[src/trunk]: src/usr.bin/make make(1): clean up TryParseNumber in conditions

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

details:   https://anonhg.NetBSD.org/src/rev/18621aeabc54
branches:  trunk
changeset: 956873:18621aeabc54
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Nov 08 22:22:03 2020 +0000

description:
make(1): clean up TryParseNumber in conditions

More descriptive variable names, more appropriate literals for
comparisons, one task per paragraph of code.

diffstat:

 usr.bin/make/cond.c |  43 ++++++++++++++++++++++---------------------
 1 files changed, 22 insertions(+), 21 deletions(-)

diffs (79 lines):

diff -r dff84bf168b9 -r 18621aeabc54 usr.bin/make/cond.c
--- a/usr.bin/make/cond.c       Sun Nov 08 21:56:47 2020 +0000
+++ b/usr.bin/make/cond.c       Sun Nov 08 22:22:03 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cond.c,v 1.188 2020/11/08 21:10:18 rillig Exp $        */
+/*     $NetBSD: cond.c,v 1.189 2020/11/08 22:22:03 rillig Exp $        */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -93,7 +93,7 @@
 #include "dir.h"
 
 /*     "@(#)cond.c     8.2 (Berkeley) 1/2/94"  */
-MAKE_RCSID("$NetBSD: cond.c,v 1.188 2020/11/08 21:10:18 rillig Exp $");
+MAKE_RCSID("$NetBSD: cond.c,v 1.189 2020/11/08 22:22:03 rillig Exp $");
 
 /*
  * The parsing of conditional expressions is based on this grammar:
@@ -336,40 +336,41 @@
     return gn != NULL && GNode_IsTarget(gn) && !Lst_IsEmpty(gn->commands);
 }
 
-/*-
+/*
  * Convert the given number into a double.
  * We try a base 10 or 16 integer conversion first, if that fails
  * then we try a floating point conversion instead.
  *
  * Results:
- *     Sets 'value' to double value of string.
  *     Returns TRUE if the conversion succeeded.
+ *     Sets 'out_value' to the converted number.
  */
 static Boolean
-TryParseNumber(const char *str, double *value)
+TryParseNumber(const char *str, double *out_value)
 {
-    char *eptr, ech;
-    unsigned long l_val;
-    double d_val;
+    char *end;
+    unsigned long ul_val;
+    double dbl_val;
 
     errno = 0;
-    if (!*str) {
-       *value = 0.0;
+    if (str[0] == '\0') {      /* XXX: why is an empty string a number? */
+       *out_value = 0.0;
        return TRUE;
     }
-    l_val = strtoul(str, &eptr, str[1] == 'x' ? 16 : 10);
-    ech = *eptr;
-    if (ech == '\0' && errno != ERANGE) {
-       d_val = str[0] == '-' ? -(double)-l_val : (double)l_val;
-    } else {
-       if (ech != '\0' && ech != '.' && ech != 'e' && ech != 'E')
-           return FALSE;
-       d_val = strtod(str, &eptr);
-       if (*eptr)
-           return FALSE;
+
+    ul_val = strtoul(str, &end, str[1] == 'x' ? 16 : 10);
+    if (*end == '\0' && errno != ERANGE) {
+       *out_value = str[0] == '-' ? -(double)-ul_val : (double)ul_val;
+       return TRUE;
     }
 
-    *value = d_val;
+    if (*end != '\0' && *end != '.' && *end != 'e' && *end != 'E')
+       return FALSE;           /* skip the expensive strtod call */
+    dbl_val = strtod(str, &end);
+    if (*end != '\0')
+       return FALSE;
+
+    *out_value = dbl_val;
     return TRUE;
 }