File: rexp1.c

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/********************************************
rexp1.c
copyright 1991, Michael D. Brennan

This is a source file for mawk, an implementation of
the AWK programming language.

Mawk is distributed without warranty under the terms of
the GNU General Public License, version 2, 1991.
********************************************/

/*$Log: rexp1.c,v $
 * Revision 1.3  1993/07/24  17:55:10  mike
 * more cleanup
 *
 * Revision 1.2	 1993/07/23  13:21:41  mike
 * cleanup rexp code
 *
 * Revision 1.1.1.1  1993/07/03	 18:58:27  mike
 * move source to cvs
 *
 * Revision 3.4	 1992/02/20  16:08:12  brennan
 * change new_TWO() to work around sun acc bug
 *
 * Revision 3.3	 91/10/29  10:54:01  brennan
 * SIZE_T
 *
 * Revision 3.2	 91/08/13  09:10:11  brennan
 * VERSION .9994
 *
 * Revision 3.1	 91/06/07  10:33:22  brennan
 * VERSION 0.995
 *
*/

/*  re machine	operations  */

#include  "rexp.h"

static void PROTO(new_TWO, (int, MACHINE *)) ;



/* initialize a two state machine */
static void
new_TWO(type, mp)
   int type ;
   MACHINE *mp ;		 /* init mp-> */
{
   mp->start = (STATE *) RE_malloc(2 * STATESZ) ;
   mp->stop = mp->start + 1 ;
   mp->start->type = type ;
   mp->stop->type = M_ACCEPT ;
}

/*  build a machine that recognizes any	 */
MACHINE
RE_any()
{
   MACHINE x ;

   new_TWO(M_ANY, &x) ;
   return x ;
}

/*  build a machine that recognizes the start of string	 */
MACHINE
RE_start()
{
   MACHINE x ;

   new_TWO(M_START, &x) ;
   return x ;
}

MACHINE
RE_end()
{
   MACHINE x ;

   new_TWO(M_END, &x) ;
   return x ;
}

/*  build a machine that recognizes a class  */
MACHINE
RE_class(bvp)
   BV *bvp ;
{
   MACHINE x ;

   new_TWO(M_CLASS, &x) ;
   x.start->data.bvp = bvp ;
   return x ;
}

MACHINE
RE_u()
{
   MACHINE x ;

   new_TWO(M_U, &x) ;
   return x ;
}

MACHINE
RE_str(str, len)
   char *str ;
   unsigned len ;
{
   MACHINE x ;

   new_TWO(M_STR, &x) ;
   x.start->len = len ;
   x.start->data.str = str ;
   return x ;
}


/*  replace m and n by a machine that recognizes  mn   */
void
RE_cat(mp, np)
   MACHINE *mp, *np ;
{
   unsigned sz1, sz2, sz ;

   sz1 = mp->stop - mp->start ;
   sz2 = np->stop - np->start + 1 ;
   sz = sz1 + sz2 ;

   mp->start = (STATE *) RE_realloc(mp->start, sz * STATESZ) ;
   mp->stop = mp->start + (sz - 1) ;
   memcpy(mp->start + sz1, np->start, sz2 * STATESZ) ;
   free(np->start) ;
}

 /*  replace m by a machine that recognizes m|n	 */

void
RE_or(mp, np)
   MACHINE *mp, *np ;
{
   register STATE *p ;
   unsigned szm, szn ;

   szm = mp->stop - mp->start + 1 ;
   szn = np->stop - np->start + 1 ;

   p = (STATE *) RE_malloc((szm + szn + 1) * STATESZ) ;
   memcpy(p + 1, mp->start, szm * STATESZ) ;
   free(mp->start) ;
   mp->start = p ;
   (mp->stop = p + szm + szn)->type = M_ACCEPT ;
   p->type = M_2JA ;
   p->data.jump = szm + 1 ;
   memcpy(p + szm + 1, np->start, szn * STATESZ) ;
   free(np->start) ;
   (p += szm)->type = M_1J ;
   p->data.jump = szn ;
}

/*  UNARY  OPERATIONS	  */

/*  replace m by m*   */

void
RE_close(mp)
   MACHINE *mp ;
{
   register STATE *p ;
   unsigned sz ;

   sz = mp->stop - mp->start + 1 ;
   p = (STATE *) RE_malloc((sz + 2) * STATESZ) ;
   memcpy(p + 1, mp->start, sz * STATESZ) ;
   free(mp->start) ;
   mp->start = p ;
   mp->stop = p + (sz + 1) ;
   p->type = M_2JA ;
   p->data.jump = sz + 1 ;
   (p += sz)->type = M_2JB ;
   p->data.jump = -(sz - 1) ;
   (p + 1)->type = M_ACCEPT ;
}

/*  replace m  by  m+  (positive closure)   */

void
RE_poscl(mp)
   MACHINE *mp ;
{
   register STATE *p ;
   unsigned sz ;

   sz = mp->stop - mp->start + 1 ;
   mp->start = p = (STATE *) RE_realloc(mp->start, (sz + 1) * STATESZ) ;
   mp->stop = p + sz ;
   p += --sz ;
   p->type = M_2JB ;
   p->data.jump = -sz ;
   (p + 1)->type = M_ACCEPT ;
}

/* replace  m  by  m? (zero or one)  */

void
RE_01(mp)
   MACHINE *mp ;
{
   unsigned sz ;
   register STATE *p ;

   sz = mp->stop - mp->start + 1 ;
   p = (STATE *) RE_malloc((sz + 1) * STATESZ) ;
   memcpy(p + 1, mp->start, sz * STATESZ) ;
   free(mp->start) ;
   mp->start = p ;
   mp->stop = p + sz ;
   p->type = M_2JB ;
   p->data.jump = sz ;
}

/*===================================
MEMORY	ALLOCATION
 *==============================*/


PTR
RE_malloc(sz)
   unsigned sz ;
{
   register PTR p ;

   if (!(p = malloc(sz)))  RE_error_trap(MEMORY_FAILURE) ;
   return p ;
}

PTR
RE_realloc(p, sz)
   register PTR p ;
   unsigned sz ;
{
   if (!(p = realloc(p, sz)))  RE_error_trap(MEMORY_FAILURE) ;
   return p ;
}