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 4b853c698..bb39a5b54 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);
 }