lib: don't assume time_t is signed.

We introduce the function c_time to convert a Lisp integer
to time_t, and num_time to do the reverse conversion.
The FFI type time-t already does this right.
(See registration of time-t in ffi_init_extra_types).

* hash.c (gen_hash_seed): The first value out of time_sec_usec
corresponds to a time_t value. We now convert this to C number
using c_time rather than c_num. Also, while we are touching
this code, the microseconds value can convert directly to
ucnum with c_unum.

* lib.c (time_sec_usec): Use num_time for seconds.
(time_string_local, time_string_utc, time_fields_local,
time_fields_utc, time_struct_local, time_struct_utc): Use c_time.
(make_time_impl, time_parse_utc): Use num_time instead of num.

* signal.h (getitimer_wrap, setitimer_wrap): Convert tv_sec
members of struct timeval using c_time and num_time.

* sysif.c (c_time, num_time): New functions.
(stat_to_struct): Convert st_atime, st_mtime and st_ctime
to Lisp using num_time instead of num.

* sysif.c (c_time, num_time): Declared.

1 files changed, 13 insertions, 3 deletions

diff --git a/sysif.c b/sysif.c
index 667e3ad9..7ff7e816 100644
--- a/sysif.c
+++ b/sysif.c
@@ -778,6 +778,16 @@ static int w_fstat(val stream, struct stat *buf)
 }
 #endif
 
+time_t c_time(val time)
+{
+  return if3(convert(time_t, -1) > 0, c_unum(time), c_num(time));
+}
+
+val num_time(time_t time)
+{
+  return if3(convert(time_t, -1) > 0, unum(time), num(time));
+}
+
 #if HAVE_SYS_STAT
 static val stat_to_list(struct stat st)
 {
@@ -821,9 +831,9 @@ val stat_to_struct(struct stat st, val path)
   slotset(strct, blksize_s, zero);
   slotset(strct, blocks_s, zero);
 #endif
-  slotset(strct, atime_s, num(st.st_atime));
-  slotset(strct, mtime_s, num(st.st_mtime));
-  slotset(strct, ctime_s, num(st.st_ctime));
+  slotset(strct, atime_s, num_time(st.st_atime));
+  slotset(strct, mtime_s, num_time(st.st_mtime));
+  slotset(strct, ctime_s, num_time(st.st_ctime));
 #if HAVE_STAT_NSEC
   slotset(strct, atime_nsec_s, num(st.st_atim.tv_nsec));
   slotset(strct, mtime_nsec_s, num(st.st_mtim.tv_nsec));