stat: revert %X-%Y-%Z change; use e.g., %:X to print fractional seconds

This reverts part of the recent commit 9069af45,
"stat: print timestamps to full resolution", which made %X, %Y, %Z
print floating point numbers.  We prefer to retain portability of
%X, %Y and %Z uses, while still providing access to full-resolution
time stamps via modified format strings.  Also make the new
%W consistent.
* src/stat.c: Include "xstrtol.h".
(print_it): Accept a new %...:[XYZ] format directive,
e.g., %:X, to print the nanoseconds portion of the corresponding time.
For example, %3.3:Y prints the zero-padded, truncated, milliseconds
part of the time of last modification.
(print_it): Update print_func signature to match.
(neg_to_zero): New helper function.
(epoch_time): Remove function; replace with...
(epoch_sec): New function; use timetostr.
(out_ns): New function.  Use "09" only when no other modifier
is specified.
(print_statfs): Change type of "m" to unsigned int,
now that it must accommodate values larger than 255.
(print_stat): Likewise.
Map :X to a code of 'X' + 256.  Likewise for Y, Z and W.
(usage): Update.
* tests/touch/60-seconds: Use %Y.%:Y in place of %Y.
* tests/misc/stat-nanoseconds: New file.
* tests/Makefile.am (TESTS): Add it.
* NEWS (Changes in behavior): Mention this.
With improvements by Pádraig Brady.
Thanks to Andreas Schwab for raising the issue.

3 files changed, 38 insertions, 1 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 84db367b1..dd1c509b9 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -244,6 +244,7 @@ TESTS =						\
   misc/stat-fmt					\
   misc/stat-hyphen				\
   misc/stat-mount				\
+  misc/stat-nanoseconds				\
   misc/stat-printf				\
   misc/stat-slash				\
   misc/stdbuf					\
diff --git a/tests/misc/stat-nanoseconds b/tests/misc/stat-nanoseconds
new file mode 100755
index 000000000..314f43e2c
--- /dev/null
+++ b/tests/misc/stat-nanoseconds
@@ -0,0 +1,36 @@
+#!/bin/sh
+# Exercise format strings involving %:X, %:Y, etc.
+
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+test "$VERBOSE" = yes && stat --version
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+
+touch -d '2010-10-21 18:43:33.023456789' k || framework_failure_
+
+ls --full-time | grep 18:43:33.023456789 \
+  || skip_ this file system does not support sub-second time stamps
+
+test "$(stat -c      %:X k)" = 023456789  || fail=1
+test "$(stat -c     %3:X k)" = 23456789   || fail=1
+test "$(stat -c   %3.3:X k)" = 023        || fail=1
+test "$(stat -c    %.3:X k)" = 023        || fail=1
+test "$(stat -c  %03.3:X k)" = 023        || fail=1
+test "$(stat -c  %-5.3:X k)" = '023  '    || fail=1
+test "$(stat -c  %05.3:X k)" = '  023'    || fail=1
+test "$(stat -c %010.3:X k)" = '       023' || fail=1
+
+Exit $fail
diff --git a/tests/touch/60-seconds b/tests/touch/60-seconds
index f98f0c5d1..d0082967c 100755
--- a/tests/touch/60-seconds
+++ b/tests/touch/60-seconds
@@ -30,7 +30,7 @@ echo 60.000000000 > exp || framework_failure
 # an `invalid date format'.  Specifying 60 seconds *is* valid.
 TZ=UTC0 touch -t 197001010000.60 f || fail=1
 
-stat --p='%Y\n' f > out || fail=1
+stat --p='%Y.%:Y\n' f > out || fail=1
 
 compare out exp || fail=1