From e3c72052c108c312d9a8a1d9bad7f8bae9a9e2c3 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Wed, 7 Oct 2020 07:28:43 -0700
Subject: New function: time-nsec.

* configure: Test for clock_gettime, generating
HAVE_CLOCK_GETTIME symbol in config.h.

* time.c (time_sec_nsec): New function.
(time_init): time-nsec intrinsic registered.

* time.h (time_sec_nsec): Declared.

* txr.1: Documented.
---
 configure | 20 ++++++++++++++++++++
 time.c    | 17 +++++++++++++++++
 time.h    |  1 +
 txr.1     | 17 ++++++++++++++++-
 4 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index 92e8715d..edbf398b 100755
--- a/configure
+++ b/configure
@@ -3593,6 +3593,26 @@ else
   printf "no\n"
 fi
 
+printf "Checking for clock_gettime ... "
+cat > conftest.c <<!
+#include <time.h>
+
+int main(void)
+{
+  struct timespec ts;
+  (void) clock_gettime(CLOCK_REALTIME, &ts);
+  return 0;
+}
+!
+
+if conftest ; then
+  printf "yes\n"
+  printf "#define HAVE_CLOCK_GETTIME 1\n" >> config.h
+  have_sys_types=y
+else
+  printf "no\n"
+fi
+
 printf "Checking for loff_t ... "
 cat > conftest.c <<!
 #include <sys/types.h>
diff --git a/time.c b/time.c
index a24255b7..07d2d695 100644
--- a/time.c
+++ b/time.c
@@ -63,6 +63,22 @@ val time_sec_usec(void)
   return cons(num_time(tv.tv_sec), num(tv.tv_usec));
 }
 
+val time_sec_nsec(void)
+{
+#if HAVE_CLOCK_GETTIME
+  struct timespec ts;
+  if (clock_gettime(CLOCK_REALTIME, &ts) == -1)
+    return nil;
+  return cons(num_time(ts.tv_sec), num(ts.tv_nsec));
+#else
+  struct timeval tv;
+  if (gettimeofday(&tv, 0) == -1)
+    return nil;
+  return cons(num_time(tv.tv_sec), num(1000 * tv.tv_usec));
+#endif
+}
+
+
 #if !HAVE_GMTIME_R
 struct tm *gmtime_r(const time_t *timep, struct tm *result);
 struct tm *localtime_r(const time_t *timep, struct tm *result);
@@ -497,6 +513,7 @@ void time_init(void)
 
   reg_fun(intern(lit("time"), user_package), func_n0(time_sec));
   reg_fun(intern(lit("time-usec"), user_package), func_n0(time_sec_usec));
+  reg_fun(intern(lit("time-nsec"), user_package), func_n0(time_sec_nsec));
   reg_fun(intern(lit("time-string-local"), user_package), func_n2(time_string_local));
   reg_fun(intern(lit("time-string-utc"), user_package), func_n2(time_string_utc));
   reg_fun(intern(lit("time-fields-local"), user_package), func_n1(time_fields_local));
diff --git a/time.h b/time.h
index e05691a6..b33531d6 100644
--- a/time.h
+++ b/time.h
@@ -31,6 +31,7 @@ extern val dst_s, gmtoff_s, zone_s;
 
 val time_sec(void);
 val time_sec_usec(void);
+val time_sec_nsec(void);
 val time_string_local(val time, val format);
 val time_string_utc(val time, val format);
 val time_fields_local(val time);
diff --git a/txr.1 b/txr.1
index b08edbfd..395697c3 100644
--- a/txr.1
+++ b/txr.1
@@ -55976,10 +55976,11 @@ parameter, which defaults to the value of
 .codn *random-state* .
 
 .SS* Time
-.coNP Functions @ time and @ time-usec
+.coNP Functions @, time @ time-usec and @ time-nsec
 .synb
 .mets (time)
 .mets (time-usec)
+.mets (time-nsec)
 .syne
 .desc
 The
@@ -55998,6 +55999,20 @@ field holds the seconds measured in the same way, and whose
 field extends the precision by giving
 number of microseconds as an integer value between 0 and 999999.
 
+The
+.code time-nsec
+function is similar to
+.code time-usec
+except that the returned cons cell's
+.code cdr
+field gives a number of nanoseconds as an integer value
+between 0 and 999999999.
+
+Note: on hosts where obtaining nanosecond precision is not available, the
+.code time-nsec
+function obtains a microseconds value instead, and multiplies
+it by 1000.
+
 .coNP Functions @ time-string-local and @ time-string-utc
 .synb
 .mets (time-string-local < time << format )
-- 
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