Re: POINTERRIGOR

On Mon, 18 Jun 2001, Abhijit Menon-Sen wrote:

> util.c does:
> 
>     #ifdef POINTERRIGOR

[ . . . ]

> What's this for? (POINTERRIGOR is not defined anywhere, and the p5p
> archive doesn't know.) Do some compilers which have problems comparing
> things like "s += tmp"?  Which ones?

Short answer:  It's very old and can probably be safely removed.

Longer answer:

It was added in perl3.027, but I didn't see any obvious
description for it.  It may well have been addressing a concern
that a statement like C<big -= previous;>  could end up with C<big>
crossing a segment boundary in a segmented architecture.

However, nothing's been setting POINTERRIGOR in perl5 for years, so I
think it can be safely dropped.  That way it won't get picked up and 
carried over to perl6 :-).

Here's a patch to do so.

diff -r -u perl-current/util.c perl-andy/util.c
--- perl-current/util.c	Mon Jul  2 05:06:08 2001
+++ perl-andy/util.c	Tue Jul  3 10:58:45 2001
@@ -692,16 +692,8 @@
 	  top2:
 	    /*SUPPRESS 560*/
 	    if ((tmp = table[*s])) {
-#ifdef POINTERRIGOR
-		if (bigend - s > tmp) {
-		    s += tmp;
-		    goto top2;
-		}
-		s += tmp;
-#else
 		if ((s += tmp) < bigend)
 		    goto top2;
-#endif
 		goto check_end;
 	    }
 	    else {		/* less expensive than calling strncmp() */
@@ -795,25 +787,6 @@
 	if (!(pos += PL_screamnext[pos]))
 	    goto cant_find;
     }
-#ifdef POINTERRIGOR
-    do {
-	if (pos >= stop_pos) break;
-	if (big[pos-previous] != first)
-	    continue;
-	for (x=big+pos+1-previous,s=little; s < littleend; /**/ ) {
-	    if (*s++ != *x++) {
-		s--;
-		break;
-	    }
-	}
-	if (s == littleend) {
-	    *old_posp = pos;
-	    if (!last) return (char *)(big+pos-previous);
-	    found = 1;
-	}
-    } while ( pos += PL_screamnext[pos] );
-    return (last && found) ? (char *)(big+(*old_posp)-previous) : Nullch;
-#else /* !POINTERRIGOR */
     big -= previous;
     do {
 	if (pos >= stop_pos) break;
@@ -833,7 +806,6 @@
     } while ( pos += PL_screamnext[pos] );
     if (last && found)
 	return (char *)(big+(*old_posp));
-#endif /* POINTERRIGOR */
   check_tail:
     if (!SvTAIL(littlestr) || (end_shift > 0))
 	return Nullch;

-- 
    Andy Dougherty		doughera@lafayette.edu
    Dept. of Physics
    Lafayette College, Easton PA 18042

• POINTERRIGOR by Abhijit Menon-Sen
• Re: POINTERRIGOR by Andy Dougherty
• Re: POINTERRIGOR by Jarkko Hietaniemi