lib/timeutils: add strxxx_iso() functions

Signed-off-by: Karel Zak <kzak@redhat.com>

include/strutils.h

@@ -212,6 +212,8 @@ static inline size_t ltrim_whitespace(unsigned char *str)
 
 extern char *strnappend(const char *s, const char *suffix, size_t b);
 extern char *strappend(const char *s, const char *suffix);
+extern char *strfappend(const char *s, const char *format, ...)
+		 __attribute__ ((__format__ (__printf__, 2, 0)));
 extern const char *split(const char **state, size_t *l, const char *separator, int quoted);
 
 extern int skip_fline(FILE *fp);

include/timeutils.h

@@ -23,6 +23,7 @@
 
 #include <stdio.h>
 #include <inttypes.h>
+#include <sys/time.h>
 
 typedef uint64_t usec_t;
 typedef uint64_t nsec_t;
@@ -53,4 +54,16 @@ typedef uint64_t nsec_t;
 
 int parse_timestamp(const char *t, usec_t *usec);
 
+/* flags for strxxx_iso() functions */
+enum {
+	ISO_8601_DATE		= (1 << 1),
+	ISO_8601_TIME		= (1 << 2),
+	ISO_8601_USEC		= (1 << 3),
+	ISO_8601_TIMEZONE	= (1 << 4),
+	ISO_8601_SPACE		= (1 << 5)
+};
+char *strtimeval_iso(struct timeval *tv, int flags);
+char *strtm_iso(struct tm *tm, int flags);
+char *strtime_iso(time_t t, int flags);
+
 #endif /* UTIL_LINUX_TIME_UTIL_H */

lib/Makemodule.am

@@ -60,7 +60,8 @@ check_PROGRAMS += \
 	test_mangle \
 	test_randutils \
 	test_strutils \
-	test_ttyutils
+	test_ttyutils \
+	test_timeutils
 
 
 
@@ -125,3 +126,5 @@ test_fileutils_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM
 test_canonicalize_SOURCES = lib/canonicalize.c
 test_canonicalize_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_CANONICALIZE
 
+test_timeutils_SOURCES = lib/timeutils.c lib/strutils.c
+test_timeutils_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_TIMEUTILS

lib/strutils.c

@@ -816,6 +816,23 @@ char *strappend(const char *s, const char *suffix)
         return strnappend(s, suffix, suffix ? strlen(suffix) : 0);
 }
 
+char *strfappend(const char *s, const char *format, ...)
+{
+	va_list ap;
+	char *val, *res;
+	int sz;
+
+	va_start(ap, format);
+	sz = vasprintf(&val, format, ap);
+	va_end(ap);
+
+	if (sz < 0)
+		return NULL;
+
+	res = strnappend(s, val, sz);
+	free(val);
+	return res;
+}
 
 static size_t strcspn_escaped(const char *s, const char *reject)
 {

lib/timeutils.c

@@ -338,3 +338,84 @@ int parse_timestamp(const char *t, usec_t *usec)
 
 	return 0;
 }
+
+static char *format_iso_time(struct tm *tm, suseconds_t usec, int flags)
+{
+	char *s = NULL;
+
+	if (flags & ISO_8601_DATE)
+		s = strfappend(s, "%4d-%.2d-%.2d", tm->tm_year + 1900,
+						tm->tm_mon + 1, tm->tm_mday);
+	if ((flags & ISO_8601_DATE) && (flags & ISO_8601_TIME))
+		s = strnappend(s, (flags & ISO_8601_SPACE) ? " " : "T", 1);
+
+	if (flags & ISO_8601_TIME)
+		s = strfappend(s, "%02d:%02d:%02d", tm->tm_hour,
+						 tm->tm_min, tm->tm_sec);
+	if (flags & ISO_8601_USEC)
+		s = strfappend(s, ".%06ld", (long) usec);
+
+	if (flags & ISO_8601_TIMEZONE) {
+	        int zhour = - timezone / 60 / 60;
+		int zmin = labs(timezone / 60 % 60);
+
+		s = strfappend(s, "%+02d:%02d", zhour, zmin);
+	}
+
+	return s;
+}
+
+char *strtimeval_iso(struct timeval *tv, int flags)
+{
+	struct tm tm = *localtime(&tv->tv_sec);
+	return format_iso_time(&tm, tv->tv_usec, flags);
+}
+
+char *strtm_iso(struct tm *tm, int flags)
+{
+	return format_iso_time(tm, 0, flags);
+}
+
+char *strtime_iso(time_t t, int flags)
+{
+	struct tm tm = *localtime(&t);
+	return format_iso_time(&tm, 0, flags);
+}
+
+
+#ifdef TEST_PROGRAM_TIMEUTILS
+
+int main(int argc, char *argv[])
+{
+	struct timeval tv = { 0 };
+	char *p;
+
+	if (argc < 2) {
+		fprintf(stderr, "usage: %s <time> [<usec>]\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	tv.tv_sec = strtos64_or_err(argv[1], "failed to parse <time>");
+	if (argc == 3)
+		tv.tv_usec = strtos64_or_err(argv[2], "failed to parse <usec>");
+
+	p = strtimeval_iso(&tv, ISO_8601_DATE);
+	printf("Date: '%s'\n", p);
+	free(p);
+
+	p = strtimeval_iso(&tv, ISO_8601_TIME);
+	printf("Time: '%s'\n", p);
+	free(p);
+
+	p = strtimeval_iso(&tv, ISO_8601_DATE | ISO_8601_TIME | ISO_8601_USEC);
+	printf("Full: '%s'\n", p);
+	free(p);
+
+	p = strtimeval_iso(&tv, ISO_8601_DATE | ISO_8601_TIME | ISO_8601_USEC | ISO_8601_TIMEZONE | ISO_8601_SPACE);
+	printf("Zone: '%s'\n", p);
+	free(p);
+
+	return EXIT_SUCCESS;
+}
+
+#endif /* TEST_PROGRAM */