From 89a9a4f613a6b4f1bccddec6f01c3af317398132 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Mon, 22 Aug 2016 20:32:21 -0700
Subject: Adding time-parse function: wrapper for strptime.

* configure: Test for strptime.

* eval.c (eval_init): register time-parse intrinsic.

* lib.c (time_parse): New function.

* lib.h (time_parse): Declared.

* txr.1: Documented.
---
 configure | 18 ++++++++++++++++++
 eval.c    |  1 +
 lib.c     | 18 ++++++++++++++++++
 lib.h     |  3 +++
 txr.1     | 28 ++++++++++++++++++++++++++++
 5 files changed, 68 insertions(+)

diff --git a/configure b/configure
index cbbe2369..f3ec930b 100755
--- a/configure
+++ b/configure
@@ -1688,6 +1688,24 @@ else
   printf "no\n"
 fi
 
+printf "Checking for strptime function ... "
+
+cat > conftest.c <<!
+#include <time.h>
+
+int main(int argc, char **argv)
+{
+  struct tm stm = { 0 };
+  strptime("2016-08-20 00:00:00", "%Y-%m-%d %H:%M:%S", &stm);
+  return 0;
+}
+!
+if conftest ; then
+  printf "yes\n"
+  printf "#define HAVE_STRPTIME 1\n" >> $config_h
+else
+  printf "no\n"
+fi
 
 printf "Checking for POSIX sleep function ... "
 
diff --git a/eval.c b/eval.c
index 39ee9652..78cc5a34 100644
--- a/eval.c
+++ b/eval.c
@@ -5337,6 +5337,7 @@ void eval_init(void)
   reg_fun(intern(lit("time-struct-utc"), user_package), func_n1(time_struct_utc));
   reg_fun(intern(lit("make-time"), user_package), func_n7(make_time));
   reg_fun(intern(lit("make-time-utc"), user_package), func_n7(make_time_utc));
+  reg_fun(intern(lit("time-parse"), user_package), func_n2(time_parse));
 
   reg_fun(intern(lit("source-loc"), user_package), func_n1(source_loc));
   reg_fun(intern(lit("source-loc-str"), user_package), func_n2o(source_loc_str, 1));
diff --git a/lib.c b/lib.c
index d497eb20..6352eb2a 100644
--- a/lib.c
+++ b/lib.c
@@ -9374,6 +9374,24 @@ val make_time(val year, val month, val day,
   return make_time_impl(mktime, year, month, day, hour, minute, second, isdst);
 }
 
+#if HAVE_STRPTIME
+
+val time_parse(val format, val string)
+{
+  struct tm tms = { 0 };
+  const wchar_t *w_str = c_str(string);
+  const wchar_t *w_fmt = c_str(format);
+  char *str = utf8_dup_to(w_str);
+  char *fmt = utf8_dup_to(w_fmt);
+  char *ptr = strptime(str, fmt, &tms);
+  int ret = ptr != 0;
+  free(fmt);
+  free(str);
+  return ret ? broken_time_struct(&tms) : nil;
+}
+
+#endif
+
 #if !HAVE_SETENV
 
 void setenv(const char *name, const char *value, int overwrite)
diff --git a/lib.h b/lib.h
index c815658a..0785639f 100644
--- a/lib.h
+++ b/lib.h
@@ -992,6 +992,9 @@ val make_time(val year, val month, val day,
 val make_time_utc(val year, val month, val day,
                   val hour, val minute, val second,
                   val isdst);
+#if HAVE_STRPTIME
+val time_parse(val format, val string);
+#endif
 
 void init(mem_t *(*oom_realloc)(mem_t *, size_t), val *stack_bottom);
 int compat_fixup(int compat_ver);
diff --git a/txr.1 b/txr.1
index 3c824e57..44141f12 100644
--- a/txr.1
+++ b/txr.1
@@ -36516,6 +36516,34 @@ function or from the
 .code time-usec
 function.
 
+.coNP Function @ time-parse
+.synb
+.mets (time-parse < format << string )
+.syne
+.desc
+The
+.code time-parse
+function scans a time description in
+.meta string
+according to the specification given in the
+.meta format
+string. If the scan is successful, a structure
+of type
+.code time
+is returned, otherwise
+.codn nil .
+
+The
+.meta format
+argument follows the same conventions as the POSIX
+C library function
+.codn strptime .
+
+Note: the availability of
+.code time-parse
+depends on the availability of
+.codn strptime .
+
 .coNP Methods @ time-local and @ time-utc
 .synb
 .mets << time-struct .(time-local)
-- 
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