(hash);
    return;
  }
  if (TrNode_next(node))
    remove_child_nodes(TrNode_next(node));
  if (!IS_LEAF_TRIE_NODE(node))
    remove_child_nodes(TrNode_child(node));
  else {
    if (DATA_DESTRUCT_FUNCTION)
      (*DATA_DESTRUCT_FUNCTION)(node);
    DECREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
  }
  free_trie_node(node);
  return;
}


static
TrNode copy_child_nodes(TrNode parent_dest, TrNode child_source) {
  TrNode child_dest, next_dest;

  if (IS_HASH_NODE(child_source)) {
    TrNode *bucket_dest, *first_bucket_source, *bucket_source;
    TrHash hash_dest, hash_source;
    hash_source = (TrHash) child_source;
    first_bucket_source = TrHash_buckets(hash_source);
    bucket_source = first_bucket_source + TrHash_num_buckets(hash_source);
    new_trie_hash(hash_dest, TrHash_num_nodes(hash_source), TrHash_num_buckets(hash_source));
    bucket_dest = TrHash_buckets(hash_dest) + TrHash_num_buckets(hash_dest);
    do {
      bucket_dest--;
      if (*--bucket_source) {
	*bucket_dest = copy_child_nodes(parent_dest, *bucket_source);
	TrNode_previous(*bucket_dest) = AS_TR_NODE_NEXT(bucket_dest);
      } else
	*bucket_dest = NULL;
    } while (bucket_source != first_bucket_source);
    return (TrNode) hash_dest;
  }

  if (TrNode_next(child_source))
    next_dest = copy_child_nodes(parent_dest, TrNode_next(child_source));
  else
    next_dest = NULL;
  new_trie_node(child_dest, TrNode_entry(child_source), parent_dest, NULL, next_dest, NULL);
  if (next_dest)
    TrNode_previous(next_dest) = child_dest;
  if (IS_LEAF_TRIE_NODE(child_source)) {
    MARK_AS_LEAF_TRIE_NODE(child_dest);
    INCREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
    if (DATA_COPY_FUNCTION)
      (*DATA_COPY_FUNCTION)(child_dest, child_source);
  } else
    TrNode_child(child_dest) = copy_child_nodes(child_dest, TrNode_child(child_source));
  return child_dest;
}


static
void traverse_and_add(TrNode parent_dest, TrNode parent_source) {
  TrNode child_dest, child_source;

  /* parent_source is not a leaf node */
  child_source = TrNode_child(parent_source);
  if (IS_HASH_NODE(child_source)) {
    TrNode *first_bucket_source, *bucket_source;
    TrHash hash_source;
    hash_source = (TrHash) child_source;
    first_bucket_source = TrHash_buckets(hash_source);
    bucket_source = first_bucket_source + TrHash_num_buckets(hash_source);
    do {
      child_source = *--bucket_source;
      while (child_source) {
	/* parent_dest is not a leaf node */
	child_dest = trie_node_check(parent_dest, TrNode_entry(child_source));
	if (child_dest) {
	  if (IS_LEAF_TRIE_NODE(child_dest)) {
	    /* child_source is a leaf node */
	    if (DATA_ADD_FUNCTION)
	      (*DATA_ADD_FUNCTION)(child_dest, child_source);
	  } else
	    /* child_dest and child_source are not leaf nodes */
	    traverse_and_add(child_dest, child_source);
	}
	child_source = TrNode_next(child_source);
      }
    } while (bucket_source != first_bucket_source);
    return;
  }
  while (child_source) {
    /* parent_dest is not a leaf node */
    child_dest = trie_node_check(parent_dest, TrNode_entry(child_source));
    if (child_dest) {
      if (IS_LEAF_TRIE_NODE(child_dest)) {
	/* child_source is a leaf node */
	if (DATA_ADD_FUNCTION)
	  (*DATA_ADD_FUNCTION)(child_dest, child_source);
      } else
	/* child_dest and child_source are not leaf nodes */
	traverse_and_add(child_dest, child_source);
    }
    child_source = TrNode_next(child_source);
  }
  return;
}


static
void traverse_and_join(TrNode parent_dest, TrNode parent_source) {
  TrNode child_dest, child_source;

  /* parent_source is not a leaf node */
  child_source = TrNode_child(parent_source);
  if (IS_HASH_NODE(child_source)) {
    TrNode *first_bucket_source, *bucket_source;
    TrHash hash_source;
    hash_source = (TrHash) child_source;
    first_bucket_source = TrHash_buckets(hash_source);
    bucket_source = first_bucket_source + TrHash_num_buckets(hash_source);
    do {
      child_source = *--bucket_source;
      while (child_source) {
	/* parent_dest is not a leaf node */
	child_dest = trie_node_check(parent_dest, TrNode_entry(child_source));
	if (child_dest) {
	  if (IS_LEAF_TRIE_NODE(child_dest)) {
	    /* child_source is a leaf node */
	    if (DATA_ADD_FUNCTION)
	      (*DATA_ADD_FUNCTION)(child_dest, child_source);
	  } else
	    /* child_dest and child_source are not leaf nodes */
	    traverse_and_join(child_dest, child_source);
	} else {
	  child_dest = trie_node_check_insert(parent_dest, TrNode_entry(child_source));
	  if (IS_LEAF_TRIE_NODE(child_source)) {
	    MARK_AS_LEAF_TRIE_NODE(child_dest);
	    INCREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
	    if (DATA_COPY_FUNCTION)
	      (*DATA_COPY_FUNCTION)(child_dest, child_source);
	  } else
            TrNode_child(child_dest) = copy_child_nodes(child_dest, TrNode_child(child_source));
	}
	child_source = TrNode_next(child_source);
      }
    } while (bucket_source != first_bucket_source);
    return;
  }
  while (child_source) {
    /* parent_dest is not a leaf node */
    child_dest = trie_node_check(parent_dest, TrNode_entry(child_source));
    if (child_dest) {
      if (IS_LEAF_TRIE_NODE(child_dest)) {
	/* child_source is a leaf node */
	if (DATA_ADD_FUNCTION)
	  (*DATA_ADD_FUNCTION)(child_dest, child_source);
      } else
	/* child_dest and child_source are not leaf nodes */
	traverse_and_join(child_dest, child_source);
    } else {
      child_dest = trie_node_check_insert(parent_dest, TrNode_entry(child_source));
      if (IS_LEAF_TRIE_NODE(child_source)) {
	MARK_AS_LEAF_TRIE_NODE(child_dest);
	INCREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
	if (DATA_COPY_FUNCTION)
	  (*DATA_COPY_FUNCTION)(child_dest, child_source);
      } else
        TrNode_child(child_dest) = copy_child_nodes(child_dest, TrNode_child(child_source));
    }
    child_source = TrNode_next(child_source);
  }
  return;
}


static
void traverse_and_intersect(TrNode parent_dest, TrNode parent_source) {
  TrNode child_dest, child_source, child_next;

  /* parent_dest is not a leaf node */
  child_dest = TrNode_child(parent_dest);
  if (IS_HASH_NODE(child_dest)) {
    TrNode *first_bucket_dest, *bucket_dest;
    TrHash hash_dest;
    hash_dest = (TrHash) child_dest;
    first_bucket_dest = TrHash_buckets(hash_dest);
    bucket_dest = first_bucket_dest + TrHash_num_buckets(hash_dest);
    do {
      child_dest = *--bucket_dest;
      while (child_dest) {
	child_next = TrNode_next(child_dest);
	/* parent_source is not a leaf node */
	child_source = trie_node_check(parent_source, TrNode_entry(child_dest));
	if (child_source) {
	  if (IS_LEAF_TRIE_NODE(child_dest)) {
	    /* child_source is a leaf node */
	    if (DATA_ADD_FUNCTION)
	      (*DATA_ADD_FUNCTION)(child_dest, child_source);
	  } else
	    /* child_dest and child_source are not leaf nodes */
	    traverse_and_intersect(child_dest, child_source);
	} else {
	  if (IS_LEAF_TRIE_NODE(child_dest)) {
	    if (DATA_DESTRUCT_FUNCTION)
	      (*DATA_DESTRUCT_FUNCTION)(child_dest);
	    DECREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
	  } else
	    remove_child_nodes(TrNode_child(child_dest));
	  remove_entry(child_dest);
	}
	child_dest = child_next;
      }
    } while (bucket_dest != first_bucket_dest);
    return;
  }
  while (child_dest) {
    child_next = TrNode_next(child_dest);
    /* parent_source is not a leaf node */
    child_source = trie_node_check(parent_source, TrNode_entry(child_dest));
    if (child_source) {
      if (IS_LEAF_TRIE_NODE(child_dest)) {
	/* child_source is a leaf node */
	if (DATA_ADD_FUNCTION)
	  (*DATA_ADD_FUNCTION)(child_dest, child_source);
      } else
	/* child_dest and child_source are not leaf nodes */
	traverse_and_intersect(child_dest, child_source);
    } else {
      if (IS_LEAF_TRIE_NODE(child_dest)) {
	if (DATA_DESTRUCT_FUNCTION)
	  (*DATA_DESTRUCT_FUNCTION)(child_dest);
	DECREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
      } else
	remove_child_nodes(TrNode_child(child_dest));
      remove_entry(child_dest);
    }
    child_dest = child_next;
  }
  return;
}


static
YAP_Int traverse_and_count_common_entries(TrNode parent1, TrNode parent2) {
  TrNode child1, child2;
  YAP_Int count = 0;

  /* parent1 is not a leaf node */
  child1 = TrNode_child(parent1);
  if (IS_HASH_NODE(child1)) {
    TrNode *first_bucket, *bucket;
    TrHash hash;
    hash = (TrHash) child1;
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    do {
      child1 = *--bucket;
      while (child1) {
	/* parent2 is not a leaf node */
	child2 = trie_node_check(parent2, TrNode_entry(child1));
	if (child2) {
	  if (IS_LEAF_TRIE_NODE(child1))
	    /* child2 is a leaf node */
	    count++;
	  else
	    /* child1 and child2 are not leaf nodes */
	    count += traverse_and_count_common_entries(child1, child2);
	}
	child1 = TrNode_next(child1);
      }
    } while (bucket != first_bucket);
    return count;
  }
  while (child1) {
    /* parent2 is not a leaf node */
    child2 = trie_node_check(parent2, TrNode_entry(child1));
    if (child2) {
      if (IS_LEAF_TRIE_NODE(child1))
	/* child2 is a leaf node */
	count++;
      else
	/* child1 and child2 are not leaf nodes */
	count += traverse_and_count_common_entries(child1, child2);
    }
    child1 = TrNode_next(child1);
  }
  return count;
}


static
YAP_Int traverse_and_count_entries(TrNode node) {
  YAP_Int count = 0;

  if (IS_HASH_NODE(node)) {
    TrNode *first_bucket, *bucket;
    TrHash hash;
    hash = (TrHash) node;
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    do {
      if (*--bucket) {
        node = *bucket;
        count += traverse_and_count_entries(node);
      }
    } while (bucket != first_bucket);
    return count;
  }

  if (TrNode_next(node))
    count += traverse_and_count_entries(TrNode_next(node));
  if (!IS_LEAF_TRIE_NODE(node))
    count += traverse_and_count_entries(TrNode_child(node));
  else
    count++;
  return count;
}


static
void traverse_and_get_usage(TrNode node, YAP_Int depth) {
  if (IS_HASH_NODE(node)) {
    TrNode *first_bucket, *bucket;
    TrHash hash;
    hash = (TrHash) node;
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    do {
      if (*--bucket) {
        node = *bucket;
        traverse_and_get_usage(node, depth);
      }
    } while (bucket != first_bucket);
    return;
  }

  USAGE_NODES++;
  if (TrNode_next(node))
    traverse_and_get_usage(TrNode_next(node), depth);
  depth++;
  if (!IS_LEAF_TRIE_NODE(node)) {
    traverse_and_get_usage(TrNode_child(node), depth);
  } else {
    USAGE_ENTRIES++;
    USAGE_VIRTUAL_NODES+= depth;
  }
  return;
}


static
void traverse_and_save(TrNode node, FILE *file, int float_block) {
  YAP_Term t;

  if (IS_HASH_NODE(node)) {
    TrNode *first_bucket, *bucket;
    TrHash hash;
    hash = (TrHash) node;
    fprintf(file, "%lu %d ", HASH_SAVE_MARK, TrHash_num_buckets(hash));
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    do {
      if (*--bucket) {
        node = *bucket;
	traverse_and_save(node, file, float_block);
      }
    } while (bucket != first_bucket);
    return;
  }

  if (TrNode_next(node))
    traverse_and_save(TrNode_next(node), file, float_block);

  t = TrNode_entry(node);
  if (float_block) {
    float_block--;
    fprintf(file, "%lu %lu ", FLOAT_SAVE_MARK, t);
  } else if (YAP_IsPairTerm(t)) {
    if (t == FloatInitTag) {
#ifdef TAG_LOW_BITS_32
      float_block++;
#endif /* TAG_LOW_BITS_32 */
      float_block ++;
    }
    fprintf(file, "%lu ", t);
  } else if (YAP_IsVarTerm(t) || YAP_IsIntTerm(t))
    fprintf(file, "%lu ", t);
  else {
    int index;
    for (index = 0; index <= CURRENT_INDEX; index++)
      if (AUXILIARY_TERM_STACK[index] == t)
	break;
    if (index > CURRENT_INDEX) {
      CURRENT_INDEX = index;
      if (CURRENT_INDEX == CURRENT_AUXILIARY_TERM_STACK_SIZE)
	expand_auxiliary_term_stack();
      AUXILIARY_TERM_STACK[CURRENT_INDEX] = t;
      if (YAP_IsAtomTerm(t))
	  fprintf(file, "%lu %d %s%c ", ATOM_SAVE_MARK, index, YAP_AtomName(YAP_AtomOfTerm(t)), '\0');
      else  /* (ApplTag & t) */
	fprintf(file, "%lu %d %s %d ", FUNCTOR_SAVE_MARK, index,
		YAP_AtomName(YAP_NameOfFunctor((YAP_Functor)(~ApplTag & t))),
		YAP_ArityOfFunctor((YAP_Functor)(~ApplTag & t)));
    } else
      if (YAP_IsAtomTerm(t))
	fprintf(file, "%lu %d ", ATOM_SAVE_MARK, index);
      else
	fprintf(file, "%lu %d ", FUNCTOR_SAVE_MARK, index);
  }
  if (IS_LEAF_TRIE_NODE(node)) {
    fprintf(file, "- ");
    if (DATA_SAVE_FUNCTION)
      (*DATA_SAVE_FUNCTION)(node, file);
  }
  else {
    traverse_and_save(TrNode_child(node), file, float_block);
    fprintf(file, "- ");
  }
  return;
}


static
void traverse_and_load(TrNode parent, FILE *file) {
  TrHash hash = NULL;
  YAP_Term t;
  int n;

  if (!fscanf(file, "%lu", &t)) {
    MARK_AS_LEAF_TRIE_NODE(parent);
    INCREMENT_ENTRIES(CURRENT_TRIE_ENGINE);
    if (DATA_LOAD_FUNCTION)
      (*DATA_LOAD_FUNCTION)(parent, CURRENT_DEPTH, file);
    CURRENT_DEPTH--;
    return;
  }
  if (t == HASH_SAVE_MARK) {
    /* alloc a new trie hash */
    int num_buckets;
    n = fscanf(file, "%d", &num_buckets);
    new_trie_hash(hash, 0, num_buckets);
    TrNode_child(parent) = (TrNode) hash;
    n = fscanf(file, "%lu", &t);
  }
  do {
    TrNode child;
    if (t == ATOM_SAVE_MARK) {
      int index;
      n = fscanf(file, "%d", &index);
      if (index > CURRENT_INDEX) {
	char atom[1000];
	if (CURRENT_LOAD_VERSION == 2) {
	  char *ptr, ch;
	  ptr = atom;
	  fgetc(file);  /* skip the first empty space */
	  while ((ch = fgetc(file)))
	    *ptr++ = ch;
	  *ptr = '\0';
	} else if (CURRENT_LOAD_VERSION == 1) {
	  n = fscanf(file, "%s", atom);
	}
	CURRENT_INDEX = index;
	if (CURRENT_INDEX == CURRENT_AUXILIARY_TERM_STACK_SIZE)
	  expand_auxiliary_term_stack();
	AUXILIARY_TERM_STACK[CURRENT_INDEX] = YAP_MkAtomTerm(YAP_LookupAtom(atom));
      }
      t = AUXILIARY_TERM_STACK[index];
    } else if (t == FUNCTOR_SAVE_MARK) {
      int index;
      n = fscanf(file, "%d", &index);
      if (index > CURRENT_INDEX) {
	char atom[1000];
	int arity;
	n = fscanf(file, "%s %d", atom, &arity);
	CURRENT_INDEX = index;
	if (CURRENT_INDEX == CURRENT_AUXILIARY_TERM_STACK_SIZE)
	  expand_auxiliary_term_stack();
	AUXILIARY_TERM_STACK[CURRENT_INDEX] = ApplTag | ((YAP_Term) YAP_MkFunctor(YAP_LookupAtom(atom), arity));
      }
      t = AUXILIARY_TERM_STACK[index];
    } else if (t == FLOAT_SAVE_MARK)
      n = fscanf(file, "%lu", &t);
    child = trie_node_insert(parent, t, hash);
    traverse_and_load(child, file);
  } while (fscanf(file, "%lu", &t));
  CURRENT_DEPTH--;
  return;
}


static
void traverse_and_print(TrNode node, int *arity, char *str, int str_index, int mode) {
  YAP_Term t;
  int last_pair_mark = -arity[arity[0]];

  if (IS_HASH_NODE(node)) {
    int *current_arity = (int *) malloc(sizeof(int) * (arity[0] + 1));
    TrNode *first_bucket, *bucket;
    TrHash hash;
    hash = (TrHash) node;
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    memcpy(current_arity, arity, sizeof(int) * (arity[0] + 1));
    do {
      if (*--bucket) {
        node = *bucket;
        traverse_and_print(node, arity, str, str_index, mode);
	memcpy(arity, current_arity, sizeof(int) * (current_arity[0] + 1));
	if (mode != TRIE_PRINT_FLOAT2 && arity[arity[0]] < 0) {
	  /* restore possible PairEndEmptyTag/PairEndTermTag/CommaEndTag side-effect */
	  if (str[str_index - 1] != '[')
	    str[str_index - 1] = ',';
	  /* restore possible PairEndTermTag side-effect */
	  if (str[last_pair_mark] == '|')
	    str[last_pair_mark] = ',';
	}
      }
    } while (bucket != first_bucket);
    free(current_arity);
    return;
  }

  if (TrNode_next(node)) {
    int *current_arity = (int *) malloc(sizeof(int) * (arity[0] + 1));
    memcpy(current_arity, arity, sizeof(int) * (arity[0] + 1));
    traverse_and_print(TrNode_next(node), arity, str, str_index, mode);
    memcpy(arity, current_arity, sizeof(int) * (current_arity[0] + 1));
    if (mode != TRIE_PRINT_FLOAT2 && arity[arity[0]] < 0) {
      /* restore possible PairEndEmptyTag/PairEndTermTag/CommaEndTag side-effect */
      if (str[str_index - 1] != '[')
	str[str_index - 1] = ',';
      /* restore possible PairEndTermTag side-effect */
      if (str[last_pair_mark] == '|')
	str[last_pair_mark] = ',';
    }
    free(current_arity);
  }

  /* update position for possible PairEndTermTag side-effect */
  if (mode != TRIE_PRINT_FLOAT2 && arity[arity[0]] < 0 && str_index > 1)
    arity[arity[0]] = -str_index + 1;

  t = TrNode_entry(node);
  if (mode == TRIE_PRINT_FLOAT) {
#ifdef TAG_LOW_BITS_32
    arity[arity[0]] = (YAP_Int) t;
    mode = TRIE_PRINT_FLOAT2;
  } else if (mode == TRIE_PRINT_FLOAT2) {
    volatile double f;
    volatile YAP_Term *p;
    p = (YAP_Term *)((void *) &f); /* to avoid gcc warning */
    *(p + 1) = t;
    *p = (YAP_Term) arity[arity[0]];
    arity[arity[0]] = -1;
#else /* TAG_64BITS */
    volatile double f;
    volatile YAP_Term *p;
    p = (YAP_Term *)((void *) &f); /* to avoid gcc warning */
    *p = t;
#endif /* TAG_SCHEME */
    str_index += sprintf(& str[str_index], "%.15g", f);
    mode = TRIE_PRINT_FLOAT_END;
  } else if (mode == TRIE_PRINT_FLOAT_END) {
    arity[0]--;
    while (arity[0]) {
      if (arity[arity[0]] == 1) {
	str_index += sprintf(& str[str_index], ")");
	arity[0]--;
      } else {
	if (arity[arity[0]] > 1)
	  arity[arity[0]]--;
	str_index += sprintf(& str[str_index], ",");
	break;
      }
    }
    mode = TRIE_PRINT_NORMAL;
  } else if (YAP_IsVarTerm(t)) {
    str_index += sprintf(& str[str_index], "VAR%ld", TrieVarIndex(t));
    while (arity[0]) {
      if (arity[arity[0]] == 1) {
	str_index += sprintf(& str[str_index], ")");
	arity[0]--;
      } else {
	if (arity[arity[0]] > 1)
	  arity[arity[0]]--;
	str_index += sprintf(& str[str_index], ",");
	break;
      }
    }
  } else if (YAP_IsAtomTerm(t)) {
    str_index += sprintf(& str[str_index], "%s", YAP_AtomName(YAP_AtomOfTerm(t)));
    while (arity[0]) {
      if (arity[arity[0]] == 1) {
	str_index += sprintf(& str[str_index], ")");
	arity[0]--;
      } else {
	if (arity[arity[0]] > 1)
	  arity[arity[0]]--;
	str_index += sprintf(& str[str_index], ",");
	break;
      }
    }
  } else if (YAP_IsIntTerm(t)) {
    str_index += sprintf(& str[str_index], "%ld", YAP_IntOfTerm(t));
    while (arity[0]) {
      if (arity[arity[0]] == 1) {
	str_index += sprintf(& str[str_index], ")");
	arity[0]--;
      } else {
	if (arity[arity[0]] > 1)
	  arity[arity[0]]--;
	str_index += sprintf(& str[str_index], ",");
	break;
      }
    }
  } else if (YAP_IsPairTerm(t)) {
    if (t == FloatInitTag) {
      mode = TRIE_PRINT_FLOAT;
      arity[0]++;
      arity[arity[0]] = -1;
    } else if (t == PairInitTag) {
      str_index += sprintf(& str[str_index], "[");
      arity[0]++;
      arity[arity[0]] = -1;
    } else if (t == CommaInitTag) {
      str_index += sprintf(& str[str_index], "(");
      arity[0]++;
      arity[arity[0]] = -1;
    } else {
      if (t == PairEndEmptyTag)
	str[str_index - 1] = ']';
      else if (t == PairEndTermTag) {
	str[last_pair_mark] = '|';
	str[str_index - 1] = ']';
      } else /*   (t == CommaEndTag)   */
	str[str_index - 1] = ')';
      arity[0]--;
      while (arity[0]) {
	if (arity[arity[0]] == 1) {
	  str_index += sprintf(& str[str_index], ")");
	  arity[0]--;
	} else {
	  if (arity[arity[0]] > 1)
	    arity[arity[0]]--;
	  str_index += sprintf(& str[str_index], ",");
	  break;
	}
      }
    }
  } else if (ApplTag & t) {
    str_index += sprintf(& str[str_index], "%s(", YAP_AtomName(YAP_NameOfFunctor((YAP_Functor)(~ApplTag & t))));
    arity[0]++;
    arity[arity[0]] = YAP_ArityOfFunctor((YAP_Functor)(~ApplTag & t));
  } else {
    fprintf(stderr, "***************************************\n");
    fprintf(stderr, "  Tries core module: unknown type tag\n");
    fprintf(stderr, "***************************************\n");
  }

  if (arity[0]) {
    traverse_and_print(TrNode_child(node), arity, str, str_index, mode);
  } else {
    str[str_index] = 0;
    fprintf(stdout, "%s\n", str);
    if (DATA_PRINT_FUNCTION)
      (*DATA_PRINT_FUNCTION)(node);
  }
  return;
}


static
YAP_Term trie_to_list(TrNode node) {
  YAP_Term tail = YAP_MkAtomTerm(YAP_LookupAtom("[]"));

#define CONSUME_NODE_LIST                                  \
  do {                                                     \
    /* add node result to list */                          \
    tail = YAP_MkPairTerm(trie_to_list_node(node), tail);  \
  } while((node = TrNode_next(node)));
  
  if (IS_HASH_NODE(node)) {
    TrNode *first_bucket, *bucket;
    TrHash hash = (TrHash) node;
    
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    
    /* iterate through valid hash positions and consume each list */
    do {
      if (*--bucket) {
        node = *bucket;
        CONSUME_NODE_LIST;
      }
    } while (bucket != first_bucket);
  } else {
    CONSUME_NODE_LIST;
  }  
#undef CONSUME_NODE_LIST

  /* return list of trie options at this level */
  return tail;
}


static
YAP_Term trie_to_list_node(TrNode node) {
  YAP_Term t = TrNode_entry(node);
  
  if(YAP_IsIntTerm(t) || YAP_IsAtomTerm(t)) {
    return trie_to_list_create_two(YAP_IsIntTerm(t) ? "int" : "atom", node, t);
  } else if (YAP_IsVarTerm(t)) {
    int index = TrieVarIndex(t);
    YAP_Term index_term = YAP_MkIntTerm((YAP_Int)index);
    return trie_to_list_create_two("var", node, index_term);
  } else if (YAP_IsPairTerm(t)) {
    if(t == FloatInitTag) {
      node = TrNode_child(node); /* consume FloatInitTag */      
      YAP_Functor f = YAP_MkFunctor(YAP_LookupAtom("floats"), 1);
      YAP_Term child = trie_to_list_floats(node);
      return YAP_MkApplTerm(f, 1, &child);
    } else if(t == PairInitTag) {
      return trie_to_list_create_simple("list", node);
    } else if (t == PairEndEmptyTag) {
      return trie_to_list_create_simple_end("endlist", node);
    } else if (t == CommaInitTag) {
      return trie_to_list_create_simple("comma", node);
    } else if (t == CommaEndTag) {
      return trie_to_list_create_simple_end("endcomma", node);
    }
  } else if (ApplTag & t) {
    YAP_Functor f = (YAP_Functor)(~ApplTag & t);
    int arity = YAP_ArityOfFunctor(f);
    YAP_Functor new_f = YAP_MkFunctor(YAP_LookupAtom("functor"), 3);
    YAP_Term args[3] = {
      YAP_MkAtomTerm(YAP_NameOfFunctor(f)),
      YAP_MkIntTerm((YAP_Int)arity),
      trie_to_list(TrNode_child(node))
    };
    return YAP_MkApplTerm(new_f, 3, args);
  }
  fprintf(stderr, "***************************************\n");
  fprintf(stderr, "  Tries core module: unknown type tag\n");
  fprintf(stderr, "***************************************\n");
  
  return YAP_MkAtomTerm(YAP_LookupAtom("fail"));
}


#define PUSH_NEW_FLOAT_TERM(val)                                                     \
        result = YAP_MkPairTerm(                                                     \
        trie_to_list_create_two("float", TrNode_child(node), YAP_MkFloatTerm(val)),  \
        result);


#ifdef TAG_LOW_BITS_32
static inline
YAP_Term trie_to_list_floats_tag_low_32(YAP_Term result, TrNode node, volatile YAP_Term **p, volatile double *f) {
  if(IS_HASH_NODE(node)) {
    TrNode *first_bucket, *bucket;
    TrHash hash = (TrHash) node;
    
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    
    do {
      if(*--bucket) {
        node = *bucket;
        
        do {
          *(*p + 1) = TrNode_entry(node);
          PUSH_NEW_FLOAT_TERM(*f);
        } while((node = TrNode_next(node)));
      }
    } while (bucket != first_bucket);
  } else {
    do {
      *(*p + 1) = TrNode_entry(node);
      PUSH_NEW_FLOAT_TERM(*f);
    } while((node = TrNode_next(node)));
  }
  
  return result;
}
#endif /* TAG_LOW_BITS_32 */


static
YAP_Term trie_to_list_floats(TrNode node) {
  volatile double f;
  volatile YAP_Term *p;
  YAP_Term result = YAP_MkAtomTerm(YAP_LookupAtom("[]"));

  p = (YAP_Term *)((void *) &f); /* to avoid gcc warning */
  if (IS_HASH_NODE(node)) {
    TrNode *first_bucket, *bucket;
    TrHash hash = (TrHash) node;    
    first_bucket = TrHash_buckets(hash);
    bucket = first_bucket + TrHash_num_buckets(hash);
    do {
      if (*--bucket) {
        node = *bucket;
        do {
          *p = TrNode_entry(node);
#ifdef TAG_LOW_BITS_32
          result = trie_to_list_floats_tag_low_32(result, TrNode_child(node), &p, &f);
#else
          PUSH_NEW_FLOAT_TERM(f);
#endif /* TAG_LOW_BITS_32 */
        } while((node = TrNode_next(node)));
      }
    } while (bucket != first_bucket);
  } else {
    do {
      *p = TrNode_entry(node);
#ifdef TAG_LOW_BITS_32
      result = trie_to_list_floats_tag_low_32(result, TrNode_child(node), &p, &f);
#else
      PUSH_NEW_FLOAT_TERM(f);
#endif /* TAG_LOW_BITS_32 */
    } while((node = TrNode_next(node)));
  }

  return result;
}
#undef PUSH_NEW_FLOAT_TERM


#include "core_dbtries.c"