Implement mktime() function for compatibility with mawk and gawk.

This is the only missing time function compared to those two
implementations.  Doc changes OK jmc@

4 files changed, 66 insertions, 6 deletions

diff --git a/usr.bin/awk/awk.1 b/usr.bin/awk/awk.1
index 2fbaf6680f5..a902f2d44b4 100644
--- a/usr.bin/awk/awk.1
+++ b/usr.bin/awk/awk.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: awk.1,v 1.56 2020/07/24 01:57:06 millert Exp $
+.\"	$OpenBSD: awk.1,v 1.57 2020/08/28 16:29:16 millert Exp $
 .\"
 .\" Copyright (C) Lucent Technologies 1997
 .\" All Rights Reserved
@@ -22,7 +22,7 @@
 .\" ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
 .\" THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: July 24 2020 $
+.Dd $Mdocdate: August 28 2020 $
 .Dt AWK 1
 .Os
 .Sh NAME
@@ -684,6 +684,41 @@ This version of
 provides the following functions for obtaining and formatting time
 stamps.
 .Bl -tag -width indent
+.It Fn mktime datespec
+Converts
+.Fa datespec
+into a timestamp in the same form as a value returned by
+.Fn systime .
+The
+.Fa datespec
+is a string composed of six or seven numbers separated by whitespace:
+.Bd -literal -offset indent
+YYYY MM DD HH MM SS [DST]
+.Ed
+.Pp
+The fields in
+.Fa datespec
+are as follows:
+.Bl -tag -width "YYYY"
+.It YYY
+Year: a four-digit year, including the century.
+.It MM
+Month: a number from 1 to 12.
+.It DD
+Day: a number from 1 to 31.
+.It HH
+Hour: a number from 0 to 23.
+.It MM
+Minute: a number from 0 to 59.
+.It SS
+Second: a number from 0 to 60 (permitting a leap second).
+.It DST
+Daylight Saving Time: a positive or zero value indicates that
+DST is or is not in effect.
+If DST is not specified, or is negative,
+.Fn mktime
+will attempt to determine the correct value.
+.El
 .It Fn strftime "[format [, timestamp]]"
 Formats
 .Ar timestamp
@@ -696,6 +731,8 @@ manual page, as well as any arbitrary text.
 The
 .Ar timestamp
 must be in the same form as a value returned by
+.Fn mktime
+and
 .Fn systime .
 If
 .Ar timestamp
@@ -935,6 +972,7 @@ as well as the functions
 .Fn xor ,
 .Fn lshift ,
 .Fn rshift ,
+.Fn mktime ,
 .Fn strftime
 and
 .Fn systime
diff --git a/usr.bin/awk/awk.h b/usr.bin/awk/awk.h
index 68e03a809c6..25dfec2fcc4 100644
--- a/usr.bin/awk/awk.h
+++ b/usr.bin/awk/awk.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: awk.h,v 1.26 2020/06/26 15:57:39 millert Exp $	*/
+/*	$OpenBSD: awk.h,v 1.27 2020/08/28 16:29:16 millert Exp $	*/
 /****************************************************************
 Copyright (C) Lucent Technologies 1997
 All Rights Reserved
@@ -160,6 +160,7 @@ extern Cell	*symtabloc;	/* SYMTAB */
 #define FRSHIFT	20
 #define FSYSTIME	21
 #define FSTRFTIME	22
+#define FMKTIME	23
 
 /* Node:  parse tree is made of nodes, with Cell's at bottom */
 
diff --git a/usr.bin/awk/lex.c b/usr.bin/awk/lex.c
index 6a835c24cb1..1dc1f991fa0 100644
--- a/usr.bin/awk/lex.c
+++ b/usr.bin/awk/lex.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lex.c,v 1.25 2020/07/30 17:45:44 millert Exp $	*/
+/*	$OpenBSD: lex.c,v 1.26 2020/08/28 16:29:16 millert Exp $	*/
 /****************************************************************
 Copyright (C) Lucent Technologies 1997
 All Rights Reserved
@@ -75,6 +75,7 @@ const Keyword keywords[] = {	/* keep sorted: binary searched */
 	{ "log",	FLOG,		BLTIN },
 	{ "lshift",	FLSHIFT,	BLTIN },
 	{ "match",	MATCHFCN,	MATCHFCN },
+	{ "mktime",	FMKTIME,	BLTIN },
 	{ "next",	NEXT,		NEXT },
 	{ "nextfile",	NEXTFILE,	NEXTFILE },
 	{ "or",		FFOR,		BLTIN },
diff --git a/usr.bin/awk/run.c b/usr.bin/awk/run.c
index dcd959aa52d..f6b141c695c 100644
--- a/usr.bin/awk/run.c
+++ b/usr.bin/awk/run.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: run.c,v 1.67 2020/08/11 16:57:05 millert Exp $	*/
+/*	$OpenBSD: run.c,v 1.68 2020/08/28 16:29:16 millert Exp $	*/
 /****************************************************************
 Copyright (C) Lucent Technologies 1997
 All Rights Reserved
@@ -1594,7 +1594,7 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 	FILE *fp;
 	int status = 0;
 	time_t tv;
-	struct tm *tm;
+	struct tm *tm, tmbuf;
 
 	t = ptoi(a[0]);
 	x = execute(a[1]);
@@ -1749,6 +1749,26 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 		else
 			u = fflush(fp);
 		break;
+	case FMKTIME:
+		memset(&tmbuf, 0, sizeof(tmbuf));
+		tm = &tmbuf;
+		t = sscanf(getsval(x), "%d %d %d %d %d %d %d",
+		    &tm->tm_year, &tm->tm_mon, &tm->tm_mday, &tm->tm_hour,
+		    &tm->tm_min, &tm->tm_sec, &tm->tm_isdst);
+		switch (t) {
+		case 6:
+			tm->tm_isdst = -1;	/* let mktime figure it out */
+			/* FALLTHROUGH */
+		case 7:
+			tm->tm_year -= 1900;
+			tm->tm_mon--;
+			u = mktime(tm);
+			break;
+		default:
+			u = -1;
+			break;
+		}
+		break;
 	case FSYSTIME:
 		u = time((time_t *) 0);
 		break;