/**CFile***********************************************************************

  FileName    [mtrGroup.c]

  PackageName [mtr]

  Synopsis    [Functions to support group specification for reordering.]

  Description [External procedures included in this module:
	    <ul>
	    <li> Mtr_InitGroupTree()
	    <li> Mtr_MakeGroup()
	    <li> Mtr_DissolveGroup()
	    <li> Mtr_FindGroup()
	    <li> Mtr_SwapGroups()
	    <li> Mtr_PrintGroups()
	    <li> Mtr_ReadGroups()
	    </ul>
	Static procedures included in this module:
	    <ul>
	    <li> mtrShiftHL
	    </ul>
	    ]

  SeeAlso     [cudd package]

  Author      [Fabio Somenzi]

  Copyright   [This file was created at the University of Colorado at
  Boulder.  The University of Colorado at Boulder makes no warranty
  about the suitability of this software for any purpose.  It is
  presented on an AS IS basis.]

******************************************************************************/

#include "util.h"
#include "mtrInt.h"

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

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

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

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

#ifndef lint
static char rcsid[] MTR_UNUSED =
	"$Id: mtrGroup.c,v 1.14 2001/03/19 01:25:55 fabio Exp $";
#endif

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

/**AutomaticStart*************************************************************/

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

static int mtrShiftHL ARGS( ( MtrNode * node, int shift ) );

/**AutomaticEnd***************************************************************/

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


/**Function********************************************************************

  Synopsis    [Allocate new tree.]

  Description [Allocate new tree with one node, whose low and size
  fields are specified by the lower and size parameters.
  Returns pointer to tree root.]

  SideEffects [None]

  SeeAlso     [Mtr_InitTree Mtr_FreeTree]

******************************************************************************/
MtrNode *
Mtr_InitGroupTree( int lower, int size )
{
	MtrNode *root;

	root = Mtr_InitTree(  );
	if ( root == NULL )
		return ( NULL );
	root->flags = MTR_DEFAULT;
	root->low = lower;
	root->size = size;
	return ( root );

}								/* end of Mtr_InitGroupTree */


/**Function********************************************************************

  Synopsis    [Makes a new group with size leaves starting at low.]

  Description [Makes a new group with size leaves starting at low.
  If the new group intersects an existing group, it must
  either contain it or be contained by it.  This procedure relies on
  the low and size fields of each node. It also assumes that the
  children of each node are sorted in order of increasing low.  In
  case of a valid request, the flags of the new group are set to the
  value passed in `flags.' This can also be used to change the flags
  of an existing group.  Returns the pointer to the root of the new
  group upon successful termination; NULL otherwise. If the group
  already exists, the pointer to its root is returned.]

  SideEffects [None]

  SeeAlso     [Mtr_DissolveGroup Mtr_ReadGroups Mtr_FindGroup]

******************************************************************************/
MtrNode *
Mtr_MakeGroup( MtrNode * root /* root of the group tree */ ,
			   unsigned int low /* lower bound of the group */ ,
			   unsigned int size /* upper bound of the group */ ,
			   unsigned int flags /* flags for the new group */  )
{
	MtrNode *node, *first, *last, *previous, *newn;

	/* Sanity check. */
	if ( size == 0 )
		return ( NULL );

	/* Check whether current group includes new group.  This check is
	   ** necessary at the top-level call.  In the subsequent calls it is
	   ** redundant. */
	if ( low < ( unsigned int ) root->low ||
		 low + size > ( unsigned int ) ( root->low + root->size ) )
		return ( NULL );

	/* Trying to create an existing group has the effect of updating
	   ** the flags. */
	if ( root->size == size && root->low == low )
	{
		root->flags = flags;
		return ( root );
	}

	/* At this point we know that the new group is properly contained
	   ** in the group of root. We have two possible cases here: - root
	   ** is a terminal node; - root has children. */

	/* Root has no children: create a new group. */
	if ( root->child == NULL )
	{
		newn = Mtr_AllocNode(  );
		if ( newn == NULL )
			return ( NULL );	/* out of memory */
		newn->low = low;
		newn->size = size;
		newn->flags = flags;
		newn->parent = root;
		newn->elder = newn->younger = newn->child = NULL;
		root->child = newn;
		return ( newn );
	}

	/* Root has children: Find all chidren of root that are included
	   ** in the new group. If the group of any child entirely contains
	   ** the new group, call Mtr_MakeGroup recursively. */
	previous = NULL;
	first = root->child;		/* guaranteed to be non-NULL */
	while ( first != NULL
			&& low >= ( unsigned int ) ( first->low + first->size ) )
	{
		previous = first;
		first = first->younger;
	}
	if ( first == NULL )
	{
		/* We have scanned the entire list and we need to append a new
		   ** child at the end of it.  Previous points to the last child
		   ** of root. */
		newn = Mtr_AllocNode(  );
		if ( newn == NULL )
			return ( NULL );	/* out of memory */
		newn->low = low;
		newn->size = size;
		newn->flags = flags;
		newn->parent = root;
		newn->elder = previous;
		previous->younger = newn;
		newn->younger = newn->child = NULL;
		return ( newn );
	}
	/* Here first is non-NULL and low < first->low + first->size. */
	if ( low >= ( unsigned int ) first->low &&
		 low + size <= ( unsigned int ) ( first->low + first->size ) )
	{
		/* The new group is contained in the group of first. */
		newn = Mtr_MakeGroup( first, low, size, flags );
		return ( newn );
	}
	else if ( low + size <= first->low )
	{
		/* The new group is entirely contained in the gap between
		   ** previous and first. */
		newn = Mtr_AllocNode(  );
		if ( newn == NULL )
			return ( NULL );	/* out of memory */
		newn->low = low;
		newn->size = size;
		newn->flags = flags;
		newn->child = NULL;
		newn->parent = root;
		newn->elder = previous;
		newn->younger = first;
		first->elder = newn;
		if ( previous != NULL )
		{
			previous->younger = newn;
		}
		else
		{
			root->child = newn;
		}
		return ( newn );
	}
	else if ( low < ( unsigned int ) first->low &&
			  low + size < ( unsigned int ) ( first->low + first->size ) )
	{
		/* Trying to cut an existing group: not allowed. */
		return ( NULL );
	}
	else if ( low > first->low )
	{
		/* The new group neither is contained in the group of first
		   ** (this was tested above) nor contains it. It is therefore
		   ** trying to cut an existing group: not allowed. */
		return ( NULL );
	}

	/* First holds the pointer to the first child contained in the new
	   ** group. Here low <= first->low and low + size >= first->low +
	   ** first->size.  One of the two inequalities is strict. */
	last = first->younger;
	while ( last != NULL &&
			( unsigned int ) ( last->low + last->size ) < low + size )
	{
		last = last->younger;
	}
	if ( last == NULL )
	{
		/* All the chilren of root from first onward become children
		   ** of the new group. */
		newn = Mtr_AllocNode(  );
		if ( newn == NULL )
			return ( NULL );	/* out of memory */
		newn->low = low;
		newn->size = size;
		newn->flags = flags;
		newn->child = first;
		newn->parent = root;
		newn->elder = previous;
		newn->younger = NULL;
		first->elder = NULL;
		if ( previous != NULL )
		{
			previous->younger = newn;
		}
		else
		{
			root->child = newn;
		}
		last = first;
		while ( last != NULL )
		{
			last->parent = newn;
			last = last->younger;
		}
		return ( newn );
	}

	/* Here last != NULL and low + size <= last->low + last->size. */
	if ( low + size - 1 >= ( unsigned int ) last->low &&
		 low + size < ( unsigned int ) ( last->low + last->size ) )
	{
		/* Trying to cut an existing group: not allowed. */
		return ( NULL );
	}

	/* First and last point to the first and last of the children of
	   ** root that are included in the new group. Allocate a new node
	   ** and make all children of root between first and last chidren of
	   ** the new node.  Previous points to the child of root immediately
	   ** preceeding first. If it is NULL, then first is the first child
	   ** of root. */
	newn = Mtr_AllocNode(  );
	if ( newn == NULL )
		return ( NULL );		/* out of memory */
	newn->low = low;
	newn->size = size;
	newn->flags = flags;
	newn->child = first;
	newn->parent = root;
	if ( previous == NULL )
	{
		root->child = newn;
	}
	else
	{
		previous->younger = newn;
	}
	newn->elder = previous;
	newn->younger = last->younger;
	if ( last->younger != NULL )
	{
		last->younger->elder = newn;
	}
	last->younger = NULL;
	first->elder = NULL;
	for ( node = first; node != NULL; node = node->younger )
	{
		node->parent = newn;
	}

	return ( newn );

}								/* end of Mtr_MakeGroup */


/**Function********************************************************************

  Synopsis    [Merges the children of `group' with the children of its
  parent.]

  Description [Merges the children of `group' with the children of its
  parent. Disposes of the node pointed by group. If group is the
  root of the group tree, this procedure leaves the tree unchanged.
  Returns the pointer to the parent of `group' upon successful
  termination; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [Mtr_MakeGroup]

******************************************************************************/
MtrNode *
Mtr_DissolveGroup( MtrNode * group /* group to be dissolved */  )
{
	MtrNode *parent;
	MtrNode *last;

	parent = group->parent;

	if ( parent == NULL )
		return ( NULL );
	if ( MTR_TEST( group, MTR_TERMINAL ) || group->child == NULL )
		return ( NULL );

	/* Make all children of group children of its parent, and make
	   ** last point to the last child of group. */
	for ( last = group->child; last->younger != NULL; last = last->younger )
	{
		last->parent = parent;
	}
	last->parent = parent;

	last->younger = group->younger;
	if ( group->younger != NULL )
	{
		group->younger->elder = last;
	}

	group->child->elder = group->elder;
	if ( group == parent->child )
	{
		parent->child = group->child;
	}
	else
	{
		group->elder->younger = group->child;
	}

	Mtr_DeallocNode( group );
	return ( parent );

}								/* end of Mtr_DissolveGroup */


/**Function********************************************************************

  Synopsis [Finds a group with size leaves starting at low, if it exists.]

  Description [Finds a group with size leaves starting at low, if it
  exists.  This procedure relies on the low and size fields of each
  node. It also assumes that the children of each node are sorted in
  order of increasing low.  Returns the pointer to the root of the
  group upon successful termination; NULL otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
MtrNode *
Mtr_FindGroup( MtrNode * root /* root of the group tree */ ,
			   unsigned int low /* lower bound of the group */ ,
			   unsigned int size /* upper bound of the group */  )
{
	MtrNode *node;

#ifdef MTR_DEBUG
	/* We cannot have a non-empty proper subgroup of a singleton set. */
	assert( !MTR_TEST( root, MTR_TERMINAL ) );
#endif

	/* Sanity check. */
	if ( size < 1 )
		return ( NULL );

	/* Check whether current group includes the group sought.  This
	   ** check is necessary at the top-level call.  In the subsequent
	   ** calls it is redundant. */
	if ( low < ( unsigned int ) root->low ||
		 low + size > ( unsigned int ) ( root->low + root->size ) )
		return ( NULL );

	if ( root->size == size && root->low == low )
		return ( root );

	if ( root->child == NULL )
		return ( NULL );

	/* Find all chidren of root that are included in the new group. If
	   ** the group of any child entirely contains the new group, call
	   ** Mtr_MakeGroup recursively.  */
	node = root->child;
	while ( low >= ( unsigned int ) ( node->low + node->size ) )
	{
		node = node->younger;
	}
	if ( low + size <= ( unsigned int ) ( node->low + node->size ) )
	{
		/* The group is contained in the group of node. */
		node = Mtr_FindGroup( node, low, size );
		return ( node );
	}
	else
	{
		return ( NULL );
	}

}								/* end of Mtr_FindGroup */


/**Function********************************************************************

  Synopsis    [Swaps two children of a tree node.]

  Description [Swaps two children of a tree node. Adjusts the high and
  low fields of the two nodes and their descendants.  The two children
  must be adjacent. However, first may be the younger sibling of second.
  Returns 1 in case of success; 0 otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
int
Mtr_SwapGroups( MtrNode * first /* first node to be swapped */ ,
				MtrNode * second /* second node to be swapped */  )
{
	MtrNode *node;
	MtrNode *parent;
	int sizeFirst;
	int sizeSecond;

	if ( second->younger == first )
	{							/* make first first */
		node = first;
		first = second;
		second = node;
	}
	else if ( first->younger != second )
	{							/* non-adjacent */
		return ( 0 );
	}

	sizeFirst = first->size;
	sizeSecond = second->size;

	/* Swap the two nodes. */
	parent = first->parent;
	if ( parent == NULL || second->parent != parent )
		return ( 0 );
	if ( parent->child == first )
	{
		parent->child = second;
	}
	else
	{							/* first->elder != NULL */
		first->elder->younger = second;
	}
	if ( second->younger != NULL )
	{
		second->younger->elder = first;
	}
	first->younger = second->younger;
	second->elder = first->elder;
	first->elder = second;
	second->younger = first;

	/* Adjust the high and low fields. */
	if ( !mtrShiftHL( first, sizeSecond ) )
		return ( 0 );
	if ( !mtrShiftHL( second, -sizeFirst ) )
		return ( 0 );

	return ( 1 );

}								/* end of Mtr_SwapGroups */


/**Function********************************************************************

  Synopsis    [Prints the groups as a parenthesized list.]

  Description [Prints the groups as a parenthesized list. After each
  group, the group's flag are printed, preceded by a `|'.  For each
  flag (except MTR_TERMINAL) a character is printed.
  <ul>
  <li>F: MTR_FIXED
  <li>N: MTR_NEWNODE
  <li>S: MTR_SOFT
  </ul>
  The second argument, silent, if different from 0, causes
  Mtr_PrintGroups to only check the syntax of the group tree.
  ]

  SideEffects [None]

  SeeAlso     [Mtr_PrintTree]

******************************************************************************/
void
Mtr_PrintGroups( MtrNode * root /* root of the group tree */ ,
				 int silent /* flag to check tree syntax only */  )
{
	MtrNode *node;

	assert( root != NULL );
	assert( root->younger == NULL || root->younger->elder == root );
	assert( root->elder == NULL || root->elder->younger == root );
	if ( !silent )
		( void ) printf( "(%d", root->low );
	if ( MTR_TEST( root, MTR_TERMINAL ) || root->child == NULL )
	{
		if ( !silent )
			( void ) printf( "," );
	}
	else
	{
		node = root->child;
		while ( node != NULL )
		{
			assert( node->low >= root->low
					&& ( int ) ( node->low + node->size ) <=
					( int ) ( root->low + root->size ) );
			assert( node->parent == root );
			Mtr_PrintGroups( node, silent );
			node = node->younger;
		}
	}
	if ( !silent )
	{
		( void ) printf( "%d", root->low + root->size - 1 );
		if ( root->flags != MTR_DEFAULT )
		{
			( void ) printf( "|" );
			if ( MTR_TEST( root, MTR_FIXED ) )
				( void ) printf( "F" );
			if ( MTR_TEST( root, MTR_NEWNODE ) )
				( void ) printf( "N" );
			if ( MTR_TEST( root, MTR_SOFT ) )
				( void ) printf( "S" );
		}
		( void ) printf( ")" );
		if ( root->parent == NULL )
			( void ) printf( "\n" );
	}
	assert( ( root->
			  flags & ~( MTR_TERMINAL | MTR_SOFT | MTR_FIXED | MTR_NEWNODE ) )
			== 0 );
	return;

}								/* end of Mtr_PrintGroups */


/**Function********************************************************************

  Synopsis    [Reads groups from a file and creates a group tree.]

  Description [Reads groups from a file and creates a group tree.
  Each group is specified by three fields:
  <xmp>
       low size flags.
  </xmp>
  Low and size are (short) integers. Flags is a string composed of the
  following characters (with associated translation):
  <ul>
  <li>D: MTR_DEFAULT
  <li>F: MTR_FIXED
  <li>N: MTR_NEWNODE
  <li>S: MTR_SOFT
  <li>T: MTR_TERMINAL
  </ul>
  Normally, the only flags that are needed are D and F.  Groups and
  fields are separated by white space (spaces, tabs, and newlines).
  Returns a pointer to the group tree if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [Mtr_InitGroupTree Mtr_MakeGroup]

******************************************************************************/
MtrNode *
Mtr_ReadGroups( FILE * fp /* file pointer */ ,
				int nleaves /* number of leaves of the new tree */  )
{
	int low;
	int size;
	int err;
	unsigned int flags;
	MtrNode *root;
	MtrNode *node;
	char attrib[8 * sizeof( unsigned int ) + 1];
	char *c;

	root = Mtr_InitGroupTree( 0, nleaves );
	if ( root == NULL )
		return NULL;

	while ( !feof( fp ) )
	{
		/* Read a triple and check for consistency. */
		err = fscanf( fp, "%d %d %s", &low, &size, attrib );
		if ( err == EOF )
		{
			break;
		}
		else if ( err != 3 )
		{
			return ( NULL );
		}
		else if ( low < 0 || low + size > nleaves || size < 1 )
		{
			return ( NULL );
		}
		else if ( strlen( attrib ) > 8 * sizeof( MtrHalfWord ) )
		{
			/* Not enough bits in the flags word to store these many
			   ** attributes. */
			return ( NULL );
		}

		/* Parse the flag string. Currently all flags are permitted,
		   ** to make debugging easier. Normally, specifying NEWNODE
		   ** wouldn't be allowed. */
		flags = MTR_DEFAULT;
		for ( c = attrib; *c != 0; c++ )
		{
			switch ( *c )
			{
			case 'D':
				break;
			case 'F':
				flags |= MTR_FIXED;
				break;
			case 'N':
				flags |= MTR_NEWNODE;
				break;
			case 'S':
				flags |= MTR_SOFT;
				break;
			case 'T':
				flags |= MTR_TERMINAL;
				break;
			default:
				return NULL;
			}
		}
		node = Mtr_MakeGroup( root, ( MtrHalfWord ) low, ( MtrHalfWord ) size,
							  flags );
		if ( node == NULL )
			return ( NULL );
	}

	return ( root );

}								/* end of Mtr_ReadGroups */


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

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


/**Function********************************************************************

  Synopsis    [Adjusts the low fields of a node and its descendants.]

  Description [Adjusts the low fields of a node and its
  descendants. Adds shift to low of each node. Checks that no
  out-of-bounds values result.  Returns 1 in case of success; 0
  otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
static int
mtrShiftHL( MtrNode * node /* group tree node */ ,
			int shift /* amount by which low should be changed */  )
{
	MtrNode *auxnode;
	int low;

	low = ( int ) node->low;


	low += shift;

	if ( low < 0 || low + ( int ) ( node->size - 1 ) > ( int ) MTR_MAXHIGH )
		return ( 0 );

	node->low = ( MtrHalfWord ) low;

	if ( !MTR_TEST( node, MTR_TERMINAL ) && node->child != NULL )
	{
		auxnode = node->child;
		do
		{
			if ( !mtrShiftHL( auxnode, shift ) )
				return ( 0 );
			auxnode = auxnode->younger;
		}
		while ( auxnode != NULL );
	}

	return ( 1 );

}								/* end of mtrShiftHL */
