/********************************************
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 1.1.1.1  1993/03/21 09:45:37  cgd
/*initial import of 386bsd-0.1 sources
/*
 * Revision 3.4  92/02/20  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) ;
  (void)  memcpy( mp->start + sz1, np->start, SIZE_T(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 ) ;
  (void) memcpy( p+1, mp->start, SIZE_T(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 ;
  (void) memcpy( p + szm + 1 , np->start, SIZE_T(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 ) ;
  (void) memcpy( p+1, mp->start, SIZE_T(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 ) ;
  (void) memcpy( p+1, mp->start, SIZE_T(sz * STATESZ)) ;
  free( mp->start ) ;
  mp->start = p ;
  mp->stop = p + sz ;
  p->type = M_2JB ;
  p->data.jump = sz ;
}

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


VOID *RE_malloc( sz ) 
  unsigned sz ;
{ register VOID *p ;

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

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