Add timeconv module from FreeBSD

Inline license information from FreeBSD root dir COPYRIGHT file.

src/Makefile.am

@@ -73,6 +73,7 @@ libbsd_la_SOURCES = \
 	strmode.c \
 	strnstr.c \
 	strtonum.c \
+	timeconv.c \
 	unvis.c \
 	vis.c \
 	wcslcat.c \

src/libbsd.map

@@ -113,4 +113,13 @@ LIBBSD_0.6 {
 
 LIBBSD_0.7 {
     funopen;
+
+    _time32_to_time;
+    _time_to_time32;
+    _time64_to_time;
+    _time_to_time64;
+    _time_to_long;
+    _long_to_time;
+    _time_to_int;
+    _int_to_time;
 } LIBBSD_0.6;

src/timeconv.c

@@ -0,0 +1,119 @@
+/*-
+ * Copyright (c) 2001 FreeBSD Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * These routines are for converting time_t to fixed-bit representations
+ * for use in protocols or storage.  When converting time to a larger
+ * representation of time_t these routines are expected to assume temporal
+ * locality and use the 50-year rule to properly set the msb bits.  XXX
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <timeconv.h>
+
+/*
+ * Convert a 32 bit representation of time_t into time_t.  XXX needs to
+ * implement the 50-year rule to handle post-2038 conversions.
+ */
+time_t
+_time32_to_time(int32_t t32)
+{
+    return((time_t)t32);
+}
+
+/*
+ * Convert time_t to a 32 bit representation.  If time_t is 64 bits we can
+ * simply chop it down.   The resulting 32 bit representation can be
+ * converted back to a temporally local 64 bit time_t using time32_to_time.
+ */
+int32_t
+_time_to_time32(time_t t)
+{
+    return((int32_t)t);
+}
+
+/*
+ * Convert a 64 bit representation of time_t into time_t.  If time_t is
+ * represented as 32 bits we can simply chop it and not support times
+ * past 2038.
+ */
+time_t
+_time64_to_time(int64_t t64)
+{
+    return((time_t)t64);
+}
+
+/*
+ * Convert time_t to a 64 bit representation.  If time_t is represented
+ * as 32 bits we simply sign-extend and do not support times past 2038.
+ */
+int64_t
+_time_to_time64(time_t t)
+{
+    return((int64_t)t);
+}
+
+/*
+ * Convert to/from 'long'.  Depending on the sizeof(long) this may or
+ * may not require using the 50-year rule.
+ */
+long
+_time_to_long(time_t t)
+{
+    if (sizeof(long) == sizeof(int64_t))
+	return(_time_to_time64(t));
+    return((long)t);
+}
+
+time_t
+_long_to_time(long tlong)
+{
+    if (sizeof(long) == sizeof(int32_t))
+	return(_time32_to_time(tlong));
+    return((time_t)tlong);
+}
+
+/*
+ * Convert to/from 'int'.  Depending on the sizeof(int) this may or
+ * may not require using the 50-year rule.
+ */
+int
+_time_to_int(time_t t)
+{
+    if (sizeof(int) == sizeof(int64_t))
+	return(_time_to_time64(t));
+    return((int)t);
+}
+
+time_t
+_int_to_time(int tint)
+{
+    if (sizeof(int) == sizeof(int32_t))
+	return(_time32_to_time(tint));
+    return((time_t)tint);
+}