seq: ensure correct output width for scientific notation input

* src/seq.c (scan_arg): Calculate the width more accurately
for numbers specified using scientific notation.
* tests/misc/seq.pl: Add tests for cases that were mishandled.
* NEWS: Mention the fix.
* THANKS.in: Reported by Marcel Böhme.
Fixes http://bugs.gnu.org/12959

1 files changed, 15 insertions, 0 deletions

diff --git a/src/seq.c b/src/seq.c
index e5788caab..9c2c51fbe 100644
--- a/src/seq.c
+++ b/src/seq.c
@@ -166,6 +166,21 @@ scan_arg (const char *arg)
         {
           long exponent = strtol (e + 1, NULL, 10);
           ret.precision += exponent < 0 ? -exponent : 0;
+          /* Don't account for e.... in the width since this is not output.  */
+          ret.width -= strlen (arg) - (e - arg);
+          /* Adjust the width as per the exponent.  */
+          if (exponent < 0)
+            {
+              if (decimal_point)
+                {
+                  if (e == decimal_point + 1) /* undo #. -> # above  */
+                    ret.width++;
+                }
+              else
+                ret.width++;
+              exponent = -exponent;
+            }
+          ret.width += exponent;
         }
     }