[src/trunk]: src/usr.bin/make make(1): restructure code of the :ts modifier

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

details:   https://anonhg.NetBSD.org/src/rev/5f521d485066
branches:  trunk
changeset: 943028:5f521d485066
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Aug 23 22:13:38 2020 +0000

description:
make(1): restructure code of the :ts modifier

Now there is one paragraph per case, as opposed to the highly condensed
code from before.

In the cases of :ts\n and :ts\t, the variables for number parsing are no
longer in the code path, which makes the code easier to understand for
humans.  Not sure what the compilers made out of it.

The assignment "base = 0" has gone since it was redundant.  An integer
that starts with 0 is always interpreted as octal by strtol, no matter
if the base is 8 or 0.

diffstat:

 usr.bin/make/var.c |  86 ++++++++++++++++++++++++++++-------------------------
 1 files changed, 46 insertions(+), 40 deletions(-)

diffs (122 lines):

diff -r 245b0da2855f -r 5f521d485066 usr.bin/make/var.c
--- a/usr.bin/make/var.c        Sun Aug 23 21:40:30 2020 +0000
+++ b/usr.bin/make/var.c        Sun Aug 23 22:13:38 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: var.c,v 1.467 2020/08/23 21:40:30 rillig Exp $ */
+/*     $NetBSD: var.c,v 1.468 2020/08/23 22:13:38 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -69,14 +69,14 @@
  */
 
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: var.c,v 1.467 2020/08/23 21:40:30 rillig Exp $";
+static char rcsid[] = "$NetBSD: var.c,v 1.468 2020/08/23 22:13:38 rillig Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)var.c      8.3 (Berkeley) 3/19/94";
 #else
-__RCSID("$NetBSD: var.c,v 1.467 2020/08/23 21:40:30 rillig Exp $");
+__RCSID("$NetBSD: var.c,v 1.468 2020/08/23 22:13:38 rillig Exp $");
 #endif
 #endif /* not lint */
 #endif
@@ -2498,52 +2498,58 @@
     /* XXX: pp points to the 's', for historic reasons only.
      * Changing this will influence the error messages. */
     const char *sep = *pp + 1;
+
+    /* ":ts<any><endc>" or ":ts<any>:" */
     if (sep[0] != st->endc && (sep[1] == st->endc || sep[1] == ':')) {
-       /* ":ts<any><endc>" or ":ts<any>:" */
        st->sep = sep[0];
        *pp = sep + 1;
-    } else if (sep[0] == st->endc || sep[0] == ':') {
-       /* ":ts<endc>" or ":ts:" */
+       goto ok;
+    }
+
+    /* ":ts<endc>" or ":ts:" */
+    if (sep[0] == st->endc || sep[0] == ':') {
        st->sep = '\0';         /* no separator */
        *pp = sep;
-    } else if (sep[0] == '\\') {
-       const char *xp = sep + 1;
+       goto ok;
+    }
+
+    /* ":ts<unrecognised><unrecognised>". */
+    if (sep[0] != '\\')
+       return AMR_BAD;
+
+    /* ":ts\n" */
+    if (sep[1] == 'n') {
+       st->sep = '\n';
+       *pp = sep + 2;
+       goto ok;
+    }
+
+    /* ":ts\t" */
+    if (sep[1] == 't') {
+       st->sep = '\t';
+       *pp = sep + 2;
+       goto ok;
+    }
+
+    /* ":ts\x40" or ":ts\100" */
+    {
+       const char *numStart = sep + 1;
        int base = 8;           /* assume octal */
-
-       switch (sep[1]) {
-       case 'n':
-           st->sep = '\n';
-           *pp = sep + 2;
-           break;
-       case 't':
-           st->sep = '\t';
-           *pp = sep + 2;
-           break;
-       case 'x':
+       char *end;
+
+       if (sep[1] == 'x') {
            base = 16;
-           xp++;
-           goto get_numeric;
-       case '0':
-           base = 0;
-           goto get_numeric;
-       default:
-           if (!isdigit((unsigned char)sep[1]))
-               return AMR_BAD; /* ":ts<backslash><unrecognised>". */
-
-       get_numeric:
-           {
-               char *end;
-               st->sep = (char)strtoul(xp, &end, base);
-               if (*end != ':' && *end != st->endc)
-                   return AMR_BAD;
-               *pp = end;
-           }
-           break;
-       }
-    } else {
-       return AMR_BAD;         /* Found ":ts<unrecognised><unrecognised>". */
+           numStart++;
+       } else if (!isdigit((unsigned char)sep[1]))
+           return AMR_BAD;     /* ":ts<backslash><unrecognised>". */
+
+       st->sep = (char)strtoul(numStart, &end, base);
+       if (*end != ':' && *end != st->endc)
+           return AMR_BAD;
+       *pp = end;
     }
 
+ok:
     st->newVal = ModifyWords(st->ctxt, st->sep, st->oneBigWord, st->val,
                             ModifyWord_Copy, NULL);
     return AMR_OK;