libbb: introduce and use strftime_[YYYYMMDD]HHMMSS()

function                                             old     new   delta
strftime_fmt                                           -      53     +53
strftime_YYYYMMDDHHMMSS                                -      12     +12
strftime_HHMMSS                                        -      12     +12
human_time                                            44      43      -1
fmtstr_t                                               9       -      -9
step_time                                            361     345     -16
watch_main                                           261     232     -29
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 0/3 up/down: 77/-55)             Total: 22 bytes
   text	   data	    bss	    dec	    hex	filename
 919203	    932	  17692	 937827	  e4f63	busybox_old
 919209	    932	  17692	 937833	  e4f69	busybox_unstripped

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

1 files changed, 21 insertions, 0 deletions

diff --git a/libbb/time.c b/libbb/time.c
index e2b938471..57e14b66c 100644
--- a/libbb/time.c
+++ b/libbb/time.c
@@ -187,6 +187,27 @@ time_t FAST_FUNC validate_tm_time(const char *date_str, struct tm *ptm)
         return t;
 }
 
+static char* strftime_fmt(char *buf, unsigned len, time_t *tp, const char *fmt)
+{
+        time_t t;
+        if (!tp) {
+                tp = &t;
+                time(tp);
+        }
+        /* Returns pointer to NUL */
+        return buf + strftime(buf, len, fmt, localtime(tp));
+}
+
+char* FAST_FUNC strftime_HHMMSS(char *buf, unsigned len, time_t *tp)
+{
+        return strftime_fmt(buf, len, tp, "%H:%M:%S");
+}
+
+char* FAST_FUNC strftime_YYYYMMDDHHMMSS(char *buf, unsigned len, time_t *tp)
+{
+        return strftime_fmt(buf, len, tp, "%Y-%m-%d %H:%M:%S");
+}
+
 #if ENABLE_MONOTONIC_SYSCALL
 
 #include <sys/syscall.h>