/**
  @file

  @ingroup cudd

  @brief Export functions.

  @author Fabio Somenzi

  @copyright@parblock
  Copyright (c) 1995-2015, Regents of the University of Colorado

  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:

  Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.

  Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.

  Neither the name of the University of Colorado nor the names of its
  contributors may be used to endorse or promote products derived from
  this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
  @endparblock

*/

#include "util.h"
#include "cstringstream.h"
#include "cuddInt.h"

/*---------------------------------------------------------------------------*/
/* Constant declarations                                                     */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Stucture declarations                                                     */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Type declarations                                                         */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Variable declarations                                                     */
/*---------------------------------------------------------------------------*/


/*---------------------------------------------------------------------------*/
/* Macro declarations                                                        */
/*---------------------------------------------------------------------------*/

/** \cond */

/*---------------------------------------------------------------------------*/
/* Static function prototypes                                                */
/*---------------------------------------------------------------------------*/

static int ddDoDumpBlif (DdManager *dd, DdNode *f, FILE *fp, st_table *visited, char const * const *names, int mv);
static int ddDoDumpDaVinci (DdManager *dd, DdNode *f, FILE *fp, st_table *visited, char const * const *names, ptruint mask);
static int ddDoDumpDDcal (DdManager *dd, DdNode *f, FILE *fp, st_table *visited, char const * const *names, ptruint mask);
static int ddDoDumpFactoredForm (DdManager *dd, DdNode *f, FILE *fp, char const * const *names);
static int ddDoFactoredFormString(DdManager * dd, DdNode *f, cstringstream stream, char const * const * names);
/** \endcond */


/*---------------------------------------------------------------------------*/
/* Definition of exported functions                                          */
/*---------------------------------------------------------------------------*/


/**
  @brief Writes a blif file representing the argument BDDs.

  @details Each %BDD is written as a network of multiplexers.
  Cudd_DumpBlif does not close the file: This is the caller
  responsibility. Cudd_DumpBlif uses a minimal unique subset of the
  hexadecimal address of a node as name for it.  If the argument
  inames is non-null, it is assumed to hold the pointers to the names
  of the inputs. Similarly for onames.

  @return 1 in case of success; 0 otherwise (e.g., out-of-memory, file
  system full, or an %ADD with constants different from 0 and 1).

  @sideeffect None

  @see Cudd_DumpBlifBody Cudd_DumpDot Cudd_PrintDebug Cudd_DumpDDcal
  Cudd_DumpDaVinci Cudd_DumpFactoredForm

*/
int
Cudd_DumpBlif(
  DdManager * dd /**< manager */,
  int  n /**< number of output nodes to be dumped */,
  DdNode ** f /**< array of output nodes to be dumped */,
  char const * const * inames /**< array of input names (or NULL) */,
  char const * const * onames /**< array of output names (or NULL) */,
  char * mname /**< model name (or NULL) */,
  FILE * fp /**< pointer to the dump file */,
  int mv /**< 0: blif, 1: blif-MV */)
{
    DdNode	*support = NULL;
    DdNode	*scan;
    int		*sorted = NULL;
    int		nvars = dd->size;
    int		retval;
    int		i;

    /* Build a bit array with the support of f. */
    sorted = ALLOC(int,nvars);
    if (sorted == NULL) {
	dd->errorCode = CUDD_MEMORY_OUT;
	goto failure;
    }
    for (i = 0; i < nvars; i++) sorted[i] = 0;

    /* Take the union of the supports of each output function. */
    support = Cudd_VectorSupport(dd,f,n);
    if (support == NULL) goto failure;
    cuddRef(support);
    scan = support;
    while (!cuddIsConstant(scan)) {
	sorted[scan->index] = 1;
	scan = cuddT(scan);
    }
    Cudd_RecursiveDeref(dd,support);
    support = NULL; /* so that we do not try to free it in case of failure */

    /* Write the header (.model .inputs .outputs). */
    if (mname == NULL) {
	retval = fprintf(fp,".model DD\n.inputs");
    } else {
	retval = fprintf(fp,".model %s\n.inputs",mname);
    }
    if (retval == EOF) {
	FREE(sorted);
	return(0);
    }

    /* Write the input list by scanning the support array. */
    for (i = 0; i < nvars; i++) {
	if (sorted[i]) {
	    if (inames == NULL) {
		retval = fprintf(fp," %d", i);
	    } else {
		retval = fprintf(fp," %s", inames[i]);
	    }
	    if (retval == EOF) goto failure;
	}
    }
    FREE(sorted);
    sorted = NULL;

    /* Write the .output line. */
    retval = fprintf(fp,"\n.outputs");
    if (retval == EOF) goto failure;
    for (i = 0; i < n; i++) {
	if (onames == NULL) {
	    retval = fprintf(fp," f%d", i);
	} else {
	    retval = fprintf(fp," %s", onames[i]);
	}
	if (retval == EOF) goto failure;
    }
    retval = fprintf(fp,"\n");
    if (retval == EOF) goto failure;

    retval = Cudd_DumpBlifBody(dd, n, f, inames, onames, fp, mv);
    if (retval == 0) goto failure;

    /* Write trailer and return. */
    retval = fprintf(fp,".end\n");
    if (retval == EOF) goto failure;

    return(1);

 failure:
    if (sorted != NULL) FREE(sorted);
    if (support != NULL) Cudd_RecursiveDeref(dd,support);
    return(0);

} /* end of Cudd_DumpBlif */


/**
  @brief Writes a blif body representing the argument BDDs.

  @details Each %BDD is written as a network of multiplexers.  No
  header (.model, .inputs, and .outputs) and footer (.end) are
  produced by this function.  One multiplexer is written for each %BDD
  node.  Cudd_DumpBlifBody does not close the file: This is the caller
  responsibility. Cudd_DumpBlifBody uses a minimal unique subset of
  the hexadecimal address of a node as name for it.  If the argument
  inames is non-null, it is assumed to hold the pointers to the names
  of the inputs. Similarly for onames. This function prints out only
  .names part.

  @return 1 in case of success; 0 otherwise (e.g., out-of-memory, file
  system full, or an %ADD with constants different from 0 and 1).

  @sideeffect None

  @see Cudd_DumpBlif Cudd_DumpDot Cudd_PrintDebug Cudd_DumpDDcal
  Cudd_DumpDaVinci Cudd_DumpFactoredForm

*/
int
Cudd_DumpBlifBody(
  DdManager * dd /**< manager */,
  int  n /**< number of output nodes to be dumped */,
  DdNode ** f /**< array of output nodes to be dumped */,
  char const * const * inames /**< array of input names (or NULL) */,
  char const * const * onames /**< array of output names (or NULL) */,
  FILE * fp /**< pointer to the dump file */,
  int mv /**< 0: blif, 1: blif-MV */)
{
    st_table	*visited = NULL;
    int		retval;
    int		i;

    /* Initialize symbol table for visited nodes. */
    visited = st_init_table(st_ptrcmp, st_ptrhash);
    if (visited == NULL) goto failure;

    /* Call the function that really gets the job done. */
    for (i = 0; i < n; i++) {
	retval = ddDoDumpBlif(dd,Cudd_Regular(f[i]),fp,visited,inames,mv);
	if (retval == 0) goto failure;
    }

    /* To account for the possible complement on the root,
    ** we put either a buffer or an inverter at the output of
    ** the multiplexer representing the top node.
    */
    for (i = 0; i < n; i++) {
	if (onames == NULL) {
	    retval = fprintf(fp, ".names %" PRIxPTR " f%d\n",
                (ptruint) f[i] / (ptruint) sizeof(DdNode), i);
	} else {
	    retval = fprintf(fp, ".names %" PRIxPTR " %s\n",
                (ptruint) f[i] / (ptruint) sizeof(DdNode), onames[i]);
	}
	if (retval == EOF) goto failure;
	if (Cudd_IsComplement(f[i])) {
	    retval = fprintf(fp,"%s0 1\n", mv ? ".def 0\n" : "");
	} else {
	    retval = fprintf(fp,"%s1 1\n", mv ? ".def 0\n" : "");
	}
	if (retval == EOF) goto failure;
    }

    st_free_table(visited);
    return(1);

 failure:
    if (visited != NULL) st_free_table(visited);
    return(0);

} /* end of Cudd_DumpBlifBody */


/**
  @brief Writes a dot file representing the argument DDs.

  @details Writes a file representing the argument DDs in a format
  suitable for the graph drawing program dot.
  Cudd_DumpDot does not close the file: This is the caller
  responsibility. Cudd_DumpDot uses a minimal unique subset of the
  hexadecimal address of a node as name for it.
  If the argument inames is non-null, it is assumed to hold the pointers
  to the names of the inputs. Similarly for onames.
  Cudd_DumpDot uses the following convention to draw arcs:
    <ul>
    <li> solid line: THEN arcs;
    <li> dotted line: complement arcs;
    <li> dashed line: regular ELSE arcs.
    </ul>
  The dot options are chosen so that the drawing fits on a letter-size
  sheet.

  @return 1 in case of success; 0 otherwise (e.g., out-of-memory, file
  system full).

  @sideeffect None

  @see Cudd_DumpBlif Cudd_PrintDebug Cudd_DumpDDcal
  Cudd_DumpDaVinci Cudd_DumpFactoredForm

*/
int
Cudd_DumpDot(
  DdManager * dd /**< manager */,
  int  n /**< number of output nodes to be dumped */,
  DdNode ** f /**< array of output nodes to be dumped */,
  char const * const * inames /**< array of input names (or NULL) */,
  char const * const * onames /**< array of output names (or NULL) */,
  FILE * fp /**< pointer to the dump file */)
{
    DdNode	*support = NULL;
    DdNode	*scan;
    int		*sorted = NULL;
    int		nvars = dd->size;
    st_table	*visited = NULL;
    st_generator *gen = NULL;
    int		retval;
    int		i, j;
    int		slots;
    DdNodePtr	*nodelist;
    ptruint	refAddr, diff, mask = 0;

    /* Build a bit array with the support of f. */
    sorted = ALLOC(int,nvars);
    if (sorted == NULL) {
	dd->errorCode = CUDD_MEMORY_OUT;
	goto failure;
    }
    for (i = 0; i < nvars; i++) sorted[i] = 0;

    /* Take the union of the supports of each output function. */
    support = Cudd_VectorSupport(dd,f,n);
    if (support == NULL) goto failure;
    cuddRef(support);
    scan = support;
    while (!cuddIsConstant(scan)) {
	sorted[scan->index] = 1;
	scan = cuddT(scan);
    }
    Cudd_RecursiveDeref(dd,support);
    support = NULL; /* so that we do not try to free it in case of failure */

    /* Initialize symbol table for visited nodes. */
    visited = st_init_table(st_ptrcmp, st_ptrhash);
    if (visited == NULL) goto failure;

    /* Collect all the nodes of this DD in the symbol table. */
    for (i = 0; i < n; i++) {
	retval = cuddCollectNodes(Cudd_Regular(f[i]),visited);
	if (retval == 0) goto failure;
    }

    /* Find how many most significant hex digits are identical
    ** in the addresses of all the nodes. Build a mask based
    ** on this knowledge, so that digits that carry no information
    ** will not be printed. This is done in two steps.
    **  1. We scan the symbol table to find the bits that differ
    **     in at least 2 addresses.
    **  2. We choose one of the possible masks. There are 8 possible
    **     masks for 32-bit integer, and 16 possible masks for 64-bit
    **     integers.
    */

    /* Find the bits that are different. */
    refAddr = (ptruint) Cudd_Regular(f[0]);
    diff = 0;
    gen = st_init_gen(visited);
    if (gen == NULL) goto failure;
    while (st_gen(gen, (void **) &scan, NULL)) {
	diff |= refAddr ^ (ptruint) scan;
    }
    st_free_gen(gen); gen = NULL;

    /* Choose the mask. */
    for (i = 0; (unsigned) i < 8 * sizeof(ptruint); i += 4) {
        mask = ((ptruint) 1 << i) - 1;
	if (diff <= mask) break;
    }

    /* Write the header and the global attributes. */
    retval = fprintf(fp,"digraph \"DD\" {\n");
    if (retval == EOF) return(0);
    retval = fprintf(fp,
	"size = \"7.5,10\"\ncenter = true;\nedge [dir = none];\n");
    if (retval == EOF) return(0);

    /* Write the input name subgraph by scanning the support array. */
    retval = fprintf(fp,"{ node [shape = plaintext];\n");
    if (retval == EOF) goto failure;
    retval = fprintf(fp,"  edge [style = invis];\n");
    if (retval == EOF) goto failure;
    /* We use a name ("CONST NODES") with an embedded blank, because
    ** it is unlikely to appear as an input name.
    */
    retval = fprintf(fp,"  \"CONST NODES\" [style = invis];\n");
    if (retval == EOF) goto failure;
    for (i = 0; i < nvars; i++) {
	if (sorted[dd->invperm[i]]) {
	    if (inames == NULL || inames[dd->invperm[i]] == NULL) {
		retval = fprintf(fp,"\" %d \" -> ", dd->invperm[i]);
	    } else {
		retval = fprintf(fp,"\" %s \" -> ", inames[dd->invperm[i]]);
	    }
	    if (retval == EOF) goto failure;
	}
    }
    retval = fprintf(fp,"\"CONST NODES\"; \n}\n");
    if (retval == EOF) goto failure;

    /* Write the output node subgraph. */
    retval = fprintf(fp,"{ rank = same; node [shape = box]; edge [style = invis];\n");
    if (retval == EOF) goto failure;
    for (i = 0; i < n; i++) {
	if (onames == NULL) {
	    retval = fprintf(fp,"\"F%d\"", i);
	} else {
	    retval = fprintf(fp,"\"  %s  \"", onames[i]);
	}
	if (retval == EOF) goto failure;
	if (i == n - 1) {
	    retval = fprintf(fp,"; }\n");
	} else {
	    retval = fprintf(fp," -> ");
	}
	if (retval == EOF) goto failure;
    }

    /* Write rank info: All nodes with the same index have the same rank. */
    for (i = 0; i < nvars; i++) {
	if (sorted[dd->invperm[i]]) {
	    retval = fprintf(fp,"{ rank = same; ");
	    if (retval == EOF) goto failure;
	    if (inames == NULL || inames[dd->invperm[i]] == NULL) {
		retval = fprintf(fp,"\" %d \";\n", dd->invperm[i]);
	    } else {
		retval = fprintf(fp,"\" %s \";\n", inames[dd->invperm[i]]);
	    }
	    if (retval == EOF) goto failure;
	    nodelist = dd->subtables[i].nodelist;
	    slots = dd->subtables[i].slots;
	    for (j = 0; j < slots; j++) {
		scan = nodelist[j];
		while (scan != NULL) {
		    if (st_is_member(visited,scan)) {
			retval = fprintf(fp,"\"%#" PRIxPTR "\";\n",
			    ((mask & (ptruint) scan) / sizeof(DdNode)));
			if (retval == EOF) goto failure;
		    }
		    scan = scan->next;
		}
	    }
	    retval = fprintf(fp,"}\n");
	    if (retval == EOF) goto failure;
	}
    }

    /* All constants have the same rank. */
    retval = fprintf(fp,
	"{ rank = same; \"CONST NODES\";\n{ node [shape = box]; ");
    if (retval == EOF) goto failure;
    nodelist = dd->constants.nodelist;
    slots = dd->constants.slots;
    for (j = 0; j < slots; j++) {
	scan = nodelist[j];
	while (scan != NULL) {
	    if (st_is_member(visited,scan)) {
		retval = fprintf(fp,"\"%#" PRIxPTR "\";\n",
		    ((mask & (ptruint) scan) / sizeof(DdNode)));
		if (retval == EOF) goto failure;
	    }
	    scan = scan->next;
	}
    }
    retval = fprintf(fp,"}\n}\n");
    if (retval == EOF) goto failure;

    /* Write edge info. */
    /* Edges from the output nodes. */
    for (i = 0; i < n; i++) {
	if (onames == NULL) {
	    retval = fprintf(fp,"\"F%d\"", i);
	} else {
	    retval = fprintf(fp,"\"  %s  \"", onames[i]);
	}
	if (retval == EOF) goto failure;
	/* Account for the possible complement on the root. */
	if (Cudd_IsComplement(f[i])) {
	    retval = fprintf(fp," -> \"%#" PRIxPTR "\" [style = dotted];\n",
		((mask & (ptruint) f[i]) / sizeof(DdNode)));
	} else {
	    retval = fprintf(fp," -> \"%#" PRIxPTR "\" [style = solid];\n",
		((mask & (ptruint) f[i]) / sizeof(DdNode)));
	}
	if (retval == EOF) goto failure;
    }

    /* Edges from internal nodes. */
    for (i = 0; i < nvars; i++) {
	if (sorted[dd->invperm[i]]) {
	    nodelist = dd->subtables[i].nodelist;
	    slots = dd->subtables[i].slots;
	    for (j = 0; j < slots; j++) {
		scan = nodelist[j];
		while (scan != NULL) {
		    if (st_is_member(visited,scan)) {
			retval = fprintf(fp,
			    "\"%#" PRIxPTR "\" -> \"%#" PRIxPTR "\";\n",
			    ((mask & (ptruint) scan) / sizeof(DdNode)),
			    ((mask & (ptruint) cuddT(scan)) / sizeof(DdNode)));
			if (retval == EOF) goto failure;
			if (Cudd_IsComplement(cuddE(scan))) {
			    retval = fprintf(fp,
				"\"%#" PRIxPTR "\" -> \"%#" PRIxPTR
                                             "\" [style = dotted];\n",
				((mask & (ptruint) scan) / sizeof(DdNode)),
				((mask & (ptruint) cuddE(scan)) /
				sizeof(DdNode)));
			} else {
			    retval = fprintf(fp,
				"\"%#" PRIxPTR "\" -> \"%#" PRIxPTR
                                             "\" [style = dashed];\n",
				((mask & (ptruint) scan) / sizeof(DdNode)),
				((mask & (ptruint) cuddE(scan)) /
				sizeof(DdNode)));
			}
			if (retval == EOF) goto failure;
		    }
		    scan = scan->next;
		}
	    }
	}
    }

    /* Write constant labels. */
    nodelist = dd->constants.nodelist;
    slots = dd->constants.slots;
    for (j = 0; j < slots; j++) {
	scan = nodelist[j];
	while (scan != NULL) {
	    if (st_is_member(visited,scan)) {
		retval = fprintf(fp,"\"%#" PRIxPTR "\" [label = \"%g\"];\n",
		    ((mask & (ptruint) scan) / sizeof(DdNode)), cuddV(scan));
		if (retval == EOF) goto failure;
	    }
	    scan = scan->next;
	}
    }

    /* Write trailer and return. */
    retval = fprintf(fp,"}\n");
    if (retval == EOF) goto failure;

    st_free_table(visited);
    FREE(sorted);
    return(1);

 failure:
    if (sorted != NULL) FREE(sorted);
    if (support != NULL) Cudd_RecursiveDeref(dd,support);
    if (visited != NULL) st_free_table(visited);
    return(0);

} /* end of Cudd_DumpDot */


/**
  @brief Writes a daVinci file representing the argument BDDs.

  @details Writes a daVinci file representing the argument BDDs.
  Cudd_DumpDaVinci does not close the file: This is the caller
  responsibility. Cudd_DumpDaVinci uses a minimal unique subset of the
  hexadecimal address of a node as name for it.  If the argument
  inames is non-null, it is assumed to hold the pointers to the names
  of the inputs. Similarly for onames.

  @return 1 in case of success; 0 otherwise (e.g., out-of-memory or
  file system full).

  @sideeffect None

  @see Cudd_DumpDot Cudd_PrintDebug Cudd_DumpBlif Cudd_DumpDDcal
  Cudd_DumpFactoredForm

*/
int
Cudd_DumpDaVinci(
  DdManager * dd /**< manager */,
  int  n /**< number of output nodes to be dumped */,
  DdNode ** f /**< array of output nodes to be dumped */,
  char const * const * inames /**< array of input names (or NULL) */,
  char const * const * onames /**< array of output names (or NULL) */,
  FILE * fp /**< pointer to the dump file */)
{
    DdNode	  *support = NULL;
    DdNode	  *scan;
    st_table	  *visited = NULL;
    int		  retval;
    int		  i;
    st_generator  *gen;
    ptruint       refAddr, diff, mask = 0;

    /* Initialize symbol table for visited nodes. */
    visited = st_init_table(st_ptrcmp, st_ptrhash);
    if (visited == NULL) goto failure;

    /* Collect all the nodes of this DD in the symbol table. */
    for (i = 0; i < n; i++) {
	retval = cuddCollectNodes(Cudd_Regular(f[i]),visited);
	if (retval == 0) goto failure;
    }

    /* Find how many most significant hex digits are identical
    ** in the addresses of all the nodes. Build a mask based
    ** on this knowledge, so that digits that carry no information
    ** will not be printed. This is done in two steps.
    **  1. We scan the symbol table to find the bits that differ
    **     in at least 2 addresses.
    **  2. We choose one of the possible masks. There are 8 possible
    **     masks for 32-bit integer, and 16 possible masks for 64-bit
    **     integers.
    */

    /* Find the bits that are different. */
    refAddr = (ptruint) Cudd_Regular(f[0]);
    diff = 0;
    gen = st_init_gen(visited);
    while (st_gen(gen, (void **) &scan, NULL)) {
	diff |= refAddr ^ (ptruint) scan;
    }
    st_free_gen(gen);

    /* Choose the mask. */
    for (i = 0; (unsigned) i < 8 * sizeof(ptruint); i += 4) {
	mask = ((ptruint) 1 << i) - 1;
	if (diff <= mask) break;
    }
    st_free_table(visited);

    /* Initialize symbol table for visited nodes. */
    visited = st_init_table(st_ptrcmp, st_ptrhash);
    if (visited == NULL) goto failure;

    retval = fprintf(fp, "[");
    if (retval == EOF) goto failure;
    /* Call the function that really gets the job done. */
    for (i = 0; i < n; i++) {
	if (onames == NULL) {
	    retval = fprintf(fp,
			     "l(\"f%d\",n(\"root\",[a(\"OBJECT\",\"f%d\")],",
			     i,i);
	} else {
	    retval = fprintf(fp,
			     "l(\"%s\",n(\"root\",[a(\"OBJECT\",\"%s\")],",
			     onames[i], onames[i]);
	}
	if (retval == EOF) goto failure;
	retval = fprintf(fp, "[e(\"edge\",[a(\"EDGECOLOR\",\"%s\"),a(\"_DIR\",\"none\")],",
			 Cudd_IsComplement(f[i]) ? "red" : "blue");
	if (retval == EOF) goto failure;
	retval = ddDoDumpDaVinci(dd,Cudd_Regular(f[i]),fp,visited,inames,mask);
	if (retval == 0) goto failure;
	retval = fprintf(fp, ")]))%s", i == n-1 ? "" : ",");
	if (retval == EOF) goto failure;
    }

    /* Write trailer and return. */
    retval = fprintf(fp, "]\n");
    if (retval == EOF) goto failure;

    st_free_table(visited);
    return(1);

failure:
    if (support != NULL) Cudd_RecursiveDeref(dd,support);
    if (visited != NULL) st_free_table(visited);
    return(0);

} /* end of Cudd_DumpDaVinci */


/**
  @brief Writes a DDcal file representing the argument BDDs.

  @details Writes a DDcal file representing the argument BDDs.
  Cudd_DumpDDcal does not close the file: This is the caller
  responsibility. Cudd_DumpDDcal uses a minimal unique subset of the
  hexadecimal address of a node as name for it.  If the argument
  inames is non-null, it is assumed to hold the pointers to the names
  of the inputs. Similarly for onames.

  @return 1 in case of success; 0 otherwise (e.g., out-of-memory or
  file system full).

  @sideeffect None

  @see Cudd_DumpDot Cudd_PrintDebug Cudd_DumpBlif Cudd_DumpDaVinci
  Cudd_DumpFactoredForm

*/
int
Cudd_DumpDDcal(
  DdManager * dd /**< manager */,
  int  n /**< number of output nodes to be dumped */,
  DdNode ** f /**< array of output nodes to be dumped */,
  char const * const * inames /**< array of input names (or NULL) */,
  char const * const * onames /**< array of output names (or NULL) */,
  FILE * fp /**< pointer to the dump file */)
{
    DdNode	  *support = NULL;
    DdNode	  *scan;
    int		  *sorted = NULL;
    int		  nvars = dd->size;
    st_table	  *visited = NULL;
    int		  retval;
    int		  i;
    st_generator  *gen;
    ptruint       refAddr, diff, mask = 0;

    /* Initialize symbol table for visited nodes. */
    visited = st_init_table(st_ptrcmp, st_ptrhash);
    if (visited == NULL) goto failure;

    /* Collect all the nodes of this DD in the symbol table. */
    for (i = 0; i < n; i++) {
	retval = cuddCollectNodes(Cudd_Regular(f[i]),visited);
	if (retval == 0) goto failure;
    }

    /* Find how many most significant hex digits are identical
    ** in the addresses of all the nodes. Build a mask based
    ** on this knowledge, so that digits that carry no information
    ** will not be printed. This is done in two steps.
    **  1. We scan the symbol table to find the bits that differ
    **     in at least 2 addresses.
    **  2. We choose one of the possible masks. There are 8 possible
    **     masks for 32-bit integer, and 16 possible masks for 64-bit
    **     integers.
    */

    /* Find the bits that are different. */
    refAddr = (ptruint) Cudd_Regular(f[0]);
    diff = 0;
    gen = st_init_gen(visited);
    while (st_gen(gen, (void **) &scan, NULL)) {
	diff |= refAddr ^ (ptruint) scan;
    }
    st_free_gen(gen);

    /* Choose the mask. */
    for (i = 0; (unsigned) i < 8 * sizeof(ptruint); i += 4) {
	mask = ((ptruint) 1 << i) - 1;
	if (diff <= mask) break;
    }
    st_free_table(visited);

    /* Build a bit array with the support of f. */
    sorted = ALLOC(int,nvars);
    if (sorted == NULL) {
	dd->errorCode = CUDD_MEMORY_OUT;
	goto failure;
    }
    for (i = 0; i < nvars; i++) sorted[i] = 0;

    /* Take the union of the supports of each output function. */
    support = Cudd_VectorSupport(dd,f,n);
    if (support == NULL) goto failure;
    cuddRef(support);
    scan = support;
    while (!cuddIsConstant(scan)) {
	sorted[scan->index] = 1;
	scan = cuddT(scan);
    }
    Cudd_RecursiveDeref(dd,support);
    support = NULL; /* so that we do not try to free it in case of failure */
    for (i = 0; i < nvars; i++) {
	if (sorted[dd->invperm[i]]) {
	    if (inames == NULL || inames[dd->invperm[i]] == NULL) {
		retval = fprintf(fp,"v%d", dd->invperm[i]);
	    } else {
		retval = fprintf(fp,"%s", inames[dd->invperm[i]]);
	    }
	    if (retval == EOF) goto failure;
	}
	retval = fprintf(fp,"%s", i == nvars - 1 ? "\n" : " * ");
	if (retval == EOF) goto failure;
    }
    FREE(sorted);
    sorted = NULL;

    /* Initialize symbol table for visited nodes. */
    visited = st_init_table(st_ptrcmp, st_ptrhash);
    if (visited == NULL) goto failure;

    /* Call the function that really gets the job done. */
    for (i = 0; i < n; i++) {
	retval = ddDoDumpDDcal(dd,Cudd_Regular(f[i]),fp,visited,inames,mask);
	if (retval == 0) goto failure;
	if (onames == NULL) {
	    retval = fprintf(fp, "f%d = ", i);
	} else {
	    retval = fprintf(fp, "%s = ", onames[i]);
	}
	if (retval == EOF) goto failure;
	retval = fprintf(fp, "n%#" PRIxPTR "%s\n",
			 (((ptruint) f[i] & mask) / sizeof(DdNode)),
			 Cudd_IsComplement(f[i]) ? "'" : "");
	if (retval == EOF) goto failure;
    }

    /* Write trailer and return. */
    retval = fprintf(fp, "[");
    if (retval == EOF) goto failure;
    for (i = 0; i < n; i++) {
	if (onames == NULL) {
	    retval = fprintf(fp, "f%d", i);
	} else {
	    retval = fprintf(fp, "%s", onames[i]);
	}
	if (retval == EOF) goto failure;
	retval = fprintf(fp, "%s", i == n-1 ? "" : " ");
	if (retval == EOF) goto failure;
    }
    retval = fprintf(fp, "]\n");
    if (retval == EOF) goto failure;

    st_free_table(visited);
    return(1);

failure:
    if (sorted != NULL) FREE(sorted);
    if (support != NULL) Cudd_RecursiveDeref(dd,support);
    if (visited != NULL) st_free_table(visited);
    return(0);

} /* end of Cudd_DumpDDcal */


/**
  @brief Writes factored forms representing the argument BDDs.

  @details Writes factored forms representing the argument BDDs.  The
  format of the factored form is the one used in the genlib files for
  technology mapping in sis.  Cudd_DumpFactoredForm does not close the
  file: This is the caller responsibility. Caution must be exercised
  because a factored form may be exponentially larger than the
  argument %BDD.  If the argument inames is non-null, it is assumed to
  hold the pointers to the names of the inputs. Similarly for onames.
  If the number of output nodes is 0, it is interpreted as 1, but no
  output name followed by equal sign is printed before the factored
  form.

  @return 1 in case of success; 0 otherwise (e.g., file system full).

  @sideeffect None

  @see Cudd_DumpDot Cudd_PrintDebug Cudd_DumpBlif Cudd_DumpDaVinci
  Cudd_DumpDDcal

*/
int
Cudd_DumpFactoredForm(
  DdManager * dd /**< manager */,
  int  n /**< number of output nodes to be dumped */,
  DdNode ** f /**< array of output nodes to be dumped */,
  char const * const * inames /**< array of input names (or NULL) */,
  char const * const * onames /**< array of output names (or NULL) */,
  FILE * fp /**< pointer to the dump file */)
{
    int		retval = 0;
    int		i;
    int		printName = n != 0;

    if (!printName) n = 1;

    /* Call the function that really gets the job done. */
    for (i = 0; i < n; i++) {
        if (printName) {
            if (onames == NULL) {
		retval = fprintf(fp, "f%d = ", i);
            } else {
		retval = fprintf(fp, "%s = ", onames[i]);
            }
        }
	if (retval == EOF) return(0);
	if (f[i] == DD_ONE(dd)) {
	    retval = fprintf(fp, "CONST1");
	    if (retval == EOF) return(0);
	} else if (f[i] == Cudd_Not(DD_ONE(dd)) || f[i] == DD_ZERO(dd)) {
	    retval = fprintf(fp, "CONST0");
	    if (retval == EOF) return(0);
	} else {
	    retval = fprintf(fp, "%s", Cudd_IsComplement(f[i]) ? (Cudd_bddIsVar(dd, Cudd_Regular(f[i])) ? "!" : "!(") : "");
	    if (retval == EOF) return(0);
	    retval = ddDoDumpFactoredForm(dd,Cudd_Regular(f[i]),fp,inames);
	    if (retval == 0) return(0);
	    retval = fprintf(fp, "%s", Cudd_IsComplement(f[i]) && !Cudd_bddIsVar(dd, Cudd_Regular(f[i])) ? ")" : "");
	    if (retval == EOF) return(0);
	}
	retval = fprintf(fp, "%s", i == n-1 ? "" : "\n");
	if (retval == EOF) return(0);
    }

    return(1);

} /* end of Cudd_DumpFactoredForm */


/**
  @brief Returns a string with the factored form of the argument BDDs

  @details The factored form uses & for conjunction, | for disjunction
  and ! for negation.  Caution must be exercised because a factored
  form may be exponentially larger than the argument %BDD.  If the
  argument inames is non-null, it is assumed to hold the pointers to
  the names of the inputs.

  @return a string in case of success; NULL otherwise.

  @sideeffect None

  @see Cudd_DumpDot Cudd_PrintDebug Cudd_DumpBlif Cudd_DumpDaVinci
  Cudd_DumpDDcal Cudd_DumpFactoredForm

*/
char *
Cudd_FactoredFormString(
  DdManager *dd,
  DdNode *f,
  char const * const * inames)
{
    cstringstream stream = newStringStream();
    int err, retval;
    char * str;

    if (!stream) {
        return(0);
    }
    /* Call the function that really gets the job done. */
    if (f == DD_ONE(dd)) {
        err = appendStringStringStream(stream, "true");
        if (err) {
            deleteStringStream(stream);
            return(0);
        }
    } else if (f == Cudd_Not(DD_ONE(dd)) || f == DD_ZERO(dd)) {
        err = appendStringStringStream(stream, "false");
        if (err) {
            deleteStringStream(stream);
            return(0);
        }
    } else {
        err = appendStringStringStream(
          stream, Cudd_IsComplement(f) ?
          (Cudd_bddIsVar(dd, Cudd_Regular(f)) ? "!" : "!(") : "");
        if (err) {
            deleteStringStream(stream);
            return(0);
        }
        retval = ddDoFactoredFormString(dd,Cudd_Regular(f),stream,inames);
        if (retval == 0) {
            deleteStringStream(stream);
            return(0);
        }
        err = appendStringStringStream(
          stream, Cudd_IsComplement(f) &&
          !Cudd_bddIsVar(dd, Cudd_Regular(f)) ? ")" : "");
        if (err) {
            deleteStringStream(stream);
            return(0);
        }
    }
    str = stringFromStringStream(stream);
    deleteStringStream(stream);
    return(str);

} /* end of Cudd_FactoredFormString */


/*---------------------------------------------------------------------------*/
/* Definition of internal functions                                          */
/*---------------------------------------------------------------------------*/


/*---------------------------------------------------------------------------*/
/* Definition of static functions                                            */
/*---------------------------------------------------------------------------*/


/**
  @brief Performs the recursive step of Cudd_DumpBlif.

  @details Traverses the %BDD f and writes a multiplexer-network
  description to the file pointed by fp in blif format. f is assumed
  to be a regular pointer and ddDoDumpBlif guarantees this assumption
  in the recursive calls.

  @sideeffect None

*/
static int
ddDoDumpBlif(
  DdManager * dd,
  DdNode * f,
  FILE * fp,
  st_table * visited,
  char const * const * names,
  int mv)
{
    DdNode	*T, *E;
    int		retval;

#ifdef DD_DEBUG
    assert(!Cudd_IsComplement(f));
#endif

    /* If already visited, nothing to do. */
    if (st_is_member(visited, f) == 1)
	return(1);

    /* Check for abnormal condition that should never happen. */
    if (f == NULL)
	return(0);

    /* Mark node as visited. */
    if (st_insert(visited, f, NULL) == ST_OUT_OF_MEM)
	return(0);

    /* Check for special case: If constant node, generate constant 1. */
    if (f == DD_ONE(dd)) {
	retval = fprintf(fp, ".names %" PRIxPTR "\n1\n",(ptruint) f / (ptruint) sizeof(DdNode));
	if (retval == EOF) {
	    return(0);
	} else {
	    return(1);
	}
    }

    /* Check whether this is an ADD. We deal with 0-1 ADDs, but not
    ** with the general case.
    */
    if (f == DD_ZERO(dd)) {
	retval = fprintf(fp, ".names %" PRIxPTR "\n%s",
			 (ptruint) f / (ptruint) sizeof(DdNode),
			 mv ? "0\n" : "");
	if (retval == EOF) {
	    return(0);
	} else {
	    return(1);
	}
    }
    if (cuddIsConstant(f))
	return(0);

    /* Recursive calls. */
    T = cuddT(f);
    retval = ddDoDumpBlif(dd,T,fp,visited,names,mv);
    if (retval != 1) return(retval);
    E = Cudd_Regular(cuddE(f));
    retval = ddDoDumpBlif(dd,E,fp,visited,names,mv);
    if (retval != 1) return(retval);

    /* Write multiplexer taking complement arc into account. */
    if (names != NULL) {
	retval = fprintf(fp,".names %s", names[f->index]);
    } else {
#if SIZEOF_VOID_P == 8 && SIZEOF_INT == 4
	retval = fprintf(fp,".names %u", f->index);
#else
	retval = fprintf(fp,".names %hu", f->index);
#endif
    }
    if (retval == EOF)
	return(0);

    if (mv) {
	if (Cudd_IsComplement(cuddE(f))) {
	    retval = fprintf(fp," %" PRIxPTR " %" PRIxPTR " %" PRIxPTR "\n.def 0\n1 1 - 1\n0 - 0 1\n",
		(ptruint) T / (ptruint) sizeof(DdNode),
		(ptruint) E / (ptruint) sizeof(DdNode),
		(ptruint) f / (ptruint) sizeof(DdNode));
	} else {
	    retval = fprintf(fp," %" PRIxPTR " %" PRIxPTR " %" PRIxPTR "\n.def 0\n1 1 - 1\n0 - 1 1\n",
		(ptruint) T / (ptruint) sizeof(DdNode),
		(ptruint) E / (ptruint) sizeof(DdNode),
		(ptruint) f / (ptruint) sizeof(DdNode));
	}
    } else {
	if (Cudd_IsComplement(cuddE(f))) {
	    retval = fprintf(fp," %" PRIxPTR " %" PRIxPTR " %" PRIxPTR "\n11- 1\n0-0 1\n",
		(ptruint) T / (ptruint) sizeof(DdNode),
		(ptruint) E / (ptruint) sizeof(DdNode),
		(ptruint) f / (ptruint) sizeof(DdNode));
	} else {
	    retval = fprintf(fp," %" PRIxPTR " %" PRIxPTR " %" PRIxPTR "\n11- 1\n0-1 1\n",
		(ptruint) T / (ptruint) sizeof(DdNode),
		(ptruint) E / (ptruint) sizeof(DdNode),
		(ptruint) f / (ptruint) sizeof(DdNode));
	}
    }
    if (retval == EOF) {
	return(0);
    } else {
	return(1);
    }

} /* end of ddDoDumpBlif */


/**
  @brief Performs the recursive step of Cudd_DumpDaVinci.

  @details Traverses the %BDD f and writes a term expression to the
  file pointed by fp in daVinci format. f is assumed to be a regular
  pointer and ddDoDumpDaVinci guarantees this assumption in the
  recursive calls.

  @sideeffect None

*/
static int
ddDoDumpDaVinci(
  DdManager * dd,
  DdNode * f,
  FILE * fp,
  st_table * visited,
  char const * const * names,
  ptruint mask)
{
    DdNode  *T, *E;
    int	    retval;
    ptruint id;

#ifdef DD_DEBUG
    assert(!Cudd_IsComplement(f));
#endif

    id = ((ptruint) f & mask) / sizeof(DdNode);

    /* If already visited, insert a reference. */
    if (st_is_member(visited, f) == 1) {
	retval = fprintf(fp,"r(\"%#" PRIxPTR "\")", id);
	if (retval == EOF) {
	    return(0);
	} else {
	    return(1);
	}
    }

    /* Check for abnormal condition that should never happen. */
    if (f == NULL)
	return(0);

    /* Mark node as visited. */
    if (st_insert(visited, f, NULL) == ST_OUT_OF_MEM)
	return(0);

    /* Check for special case: If constant node, generate constant 1. */
    if (Cudd_IsConstantInt(f)) {
	retval = fprintf(fp,
			 "l(\"%#" PRIxPTR
                         "\",n(\"constant\",[a(\"OBJECT\",\"%g\")],[]))",
			 id, cuddV(f));
	if (retval == EOF) {
	    return(0);
	} else {
	    return(1);
	}
    }

    /* Recursive calls. */
    if (names != NULL) {
	retval = fprintf(fp, "l(\"%#" PRIxPTR
                         "\",n(\"internal\",[a(\"OBJECT\",\"%s\"),",
			 id, names[f->index]);
    } else {
#if SIZEOF_VOID_P == 8
	retval = fprintf(fp, "l(\"%#" PRIxPTR
                         "\",n(\"internal\",[a(\"OBJECT\",\"%u\"),",
			 id, f->index);
#else
	retval = fprintf(fp, "l(\"%#"PRIxPTR
                         "\",n(\"internal\",[a(\"OBJECT\",\"%hu\"),",
			 id, f->index);
#endif
    }
    if (retval == EOF) return(0);
    retval = fprintf(fp, "a(\"_GO\",\"ellipse\")],[e(\"then\",[a(\"EDGECOLOR\",\"blue\"),a(\"_DIR\",\"none\")],");
    if (retval == EOF) return(0);
    T = cuddT(f);
    retval = ddDoDumpDaVinci(dd,T,fp,visited,names,mask);
    if (retval != 1) return(retval);
    retval = fprintf(fp, "),e(\"else\",[a(\"EDGECOLOR\",\"%s\"),a(\"_DIR\",\"none\")],",
		     Cudd_IsComplement(cuddE(f)) ? "red" : "green");
    if (retval == EOF) return(0);
    E = Cudd_Regular(cuddE(f));
    retval = ddDoDumpDaVinci(dd,E,fp,visited,names,mask);
    if (retval != 1) return(retval);

    retval = fprintf(fp,")]))");
    if (retval == EOF) {
	return(0);
    } else {
	return(1);
    }

} /* end of ddDoDumpDaVinci */


/**
  @brief Performs the recursive step of Cudd_DumpDDcal.

  @details Traverses the %BDD f and writes a line for each node to the
  file pointed by fp in DDcal format. f is assumed to be a regular
  pointer and ddDoDumpDDcal guarantees this assumption in the
  recursive calls.

  @sideeffect None

*/
static int
ddDoDumpDDcal(
  DdManager * dd,
  DdNode * f,
  FILE * fp,
  st_table * visited,
  char const * const * names,
  ptruint mask)
{
    DdNode  *T, *E;
    int	    retval;
    ptruint id, idT, idE;

#ifdef DD_DEBUG
    assert(!Cudd_IsComplement(f));
#endif

    id = ((ptruint) f & mask) / sizeof(DdNode);

    /* If already visited, do nothing. */
    if (st_is_member(visited, f) == 1) {
	return(1);
    }

    /* Check for abnormal condition that should never happen. */
    if (f == NULL)
	return(0);

    /* Mark node as visited. */
    if (st_insert(visited, f, NULL) == ST_OUT_OF_MEM)
	return(0);

    /* Check for special case: If constant node, assign constant. */
    if (Cudd_IsConstantInt(f)) {
	if (f != DD_ONE(dd) && f != DD_ZERO(dd))
	    return(0);
	retval = fprintf(fp, "n%#" PRIxPTR" = %g\n", id, cuddV(f));
	if (retval == EOF) {
	    return(0);
	} else {
	    return(1);
	}
    }

    /* Recursive calls. */
    T = cuddT(f);
    retval = ddDoDumpDDcal(dd,T,fp,visited,names,mask);
    if (retval != 1) return(retval);
    E = Cudd_Regular(cuddE(f));
    retval = ddDoDumpDDcal(dd,E,fp,visited,names,mask);
    if (retval != 1) return(retval);
    idT = ((ptruint) T & mask) / sizeof(DdNode);
    idE = ((ptruint) E & mask) / sizeof(DdNode);
    if (names != NULL) {
	retval = fprintf(fp, "n%#" PRIxPTR " = %s * n%#" PRIxPTR
                         " + %s' * n%#" PRIxPTR "%s\n",
			 id, names[f->index], idT, names[f->index],
			 idE, Cudd_IsComplement(cuddE(f)) ? "'" : "");
    } else {
#if SIZEOF_VOID_P == 8
	retval = fprintf(fp, "n%#" PRIxPTR " = v%u * n%#" PRIxPTR
                         " + v%u' * n%#" PRIxPTR "%s\n",
			 id, f->index, idT, f->index,
			 idE, Cudd_IsComplement(cuddE(f)) ? "'" : "");
#else
	retval = fprintf(fp, "n%#"PRIxPTR" = v%hu * n%#"PRIxPTR
                         " + v%hu' * n%#"PRIxPTR"%s\n",
			 id, f->index, idT, f->index,
			 idE, Cudd_IsComplement(cuddE(f)) ? "'" : "");
#endif
    }
    if (retval == EOF) {
	return(0);
    } else {
	return(1);
    }

} /* end of ddDoDumpDDcal */


/**
  @brief Performs the recursive step of Cudd_DumpFactoredForm.

  @details Traverses the %BDD f and writes a factored form for each
  node to the file pointed by fp in terms of the factored forms of the
  children. Constants are propagated, and absorption is applied.  f is
  assumed to be a regular pointer and ddDoDumpFActoredForm guarantees
  this assumption in the recursive calls.

  @sideeffect None

  @see Cudd_DumpFactoredForm

*/
static int
ddDoDumpFactoredForm(
  DdManager * dd,
  DdNode * f,
  FILE * fp,
  char const * const * names)
{
    DdNode	*T, *E;
    int		retval;

#ifdef DD_DEBUG
    assert(!Cudd_IsComplement(f));
    assert(!cuddIsConstant(f));
#endif

    /* Check for abnormal condition that should never happen. */
    if (f == NULL)
	return(0);

    /* Recursive calls. */
    T = cuddT(f);
    E = cuddE(f);
    if (T != DD_ZERO(dd)) {
	if (E != DD_ONE(dd)) {
	    if (names != NULL) {
		retval = fprintf(fp, "%s", names[f->index]);
	    } else {
#if SIZEOF_VOID_P == 8 && SIZEOF_INT == 4
		retval = fprintf(fp, "x%u", f->index);
#else
		retval = fprintf(fp, "x%hu", f->index);
#endif
	    }
	    if (retval == EOF) return(0);
	}
	if (T != DD_ONE(dd)) {
            //	    retval = fprintf(fp, "%s(", E != DD_ONE(dd) ? " * " : "");
            retval = fprintf(fp, "%s%s", E != DD_ONE(dd) ? " * " : "", Cudd_bddIsVar(dd, T) ? "" : "(");
	    if (retval == EOF) return(0);
	    retval = ddDoDumpFactoredForm(dd,T,fp,names);
	    if (retval != 1) return(retval);
	    retval = fprintf(fp, "%s", Cudd_bddIsVar(dd, T) ? "" : ")");
	    if (retval == EOF) return(0);
	}
	if (E == Cudd_Not(DD_ONE(dd)) || E == DD_ZERO(dd)) return(1);
	retval = fprintf(fp, " + ");
	if (retval == EOF) return(0);
    }
    E = Cudd_Regular(E);
    if (T != DD_ONE(dd)) {
	if (names != NULL) {
	    retval = fprintf(fp, "!%s", names[f->index]);
	} else {
#if SIZEOF_VOID_P == 8 && SIZEOF_INT == 4
	    retval = fprintf(fp, "!x%u", f->index);
#else
	    retval = fprintf(fp, "!x%hu", f->index);
#endif
	}
	if (retval == EOF) return(0);
    }
    if (E != DD_ONE(dd)) {
	retval = fprintf(fp, "%s%s%s", T != DD_ONE(dd) ? " * " : "",
			 E != cuddE(f) ? "!" : "", Cudd_bddIsVar(dd, E) ? "" : "(");
	if (retval == EOF) return(0);
	retval = ddDoDumpFactoredForm(dd,E,fp,names);
	if (retval != 1) return(retval);
	retval = fprintf(fp, "%s", Cudd_bddIsVar(dd, E) ? "" : "(");
	if (retval == EOF) return(0);
    }
    return(1);

} /* end of ddDoDumpFactoredForm */


/**
  @brief Performs the recursive step of Cudd_DumpFactoredForm.

  @details Traverses the %BDD f and writes a factored form for each
  node to the file pointed by fp in terms of the factored forms of the
  children. Constants are propagated, and absorption is applied.  f is
  assumed to be a regular pointer and ddDoDumpFActoredForm guarantees
  this assumption in the recursive calls.

  @sideeffect None

  @see Cudd_DumpFactoredForm

*/
static int
ddDoFactoredFormString(
  DdManager * dd,
  DdNode * f,
  cstringstream stream,
  char const * const * names)
{
    DdNode	*T, *E;
    int		retval, err;

#ifdef DD_DEBUG
    assert(!Cudd_IsComplement(f));
    assert(!cuddIsConstant(f));
#endif

    /* Check for abnormal condition that should never happen. */
    if (f == NULL)
	return(0);

    /* Recursive calls. */
    T = cuddT(f);
    E = cuddE(f);
    if (T != DD_ZERO(dd)) {
	if (E != DD_ONE(dd)) {
	    if (names != NULL) {
                err = appendStringStringStream(stream, names[f->index]);
	    } else {
                err = appendCharStringStream(stream, 'x');
                if (err) return(0);
                err = appendUnsignedStringStream(stream, (unsigned) f->index);
	    }
	    if (err) return(0);
	}
	if (T != DD_ONE(dd)) {
            err = appendStringStringStream(stream, E != DD_ONE(dd) ? " & " : "");
            if (err) return(0);
            err = appendStringStringStream(stream, Cudd_bddIsVar(dd, T) ? "" : "(");
	    if (err) return(0);
	    retval = ddDoFactoredFormString(dd,T,stream,names);
	    if (retval != 1) return(retval);
            err = appendStringStringStream(stream, Cudd_bddIsVar(dd, T) ? "" : ")");
	    if (err) return(0);
	}
	if (E == Cudd_Not(DD_ONE(dd)) || E == DD_ZERO(dd)) return(1);
        err = appendStringStringStream(stream,  " | ");
	if (err) return(0);
    }
    E = Cudd_Regular(E);
    if (T != DD_ONE(dd)) {
        err = appendCharStringStream(stream, '!');
        if (err) return(0);
	if (names != NULL) {
            err = appendStringStringStream(stream, names[f->index]);
	} else {
            err = appendCharStringStream(stream, 'x');
            if (err) return(0);
            err = appendUnsignedStringStream(stream, (unsigned) f->index);
	}
	if (err) return(0);
    }
    if (E != DD_ONE(dd)) {
        err = appendStringStringStream(stream, T != DD_ONE(dd) ? " & " : "");
        if (err) return(0);
        err = appendStringStringStream(stream, E != cuddE(f) ? "!" : "");
        if (err) return(0);
        err = appendStringStringStream(stream, Cudd_bddIsVar(dd, E) ? "" : "(");
        if (err) return(0);
	retval = ddDoFactoredFormString(dd,E,stream,names);
	if (retval != 1) return(retval);
        err = appendStringStringStream(stream, Cudd_bddIsVar(dd, E) ? "" : ")");
	if (err) return(0);
    }
    return(1);

} /* end of ddDoFactoredFormString */