lib-imap: fix for systems with signed 32-bit time_t

The code and tests have some hard-coded values based on the size of
time_t but they don't take into account whether or not time_t is a
signed value.

On systems such as i686 with time_t as a signed 32-bit integer, the
maximum value is the same as an unsigned 31-bit integer. Adjust the
code to account for this.

Author: pghmcfc

src/lib-imap/imap-date.c

@@ -86,9 +86,17 @@ static bool tm_is_too_large(const struct tm *tm, time_t *max_time_r)
 
 	if (max_time == 0) {
 #if TIME_T_MAX_BITS == 32
+#ifdef TIME_T_SIGNED
+		max_time = 0x7fffffffL;
+#else
 		max_time = 0xffffffffUL;
+#endif
 #elif TIME_T_MAX_BITS == 64
+#ifdef TIME_T_SIGNED
+		max_time = 0x7fffffffffffffffLL;
+#else
 		max_time = 0xffffffffffffffffULL;
+#endif
 #else
 		max_time = ((time_t)1 << TIME_T_MAX_BITS) - 1;
 #endif

src/lib-imap/test-imap-date.c

@@ -15,7 +15,7 @@ static void test_imap_date(void)
 	} tests[] = {
 		{ "01-Jan-1970", 0 },
 		{ "19-Jan-2038", 2147472000 },
-#if TIME_T_MAX_BITS >= 32
+#if TIME_T_MAX_BITS > 32 || (TIME_T_MAX_BITS == 32 && !defined(TIME_T_SIGNED))
 		{ "07-Feb-2106", 4294944000 },
 #endif
 #if TIME_T_MAX_BITS >= 37
@@ -25,7 +25,7 @@ static void test_imap_date(void)
 		{ "31-Dec-9999", 253402214400LL },
 #endif
 		/* conversions to maximum values */
-#if TIME_T_MAX_BITS == 31
+#if TIME_T_MAX_BITS == 31 || (TIME_T_MAX_BITS == 32 && defined(TIME_T_SIGNED))
 		{ "20-Jan-2038", 2147483647 },
 		{ "31-Dec-9999", 2147483647 },
 #elif TIME_T_MAX_BITS == 32
@@ -60,7 +60,7 @@ static void test_imap_datetime(void)
 		{ "01-Jan-1970 00:00:00 +0000", 0, 0 },
 		{ "19-Jan-2038 03:14:07 +0000", 2147483647, 0 },
 		{ "19-Jan-2038 05:14:07 +0200", 2147483647, 2*60 },
-#if TIME_T_MAX_BITS >= 32
+#if TIME_T_MAX_BITS > 32 || (TIME_T_MAX_BITS == 32 && !defined(TIME_T_SIGNED))
 		{ "07-Feb-2106 06:28:15 +0000", 4294967295, 0 },
 #endif
 #if TIME_T_MAX_BITS >= 37
@@ -71,7 +71,7 @@ static void test_imap_datetime(void)
 		{ "31-Dec-9999 23:59:59 -2359", 253402300799LL + 23*60*60 + 59*60, -23*60 - 59 },
 #endif
 		/* conversions to maximum values */
-#if TIME_T_MAX_BITS == 31
+#if TIME_T_MAX_BITS == 31 || (TIME_T_MAX_BITS == 32 && defined(TIME_T_SIGNED))
 		{ "19-Jan-2038 03:14:08 +0000", 2147483647, 0 },
 		{ "31-Dec-9999 23:59:59 -2359", 2147483647, -23*60 - 59 },
 #elif TIME_T_MAX_BITS == 32