date: support -Ins, more compatible timezone display in -I

function                                             old     new   delta
date_main                                            941    1016     +75
static.isoformats                                     28      31      +3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 78/0)               Total: 78 bytes

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

1 files changed, 19 insertions, 7 deletions

diff --git a/coreutils/date.c b/coreutils/date.c
index d8a2e8618..7fead01bd 100644
--- a/coreutils/date.c
+++ b/coreutils/date.c
@@ -208,7 +208,7 @@ 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"; /* ns? */
+                                "date\0""hours\0""minutes\0""seconds\0ns\0";
                         ifmt = index_in_substrings(isoformats, isofmt_arg);
                         if (ifmt < 0)
                                 bb_show_usage();
@@ -315,21 +315,33 @@ int date_main(int argc UNUSED_PARAM, char **argv)
                 int i;
                 fmt_dt2str = buf_fmt_dt2str;
                 if (ENABLE_FEATURE_DATE_ISOFMT && ifmt >= 0) {
-                        /* -I[SPEC]: 0:date 1:hours 2:minutes 3:seconds */
+                        /* -I[SPEC]: 0:date 1:hours 2:minutes 3:seconds 4:ns*/
                         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); */
-                                fmt_dt2str[i++] = '%';
-                                fmt_dt2str[i++] = 'z';
-                                /* FIXME: %z prints "+hhmm" timezone, but coreutils-8.30 prints "+hh:mm" */
+                                int n;
+                                if (ifmt == 4) {
+                                        i -= 3;
+                                        i += sprintf(&fmt_dt2str[i], ",%09u", (unsigned)ts.tv_nsec);
+                                }
+                                /* %z prints "+hhmm" timezone, but coreutils-8.30 prints "+hh:mm"! */
+                                /* ...therefore this atrocity: */
+                                n = strftime(&fmt_dt2str[i], 8, "%z", &tm_time);
+                                i += n;
+                                if (n == 5 && (fmt_dt2str[i-5] == '+' || fmt_dt2str[i-5] == '-')) {
+                                        /* "mm" -> ":mm" */
+                                        fmt_dt2str[i    ] = fmt_dt2str[i - 1];
+                                        fmt_dt2str[i - 1] = fmt_dt2str[i - 2];
+                                        fmt_dt2str[i - 2] = ':';
+                                        i++;
+                                }
                         }
                         fmt_dt2str[i] = '\0';
                 } else if (opt & OPT_RFC2822) {
                         /* -R. undo busybox.c setlocale */
                         if (ENABLE_LOCALE_SUPPORT)
                                 setlocale(LC_TIME, "C");
-                        strcpy(fmt_dt2str, "%a, %d %b %Y %H:%M:%S %z");
+                        fmt_dt2str = (char*)"%a, %d %b %Y %H:%M:%S %z";
                 } else { /* default case */
                         fmt_dt2str = (char*)"%a %b %e %H:%M:%S %Z %Y";
                 }