xref: /dports/math/gap/gap-4.11.0/pkg/kbmag-1.5.9/standalone/lib/fsa.c

/* file fsa.c - 16. 9. 94.
 *
 * 2/3/99 Bug fix in labeled_minimize();
 * Must have at least two iterations of main loop.
 *
 * 9/1/98 change generators from type char to type `gen'.
 * 2/10/97  - made minor changes necessary to handle compact table format.
 *            most functions will not handle this yet however.
 * 27.6.96. - added functions for computing growth function of an fsa
 *            written by Laurent Bartholdi
 * 1.5.96.  - adjusted srec_copy and srec_clear to deal with
 *            srec type "list of Integers".
 * 15.4.96. - added routing fsa_swap_coords().
 *
 * This file contains routines for manipulating finite state automata
 * The functions in this file currently only deal with deterministic fsa's
 *
 * 13.9.95. - wrote in code to handle srec type "list of words"
 * 17.11.94. - implemented labeled srec type and function fsa_labeled_minimize.
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "defs.h"
#include "fsa.h"
#include "hash.h"
#include "externals.h"

/* New functions written by Laurent Bartholdi for calculation of
 * growth rate of an fsa
 */
// unsigned *fsa_mod_count();	/* count # of accepted words mod. a prime */
// unsigned mod_inverse();
// int mod_solve();
// int fsa_mod_growth();		/* compute growth series mod. a prime */
// void mod_normal();
// boolean print_poly();
// int fsa_growth();
typedef struct {
  int nd, *num, dd, *den;
} fraction;

/* p1 points to the beginning of the row of targets from the required state
 * in a sparsely stored fsa, and p2 to the location beyond the end.
 * g is the generator number for which we seek the target.
 * If we don't find one, then there isn't one, and we return 0.
 * This only works for dfa's.
 */
int sparse_target(int g, int *p1, int *p2)
{
  while (p1 < p2) {
    if (*p1 == g)
      return *(p1 + 1);
    p1 += 2;
  }
  return 0;
}

/* Allocate space for the sub-structures of fsaptr, and zero all pointers. */
void fsa_init(fsa *fsaptr)
{
  int i;
  fsaptr->initial = 0;
  fsaptr->accepting = 0;
  fsaptr->is_accepting = 0;
  fsaptr->is_initial = 0;
  fsaptr->is_accessible = 0;

  tmalloc(fsaptr->alphabet, srec, 1);
  fsaptr->alphabet->names = 0;
  fsaptr->alphabet->words = 0;
  fsaptr->alphabet->wordslist = 0;
  fsaptr->alphabet->intlist = 0;
  fsaptr->alphabet->base = 0;
  fsaptr->alphabet->type = SIMPLE;
  fsaptr->alphabet->size = 0;
  fsaptr->alphabet->labels = 0;
  fsaptr->alphabet->setToLabels = 0;

  tmalloc(fsaptr->states, srec, 1);
  fsaptr->states->names = 0;
  fsaptr->states->words = 0;
  fsaptr->states->wordslist = 0;
  fsaptr->states->intlist = 0;
  fsaptr->states->base = 0;
  fsaptr->states->type = SIMPLE;
  fsaptr->states->size = 0;
  fsaptr->states->labels = 0;
  fsaptr->states->setToLabels = 0;

  for (i = 0; i < num_kbm_flag_strings; i++)
    fsaptr->flags[i] = FALSE;
  tmalloc(fsaptr->table, table_struc, 1);
  fsaptr->table->filename = 0;
  fsaptr->table->table_data_ptr = 0;
  fsaptr->table->ctable_data_ptr = 0;
  fsaptr->table->table_data_dptr = 0;
  fsaptr->table->comment_state_numbers = FALSE;
}

/* Intialize the table_data_ptr field of fsaptr->table,
 * for maxstates states, with table-type dense.
 * ne is the size of the alphabet.
 */
void fsa_table_init(table_struc *tableptr, int maxstates, int ne)
{
  int i;
  tableptr->maxstates = maxstates;
  tableptr->table_type = DENSE;
  tmalloc(tableptr->table_data_ptr, int *, ne + 1);
  tmalloc(tableptr->table_data_ptr[0], int, maxstates *ne);
  for (i = 1; i <= ne; i++)
    tableptr->table_data_ptr[i] =
        tableptr->table_data_ptr[0] + (i - 1) * maxstates - 1;
}

/* Set the is_initial field in fsa *fsaptr - should be freed after use  */
void fsa_set_is_initial(fsa *fsaptr)
{
  int ns, i;
  ns = fsaptr->states->size;
  tmalloc(fsaptr->is_initial, boolean, ns + 1);
  fsaptr->is_initial[0] = FALSE;
  if (fsaptr->num_initial == ns) {
    for (i = 1; i <= ns; i++)
      fsaptr->is_initial[i] = TRUE;
  }
  else {
    for (i = 1; i <= ns; i++)
      fsaptr->is_initial[i] = FALSE;
    for (i = 1; i <= fsaptr->num_initial; i++)
      fsaptr->is_initial[fsaptr->initial[i]] = TRUE;
  }
}

/* Set the is_accepting field in fsa *fsaptr - should be freed after use */
void fsa_set_is_accepting(fsa *fsaptr)
{
  int ns, i;
  ns = fsaptr->states->size;
  tmalloc(fsaptr->is_accepting, boolean, ns + 1);
  fsaptr->is_accepting[0] = FALSE;
  if (fsaptr->num_accepting == ns) {
    for (i = 1; i <= ns; i++)
      fsaptr->is_accepting[i] = TRUE;
  }
  else {
    for (i = 1; i <= ns; i++)
      fsaptr->is_accepting[i] = FALSE;
    for (i = 1; i <= fsaptr->num_accepting; i++)
      fsaptr->is_accepting[fsaptr->accepting[i]] = TRUE;
  }
}

/* Set the is_accessible field in fsa *fsaptr - should be freed after use */
void fsa_set_is_accessible(fsa *fsaptr)
{
  int ns, ne, ct, i, *gotlist, **table, j, k, l, *ptr, *ptre;
  ;

  ns = fsaptr->states->size;
  ne = fsaptr->alphabet->size;

  tmalloc(gotlist, int, ns + 1);
  tmalloc(fsaptr->is_accessible, boolean, ns + 1);
  table = fsaptr->table->table_data_ptr;
  ct = 0;
  if (fsaptr->num_initial == ns) {
    for (i = 1; i <= ns; i++)
      fsaptr->is_accessible[i] = TRUE;
    return;
  }
  for (i = 1; i <= ns; i++)
    fsaptr->is_accessible[i] = FALSE;
  for (i = 1; i <= fsaptr->num_initial; i++) {
    fsaptr->is_accessible[fsaptr->initial[i]] = TRUE;
    gotlist[++ct] = fsaptr->initial[i];
  }
  for (i = 1; i <= ct; i++) {
    k = gotlist[i];
    if (fsaptr->table->table_type == DENSE)
      for (j = 1; j <= ne; j++) {
        l = table[j][k];
        if (l > 0 && !fsaptr->is_accessible[l]) {
          fsaptr->is_accessible[l] = TRUE;
          gotlist[++ct] = l;
        }
      }
    else {
      ptr = table[k];
      ptre = table[k + 1];
      while (ptr < ptre) {
        l = *(++ptr);
        if (l > 0 && !fsaptr->is_accessible[l]) {
          fsaptr->is_accessible[l] = TRUE;
          gotlist[++ct] = l;
        }
        ptr++;
      }
    }
  }
  tfree(gotlist);
}

/* Set the field fsaptr->table->table_data_dptr.
 * This is used for fast access to table entries in 2-variable machines.
 */
int fsa_table_dptr_init(fsa *fsaptr)
{
  int i, ngens;
  if (fsaptr->alphabet->type != PRODUCT || fsaptr->alphabet->arity != 2) {
    fprintf(stderr, "Error in fsa_table_dptr_init: fsa must be 2-variable.\n");
    return -1;
  }
  if (fsaptr->table->table_type != DENSE) {
    fprintf(stderr,
            "Error in fsa_table_dptr_init: storage-type must be dense.\n");
    return -1;
  }
  ngens = fsaptr->alphabet->base->size;
  if (fsaptr->table->table_data_dptr == 0) {
    tmalloc(fsaptr->table->table_data_dptr, int **, ngens + 2);
    for (i = 1; i <= ngens + 1; i++)
      fsaptr->table->table_data_dptr[i] =
          fsaptr->table->table_data_ptr + (i - 1) * (ngens + 1);
  }
  return 0;
}

/* Deallocate all space used by the set-record fsaptr */
void srec_clear(srec *srptr)
{
  int i, j;
  if (srptr == 0)
    return;
  if ((srptr->type == IDENTIFIERS || srptr->type == STRINGS) && srptr->names) {
    for (i = 1; i <= srptr->size; i++)
      tfree(srptr->names[i]);
    tfree(srptr->names);
  }
  if (srptr->type == WORDS && srptr->words) {
    for (i = 1; i <= srptr->size; i++)
      tfree(srptr->words[i]);
    tfree(srptr->words);
  }
  if (srptr->type == LISTOFWORDS && srptr->wordslist) {
    for (i = 1; i <= srptr->size; i++) {
      j = 0;
      while (srptr->wordslist[i][j]) {
        tfree(srptr->wordslist[i][j]);
        j++;
      }
      tfree(srptr->wordslist[i]);
    }
    tfree(srptr->wordslist);
  }
  if (srptr->type == LISTOFINTS && srptr->intlist) {
    for (i = 1; i <= srptr->size; i++)
      tfree(srptr->intlist[i]) tfree(srptr->intlist);
  }
  if (srptr->type == PRODUCT && srptr->base) {
    srec_clear(srptr->base);
    tfree(srptr->base);
  }
  if (srptr->type == WORDS || srptr->type == LISTOFWORDS)
    for (i = 1; i <= srptr->alphabet_size; i++)
      tfree(srptr->alphabet[i]);
  if (srptr->type == LABELED) {
    srec_clear(srptr->labels);
    tfree(srptr->labels);
    tfree(srptr->setToLabels);
  }
}

/* Copy the information in *srptr2 to *srptr1 (same way round as strcpy!)
 * It is assumed that srptr1 points to a zeroed set-record.
 */
void srec_copy(srec *srptr1, srec *srptr2)
{
  int i, j, l;
  srptr1->type = srptr2->type;
  srptr1->size = srptr2->size;
  if (srptr1->type == IDENTIFIERS || srptr1->type == STRINGS) {
    tmalloc(srptr1->names, char *, srptr1->size + 1);
    for (i = 1; i <= srptr1->size; i++) {
      tmalloc(srptr1->names[i], char, stringlen(srptr2->names[i]) + 1);
      strcpy(srptr1->names[i], srptr2->names[i]);
    }
  }
  if (srptr1->type == WORDS) {
    tmalloc(srptr1->words, gen *, srptr1->size + 1);
    for (i = 1; i <= srptr1->size; i++) {
      tmalloc(srptr1->words[i], gen, genstrlen(srptr2->words[i]) + 1);
      genstrcpy(srptr1->words[i], srptr2->words[i]);
    }
  }
  if (srptr1->type == LISTOFWORDS) {
    tmalloc(srptr1->wordslist, gen **, srptr1->size + 1);
    for (i = 1; i <= srptr1->size; i++) {
      /* First find length of srptr2->wordslist[i] */
      l = 0;
      while (srptr2->wordslist[i][l])
        l++;
      tmalloc(srptr1->wordslist[i], gen *, l + 1);
      for (j = 0; j < l; j++) {
        tmalloc(srptr1->wordslist[i][j], gen,
                genstrlen(srptr2->wordslist[i][j]) + 1);
        genstrcpy(srptr1->wordslist[i][j], srptr2->wordslist[i][j]);
      }
      srptr1->wordslist[i][l] = 0;
    }
  }
  if (srptr1->type == LISTOFINTS) {
    tmalloc(srptr1->intlist, int *, srptr1->size + 1);
    for (i = 1; i <= srptr1->size; i++) {
      l = srptr2->intlist[i][0];
      tmalloc(srptr1->intlist[i], int, l + 1);
      for (j = 0; j <= l; j++) {
        srptr1->intlist[i][j] = srptr2->intlist[i][j];
      }
    }
  }
  if (srptr1->type == WORDS || srptr1->type == LISTOFWORDS) {
    srptr1->alphabet_size = srptr2->alphabet_size;
    for (i = 1; i <= srptr1->alphabet_size; i++) {
      tmalloc(srptr1->alphabet[i], char, stringlen(srptr2->alphabet[i]) + 1);
      strcpy(srptr1->alphabet[i], srptr2->alphabet[i]);
    }
  }
  if (srptr1->type == PRODUCT) {
    tmalloc(srptr1->base, srec, 1);
    srec_copy(srptr1->base, srptr2->base);
    srptr1->arity = srptr2->arity;
    srptr1->padding = srptr2->padding;
  }
  if (srptr1->type == LABELED) {
    tmalloc(srptr1->labels, srec, 1);
    srec_copy(srptr1->labels, srptr2->labels);
    tmalloc(srptr1->setToLabels, setToLabelsType, srptr1->size + 1);
    for (i = 1; i <= srptr1->size; i++)
      srptr1->setToLabels[i] = srptr2->setToLabels[i];
  }
}


/* Copy the information in *tableptr2 to *tableptr1 (same way round as strcpy!)
 * It is assumed that tableptr1 points to a zeroed table_struc.
 * ne and ns are the sizes of the alphabet and state-set.
 */
void table_copy(table_struc *tableptr1, table_struc *tableptr2, int ne, int ns)
{
  int i, j, maxstates, dr, space, *row1, *row2, *ptr1, *ptr2, *ptr2e;
  if (tableptr2->filename) {
    tmalloc(tableptr1->filename, char, stringlen(tableptr2->filename) + 1);
    strcpy(tableptr1->filename, tableptr2->filename);
  }
  tableptr1->table_type = tableptr2->table_type;
  tableptr1->printing_format = tableptr2->printing_format;
  tableptr1->comment_state_numbers = tableptr2->comment_state_numbers;
  tableptr1->numTransitions = tableptr2->numTransitions;
  dr = tableptr1->denserows = tableptr2->denserows;
  maxstates = tableptr1->maxstates = tableptr2->maxstates;

  if (tableptr1->table_type == DENSE) {
    tmalloc(tableptr1->table_data_ptr, int *, ne + 1);
    tmalloc(tableptr1->table_data_ptr[0], int, ne *maxstates);
    for (i = 1; i <= ne; i++) {
      row2 = tableptr2->table_data_ptr[i];
      row1 = tableptr1->table_data_ptr[i] =
          tableptr1->table_data_ptr[0] + (i - 1) * maxstates - 1;
      for (j = 1; j <= ns; j++)
        row1[j] = row2[j];
    }
  }
  else {
    tmalloc(tableptr1->table_data_ptr, int *, ns + 2);
    if (dr > 0) {
      tmalloc(tableptr1->table_data_ptr[0], int, ne *dr);
      for (i = 1; i <= dr; i++) {
        row2 = tableptr2->table_data_ptr[i];
        row1 = tableptr1->table_data_ptr[i] =
            tableptr1->table_data_ptr[0] + (i - 1) * ne - 1;
        for (j = 1; j <= ne; j++)
          row1[j] = row2[j];
      }
      if (ns > dr) {
        space = tableptr2->table_data_ptr[ns + 1] -
                tableptr2->table_data_ptr[dr + 1];
        tmalloc(tableptr1->table_data_ptr[dr + 1], int, space + 1);
        ptr1 = tableptr1->table_data_ptr[dr + 1];
      }
    }
    else {
      space = tableptr2->table_data_ptr[ns + 1] - tableptr2->table_data_ptr[0];
      tmalloc(tableptr1->table_data_ptr[0], int, space + 1);
      ptr1 = tableptr1->table_data_ptr[0];
    }
    if (ns > dr) {
      ptr2 = tableptr2->table_data_ptr[dr + 1];
      for (i = dr + 1; i <= ns; i++) {
        tableptr1->table_data_ptr[i] = ptr1;
        ptr2e = tableptr2->table_data_ptr[i + 1];
        while (ptr2 < ptr2e)
          *(ptr1++) = *(ptr2++);
      }
      tableptr1->table_data_ptr[ns + 1] = ptr1;
    }
  }
}


/* Copy the information in *fsaptr2 to *fsaptr1 (same way round as strcpy!)
 * It is assumed that fsaptr1 points to a zeroed fsa.
 */
void fsa_copy(fsa *fsaptr1, fsa *fsaptr2)
{
  int i, ne, ns;
  fsa_init(fsaptr1);
  srec_copy(fsaptr1->alphabet, fsaptr2->alphabet);
  srec_copy(fsaptr1->states, fsaptr2->states);
  ne = fsaptr1->alphabet->size;
  ns = fsaptr1->states->size;

  fsaptr1->num_initial = fsaptr2->num_initial;
  tmalloc(fsaptr1->initial, int, fsaptr1->num_initial + 1);
  for (i = 1; i <= fsaptr1->num_initial; i++)
    fsaptr1->initial[i] = fsaptr2->initial[i];

  fsaptr1->num_accepting = fsaptr2->num_accepting;
  if (ns == 1 || fsaptr1->num_accepting != ns) {
    tmalloc(fsaptr1->accepting, int, fsaptr1->num_accepting + 1);
    for (i = 1; i <= fsaptr1->num_accepting; i++)
      fsaptr1->accepting[i] = fsaptr2->accepting[i];
  }

  for (i = 0; i < num_kbm_flag_strings; i++)
    fsaptr1->flags[i] = fsaptr2->flags[i];

  table_copy(fsaptr1->table, fsaptr2->table, ne, ns);
}

/* Deallocate all space used by the table-struc fsaptr */
void table_clear(table_struc *tableptr, int ns)
{
  if (tableptr == 0)
    return;
  tfree(tableptr->filename);
  if (tableptr->table_data_ptr) {
    tfree(tableptr->table_data_ptr[0]);
    if (tableptr->table_type == SPARSE && tableptr->denserows > 0 &&
        tableptr->denserows < ns)
      tfree(tableptr->table_data_ptr[tableptr->denserows + 1]);
    tfree(tableptr->table_data_ptr);
    tfree(tableptr->ctable_data_ptr);
    tfree(tableptr->table_data_dptr);
  }
}

/* Deallocate all space used by the fsa *fsaptr */
void fsa_clear(fsa *fsaptr)
{
  int ns;
  if (fsaptr == 0)
    return;
  srec_clear(fsaptr->states);
  tfree(fsaptr->states);
  srec_clear(fsaptr->alphabet);
  tfree(fsaptr->alphabet);
  tfree(fsaptr->initial);
  tfree(fsaptr->accepting);
  tfree(fsaptr->is_accepting);
  tfree(fsaptr->is_initial);
  tfree(fsaptr->is_accessible);
  ns = fsaptr->states ? fsaptr->states->size : 0;
  table_clear(fsaptr->table, ns);
  tfree(fsaptr->table);
}

/* Delete state number stateno from the fsa *fsaptr - works for all fsa's.
 * Warning - the arrays fsaptr->is_initial, is_accepting and is_accessible
 * are not updated!
 */
int fsa_delete_state(fsa *fsaptr, int stateno)
{
  int ns, ne, **table, *ptr, *ptr2, *ptr2e, i, j, k, l;
  srec *srptr;

  if (fsaptr->table->table_type == SPARSE && fsaptr->table->denserows > 0) {
    fprintf(stderr, "Sorry: fsa_delete_state not available for sparse storage "
                    "with dense rows.\n");
    return -1;
    ;
  }

  if (kbm_print_level >= 3)
    printf("    #Calling fsa_delete_state on state number %d.\n", stateno);
  ne = fsaptr->alphabet->size;
  srptr = fsaptr->states;
  ns = srptr->size;
  if (stateno <= 0 || stateno > ns) {
    fprintf(stderr, "Error in fsa_delete_stateno - invalid state number.\n");
    return -1;
    ;
  }
  if (srptr->type == IDENTIFIERS || srptr->type == STRINGS) {
    tfree(srptr->names[stateno]);
    for (i = stateno; i < ns; i++)
      srptr->names[i] = srptr->names[i + 1];
    srptr->names[ns] = 0;
  }
  if (srptr->type == WORDS) {
    tfree(srptr->words[stateno]);
    for (i = stateno; i < ns; i++)
      srptr->words[i] = srptr->words[i + 1];
    srptr->words[ns] = 0;
  }
  if (srptr->type == LISTOFWORDS) {
    j = 0;
    while (srptr->wordslist[stateno][j]) {
      tfree(srptr->wordslist[stateno][j]);
      j++;
    }
    tfree(srptr->wordslist[stateno]);
    for (i = stateno; i < ns; i++)
      srptr->wordslist[i] = srptr->wordslist[i + 1];
    srptr->wordslist[ns] = 0;
  }
  if (srptr->type == LISTOFINTS) {
    tfree(srptr->intlist[stateno]);
    for (i = stateno; i < ns; i++)
      srptr->intlist[i] = srptr->intlist[i + 1];
    srptr->intlist[ns] = 0;
  }
  if (srptr->type == LABELED)
    for (i = stateno; i < ns; i++)
      srptr->setToLabels[i] = srptr->setToLabels[i + 1];

  for (i = 1; i <= fsaptr->num_initial; i++) {
    k = fsaptr->initial[i];
    if (k == stateno) {
      for (j = i; j < fsaptr->num_initial; j++) {
        l = fsaptr->initial[j + 1];
        fsaptr->initial[j] = l > stateno ? l - 1 : l;
      }
      fsaptr->num_initial--;
      break;
    }
    else if (k > stateno)
      fsaptr->initial[i] = k - 1;
  }

  if (fsaptr->num_accepting == ns) {
    fsaptr->num_accepting--;
    if (ns == 2) {
      tmalloc(fsaptr->accepting, int, 2);
      fsaptr->accepting[1] = 1;
    }
  }
  else
    for (i = 1; i <= fsaptr->num_accepting; i++) {
      k = fsaptr->accepting[i];
      if (k == stateno) {
        for (j = i; j < fsaptr->num_accepting; j++) {
          l = fsaptr->accepting[j + 1];
          fsaptr->accepting[j] = l > stateno ? l - 1 : l;
        }
        fsaptr->num_accepting--;
        break;
      }
      else if (k > stateno)
        fsaptr->accepting[i] = k - 1;
    }

  fsaptr->flags[NFA] = FALSE;
  fsaptr->flags[ACCESSIBLE] = FALSE;
  fsaptr->flags[TRIM] = FALSE;
  fsaptr->flags[BFS] = FALSE;
  fsaptr->flags[MINIMIZED] = FALSE;

  table = fsaptr->table->table_data_ptr;
  if (fsaptr->table->table_type == DENSE) {
    for (j = 1; j <= ne; j++) {
      for (i = 1; i < stateno; i++)
        if (table[j][i] > stateno)
          table[j][i]--;
        else if (table[j][i] == stateno)
          table[j][i] = 0;
      for (i = stateno; i < ns; i++) {
        k = table[j][i + 1];
        table[j][i] = k < stateno ? k : k == stateno ? 0 : k - 1;
      }
    }
  }
  else {
    ptr = fsaptr->table->table_data_ptr[0];
    ptr2 = ptr;
    for (i = 1; i < stateno; i++) {
      table[i] = ptr;
      ptr2e = table[i + 1];
      while (ptr2 < ptr2e) {
        if (*(ptr2 + 1) != stateno) {
          *(ptr++) = *(ptr2++);
          *(ptr++) = *ptr2 > stateno ? *ptr2 - 1 : *ptr2;
          ptr2++;
        }
        else
          ptr2 += 2;
      }
    }
    ptr2 = table[stateno + 1];
    for (i = stateno; i < ns; i++) {
      table[i] = ptr;
      ptr2e = table[i + 2];
      while (ptr2 < ptr2e) {
        if (*(ptr2 + 1) != stateno) {
          *(ptr++) = *(ptr2++);
          *(ptr++) = *ptr2 > stateno ? *ptr2 - 1 : *ptr2;
          ptr2++;
        }
        else
          ptr2 += 2;
      }
    }
    table[ns] = ptr;
  }
  fsaptr->states->size--;
  return 0;
}

/* permute the states of fsa *fsaptr, using perm - works for all fsa's
 * perm should be a permutation of the integers 1 to ns - this is not
 * checked Warning - the arrays fsaptr->is_initial, is_accepting and
 * is_accessible are not updated. ALSO - perm[0] should be 0 !!
 */
int fsa_permute_states(fsa *fsaptr, int *perm)
{
  int ns, ne, *newtable, **newtableptr, **table, *perminv, *ptr, *ptr2, *ptr2e,
      i, j;
  srec *srptr;
  char **newnames;
  gen **newwords;
  gen ***newwordslist;
  int **newintlist;
  setToLabelsType *newsetToLabels;

  if (fsaptr->table->table_type == SPARSE && fsaptr->table->denserows > 0) {
    fprintf(stderr, "Sorry: fsa_permute_state not available for sparse storage "
                    "with dense rows.\n");
    return -1;
  }
  if (kbm_print_level >= 3)
    printf("    #Calling fsa_permute_states.\n");
  perm[0] = 0; /* let's make sure! */
  ne = fsaptr->alphabet->size;
  srptr = fsaptr->states;
  ns = srptr->size;
  if (srptr->type == IDENTIFIERS || srptr->type == STRINGS) {
    tmalloc(newnames, char *, ns + 1);
    for (i = 1; i <= ns; i++)
      newnames[perm[i]] = srptr->names[i];
    tfree(srptr->names);
    srptr->names = newnames;
  }
  if (srptr->type == WORDS) {
    tmalloc(newwords, gen *, ns + 1);
    for (i = 1; i <= ns; i++)
      newwords[perm[i]] = srptr->words[i];
    tfree(srptr->words);
    srptr->words = newwords;
  }
  if (srptr->type == LISTOFWORDS) {
    tmalloc(newwordslist, gen **, ns + 1);
    for (i = 1; i <= ns; i++)
      newwordslist[perm[i]] = srptr->wordslist[i];
    tfree(srptr->wordslist);
    srptr->wordslist = newwordslist;
  }
  if (srptr->type == LISTOFINTS) {
    tmalloc(newintlist, int *, ns + 1);
    for (i = 1; i <= ns; i++)
      newintlist[perm[i]] = srptr->intlist[i];
    tfree(srptr->intlist);
    srptr->intlist = newintlist;
  }
  if (srptr->type == LABELED) {
    tmalloc(newsetToLabels, setToLabelsType, ns + 1);
    for (i = 1; i <= ns; i++)
      newsetToLabels[perm[i]] = srptr->setToLabels[i];
    tfree(srptr->setToLabels);
    srptr->setToLabels = newsetToLabels;
  }

  if (fsaptr->num_initial != ns) {
    tmalloc(fsaptr->is_initial, boolean, ns + 1);
    for (i = 1; i <= ns; i++)
      fsaptr->is_initial[i] = FALSE;
    for (i = 1; i <= fsaptr->num_initial; i++)
      fsaptr->is_initial[perm[fsaptr->initial[i]]] = TRUE;
    j = 0;
    for (i = 1; i <= ns; i++)
      if (fsaptr->is_initial[i])
        fsaptr->initial[++j] = i;
    tfree(fsaptr->is_initial);
  }

  if (fsaptr->num_accepting != ns) {
    tmalloc(fsaptr->is_accepting, boolean, ns + 1);
    for (i = 1; i <= ns; i++)
      fsaptr->is_accepting[i] = FALSE;
    for (i = 1; i <= fsaptr->num_accepting; i++)
      fsaptr->is_accepting[perm[fsaptr->accepting[i]]] = TRUE;
    j = 0;
    for (i = 1; i <= ns; i++)
      if (fsaptr->is_accepting[i])
        fsaptr->accepting[++j] = i;
    tfree(fsaptr->is_accepting);
  }

  fsaptr->flags[BFS] = FALSE;

  table = fsaptr->table->table_data_ptr;
  if (fsaptr->table->table_type == DENSE) {
    perm[0] = 0; /* just to make sure! */
    tmalloc(newtable, int, ns *ne);
    for (j = 1; j <= ne; j++) {
      ptr = newtable + (j - 1) * ns - 1;
      for (i = 1; i <= ns; i++)
        ptr[perm[i]] = perm[table[j][i]];
      table[j] = ptr;
    }
    tfree(fsaptr->table->table_data_ptr[0]);
    fsaptr->table->table_data_ptr[0] = newtable;
  }
  else {
    /* We need the inverse of perm in this case */
    tmalloc(perminv, int, ns + 1);
    for (i = 1; i <= ns; i++)
      perminv[perm[i]] = i;
    tmalloc(newtable, int, table[ns + 1] - table[1]);
    tmalloc(newtableptr, int *, ns + 2);
    ptr = newtable;
    for (i = 1; i <= ns; i++) {
      newtableptr[i] = ptr;
      ptr2 = table[perminv[i]];
      ptr2e = table[perminv[i] + 1];
      while (ptr2 < ptr2e) {
        *(ptr++) = *(ptr2++);
        *(ptr++) = perm[*(ptr2++)];
      }
    }
    newtableptr[ns + 1] = ptr;
    tfree(perminv);
    tfree(fsaptr->table->table_data_ptr[0]);
    tfree(fsaptr->table->table_data_ptr);
    fsaptr->table->table_data_ptr = newtableptr;
    fsaptr->table->table_data_ptr[0] = newtable;
  }
  return 0;
}

/* If *fsaptr is an rws (rewriting-system) automaton, then it may have
 * negative targets, which point to reduction equations.
 * This function simply replaces all of these targets by 0, to make it
 * into a conventional fsa.
 */
int fsa_clear_rws(fsa *fsaptr)
{
  int ns, ne, **table, *ptr, *ptr2, *ptr2e, i, j;

  if (fsaptr->table->table_type == SPARSE && fsaptr->table->denserows > 0) {
    fprintf(stderr, "Sorry: fsa_clear_rws not available for sparse storage "
                    "with dense rows.\n");
    return -1;
  }
  if (fsaptr->flags[RWS] == FALSE)
    return 0;

  ne = fsaptr->alphabet->size;
  ns = fsaptr->states->size;

  table = fsaptr->table->table_data_ptr;
  if (fsaptr->table->table_type == DENSE) {
    for (j = 1; j <= ne; j++)
      for (i = 1; i <= ns; i++)
        if (table[j][i] < 0)
          table[j][i] = 0;
  }
  else {
    ptr = table[1];
    for (i = 1; i <= ns; i++) {
      ptr2 = table[i];
      ptr2e = table[i + 1];
      table[i] = ptr;
      while (ptr2 < ptr2e) {
        if (*(ptr2 + 1) > 0) {
          *(ptr++) = *(ptr2++);
          *(ptr++) = *(ptr2++);
        }
        else
          ptr2 += 2;
      }
    }
    table[ns + 1] = ptr;
  }

  fsaptr->flags[RWS] = FALSE;
  return 0;
}

/* Make the fsa *fsaptr accessible - i.e. all states reachable from
 * start-state
 */
int fsa_make_accessible(fsa *fsaptr)
{
  int ns, i;
  storage_type st = fsaptr->table->table_type;
  fsa *temp;

  if (st == SPARSE && fsaptr->table->denserows > 0) {
    fprintf(stderr, "Sorry: fsa_make_accessible unavailable for sparse storage "
                    "with dense rows.\n");
    return -1;
  }
  if (kbm_print_level >= 3)
    printf("    #Calling fsa_make_accessible.\n");
  if (fsaptr->flags[MINIMIZED] || fsaptr->flags[ACCESSIBLE] ||
      fsaptr->flags[TRIM])
    return 0;

  if (fsaptr->flags[RWS])
    fsa_clear_rws(fsaptr);

  ns = fsaptr->states->size;

  if (fsaptr->num_initial == ns) {
    fsaptr->flags[ACCESSIBLE] = TRUE;
    return 0;
  }

  /* In the deterministic case, we do it by and-ing it with itself - should
   * write separate code for this really, but it hardly seems worth it. This
   * works faster than deleting redundant states.
   */
  if (fsaptr->flags[DFA] && fsaptr->states->type != LABELED) {
    temp = fsa_and(fsaptr, fsaptr, st, TRUE, "/tmp/fsa_and_xxx");
    fsa_copy(fsaptr, temp);
    fsa_clear(temp);
    tfree(temp);
    return 0;
  }

  /* Now find the list of states accessible from the start-state. */
  fsa_set_is_accessible(fsaptr);

  /* Now delete inaccessible states */
  for (i = ns; i >= 1; i--)
    if (!fsaptr->is_accessible[i])
      fsa_delete_state(fsaptr, i);

  tfree(fsaptr->is_accessible);
  return 0;
}

/* Minimize the fsa *fsaptr. */
int fsa_minimize(fsa *fsaptr)
{
  int *block_numa, *block_numb, *block_swap, i, j, k, l, len, *ptr, *ptr2,
      *ptr2e, *ht_ptr, ne, ns_orig, **table, ns_final, ns_new, num_iterations;
  hash_table ht;
  boolean fixed, acc;

  if (fsaptr->table->table_type == SPARSE && fsaptr->table->denserows > 0) {
    fprintf(stderr, "Sorry: fsa_minimize unavailable for sparse storage with "
                    "dense rows.\n");
    return -1;
  }

  if (kbm_print_level >= 3)
    printf("    #Calling fsa_minimize.\n");
  if (!fsaptr->flags[DFA]) {
    fprintf(stderr, "Error: fsa_minimize only applies to DFA's.\n");
    return -1;
  }
  if (fsaptr->flags[MINIMIZED])
    return 0;

  if (fsaptr->flags[RWS])
    fsa_clear_rws(fsaptr);

  acc = fsaptr->flags[ACCESSIBLE] || fsaptr->flags[TRIM];
  if (!acc)
    fsa_set_is_accessible(fsaptr);

  ns_orig = fsaptr->states->size;
  if (ns_orig == 0) {
    fsaptr->flags[TRIM] = TRUE;
    fsaptr->flags[MINIMIZED] = TRUE;
    tfree(fsaptr->is_accessible);
    return 0;
  }

  /* First throw away any existing structure on the state-set. */
  srec_clear(fsaptr->states);
  fsaptr->states->type = SIMPLE;
  ne = fsaptr->alphabet->size;
  table = fsaptr->table->table_data_ptr;

  tmalloc(block_numa, int, ns_orig + 1);
  tmalloc(block_numb, int, ns_orig + 1);
  for (i = 0; i <= ns_orig; i++)
    block_numb[i] = 0;
  /* Start with block_numa equal to the accept/reject division
   * Remember that state/block number 0 is always failure with no hope.
   */
  if (fsaptr->num_accepting == ns_orig) {
    block_numa[0] = 0;
    for (i = 1; i <= ns_orig; i++)
      if (acc || fsaptr->is_accessible[i])
        block_numa[i] = 1;
      else
        block_numa[i] = 0;
  }
  else {
    for (i = 0; i <= ns_orig; i++)
      block_numa[i] = 0;
    for (i = 1; i <= fsaptr->num_accepting; i++)
      if (acc || fsaptr->is_accessible[fsaptr->accepting[i]])
        block_numa[fsaptr->accepting[i]] = 1;
  }

  fixed = fsaptr->table->table_type == DENSE;

  ns_new = 1;
  num_iterations = 0;
  /* The main refinement loop follows. */
  do {
    num_iterations++;
    ns_final = ns_new;
    /* Turn off excessive printing at this point */
    j = kbm_print_level;
    kbm_print_level = 1;
    hash_init(&ht, fixed, ne + 1, 0, 0);
    kbm_print_level = j;
    if (kbm_print_level >= 3)
      printf("    #Iterating - number of state categories = %d.\n", ns_new);
    block_numb[0] = 0;
    for (i = 1; i <= ns_orig; i++)
      if (acc || fsaptr->is_accessible[i]) {
        /* Insert the encoded form of the transitions from state i into the
         * hashtable preceded by the current block number of i.
         */
        len = fixed ? ne + 1 : table[i + 1] - table[i] + 1;
        ptr = ht.current_ptr;
        *ptr = block_numa[i];
        if (fixed) {
          for (j = 1; j < len; j++)
            ptr[j] = block_numa[table[j][i]];
          l = len;
        }
        else {
          l = 0;
          for (j = 1; j < len; j += 2) {
            k = block_numa[table[i][j]];
            if (k > 0) {
              ptr[++l] = table[i][j - 1];
              ptr[++l] = k;
            }
          }
          if (l > 0 || *ptr > 0)
            l++;
          /* For technical reasons, we want the zero record to be empty */
        }
        block_numb[i] = hash_locate(&ht, l);
        if (block_numb[i] == -1)
          return -1;
      }
      else
        block_numb[i] = 0;
    ns_new = ht.num_recs;
    block_swap = block_numa;
    block_numa = block_numb;
    block_numb = block_swap;
    if (ns_new > ns_final)
      hash_clear(&ht);
  } while (ns_new > ns_final);

  if (kbm_print_level >= 4) { /* print out old-new state correspondence */
    printf("Old State   NewState\n");
    for (i = 1; i <= ns_orig; i++)
      printf("   %6d     %6d\n", i, block_numa[i]);
  }

  /* At this stage, either ns_final = ns_new, or the fsa has empty accepted
   * language, ns_new=0 and ns_final=1.
   */

  fsaptr->flags[TRIM] = TRUE;
  fsaptr->flags[MINIMIZED] = TRUE;

  if (ns_new == 0) {
    /* This is the awkward case of no states - always causes problems! */
    fsaptr->states->size = 0;
    fsaptr->num_initial = 0;
    tfree(fsaptr->initial);
    fsaptr->num_accepting = 0;
    tfree(fsaptr->accepting);
    tfree(fsaptr->table->table_data_ptr[0]);
    tfree(fsaptr->table->table_data_ptr);
  }
  else if (ns_final < ns_orig) {
    /* Re-define the fsa fields  */
    fsaptr->states->size = ns_final;

    fsaptr->initial[1] = block_numa[fsaptr->initial[1]];

    if (fsaptr->num_accepting == ns_orig) {
      fsaptr->num_accepting = ns_final;
      if (ns_final == 1) {
        tmalloc(fsaptr->accepting, int, 2);
        fsaptr->accepting[1] = 1;
      }
    }
    else {
      tmalloc(fsaptr->is_accepting, boolean, ns_final + 1);
      for (i = 1; i <= ns_final; i++)
        fsaptr->is_accepting[i] = FALSE;
      for (i = 1; i <= fsaptr->num_accepting; i++)
        fsaptr->is_accepting[block_numa[fsaptr->accepting[i]]] = TRUE;
      fsaptr->num_accepting = 0;
      for (i = 1; i <= ns_final; i++)
        if (fsaptr->is_accepting[i])
          fsaptr->num_accepting++;
      tfree(fsaptr->accepting);
      tmalloc(fsaptr->accepting, int, fsaptr->num_accepting + 1);
      j = 0;
      for (i = 1; i <= ns_final; i++)
        if (fsaptr->is_accepting[i])
          fsaptr->accepting[++j] = i;
      tfree(fsaptr->is_accepting);
    }

    /* Finally copy the transition table data from the hash-table back to the
     * fsa */
    tfree(fsaptr->table->table_data_ptr[0]);
    tfree(fsaptr->table->table_data_ptr);
    if (fixed) {
      fsa_table_init(fsaptr->table, ns_final, ne);
      table = fsaptr->table->table_data_ptr;
      for (i = 1; i <= ns_final; i++) {
        ht_ptr = hash_rec(&ht, i);
        for (j = 1; j <= ne; j++)
          table[j][i] = ht_ptr[j];
      }
    }
    else {
      tmalloc(fsaptr->table->table_data_ptr, int *, ns_final + 2);
      tmalloc(fsaptr->table->table_data_ptr[0], int, ht.tot_space - ns_final);
      table = fsaptr->table->table_data_ptr;
      table[1] = ptr = table[0];
      for (i = 1; i <= ns_final; i++) {
        ht_ptr = hash_rec(&ht, i);
        ptr2 = ht_ptr + 1;
        ptr2e = ht_ptr + hash_rec_len(&ht, i) - 1;
        while (ptr2 <= ptr2e)
          *(ptr++) = *(ptr2++);
        table[i + 1] = ptr;
      }
    }
  }
  hash_clear(&ht);
  tfree(block_numa);
  tfree(block_numb);
  tfree(fsaptr->is_accessible);
  if (kbm_print_level >= 3)
    printf("    #Number of iterations = %d.\n", num_iterations);
  return 0;
}

/* This is the minimization function for fsa's which might have more than
 * two categories of states.
 * We use the labeled set-record type to identify the categories, so *fsaptr
 * must have state-set of labeled type.
 * The accepting states should be a union of some of the state
 * categories, or else the accepting states of the result will be
 * meaningless!
 */
int fsa_labeled_minimize(fsa *fsaptr)
{
  int *block_numa, *block_numb, *block_swap, i, j, k, l, len, *ptr, *ptr2,
      *ptr2e, *ht_ptr, ne, ns_orig, **table, ns_final, ns_new, num_iterations;
  hash_table ht;
  boolean fixed, *occurs, acc;

  if (fsaptr->table->table_type == SPARSE && fsaptr->table->denserows > 0) {
    fprintf(stderr, "Sorry: fsa_labeled_minimize unavailable for sparse "
                    "storage with dense rows.\n");
    return -1;
  }
  if (kbm_print_level >= 3)
    printf("    #Calling fsa_labeled_minimize.\n");
  if (!fsaptr->flags[DFA]) {
    fprintf(stderr, "Error: fsa_labeled_minimize only applies to DFA's.\n");
    return -1;
  }

  if (fsaptr->states->type != LABELED) {
    fprintf(
        stderr,
        "Error: in fsa_labeled_minimize state-set must have type labeled.\n");
    return -1;
  }

  if (fsaptr->flags[RWS])
    fsa_clear_rws(fsaptr);

  acc = fsaptr->flags[ACCESSIBLE] || fsaptr->flags[TRIM];
  if (!acc)
    fsa_set_is_accessible(fsaptr);

  ne = fsaptr->alphabet->size;
  table = fsaptr->table->table_data_ptr;
  ns_orig = fsaptr->states->size;
  if (ns_orig == 0) {
    tfree(fsaptr->is_accessible);
    return 0;
  }

  /* Start with block_numa equal to the subdivision defined by the labeling.  */
  tmalloc(occurs, boolean, fsaptr->states->labels->size + 1);
  for (i = 1; i <= fsaptr->states->labels->size; i++)
    occurs[i] = FALSE;
  tmalloc(block_numa, int, ns_orig + 1);
  tmalloc(block_numb, int, ns_orig + 1);
  for (i = 0; i <= ns_orig; i++)
    block_numb[i] = 0;
  ns_new = 0;
  block_numa[0] = 0; /* The zero state is always regarded as having label 0 */
  for (i = 1; i <= ns_orig; i++)
    if (acc || fsaptr->is_accessible[i]) {
      j = fsaptr->states->setToLabels[i];
      if (j > 0 && !occurs[j]) {
        occurs[j] = TRUE;
        ns_new++;
      }
      block_numa[i] = j;
    }
    else
      block_numa[i] = 0;
  tfree(occurs);
  if (ns_new == 0)
    ns_new = 1; /* a patch for the case when there are no labels */

  fixed = fsaptr->table->table_type == DENSE;

  num_iterations = 0;
  /* The main refinement loop follows. */
  do {
    num_iterations++;
    ns_final = ns_new;
    /* Turn off excessive printing at this point */
    j = kbm_print_level;
    kbm_print_level = 1;
    hash_init(&ht, fixed, ne + 1, 0, 0);
    kbm_print_level = j;
    if (kbm_print_level >= 3)
      printf("    #Iterating - number of state categories = %d.\n", ns_new);
    block_numb[0] = 0;
    for (i = 1; i <= ns_orig; i++)
      if (acc || fsaptr->is_accessible[i]) {
        /* Insert the encoded form of the transitions from state i into the
         * hashtable preceded by the current block number of i.
         */
        len = fixed ? ne + 1 : table[i + 1] - table[i] + 1;
        ptr = ht.current_ptr;
        *ptr = block_numa[i];
        if (fixed) {
          for (j = 1; j < len; j++)
            ptr[j] = block_numa[table[j][i]];
          l = len;
        }
        else {
          l = 0;
          for (j = 1; j < len; j += 2) {
            k = block_numa[table[i][j]];
            if (k > 0) {
              ptr[++l] = table[i][j - 1];
              ptr[++l] = k;
            }
          }
          if (l > 0 || *ptr > 0)
            l++;
          /* For technical reasons, we want the zero record to be empty */
        }
        block_numb[i] = hash_locate(&ht, l);
        if (block_numb[i] == -1)
          return -1;
      }
      else
        block_numb[i] = 0;
    ns_new = ht.num_recs;
    block_swap = block_numa;
    block_numa = block_numb;
    block_numb = block_swap;
    if (ns_new > ns_final || num_iterations == 1)
      hash_clear(&ht);
  } while (ns_new > ns_final || num_iterations == 1);
  /* We must have at least two iterations, because the first time through
   * we have the lables rather than the states in the transition table.
   */

  /* At this stage, either ns_final = ns_new, or the fsa has empty accepted
   * language, ns_new=0 and ns_final=1.
   */

  fsaptr->flags[ACCESSIBLE] = TRUE;

  if (ns_new == 0) {
    /* This is the awkward case of no states - always causes problems! */
    fsaptr->states->size = 0;
    fsaptr->num_initial = 0;
    tfree(fsaptr->initial);
    fsaptr->num_accepting = 0;
    tfree(fsaptr->accepting);
    tfree(fsaptr->table->table_data_ptr[0]);
    tfree(fsaptr->table->table_data_ptr);
  }
  else if (ns_final < ns_orig) {
    /* Re-define the fsa fields  */
    fsaptr->states->size = ns_final;

    fsaptr->initial[1] = block_numa[fsaptr->initial[1]];

    for (i = 1; i <= ns_orig; i++)
      block_numb[block_numa[i]] = fsaptr->states->setToLabels[i];
    for (i = 1; i <= ns_final; i++)
      fsaptr->states->setToLabels[i] = block_numb[i];

    if (fsaptr->num_accepting == ns_orig) {
      fsaptr->num_accepting = ns_final;
      if (ns_final == 1) {
        tmalloc(fsaptr->accepting, int, 2);
        fsaptr->accepting[1] = 1;
      }
    }
    else {
      tmalloc(fsaptr->is_accepting, boolean, ns_final + 1);
      for (i = 1; i <= ns_final; i++)
        fsaptr->is_accepting[i] = FALSE;
      for (i = 1; i <= fsaptr->num_accepting; i++)
        fsaptr->is_accepting[block_numa[fsaptr->accepting[i]]] = TRUE;
      fsaptr->num_accepting = 0;
      for (i = 1; i <= ns_final; i++)
        if (fsaptr->is_accepting[i])
          fsaptr->num_accepting++;
      tfree(fsaptr->accepting);
      tmalloc(fsaptr->accepting, int, fsaptr->num_accepting + 1);
      j = 0;
      for (i = 1; i <= ns_final; i++)
        if (fsaptr->is_accepting[i])
          fsaptr->accepting[++j] = i;
      tfree(fsaptr->is_accepting);
    }

    /* Finally copy the transition table data from the hash-table back to the
     * fsa */
    tfree(fsaptr->table->table_data_ptr[0]);
    tfree(fsaptr->table->table_data_ptr);
    if (fixed) {
      fsa_table_init(fsaptr->table, ns_final, ne);
      table = fsaptr->table->table_data_ptr;
      for (i = 1; i <= ns_final; i++) {
        ht_ptr = hash_rec(&ht, i);
        for (j = 1; j <= ne; j++)
          table[j][i] = ht_ptr[j];
      }
    }
    else {
      tmalloc(fsaptr->table->table_data_ptr, int *, ns_final + 2);
      tmalloc(fsaptr->table->table_data_ptr[0], int, ht.tot_space - ns_final);
      table = fsaptr->table->table_data_ptr;
      table[1] = ptr = table[0];
      for (i = 1; i <= ns_final; i++) {
        ht_ptr = hash_rec(&ht, i);
        ptr2 = ht_ptr + 1;
        ptr2e = ht_ptr + hash_rec_len(&ht, i) - 1;
        while (ptr2 <= ptr2e)
          *(ptr++) = *(ptr2++);
        table[i + 1] = ptr;
      }
    }
  }
  hash_clear(&ht);
  tfree(block_numa);
  tfree(block_numb);
  tfree(fsaptr->is_accessible);
  if (kbm_print_level >= 3)
    printf("    #Number of iterations = %d.\n", num_iterations);
  return 0;
}


/* Put the fsa *fsapt into bfs form. */
int fsa_bfs(fsa *fsaptr)
{
  int ns, ne, *perm, *perminv, **table, ct, i, j, s, t;
  boolean *got, dense;

  if (fsaptr->table->table_type == SPARSE && fsaptr->table->denserows > 0) {
    fprintf(stderr,
            "Sorry: fsa_bfs unavailable for sparse storage with dense rows.\n");
    return -1;
  }
  if (kbm_print_level >= 3)
    printf("    #Calling fsa_bfs.\n");
  if (!fsaptr->flags[DFA]) {
    fprintf(stderr, "Error: fsa_bfs only applies to DFA's.\n");
    return -1;
  }
  if (fsaptr->flags[BFS])
    return 0;

  fsa_make_accessible(fsaptr);

  if (fsaptr->flags[RWS])
    fsa_clear_rws(fsaptr);

  ne = fsaptr->alphabet->size;
  ns = fsaptr->states->size;
  if (ns == 0)
    return 0;

  dense = fsaptr->table->table_type == DENSE;
  table = fsaptr->table->table_data_ptr;

  tmalloc(got, boolean, ns + 1);
  for (i = 1; i <= ns; i++)
    got[i] = FALSE;
  tmalloc(perm, int, ns + 1);
  perm[0] = 0;
  perm[1] = fsaptr->initial[1];
  got[perm[1]] = TRUE;
  ct = 1;
  i = 1;
  while (i <= ct) {
    s = perm[i];
    for (j = 1; j <= ne; j++) {
      t = target(dense, table, j, s, 0);
      if (t > 0 && !got[t]) {
        perm[++ct] = t;
        got[t] = TRUE;
      }
    }
    i++;
  }

  tfree(got);
  /* The inverse of perm is what is required */
  tmalloc(perminv, int, ns + 1);
  for (i = 0; i <= ns; i++)
    perminv[perm[i]] = i;
  tfree(perm);
  fsa_permute_states(fsaptr, perminv);
  tfree(perminv);
  fsaptr->flags[BFS] = TRUE;
  return 0;
}

/* Count the size of the accepted language of the fsa *fsaptr.
 * Return this size, or -2 if infinite.
 */
int fsa_count(fsa *fsaptr)
{
  int i, j, ct, ne, ns, **table, dr, *in_degree, *ordered_state_list,
      *num_acc_words, cstate, im;
  boolean dense;

  if (!fsaptr->flags[DFA]) {
    fprintf(stderr, "Error: fsa_count only applies to DFA's.\n");
    return -1;
  }
  if (!fsaptr->flags[TRIM])
    if (fsa_minimize(fsaptr) == -1)
      return -1;

  ne = fsaptr->alphabet->size;
  ns = fsaptr->states->size;
  if (ns == 0)
    return 0;

  dr = fsaptr->table->denserows;

  /* We first count the number of edges going into each state */
  tmalloc(in_degree, int, ns + 1);
  for (i = 1; i <= ns; i++)
    in_degree[i] = 0;
  dense = fsaptr->table->table_type == DENSE;
  table = fsaptr->table->table_data_ptr;
  for (i = 1; i <= ns; i++)
    for (j = 1; j <= ne; j++) {
      im = target(dense, table, j, i, dr);
      if (im > 0)
        in_degree[im]++;
    }

  /* Now we try to order the states so that if state s <= state t, then there
   * is no path from state t to state s. If this is not possible, then the
   * accepted language must be infinite.
   */
  cstate = fsaptr->initial[1];
  if (in_degree[cstate] > 0) {
    tfree(in_degree);
    return -2;
  }
  tmalloc(ordered_state_list, int, ns + 1);
  ordered_state_list[1] = cstate;

  ct = 1;
  i = 0;
  while (++i <= ct) {
    cstate = ordered_state_list[i];
    for (j = 1; j <= ne; j++) {
      im = target(dense, table, j, cstate, dr);
      if (im > 0) {
        in_degree[im]--;
        if (in_degree[im] == 0)
          ordered_state_list[++ct] = im;
      }
    }
  }

  if (ct != ns) {
    tfree(in_degree) tfree(ordered_state_list) return -2;
  }

  /* We have built the list, so the accepted language is finite. Now we work
   * backwards through the list, calculating the number of accepted words
   * starting at that state.
   * We might as well use the same space as was used by in_degree, which
   * is no longer needed.
   */
  fsa_set_is_accepting(fsaptr);
  num_acc_words = in_degree;
  for (i = ns; i >= 1; i--) {
    cstate = ordered_state_list[i];
    num_acc_words[cstate] = 0;
    for (j = 1; j <= ne; j++) {
      im = target(dense, table, j, cstate, dr);
      if (im > 0)
        num_acc_words[cstate] += num_acc_words[im];
    }
    if (fsaptr->is_accepting[cstate])
      num_acc_words[cstate]++;
  }

  ct = num_acc_words[fsaptr->initial[1]];
  tfree(in_degree) tfree(ordered_state_list)
      tfree(fsaptr->is_accepting) return ct;
}

/* Enumerate the subset of the language of the finite state automaton *fsaptr,
 * consisting of those words having length l satisfying min <= l <= max.
 * Since there is no point in storing these words currently, they are
 * printed out to the file wfile, with all but the last one to be printed
 * followed by a comma and carriage return.
 * 1 is returned if some words are found - otherwise 0.
 * If putcomma is true, then the first word to be printed is preceded by comma
 * and carriage-return (to handle the case when this function is called
 * repeatedly).
 * If stateno is 1, then the number of the accept state reched by an
 * accepted word is printed.
 * If stateno is 2, then fsaptr->states should have type 'labeled', and
 * the labels of the accept-states reached by the words are printed.
 */
int fsa_enumerate(FILE *wfile, fsa *fsaptr, int min, int max, boolean putcomma,
                  int stateno)
{
  int i, g1, g2, ne, ngens, ngens1 = 0, **table, dr, *cword, firste, clength,
      clength1, clength2, cstate, im, *statelist;
  boolean dense, done, backtrack, foundword, prod, numbers;
  gen *cword1 = 0, *cword2 = 0;
  char **names = 0;

  if (!fsaptr->flags[DFA]) {
    fprintf(stderr, "Error: fsa_enumerate only applies to DFA's.\n");
    return -1;
  }

  if (stateno == 2 && fsaptr->states->type != LABELED) {
    fprintf(stderr,
            "Error: in fsa_enumerate state-set must have type labeled.\n");
    return -1;
  }

  if (fsaptr->num_initial == 0)
    return 0;

  ne = fsaptr->alphabet->size;

  dr = fsaptr->table->denserows;

  dense = fsaptr->table->table_type == DENSE;
  table = fsaptr->table->table_data_ptr;

  tmalloc(cword, int, max + 1);
  /* to hold the current word in the enumeration */

  /* "names" will be used to store the symbols used for printing. If no natural
   * names are available, then we just use the numbers of the edges.
   */
  prod = fsaptr->alphabet->type == PRODUCT;
  if (prod) {
    if (fsaptr->alphabet->arity != 2) {
      fprintf(stderr,
              "Sorry  can only cope with two-variable product alphabets.\n");
      return 0;
    }
    ngens = fsaptr->alphabet->base->size;
    ngens1 = ngens + 1;
    numbers = fsaptr->alphabet->base->type == SIMPLE ||
              fsaptr->alphabet->base->type == LABELED ||
              fsaptr->alphabet->base->type == WORDS ||
              fsaptr->alphabet->base->type == LISTOFWORDS ||
              fsaptr->alphabet->base->type == LISTOFINTS;
    if (!numbers) {
      names = fsaptr->alphabet->base->names;
      tmalloc(names[ngens1], char, 2);
      strcpy(names[ngens1], "_");
    }
    tmalloc(cword1, gen, max + 1);
    tmalloc(cword2, gen, max + 1);
    /* These are used for the two components of the word cword =
     * [cword1,cword2].
     */
  }
  else {
    numbers = fsaptr->alphabet->type == SIMPLE ||
              fsaptr->alphabet->type == LABELED ||
              fsaptr->alphabet->type == WORDS ||
              fsaptr->alphabet->type == LISTOFWORDS ||
              fsaptr->alphabet->type == LISTOFINTS;
    if (!numbers)
      names = fsaptr->alphabet->names;
  }
  if (numbers) { /* define the integral names. */
    tmalloc(names, char *, ne + 1);
    for (i = 1; i <= ne; i++) {
      tmalloc(names[i], char, int_len(i) + 1);
      sprintf(names[i], "%d", i);
    }
  }

  *kbm_buffer = '\0';
  tmalloc(statelist, int, max + 1);
  /* this is used to store the state history on scanning the current word. */
  for (i = 0; i <= max; i++)
    cword[i] = 0;
  clength = 0;
  statelist[0] = fsaptr->initial[1];
  fsa_set_is_accepting(fsaptr);
  done = FALSE;
  foundword = FALSE;
  /* Backtrack search can now begin */
  while (!done) {
    /* first see if we want the current word - if so, print it */
    if (clength >= min && fsaptr->is_accepting[statelist[clength]]) {
      if (putcomma || foundword)
        fprintf(wfile, ",\n");
      if (stateno)
        add_to_buffer(0, "[");
      foundword = TRUE;
      if (prod) { /* split word into components and print them */
        clength1 = clength2 = 0;
        for (i = 0; i < clength; i++) {
          g1 = (cword[i] - 1) / ngens1 + 1;
          g2 = (cword[i] - 1) % ngens1 + 1;
          /*if (g1<ngens1)*/ cword1[clength1++] = g1;
          /*if (g2<ngens1)*/ cword2[clength2++] = g2;
        }
        cword1[clength1] = 0;
        cword2[clength2] = 0;
        add_to_buffer(0, " [");
        add_word_to_buffer(wfile, cword1, names);
        add_to_buffer(0, ",");
        add_word_to_buffer(wfile, cword2, names);
        add_to_buffer(0, "]");
      }
      else {
        add_to_buffer(0, " ");
        add_iword_to_buffer(wfile, cword, names);
      }
      if (stateno == 1)
        sprintf(kbm_buffer + stringlen(kbm_buffer), ",%d]", statelist[clength]);
      if (stateno == 2)
        sprintf(kbm_buffer + stringlen(kbm_buffer), ",%d]",
                fsaptr->states->setToLabels[statelist[clength]]);

      fprintf(wfile, "%s", kbm_buffer);
      *kbm_buffer = '\0';
    }
    /* Now proceed to next word in the search */
    firste = 1;
    backtrack = TRUE;
    while (backtrack && !done) {
      if (clength < max) {
        cstate = statelist[clength];
        i = firste - 1;
        while (backtrack && ++i <= ne)
          if ((im = target(dense, table, i, cstate, dr)) >
              0) { /* found next node */
            cword[clength++] = i;
            statelist[clength] = im;
            backtrack = FALSE;
          }
      }
      if (backtrack) {
        if (clength == 0)
          done = TRUE;
        else {
          firste = cword[--clength] + 1;
          cword[clength] = 0;
        }
      }
    }
  }

  if (numbers) {
    assert(names);
    for (i = 1; i <= ne; i++)
      tfree(names[i]);
    tfree(names);
  }
  tfree(fsaptr->is_accepting);
  tfree(cword);
  if (prod) {
    tfree(cword1);
    tfree(cword2);
  }
  tfree(statelist);

  return (int)foundword;
}

/* *fsaptr must be a two-variable fsa, in dense format. This routine
 * alters *fsaptr by swapping the variable. That is it replaces transitions
 * s - (a,b) -> t  by  s - (b,a) -> t, for a,b in the base-alphabet.
 */
int fsa_swap_coords(fsa *fsaptr)
{
  int ***dtable, ngens1, ns, g1, g2, st, st1, st2;

  if (kbm_print_level >= 3)
    printf("    #Calling fsa_swap_coords.\n");
  if (!fsaptr->flags[DFA]) {
    fprintf(stderr, "Error: fsa_swap_coords only applies to DFA's.\n");
    return -1;
  }

  if (fsaptr->alphabet->type != PRODUCT || fsaptr->alphabet->arity != 2) {
    fprintf(stderr, "Error in fsa_swap_coords: fsa must be 2-variable.\n");
    return -1;
  }

  if (fsaptr->table->table_type != DENSE) {
    fprintf(stderr, "Error: function fsa_swap_coords must be called with a "
                    "densely-stored fsa.\n");
    return -1;
  }

  fsaptr->flags[BFS] = FALSE;
  fsa_table_dptr_init(fsaptr);
  ns = fsaptr->states->size;
  ngens1 = fsaptr->alphabet->base->size + 1;
  dtable = fsaptr->table->table_data_dptr;

  for (st = 1; st <= ns; st++) {
    for (g1 = 1; g1 <= ngens1; g1++)
      for (g2 = 1; g2 < g1; g2++) {
        st1 = dense_dtarget(dtable, g1, g2, st);
        st2 = dense_dtarget(dtable, g2, g1, st);
        set_dense_dtarget(dtable, g1, g2, st, st2);
        set_dense_dtarget(dtable, g2, g1, st, st1);
      }
  }
  return 0;
}

/****************************************************************
 * NEW FSA STUFF - by  Laurent Bartholdi
 ****************************************************************/

/* fsa_mod_count() computes the number of elements of length i in the
   accepted language, for all 0 <= i <= n where n=#of states in fsa.
   All computations are mod. p
 */
unsigned *fsa_mod_count(fsa *fsaptr, unsigned p, unsigned num)
{
  unsigned *state_count, *new_count, *count, n, dr, i, j, k;
  int **table;
  boolean dense;

  if (!fsaptr->flags[DFA]) {
    fprintf(stderr, "Error: fsa_mod_count only applies to DFA's.\n");
    return 0;
  }
  if (!fsaptr->flags[TRIM]) {
    printf("#WARNING: fsa_mod_count applied to fsa not known to be trim.\n");
    printf("#It will be minimized before proceeding.\n");
    if (fsa_minimize(fsaptr) == -1)
      return 0;
  }

  n = fsaptr->states->size;
  dense = fsaptr->table->table_type == DENSE;
  table = fsaptr->table->table_data_ptr;
  dr = fsaptr->table->denserows;

  tmalloc(state_count, unsigned, n + 1); /* # of words ending at given state */
  tmalloc(new_count, unsigned,
          n + 1);                    /* new # of words ending at given state */
  tmalloc(count, unsigned, num + 1); /* the answer */

  for (i = 1; i <= n; i++)
    state_count[i] = 0;
  for (i = 1; i <= fsaptr->num_initial; i++)
    state_count[fsaptr->initial[i]]++;

  for (i = 0; i <= num; i++) {
    count[i] = 0;
    for (j = 1; j <= fsaptr->num_accepting; j++)
      count[i] =
          (count[i] +
           state_count[fsaptr->num_accepting == n ? j : fsaptr->accepting[j]]) %
          p;

    for (j = 1; j <= n; j++)
      new_count[j] = 0;
    for (j = 1; j <= n; j++)
      for (k = 1; k <= fsaptr->alphabet->size; k++) {
        int im = target(dense, table, k, j, dr);
        if (im > 0)
          new_count[im] = (new_count[im] + state_count[j]) % p;
      }
    for (j = 1; j <= n; j++)
      state_count[j] = new_count[j];
  }
  tfree(state_count);
  tfree(new_count);

  return count;
}

unsigned mod_inverse(unsigned i, unsigned p)
{
  unsigned m = i, n = p;
  int a = 1, b = 0, c = 0, d = 1;
  /* we have a*i+b*p = m, c*i+d*p = n at all times;
     further m<n */
  while (m != 0) {
    unsigned q = n / m, tm = m;
    int ta = a, tb = b;
    m = n - q * m, a = c - q * a, b = d - q * b;
    n = tm, c = ta, d = tb;
  }
  if (n != 1)
    fprintf(stderr, "In mod_inverse(): cannot compute");
  return (c + p) % p;
}

/* solve A*B=A[n] in n-dimensional matrices and vectors, mod. p.
   the return value is the smallest possible size of B,
   or -1 if the computation could not be performed. */
int mod_solve(int **A, int *B, unsigned p, unsigned n)
{
  unsigned degree = n;
  int i, j, k;

  for (i = 0; i < n; i++) { /* clean up the ith column */
    int inv, pivot = -1;
    for (j = i; j < n; j++)
      if (A[j][i] != 0) {
        pivot = j;
        break;
      }
    if (pivot < 0) { /* oops... singular matrix ? */
      for (j = i; j < n; j++)
        if (A[j][n] != 0) {
          fprintf(stderr, "In mod_solve(): Singular matrix\n");
          return -1;
        }
      degree = i;
      break;
    }
    if (A[i][i] == 0)
      for (j = i; j <= n; j++)
        A[i][j] = (A[i][j] + A[pivot][j]) % p;
    inv = mod_inverse(A[i][i], p);
    for (j = i; j <= n; j++)
      A[i][j] = (A[i][j] * inv) % p;
    for (j = i + 1; j < n; j++)
      for (k = n; k >= i; k--)
        A[j][k] = (A[j][k] + (p - A[j][i]) * A[i][k]) % p;
  }

  for (i = degree - 1; i >= 0; i--) {
    B[i] = A[i][n];
    for (j = 0; j < i; j++) {
      A[j][n] = (A[j][n] + (p - A[j][i]) * A[i][n]) % p;
      A[j][i] = 0;
    }
  }
  return degree;
}

int fsa_mod_growth(fsa *fsaptr, fraction *f, unsigned p)
{
  unsigned *count, n, i, j;
  int **A;

  n = fsaptr->states->size;
  tmalloc(A, int *, n);
  for (i = 0; i < n; i++)
    tmalloc(A[i], int, n + 1);
  tmalloc(f->num, int, n + 1);
  tmalloc(f->den, int, n + 1);

  count = fsa_mod_count(fsaptr, p, 2 * n);
  if (count == 0)
    return -1;
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++)
      A[i][j] = count[n + i - j];
    A[i][n] = (p - count[i + n + 1]) % p;
  }
  f->den[0] = 1;
  f->dd = mod_solve(A, f->den + 1, p, n);

  for (i = 0; i <= n; i++)
    f->num[i] = 0;
  for (i = 0; i <= n; i++)
    for (j = 0; j <= f->dd && i + j <= n; j++)
      f->num[i + j] = (f->num[i + j] + count[i] * f->den[j]) % p;
  for (i = n;; i--)
    if (f->num[i] != 0) {
      f->nd = i;
      break;
    };

  for (i = 0; i < n; i++)
    tfree(A[i]);
  tfree(A);
  return 0;
}

void mod_normal(int *poly, unsigned d, unsigned p)
{
  int i;
  for (i = 0; i <= d; i++) {
    poly[i] %= p;
    if (poly[i] < 0)
      poly[i] += p;
    if (poly[i] > p / 2)
      poly[i] -= p;
  }
}

/* Edited by dfh to buffer printing and insert new-lines
 * returns true if it prints a new line, otherwise false.
 */
boolean print_poly(FILE *f, int *poly, unsigned d, char *var)
{
  boolean first = TRUE, ans = FALSE;
  int i, bufflen;

  bufflen = strlen(kbm_buffer);
  for (i = 0; i <= d; i++)
    if (poly[i] != 0) {
      if (first) {
        if (poly[i] > 0 && (i == 0 || poly[i] > 1))
          sprintf(kbm_buffer + strlen(kbm_buffer), "%d", poly[i]);
        else if (poly[i] < 0 && (i == 0 || poly[i] < -1))
          sprintf(kbm_buffer + strlen(kbm_buffer), "%d", poly[i]);
        else if (poly[i] == -1)
          sprintf(kbm_buffer + strlen(kbm_buffer), "-");
      }
      else {
        if (poly[i] > 1)
          sprintf(kbm_buffer + strlen(kbm_buffer), " + %d", poly[i]);
        else if (poly[i] < -1)
          sprintf(kbm_buffer + strlen(kbm_buffer), " - %d", -poly[i]);
        else if (poly[i] == 1)
          sprintf(kbm_buffer + strlen(kbm_buffer), " + ");
        else if (poly[i] == -1)
          sprintf(kbm_buffer + strlen(kbm_buffer), " - ");
      }
      if (i >= 1) {
        if (poly[i] == 1 || poly[i] == -1)
          sprintf(kbm_buffer + strlen(kbm_buffer), "%s", var);
        else
          sprintf(kbm_buffer + strlen(kbm_buffer), "*%s", var);
      }
      if (i >= 2)
        sprintf(kbm_buffer + strlen(kbm_buffer), "^%d", i);
      if (strlen(kbm_buffer) > 66 && i < d) {
        printbuffer(f);
        add_to_buffer(bufflen + 1, "");
        ans = TRUE;
      }
      first = FALSE;
    }
  if (first)
    fprintf(f, "0");
  return ans;
}

/*
void
print_poly(FILE *f, int *poly, unsigned d, char *var)
{
  boolean first = TRUE;
  int i;

  for (i = 0; i <= d; i++)
  if (poly[i] != 0) {
    if (first) {
      if (poly[i] > 0) fprintf(f,"%d", poly[i]);
      else fprintf(f,"-%d", -poly[i]);
    } else {
      if (poly[i] > 0) fprintf(f," + %d", poly[i]);
      else fprintf(f," - %d", -poly[i]);
    }
    if (i >= 1) fprintf(f,"*%s", var);
    if (i >= 2) fprintf(f,"^%d", i);

    first = FALSE;
  }
  if (first) fprintf(f,"0");
}
*/

int fsa_growth(FILE *wfile, fsa *fsaptr, unsigned *primes, char *var)
{
  boolean cr;
  fraction f = {0,0,0,0}, newf;
  int i;
  boolean consistent = TRUE;
  boolean printres;
  boolean firstprime = TRUE;

  while (*primes) {
    printres = FALSE;
    fprintf(wfile, "#result modulo prime %d:", *primes);
    if (kbm_print_level >= 2)
      printf("  #Computing growth modulo %d\n", *primes);

    if (fsa_mod_growth(fsaptr, &newf, *primes) == -1)
      return -1;
    mod_normal(newf.den, newf.dd, *primes);
    mod_normal(newf.num, newf.nd, *primes);
    if (firstprime) {
      f = newf;
      printres = TRUE;
      fprintf(wfile, "\n");
    }
    else if (f.dd != newf.dd || f.nd != newf.nd) {
      tfree(f.num);
      tfree(f.den);
      f = newf;
      consistent = FALSE;
      printres = TRUE;
    }
    else {
      boolean fixup = FALSE;
      for (i = 0; i <= newf.dd; i++)
        if (newf.den[i] != f.den[i]) {
          fixup = TRUE;
          f.den[i] = newf.den[i];
        }
      for (i = 0; i <= newf.nd; i++)
        if (newf.num[i] != f.num[i]) {
          fixup = TRUE;
          f.num[i] = newf.num[i];
        }
      if (fixup) {
        consistent = FALSE;
        printres = TRUE;
      }
      tfree(newf.num);
      tfree(newf.den);
    }
    if (printres) {
      if (firstprime)
        firstprime = FALSE;
      else
        fprintf(wfile, "\n");
      sprintf(kbm_buffer + strlen(kbm_buffer), "(");
      cr = print_poly(wfile, f.num, f.nd, var);
      sprintf(kbm_buffer + strlen(kbm_buffer), ")/");
      if (cr || strlen(kbm_buffer) >= 40)
        printbuffer(wfile);
      sprintf(kbm_buffer + strlen(kbm_buffer), "(");
      cr = print_poly(wfile, f.den, f.dd, var);
      sprintf(kbm_buffer + strlen(kbm_buffer), ");");
      printbuffer(wfile);
    }
    else
      fprintf(wfile, " (as previous)\n");
    primes++;
  }
  if (kbm_print_level >= 2) {
    int m = 0;
    for (i = 0; i <= f.nd; i++)
      if (f.num[i] > m)
        m = f.num[i];
      else if (f.num[i] < -m)
        m = -f.num[i];
    for (i = 0; i <= f.dd; i++)
      if (f.den[i] > m)
        m = f.den[i];
      else if (f.den[i] < -m)
        m = -f.den[i];
    printf("  #Degrees %d/%d, Max coefficient %d\n", f.nd, f.dd, m);
  }
  tfree(f.den);
  tfree(f.num);
  return (int)consistent;
}