[PATCH] sleep: allow ms suffix for milliseconds

[Rasmus Villemoes]

* src/sleep.c: Accept ms suffix.
* doc/coreutils.texi (sleep invocation): Document it.

When one wants to sleep for some number of milliseconds, one can
do (at least in bash)

  sleep $(printf '%d.%03d' $((x/1000)) $((x%1000)))

but that's a bit cumbersome. Extend sleep(1) to also accept "ms" as a
suffix, so one can instead do

  sleep ${x}ms
---
 doc/coreutils.texi |  4 +++-
 src/sleep.c        | 59 ++++++++++++++++++++--------------------------
 2 files changed, 29 insertions(+), 34 deletions(-)

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 32ddba597..9b2ae431b 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -18225,7 +18225,7 @@ the values of the command line arguments.
 Synopsis:
 
 @example
-sleep @var{number}[smhd]@dots{}
+sleep @var{number}[ms|s|m|h|d]@dots{}
 @end example
 
 @cindex time units
@@ -18233,6 +18233,8 @@ Each argument is a non-negative number followed by an 
optional unit; the default
 is seconds.  The units are:
 
 @table @samp
+@item ms
+milliseconds
 @item s
 seconds
 @item m
diff --git a/src/sleep.c b/src/sleep.c
index 1c5f7c607..7ea0d6c84 100644
--- a/src/sleep.c
+++ b/src/sleep.c
@@ -45,9 +45,9 @@ usage (int status)
 Usage: %s NUMBER[SUFFIX]...\n\
   or:  %s OPTION\n\
 Pause for NUMBER seconds.  SUFFIX may be 's' for seconds (the default),\n\
-'m' for minutes, 'h' for hours or 'd' for days.  NUMBER need not be an\n\
-integer.  Given two or more arguments, pause for the amount of time\n\
-specified by the sum of their values.\n\
+'ms' for milliseconds, 'm' for minutes, 'h' for hours or 'd' for days.\n\
+NUMBER need not be an integer.  Given two or more arguments, pause for\n\
+the amount of time specified by the sum of their values.\n\
 \n\
 "),
               program_name, program_name);
@@ -58,35 +58,30 @@ specified by the sum of their values.\n\
   exit (status);
 }
 
-/* Given a floating point value *X, and a suffix character, SUFFIX_CHAR,
-   scale *X by the multiplier implied by SUFFIX_CHAR.  SUFFIX_CHAR may
-   be the NUL byte or 's' to denote seconds, 'm' for minutes, 'h' for
-   hours, or 'd' for days.  If SUFFIX_CHAR is invalid, don't modify *X
-   and return false.  Otherwise return true.  */
+/* Given a floating point value *X, and a suffix, SUFFIX, scale *X by
+   the multiplier implied by SUFFIX.  SUFFIX may be "ms" to denote
+   milliseconds, the empty string or "s" for seconds, "m" for minutes,
+   "h" for hours, or "d" for days.  If SUFFIX is invalid, don't modify
+   *X and return false.  Otherwise return true.  */
 
 static bool
-apply_suffix (double *x, char suffix_char)
+apply_suffix (double *x, const char *suffix)
 {
-  int multiplier;
-
-  switch (suffix_char)
-    {
-    case 0:
-    case 's':
-      multiplier = 1;
-      break;
-    case 'm':
-      multiplier = 60;
-      break;
-    case 'h':
-      multiplier = 60 * 60;
-      break;
-    case 'd':
-      multiplier = 60 * 60 * 24;
-      break;
-    default:
-      return false;
-    }
+  double multiplier;
+
+  if (STREQ (suffix, "") || STREQ (suffix, "s"))
+    return true;
+
+  if (STREQ (suffix, "ms"))
+    multiplier = 0.001;
+  else if (STREQ (suffix, "m"))
+    multiplier = 60;
+  else if (STREQ (suffix, "h"))
+    multiplier = 60 * 60;
+  else if (STREQ (suffix, "d"))
+    multiplier = 60 * 60 * 24;
+  else
+    return false;
 
   *x *= multiplier;
 
@@ -124,10 +119,8 @@ main (int argc, char **argv)
       if (! (xstrtod (argv[i], &p, &s, cl_strtod) || errno == ERANGE)
           /* Nonnegative interval.  */
           || ! (0 <= s)
-          /* No extra chars after the number and an optional s,m,h,d char.  */
-          || (*p && *(p+1))
-          /* Check any suffix char and update S based on the suffix.  */
-          || ! apply_suffix (&s, *p))
+          /* Check any suffix and update S based on the suffix.  */
+          || ! apply_suffix (&s, p))
         {
           error (0, 0, _("invalid time interval %s"), quote (argv[i]));
           ok = false;
-- 
2.23.0