4.3BSD - /usr/src/ucb/pascal/pdx/tree/tr_equal.c

   1: /*
   2:  * Copyright (c) 1980 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifndef lint
   8: static char sccsid[] = "@(#)tr_equal.c	5.1 (Berkeley) 6/6/85";
   9: #endif not lint
  10: 
  11: /*
  12:  * A recursive tree search routine to test if two trees
  13:  * are structurally equivalent.
  14:  */
  15: 
  16: #include "defs.h"
  17: #include "tree.h"
  18: #include "tree.rep"
  19: 
  20: BOOLEAN tr_equal(t1, t2)
  21: register NODE *t1;
  22: register NODE *t2;
  23: {
  24:     if (t1 == NIL && t2 == NIL) {
  25:         return(TRUE);
  26:     }
  27:     if (t1 == NIL || t2 == NIL) {
  28:         return(FALSE);
  29:     }
  30:     if (t1->op != t2->op || degree(t1->op) != degree(t2->op)) {
  31:         return(FALSE);
  32:     }
  33:     switch(degree(t1->op)) {
  34:         case LEAF:
  35:             switch(t1->op) {
  36:                 case O_NAME:
  37:                     return(t1->nameval == t2->nameval);
  38: 
  39:                 case O_QNAME:
  40:                     if (!tr_equal(t1->right, t2->right)) {
  41:                         return(FALSE);
  42:                     }
  43:                     return(tr_equal(t1->left, t2->left));
  44: 
  45:                 case O_LCON:
  46:                     return(t1->lconval == t2->lconval);
  47: 
  48:                 case O_FCON:
  49:                     return(t1->fconval == t2->fconval);
  50: 
  51:                 case O_SCON:
  52:                     return(t1->sconval == t2->sconval);
  53: 
  54:                 default:
  55:                     panic("tr_equal: leaf %d\n", t1->op);
  56:             }
  57:             /*NOTREACHED*/
  58: 
  59:         case BINARY:
  60:             if (!tr_equal(t1->right, t2->right)) {
  61:                 return(FALSE);
  62:             }
  63:             /* else fall through */
  64:         case UNARY:
  65:             return(tr_equal(t1->left, t2->left));
  66: 
  67:         default:
  68:             panic("tr_equal: bad degree for op %d\n", t1->op);
  69:     }
  70:     /*NOTREACHED*/
  71: }

Defined functions

Defined variables