seq: fix testsuite failures

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

1 files changed, 51 insertions, 16 deletions

diff --git a/coreutils/seq.c b/coreutils/seq.c
index 4b853c6..bb39a5b 100644
--- a/coreutils/seq.c
+++ b/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. */
+	/* 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;
+	}
+	if (frac_part) {
+		frac_part--;
+		if (frac_part)
+			width += frac_part + 1;
+	}
+	if (!(opt & OPT_w))
+		width = 0;
+
 	sep = "";
-	while ((increment > 0 && i <= last) || (increment < 0 && i >= last)) {
-		printf("%s%0*g", sep, width, i);
+	v = first;
+	n = 0;
+	while (increment >= 0 ? v <= last : v >= last) {
+		printf("%s%0*.*f", sep, width, frac_part, v);
 		sep = opt_s;
-		i += increment;
+		/* v += increment; - would accumulate floating point errors */
+		n++;
+		v = first + n * increment;
 	}
-	bb_putchar('\n');
+	if (n) /* if while loop executed at least once */
+		bb_putchar('\n');
+
 	return fflush(stdout);
 }