Add time parse/format functions to libvarnish

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@189 d4fa192b-c00b-0410-8231-f00ffab90ce4

include/libvarnish.h

@@ -6,6 +6,11 @@
 void FreeArgv(char **argv);
 char **ParseArgv(const char *s, int comment);
 
+#ifdef CLOCK_MONOTONIC
+/* from libvarnish/time.c */
+void TIM_format(time_t t, char *p);
+time_t TIM_parse(const char *p);
+#endif
 
 /* Assert zero return value */
 #define AZ(foo)	do { assert((foo) == 0); } while (0)

lib/libvarnish/Makefile.am

@@ -6,4 +6,5 @@ lib_LTLIBRARIES = libvarnish.la
 
 libvarnish_la_SOURCES = \
 	argv.c \
-	cli.c
+	cli.c \
+	time.c

lib/libvarnish/time.c

+/*
+ * $Id$
+ *
+ * Semi-trivial functions to handle HTTP header timestamps according to
+ * RFC 2616 section 3.3.
+ *
+ * In the highly unlikely event of performance trouble, handbuilt versions
+ * would likely be faster than relying on the OS time functions.
+ *
+ * We must parse three different formats:
+ *       000000000011111111112222222222
+ *       012345678901234567890123456789
+ *       ------------------------------
+ *	"Sun, 06 Nov 1994 08:49:37 GMT"		RFC822 & RFC1123
+ *	"Sunday, 06-Nov-94 08:49:37 GMT"	RFC850
+ *	"Sun Nov  6 08:49:37 1994"		ANSI-C asctime()
+ *
+ * And always output the RFC1123 format.
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+void
+TIM_format(time_t t, char *p)
+{
+	struct tm tm;
+
+	gmtime_r(&t, &tm);
+	strftime(p, 30, "%a, %d %b %Y %T GMT", &tm);
+}
+
+/* XXX: add statistics ? */
+static const char *fmts[] = {
+	"%a, %d %b %Y %T GMT",	/* RFC 822 & RFC1123 */
+	"%A, %d-%b-%y %T GMT",	/* RFC850 */
+	"%a %b %d %T %Y",	/* ANSI-C asctime() */
+	NULL
+};
+
+time_t
+TIM_parse(const char *p)
+{
+	struct tm tm;
+	const char **r;
+
+	for (r = fmts; *r != NULL; r++) {
+		memset(&tm, 0, sizeof tm);
+		if (strptime(p, *r, &tm) != NULL)
+			return(timegm(&tm));
+	}
+	return (0);
+}
+
+#ifdef TEST_DRIVER
+int
+main(int argc, char **argv)
+{
+	time_t t;
+	char buf[BUFSIZ];
+
+	time(&t);
+	memset(buf, 0x55, sizeof buf);
+	TIM_format(t, buf);
+	printf("scan = %d <%s>\n", TIM_parse(buf), buf);
+
+	/* Examples from RFC2616 section 3.3.1 */
+	printf("scan = %d\n", TIM_parse("Sun, 06 Nov 1994 08:49:37 GMT"));
+	printf("scan = %d\n", TIM_parse("Sunday, 06-Nov-94 08:49:37 GMT"));
+	printf("scan = %d\n", TIM_parse("Sun Nov  6 08:49:37 1994"));
+
+	return (0);
+}
+#endif