date: introduce FEATURE_DATE_COMPAT; shrink

function                                             old     new   delta
date_main                                            889     862     -27

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

2 files changed, 41 insertions, 34 deletions

diff --git a/coreutils/Config.in b/coreutils/Config.in
index 1e32e2664..fe481ffe1 100644
--- a/coreutils/Config.in
+++ b/coreutils/Config.in
@@ -115,6 +115,22 @@ config FEATURE_DATE_ISOFMT
           Enable option (-I) to output an ISO-8601 compliant
           date/time string.
 
+config FEATURE_DATE_COMPAT
+        bool "Support weird 'date MMDDhhmm[[YY]YY][.ss]' format"
+        default y
+        depends on DATE
+        help
+          System time can be set by 'date -s DATE' and simply 'date DATE',
+          but formats of DATE string are different. 'date DATE' accepts
+          a rather weird MMDDhhmm[[YY]YY][.ss] format with completely
+          unnatural placement of year between minutes and seconds.
+          date -s (and other commands like touch -d) use more sensible
+          formats (for one, ISO format YYYY-MM-DD hh:mm:ss.ssssss).
+
+          With this option off, 'date DATE' is 'date -s DATE' support
+          the same format. With it on, 'date DATE' additionally supports
+          MMDDhhmm[[YY]YY][.ss] format.
+
 config DD
         bool "dd"
         default n
diff --git a/coreutils/date.c b/coreutils/date.c
index 11b63eaeb..4e5b3b0b8 100644
--- a/coreutils/date.c
+++ b/coreutils/date.c
@@ -71,12 +71,12 @@ static void maybe_set_utc(int opt)
 
 #if ENABLE_LONG_OPTS
 static const char date_longopts[] ALIGN1 =
-                "rfc-822\0" No_argument "R"
-                "rfc-2822\0" No_argument "R"
-                "set\0" Required_argument "s"
-                "utc\0" No_argument "u"
-                /*"universal\0" No_argument "u"*/
-                "date\0" Required_argument "d"
+                "rfc-822\0"   No_argument       "R"
+                "rfc-2822\0"  No_argument       "R"
+                "set\0"       Required_argument "s"
+                "utc\0"       No_argument       "u"
+        /*      "universal\0" No_argument       "u" */
+                "date\0"      Required_argument "d"
                 "reference\0" Required_argument "r"
                 ;
 #endif
@@ -85,6 +85,7 @@ int date_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int date_main(int argc UNUSED_PARAM, char **argv)
 {
         struct tm tm_time;
+        char buf_fmt_dt2str[64];
         time_t tm;
         unsigned opt;
         int ifmt = -1;
@@ -108,8 +109,8 @@ int date_main(int argc UNUSED_PARAM, char **argv)
                 ifmt = 0; /* default is date */
                 if (isofmt_arg) {
                         static const char isoformats[] ALIGN1 =
-                                "date\0""hours\0""minutes\0""seconds\0";
-                        ifmt = index_in_strings(isoformats, isofmt_arg);
+                                "date\0""hours\0""minutes\0""seconds\0"; /* ns? */
+                        ifmt = index_in_substrings(isoformats, isofmt_arg);
                         if (ifmt < 0)
                                 bb_show_usage();
                 }
@@ -117,14 +118,14 @@ int date_main(int argc UNUSED_PARAM, char **argv)
 
         fmt_dt2str = NULL;
         if (argv[0] && argv[0][0] == '+') {
-                fmt_dt2str = &argv[0][1];       /* Skip over the '+' */
+                fmt_dt2str = &argv[0][1]; /* skip over the '+' */
                 argv++;
         }
         if (!(opt & (OPT_SET | OPT_DATE))) {
                 opt |= OPT_SET;
                 date_str = argv[0]; /* can be NULL */
                 if (date_str) {
-#if ENABLE_DESKTOP
+#if ENABLE_FEATURE_DATE_COMPAT
                         int len = strspn(date_str, "0123456789");
                         if (date_str[len] == '\0'
                          || (date_str[len] == '.'
@@ -133,7 +134,7 @@ int date_main(int argc UNUSED_PARAM, char **argv)
                             && date_str[len+3] == '\0'
                             )
                         ) {
-                                /* Dreaded [MMDDhhmm[[CC]YY][.ss]] format!
+                                /* Dreaded MMDDhhmm[[CC]YY][.ss] format!
                                  * It does not match -d or -s format.
                                  * Some users actually do use it.
                                  */
@@ -155,7 +156,7 @@ int date_main(int argc UNUSED_PARAM, char **argv)
                 bb_show_usage();
 
         /* Now we have parsed all the information except the date format
-           which depends on whether the clock is being set or read */
+         * which depends on whether the clock is being set or read */
 
         if (opt & OPT_REFERENCE) {
                 struct stat statbuf;
@@ -198,37 +199,28 @@ int date_main(int argc UNUSED_PARAM, char **argv)
         /* Deal with format string */
         if (fmt_dt2str == NULL) {
                 int i;
-                fmt_dt2str = xzalloc(32);
+                fmt_dt2str = buf_fmt_dt2str;
                 if (ENABLE_FEATURE_DATE_ISOFMT && ifmt >= 0) {
-                        strcpy(fmt_dt2str, "%Y-%m-%d");
-                        if (ifmt > 0) {
-                                i = 8;
-                                fmt_dt2str[i++] = 'T';
-                                fmt_dt2str[i++] = '%';
-                                fmt_dt2str[i++] = 'H';
-                                if (ifmt > 1) {
-                                        fmt_dt2str[i++] = ':';
-                                        fmt_dt2str[i++] = '%';
-                                        fmt_dt2str[i++] = 'M';
-                                        if (ifmt > 2) {
-                                                fmt_dt2str[i++] = ':';
-                                                fmt_dt2str[i++] = '%';
-                                                fmt_dt2str[i++] = 'S';
-                                        }
-                                }
+                        /* -I[SPEC]: 0:date 1:hours 2:minutes 3:seconds */
+                        strcpy(fmt_dt2str, "%Y-%m-%dT%H:%M:%S");
+                        i = 8 + 3 * ifmt;
+                        if (ifmt != 0) {
+                                /* TODO: if (ifmt==4) i += sprintf(&fmt_dt2str[i], ",%09u", nanoseconds); */
  format_utc:
                                 fmt_dt2str[i++] = '%';
-                                fmt_dt2str[i] = (opt & OPT_UTC) ? 'Z' : 'z';
+                                fmt_dt2str[i++] = (opt & OPT_UTC) ? 'Z' : 'z';
                         }
+                        fmt_dt2str[i] = '\0';
                 } else if (opt & OPT_RFC2822) {
-                        /* Undo busybox.c for date -R */
+                        /* -R. undo busybox.c setlocale */
                         if (ENABLE_LOCALE_SUPPORT)
                                 setlocale(LC_TIME, "C");
                         strcpy(fmt_dt2str, "%a, %d %b %Y %H:%M:%S ");
-                        i = 22;
+                        i = sizeof("%a, %d %b %Y %H:%M:%S ")-1;
                         goto format_utc;
-                } else /* default case */
+                } else { /* default case */
                         fmt_dt2str = (char*)"%a %b %e %H:%M:%S %Z %Y";
+                }
         }
 
 #define date_buf bb_common_bufsiz1
@@ -240,7 +232,6 @@ int date_main(int argc UNUSED_PARAM, char **argv)
                 if (strncmp(fmt_dt2str, "%f", 2) == 0) {
                         fmt_dt2str = (char*)"%Y.%m.%d-%H:%M:%S";
                 }
-
                 /* Generate output string */
                 strftime(date_buf, sizeof(date_buf), fmt_dt2str, &tm_time);
         }