[irc/evilnet/x3.git] / rx / rxsimp.c

/*	Copyright (C) 1995, 1996 Tom Lord
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public License
 * along with this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330, 
 * Boston, MA 02111-1307, USA. 
 */

\f

#include "rxall.h"
#include "rxsimp.h"

\f


/* Could reasonably hashcons instead of in rxunfa.c */

#ifdef __STDC__
int
rx_simple_rexp (struct rexp_node ** answer,
		int cset_size,
		struct rexp_node *node,
		struct rexp_node ** subexps)
#else
int
rx_simple_rexp (answer, cset_size, node, subexps)
     struct rexp_node ** answer;
     int cset_size;
     struct rexp_node *node;
     struct rexp_node ** subexps;
#endif
{
  int stat;

  if (!node)
    {
      *answer = 0;
      return 0;
    }

  if (!node->observed)
    {
      rx_save_rexp (node);
      *answer = node;
      return 0;
    }

  if (node->simplified)
    {
      rx_save_rexp (node->simplified);
      *answer = node->simplified;
      return 0;
    }

  switch (node->type)
    {
    default:
    case r_cset:
    case r_string:
    case r_cut:
      return -2;		/* an internal error, really */

    case r_parens:
      stat = rx_simple_rexp (answer, cset_size,
			     node->params.pair.left,
			     subexps);
      break;

    case r_context:
      if (isdigit (node->params.intval))
	 stat = rx_simple_rexp (answer, cset_size,
				subexps [node->params.intval - '0'],
				subexps);
      else
	{
	  *answer = 0;
	  stat = 0;
	}
      break;

    case r_concat:
    case r_alternate:
    case r_opt:
    case r_star:
    case r_plus:
    case r_interval:
      {
	struct rexp_node *n;
	n = rexp_node (node->type);
	if (!n)
	  return -1;

	if (node->params.cset)
	  {
	    n->params.cset = rx_copy_cset (cset_size,
					   node->params.cset);
	    if (!n->params.cset)
	      {
		rx_free_rexp (n);
		return -1;
	      }
	  }
	n->params.intval = node->params.intval;
	n->params.intval2 = node->params.intval2;
	{
	  int s;
    
	  s = rx_simple_rexp (&n->params.pair.left, cset_size,
			      node->params.pair.left, subexps);
	  if (!s)
	    s = rx_simple_rexp (&n->params.pair.right, cset_size,
				node->params.pair.right, subexps);
	  if (!s)
	    {
	      *answer = n;
	      stat = 0;
	    }
	  else
	    {
	      rx_free_rexp  (n);
	      stat = s;
	    }
	}
      }      
      break;
    }

  if (!stat)
    {
      node->simplified = *answer;
      rx_save_rexp (node->simplified);
    }
  return stat;
}
Commit	Line	Data
d76ed9a9	1	/* Copyright (C) 1995, 1996 Tom Lord
	2	*
	3	* This program is free software; you can redistribute it and/or modify
	4	* it under the terms of the GNU Library General Public License as published by
	5	* the Free Software Foundation; either version 2, or (at your option)
	6	* any later version.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU Library General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU Library General Public License
	14	* along with this software; see the file COPYING. If not, write to
	15	* the Free Software Foundation, 59 Temple Place - Suite 330,
	16	* Boston, MA 02111-1307, USA.
	17	*/
	18
	19	\f
	20
	21	#include "rxall.h"
	22	#include "rxsimp.h"
	23
	24	\f
	25
	26
	27	/* Could reasonably hashcons instead of in rxunfa.c */
	28
	29	#ifdef __STDC__
	30	int
	31	rx_simple_rexp (struct rexp_node ** answer,
	32	int cset_size,
	33	struct rexp_node *node,
	34	struct rexp_node ** subexps)
	35	#else
	36	int
	37	rx_simple_rexp (answer, cset_size, node, subexps)
	38	struct rexp_node ** answer;
	39	int cset_size;
	40	struct rexp_node *node;
	41	struct rexp_node ** subexps;
	42	#endif
	43	{
	44	int stat;
	45
	46	if (!node)
	47	{
	48	*answer = 0;
	49	return 0;
	50	}
	51
	52	if (!node->observed)
	53	{
	54	rx_save_rexp (node);
	55	*answer = node;
	56	return 0;
	57	}
	58
	59	if (node->simplified)
	60	{
	61	rx_save_rexp (node->simplified);
	62	*answer = node->simplified;
	63	return 0;
	64	}
65
66	switch (node->type)
67	{
68	default:
69	case r_cset:
70	case r_string:
71	case r_cut:
72	return -2; /* an internal error, really */
73
74	case r_parens:
75	stat = rx_simple_rexp (answer, cset_size,
76	node->params.pair.left,
77	subexps);
78	break;
79
80	case r_context:
81	if (isdigit (node->params.intval))
82	stat = rx_simple_rexp (answer, cset_size,
83	subexps [node->params.intval - '0'],
84	subexps);
85	else
86	{
87	*answer = 0;
88	stat = 0;
89	}
90	break;
91
92	case r_concat:
93	case r_alternate:
94	case r_opt:
95	case r_star:
96	case r_plus:
97	case r_interval:
98	{
99	struct rexp_node *n;
100	n = rexp_node (node->type);
101	if (!n)
102	return -1;
103
104	if (node->params.cset)
105	{
106	n->params.cset = rx_copy_cset (cset_size,
107	node->params.cset);
108	if (!n->params.cset)
109	{
110	rx_free_rexp (n);
111	return -1;
112	}
113	}
114	n->params.intval = node->params.intval;
115	n->params.intval2 = node->params.intval2;
116	{
117	int s;
118
119	s = rx_simple_rexp (&n->params.pair.left, cset_size,
120	node->params.pair.left, subexps);
121	if (!s)
122	s = rx_simple_rexp (&n->params.pair.right, cset_size,
123	node->params.pair.right, subexps);
124	if (!s)
125	{
126	*answer = n;
127	stat = 0;
128	}
129	else
130	{
131	rx_free_rexp (n);
132	stat = s;
133	}
134	}
135	}
136	break;
137	}
138
139	if (!stat)
140	{
141	node->simplified = *answer;
142	rx_save_rexp (node->simplified);
143	}
144	return stat;
145	}
146
147