[src/trunk]: src/usr.bin/make make(1): remove strange off-by-one feature in S...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3646685c9531
branches:  trunk
changeset: 1015345:3646685c9531
user:      rillig <rillig%NetBSD.org@localhost>
date:      Tue Oct 20 23:04:35 2020 +0000

description:
make(1): remove strange off-by-one feature in SuffSuffGetSuffix

The code worked as intended, yet it was strange to modify cp[1] to
temporarily shorten a string.  Using cp[0] for this purpose is common
style.

diffstat:

 usr.bin/make/suff.c |  16 +++++++---------
 1 files changed, 7 insertions(+), 9 deletions(-)

diffs (58 lines):

diff -r a445f7dfc59e -r 3646685c9531 usr.bin/make/suff.c
--- a/usr.bin/make/suff.c       Tue Oct 20 23:03:30 2020 +0000
+++ b/usr.bin/make/suff.c       Tue Oct 20 23:04:35 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: suff.c,v 1.198 2020/10/20 21:15:47 rillig Exp $        */
+/*     $NetBSD: suff.c,v 1.199 2020/10/20 23:04:35 rillig Exp $        */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -129,7 +129,7 @@
 #include "dir.h"
 
 /*     "@(#)suff.c     8.4 (Berkeley) 3/21/94" */
-MAKE_RCSID("$NetBSD: suff.c,v 1.198 2020/10/20 21:15:47 rillig Exp $");
+MAKE_RCSID("$NetBSD: suff.c,v 1.199 2020/10/20 23:04:35 rillig Exp $");
 
 #define SUFF_DEBUG0(text) DEBUG0(SUFF, text)
 #define SUFF_DEBUG1(fmt, arg1) DEBUG1(SUFF, fmt, arg1)
@@ -238,16 +238,14 @@
     char *name_end;
 };
 
-/* See if suff is a suffix of str. str->ename should point to THE END
- * of the string to check. (THE END == the null byte)
+/* See if suff is a suffix of str.
  *
  * Input:
  *     s               possible suffix
  *     str             string to examine
  *
  * Results:
- *     NULL if it ain't, pointer to character in str before suffix if
- *     it is.
+ *     NULL if it ain't, pointer to the start of suffix in str if it is.
  */
 static char *
 SuffSuffGetSuffix(const Suff *s, const struct SuffSuffGetSuffixArgs *str)
@@ -266,7 +264,7 @@
        p2--;
     }
 
-    return p1 == s->name - 1 ? p2 : NULL;
+    return p1 == s->name - 1 ? p2 + 1 : NULL;
 }
 
 /* Predicate form of SuffSuffGetSuffix, for Lst_Find. */
@@ -638,9 +636,9 @@
 
        /* Null-terminate the source suffix in order to find it. */
        /* XXX: don't modify strings, not even temporarily */
-       cp[1] = '\0';
+       cp[0] = '\0';
        s2 = FindSuffByName(transform->name);
-       cp[1] = s->name[0];             /* restore */
+       cp[0] = s->name[0];             /* restore */
 
        if (s2 != NULL) {
            /* establish the proper relationship */