Some improvements in date/time functions

- Range in date table extended to full 32 bits. - Easier support for times represented as floats. - Added more tests.
author: Roberto Ierusalimschy <roberto@inf.puc-rio.br> 2019-07-24 15:01:59 -0300
committer: Roberto Ierusalimschy <roberto@inf.puc-rio.br> 2019-07-24 15:01:59 -0300
commit: 0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42 (patch)
tree: dcf79de5e0efc790142ed7e2fd418813c70d0c60
parent: 7f5c31cdcac5388b3c48a26112dfb6d2cadb7321 (diff)
download: lua-0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42.tar.gz
lua-0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42.tar.bz2
lua-0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42.zip
2 files changed, 100 insertions, 41 deletions
diff --git a/loslib.c b/loslib.c
index 8809e5ea..7812d29b 100644
--- a/loslib.c
+++ b/loslib.c
@@ -58,18 +58,20 @@
 ** ===================================================================
 */
-#if !defined(l_time_t)          /* { */
 /*
 ** type to represent time_t in Lua
 */
+#if !defined(LUA_NUMTIME)       /* { */
 #define l_timet                 lua_Integer
 #define l_pushtime(L,t)         lua_pushinteger(L,(lua_Integer)(t))
+#define l_gettime(L,arg)        luaL_checkinteger(L, arg)
-static time_t l_checktime (lua_State *L, int arg) {
+#else                           /* }{ */
-  lua_Integer t = luaL_checkinteger(L, arg);
-  luaL_argcheck(L, (time_t)t == t, arg, "time out-of-bounds");
+#define l_timet                 lua_Number
-  return (time_t)t;
+#define l_pushtime(L,t)         lua_pushnumber(L,(lua_Number)(t))
-}
+#define l_gettime(L,arg)        luaL_checknumber(L, arg)
 #endif                          /* } */
@@ -193,11 +195,25 @@ static int os_clock (lua_State *L) {
 ** =======================================================
 */
-static void setfield (lua_State *L, const char *key, int value) {
+/*
-  lua_pushinteger(L, value);
+** About the overflow check: an overflow cannot occurr when time
+** is represented by a lua_Integer, because either lua_Integer is
+** large enough to represent all int fields or it is not large enough
+** to represent a time that cause a field to overflow.  However, if
+** times are represented as doubles and lua_Integer is int, then the
+** time 0x1.e1853b0d184f6p+55 would cause an overflow when adding 1900
+** to compute the year.
+*/
+static void setfield (lua_State *L, const char *key, int value, int delta) {
+  #if (defined(LUA_NUMTIME) && LUA_MAXINTEGER <= INT_MAX)
+    if (value > LUA_MAXINTEGER - delta)
+      luaL_error(L, "field '%s' is out-of-bound", key);
+  #endif
+  lua_pushinteger(L, (lua_Integer)value + delta);
  lua_setfield(L, -2, key);
 }
 static void setboolfield (lua_State *L, const char *key, int value) {
  if (value < 0)  /* undefined? */
    return;  /* does not set field */
@@ -210,14 +226,14 @@ static void setboolfield (lua_State *L, const char *key, int value) {
 ** Set all fields from structure 'tm' in the table on top of the stack
 */
 static void setallfields (lua_State *L, struct tm *stm) {
-  setfield(L, "sec", stm->tm_sec);
+  setfield(L, "year", stm->tm_year, 1900);
-  setfield(L, "min", stm->tm_min);
+  setfield(L, "month", stm->tm_mon, 1);
-  setfield(L, "hour", stm->tm_hour);
+  setfield(L, "day", stm->tm_mday, 0);
-  setfield(L, "day", stm->tm_mday);
+  setfield(L, "hour", stm->tm_hour, 0);
-  setfield(L, "month", stm->tm_mon + 1);
+  setfield(L, "min", stm->tm_min, 0);
-  setfield(L, "year", stm->tm_year + 1900);
+  setfield(L, "sec", stm->tm_sec, 0);
-  setfield(L, "wday", stm->tm_wday + 1);
+  setfield(L, "yday", stm->tm_yday, 1);
-  setfield(L, "yday", stm->tm_yday + 1);
+  setfield(L, "wday", stm->tm_wday, 1);
  setboolfield(L, "isdst", stm->tm_isdst);
 }
@@ -230,11 +246,6 @@ static int getboolfield (lua_State *L, const char *key) {
 }
-/* maximum value for date fields (to avoid arithmetic overflows with 'int') */
-#if !defined(L_MAXDATEFIELD)
-#define L_MAXDATEFIELD  (INT_MAX / 2)
-#endif
 static int getfield (lua_State *L, const char *key, int d, int delta) {
  int isnum;
  int t = lua_getfield(L, -1, key);  /* get field and its type */
@@ -247,7 +258,9 @@ static int getfield (lua_State *L, const char *key, int d, int delta) {
    res = d;
  }
  else {
-    if (!(-L_MAXDATEFIELD <= res && res <= L_MAXDATEFIELD))
+    /* unsigned avoids overflow when lua_Integer has 32 bits */
+    if (!(res >= 0 ? (lua_Unsigned)res <= (lua_Unsigned)INT_MAX + delta
+                   : (lua_Integer)INT_MIN + delta <= res))
      return luaL_error(L, "field '%s' is out-of-bound", key);
    res -= delta;
  }
@@ -275,6 +288,13 @@ static const char *checkoption (lua_State *L, const char *conv,
 }
+static time_t l_checktime (lua_State *L, int arg) {
+  l_timet t = l_gettime(L, arg);
+  luaL_argcheck(L, (time_t)t == t, arg, "time out-of-bounds");
+  return (time_t)t;
+}
 /* maximum size for an individual 'strftime' item */
 #define SIZETIMEFMT     250
@@ -293,7 +313,7 @@ static int os_date (lua_State *L) {
    stm = l_localtime(&t, &tmr);
  if (stm == NULL)  /* invalid date? */
    return luaL_error(L,
-                 "time result cannot be represented in this installation");
+                 "date result cannot be represented in this installation");
  if (strcmp(s, "*t") == 0) {
    lua_createtable(L, 0, 9);  /* 9 = number of fields */
    setallfields(L, stm);
@@ -329,12 +349,12 @@ static int os_time (lua_State *L) {
    struct tm ts;
    luaL_checktype(L, 1, LUA_TTABLE);
    lua_settop(L, 1);  /* make sure table is at the top */
-    ts.tm_sec = getfield(L, "sec", 0, 0);
-    ts.tm_min = getfield(L, "min", 0, 0);
-    ts.tm_hour = getfield(L, "hour", 12, 0);
-    ts.tm_mday = getfield(L, "day", -1, 0);
-    ts.tm_mon = getfield(L, "month", -1, 1);
    ts.tm_year = getfield(L, "year", -1, 1900);
+    ts.tm_mon = getfield(L, "month", -1, 1);
+    ts.tm_mday = getfield(L, "day", -1, 0);
+    ts.tm_hour = getfield(L, "hour", 12, 0);
+    ts.tm_min = getfield(L, "min", 0, 0);
+    ts.tm_sec = getfield(L, "sec", 0, 0);
    ts.tm_isdst = getboolfield(L, "isdst");
    t = mktime(&ts);
    setallfields(L, &ts);  /* update fields with normalized values */
diff --git a/testes/files.lua b/testes/files.lua
index c8f23d18..6e7bd9e2 100644
--- a/testes/files.lua
+++ b/testes/files.lua
@@ -775,11 +775,24 @@ assert(os.date(string.rep("%d", 1000), t) ==
       string.rep(os.date("%d", t), 1000))
 assert(os.date(string.rep("%", 200)) == string.rep("%", 100))
-local t = os.time()
+local function checkDateTable (t)
-D = os.date("*t", t)
+  _G.D = os.date("*t", t)
-load(os.date([[assert(D.year==%Y and D.month==%m and D.day==%d and
+  assert(os.time(D) == t)
-  D.hour==%H and D.min==%M and D.sec==%S and
+  load(os.date([[assert(D.year==%Y and D.month==%m and D.day==%d and
-  D.wday==%w+1 and D.yday==%j)]], t))()
+    D.hour==%H and D.min==%M and D.sec==%S and
+    D.wday==%w+1 and D.yday==%j)]], t))()
+  _G.D = nil
+end
+checkDateTable(os.time())
+if not _port then
+  -- assume that time_t can represent these values
+  checkDateTable(0)
+  checkDateTable(1)
+  checkDateTable(1000)
+  checkDateTable(0x7fffffff)
+  checkDateTable(0x80000000)
+end
 checkerr("invalid conversion specifier", os.date, "%")
 checkerr("invalid conversion specifier", os.date, "%9")
@@ -793,11 +806,24 @@ checkerr("not an integer", os.time, {year=1000, month=1, day=1, hour=1.5})
 checkerr("missing", os.time, {hour = 12})   -- missing date
+if string.packsize("i") == 4 then   -- 4-byte ints
+  checkerr("field 'year' is out-of-bound", os.time,
+              {year = -(1 << 31) + 1899, month = 1, day = 1})
+end
 if not _port then
  -- test Posix-specific modifiers
  assert(type(os.date("%Ex")) == 'string')
  assert(type(os.date("%Oy")) == 'string')
+  -- test large dates (assume at least 4-byte ints and time_t)
+  local t0 = os.time{year = 1970, month = 1, day = 0}
+  local t1 = os.time{year = 1970, month = 1, day = 0, sec = (1 << 31) - 1}
+  assert(t1 - t0 == (1 << 31) - 1)
+  t0 = os.time{year = 1970, month = 1, day = 1}
+  t1 = os.time{year = 1970, month = 1, day = 1, sec = -(1 << 31)}
+  assert(t1 - t0 == -(1 << 31))
  -- test out-of-range dates (at least for Unix)
  if maxint >= 2^62 then  -- cannot do these tests in Small Lua
@@ -812,25 +838,37 @@ if not _port then
        -- time_t has 8 bytes; an int year cannot represent a huge time
        print("  8-byte time_t")
        checkerr("cannot be represented", os.date, "%Y", 2^60)
-        -- it should have no problems with year 4000
-        assert(tonumber(os.time{year=4000, month=1, day=1}))
+        -- this is the maximum year
+        assert(tonumber(os.time
+          {year=(1 << 31) + 1899, month=12, day=31, hour=23, min=59, sec=59}))
+        -- this is too much
+        checkerr("represented", os.time,
+          {year=(1 << 31) + 1899, month=12, day=31, hour=23, min=59, sec=60})
      end
+      -- internal 'int' fields cannot hold these values
+      checkerr("field 'day' is out-of-bound", os.time,
+                  {year = 0, month = 1, day = 2^32})
+      checkerr("field 'month' is out-of-bound", os.time,
+                  {year = 0, month = -((1 << 31) + 1), day = 1})
+      checkerr("field 'year' is out-of-bound", os.time,
+                  {year = (1 << 31) + 1900, month = 1, day = 1})
    else    -- 8-byte ints
      -- assume time_t has 8 bytes too
      print("  8-byte time_t")
      assert(tonumber(os.date("%Y", 2^60)))
      -- but still cannot represent a huge year
      checkerr("cannot be represented", os.time, {year=2^60, month=1, day=1})
    end
  end
 end
-D = os.date("!*t", t)
-load(os.date([[!assert(D.year==%Y and D.month==%m and D.day==%d and
-  D.hour==%H and D.min==%M and D.sec==%S and
-  D.wday==%w+1 and D.yday==%j)]], t))()
 do
  local D = os.date("*t")
  local t = os.time(D)
@@ -844,6 +882,7 @@ do
  assert(t == t1)   -- if isdst is absent uses correct default
 end
+local D = os.date("*t")
 t = os.time(D)
 D.year = D.year-1;
 local t1 = os.time(D)
author	Roberto Ierusalimschy <roberto@inf.puc-rio.br>	2019-07-24 15:01:59 -0300
committer	Roberto Ierusalimschy <roberto@inf.puc-rio.br>	2019-07-24 15:01:59 -0300
commit	0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42 (patch)
tree	dcf79de5e0efc790142ed7e2fd418813c70d0c60
parent	7f5c31cdcac5388b3c48a26112dfb6d2cadb7321 (diff)
download	lua-0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42.tar.gz lua-0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42.tar.bz2 lua-0eb6aa4013051c8c0148c09d8c85ee7cbdc96f42.zip

diff --git a/loslib.c b/loslib.c index 8809e5ea..7812d29b 100644 --- a/loslib.c +++ b/loslib.c
@@ -58,18 +58,20 @@
58	** ===================================================================	58	** ===================================================================
59	*/	59	*/
60		60
61	#if !defined(l_time_t) /* { */
62	/*	61	/*
63	** type to represent time_t in Lua	62	** type to represent time_t in Lua
64	*/	63	*/
		64	#if !defined(LUA_NUMTIME) /* { */
		65
65	#define l_timet lua_Integer	66	#define l_timet lua_Integer
66	#define l_pushtime(L,t) lua_pushinteger(L,(lua_Integer)(t))	67	#define l_pushtime(L,t) lua_pushinteger(L,(lua_Integer)(t))
		68	#define l_gettime(L,arg) luaL_checkinteger(L, arg)
67		69
68	static time_t l_checktime (lua_State *L, int arg) {	70	#else /* }{ */
69	lua_Integer t = luaL_checkinteger(L, arg);	71
70	luaL_argcheck(L, (time_t)t == t, arg, "time out-of-bounds");	72	#define l_timet lua_Number
71	return (time_t)t;	73	#define l_pushtime(L,t) lua_pushnumber(L,(lua_Number)(t))
72	}	74	#define l_gettime(L,arg) luaL_checknumber(L, arg)
73		75
74	#endif /* } */	76	#endif /* } */
75		77
@@ -193,11 +195,25 @@ static int os_clock (lua_State *L) {
193	** =======================================================	195	** =======================================================
194	*/	196	*/
195		197
196	static void setfield (lua_State L, const char key, int value) {	198	/*
197	lua_pushinteger(L, value);	199	** About the overflow check: an overflow cannot occurr when time
		200	** is represented by a lua_Integer, because either lua_Integer is
		201	** large enough to represent all int fields or it is not large enough
		202	** to represent a time that cause a field to overflow. However, if
		203	** times are represented as doubles and lua_Integer is int, then the
		204	** time 0x1.e1853b0d184f6p+55 would cause an overflow when adding 1900
		205	** to compute the year.
		206	*/
		207	static void setfield (lua_State L, const char key, int value, int delta) {
		208	#if (defined(LUA_NUMTIME) && LUA_MAXINTEGER <= INT_MAX)
		209	if (value > LUA_MAXINTEGER - delta)
		210	luaL_error(L, "field '%s' is out-of-bound", key);
		211	#endif
		212	lua_pushinteger(L, (lua_Integer)value + delta);
198	lua_setfield(L, -2, key);	213	lua_setfield(L, -2, key);
199	}	214	}
200		215
		216
201	static void setboolfield (lua_State L, const char key, int value) {	217	static void setboolfield (lua_State L, const char key, int value) {
202	if (value < 0) /* undefined? */	218	if (value < 0) /* undefined? */
203	return; /* does not set field */	219	return; /* does not set field */
@@ -210,14 +226,14 @@ static void setboolfield (lua_State L, const char key, int value) {
210	** Set all fields from structure 'tm' in the table on top of the stack	226	** Set all fields from structure 'tm' in the table on top of the stack
211	*/	227	*/
212	static void setallfields (lua_State L, struct tm stm) {	228	static void setallfields (lua_State L, struct tm stm) {
213	setfield(L, "sec", stm->tm_sec);	229	setfield(L, "year", stm->tm_year, 1900);
214	setfield(L, "min", stm->tm_min);	230	setfield(L, "month", stm->tm_mon, 1);
215	setfield(L, "hour", stm->tm_hour);	231	setfield(L, "day", stm->tm_mday, 0);
216	setfield(L, "day", stm->tm_mday);	232	setfield(L, "hour", stm->tm_hour, 0);
217	setfield(L, "month", stm->tm_mon + 1);	233	setfield(L, "min", stm->tm_min, 0);
218	setfield(L, "year", stm->tm_year + 1900);	234	setfield(L, "sec", stm->tm_sec, 0);
219	setfield(L, "wday", stm->tm_wday + 1);	235	setfield(L, "yday", stm->tm_yday, 1);
220	setfield(L, "yday", stm->tm_yday + 1);	236	setfield(L, "wday", stm->tm_wday, 1);
221	setboolfield(L, "isdst", stm->tm_isdst);	237	setboolfield(L, "isdst", stm->tm_isdst);
222	}	238	}
223		239
@@ -230,11 +246,6 @@ static int getboolfield (lua_State L, const char key) {
230	}	246	}
231		247
232		248
233	/* maximum value for date fields (to avoid arithmetic overflows with 'int') */
234	#if !defined(L_MAXDATEFIELD)
235	#define L_MAXDATEFIELD (INT_MAX / 2)
236	#endif
237
238	static int getfield (lua_State L, const char key, int d, int delta) {	249	static int getfield (lua_State L, const char key, int d, int delta) {
239	int isnum;	250	int isnum;
240	int t = lua_getfield(L, -1, key); /* get field and its type */	251	int t = lua_getfield(L, -1, key); /* get field and its type */
@@ -247,7 +258,9 @@ static int getfield (lua_State L, const char key, int d, int delta) {
247	res = d;	258	res = d;
248	}	259	}
249	else {	260	else {
250	if (!(-L_MAXDATEFIELD <= res && res <= L_MAXDATEFIELD))	261	/* unsigned avoids overflow when lua_Integer has 32 bits */
		262	if (!(res >= 0 ? (lua_Unsigned)res <= (lua_Unsigned)INT_MAX + delta
		263	: (lua_Integer)INT_MIN + delta <= res))
251	return luaL_error(L, "field '%s' is out-of-bound", key);	264	return luaL_error(L, "field '%s' is out-of-bound", key);
252	res -= delta;	265	res -= delta;
253	}	266	}
@@ -275,6 +288,13 @@ static const char checkoption (lua_State L, const char *conv,
275	}	288	}
276		289
277		290
		291	static time_t l_checktime (lua_State *L, int arg) {
		292	l_timet t = l_gettime(L, arg);
		293	luaL_argcheck(L, (time_t)t == t, arg, "time out-of-bounds");
		294	return (time_t)t;
		295	}
		296
		297
278	/* maximum size for an individual 'strftime' item */	298	/* maximum size for an individual 'strftime' item */
279	#define SIZETIMEFMT 250	299	#define SIZETIMEFMT 250
280		300
@@ -293,7 +313,7 @@ static int os_date (lua_State *L) {
293	stm = l_localtime(&t, &tmr);	313	stm = l_localtime(&t, &tmr);
294	if (stm == NULL) /* invalid date? */	314	if (stm == NULL) /* invalid date? */
295	return luaL_error(L,	315	return luaL_error(L,
296	"time result cannot be represented in this installation");	316	"date result cannot be represented in this installation");
297	if (strcmp(s, "*t") == 0) {	317	if (strcmp(s, "*t") == 0) {
298	lua_createtable(L, 0, 9); /* 9 = number of fields */	318	lua_createtable(L, 0, 9); /* 9 = number of fields */
299	setallfields(L, stm);	319	setallfields(L, stm);
@@ -329,12 +349,12 @@ static int os_time (lua_State *L) {
329	struct tm ts;	349	struct tm ts;
330	luaL_checktype(L, 1, LUA_TTABLE);	350	luaL_checktype(L, 1, LUA_TTABLE);
331	lua_settop(L, 1); /* make sure table is at the top */	351	lua_settop(L, 1); /* make sure table is at the top */
332	ts.tm_sec = getfield(L, "sec", 0, 0);
333	ts.tm_min = getfield(L, "min", 0, 0);
334	ts.tm_hour = getfield(L, "hour", 12, 0);
335	ts.tm_mday = getfield(L, "day", -1, 0);
336	ts.tm_mon = getfield(L, "month", -1, 1);
337	ts.tm_year = getfield(L, "year", -1, 1900);	352	ts.tm_year = getfield(L, "year", -1, 1900);
		353	ts.tm_mon = getfield(L, "month", -1, 1);
		354	ts.tm_mday = getfield(L, "day", -1, 0);
		355	ts.tm_hour = getfield(L, "hour", 12, 0);
		356	ts.tm_min = getfield(L, "min", 0, 0);
		357	ts.tm_sec = getfield(L, "sec", 0, 0);
338	ts.tm_isdst = getboolfield(L, "isdst");	358	ts.tm_isdst = getboolfield(L, "isdst");
339	t = mktime(&ts);	359	t = mktime(&ts);
340	setallfields(L, &ts); /* update fields with normalized values */	360	setallfields(L, &ts); /* update fields with normalized values */


diff --git a/testes/files.lua b/testes/files.lua index c8f23d18..6e7bd9e2 100644 --- a/testes/files.lua +++ b/testes/files.lua
@@ -775,11 +775,24 @@ assert(os.date(string.rep("%d", 1000), t) ==
775	string.rep(os.date("%d", t), 1000))	775	string.rep(os.date("%d", t), 1000))
776	assert(os.date(string.rep("%", 200)) == string.rep("%", 100))	776	assert(os.date(string.rep("%", 200)) == string.rep("%", 100))
777		777
778	local t = os.time()	778	local function checkDateTable (t)
779	D = os.date("*t", t)	779	_G.D = os.date("*t", t)
780	load(os.date([[assert(D.year==%Y and D.month==%m and D.day==%d and	780	assert(os.time(D) == t)
781	D.hour==%H and D.min==%M and D.sec==%S and	781	load(os.date([[assert(D.year==%Y and D.month==%m and D.day==%d and
782	D.wday==%w+1 and D.yday==%j)]], t))()	782	D.hour==%H and D.min==%M and D.sec==%S and
		783	D.wday==%w+1 and D.yday==%j)]], t))()
		784	_G.D = nil
		785	end
		786
		787	checkDateTable(os.time())
		788	if not _port then
		789	-- assume that time_t can represent these values
		790	checkDateTable(0)
		791	checkDateTable(1)
		792	checkDateTable(1000)
		793	checkDateTable(0x7fffffff)
		794	checkDateTable(0x80000000)
		795	end
783		796
784	checkerr("invalid conversion specifier", os.date, "%")	797	checkerr("invalid conversion specifier", os.date, "%")
785	checkerr("invalid conversion specifier", os.date, "%9")	798	checkerr("invalid conversion specifier", os.date, "%9")
@@ -793,11 +806,24 @@ checkerr("not an integer", os.time, {year=1000, month=1, day=1, hour=1.5})
793		806
794	checkerr("missing", os.time, {hour = 12}) -- missing date	807	checkerr("missing", os.time, {hour = 12}) -- missing date
795		808
		809
		810	if string.packsize("i") == 4 then -- 4-byte ints
		811	checkerr("field 'year' is out-of-bound", os.time,
		812	{year = -(1 << 31) + 1899, month = 1, day = 1})
		813	end
		814
796	if not _port then	815	if not _port then
797	-- test Posix-specific modifiers	816	-- test Posix-specific modifiers
798	assert(type(os.date("%Ex")) == 'string')	817	assert(type(os.date("%Ex")) == 'string')
799	assert(type(os.date("%Oy")) == 'string')	818	assert(type(os.date("%Oy")) == 'string')
800		819
		820	-- test large dates (assume at least 4-byte ints and time_t)
		821	local t0 = os.time{year = 1970, month = 1, day = 0}
		822	local t1 = os.time{year = 1970, month = 1, day = 0, sec = (1 << 31) - 1}
		823	assert(t1 - t0 == (1 << 31) - 1)
		824	t0 = os.time{year = 1970, month = 1, day = 1}
		825	t1 = os.time{year = 1970, month = 1, day = 1, sec = -(1 << 31)}
		826	assert(t1 - t0 == -(1 << 31))
801		827
802	-- test out-of-range dates (at least for Unix)	828	-- test out-of-range dates (at least for Unix)
803	if maxint >= 2^62 then -- cannot do these tests in Small Lua	829	if maxint >= 2^62 then -- cannot do these tests in Small Lua
@@ -812,25 +838,37 @@ if not _port then
812	-- time_t has 8 bytes; an int year cannot represent a huge time	838	-- time_t has 8 bytes; an int year cannot represent a huge time
813	print(" 8-byte time_t")	839	print(" 8-byte time_t")
814	checkerr("cannot be represented", os.date, "%Y", 2^60)	840	checkerr("cannot be represented", os.date, "%Y", 2^60)
815	-- it should have no problems with year 4000	841
816	assert(tonumber(os.time{year=4000, month=1, day=1}))	842	-- this is the maximum year
		843	assert(tonumber(os.time
		844	{year=(1 << 31) + 1899, month=12, day=31, hour=23, min=59, sec=59}))
		845
		846	-- this is too much
		847	checkerr("represented", os.time,
		848	{year=(1 << 31) + 1899, month=12, day=31, hour=23, min=59, sec=60})
817	end	849	end
		850
		851	-- internal 'int' fields cannot hold these values
		852	checkerr("field 'day' is out-of-bound", os.time,
		853	{year = 0, month = 1, day = 2^32})
		854
		855	checkerr("field 'month' is out-of-bound", os.time,
		856	{year = 0, month = -((1 << 31) + 1), day = 1})
		857
		858	checkerr("field 'year' is out-of-bound", os.time,
		859	{year = (1 << 31) + 1900, month = 1, day = 1})
		860
818	else -- 8-byte ints	861	else -- 8-byte ints
819	-- assume time_t has 8 bytes too	862	-- assume time_t has 8 bytes too
820	print(" 8-byte time_t")	863	print(" 8-byte time_t")
821	assert(tonumber(os.date("%Y", 2^60)))	864	assert(tonumber(os.date("%Y", 2^60)))
		865
822	-- but still cannot represent a huge year	866	-- but still cannot represent a huge year
823	checkerr("cannot be represented", os.time, {year=2^60, month=1, day=1})	867	checkerr("cannot be represented", os.time, {year=2^60, month=1, day=1})
824	end	868	end
825	end	869	end
826	end	870	end
827		871
828
829	D = os.date("!*t", t)
830	load(os.date([[!assert(D.year==%Y and D.month==%m and D.day==%d and
831	D.hour==%H and D.min==%M and D.sec==%S and
832	D.wday==%w+1 and D.yday==%j)]], t))()
833
834	do	872	do
835	local D = os.date("*t")	873	local D = os.date("*t")
836	local t = os.time(D)	874	local t = os.time(D)
@@ -844,6 +882,7 @@ do
844	assert(t == t1) -- if isdst is absent uses correct default	882	assert(t == t1) -- if isdst is absent uses correct default
845	end	883	end
846		884
		885	local D = os.date("*t")
847	t = os.time(D)	886	t = os.time(D)
848	D.year = D.year-1;	887	D.year = D.year-1;
849	local t1 = os.time(D)	888	local t1 = os.time(D)