seq: fix testsuite failures

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

coreutils/seq.c

@@ -6,12 +6,10 @@
  *
  * Licensed under the GPL v2, see the file LICENSE in this tarball.
  */
-
 #include "libbb.h"
 
 /* This is a NOFORK applet. Be very careful! */
 
-
 int seq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int seq_main(int argc, char **argv)
 {
@@ -19,35 +17,72 @@ int seq_main(int argc, char **argv)
 		OPT_w = (1 << 0),
 		OPT_s = (1 << 1),
 	};
-	double last, increment, i;
+	double first, last, increment, v;
+	unsigned n;
+	unsigned width;
+	unsigned frac_part;
 	const char *sep, *opt_s = "\n";
 	unsigned opt = getopt32(argv, "+ws:", &opt_s);
-	unsigned width = 0;
 
 	argc -= optind;
 	argv += optind;
-	i = increment = 1;
+	first = increment = 1;
+	errno = 0;
 	switch (argc) {
+			char *pp;
 		case 3:
-			increment = atof(argv[1]);
+			increment = strtod(argv[1], &pp);
+			errno |= *pp;
 		case 2:
-			i = atof(*argv);
+			first = strtod(argv[0], &pp);
+			errno |= *pp;
 		case 1:
-			last = atof(argv[argc-1]);
-			break;
+			last = strtod(argv[argc-1], &pp);
+			if (!errno && *pp == '\0')
+				break;
 		default:
 			bb_show_usage();
 	}
-	if (opt & OPT_w) /* Pad to length of start or last */
-		width = MAX(strlen(*argv), strlen(argv[argc-1]));
 
-	/* You should note that this is pos-5.0.91 semantics, -- FK. */
-	sep = "";
-	while ((increment > 0 && i <= last) || (increment < 0 && i >= last)) {
-		printf("%s%0*g", sep, width, i);
-		sep = opt_s;
-		i += increment;
+	/* Last checked to be compatible with: coreutils-6.10 */
+	width = 0;
+	frac_part = 0;
+	while (1) {
+		char *dot = strchrnul(*argv, '.');
+		int w = (dot - *argv);
+		int f = strlen(dot);
+		if (width < w)
+			width = w;
+		argv++;
+		if (!*argv)
+			break;
+		/* Why do the above _before_ frac check below?
+		 * Try "seq 1 2.0" and "seq 1.0 2.0":
+		 * coreutils never pay attention to the number
+		 * of fractional digits in last arg. */
+		if (frac_part < f)
+			frac_part = f;
 	}
-	bb_putchar('\n');
+	if (frac_part) {
+		frac_part--;
+		if (frac_part)
+			width += frac_part + 1;
+	}
+	if (!(opt & OPT_w))
+		width = 0;
+
+	sep = "";
+	v = first;
+	n = 0;
+	while (increment >= 0 ? v <= last : v >= last) {
+		printf("%s%0*.*f", sep, width, frac_part, v);
+		sep = opt_s;
+		/* v += increment; - would accumulate floating point errors */
+		n++;
+		v = first + n * increment;
+	}
+	if (n) /* if while loop executed at least once */
+		bb_putchar('\n');
+
 	return fflush(stdout);
 }

docs/posix_conformance.txt

@@ -189,7 +189,7 @@ df POSIX options
 df Busybox specific options: 
   -a, -m, -B SIZE, -i, -h
 Remark:
-- It seems that GNU df doesnt rount percents up in its output (thus its results are a bit different)
+- It seems that GNU df does not round percents up in its output (thus its results are a bit different)
 
 diff POSIX options
  option           | exists | compliant | remarks

testsuite/runtest

@@ -120,11 +120,13 @@ fi
 
 # Populate a directory with links to all busybox applets
 
+# Note: if $LINKSDIR/applet exists, we do not overwrite it.
+# Useful if one wants to run tests against a standard utility, not an applet.
 LINKSDIR="$bindir/runtest-tempdir-links"
-rm -rf "$LINKSDIR" 2>/dev/null
-mkdir "$LINKSDIR"
+#rm -rf "$LINKSDIR" 2>/dev/null
+mkdir "$LINKSDIR" 2>/dev/null
 for i in $implemented; do
-	ln -s "$bindir/busybox" "$LINKSDIR/$i"
+	ln -s "$bindir/busybox" "$LINKSDIR/$i" 2>/dev/null
 done
 
 # Set up option flags so tests can be selective.
@@ -142,7 +144,7 @@ for applet in $applets; do
 
 	# Is this a new-style test?
 	if [ -f "$applet.tests" ]; then
-		if [ ! -h "$LINKSDIR/$applet" ]; then
+		if [ ! -e "$LINKSDIR/$applet" ]; then
 			# (avoiding bash'ism "${applet:0:4}")
 			if ! echo "$applet" | grep "^all_" >/dev/null; then
 				echo "SKIPPED: $applet (not built)"

testsuite/seq.tests

@@ -29,16 +29,18 @@ testing "seq count up by 2" "seq 4 2 8" "4\n6\n8\n" "" ""
 testing "seq count down by 2" "seq 8 -2 4" "8\n6\n4\n" "" ""
 testing "seq count wrong way #1" "seq 4 -2 8" "" "" ""
 testing "seq count wrong way #2" "seq 8 2 4" "" "" ""
-# Fails: first item is printed as 3, not 3.0
-# note: makes sense to fix "seq 3 .30 4" case as well
 testing "seq count by .3" "seq 3 .3 4" "3.0\n3.3\n3.6\n3.9\n" "" ""
-testing "seq count by -.9" "seq .7 -.9 -2.2" "0.7\n-0.2\n-1.1\n-2\n" "" ""
-testing "seq count by zero" "seq 4 0 8 | head -n 10" "" "" ""
+testing "seq count by .30" "seq 3 .30 4" "3.00\n3.30\n3.60\n3.90\n" "" ""
+testing "seq count by .30 to 4.000" "seq 3 .30 4.000" "3.00\n3.30\n3.60\n3.90\n" "" ""
+testing "seq count by -.9" "seq .7 -.9 -2.2" "0.7\n-0.2\n-1.1\n-2.0\n" "" ""
+testing "seq count by zero" "seq 4 0 8 | head -n 10" "4\n4\n4\n4\n4\n4\n4\n4\n4\n4\n" "" ""
 
 testing "seq one argument with padding" "seq -w 003" "001\n002\n003\n" "" ""
 testing "seq two arguments with padding" "seq -w 005 7" "005\n006\n007\n" "" ""
 testing "seq count down by 3 with padding" "seq -w 8 -3 04" "08\n05\n" "" ""
-# Known to fail
-testing "seq count by .3 with padding" "seq -w 03 .3 0004" "003.0\n003.3\n003.6\n003.9\n" "" ""
+# Looks like a bug in coreutils 6.10: it uses width one less than needed
+# These tests contain the expected "fixed" output
+testing "seq count by .3 with padding 1" "seq -w 09 .3 11" "09.0\n09.3\n09.6\n09.9\n10.2\n10.5\n10.8\n" "" ""
+testing "seq count by .3 with padding 2" "seq -w 03 .3 0004" "0003.0\n0003.3\n0003.6\n0003.9\n" "" ""
 
 exit $FAILCOUNT