[interim-merge-commit] back-ported branch sebres-clock-speedup (from trunk to 8.6): tcl-clock functionality rewritten in C.

6 files changed, 2691 insertions, 685 deletions

diff --git a/generic/tclClock.c b/generic/tclClock.c
index a24b126..8e176b6 100644
--- a/generic/tclClock.c
+++ b/generic/tclClock.c
@@ -8,12 +8,15 @@
  * Copyright 1991-1995 Karl Lehenbauer and Mark Diekhans.
  * Copyright (c) 1995 Sun Microsystems, Inc.
  * Copyright (c) 2004 by Kevin B. Kenny. All rights reserved.
+ * Copyright (c) 2015 by Sergey G. Brester aka sebres. All rights reserved.
  *
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  */
 
 #include "tclInt.h"
+#include "tclStrIdxTree.h"
+#include "tclDate.h"
 
 /*
  * Windows has mktime. The configurators do not check.
@@ -24,21 +27,6 @@
 #endif
 
 /*
- * Constants
- */
-
-#define JULIAN_DAY_POSIX_EPOCH		2440588
-#define SECONDS_PER_DAY			86400
-#define JULIAN_SEC_POSIX_EPOCH	      (((Tcl_WideInt) JULIAN_DAY_POSIX_EPOCH) \
-					* SECONDS_PER_DAY)
-#define FOUR_CENTURIES			146097	/* days */
-#define JDAY_1_JAN_1_CE_JULIAN		1721424
-#define JDAY_1_JAN_1_CE_GREGORIAN	1721426
-#define ONE_CENTURY_GREGORIAN		36524	/* days */
-#define FOUR_YEARS			1461	/* days */
-#define ONE_YEAR			365	/* days */
-
-/*
  * Table of the days in each month, leap and common years
  */
 
@@ -55,70 +43,13 @@ static const int daysInPriorMonths[2][13] = {
  * Enumeration of the string literals used in [clock]
  */
 
-typedef enum ClockLiteral {
-    LIT__NIL,
-    LIT__DEFAULT_FORMAT,
-    LIT_BCE,		LIT_C,
-    LIT_CANNOT_USE_GMT_AND_TIMEZONE,
-    LIT_CE,
-    LIT_DAYOFMONTH,	LIT_DAYOFWEEK,		LIT_DAYOFYEAR,
-    LIT_ERA,		LIT_GMT,		LIT_GREGORIAN,
-    LIT_INTEGER_VALUE_TOO_LARGE,
-    LIT_ISO8601WEEK,	LIT_ISO8601YEAR,
-    LIT_JULIANDAY,	LIT_LOCALSECONDS,
-    LIT_MONTH,
-    LIT_SECONDS,	LIT_TZNAME,		LIT_TZOFFSET,
-    LIT_YEAR,
-    LIT__END
-} ClockLiteral;
-static const char *const literals[] = {
-    "",
-    "%a %b %d %H:%M:%S %Z %Y",
-    "BCE",		"C",
-    "cannot use -gmt and -timezone in same call",
-    "CE",
-    "dayOfMonth",	"dayOfWeek",		"dayOfYear",
-    "era",		":GMT",			"gregorian",
-    "integer value too large to represent",
-    "iso8601Week",	"iso8601Year",
-    "julianDay",	"localSeconds",
-    "month",
-    "seconds",		"tzName",		"tzOffset",
-    "year"
-};
-
-/*
- * Structure containing the client data for [clock]
- */
-
-typedef struct ClockClientData {
-    int refCount;		/* Number of live references. */
-    Tcl_Obj **literals;		/* Pool of object literals. */
-} ClockClientData;
+CLOCK_LITERAL_ARRAY(Literals);
 
-/*
- * Structure containing the fields used in [clock format] and [clock scan]
- */
+/* Msgcat literals for exact match (mcKey) */
+CLOCK_LOCALE_LITERAL_ARRAY(MsgCtLiterals, "");
+/* Msgcat index literals prefixed with _IDX_, used for quick dictionary search */
+CLOCK_LOCALE_LITERAL_ARRAY(MsgCtLitIdxs, "_IDX_");
 
-typedef struct TclDateFields {
-    Tcl_WideInt seconds;	/* Time expressed in seconds from the Posix
-				 * epoch */
-    Tcl_WideInt localSeconds;	/* Local time expressed in nominal seconds
-				 * from the Posix epoch */
-    int tzOffset;		/* Time zone offset in seconds east of
-				 * Greenwich */
-    Tcl_Obj *tzName;		/* Time zone name */
-    int julianDay;		/* Julian Day Number in local time zone */
-    enum {BCE=1, CE=0} era;	/* Era */
-    int gregorian;		/* Flag == 1 if the date is Gregorian */
-    int year;			/* Year of the era */
-    int dayOfYear;		/* Day of the year (1 January == 1) */
-    int month;			/* Month number */
-    int dayOfMonth;		/* Day of the month */
-    int iso8601Year;		/* ISO8601 week-based year */
-    int iso8601Week;		/* ISO8601 week number */
-    int dayOfWeek;		/* Day of the week */
-} TclDateFields;
 static const char *const eras[] = { "CE", "BCE", NULL };
 
 /*
@@ -139,26 +70,23 @@ TCL_DECLARE_MUTEX(clockMutex)
  * Function prototypes for local procedures in this file:
  */
 
-static int		ConvertUTCToLocal(Tcl_Interp *,
-			    TclDateFields *, Tcl_Obj *, int);
 static int		ConvertUTCToLocalUsingTable(Tcl_Interp *,
-			    TclDateFields *, int, Tcl_Obj *const[]);
+			    TclDateFields *, int, Tcl_Obj *const[],
+			    Tcl_WideInt rangesVal[2]);
 static int		ConvertUTCToLocalUsingC(Tcl_Interp *,
 			    TclDateFields *, int);
-static int		ConvertLocalToUTC(Tcl_Interp *,
-			    TclDateFields *, Tcl_Obj *, int);
+static int		ConvertLocalToUTC(ClientData clientData, Tcl_Interp *,
+			    TclDateFields *, Tcl_Obj *timezoneObj, int);
 static int		ConvertLocalToUTCUsingTable(Tcl_Interp *,
-			    TclDateFields *, int, Tcl_Obj *const[]);
+			    TclDateFields *, int, Tcl_Obj *const[],
+			    Tcl_WideInt rangesVal[2]);
 static int		ConvertLocalToUTCUsingC(Tcl_Interp *,
 			    TclDateFields *, int);
-static Tcl_Obj *	LookupLastTransition(Tcl_Interp *, Tcl_WideInt,
-			    int, Tcl_Obj *const *);
+static int		ClockConfigureObjCmd(ClientData clientData,
+			    Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]);
 static void		GetYearWeekDay(TclDateFields *, int);
 static void		GetGregorianEraYearDay(TclDateFields *, int);
 static void		GetMonthDay(TclDateFields *);
-static void		GetJulianDayFromEraYearWeekDay(TclDateFields *, int);
-static void		GetJulianDayFromEraYearMonthDay(TclDateFields *, int);
-static int		IsGregorianLeapYear(TclDateFields *);
 static int		WeekdayOnOrBefore(int, int);
 static int		ClockClicksObjCmd(
 			    ClientData clientData, Tcl_Interp *interp,
@@ -166,6 +94,10 @@ static int		ClockClicksObjCmd(
 static int		ClockConvertlocaltoutcObjCmd(
 			    ClientData clientData, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
+
+static int		ClockGetDateFields(ClientData clientData, 
+			    Tcl_Interp *interp, TclDateFields *fields, 
+			    Tcl_Obj *timezoneObj, int changeover);
 static int		ClockGetdatefieldsObjCmd(
 			    ClientData clientData, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
@@ -184,13 +116,28 @@ static int		ClockMicrosecondsObjCmd(
 static int		ClockMillisecondsObjCmd(
 			    ClientData clientData, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
-static int		ClockParseformatargsObjCmd(
+static int		ClockSecondsObjCmd(
 			    ClientData clientData, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
-static int		ClockSecondsObjCmd(
+static int		ClockFormatObjCmd(
+			    ClientData clientData, Tcl_Interp *interp,
+			    int objc, Tcl_Obj *const objv[]);
+static int		ClockScanObjCmd(
+			    ClientData clientData, Tcl_Interp *interp,
+			    int objc, Tcl_Obj *const objv[]);
+static int		ClockScanCommit(
+			    ClientData clientData, register DateInfo *info,
+			    register ClockFmtScnCmdArgs *opts);
+static int		ClockFreeScan(
+			    register DateInfo *info, 
+			    Tcl_Obj *strObj, ClockFmtScnCmdArgs *opts);
+static int		ClockCalcRelTime(
+			    register DateInfo *info, ClockFmtScnCmdArgs *opts);
+static int		ClockAddObjCmd(
 			    ClientData clientData, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
 static struct tm *	ThreadSafeLocalTime(const time_t *);
+static unsigned long	TzsetGetEpoch(void);
 static void		TzsetIfNecessary(void);
 static void		ClockDeleteCmdProc(ClientData);
 
@@ -209,6 +156,9 @@ struct ClockCommand {
 
 static const struct ClockCommand clockCommands[] = {
     { "getenv",			ClockGetenvObjCmd },
+    { "format",			ClockFormatObjCmd },
+    { "scan",			ClockScanObjCmd },
+    { "configure",		ClockConfigureObjCmd },
     { "Oldscan",		TclClockOldscanObjCmd },
     { "ConvertLocalToUTC",	ClockConvertlocaltoutcObjCmd },
     { "GetDateFields",		ClockGetdatefieldsObjCmd },
@@ -216,7 +166,6 @@ static const struct ClockCommand clockCommands[] = {
 		ClockGetjuliandayfromerayearmonthdayObjCmd },
     { "GetJulianDayFromEraYearWeekDay",
 		ClockGetjuliandayfromerayearweekdayObjCmd },
-    { "ParseFormatArgs",	ClockParseformatargsObjCmd },
     { NULL, NULL }
 };
 
@@ -279,9 +228,33 @@ TclClockInit(
     data->refCount = 0;
     data->literals = ckalloc(LIT__END * sizeof(Tcl_Obj*));
     for (i = 0; i < LIT__END; ++i) {
-	data->literals[i] = Tcl_NewStringObj(literals[i], -1);
-	Tcl_IncrRefCount(data->literals[i]);
+	Tcl_InitObjRef(data->literals[i], Tcl_NewStringObj(Literals[i], -1));
     }
+    data->mcLiterals = NULL;
+    data->mcLitIdxs = NULL;
+    data->LastTZEpoch = 0;
+    data->currentYearCentury = ClockDefaultYearCentury;
+    data->yearOfCenturySwitch = ClockDefaultCenturySwitch;
+    data->SystemTimeZone = NULL;
+    data->SystemSetupTZData = NULL;
+    data->GMTSetupTimeZone = NULL;
+    data->GMTSetupTZData = NULL;
+    data->AnySetupTimeZone = NULL;
+    data->AnySetupTZData = NULL;
+    data->LastUnnormSetupTimeZone = NULL;
+    data->LastSetupTimeZone = NULL;
+    data->LastSetupTZData = NULL;
+
+    data->CurrentLocale = NULL;
+    data->CurrentLocaleDict = NULL;
+    data->LastUnnormUsedLocale = NULL;
+    data->LastUsedLocale = NULL;
+    data->LastUsedLocaleDict = NULL;
+
+    data->lastBase.timezoneObj = NULL;
+    data->UTC2Local.timezoneObj = NULL;
+    data->UTC2Local.tzName = NULL;
+    data->Local2UTC.timezoneObj = NULL;
 
     /*
      * Install the commands.
@@ -305,17 +278,881 @@ TclClockInit(
 /*
  *----------------------------------------------------------------------
  *
+ * ClockConfigureClear --
+ *
+ *	Clean up cached resp. run-time storages used in clock commands.
+ *
+ *	Shared usage for clean-up (ClockDeleteCmdProc) and "configure -clear".
+ *
+ * Results:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+ClockConfigureClear(
+    ClockClientData *data)
+{
+    ClockFrmScnClearCaches();
+
+    data->LastTZEpoch = 0;
+    Tcl_UnsetObjRef(data->SystemTimeZone);
+    Tcl_UnsetObjRef(data->SystemSetupTZData);
+    Tcl_UnsetObjRef(data->GMTSetupTimeZone);
+    Tcl_UnsetObjRef(data->GMTSetupTZData);
+    Tcl_UnsetObjRef(data->AnySetupTimeZone);
+    Tcl_UnsetObjRef(data->AnySetupTZData);
+    Tcl_UnsetObjRef(data->LastUnnormSetupTimeZone);
+    Tcl_UnsetObjRef(data->LastSetupTimeZone);
+    Tcl_UnsetObjRef(data->LastSetupTZData);
+
+    Tcl_UnsetObjRef(data->CurrentLocale);
+    Tcl_UnsetObjRef(data->CurrentLocaleDict);
+    Tcl_UnsetObjRef(data->LastUnnormUsedLocale);
+    Tcl_UnsetObjRef(data->LastUsedLocale);
+    Tcl_UnsetObjRef(data->LastUsedLocaleDict);
+
+    Tcl_UnsetObjRef(data->lastBase.timezoneObj);
+    Tcl_UnsetObjRef(data->UTC2Local.timezoneObj);
+    Tcl_UnsetObjRef(data->UTC2Local.tzName);
+    Tcl_UnsetObjRef(data->Local2UTC.timezoneObj);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockDeleteCmdProc --
+ *
+ *	Remove a reference to the clock client data, and clean up memory
+ *	when it's all gone.
+ *
+ * Results:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+static void
+ClockDeleteCmdProc(
+    ClientData clientData)	/* Opaque pointer to the client data */
+{
+    ClockClientData *data = clientData;
+    int i;
+
+    if (data->refCount-- <= 1) {
+	for (i = 0; i < LIT__END; ++i) {
+	    Tcl_DecrRefCount(data->literals[i]);
+	}
+	if (data->mcLiterals != NULL) {
+	    for (i = 0; i < MCLIT__END; ++i) {
+		Tcl_DecrRefCount(data->mcLiterals[i]);
+	    }
+	    data->mcLiterals = NULL;
+	}
+	if (data->mcLitIdxs != NULL) {
+	    for (i = 0; i < MCLIT__END; ++i) {
+		Tcl_DecrRefCount(data->mcLitIdxs[i]);
+	    }
+	    data->mcLitIdxs = NULL;
+	}
+
+	ClockConfigureClear(data);
+
+	ckfree(data->literals);
+	ckfree(data);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * NormTimezoneObj --
+ *
+ *	Normalizes the timezone object (used for caching puposes).
+ *
+ *	If already cached time zone could be found, returns this
+ *	object (last setup or last used, system (current) or gmt).
+ *
+ * Results:
+ *	Normalized tcl object pointer.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static inline Tcl_Obj *
+NormTimezoneObj(
+    ClockClientData *dataPtr,  /* Client data containing literal pool */
+    Tcl_Obj *timezoneObj)
+{
+    const char *tz;
+    if ( timezoneObj == dataPtr->LastUnnormSetupTimeZone
+      && dataPtr->LastSetupTimeZone != NULL 
+    ) {
+	return dataPtr->LastSetupTimeZone;
+    }
+    if ( timezoneObj == dataPtr->LastSetupTimeZone
+      || timezoneObj == dataPtr->literals[LIT_GMT]
+      || timezoneObj == dataPtr->SystemTimeZone
+      || timezoneObj == dataPtr->AnySetupTimeZone
+    ) {
+	return timezoneObj;
+    }
+
+    tz = TclGetString(timezoneObj);
+    if (dataPtr->AnySetupTimeZone != NULL &&
+	(timezoneObj == dataPtr->AnySetupTimeZone
+	   || strcmp(tz, TclGetString(dataPtr->AnySetupTimeZone)) == 0
+	)
+    ) {
+	timezoneObj = dataPtr->AnySetupTimeZone;
+    }
+    else
+    if (dataPtr->SystemTimeZone != NULL &&
+	(timezoneObj == dataPtr->SystemTimeZone
+	   || strcmp(tz, TclGetString(dataPtr->SystemTimeZone)) == 0
+	)
+    ) {
+	timezoneObj = dataPtr->SystemTimeZone;
+    }
+    else
+    if (
+	strcmp(tz, Literals[LIT_GMT]) == 0
+    ) {
+	timezoneObj = dataPtr->literals[LIT_GMT];
+    }
+    return timezoneObj;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockGetSystemLocale --
+ *
+ *	Returns system locale.
+ *
+ *	Executes ::tcl::clock::GetSystemLocale in given interpreter.
+ *
+ * Results:
+ *	Returns system locale tcl object.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static inline Tcl_Obj *
+ClockGetSystemLocale(
+    ClockClientData *dataPtr,	/* Opaque pointer to literal pool, etc. */
+    Tcl_Interp *interp)		/* Tcl interpreter */
+{
+    if (Tcl_EvalObjv(interp, 1, &dataPtr->literals[LIT_GETSYSTEMLOCALE], 0) != TCL_OK) {
+	return NULL;
+    }
+
+    return Tcl_GetObjResult(interp);
+}
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockGetCurrentLocale --
+ *
+ *	Returns current locale.
+ *
+ *	Executes ::tcl::clock::mclocale in given interpreter.
+ *
+ * Results:
+ *	Returns current locale tcl object.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static inline Tcl_Obj *
+ClockGetCurrentLocale(
+    ClockClientData *dataPtr,	/* Client data containing literal pool */
+    Tcl_Interp *interp)		/* Tcl interpreter */
+{   
+    if (Tcl_EvalObjv(interp, 1, &dataPtr->literals[LIT_GETCURRENTLOCALE], 0) != TCL_OK) {
+	return NULL;
+    }
+
+    Tcl_SetObjRef(dataPtr->CurrentLocale, Tcl_GetObjResult(interp));
+    Tcl_UnsetObjRef(dataPtr->CurrentLocaleDict);
+
+    return dataPtr->CurrentLocale;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * NormLocaleObj --
+ *
+ *	Normalizes the locale object (used for caching puposes).
+ *
+ *	If already cached locale could be found, returns this
+ *	object (current, system (OS) or last used locales).
+ *
+ * Results:
+ *	Normalized tcl object pointer.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tcl_Obj *
+NormLocaleObj(
+    ClockClientData *dataPtr,	/* Client data containing literal pool */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    Tcl_Obj    *localeObj,
+    Tcl_Obj   **mcDictObj)
+{
+    const char *loc;
+    if ( localeObj == NULL || localeObj == dataPtr->CurrentLocale
+      || localeObj == dataPtr->literals[LIT_C] 
+      || localeObj == dataPtr->literals[LIT_CURRENT]
+    ) {
+	if (dataPtr->CurrentLocale == NULL) {
+	    ClockGetCurrentLocale(dataPtr, interp);
+	}
+	*mcDictObj = dataPtr->CurrentLocaleDict;
+	return dataPtr->CurrentLocale;
+    }
+    if ( localeObj == dataPtr->LastUsedLocale
+      || localeObj == dataPtr->LastUnnormUsedLocale
+    ) {
+	*mcDictObj = dataPtr->LastUsedLocaleDict;
+	return dataPtr->LastUsedLocale;
+    }
+
+    loc = TclGetString(localeObj);
+    if ( dataPtr->CurrentLocale != NULL
+      && ( localeObj == dataPtr->CurrentLocale
+       || (localeObj->length == dataPtr->CurrentLocale->length
+	  && strcmp(loc, TclGetString(dataPtr->CurrentLocale)) == 0
+	)
+      )
+    ) {
+	*mcDictObj = dataPtr->CurrentLocaleDict;
+	localeObj = dataPtr->CurrentLocale;
+    }
+    else
+    if ( dataPtr->LastUsedLocale != NULL
+      && ( localeObj == dataPtr->LastUsedLocale
+       || (localeObj->length == dataPtr->LastUsedLocale->length
+	  && strcmp(loc, TclGetString(dataPtr->LastUsedLocale)) == 0
+	)
+      )
+    ) {
+	*mcDictObj = dataPtr->LastUsedLocaleDict;
+	Tcl_SetObjRef(dataPtr->LastUnnormUsedLocale, localeObj);
+	localeObj = dataPtr->LastUsedLocale;
+    }
+    else
+    if (
+	 (localeObj->length == 1 /* C */
+	   && strncasecmp(loc, Literals[LIT_C], localeObj->length) == 0)
+      || (localeObj->length == 7 /* current */
+	   && strncasecmp(loc, Literals[LIT_CURRENT], localeObj->length) == 0)
+    ) {
+	if (dataPtr->CurrentLocale == NULL) {
+	    ClockGetCurrentLocale(dataPtr, interp);
+	}
+	*mcDictObj = dataPtr->CurrentLocaleDict;
+	localeObj = dataPtr->CurrentLocale;
+    } 
+    else 
+    if (
+	 (localeObj->length == 6 /* system */
+	   && strncasecmp(loc, Literals[LIT_SYSTEM], localeObj->length) == 0)
+    ) {
+	Tcl_SetObjRef(dataPtr->LastUnnormUsedLocale, localeObj);
+	localeObj = ClockGetSystemLocale(dataPtr, interp);
+	Tcl_SetObjRef(dataPtr->LastUsedLocale, localeObj);
+	*mcDictObj = NULL;
+    } 
+    else 
+    {
+	*mcDictObj = NULL;
+    }
+    return localeObj;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockMCDict --
+ *
+ *	Retrieves a localized storage dictionary object for the given 
+ *	locale object.
+ *
+ *	This corresponds with call `::tcl::clock::mcget locale`.
+ *	Cached representation stored in options (for further access).
+ *
+ * Results:
+ *	Tcl-object contains smart reference to msgcat dictionary.
+ *
+ *----------------------------------------------------------------------
+ */
+
+MODULE_SCOPE Tcl_Obj *
+ClockMCDict(ClockFmtScnCmdArgs *opts)
+{
+    ClockClientData *dataPtr = opts->clientData;
+
+    /* if dict not yet retrieved */
+    if (opts->mcDictObj == NULL) {
+
+	/* if locale was not yet used */
+	if ( !(opts->flags & CLF_LOCALE_USED) ) {
+	    
+	    opts->localeObj = NormLocaleObj(opts->clientData, opts->interp,
+		opts->localeObj, &opts->mcDictObj);
+	    
+	    if (opts->localeObj == NULL) {
+		Tcl_SetResult(opts->interp,
+		    "locale not specified and no default locale set", TCL_STATIC);
+		Tcl_SetErrorCode(opts->interp, "CLOCK", "badOption", NULL);
+		return NULL;
+	    }
+	    opts->flags |= CLF_LOCALE_USED;
+
+	    /* check locale literals already available (on demand creation) */
+	    if (dataPtr->mcLiterals == NULL) {
+		int i;
+		dataPtr->mcLiterals = ckalloc(MCLIT__END * sizeof(Tcl_Obj*));
+		for (i = 0; i < MCLIT__END; ++i) {
+		    Tcl_InitObjRef(dataPtr->mcLiterals[i], 
+			Tcl_NewStringObj(MsgCtLiterals[i], -1));
+		}
+	    }
+	}
+
+	if (opts->mcDictObj == NULL) {
+	    Tcl_Obj *callargs[2];
+	    /* get msgcat dictionary - ::tcl::clock::mcget locale */
+	    callargs[0] = dataPtr->literals[LIT_MCGET];
+	    callargs[1] = opts->localeObj;
+
+	    if (Tcl_EvalObjv(opts->interp, 2, callargs, 0) != TCL_OK) {
+		return NULL;
+	    }
+
+	    opts->mcDictObj = Tcl_GetObjResult(opts->interp);
+	    /* be sure that object reference not increases (dict changeable) */
+	    if (opts->mcDictObj->refCount > 0) {
+		/* smart reference (shared dict as object with no ref-counter) */
+		opts->mcDictObj = Tcl_DictObjSmartRef(opts->interp, opts->mcDictObj);
+	    }
+	    if ( opts->localeObj == dataPtr->CurrentLocale ) {
+		Tcl_SetObjRef(dataPtr->CurrentLocaleDict, opts->mcDictObj);
+	    } else if ( opts->localeObj == dataPtr->LastUsedLocale ) {
+		Tcl_SetObjRef(dataPtr->LastUsedLocaleDict, opts->mcDictObj);
+	    } else {
+		Tcl_SetObjRef(dataPtr->LastUsedLocale, opts->localeObj);
+		Tcl_UnsetObjRef(dataPtr->LastUnnormUsedLocale);
+		Tcl_SetObjRef(dataPtr->LastUsedLocaleDict, opts->mcDictObj);
+	    }
+	    Tcl_ResetResult(opts->interp);
+	}
+    }
+
+    return opts->mcDictObj;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockMCGet --
+ *
+ *	Retrieves a msgcat value for the given literal integer mcKey
+ *	from localized storage (corresponding given locale object)
+ *	by mcLiterals[mcKey] (e. g. MONTHS_FULL).
+ *
+ * Results:
+ *	Tcl-object contains localized value.
+ *
+ *----------------------------------------------------------------------
+ */
+
+MODULE_SCOPE Tcl_Obj *
+ClockMCGet(
+    ClockFmtScnCmdArgs *opts, 
+    int mcKey)
+{
+    ClockClientData *dataPtr = opts->clientData;
+
+    Tcl_Obj *valObj = NULL;
+
+    if (opts->mcDictObj == NULL) {
+	ClockMCDict(opts);
+	if (opts->mcDictObj == NULL)
+	    return NULL;
+    }
+
+    Tcl_DictObjGet(opts->interp, opts->mcDictObj, 
+	dataPtr->mcLiterals[mcKey], &valObj);
+
+    return valObj; /* or NULL in obscure case if Tcl_DictObjGet failed */
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockMCGetIdx --
+ *
+ *	Retrieves an indexed msgcat value for the given literal integer mcKey
+ *	from localized storage (corresponding given locale object)
+ *	by mcLitIdxs[mcKey] (e. g. _IDX_MONTHS_FULL).
+ *
+ * Results:
+ *	Tcl-object contains localized indexed value.
+ *
+ *----------------------------------------------------------------------
+ */
+
+MODULE_SCOPE Tcl_Obj *
+ClockMCGetIdx(
+    ClockFmtScnCmdArgs *opts, 
+    int mcKey)
+{
+    ClockClientData *dataPtr = opts->clientData;
+
+    Tcl_Obj *valObj = NULL;
+
+    if (opts->mcDictObj == NULL) {
+	ClockMCDict(opts);
+	if (opts->mcDictObj == NULL)
+	    return NULL;
+    }
+
+    /* try to get indices object */
+    if (dataPtr->mcLitIdxs == NULL) {
+	return NULL;
+    }
+    
+    if (Tcl_DictObjGet(NULL, opts->mcDictObj, 
+	dataPtr->mcLitIdxs[mcKey], &valObj) != TCL_OK
+    ) {
+	return NULL;
+    }
+
+    return valObj;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockMCSetIdx --
+ *
+ *	Sets an indexed msgcat value for the given literal integer mcKey
+ *	in localized storage (corresponding given locale object)
+ *	by mcLitIdxs[mcKey] (e. g. _IDX_MONTHS_FULL).
+ *
+ * Results:
+ *	Returns a standard Tcl result.
+ *
+ *----------------------------------------------------------------------
+ */
+
+MODULE_SCOPE int
+ClockMCSetIdx(
+    ClockFmtScnCmdArgs *opts, 
+    int mcKey, Tcl_Obj *valObj)
+{
+    ClockClientData *dataPtr = opts->clientData;
+
+    if (opts->mcDictObj == NULL) {
+	ClockMCDict(opts);
+	if (opts->mcDictObj == NULL)
+	    return TCL_ERROR;
+    }
+
+    /* if literal storage for indices not yet created */
+    if (dataPtr->mcLitIdxs == NULL) {
+	int i;
+	dataPtr->mcLitIdxs = ckalloc(MCLIT__END * sizeof(Tcl_Obj*));
+	for (i = 0; i < MCLIT__END; ++i) {
+	    Tcl_InitObjRef(dataPtr->mcLitIdxs[i], 
+		Tcl_NewStringObj(MsgCtLitIdxs[i], -1));
+	}
+    }
+
+    return Tcl_DictObjPut(opts->interp, opts->mcDictObj, 
+	    dataPtr->mcLitIdxs[mcKey], valObj);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockConfigureObjCmd --
+ *
+ *	This function is invoked to process the Tcl "clock configure" command.
+ *
+ * Usage:
+ *	::tcl::clock::configure ?-option ?value??
+ *
+ * Results:
+ *	Returns a standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+ClockConfigureObjCmd(
+    ClientData clientData,  /* Client data containing literal pool */
+    Tcl_Interp *interp,	    /* Tcl interpreter */
+    int objc,		    /* Parameter count */
+    Tcl_Obj *const objv[])  /* Parameter vector */
+{
+    ClockClientData *dataPtr = clientData;
+    
+    static const char *const options[] = {
+	"-system-tz",	  "-setup-tz",	  "-default-locale",
+	"-clear",
+	"-year-century",  "-century-switch",
+	NULL
+    };
+    enum optionInd {
+	CLOCK_SYSTEM_TZ,  CLOCK_SETUP_TZ, CLOCK_CURRENT_LOCALE,
+	CLOCK_CLEAR_CACHE,
+	CLOCK_YEAR_CENTURY, CLOCK_CENTURY_SWITCH,
+	CLOCK_SETUP_GMT, CLOCK_SETUP_NOP
+    };
+    int optionIndex;		/* Index of an option. */
+    int i;
+
+    for (i = 1; i < objc; i++) {
+	if (Tcl_GetIndexFromObj(interp, objv[i++], options, 
+	    "option", 0, &optionIndex) != TCL_OK) {
+	    Tcl_SetErrorCode(interp, "CLOCK", "badOption",
+		    Tcl_GetString(objv[i-1]), NULL);
+	    return TCL_ERROR;
+	}
+	switch (optionIndex) {
+	case CLOCK_SYSTEM_TZ:
+	if (1) {
+	    /* validate current tz-epoch */
+	    unsigned long lastTZEpoch = TzsetGetEpoch();
+	    if (i < objc) {
+		if (dataPtr->SystemTimeZone != objv[i]) {
+		    Tcl_SetObjRef(dataPtr->SystemTimeZone, objv[i]);
+		    Tcl_UnsetObjRef(dataPtr->SystemSetupTZData);
+		}
+		dataPtr->LastTZEpoch = lastTZEpoch;
+	    } 
+	    if (i+1 >= objc && dataPtr->SystemTimeZone != NULL 
+			 && dataPtr->LastTZEpoch == lastTZEpoch) {
+		Tcl_SetObjResult(interp, dataPtr->SystemTimeZone);
+	    }
+	}
+	break;
+	case CLOCK_SETUP_TZ:
+	    if (i < objc) {
+		/* differentiate GMT and system zones, because used often */
+		Tcl_Obj *timezoneObj = NormTimezoneObj(dataPtr, objv[i]);
+		Tcl_SetObjRef(dataPtr->LastUnnormSetupTimeZone, objv[i]);
+		if (dataPtr->LastSetupTimeZone != timezoneObj) {
+		    Tcl_SetObjRef(dataPtr->LastSetupTimeZone, timezoneObj);
+		    Tcl_UnsetObjRef(dataPtr->LastSetupTZData);
+		}
+		if (timezoneObj == dataPtr->literals[LIT_GMT]) {
+		    optionIndex = CLOCK_SETUP_GMT;
+		} else if (timezoneObj == dataPtr->SystemTimeZone) {
+		    optionIndex = CLOCK_SETUP_NOP;
+		}
+		switch (optionIndex) {
+		case CLOCK_SETUP_GMT:
+		    if (i < objc) {
+			if (dataPtr->GMTSetupTimeZone != timezoneObj) {
+			    Tcl_SetObjRef(dataPtr->GMTSetupTimeZone, timezoneObj);
+			    Tcl_UnsetObjRef(dataPtr->GMTSetupTZData);
+			}
+		    }
+		break;
+		case CLOCK_SETUP_TZ:
+		    if (i < objc) {
+			if (dataPtr->AnySetupTimeZone != timezoneObj) {
+			    Tcl_SetObjRef(dataPtr->AnySetupTimeZone, timezoneObj);
+			    Tcl_UnsetObjRef(dataPtr->AnySetupTZData);
+			}
+		    } 
+		break;
+		}
+	    }
+	    if (i+1 >= objc && dataPtr->LastSetupTimeZone != NULL) {
+		Tcl_SetObjResult(interp, dataPtr->LastSetupTimeZone);
+	    }
+	break;
+	case CLOCK_CURRENT_LOCALE:
+	    if (i < objc) {
+		if (dataPtr->CurrentLocale != objv[i]) {
+		    Tcl_SetObjRef(dataPtr->CurrentLocale, objv[i]);
+		    Tcl_UnsetObjRef(dataPtr->CurrentLocaleDict);
+		}
+	    }
+	    if (i+1 >= objc && dataPtr->CurrentLocale != NULL) {
+		Tcl_SetObjResult(interp, dataPtr->CurrentLocale);
+	    }
+	break;
+	case CLOCK_YEAR_CENTURY:
+	    if (i < objc) {
+		int year;
+		if (TclGetIntFromObj(interp, objv[i], &year) != TCL_OK) {
+		    return TCL_ERROR;
+		}
+		dataPtr->currentYearCentury = year;
+		if (i+1 >= objc) {
+		    Tcl_SetObjResult(interp, objv[i]);
+		}
+		continue;
+	    }
+	    if (i+1 >= objc) {
+		Tcl_SetObjResult(interp, 
+		    Tcl_NewIntObj(dataPtr->currentYearCentury));
+	    }
+	break;
+	case CLOCK_CENTURY_SWITCH:
+	    if (i < objc) {
+		int year;
+		if (TclGetIntFromObj(interp, objv[i], &year) != TCL_OK) {
+		    return TCL_ERROR;
+		}
+		dataPtr->yearOfCenturySwitch = year;
+		Tcl_SetObjResult(interp, objv[i]);
+		continue;
+	    }
+	    if (i+1 >= objc) {
+		Tcl_SetObjResult(interp, 
+		    Tcl_NewIntObj(dataPtr->yearOfCenturySwitch));
+	    }
+	break;
+	case CLOCK_CLEAR_CACHE:
+	    ClockConfigureClear(dataPtr);
+	break;
+	}
+    }
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockGetTZData --
+ *
+ *	Retrieves tzdata table for given normalized timezone.
+ *
+ * Results:
+ *	Returns a tcl object with tzdata.
+ *
+ * Side effects:
+ *	The tzdata can be cached in ClockClientData structure.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static inline Tcl_Obj *
+ClockGetTZData(
+    ClientData clientData,	/* Opaque pointer to literal pool, etc. */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    Tcl_Obj *timezoneObj)	/* Name of the timezone */
+{
+    ClockClientData *dataPtr = clientData;
+    Tcl_Obj **literals = dataPtr->literals;
+    Tcl_Obj *ret, **out = NULL;
+
+    /* if cached (if already setup this one) */
+    if ( dataPtr->LastSetupTZData != NULL
+      && ( timezoneObj == dataPtr->LastSetupTimeZone
+	|| timezoneObj == dataPtr->LastUnnormSetupTimeZone
+      )
+    ) {
+	return dataPtr->LastSetupTZData;
+    }
+
+    /* differentiate GMT and system zones, because used often */
+    /* simple caching, because almost used the tz-data of last timezone
+     */
+    if (timezoneObj == dataPtr->SystemTimeZone) {
+	if (dataPtr->SystemSetupTZData != NULL) {
+	    return dataPtr->SystemSetupTZData;
+	}
+	out = &dataPtr->SystemSetupTZData;
+    }
+    else 
+    if (timezoneObj == dataPtr->GMTSetupTimeZone) {
+	if (dataPtr->GMTSetupTZData != NULL) {
+	    return dataPtr->GMTSetupTZData;
+	}
+	out = &dataPtr->GMTSetupTZData;
+    }
+    else
+    if (timezoneObj == dataPtr->AnySetupTimeZone) {
+	if (dataPtr->AnySetupTZData != NULL) {
+	    return dataPtr->AnySetupTZData;
+	}
+	out = &dataPtr->AnySetupTZData;
+    }
+
+    ret = Tcl_ObjGetVar2(interp, literals[LIT_TZDATA],
+	timezoneObj, TCL_LEAVE_ERR_MSG);
+
+    /* cache using corresponding slot and as last used */
+    if (out != NULL) {
+	Tcl_SetObjRef(*out, ret);
+    }
+    Tcl_SetObjRef(dataPtr->LastSetupTZData, ret);
+    if (dataPtr->LastSetupTimeZone != timezoneObj) {
+	Tcl_SetObjRef(dataPtr->LastSetupTimeZone, timezoneObj);
+	Tcl_UnsetObjRef(dataPtr->LastUnnormSetupTimeZone);
+    }
+    return ret;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockGetSystemTimeZone --
+ *
+ *	Returns system (current) timezone.
+ *
+ *	If system zone not yet cached, it executes ::tcl::clock::GetSystemTimeZone
+ *	in given interpreter and caches its result.
+ *
+ * Results:
+ *	Returns normalized timezone object.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tcl_Obj *
+ClockGetSystemTimeZone(
+    ClientData clientData,	/* Opaque pointer to literal pool, etc. */
+    Tcl_Interp *interp)		/* Tcl interpreter */
+{
+    ClockClientData *dataPtr = clientData;
+    Tcl_Obj **literals;
+
+    /* if known (cached and same epoch) - return now */
+    if (dataPtr->SystemTimeZone != NULL 
+	  && dataPtr->LastTZEpoch == TzsetGetEpoch()) {
+	return dataPtr->SystemTimeZone;
+    }
+
+    Tcl_UnsetObjRef(dataPtr->SystemTimeZone);
+    Tcl_UnsetObjRef(dataPtr->SystemSetupTZData);
+
+    literals = dataPtr->literals;
+
+    if (Tcl_EvalObjv(interp, 1, &literals[LIT_GETSYSTEMTIMEZONE], 0) != TCL_OK) {
+	return NULL;
+    }
+    if (dataPtr->SystemTimeZone == NULL) {
+	Tcl_SetObjRef(dataPtr->SystemTimeZone, Tcl_GetObjResult(interp));
+    }
+    return dataPtr->SystemTimeZone;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockSetupTimeZone --
+ *
+ *	Sets up the timezone. Loads tzdata, etc.
+ *
+ * Results:
+ *	Returns normalized timezone object.
+ *
+ *----------------------------------------------------------------------
+ */
+
+MODULE_SCOPE Tcl_Obj *
+ClockSetupTimeZone(
+    ClientData clientData,	/* Opaque pointer to literal pool, etc. */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    Tcl_Obj *timezoneObj)
+{
+    ClockClientData *dataPtr = clientData;
+    Tcl_Obj **literals = dataPtr->literals;
+    Tcl_Obj *callargs[2];
+
+    /* if cached (if already setup this one) */
+    if ( dataPtr->LastSetupTimeZone != NULL
+      && ( timezoneObj == dataPtr->LastSetupTimeZone
+	|| timezoneObj == dataPtr->LastUnnormSetupTimeZone
+      )
+    ) {
+	return dataPtr->LastSetupTimeZone;
+    }
+
+    /* differentiate GMT and system zones, because used often and already set */
+    timezoneObj = NormTimezoneObj(dataPtr, timezoneObj);
+    if (   timezoneObj == dataPtr->GMTSetupTimeZone
+	|| timezoneObj == dataPtr->SystemTimeZone
+	|| timezoneObj == dataPtr->AnySetupTimeZone
+    ) {
+	return timezoneObj;
+    }
+
+    callargs[0] = literals[LIT_SETUPTIMEZONE];
+    callargs[1] = timezoneObj;
+
+    if (Tcl_EvalObjv(interp, 2, callargs, 0) == TCL_OK) {
+	return dataPtr->LastSetupTimeZone;
+    }
+    return NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ClockFormatNumericTimeZone --
+ *
+ *	Formats a time zone as +hhmmss
+ *
+ * Parameters:
+ *	z - Time zone in seconds east of Greenwich
+ *
+ * Results:
+ *	Returns the time zone object (formatted in a numeric form)
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Obj * 
+ClockFormatNumericTimeZone(int z) {
+    char sign = '+';
+    int h, m;
+    if ( z < 0 ) {
+	z = -z;
+	sign = '-';
+    }
+    h = z / 3600;
+    z %= 3600;
+    m = z / 60;
+    z %= 60;
+    if (z != 0) {
+	return Tcl_ObjPrintf("%c%02d%02d%02d", sign, h, m, z);
+    }
+    return Tcl_ObjPrintf("%c%02d%02d", sign, h, m);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * ClockConvertlocaltoutcObjCmd --
  *
  *	Tcl command that converts a UTC time to a local time by whatever means
  *	is available.
  *
  * Usage:
- *	::tcl::clock::ConvertUTCToLocal dictionary tzdata changeover
+ *	::tcl::clock::ConvertUTCToLocal dictionary timezone changeover
  *
  * Parameters:
  *	dict - Dictionary containing a 'localSeconds' entry.
- *	tzdata - Time zone data
+ *	timezone - Time zone
  *	changeover - Julian Day of the adoption of the Gregorian calendar.
  *
  * Results:
@@ -345,12 +1182,13 @@ ClockConvertlocaltoutcObjCmd(
     int created = 0;
     int status;
 
+    fields.tzName = NULL;
     /*
      * Check params and convert time.
      */
 
     if (objc != 4) {
-	Tcl_WrongNumArgs(interp, 1, objv, "dict tzdata changeover");
+	Tcl_WrongNumArgs(interp, 1, objv, "dict timezone changeover");
 	return TCL_ERROR;
     }
     dict = objv[1];
@@ -363,10 +1201,10 @@ ClockConvertlocaltoutcObjCmd(
 		"found in dictionary", -1));
 	return TCL_ERROR;
     }
-    if ((Tcl_GetWideIntFromObj(interp, secondsObj,
+    if ((TclGetWideIntFromObj(interp, secondsObj,
 	    &fields.localSeconds) != TCL_OK)
 	|| (TclGetIntFromObj(interp, objv[3], &changeover) != TCL_OK)
-	|| ConvertLocalToUTC(interp, &fields, objv[2], changeover)) {
+	|| ConvertLocalToUTC(clientData, interp, &fields, objv[2], changeover)) {
 	return TCL_ERROR;
     }
 
@@ -400,12 +1238,11 @@ ClockConvertlocaltoutcObjCmd(
  *	formatting a date, and populates a dictionary with them.
  *
  * Usage:
- *	::tcl::clock::GetDateFields seconds tzdata changeover
+ *	::tcl::clock::GetDateFields seconds timezone changeover
  *
  * Parameters:
  *	seconds - Time expressed in seconds from the Posix epoch.
- *	tzdata - Time zone data of the time zone in which time is to be
- *		 expressed.
+ *	timezone - Time zone in which time is to be expressed.
  *	changeover - Julian Day Number at which the current locale adopted
  *		     the Gregorian calendar
  *
@@ -434,15 +1271,17 @@ ClockGetdatefieldsObjCmd(
     Tcl_Obj *const *literals = data->literals;
     int changeover;
 
+    fields.tzName = NULL;
+
     /*
      * Check params.
      */
 
     if (objc != 4) {
-	Tcl_WrongNumArgs(interp, 1, objv, "seconds tzdata changeover");
+	Tcl_WrongNumArgs(interp, 1, objv, "seconds timezone changeover");
 	return TCL_ERROR;
     }
-    if (Tcl_GetWideIntFromObj(interp, objv[1], &fields.seconds) != TCL_OK
+    if (TclGetWideIntFromObj(interp, objv[1], &fields.seconds) != TCL_OK
 	    || TclGetIntFromObj(interp, objv[3], &changeover) != TCL_OK) {
 	return TCL_ERROR;
     }
@@ -457,28 +1296,14 @@ ClockGetdatefieldsObjCmd(
 	return TCL_ERROR;
     }
 
-    /*
-     * Convert UTC time to local.
-     */
+    /* Extract fields */
 
-    if (ConvertUTCToLocal(interp, &fields, objv[2], changeover) != TCL_OK) {
+    if (ClockGetDateFields(clientData, interp, &fields, objv[2], 
+	  changeover) != TCL_OK) {
 	return TCL_ERROR;
     }
 
-    /*
-     * Extract Julian day.
-     */
-
-    fields.julianDay = (int) ((fields.localSeconds + JULIAN_SEC_POSIX_EPOCH)
-	    / SECONDS_PER_DAY);
-
-    /*
-     * Convert to Julian or Gregorian calendar.
-     */
-
-    GetGregorianEraYearDay(&fields, changeover);
-    GetMonthDay(&fields);
-    GetYearWeekDay(&fields, changeover);
+    /* Make dict of fields */
 
     dict = Tcl_NewDictObj();
     Tcl_DictObjPut(NULL, dict, literals[LIT_LOCALSECONDS],
@@ -517,6 +1342,58 @@ ClockGetdatefieldsObjCmd(
 /*
  *----------------------------------------------------------------------
  *
+ * ClockGetDateFields --
+ *
+ *	Converts given UTC time (seconds in a TclDateFields structure) 
+ *	to local time and determines the values that clock routines will 
+ *	use in scanning or formatting a date.
+ *
+ * Results:
+ *	Date-time values are stored in structure "fields".
+ *	Returns a standard Tcl result.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+ClockGetDateFields(
+    ClientData clientData,	/* Client data of the interpreter */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    TclDateFields *fields,	/* Pointer to result fields, where
+				 * fields->seconds contains date to extract */
+    Tcl_Obj *timezoneObj,	/* Time zone object or NULL for gmt */
+    int changeover)		/* Julian Day Number */
+{
+    /*
+     * Convert UTC time to local.
+     */
+
+    if (ConvertUTCToLocal(clientData, interp, fields, timezoneObj,
+	    changeover) != TCL_OK) {
+	return TCL_ERROR;
+    }
+
+    /*
+     * Extract Julian day.
+     */
+
+    fields->julianDay = (int) ((fields->localSeconds + JULIAN_SEC_POSIX_EPOCH)
+	    / SECONDS_PER_DAY);
+
+    /*
+     * Convert to Julian or Gregorian calendar.
+     */
+
+    GetGregorianEraYearDay(fields, changeover);
+    GetMonthDay(fields);
+    GetYearWeekDay(fields, changeover);
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * ClockGetjuliandayfromerayearmonthdayObjCmd --
  *
  *	Tcl command that converts a time from era-year-month-day to a Julian
@@ -591,6 +1468,8 @@ ClockGetjuliandayfromerayearmonthdayObjCmd(
     int status;
     int era = 0;
 
+    fields.tzName = NULL;
+
     /*
      * Check params.
      */
@@ -675,6 +1554,8 @@ ClockGetjuliandayfromerayearweekdayObjCmd(
     int status;
     int era = 0;
 
+    fields.tzName = NULL;
+
     /*
      * Check params.
      */
@@ -742,18 +1623,70 @@ ClockGetjuliandayfromerayearweekdayObjCmd(
 
 static int
 ConvertLocalToUTC(
+    ClientData clientData,	/* Client data of the interpreter */
     Tcl_Interp *interp,		/* Tcl interpreter */
     TclDateFields *fields,	/* Fields of the time */
-    Tcl_Obj *tzdata,		/* Time zone data */
+    Tcl_Obj *timezoneObj,	/* Time zone */
     int changeover)		/* Julian Day of the Gregorian transition */
 {
+    ClockClientData *dataPtr = clientData;
+    Tcl_Obj *tzdata;		/* Time zone data */
     int rowc;			/* Number of rows in tzdata */
     Tcl_Obj **rowv;		/* Pointers to the rows */
+    Tcl_WideInt seconds;
+
+    /* fast phase-out for shared GMT-object (don't need to convert UTC 2 UTC) */
+    if (timezoneObj == dataPtr->GMTSetupTimeZone && dataPtr->GMTSetupTimeZone != NULL) {
+	fields->seconds = fields->localSeconds;
+	fields->tzOffset = 0;
+	return TCL_OK;
+    }
+
+    /*
+     * Check cacheable conversion could be used
+     * (last-period Local2UTC cache within the same TZ)
+     */
+    seconds = fields->localSeconds - dataPtr->Local2UTC.tzOffset;
+    if ( timezoneObj == dataPtr->Local2UTC.timezoneObj
+      && ( fields->localSeconds == dataPtr->Local2UTC.localSeconds
+	|| ( seconds >= dataPtr->Local2UTC.rangesVal[0]
+	  && seconds <	dataPtr->Local2UTC.rangesVal[1])
+      )
+      && changeover == dataPtr->Local2UTC.changeover
+    ) {
+	/* the same time zone and offset (UTC time inside the last minute) */
+	fields->tzOffset = dataPtr->Local2UTC.tzOffset;
+	fields->seconds = seconds;
+	return TCL_OK;
+    }
+
+    /*
+     * Check cacheable back-conversion could be used
+     * (last-period UTC2Local cache within the same TZ)
+     */
+    seconds = fields->localSeconds - dataPtr->UTC2Local.tzOffset;
+    if ( timezoneObj == dataPtr->UTC2Local.timezoneObj
+      && ( seconds == dataPtr->UTC2Local.seconds
+	|| ( seconds >= dataPtr->UTC2Local.rangesVal[0]
+	  && seconds <	dataPtr->UTC2Local.rangesVal[1])
+      )
+      && changeover == dataPtr->UTC2Local.changeover
+    ) {
+	/* the same time zone and offset (UTC time inside the last minute) */
+	fields->tzOffset = dataPtr->UTC2Local.tzOffset;
+	fields->seconds = seconds;
+	return TCL_OK;
+    }
 
     /*
      * Unpack the tz data.
      */
 
+    tzdata = ClockGetTZData(clientData, interp, timezoneObj);
+    if (tzdata == NULL) {
+	return TCL_ERROR;
+    }
+
     if (TclListObjGetElements(interp, tzdata, &rowc, &rowv) != TCL_OK) {
 	return TCL_ERROR;
     }
@@ -764,10 +1697,26 @@ ConvertLocalToUTC(
      */
 
     if (rowc == 0) {
-	return ConvertLocalToUTCUsingC(interp, fields, changeover);
+	dataPtr->Local2UTC.rangesVal[0] = 0;
+	dataPtr->Local2UTC.rangesVal[1] = 0;
+
+	if (ConvertLocalToUTCUsingC(interp, fields, changeover) != TCL_OK) {
+	    return TCL_ERROR;
+	};
     } else {
-	return ConvertLocalToUTCUsingTable(interp, fields, rowc, rowv);
+	if (ConvertLocalToUTCUsingTable(interp, fields, rowc, rowv, 
+		dataPtr->Local2UTC.rangesVal) != TCL_OK) {
+	    return TCL_ERROR;
+	};
     }
+
+    /* Cache the last conversion */
+    Tcl_SetObjRef(dataPtr->Local2UTC.timezoneObj, timezoneObj);
+    dataPtr->Local2UTC.localSeconds = fields->localSeconds;
+    dataPtr->Local2UTC.changeover = changeover;
+    dataPtr->Local2UTC.tzOffset = fields->tzOffset;
+
+    return TCL_OK;
 }
 
 /*
@@ -793,7 +1742,8 @@ ConvertLocalToUTCUsingTable(
     Tcl_Interp *interp,		/* Tcl interpreter */
     TclDateFields *fields,	/* Time to convert, with 'seconds' filled in */
     int rowc,			/* Number of points at which time changes */
-    Tcl_Obj *const rowv[])	/* Points at which time changes */
+    Tcl_Obj *const rowv[],	/* Points at which time changes */
+    Tcl_WideInt rangesVal[2])	/* Return bounds for time period */
 {
     Tcl_Obj *row;
     int cellc;
@@ -817,7 +1767,8 @@ ConvertLocalToUTCUsingTable(
     fields->tzOffset = 0;
     fields->seconds = fields->localSeconds;
     while (!found) {
-	row = LookupLastTransition(interp, fields->seconds, rowc, rowv);
+	row = LookupLastTransition(interp, fields->seconds, rowc, rowv,
+		    rangesVal);
 	if ((row == NULL)
 		|| TclListObjGetElements(interp, row, &cellc,
 		    &cellv) != TCL_OK
@@ -842,6 +1793,41 @@ ConvertLocalToUTCUsingTable(
     }
     fields->tzOffset = have[i];
     fields->seconds = fields->localSeconds - fields->tzOffset;
+
+#if 0
+    /* currently unused, test purposes only */
+    /*
+     * Convert back from UTC, if local times are different - wrong local time
+     * (local time seems to be in between DST-hole).
+     */
+    if (fields->tzOffset) {
+
+	int corrOffset;
+	Tcl_WideInt backCompVal;
+	/* check DST-hole interval contains UTC time */
+	TclGetWideIntFromObj(NULL, cellv[0], &backCompVal);
+	if ( fields->seconds >= backCompVal - fields->tzOffset 
+	  && fields->seconds <= backCompVal + fields->tzOffset
+	) {
+	    row = LookupLastTransition(interp, fields->seconds, rowc, rowv);
+	    if (row == NULL ||
+		    TclListObjGetElements(interp, row, &cellc, &cellv) != TCL_OK ||
+		    TclGetIntFromObj(interp, cellv[1], &corrOffset) != TCL_OK) {
+		return TCL_ERROR;
+	    }
+	    if (fields->localSeconds != fields->seconds + corrOffset) {
+		Tcl_Panic("wrong local time %ld by LocalToUTC conversion,"
+		    " local time seems to be in between DST-hole", 
+		    fields->localSeconds);
+		/* correcting offset * /
+		fields->tzOffset -= corrOffset;
+		fields->seconds += fields->tzOffset;
+		*/
+	    }
+	}
+    }
+#endif
+
     return TCL_OK;
 }
 
@@ -943,20 +1929,61 @@ ConvertLocalToUTCUsingC(
  *----------------------------------------------------------------------
  */
 
-static int
+MODULE_SCOPE int
 ConvertUTCToLocal(
+    ClientData clientData,	/* Client data of the interpreter */
     Tcl_Interp *interp,		/* Tcl interpreter */
     TclDateFields *fields,	/* Fields of the time */
-    Tcl_Obj *tzdata,		/* Time zone data */
+    Tcl_Obj *timezoneObj,	/* Time zone */
     int changeover)		/* Julian Day of the Gregorian transition */
 {
+    ClockClientData *dataPtr = clientData;
+    Tcl_Obj *tzdata;		/* Time zone data */
     int rowc;			/* Number of rows in tzdata */
     Tcl_Obj **rowv;		/* Pointers to the rows */
 
+    /* fast phase-out for shared GMT-object (don't need to convert UTC 2 UTC) */
+    if (timezoneObj == dataPtr->GMTSetupTimeZone 
+	&& dataPtr->GMTSetupTimeZone != NULL 
+	&& dataPtr->GMTSetupTZData != NULL
+    ) {
+	fields->localSeconds = fields->seconds;
+	fields->tzOffset = 0;
+	if ( TclListObjGetElements(interp, dataPtr->GMTSetupTZData, &rowc, &rowv) != TCL_OK
+	  || Tcl_ListObjIndex(interp, rowv[0], 3, &fields->tzName) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	Tcl_IncrRefCount(fields->tzName);
+	return TCL_OK;
+    }
+
+    /*
+     * Check cacheable conversion could be used
+     * (last-period UTC2Local cache within the same TZ)
+     */
+    if ( timezoneObj == dataPtr->UTC2Local.timezoneObj
+      && ( fields->seconds == dataPtr->UTC2Local.seconds
+	|| ( fields->seconds >= dataPtr->UTC2Local.rangesVal[0]
+	  && fields->seconds <	dataPtr->UTC2Local.rangesVal[1])
+      )
+      && changeover == dataPtr->UTC2Local.changeover
+    ) {
+	/* the same time zone and offset (UTC time inside the last minute) */
+	Tcl_SetObjRef(fields->tzName, dataPtr->UTC2Local.tzName);
+	fields->tzOffset = dataPtr->UTC2Local.tzOffset;
+	fields->localSeconds = fields->seconds + fields->tzOffset;
+	return TCL_OK;
+    }
+
     /*
      * Unpack the tz data.
      */
 
+    tzdata = ClockGetTZData(clientData, interp, timezoneObj);
+    if (tzdata == NULL) {
+	return TCL_ERROR;
+    }
+
     if (TclListObjGetElements(interp, tzdata, &rowc, &rowv) != TCL_OK) {
 	return TCL_ERROR;
     }
@@ -967,10 +1994,26 @@ ConvertUTCToLocal(
      */
 
     if (rowc == 0) {
-	return ConvertUTCToLocalUsingC(interp, fields, changeover);
+	dataPtr->UTC2Local.rangesVal[0] = 0;
+	dataPtr->UTC2Local.rangesVal[1] = 0;
+
+	if (ConvertUTCToLocalUsingC(interp, fields, changeover) != TCL_OK) {
+	    return TCL_ERROR;
+	}
     } else {
-	return ConvertUTCToLocalUsingTable(interp, fields, rowc, rowv);
+	if (ConvertUTCToLocalUsingTable(interp, fields, rowc, rowv, 
+		dataPtr->UTC2Local.rangesVal) != TCL_OK) {
+	    return TCL_ERROR;
+    }
     }
+
+    /* Cache the last conversion */
+    Tcl_SetObjRef(dataPtr->UTC2Local.timezoneObj, timezoneObj);
+    dataPtr->UTC2Local.seconds = fields->seconds;
+    dataPtr->UTC2Local.changeover = changeover;
+    dataPtr->UTC2Local.tzOffset = fields->tzOffset;
+    Tcl_SetObjRef(dataPtr->UTC2Local.tzName, fields->tzName);
+    return TCL_OK;
 }
 
 /*
@@ -997,7 +2040,8 @@ ConvertUTCToLocalUsingTable(
     TclDateFields *fields,	/* Fields of the date */
     int rowc,			/* Number of rows in the conversion table
 				 * (>= 1) */
-    Tcl_Obj *const rowv[])	/* Rows of the conversion table */
+    Tcl_Obj *const rowv[],	/* Rows of the conversion table */
+    Tcl_WideInt rangesVal[2])	/* Return bounds for time period */
 {
     Tcl_Obj *row;		/* Row containing the current information */
     int cellc;			/* Count of cells in the row (must be 4) */
@@ -1007,7 +2051,7 @@ ConvertUTCToLocalUsingTable(
      * Look up the nearest transition time.
      */
 
-    row = LookupLastTransition(interp, fields->seconds, rowc, rowv);
+    row = LookupLastTransition(interp, fields->seconds, rowc, rowv, rangesVal);
     if (row == NULL ||
 	    TclListObjGetElements(interp, row, &cellc, &cellv) != TCL_OK ||
 	    TclGetIntFromObj(interp, cellv[1], &fields->tzOffset) != TCL_OK) {
@@ -1018,8 +2062,7 @@ ConvertUTCToLocalUsingTable(
      * Convert the time.
      */
 
-    fields->tzName = cellv[3];
-    Tcl_IncrRefCount(fields->tzName);
+    Tcl_SetObjRef(fields->tzName, cellv[3]);
     fields->localSeconds = fields->seconds + fields->tzOffset;
     return TCL_OK;
 }
@@ -1112,8 +2155,7 @@ ConvertUTCToLocalUsingC(
     if (diff > 0) {
 	sprintf(buffer+5, "%02d", diff);
     }
-    fields->tzName = Tcl_NewStringObj(buffer, -1);
-    Tcl_IncrRefCount(fields->tzName);
+    Tcl_SetObjRef(fields->tzName, Tcl_NewStringObj(buffer, -1));
     return TCL_OK;
 }
 
@@ -1131,24 +2173,25 @@ ConvertUTCToLocalUsingC(
  *----------------------------------------------------------------------
  */
 
-static Tcl_Obj *
+MODULE_SCOPE Tcl_Obj *
 LookupLastTransition(
     Tcl_Interp *interp,		/* Interpreter for error messages */
     Tcl_WideInt tick,		/* Time from the epoch */
     int rowc,			/* Number of rows of tzdata */
-    Tcl_Obj *const *rowv)	/* Rows in tzdata */
+    Tcl_Obj *const *rowv,	/* Rows in tzdata */
+    Tcl_WideInt rangesVal[2])	/* Return bounds for time period */
 {
-    int l;
+    int l = 0;
     int u;
     Tcl_Obj *compObj;
-    Tcl_WideInt compVal;
+    Tcl_WideInt compVal, fromVal = tick, toVal = tick;
 
     /*
      * Examine the first row to make sure we're in bounds.
      */
 
     if (Tcl_ListObjIndex(interp, rowv[0], 0, &compObj) != TCL_OK
-	    || Tcl_GetWideIntFromObj(interp, compObj, &compVal) != TCL_OK) {
+	    || TclGetWideIntFromObj(interp, compObj, &compVal) != TCL_OK) {
 	return NULL;
     }
 
@@ -1158,28 +2201,36 @@ LookupLastTransition(
      */
 
     if (tick < compVal) {
-	return rowv[0];
+	goto done;
     }
 
     /*
      * Binary-search to find the transition.
      */
 
-    l = 0;
     u = rowc-1;
     while (l < u) {
 	int m = (l + u + 1) / 2;
 
 	if (Tcl_ListObjIndex(interp, rowv[m], 0, &compObj) != TCL_OK ||
-		Tcl_GetWideIntFromObj(interp, compObj, &compVal) != TCL_OK) {
+		TclGetWideIntFromObj(interp, compObj, &compVal) != TCL_OK) {
 	    return NULL;
 	}
 	if (tick >= compVal) {
 	    l = m;
+	    fromVal = compVal;
 	} else {
 	    u = m-1;
+	    toVal = compVal;
 	}
     }
+
+done:
+
+    if (rangesVal) {
+	rangesVal[0] = fromVal;
+	rangesVal[1] = toVal;
+    }
     return rowv[l];
 }
 
@@ -1210,6 +2261,8 @@ GetYearWeekDay(
     TclDateFields temp;
     int dayOfFiscalYear;
 
+    temp.tzName = NULL;
+
     /*
      * Find the given date, minus three days, plus one year. That date's
      * iso8601 year is an upper bound on the ISO8601 year of the given date.
@@ -1416,7 +2469,7 @@ GetMonthDay(
  *----------------------------------------------------------------------
  */
 
-static void
+MODULE_SCOPE void
 GetJulianDayFromEraYearWeekDay(
     TclDateFields *fields,	/* Date to convert */
     int changeover)		/* Julian Day Number of the Gregorian
@@ -1426,6 +2479,8 @@ GetJulianDayFromEraYearWeekDay(
 				 * given year */
     TclDateFields firstWeek;
 
+    firstWeek.tzName = NULL;
+
     /*
      * Find January 4 in the ISO8601 year, which will always be in week 1.
      */
@@ -1467,7 +2522,7 @@ GetJulianDayFromEraYearWeekDay(
  *----------------------------------------------------------------------
  */
 
-static void
+MODULE_SCOPE void
 GetJulianDayFromEraYearMonthDay(
     TclDateFields *fields,	/* Date to convert */
     int changeover)		/* Gregorian transition date as a Julian Day */
@@ -1563,6 +2618,61 @@ GetJulianDayFromEraYearMonthDay(
 /*
  *----------------------------------------------------------------------
  *
+ * GetJulianDayFromEraYearDay --
+ *
+ *	Given era, year, and dayOfYear (in TclDateFields), and the
+ *	Gregorian transition date, computes the Julian Day Number.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Stores day number in 'julianDay'
+ *
+ *----------------------------------------------------------------------
+ */
+
+
+MODULE_SCOPE void
+GetJulianDayFromEraYearDay(
+    TclDateFields *fields,	/* Date to convert */
+    int changeover)		/* Gregorian transition date as a Julian Day */
+{
+    int year, ym1;
+
+    /* Get absolute year number from the civil year */
+    if (fields->era == BCE) {
+	year = 1 - fields->year;
+    } else {
+	year = fields->year;
+    }
+
+    ym1 = year - 1;
+
+    /* Try the Gregorian calendar first. */
+    fields->gregorian = 1;
+    fields->julianDay =
+	1721425
+	+ fields->dayOfYear
+	+ ( 365 * ym1 )
+	+ ( ym1 / 4 )
+	- ( ym1 / 100 )
+	+ ( ym1 / 400 );
+
+    /* If the date is before the Gregorian change, use the Julian calendar. */
+
+    if ( fields->julianDay < changeover ) {
+	fields->gregorian = 0;
+	fields->julianDay =
+	    1721423
+	    + fields->dayOfYear
+	    + ( 365 * ym1 )
+	    + ( ym1 / 4 );
+    }
+}
+/*
+ *----------------------------------------------------------------------
+ *
  * IsGregorianLeapYear --
  *
  *	Tests whether a given year is a leap year, in either Julian or
@@ -1574,16 +2684,14 @@ GetJulianDayFromEraYearMonthDay(
  *----------------------------------------------------------------------
  */
 
-static int
+MODULE_SCOPE int
 IsGregorianLeapYear(
     TclDateFields *fields)	/* Date to test */
 {
-    int year;
+    int year = fields->year;
 
     if (fields->era == BCE) {
-	year = 1 - fields->year;
-    } else {
-	year = fields->year;
+	year = 1 - year;
     }
     if (year%4 != 0) {
 	return 0;
@@ -1852,122 +2960,1030 @@ ClockMicrosecondsObjCmd(
     return TCL_OK;
 }
 
+static inline void
+ClockInitFmtScnArgs(
+    ClientData clientData,
+    Tcl_Interp *interp,
+    ClockFmtScnCmdArgs *opts)
+{
+    memset(opts, 0, sizeof(*opts));
+    opts->clientData = clientData;
+    opts->interp = interp;
+}
+
 /*
  *-----------------------------------------------------------------------------
  *
- * ClockParseformatargsObjCmd --
+ * ClockParseFmtScnArgs --
  *
- *	Parses the arguments for [clock format].
+ *	Parses the arguments for [clock scan] and [clock format].
  *
  * Results:
- *	Returns a standard Tcl result, whose value is a four-element list
- *	comprising the time format, the locale, and the timezone.
- *
- * This function exists because the loop that parses the [clock format]
- * options is a known performance "hot spot", and is implemented in an effort
- * to speed that particular code up.
+ *	Returns a standard Tcl result, and stores parsed options
+ *	(format, the locale, timezone and base) in structure "opts".
  *
  *-----------------------------------------------------------------------------
  */
 
+#define CLC_FMT_ARGS	(0)
+#define CLC_SCN_ARGS	(1 << 0)
+#define CLC_ADD_ARGS	(1 << 1)
+
 static int
-ClockParseformatargsObjCmd(
-    ClientData clientData,	/* Client data containing literal pool */
-    Tcl_Interp *interp,		/* Tcl interpreter */
+ClockParseFmtScnArgs(
+    register
+    ClockFmtScnCmdArgs *opts, /* Result vector: format, locale, timezone... */
+    TclDateFields      *date, /* Extracted date-time corresponding base 
+			       * (by scan or add) resp. clockval (by format) */
     int objc,			/* Parameter count */
-    Tcl_Obj *const objv[])	/* Parameter vector */
-{
-    ClockClientData *dataPtr = clientData;
-    Tcl_Obj **litPtr = dataPtr->literals;
-    Tcl_Obj *results[3];	/* Format, locale and timezone */
-#define formatObj results[0]
-#define localeObj results[1]
-#define timezoneObj results[2]
+    Tcl_Obj *const objv[],  /* Parameter vector */
+    int		flags	    /* Flags, differentiates between format, scan, add */
+) {
+    Tcl_Interp	    *interp =  opts->interp;
+    ClockClientData *dataPtr = opts->clientData;
     int gmtFlag = 0;
-    static const char *const options[] = { /* Command line options expected */
+    static const char *const options[] = {
 	"-format",	"-gmt",		"-locale",
-	"-timezone",	NULL };
+	"-timezone",	"-base",	NULL
+    };
     enum optionInd {
-	CLOCK_FORMAT_FORMAT,	CLOCK_FORMAT_GMT,	CLOCK_FORMAT_LOCALE,
-	CLOCK_FORMAT_TIMEZONE
+	CLC_ARGS_FORMAT,    CLC_ARGS_GMT,	CLC_ARGS_LOCALE,
+	CLC_ARGS_TIMEZONE,  CLC_ARGS_BASE
     };
     int optionIndex;		/* Index of an option. */
     int saw = 0;		/* Flag == 1 if option was seen already. */
-    Tcl_WideInt clockVal;	/* Clock value - just used to parse. */
     int i;
+    Tcl_WideInt baseVal;	/* Base time, expressed in seconds from the Epoch */
 
-    /*
-     * Args consist of a time followed by keyword-value pairs.
-     */
-
-    if (objc < 2 || (objc % 2) != 0) {
-	Tcl_WrongNumArgs(interp, 0, objv,
-		"clock format clockval ?-format string? "
-		"?-gmt boolean? ?-locale LOCALE? ?-timezone ZONE?");
-	Tcl_SetErrorCode(interp, "CLOCK", "wrongNumArgs", NULL);
-	return TCL_ERROR;
+    /* clock value (as current base) */
+    if ( !(flags & (CLC_SCN_ARGS)) ) {
+	opts->baseObj = objv[1];
+	saw |= (1 << CLC_ARGS_BASE);
     }
 
     /*
      * Extract values for the keywords.
      */
 
-    formatObj = litPtr[LIT__DEFAULT_FORMAT];
-    localeObj = litPtr[LIT_C];
-    timezoneObj = litPtr[LIT__NIL];
     for (i = 2; i < objc; i+=2) {
-	if (Tcl_GetIndexFromObj(interp, objv[i], options, "option", 0,
-		&optionIndex) != TCL_OK) {
-	    Tcl_SetErrorCode(interp, "CLOCK", "badOption",
-		    Tcl_GetString(objv[i]), NULL);
-	    return TCL_ERROR;
+	/* bypass integers (offsets) by "clock add" */
+	if (flags & CLC_ADD_ARGS) {
+	    Tcl_WideInt num;
+	    if (TclGetWideIntFromObj(NULL, objv[i], &num) == TCL_OK) {
+		continue;
+	}
+	}
+	/* get option */
+	if (Tcl_GetIndexFromObj(interp, objv[i], options, 
+	    "option", 0, &optionIndex) != TCL_OK) {
+	    goto badOption;
+	}
+	/* if already specified */
+	if (saw & (1 << optionIndex)) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"bad option \"%s\": doubly present", 
+		TclGetString(objv[i]))
+	    );
+	    goto badOption;
 	}
 	switch (optionIndex) {
-	case CLOCK_FORMAT_FORMAT:
-	    formatObj = objv[i+1];
+	case CLC_ARGS_FORMAT:
+	    if (flags & CLC_ADD_ARGS) {
+		goto badOptionMsg;
+	    }
+	    opts->formatObj = objv[i+1];
 	    break;
-	case CLOCK_FORMAT_GMT:
+	case CLC_ARGS_GMT:
 	    if (Tcl_GetBooleanFromObj(interp, objv[i+1], &gmtFlag) != TCL_OK){
 		return TCL_ERROR;
 	    }
 	    break;
-	case CLOCK_FORMAT_LOCALE:
-	    localeObj = objv[i+1];
+	case CLC_ARGS_LOCALE:
+	    opts->localeObj = objv[i+1];
 	    break;
-	case CLOCK_FORMAT_TIMEZONE:
-	    timezoneObj = objv[i+1];
+	case CLC_ARGS_TIMEZONE:
+	    opts->timezoneObj = objv[i+1];
 	    break;
+	case CLC_ARGS_BASE:
+	    if ( !(flags & (CLC_SCN_ARGS)) ) {
+		goto badOptionMsg;
 	}
-	saw |= 1 << optionIndex;
+	    opts->baseObj = objv[i+1];
+	    break;
+    }
+	saw |= (1 << optionIndex);
     }
 
     /*
      * Check options.
      */
 
-    if (Tcl_GetWideIntFromObj(interp, objv[1], &clockVal) != TCL_OK) {
-	return TCL_ERROR;
-    }
-    if ((saw & (1 << CLOCK_FORMAT_GMT))
-	    && (saw & (1 << CLOCK_FORMAT_TIMEZONE))) {
-	Tcl_SetObjResult(interp, litPtr[LIT_CANNOT_USE_GMT_AND_TIMEZONE]);
+    if ((saw & (1 << CLC_ARGS_GMT))
+	    && (saw & (1 << CLC_ARGS_TIMEZONE))) {
+	Tcl_SetResult(interp, "cannot use -gmt and -timezone in same call", TCL_STATIC);
 	Tcl_SetErrorCode(interp, "CLOCK", "gmtWithTimezone", NULL);
 	return TCL_ERROR;
     }
     if (gmtFlag) {
-	timezoneObj = litPtr[LIT_GMT];
+	opts->timezoneObj = dataPtr->literals[LIT_GMT];
+    }
+
+    /* If time zone not specified use system time zone */
+
+    if ( opts->timezoneObj == NULL
+      || TclGetString(opts->timezoneObj) == NULL 
+      || opts->timezoneObj->length == 0
+    ) {
+	opts->timezoneObj = ClockGetSystemTimeZone(opts->clientData, interp);
+	if (opts->timezoneObj == NULL) {
+	    return TCL_ERROR;
+	}
+    }
+
+    /* Setup timezone (normalize object if needed and load TZ on demand) */
+
+    opts->timezoneObj = ClockSetupTimeZone(opts->clientData, interp, opts->timezoneObj);
+    if (opts->timezoneObj == NULL) {
+	return TCL_ERROR;
+    }
+
+    /* Base (by scan or add) or clock value (by format) */
+
+    if (opts->baseObj != NULL) {
+	if (TclGetWideIntFromObj(NULL, opts->baseObj, &baseVal) != TCL_OK) {
+
+	    /* we accept "-now" as current date-time */
+	    const char *const nowOpts[] = {
+		"-now", NULL
+	    };
+	    int idx;
+	    if (Tcl_GetIndexFromObj(NULL, opts->baseObj, nowOpts, "seconds or -now",
+		    TCL_EXACT, &idx) == TCL_OK
+	    ) {
+		goto baseNow;
+	    }
+
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "expected integer but got \"%s\"",
+		    Tcl_GetString(opts->baseObj)));
+	    Tcl_SetErrorCode(interp, "TCL", "VALUE", "INTEGER", NULL);
+	    i = 1;
+	    goto badOption;
+	}
+    /*
+	 * seconds could be an unsigned number that overflowed. Make sure
+	 * that it isn't.
+     */
+
+	if (opts->baseObj->typePtr == &tclBignumType) {
+	    Tcl_SetObjResult(interp, dataPtr->literals[LIT_INTEGER_VALUE_TOO_LARGE]);
+	    return TCL_ERROR;
+	}
+
+    } else {
+
+baseNow:
+	{
+	    Tcl_Time now;
+	    Tcl_GetTime(&now);
+	    baseVal = (Tcl_WideInt) now.sec;
+	}
+    }
+
+    /*
+     * Extract year, month and day from the base time for the parser to use as
+     * defaults
+     */
+
+    /* check base fields already cached (by TZ, last-second cache) */
+    if ( dataPtr->lastBase.timezoneObj == opts->timezoneObj
+      && dataPtr->lastBase.Date.seconds == baseVal) {
+	memcpy(date, &dataPtr->lastBase.Date, ClockCacheableDateFieldsSize);
+    } else {
+	/* extact fields from base */
+	date->seconds = baseVal;
+	if (ClockGetDateFields(opts->clientData, interp, date, opts->timezoneObj,
+	      GREGORIAN_CHANGE_DATE) != TCL_OK) { /* TODO - GREGORIAN_CHANGE_DATE should be locale-dependent */
+	    return TCL_ERROR;
+	}
+	/* cache last base */
+	memcpy(&dataPtr->lastBase.Date, date, ClockCacheableDateFieldsSize);
+	Tcl_SetObjRef(dataPtr->lastBase.timezoneObj, opts->timezoneObj);
+    }
+
+    return TCL_OK;
+
+badOptionMsg: 
+
+    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+	"bad option \"%s\": unexpected for command \"%s\"",
+	TclGetString(objv[i]), TclGetString(objv[0]))
+    );
+
+badOption:
+
+    Tcl_SetErrorCode(interp, "CLOCK", "badOption",
+	    i < objc ? Tcl_GetString(objv[i]) : NULL, NULL);
+    
+    return TCL_ERROR;
+}
+
+/*----------------------------------------------------------------------
+ *
+ * ClockFormatObjCmd -- , clock format --
+ *
+ *	This function is invoked to process the Tcl "clock format" command.
+ *
+ *	Formats a count of seconds since the Posix Epoch as a time of day.
+ *
+ *	The 'clock format' command formats times of day for output.  Refer 
+ *	to the user documentation to see what it does.
+ *
+ * Results:
+ *	Returns a standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+ClockFormatObjCmd(
+    ClientData clientData,	/* Client data containing literal pool */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    int objc,			/* Parameter count */
+    Tcl_Obj *const objv[])	/* Parameter values */
+{
+    ClockClientData *dataPtr = clientData;
+
+    int ret;
+    ClockFmtScnCmdArgs opts;	/* Format, locale, timezone and base */
+    DateFormat	    dateFmt;	/* Common structure used for formatting */
+
+    /* even number of arguments */
+    if ((objc & 1) == 1) {
+	Tcl_WrongNumArgs(interp, 1, objv, "clockval|-now "
+	    "?-format string? "
+	    "?-gmt boolean? "
+	    "?-locale LOCALE? ?-timezone ZONE?");
+	Tcl_SetErrorCode(interp, "CLOCK", "wrongNumArgs", NULL);
+	return TCL_ERROR;
+    }
+
+    memset(&dateFmt, 0, sizeof(dateFmt));
+
+    /*
+     * Extract values for the keywords.
+     */
+
+    ClockInitFmtScnArgs(clientData, interp, &opts);
+    ret = ClockParseFmtScnArgs(&opts, &dateFmt.date, objc, objv,
+	    CLC_FMT_ARGS);
+    if (ret != TCL_OK) {
+	goto done;
+    }
+
+    /* Default format */
+    if (opts.formatObj == NULL) {
+	opts.formatObj = dataPtr->literals[LIT__DEFAULT_FORMAT];
+    }
+
+    /* Use compiled version of Format - */
+
+    ret = ClockFormat(&dateFmt, &opts);
+
+done:
+
+    Tcl_UnsetObjRef(dateFmt.date.tzName);
+
+    if (ret != TCL_OK) {
+	return ret;
+    }
+
+    return TCL_OK;
+}
+
+/*----------------------------------------------------------------------
+ *
+ * ClockScanObjCmd -- , clock scan --
+ *
+ *	This function is invoked to process the Tcl "clock scan" command.
+ *
+ *	Inputs a count of seconds since the Posix Epoch as a time of day.
+ *
+ *	The 'clock scan' command scans times of day on input. Refer to the
+ *	user documentation to see what it does.
+ *
+ * Results:
+ *	Returns a standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+ClockScanObjCmd(
+    ClientData clientData,	/* Client data containing literal pool */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    int objc,			/* Parameter count */
+    Tcl_Obj *const objv[])	/* Parameter values */
+{
+    int ret;
+    ClockFmtScnCmdArgs opts;	/* Format, locale, timezone and base */
+    DateInfo	    yy;		/* Common structure used for parsing */
+    DateInfo	   *info = &yy;
+
+    /* even number of arguments */
+    if ((objc & 1) == 1) {
+	Tcl_WrongNumArgs(interp, 1, objv, "string "
+	    "?-base seconds? "
+	    "?-format string? "
+	    "?-gmt boolean? "
+	    "?-locale LOCALE? ?-timezone ZONE?");
+	Tcl_SetErrorCode(interp, "CLOCK", "wrongNumArgs", NULL);
+	return TCL_ERROR;
+    }
+
+    ClockInitDateInfo(&yy);
+    
+    /*
+     * Extract values for the keywords.
+     */
+
+    ClockInitFmtScnArgs(clientData, interp, &opts);
+    ret = ClockParseFmtScnArgs(&opts, &yy.date, objc, objv,
+	    CLC_SCN_ARGS);
+    if (ret != TCL_OK) {
+	goto done;
+    }
+
+    /* seconds are in localSeconds (relative base date), so reset time here */
+    yyHour = 0; yyMinutes = 0; yySeconds = 0; yyMeridian = MER24;
+
+    /* If free scan */
+    if (opts.formatObj == NULL) {
+	/* Use compiled version of FreeScan - */
+
+	/* [SB] TODO: Perhaps someday we'll localize the legacy code. Right now, it's not localized. */
+	if (opts.localeObj != NULL) {
+	    Tcl_SetResult(interp,
+		"legacy [clock scan] does not support -locale", TCL_STATIC);
+	    Tcl_SetErrorCode(interp, "CLOCK", "flagWithLegacyFormat", NULL);
+	    return TCL_ERROR;
+	}
+	ret = ClockFreeScan(&yy, objv[1], &opts);
+    } 
+    else {
+	/* Use compiled version of Scan - */
+
+	ret = ClockScan(&yy, objv[1], &opts);
+    }
+
+    /* Convert date info structure into UTC seconds */
+
+    if (ret == TCL_OK) {
+	ret = ClockScanCommit(clientData, &yy, &opts);
+    }
+
+done:
+
+    Tcl_UnsetObjRef(yy.date.tzName);
+
+    if (ret != TCL_OK) {
+	return ret;
+    }
+
+    Tcl_SetObjResult(interp, Tcl_NewWideIntObj(yy.date.seconds));
+    return TCL_OK;
+}
+
+/*----------------------------------------------------------------------
+ *
+ * ClockScanCommit --
+ *
+ *	Converts date info structure into UTC seconds.
+ *
+ * Results:
+ *	Returns a standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+ClockScanCommit(
+    ClientData clientData,	/* Client data containing literal pool */
+    register DateInfo  *info,	/* Clock scan info structure */
+    register
+    ClockFmtScnCmdArgs *opts)	/* Format, locale, timezone and base */
+{
+    /* If needed assemble julianDay using year, month, etc. */
+    if (info->flags & CLF_ASSEMBLE_JULIANDAY) {
+	if ((info->flags & CLF_ISO8601)) {
+	    GetJulianDayFromEraYearWeekDay(&yydate, GREGORIAN_CHANGE_DATE);
+	}
+	else
+	if (!(info->flags & CLF_DAYOFYEAR)) {
+	    GetJulianDayFromEraYearMonthDay(&yydate, GREGORIAN_CHANGE_DATE);
+	} else {
+	    GetJulianDayFromEraYearDay(&yydate, GREGORIAN_CHANGE_DATE);
+	}
+    }
+
+    /* some overflow checks, if not extended */
+    if (!(opts->flags & CLF_EXTENDED)) {
+	if (yydate.julianDay > 5373484) {
+	    Tcl_SetObjResult(opts->interp, Tcl_NewStringObj(
+		"requested date too large to represent", -1));
+	    Tcl_SetErrorCode(opts->interp, "CLOCK", "dateTooLarge", NULL);
+	    return TCL_ERROR;
+	}
+    }
+
+    /* Local seconds to UTC (stored in yydate.seconds) */
+
+    if (info->flags & (CLF_ASSEMBLE_SECONDS|CLF_ASSEMBLE_JULIANDAY)) {
+	yydate.localSeconds =
+	    -210866803200L
+	    + ( SECONDS_PER_DAY * (Tcl_WideInt)yydate.julianDay )
+	    + ( yySeconds % SECONDS_PER_DAY );
+    }
+
+    if (info->flags & (CLF_ASSEMBLE_SECONDS|CLF_ASSEMBLE_JULIANDAY|CLF_LOCALSEC)) {
+	if (ConvertLocalToUTC(clientData, opts->interp, &yydate, opts->timezoneObj, 
+	      GREGORIAN_CHANGE_DATE) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+    }
+
+    /* Increment UTC seconds with relative time */
+    
+    yydate.seconds += yyRelSeconds;
+
+    return TCL_OK;
+}
+
+/*----------------------------------------------------------------------
+ *
+ * ClockFreeScan --
+ *
+ *	Used by ClockScanObjCmd for free scanning without format.
+ *
+ * Results:
+ *	Returns a standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+ClockFreeScan(
+    register
+    DateInfo	       *info,	/* Date fields used for parsing & converting
+				 * simultaneously a yy-parse structure of the 
+				 * TclClockFreeScan */	  
+    Tcl_Obj *strObj,		/* String containing the time to scan */
+    ClockFmtScnCmdArgs *opts)	/* Command options */
+{
+    Tcl_Interp	    *interp =  opts->interp;
+    ClockClientData *dataPtr = opts->clientData;
+
+    int ret = TCL_ERROR;
+
+    /*
+     * Parse the date. The parser will fill a structure "info" with date,
+     * time, time zone, relative month/day/seconds, relative weekday, ordinal
+     * month.
+     * Notice that many yy-defines point to values in the "info" or "date" 
+     * structure, e. g. yySeconds -> info->date.secondOfDay or 
+     *			yySeconds -> info->date.month (same as yydate.month)
+     */
+    yyInput = Tcl_GetString(strObj);
+
+    if (TclClockFreeScan(interp, info) != TCL_OK) {
+	Tcl_Obj *msg = Tcl_NewObj();
+	Tcl_AppendPrintfToObj(msg, "unable to convert date-time string \"%s\": %s", 
+	    Tcl_GetString(strObj), TclGetString(Tcl_GetObjResult(interp)));
+	Tcl_SetObjResult(interp, msg);
+	goto done;
+    }
+
+    /*
+     * If the caller supplied a date in the string, update the date with
+     * the value. If the caller didn't specify a time with the date, default to
+     * midnight.
+     */
+
+    if (yyHaveDate) {
+	if (yyYear < 100) {
+	    if (yyYear >= dataPtr->yearOfCenturySwitch) {
+		yyYear -= 100;
+	    }
+	    yyYear += dataPtr->currentYearCentury;
+	}
+	yydate.era = CE;
+	if (yyHaveTime == 0) {
+	    yyHaveTime = -1;
+	}
+	info->flags |= CLF_ASSEMBLE_JULIANDAY|CLF_ASSEMBLE_SECONDS;
+    }
+
+    /*
+     * If the caller supplied a time zone in the string, make it into a time 
+     * zone indicator of +-hhmm and setup this time zone.
+     */
+
+    if (yyHaveZone) {
+	Tcl_Obj *tzObjStor = NULL;
+	int minEast = -yyTimezone;
+	int dstFlag = 1 - yyDSTmode;
+	tzObjStor = ClockFormatNumericTimeZone(
+			  60 * minEast + 3600 * dstFlag);
+	Tcl_IncrRefCount(tzObjStor);
+
+	opts->timezoneObj = ClockSetupTimeZone(dataPtr, interp, tzObjStor);
+
+	Tcl_DecrRefCount(tzObjStor);
+	if (opts->timezoneObj == NULL) {
+	    goto done;
+	}
+
+	// Tcl_SetObjRef(yydate.tzName, opts->timezoneObj);
+
+	info->flags |= CLF_ASSEMBLE_SECONDS;
+    }
+    
+    /* 
+     * Assemble date, time, zone into seconds-from-epoch
+     */
+
+    if (yyHaveTime == -1) {
+	yySeconds = 0;
+	info->flags |= CLF_ASSEMBLE_SECONDS;
+    }
+    else
+    if (yyHaveTime) {
+	yySeconds = ToSeconds(yyHour, yyMinutes,
+			    yySeconds, yyMeridian);
+	info->flags |= CLF_ASSEMBLE_SECONDS;
+    } 
+    else 
+    if ( (yyHaveDay && !yyHaveDate)
+	    || yyHaveOrdinalMonth
+	    || ( yyHaveRel
+		&& ( yyRelMonth != 0
+		     || yyRelDay != 0 ) )
+    ) {
+	yySeconds = 0;
+	info->flags |= CLF_ASSEMBLE_SECONDS;
+    } 
+    else {
+	yySeconds = yydate.localSeconds % SECONDS_PER_DAY;
     }
 
     /*
-     * Return options as a list.
+     * Do relative times
      */
 
-    Tcl_SetObjResult(interp, Tcl_NewListObj(3, results));
+    ret = ClockCalcRelTime(info, opts);
+
+    /* Free scanning completed - date ready */
+
+done:
+
+    return ret;
+}
+
+/*----------------------------------------------------------------------
+ *
+ * ClockCalcRelTime --
+ *
+ *	Used for calculating of relative times.
+ *
+ * Results:
+ *	Returns a standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+int
+ClockCalcRelTime(
+    register
+    DateInfo	       *info,	/* Date fields used for converting */
+    ClockFmtScnCmdArgs *opts)	/* Command options */
+{
+    /*
+     * Because some calculations require in-between conversion of the
+     * julian day, we can repeat this processing multiple times 
+     */
+repeat_rel:
+
+    if (yyHaveRel) {
+
+	/* 
+	 * Relative conversion normally possible in UTC time only, because
+	 * of possible wrong local time increment if ignores in-between DST-hole.
+	 * (see test-cases clock-34.53, clock-34.54).
+	 * So increment date in julianDay, but time inside day in UTC (seconds).
+	 */
+
+	/* add months (or years in months) */
+
+	if (yyRelMonth != 0) {
+	    int m, h;
+
+	    /* if needed extract year, month, etc. again */
+	    if (info->flags & CLF_ASSEMBLE_DATE) {
+		GetGregorianEraYearDay(&yydate, GREGORIAN_CHANGE_DATE);
+		GetMonthDay(&yydate);
+		GetYearWeekDay(&yydate, GREGORIAN_CHANGE_DATE);
+		info->flags &= ~CLF_ASSEMBLE_DATE;
+	    }
+
+	    /* add the requisite number of months */
+	    yyMonth += yyRelMonth - 1;
+	    yyYear += yyMonth / 12;
+	    m = yyMonth % 12;
+	    yyMonth = m + 1;
+
+	    /* if the day doesn't exist in the current month, repair it */
+	    h = hath[IsGregorianLeapYear(&yydate)][m];
+	    if (yyDay > h) {
+		yyDay = h;
+	    }
+
+	    /* on demand (lazy) assemble julianDay using new year, month, etc. */
+	    info->flags |= CLF_ASSEMBLE_JULIANDAY|CLF_ASSEMBLE_SECONDS;
+
+	    yyRelMonth = 0;
+	}
+
+	/* add days (or other parts aligned to days) */
+	if (yyRelDay) {
+
+	    /* assemble julianDay using new year, month, etc. */
+	    if (info->flags & CLF_ASSEMBLE_JULIANDAY) {
+		GetJulianDayFromEraYearMonthDay(&yydate, GREGORIAN_CHANGE_DATE);
+		info->flags &= ~CLF_ASSEMBLE_JULIANDAY;
+	    }
+	    yydate.julianDay += yyRelDay;
+	    
+	    /* julianDay was changed, on demand (lazy) extract year, month, etc. again */
+	    info->flags |= CLF_ASSEMBLE_DATE|CLF_ASSEMBLE_SECONDS;
+
+	    yyRelDay = 0;
+	}
+
+	/* relative time (seconds), if exceeds current date, do the day conversion and
+	 * leave rest of the increment in yyRelSeconds to add it hereafter in UTC seconds */
+	if (yyRelSeconds) {
+	    int newSecs = yySeconds + yyRelSeconds;
+	       
+	    /* if seconds increment outside of current date, increment day */
+	    if (newSecs / SECONDS_PER_DAY != yySeconds / SECONDS_PER_DAY) {
+		
+		yyRelDay += newSecs / SECONDS_PER_DAY;
+		yySeconds = 0;		    
+		yyRelSeconds = newSecs % SECONDS_PER_DAY;
+
+		goto repeat_rel;
+	    }
+	}
+
+	yyHaveRel = 0;
+    }
+
+    /*
+     * Do relative (ordinal) month
+     */
+
+    if (yyHaveOrdinalMonth) {
+	int monthDiff;
+
+	/* if needed extract year, month, etc. again */
+	if (info->flags & CLF_ASSEMBLE_DATE) {
+	    GetGregorianEraYearDay(&yydate, GREGORIAN_CHANGE_DATE);
+	    GetMonthDay(&yydate);
+	    GetYearWeekDay(&yydate, GREGORIAN_CHANGE_DATE);
+	    info->flags &= ~CLF_ASSEMBLE_DATE;
+	}
+
+	if (yyMonthOrdinalIncr > 0) {
+	    monthDiff = yyMonthOrdinal - yyMonth;
+	    if (monthDiff <= 0) {
+		monthDiff += 12;
+	    }
+	    yyMonthOrdinalIncr--;
+	} else {
+	    monthDiff = yyMonth - yyMonthOrdinal;
+	    if (monthDiff >= 0) {
+		monthDiff -= 12;
+	    }
+	    yyMonthOrdinalIncr++;
+	}
+
+	/* process it further via relative times */
+	yyHaveRel++;
+	yyYear += yyMonthOrdinalIncr;
+	yyRelMonth += monthDiff;
+	yyHaveOrdinalMonth = 0;
+
+	info->flags |= CLF_ASSEMBLE_JULIANDAY|CLF_ASSEMBLE_SECONDS;
+
+	goto repeat_rel;
+    }
+
+    /*
+     * Do relative weekday
+     */
+
+    if (yyHaveDay && !yyHaveDate) {
+
+	/* if needed assemble julianDay now */
+	if (info->flags & CLF_ASSEMBLE_JULIANDAY) {
+	    GetJulianDayFromEraYearMonthDay(&yydate, GREGORIAN_CHANGE_DATE);
+	    info->flags &= ~CLF_ASSEMBLE_JULIANDAY;
+	}
+
+	yydate.era = CE;
+	yydate.julianDay = WeekdayOnOrBefore(yyDayNumber, yydate.julianDay + 6)
+		    + 7 * yyDayOrdinal;
+	if (yyDayOrdinal > 0) {
+	    yydate.julianDay -= 7;
+	}
+	info->flags |= CLF_ASSEMBLE_DATE|CLF_ASSEMBLE_SECONDS;
+    }
+
     return TCL_OK;
+}
 
-#undef timezoneObj
-#undef localeObj
-#undef formatObj
+
+/*----------------------------------------------------------------------
+ *
+ * ClockWeekdaysOffs --
+ *
+ *	Get offset in days for the number of week days corresponding the
+ *	given day of week (skipping Saturdays and Sundays).
+ *	
+ *
+ * Results:
+ *	Returns a day increment adjusted the given weekdays
+ *
+ *----------------------------------------------------------------------
+ */
+
+static inline int
+ClockWeekdaysOffs(
+    register int dayOfWeek,
+    register int offs)
+{
+    register int weeks, resDayOfWeek;
+
+    /* offset in days */
+    weeks = offs / 5;
+    offs = offs % 5;
+    /* compiler fix for negative offs - wrap (0, -1) -> (-1, 4) */
+    if (offs < 0) {
+	weeks--;
+	offs = 5 + offs;
+    }
+    offs += 7 * weeks;
+
+    /* resulting day of week */
+    {
+	register int day = (offs % 7);
+	/* compiler fix for negative offs - wrap (0, -1) -> (-1, 6) */
+	if (day < 0) {
+	    day = 7 + day;
+	}
+	resDayOfWeek = dayOfWeek + day;
+    }
+
+    /* adjust if we start from a weekend */
+    if (dayOfWeek > 5) {
+	int adj = 5 - dayOfWeek;
+	offs += adj;
+	resDayOfWeek += adj;
+    }
+
+    /* adjust if we end up on a weekend */
+    if (resDayOfWeek > 5) {
+       offs += 2;
+    }
+
+    return offs;
+}
+
+
+
+/*----------------------------------------------------------------------
+ *
+ * ClockAddObjCmd -- , clock add --
+ *
+ *	Adds an offset to a given time.
+ *
+ *	Refer to the user documentation to see what it exactly does.
+ *
+ * Syntax:
+ *   clock add clockval ?count unit?... ?-option value?
+ *
+ * Parameters:
+ *   clockval -- Starting time value
+ *   count -- Amount of a unit of time to add
+ *   unit -- Unit of time to add, must be one of:
+ *	     years year months month weeks week
+ *	     days day hours hour minutes minute
+ *	     seconds second
+ *
+ * Options:
+ *   -gmt BOOLEAN
+ *	 Flag synonymous with '-timezone :GMT'
+ *   -timezone ZONE
+ *	 Name of the time zone in which calculations are to be done.
+ *   -locale NAME
+ *	 Name of the locale in which calculations are to be done.
+ *	 Used to determine the Gregorian change date.
+ *
+ * Results:
+ *	Returns a standard Tcl result with the given time adjusted 
+ *	by the given offset(s) in order.
+ *
+ * Notes:
+ *   It is possible that adding a number of months or years will adjust the
+ *   day of the month as well.	For instance, the time at one month after
+ *   31 January is either 28 or 29 February, because February has fewer
+ *   than 31 days.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+ClockAddObjCmd(
+    ClientData clientData,	/* Client data containing literal pool */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    int objc,			/* Parameter count */
+    Tcl_Obj *const objv[])	/* Parameter values */
+{
+    ClockClientData *dataPtr = clientData;
+    int ret;
+    ClockFmtScnCmdArgs opts;	/* Format, locale, timezone and base */
+    DateInfo	    yy;		/* Common structure used for parsing */
+    DateInfo	   *info = &yy;
+
+    /* add "week" to units also (because otherwise ambiguous) */
+    static const char *const units[] = {
+	"years",	"months",	    "week",	    "weeks",
+	"days",		"weekdays",
+	"hours",	"minutes",	    "seconds",
+	NULL
+    };
+    enum unitInd {
+	CLC_ADD_YEARS,	CLC_ADD_MONTHS,	    CLC_ADD_WEEK,   CLC_ADD_WEEKS,
+	CLC_ADD_DAYS,	CLC_ADD_WEEKDAYS,
+	CLC_ADD_HOURS,	CLC_ADD_MINUTES,    CLC_ADD_SECONDS
+    };
+    int unitIndex;		/* Index of an option. */
+    int i;
+    Tcl_WideInt offs;
+
+    /* even number of arguments */
+    if ((objc & 1) == 1) {
+	Tcl_WrongNumArgs(interp, 1, objv, "clockval|-now ?number units?..."
+	    "?-gmt boolean? "
+	    "?-locale LOCALE? ?-timezone ZONE?");
+	Tcl_SetErrorCode(interp, "CLOCK", "wrongNumArgs", NULL);
+	return TCL_ERROR;
+    }
+
+    ClockInitDateInfo(&yy);
+    
+    /*
+     * Extract values for the keywords.
+     */
+
+    ClockInitFmtScnArgs(clientData, interp, &opts);
+    ret = ClockParseFmtScnArgs(&opts, &yy.date, objc, objv,
+	    CLC_ADD_ARGS);
+    if (ret != TCL_OK) {
+	goto done;
+    }
+
+    /* time together as seconds of the day */
+    yySeconds = yydate.localSeconds % SECONDS_PER_DAY;	 
+    /* seconds are in localSeconds (relative base date), so reset time here */
+    yyHour = 0; yyMinutes = 0; yyMeridian = MER24;
+
+    ret = TCL_ERROR;
+
+    /*
+     * Find each offset and process date increment
+     */
+
+    for (i = 2; i < objc; i+=2) {
+	/* bypass not integers (options, allready processed above) */
+	if (TclGetWideIntFromObj(NULL, objv[i], &offs) != TCL_OK) {
+	    continue;
+	}
+	if (objv[i]->typePtr == &tclBignumType) {
+	    Tcl_SetObjResult(interp, dataPtr->literals[LIT_INTEGER_VALUE_TOO_LARGE]);
+	    goto done;
+	}
+	/* get unit */
+	if (Tcl_GetIndexFromObj(interp, objv[i+1], units, "unit", 0,
+		&unitIndex) != TCL_OK) {
+	    goto done;
+	}
+
+	/* nothing to do if zero quantity */
+	if (!offs) {
+	    continue;
+	}
+
+	/* if in-between conversion needed (already have relative date/time), 
+	 * correct date info, because the date may be changed, 
+	 * so refresh it now */
+
+	if ( yyHaveRel
+	  && ( unitIndex == CLC_ADD_WEEKDAYS 
+	    /* some months can be shorter as another */
+	    || yyRelMonth || yyRelDay
+	    /* day changed */
+	    || yySeconds + yyRelSeconds > SECONDS_PER_DAY
+	    || yySeconds + yyRelSeconds < 0
+	  )
+	) {
+	    if (ClockCalcRelTime(info, &opts) != TCL_OK) {
+		goto done;
+	    }
+	}
+
+	/* process increment by offset + unit */
+	yyHaveRel++;
+	switch (unitIndex) {
+	case CLC_ADD_YEARS:
+	    yyRelMonth += offs * 12;
+	    break;
+	case CLC_ADD_MONTHS:
+	    yyRelMonth += offs;
+	    break;
+	case CLC_ADD_WEEK:
+	case CLC_ADD_WEEKS:
+	    yyRelDay += offs * 7;
+	    break;
+	case CLC_ADD_DAYS:
+	    yyRelDay += offs;
+	    break;
+	case CLC_ADD_WEEKDAYS:
+	    /* add number of week days (skipping Saturdays and Sundays)
+	     * to a relative days value. */
+	    offs = ClockWeekdaysOffs(yy.date.dayOfWeek, offs);
+	    yyRelDay += offs;
+	    break;
+	case CLC_ADD_HOURS:
+	    yyRelSeconds += offs * 60 * 60;
+	    break;
+	case CLC_ADD_MINUTES:
+	    yyRelSeconds += offs * 60;
+	    break;
+	case CLC_ADD_SECONDS:
+	    yyRelSeconds += offs;
+	    break;
+	}
+    }
+
+    /*
+     * Do relative times (if not yet already processed interim):
+     */
+
+    if (yyHaveRel) {
+	if (ClockCalcRelTime(info, &opts) != TCL_OK) {
+	    goto done;
+	}
+    }
+
+    /* Convert date info structure into UTC seconds */
+
+    ret = ClockScanCommit(clientData, &yy, &opts);
+
+done:
+
+    Tcl_UnsetObjRef(yy.date.tzName);
+
+    if (ret != TCL_OK) {
+	return ret;
+    }
+
+    Tcl_SetObjResult(interp, Tcl_NewWideIntObj(yy.date.seconds));
+    return TCL_OK;
 }
 
 /*----------------------------------------------------------------------
@@ -2009,7 +4025,7 @@ ClockSecondsObjCmd(
 /*
  *----------------------------------------------------------------------
  *
- * TzsetIfNecessary --
+ * TzsetGetEpoch --, TzsetIfNecessary --
  *
  *	Calls the tzset() library function if the contents of the TZ
  *	environment variable has changed.
@@ -2023,15 +4039,37 @@ ClockSecondsObjCmd(
  *----------------------------------------------------------------------
  */
 
-static void
-TzsetIfNecessary(void)
+static unsigned long
+TzsetGetEpoch(void)
 {
     static char* tzWas = INT2PTR(-1);	/* Previous value of TZ, protected by
 				 * clockMutex. */
+    static long	 tzLastRefresh = 0;	 /* Used for latency before next refresh */
+    static unsigned long tzWasEpoch = 0; /* Epoch, signals that TZ changed */
+    static unsigned long tzEnvEpoch = 0; /* Last env epoch, for faster signaling, 
+					    that TZ changed via TCL */
+    
     const char *tzIsNow;	/* Current value of TZ */
+    
+    /* 
+     * Prevent performance regression on some platforms by resolving of system time zone:
+     * small latency for check whether environment was changed (once per second)
+     * no latency if environment was chaned with tcl-env (compare both epoch values)
+     */
+    Tcl_Time now;
+    Tcl_GetTime(&now);
+    if (now.sec == tzLastRefresh && tzEnvEpoch == TclEnvEpoch) {
+	return tzWasEpoch;
+    }
+    tzEnvEpoch = TclEnvEpoch;
+    tzLastRefresh = now.sec;
 
+    /* check in lock */
     Tcl_MutexLock(&clockMutex);
+    tzIsNow = getenv("TCL_TZ");
+    if (tzIsNow == NULL) {
     tzIsNow = getenv("TZ");
+    }
     if (tzIsNow != NULL && (tzWas == NULL || tzWas == INT2PTR(-1)
 	    || strcmp(tzIsNow, tzWas) != 0)) {
 	tzset();
@@ -2040,43 +4078,21 @@ TzsetIfNecessary(void)
 	}
 	tzWas = ckalloc(strlen(tzIsNow) + 1);
 	strcpy(tzWas, tzIsNow);
+	tzWasEpoch++;
     } else if (tzIsNow == NULL && tzWas != NULL) {
 	tzset();
 	if (tzWas != INT2PTR(-1)) ckfree(tzWas);
 	tzWas = NULL;
+	tzWasEpoch++;
     }
     Tcl_MutexUnlock(&clockMutex);
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * ClockDeleteCmdProc --
- *
- *	Remove a reference to the clock client data, and clean up memory
- *	when it's all gone.
- *
- * Results:
- *	None.
- *
- *----------------------------------------------------------------------
- */
 
-static void
-ClockDeleteCmdProc(
-    ClientData clientData)	/* Opaque pointer to the client data */
+    return tzWasEpoch;
+}
+static void
+TzsetIfNecessary(void)
 {
-    ClockClientData *data = clientData;
-    int i;
-
-    data->refCount--;
-    if (data->refCount == 0) {
-	for (i = 0; i < LIT__END; ++i) {
-	    Tcl_DecrRefCount(data->literals[i]);
-	}
-	ckfree(data->literals);
-	ckfree(data);
-    }
+    TzsetGetEpoch();
 }
 
 /*
diff --git a/generic/tclDate.c b/generic/tclDate.c
index e4dd000..64cb804 100644
--- a/generic/tclDate.c
+++ b/generic/tclDate.c
@@ -1,24 +1,22 @@
-/* A Bison parser, made by GNU Bison 2.3.  */
+/* A Bison parser, made by GNU Bison 2.4.2.  */
 
 /* Skeleton implementation for Bison's Yacc-like parsers in C
-
-   Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006
-   Free Software Foundation, Inc.
-
-   This program is free software; you can redistribute it and/or modify
+   
+      Copyright (C) 1984, 1989-1990, 2000-2006, 2009-2010 Free Software
+   Foundation, Inc.
+   
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
-
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+   
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
-
+   
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 51 Franklin Street, Fifth Floor,
-   Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* As a special exception, you may create a larger work that contains
    part or all of the Bison parser skeleton and distribute that work
@@ -29,7 +27,7 @@
    special exception, which will cause the skeleton and the resulting
    Bison output files to be licensed under the GNU General Public
    License without this special exception.
-
+   
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
@@ -47,7 +45,7 @@
 #define YYBISON 1
 
 /* Bison version.  */
-#define YYBISON_VERSION "2.3"
+#define YYBISON_VERSION "2.4.2"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -55,65 +53,24 @@
 /* Pure parsers.  */
 #define YYPURE 1
 
+/* Push parsers.  */
+#define YYPUSH 0
+
+/* Pull parsers.  */
+#define YYPULL 1
+
 /* Using locations.  */
 #define YYLSP_NEEDED 1
 
 /* Substitute the variable and function names.  */
-#define yyparse TclDateparse
-#define yylex   TclDatelex
-#define yyerror TclDateerror
-#define yylval  TclDatelval
-#define yychar  TclDatechar
-#define yydebug TclDatedebug
-#define yynerrs TclDatenerrs
-#define yylloc TclDatelloc
-
-/* Tokens.  */
-#ifndef YYTOKENTYPE
-# define YYTOKENTYPE
-   /* Put the tokens into the symbol table, so that GDB and other debuggers
-      know about them.  */
-   enum yytokentype {
-     tAGO = 258,
-     tDAY = 259,
-     tDAYZONE = 260,
-     tID = 261,
-     tMERIDIAN = 262,
-     tMONTH = 263,
-     tMONTH_UNIT = 264,
-     tSTARDATE = 265,
-     tSEC_UNIT = 266,
-     tSNUMBER = 267,
-     tUNUMBER = 268,
-     tZONE = 269,
-     tEPOCH = 270,
-     tDST = 271,
-     tISOBASE = 272,
-     tDAY_UNIT = 273,
-     tNEXT = 274
-   };
-#endif
-/* Tokens.  */
-#define tAGO 258
-#define tDAY 259
-#define tDAYZONE 260
-#define tID 261
-#define tMERIDIAN 262
-#define tMONTH 263
-#define tMONTH_UNIT 264
-#define tSTARDATE 265
-#define tSEC_UNIT 266
-#define tSNUMBER 267
-#define tUNUMBER 268
-#define tZONE 269
-#define tEPOCH 270
-#define tDST 271
-#define tISOBASE 272
-#define tDAY_UNIT 273
-#define tNEXT 274
-
-
-
+#define yyparse         TclDateparse
+#define yylex           TclDatelex
+#define yyerror         TclDateerror
+#define yylval          TclDatelval
+#define yychar          TclDatechar
+#define yydebug         TclDatedebug
+#define yynerrs         TclDatenerrs
+#define yylloc          TclDatelloc
 
 /* Copy the first part of user declarations.  */
 
@@ -129,6 +86,7 @@
  *
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
  */
 #include "tclInt.h"
 
@@ -146,73 +104,11 @@
  * parsed fields will be returned.
  */
 
-typedef struct DateInfo {
-
-    Tcl_Obj* messages;		/* Error messages */
-    const char* separatrix;	/* String separating messages */
-
-    time_t dateYear;
-    time_t dateMonth;
-    time_t dateDay;
-    int dateHaveDate;
-
-    time_t dateHour;
-    time_t dateMinutes;
-    time_t dateSeconds;
-    int dateMeridian;
-    int dateHaveTime;
-
-    time_t dateTimezone;
-    int dateDSTmode;
-    int dateHaveZone;
-
-    time_t dateRelMonth;
-    time_t dateRelDay;
-    time_t dateRelSeconds;
-    int dateHaveRel;
-
-    time_t dateMonthOrdinal;
-    int dateHaveOrdinalMonth;
-
-    time_t dateDayOrdinal;
-    time_t dateDayNumber;
-    int dateHaveDay;
-
-    const char *dateStart;
-    const char *dateInput;
-    time_t *dateRelPointer;
-
-    int dateDigitCount;
-} DateInfo;
+#include "tclDate.h"
 
 #define YYMALLOC	ckalloc
 #define YYFREE(x)	(ckfree((void*) (x)))
 
-#define yyDSTmode	(info->dateDSTmode)
-#define yyDayOrdinal	(info->dateDayOrdinal)
-#define yyDayNumber	(info->dateDayNumber)
-#define yyMonthOrdinal	(info->dateMonthOrdinal)
-#define yyHaveDate	(info->dateHaveDate)
-#define yyHaveDay	(info->dateHaveDay)
-#define yyHaveOrdinalMonth (info->dateHaveOrdinalMonth)
-#define yyHaveRel	(info->dateHaveRel)
-#define yyHaveTime	(info->dateHaveTime)
-#define yyHaveZone	(info->dateHaveZone)
-#define yyTimezone	(info->dateTimezone)
-#define yyDay		(info->dateDay)
-#define yyMonth		(info->dateMonth)
-#define yyYear		(info->dateYear)
-#define yyHour		(info->dateHour)
-#define yyMinutes	(info->dateMinutes)
-#define yySeconds	(info->dateSeconds)
-#define yyMeridian	(info->dateMeridian)
-#define yyRelMonth	(info->dateRelMonth)
-#define yyRelDay	(info->dateRelDay)
-#define yyRelSeconds	(info->dateRelSeconds)
-#define yyRelPointer	(info->dateRelPointer)
-#define yyInput		(info->dateInput)
-#define yyDigitCount	(info->dateDigitCount)
-
 #define EPOCH		1970
 #define START_OF_TIME	1902
 #define END_OF_TIME	2037
@@ -246,13 +142,6 @@ typedef enum _DSTMODE {
     DSTon, DSToff, DSTmaybe
 } DSTMODE;
 
-/*
- * Meridian: am, pm, or 24-hour style.
- */
-
-typedef enum _MERIDIAN {
-    MERam, MERpm, MER24
-} MERIDIAN;
 
 
 
@@ -274,19 +163,49 @@ typedef enum _MERIDIAN {
 # define YYTOKEN_TABLE 0
 #endif
 
+
+/* Tokens.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+   /* Put the tokens into the symbol table, so that GDB and other debuggers
+      know about them.  */
+   enum yytokentype {
+     tAGO = 258,
+     tDAY = 259,
+     tDAYZONE = 260,
+     tID = 261,
+     tMERIDIAN = 262,
+     tMONTH = 263,
+     tMONTH_UNIT = 264,
+     tSTARDATE = 265,
+     tSEC_UNIT = 266,
+     tSNUMBER = 267,
+     tUNUMBER = 268,
+     tZONE = 269,
+     tEPOCH = 270,
+     tDST = 271,
+     tISOBASE = 272,
+     tDAY_UNIT = 273,
+     tNEXT = 274
+   };
+#endif
+
+
+
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 typedef union YYSTYPE
-
 {
+
+
     time_t Number;
     enum _MERIDIAN Meridian;
-}
-/* Line 187 of yacc.c.  */
 
-	YYSTYPE;
+
+
+} YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
-# define YYSTYPE_IS_TRIVIAL 1
 #endif
 
 #if ! defined YYLTYPE && ! defined YYLTYPE_IS_DECLARED
@@ -316,14 +235,10 @@ static int		LookupWord(YYSTYPE* yylvalPtr, char *buff);
 				     DateInfo* info, const char *s);
  static int		TclDatelex(YYSTYPE* yylvalPtr, YYLTYPE* location,
 				   DateInfo* info);
-static time_t		ToSeconds(time_t Hours, time_t Minutes,
-			    time_t Seconds, MERIDIAN Meridian);
 MODULE_SCOPE int	yyparse(DateInfo*);
 
 
 
-/* Line 216 of yacc.c.  */
-
 
 #ifdef short
 # undef short
@@ -359,15 +274,21 @@ typedef short int yytype_int16;
 #ifndef YYSIZE_T
 # ifdef __SIZE_TYPE__
 #  define YYSIZE_T __SIZE_TYPE__
-# else
+# elif defined size_t
+#  define YYSIZE_T size_t
+# elif ! defined YYSIZE_T && (defined __STDC__ || defined __C99__FUNC__ \
+     || defined __cplusplus || defined _MSC_VER)
+#  include <stddef.h> /* INFRINGES ON USER NAME SPACE */
 #  define YYSIZE_T size_t
+# else
+#  define YYSIZE_T unsigned int
 # endif
 #endif
 
 #define YYSIZE_MAXIMUM ((YYSIZE_T) -1)
 
 #ifndef YY_
-# if YYENABLE_NLS
+# if defined YYENABLE_NLS && YYENABLE_NLS
 #  if ENABLE_NLS
 #   include <libintl.h> /* INFRINGES ON USER NAME SPACE */
 #   define YY_(msgid) dgettext ("bison-runtime", msgid)
@@ -392,14 +313,14 @@ typedef short int yytype_int16;
 #if (defined __STDC__ || defined __C99__FUNC__ \
      || defined __cplusplus || defined _MSC_VER)
 static int
-YYID (int i)
+YYID (int yyi)
 #else
 static int
-YYID (i)
-    int i;
+YYID (yyi)
+    int yyi;
 #endif
 {
-  return i;
+  return yyi;
 }
 #endif
 
@@ -481,9 +402,9 @@ void free (void *); /* INFRINGES ON USER NAME SPACE */
 /* A type that is properly aligned for any stack member.  */
 union yyalloc
 {
-  yytype_int16 yyss;
-  YYSTYPE yyvs;
-    YYLTYPE yyls;
+  yytype_int16 yyss_alloc;
+  YYSTYPE yyvs_alloc;
+  YYLTYPE yyls_alloc;
 };
 
 /* The size of the maximum gap between one aligned stack and the next.  */
@@ -518,12 +439,12 @@ union yyalloc
    elements in the stack, and YYPTR gives the new location of the
    stack.  Advance YYPTR to a properly aligned location for the next
    stack.  */
-# define YYSTACK_RELOCATE(Stack)					\
+# define YYSTACK_RELOCATE(Stack_alloc, Stack)				\
     do									\
       {									\
 	YYSIZE_T yynewbytes;						\
-	YYCOPY (&yyptr->Stack, Stack, yysize);				\
-	Stack = &yyptr->Stack;						\
+	YYCOPY (&yyptr->Stack_alloc, Stack, yysize);			\
+	Stack = &yyptr->Stack_alloc;					\
 	yynewbytes = yystacksize * sizeof (*Stack) + YYSTACK_GAP_MAXIMUM; \
 	yyptr += yynewbytes / sizeof (*yyptr);				\
       }									\
@@ -624,12 +545,12 @@ static const yytype_int8 yyrhs[] =
 /* YYRLINE[YYN] -- source line where rule number YYN was defined.  */
 static const yytype_uint16 yyrline[] =
 {
-       0,   225,   225,   226,   229,   232,   235,   238,   241,   244,
-     247,   251,   256,   259,   265,   271,   279,   285,   296,   300,
-     304,   310,   314,   318,   322,   326,   332,   336,   341,   346,
-     351,   356,   360,   365,   369,   374,   381,   385,   391,   400,
-     409,   419,   433,   438,   441,   444,   447,   450,   453,   458,
-     461,   466,   470,   474,   480,   498,   501
+       0,   152,   152,   153,   156,   159,   162,   165,   168,   171,
+     174,   178,   183,   186,   192,   198,   206,   212,   223,   227,
+     231,   237,   241,   245,   249,   253,   259,   263,   268,   273,
+     278,   283,   287,   292,   296,   301,   308,   312,   318,   327,
+     336,   346,   360,   365,   368,   371,   374,   377,   380,   385,
+     388,   393,   397,   401,   407,   425,   428
 };
 #endif
 
@@ -783,9 +704,18 @@ static const yytype_uint8 yystos[] =
 
 /* Like YYERROR except do call yyerror.  This remains here temporarily
    to ease the transition to the new meaning of YYERROR, for GCC.
-   Once GCC version 2 has supplanted version 1, this can go.  */
+   Once GCC version 2 has supplanted version 1, this can go.  However,
+   YYFAIL appears to be in use.  Nevertheless, it is formally deprecated
+   in Bison 2.4.2's NEWS entry, where a plan to phase it out is
+   discussed.  */
 
 #define YYFAIL		goto yyerrlab
+#if defined YYFAIL
+  /* This is here to suppress warnings from the GCC cpp's
+     -Wunused-macros.  Normally we don't worry about that warning, but
+     some users do, and we want to make it easy for users to remove
+     YYFAIL uses, which will produce warnings from Bison 2.5.  */
+#endif
 
 #define YYRECOVERING()  (!!yyerrstatus)
 
@@ -842,7 +772,7 @@ while (YYID (0))
    we won't break user code: when these are the locations we know.  */
 
 #ifndef YY_LOCATION_PRINT
-# if YYLTYPE_IS_TRIVIAL
+# if defined YYLTYPE_IS_TRIVIAL && YYLTYPE_IS_TRIVIAL
 #  define YY_LOCATION_PRINT(File, Loc)			\
      fprintf (File, "%d.%d-%d.%d",			\
 	      (Loc).first_line, (Loc).first_column,	\
@@ -961,17 +891,20 @@ yy_symbol_print (yyoutput, yytype, yyvaluep, yylocationp, info)
 #if (defined __STDC__ || defined __C99__FUNC__ \
      || defined __cplusplus || defined _MSC_VER)
 static void
-yy_stack_print (yytype_int16 *bottom, yytype_int16 *top)
+yy_stack_print (yytype_int16 *yybottom, yytype_int16 *yytop)
 #else
 static void
-yy_stack_print (bottom, top)
-    yytype_int16 *bottom;
-    yytype_int16 *top;
+yy_stack_print (yybottom, yytop)
+    yytype_int16 *yybottom;
+    yytype_int16 *yytop;
 #endif
 {
   YYFPRINTF (stderr, "Stack now");
-  for (; bottom <= top; ++bottom)
-    YYFPRINTF (stderr, " %d", *bottom);
+  for (; yybottom <= yytop; yybottom++)
+    {
+      int yybot = *yybottom;
+      YYFPRINTF (stderr, " %d", yybot);
+    }
   YYFPRINTF (stderr, "\n");
 }
 
@@ -1007,11 +940,11 @@ yy_reduce_print (yyvsp, yylsp, yyrule, info)
   /* The symbols being reduced.  */
   for (yyi = 0; yyi < yynrhs; yyi++)
     {
-      fprintf (stderr, "   $%d = ", yyi + 1);
+      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
       yy_symbol_print (stderr, yyrhs[yyprhs[yyrule] + yyi],
 		       &(yyvsp[(yyi + 1) - (yynrhs)])
 		       , &(yylsp[(yyi + 1) - (yynrhs)])		       , info);
-      fprintf (stderr, "\n");
+      YYFPRINTF (stderr, "\n");
     }
 }
 
@@ -1295,10 +1228,8 @@ yydestruct (yymsg, yytype, yyvaluep, yylocationp, info)
 	break;
     }
 }
-
 
 /* Prevent warnings from -Wmissing-prototypes.  */
-
 #ifdef YYPARSE_PARAM
 #if defined __STDC__ || defined __cplusplus
 int yyparse (void *YYPARSE_PARAM);
@@ -1317,10 +1248,9 @@ int yyparse ();
 
 
 
-
-/*----------.
-| yyparse.  |
-`----------*/
+/*-------------------------.
+| yyparse or yypush_parse.  |
+`-------------------------*/
 
 #ifdef YYPARSE_PARAM
 #if (defined __STDC__ || defined __C99__FUNC__ \
@@ -1344,88 +1274,97 @@ yyparse (info)
 #endif
 #endif
 {
-  /* The look-ahead symbol.  */
+/* The lookahead symbol.  */
 int yychar;
 
-/* The semantic value of the look-ahead symbol.  */
+/* The semantic value of the lookahead symbol.  */
 YYSTYPE yylval;
 
-/* Number of syntax errors so far.  */
-int yynerrs;
-/* Location data for the look-ahead symbol.  */
+/* Location data for the lookahead symbol.  */
 YYLTYPE yylloc;
 
-  int yystate;
-  int yyn;
-  int yyresult;
-  /* Number of tokens to shift before error messages enabled.  */
-  int yyerrstatus;
-  /* Look-ahead token as an internal (translated) token number.  */
-  int yytoken = 0;
-#if YYERROR_VERBOSE
-  /* Buffer for error messages, and its allocated size.  */
-  char yymsgbuf[128];
-  char *yymsg = yymsgbuf;
-  YYSIZE_T yymsg_alloc = sizeof yymsgbuf;
-#endif
+    /* Number of syntax errors so far.  */
+    int yynerrs;
 
-  /* Three stacks and their tools:
-     `yyss': related to states,
-     `yyvs': related to semantic values,
-     `yyls': related to locations.
+    int yystate;
+    /* Number of tokens to shift before error messages enabled.  */
+    int yyerrstatus;
 
-     Refer to the stacks thru separate pointers, to allow yyoverflow
-     to reallocate them elsewhere.  */
+    /* The stacks and their tools:
+       `yyss': related to states.
+       `yyvs': related to semantic values.
+       `yyls': related to locations.
 
-  /* The state stack.  */
-  yytype_int16 yyssa[YYINITDEPTH];
-  yytype_int16 *yyss = yyssa;
-  yytype_int16 *yyssp;
+       Refer to the stacks thru separate pointers, to allow yyoverflow
+       to reallocate them elsewhere.  */
 
-  /* The semantic value stack.  */
-  YYSTYPE yyvsa[YYINITDEPTH];
-  YYSTYPE *yyvs = yyvsa;
-  YYSTYPE *yyvsp;
+    /* The state stack.  */
+    yytype_int16 yyssa[YYINITDEPTH];
+    yytype_int16 *yyss;
+    yytype_int16 *yyssp;
 
-  /* The location stack.  */
-  YYLTYPE yylsa[YYINITDEPTH];
-  YYLTYPE *yyls = yylsa;
-  YYLTYPE *yylsp;
-  /* The locations where the error started and ended.  */
-  YYLTYPE yyerror_range[2];
+    /* The semantic value stack.  */
+    YYSTYPE yyvsa[YYINITDEPTH];
+    YYSTYPE *yyvs;
+    YYSTYPE *yyvsp;
 
-#define YYPOPSTACK(N)   (yyvsp -= (N), yyssp -= (N), yylsp -= (N))
+    /* The location stack.  */
+    YYLTYPE yylsa[YYINITDEPTH];
+    YYLTYPE *yyls;
+    YYLTYPE *yylsp;
 
-  YYSIZE_T yystacksize = YYINITDEPTH;
+    /* The locations where the error started and ended.  */
+    YYLTYPE yyerror_range[2];
 
+    YYSIZE_T yystacksize;
+
+  int yyn;
+  int yyresult;
+  /* Lookahead token as an internal (translated) token number.  */
+  int yytoken;
   /* The variables used to return semantic value and location from the
      action routines.  */
   YYSTYPE yyval;
   YYLTYPE yyloc;
 
+#if YYERROR_VERBOSE
+  /* Buffer for error messages, and its allocated size.  */
+  char yymsgbuf[128];
+  char *yymsg = yymsgbuf;
+  YYSIZE_T yymsg_alloc = sizeof yymsgbuf;
+#endif
+
+#define YYPOPSTACK(N)   (yyvsp -= (N), yyssp -= (N), yylsp -= (N))
+
   /* The number of symbols on the RHS of the reduced rule.
      Keep to zero when no symbol should be popped.  */
   int yylen = 0;
 
+  yytoken = 0;
+  yyss = yyssa;
+  yyvs = yyvsa;
+  yyls = yylsa;
+  yystacksize = YYINITDEPTH;
+
   YYDPRINTF ((stderr, "Starting parse\n"));
 
   yystate = 0;
   yyerrstatus = 0;
   yynerrs = 0;
-  yychar = YYEMPTY;		/* Cause a token to be read.  */
+  yychar = YYEMPTY; /* Cause a token to be read.  */
 
   /* Initialize stack pointers.
      Waste one element of value and location stack
      so that they stay on the same level as the state stack.
      The wasted elements are never initialized.  */
-
   yyssp = yyss;
   yyvsp = yyvs;
   yylsp = yyls;
-#if YYLTYPE_IS_TRIVIAL
+
+#if defined YYLTYPE_IS_TRIVIAL && YYLTYPE_IS_TRIVIAL
   /* Initialize the default location before parsing starts.  */
   yylloc.first_line   = yylloc.last_line   = 1;
-  yylloc.first_column = yylloc.last_column = 0;
+  yylloc.first_column = yylloc.last_column = 1;
 #endif
 
   goto yysetstate;
@@ -1464,6 +1403,7 @@ YYLTYPE yylloc;
 		    &yyvs1, yysize * sizeof (*yyvsp),
 		    &yyls1, yysize * sizeof (*yylsp),
 		    &yystacksize);
+
 	yyls = yyls1;
 	yyss = yyss1;
 	yyvs = yyvs1;
@@ -1485,9 +1425,9 @@ YYLTYPE yylloc;
 	  (union yyalloc *) YYSTACK_ALLOC (YYSTACK_BYTES (yystacksize));
 	if (! yyptr)
 	  goto yyexhaustedlab;
-	YYSTACK_RELOCATE (yyss);
-	YYSTACK_RELOCATE (yyvs);
-	YYSTACK_RELOCATE (yyls);
+	YYSTACK_RELOCATE (yyss_alloc, yyss);
+	YYSTACK_RELOCATE (yyvs_alloc, yyvs);
+	YYSTACK_RELOCATE (yyls_alloc, yyls);
 #  undef YYSTACK_RELOCATE
 	if (yyss1 != yyssa)
 	  YYSTACK_FREE (yyss1);
@@ -1508,6 +1448,9 @@ YYLTYPE yylloc;
 
   YYDPRINTF ((stderr, "Entering state %d\n", yystate));
 
+  if (yystate == YYFINAL)
+    YYACCEPT;
+
   goto yybackup;
 
 /*-----------.
@@ -1516,16 +1459,16 @@ YYLTYPE yylloc;
 yybackup:
 
   /* Do appropriate processing given the current state.  Read a
-     look-ahead token if we need one and don't already have one.  */
+     lookahead token if we need one and don't already have one.  */
 
-  /* First try to decide what to do without reference to look-ahead token.  */
+  /* First try to decide what to do without reference to lookahead token.  */
   yyn = yypact[yystate];
   if (yyn == YYPACT_NINF)
     goto yydefault;
 
-  /* Not known => get a look-ahead token if don't already have one.  */
+  /* Not known => get a lookahead token if don't already have one.  */
 
-  /* YYCHAR is either YYEMPTY or YYEOF or a valid look-ahead symbol.  */
+  /* YYCHAR is either YYEMPTY or YYEOF or a valid lookahead symbol.  */
   if (yychar == YYEMPTY)
     {
       YYDPRINTF ((stderr, "Reading a token: "));
@@ -1557,20 +1500,16 @@ yybackup:
       goto yyreduce;
     }
 
-  if (yyn == YYFINAL)
-    YYACCEPT;
-
   /* Count tokens shifted since error; after three, turn off error
      status.  */
   if (yyerrstatus)
     yyerrstatus--;
 
-  /* Shift the look-ahead token.  */
+  /* Shift the lookahead token.  */
   YY_SYMBOL_PRINT ("Shifting", yytoken, &yylval, &yylloc);
 
-  /* Discard the shifted token unless it is eof.  */
-  if (yychar != YYEOF)
-    yychar = YYEMPTY;
+  /* Discard the shifted token.  */
+  yychar = YYEMPTY;
 
   yystate = yyn;
   *++yyvsp = yylval;
@@ -1878,16 +1817,16 @@ yyreduce:
   case 36:
 
     {
-	    yyMonthOrdinal = 1;
-	    yyMonth = (yyvsp[(2) - (2)].Number);
+	    yyMonthOrdinalIncr = 1;
+	    yyMonthOrdinal = (yyvsp[(2) - (2)].Number);
 	;}
     break;
 
   case 37:
 
     {
-	    yyMonthOrdinal = (yyvsp[(2) - (3)].Number);
-	    yyMonth = (yyvsp[(3) - (3)].Number);
+	    yyMonthOrdinalIncr = (yyvsp[(2) - (3)].Number);
+	    yyMonthOrdinal = (yyvsp[(3) - (3)].Number);
 	;}
     break;
 
@@ -2062,7 +2001,6 @@ yyreduce:
     break;
 
 
-/* Line 1267 of yacc.c.  */
 
       default: break;
     }
@@ -2139,7 +2077,7 @@ yyerrlab:
 
   if (yyerrstatus == 3)
     {
-      /* If just tried and failed to reuse look-ahead token after an
+      /* If just tried and failed to reuse lookahead token after an
 	 error, discard it.  */
 
       if (yychar <= YYEOF)
@@ -2156,7 +2094,7 @@ yyerrlab:
 	}
     }
 
-  /* Else will try to reuse look-ahead token after shifting the error
+  /* Else will try to reuse lookahead token after shifting the error
      token.  */
   goto yyerrlab1;
 
@@ -2214,14 +2152,11 @@ yyerrlab1:
       YY_STACK_PRINT (yyss, yyssp);
     }
 
-  if (yyn == YYFINAL)
-    YYACCEPT;
-
   *++yyvsp = yylval;
 
   yyerror_range[1] = yylloc;
   /* Using YYLLOC is tempting, but would change the location of
-     the look-ahead.  YYLOC is available though.  */
+     the lookahead.  YYLOC is available though.  */
   YYLLOC_DEFAULT (yyloc, (yyerror_range - 1), 2);
   *++yylsp = yyloc;
 
@@ -2246,7 +2181,7 @@ yyabortlab:
   yyresult = 1;
   goto yyreturn;
 
-#ifndef yyoverflow
+#if !defined(yyoverflow) || YYERROR_VERBOSE
 /*-------------------------------------------------.
 | yyexhaustedlab -- memory exhaustion comes here.  |
 `-------------------------------------------------*/
@@ -2257,7 +2192,7 @@ yyexhaustedlab:
 #endif
 
 yyreturn:
-  if (yychar != YYEOF && yychar != YYEMPTY)
+  if (yychar != YYEMPTY)
      yydestruct ("Cleanup: discarding lookahead",
 		 yytoken, &yylval, &yylloc, info);
   /* Do not reclaim the symbols of the rule which action triggered
@@ -2513,11 +2448,11 @@ TclDateerror(
     infoPtr->separatrix = "\n";
 }
 
-static time_t
+MODULE_SCOPE int
 ToSeconds(
-    time_t Hours,
-    time_t Minutes,
-    time_t Seconds,
+    int Hours,
+    int Minutes,
+    int Seconds,
     MERIDIAN Meridian)
 {
     if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 59) {
@@ -2680,7 +2615,7 @@ TclDatelex(
 
     location->first_column = yyInput - info->dateStart;
     for ( ; ; ) {
-	while (TclIsSpaceProc(*yyInput)) {
+	while (isspace(UCHAR(*yyInput))) {
 	    yyInput++;
 	}
 
@@ -2740,65 +2675,36 @@ TclDatelex(
 	} while (Count > 0);
     }
 }
-
+
 int
-TclClockOldscanObjCmd(
-    ClientData clientData,	/* Unused */
+TclClockFreeScan(
     Tcl_Interp *interp,		/* Tcl interpreter */
-    int objc,			/* Count of paraneters */
-    Tcl_Obj *const *objv)	/* Parameters */
+    DateInfo *info)		/* Input and result parameters */
 {
-    Tcl_Obj *result, *resultElement;
-    int yr, mo, da;
-    DateInfo dateInfo;
-    DateInfo* info = &dateInfo;
     int status;
 
-    if (objc != 5) {
-	Tcl_WrongNumArgs(interp, 1, objv,
-		"stringToParse baseYear baseMonth baseDay" );
-	return TCL_ERROR;
-    }
-
-    yyInput = Tcl_GetString( objv[1] );
-    dateInfo.dateStart = yyInput;
-
-    yyHaveDate = 0;
-    if (Tcl_GetIntFromObj(interp, objv[2], &yr) != TCL_OK
-	    || Tcl_GetIntFromObj(interp, objv[3], &mo) != TCL_OK
-	    || Tcl_GetIntFromObj(interp, objv[4], &da) != TCL_OK) {
-	return TCL_ERROR;
-    }
-    yyYear = yr; yyMonth = mo; yyDay = da;
-
-    yyHaveTime = 0;
-    yyHour = 0; yyMinutes = 0; yySeconds = 0; yyMeridian = MER24;
-
-    yyHaveZone = 0;
-    yyTimezone = 0; yyDSTmode = DSTmaybe;
-
-    yyHaveOrdinalMonth = 0;
-    yyMonthOrdinal = 0;
-
-    yyHaveDay = 0;
-    yyDayOrdinal = 0; yyDayNumber = 0;
+    /*
+     * yyInput = stringToParse;
+     * 
+     * ClockInitDateInfo(info) should be executed to pre-init info;
+     */
 
-    yyHaveRel = 0;
-    yyRelMonth = 0; yyRelDay = 0; yyRelSeconds = 0; yyRelPointer = NULL;
+    yyDSTmode = DSTmaybe;
 
-    dateInfo.messages = Tcl_NewObj();
-    dateInfo.separatrix = "";
-    Tcl_IncrRefCount(dateInfo.messages);
+    info->messages = Tcl_NewObj();
+    info->separatrix = "";
+    Tcl_IncrRefCount(info->messages);
 
-    status = yyparse(&dateInfo);
+    info->dateStart = yyInput;
+    status = yyparse(info);
     if (status == 1) {
-	Tcl_SetObjResult(interp, dateInfo.messages);
-	Tcl_DecrRefCount(dateInfo.messages);
+	Tcl_SetObjResult(interp, info->messages);
+	Tcl_DecrRefCount(info->messages);
 	Tcl_SetErrorCode(interp, "TCL", "VALUE", "DATE", "PARSE", NULL);
 	return TCL_ERROR;
     } else if (status == 2) {
 	Tcl_SetObjResult(interp, Tcl_NewStringObj("memory exhausted", -1));
-	Tcl_DecrRefCount(dateInfo.messages);
+	Tcl_DecrRefCount(info->messages);
 	Tcl_SetErrorCode(interp, "TCL", "MEMORY", NULL);
 	return TCL_ERROR;
     } else if (status != 0) {
@@ -2806,11 +2712,11 @@ TclClockOldscanObjCmd(
 						  "from date parser. Please "
 						  "report this error as a "
 						  "bug in Tcl.", -1));
-	Tcl_DecrRefCount(dateInfo.messages);
+	Tcl_DecrRefCount(info->messages);
 	Tcl_SetErrorCode(interp, "TCL", "BUG", NULL);
 	return TCL_ERROR;
     }
-    Tcl_DecrRefCount(dateInfo.messages);
+    Tcl_DecrRefCount(info->messages);
 
     if (yyHaveDate > 1) {
 	Tcl_SetObjResult(interp,
@@ -2843,6 +2749,40 @@ TclClockOldscanObjCmd(
 	return TCL_ERROR;
     }
 
+    return TCL_OK;
+}
+
+int
+TclClockOldscanObjCmd(
+    ClientData clientData,	/* Unused */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    int objc,			/* Count of paraneters */
+    Tcl_Obj *const *objv)	/* Parameters */
+{
+    Tcl_Obj *result, *resultElement;
+    int yr, mo, da;
+    DateInfo dateInfo;
+    DateInfo* info = &dateInfo;
+
+    if (objc != 5) {
+	Tcl_WrongNumArgs(interp, 1, objv,
+		"stringToParse baseYear baseMonth baseDay" );
+	return TCL_ERROR;
+    }
+
+    yyInput = Tcl_GetString( objv[1] );
+
+    if (Tcl_GetIntFromObj(interp, objv[2], &yr) != TCL_OK
+	    || Tcl_GetIntFromObj(interp, objv[3], &mo) != TCL_OK
+	    || Tcl_GetIntFromObj(interp, objv[4], &da) != TCL_OK) {
+	return TCL_ERROR;
+    }
+    yyYear = yr; yyMonth = mo; yyDay = da;
+
+    if (TclClockFreeScan(interp, info) != TCL_OK) {
+    	return TCL_ERROR;
+    }
+
     result = Tcl_NewObj();
     resultElement = Tcl_NewObj();
     if (yyHaveDate) {
@@ -2894,9 +2834,9 @@ TclClockOldscanObjCmd(
     resultElement = Tcl_NewObj();
     if (yyHaveOrdinalMonth) {
 	Tcl_ListObjAppendElement(interp, resultElement,
-		Tcl_NewIntObj((int) yyMonthOrdinal));
+		Tcl_NewIntObj((int) yyMonthOrdinalIncr));
 	Tcl_ListObjAppendElement(interp, resultElement,
-		Tcl_NewIntObj((int) yyMonth));
+		Tcl_NewIntObj((int) yyMonthOrdinal));
     }
     Tcl_ListObjAppendElement(interp, result, resultElement);
 
diff --git a/generic/tclDictObj.c b/generic/tclDictObj.c
index 428173d..4088883 100644
--- a/generic/tclDictObj.c
+++ b/generic/tclDictObj.c
@@ -51,6 +51,8 @@ static int		DictSetCmd(ClientData dummy, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const *objv);
 static int		DictSizeCmd(ClientData dummy, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const *objv);
+static int		DictSmartRefCmd(ClientData dummy, Tcl_Interp *interp,
+			    int objc, Tcl_Obj *const *objv);
 static int		DictUnsetCmd(ClientData dummy, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const *objv);
 static int		DictUpdateCmd(ClientData dummy, Tcl_Interp *interp,
@@ -98,6 +100,7 @@ static const EnsembleImplMap implementationMap[] = {
     {"replace",	DictReplaceCmd, NULL, NULL, NULL, 0 },
     {"set",	DictSetCmd,	TclCompileDictSetCmd, NULL, NULL, 0 },
     {"size",	DictSizeCmd,	TclCompileBasic1ArgCmd, NULL, NULL, 0 },
+    {"smartref",DictSmartRefCmd,NULL, NULL, NULL, 0 },
     {"unset",	DictUnsetCmd,	TclCompileDictUnsetCmd, NULL, NULL, 0 },
     {"update",	DictUpdateCmd,	TclCompileDictUpdateCmd, NULL, NULL, 0 },
     {"values",	DictValuesCmd,	TclCompileBasic1Or2ArgCmd, NULL, NULL, 0 },
@@ -1960,6 +1963,102 @@ DictSizeCmd(
 /*
  *----------------------------------------------------------------------
  *
+ * Tcl_DictObjSmartRef --
+ *
+ *	This function returns new tcl-object with the smart reference to
+ *	dictionary object.
+ *
+ *	Object returned with this function is a smart reference (pointer),
+ *	so new object of type tclDictType, that directly references given
+ *	dictionary object (with internally increased refCount).
+ *
+ *	The usage of such pointer objects allows to hold more as one
+ *	reference to the same real dictionary object, allows to make a pointer
+ *	to part of another dictionary, allows to change the dictionary without
+ *	regarding of the "shared" state of the dictionary object.
+ *
+ *	Prevents "called with shared object" exception if object is multiple
+ *	referenced.
+ *
+ * Results:
+ *	The newly create object (contains smart reference) is returned.
+ *	The returned object has a ref count of 0.
+ *
+ * Side effects:
+ *	Increases ref count of the referenced dictionary.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Obj *
+Tcl_DictObjSmartRef(
+    Tcl_Interp *interp,
+    Tcl_Obj    *dictPtr)
+{
+    Tcl_Obj *result;
+    Dict    *dict;
+
+    if (dictPtr->typePtr != &tclDictType
+	    && SetDictFromAny(interp, dictPtr) != TCL_OK) {
+	return NULL;
+    }
+
+    dict = DICT(dictPtr);
+
+    result = Tcl_NewObj();
+    DICT(result) = dict;
+    dict->refCount++;
+    result->internalRep.twoPtrValue.ptr2 = NULL;
+    result->typePtr = &tclDictType;
+
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DictSmartRefCmd --
+ *
+ *	This function implements the "dict smartref" Tcl command.
+ *
+ *	See description of Tcl_DictObjSmartRef for details.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+DictSmartRefCmd(
+    ClientData dummy,
+    Tcl_Interp *interp,
+    int objc,
+    Tcl_Obj *const *objv)
+{
+    Tcl_Obj *result;
+
+    if (objc != 2) {
+	Tcl_WrongNumArgs(interp, 1, objv, "dictionary");
+	return TCL_ERROR;
+    }
+
+    result = Tcl_DictObjSmartRef(interp, objv[1]);
+    if (result == NULL) {
+    	return TCL_ERROR;
+    }
+
+    Tcl_SetObjResult(interp, result);
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * DictExistsCmd --
  *
  *	This function implements the "dict exists" Tcl command. See the user
diff --git a/generic/tclEnv.c b/generic/tclEnv.c
index 66ddb57..0041a40 100644
--- a/generic/tclEnv.c
+++ b/generic/tclEnv.c
@@ -17,6 +17,11 @@
 
 TCL_DECLARE_MUTEX(envMutex)	/* To serialize access to environ. */
 
+
+/* MODULE_SCOPE */
+unsigned long TclEnvEpoch = 0;	/* Epoch of the tcl environment 
+				 * (if changed with tcl-env). */
+
 static struct {
     int cacheSize;		/* Number of env strings in cache. */
     char **cache;		/* Array containing all of the environment
@@ -371,6 +376,7 @@ Tcl_PutEnv(
 	value[0] = '\0';
 	TclSetEnv(name, value+1);
     }
+    TclEnvEpoch++;
 
     Tcl_DStringFree(&nameString);
     return 0;
@@ -579,6 +585,7 @@ EnvTraceProc(
 
     if (flags & TCL_TRACE_ARRAY) {
 	TclSetupEnv(interp);
+	TclEnvEpoch++;
 	return NULL;
     }
 
@@ -599,6 +606,7 @@ EnvTraceProc(
 
 	value = Tcl_GetVar2(interp, "env", name2, TCL_GLOBAL_ONLY);
 	TclSetEnv(name2, value);
+	TclEnvEpoch++;
     }
 
     /*
@@ -622,6 +630,7 @@ EnvTraceProc(
 
     if (flags & TCL_TRACE_UNSETS) {
 	TclUnsetEnv(name2);
+	TclEnvEpoch++;
     }
     return NULL;
 }
diff --git a/generic/tclGetDate.y b/generic/tclGetDate.y
index da4c3fd..6d6a0d0 100644
--- a/generic/tclGetDate.y
+++ b/generic/tclGetDate.y
@@ -9,6 +9,7 @@
  *
  * Copyright (c) 1992-1995 Karl Lehenbauer and Mark Diekhans.
  * Copyright (c) 1995-1997 Sun Microsystems, Inc.
+ * Copyright (c) 2015 Sergey G. Brester aka sebres.
  *
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
@@ -50,73 +51,11 @@
  * parsed fields will be returned.
  */
 
-typedef struct DateInfo {
-
-    Tcl_Obj* messages;		/* Error messages */
-    const char* separatrix;	/* String separating messages */
-
-    time_t dateYear;
-    time_t dateMonth;
-    time_t dateDay;
-    int dateHaveDate;
-
-    time_t dateHour;
-    time_t dateMinutes;
-    time_t dateSeconds;
-    int dateMeridian;
-    int dateHaveTime;
-
-    time_t dateTimezone;
-    int dateDSTmode;
-    int dateHaveZone;
-
-    time_t dateRelMonth;
-    time_t dateRelDay;
-    time_t dateRelSeconds;
-    int dateHaveRel;
-
-    time_t dateMonthOrdinal;
-    int dateHaveOrdinalMonth;
-
-    time_t dateDayOrdinal;
-    time_t dateDayNumber;
-    int dateHaveDay;
-
-    const char *dateStart;
-    const char *dateInput;
-    time_t *dateRelPointer;
-
-    int dateDigitCount;
-} DateInfo;
+#include "tclDate.h"
 
 #define YYMALLOC	ckalloc
 #define YYFREE(x)	(ckfree((void*) (x)))
 
-#define yyDSTmode	(info->dateDSTmode)
-#define yyDayOrdinal	(info->dateDayOrdinal)
-#define yyDayNumber	(info->dateDayNumber)
-#define yyMonthOrdinal	(info->dateMonthOrdinal)
-#define yyHaveDate	(info->dateHaveDate)
-#define yyHaveDay	(info->dateHaveDay)
-#define yyHaveOrdinalMonth (info->dateHaveOrdinalMonth)
-#define yyHaveRel	(info->dateHaveRel)
-#define yyHaveTime	(info->dateHaveTime)
-#define yyHaveZone	(info->dateHaveZone)
-#define yyTimezone	(info->dateTimezone)
-#define yyDay		(info->dateDay)
-#define yyMonth		(info->dateMonth)
-#define yyYear		(info->dateYear)
-#define yyHour		(info->dateHour)
-#define yyMinutes	(info->dateMinutes)
-#define yySeconds	(info->dateSeconds)
-#define yyMeridian	(info->dateMeridian)
-#define yyRelMonth	(info->dateRelMonth)
-#define yyRelDay	(info->dateRelDay)
-#define yyRelSeconds	(info->dateRelSeconds)
-#define yyRelPointer	(info->dateRelPointer)
-#define yyInput		(info->dateInput)
-#define yyDigitCount	(info->dateDigitCount)
-
 #define EPOCH		1970
 #define START_OF_TIME	1902
 #define END_OF_TIME	2037
@@ -150,14 +89,6 @@ typedef enum _DSTMODE {
     DSTon, DSToff, DSTmaybe
 } DSTMODE;
 
-/*
- * Meridian: am, pm, or 24-hour style.
- */
-
-typedef enum _MERIDIAN {
-    MERam, MERpm, MER24
-} MERIDIAN;
-
 %}
 
 %union {
@@ -176,8 +107,6 @@ static int		LookupWord(YYSTYPE* yylvalPtr, char *buff);
 				     DateInfo* info, const char *s);
  static int		TclDatelex(YYSTYPE* yylvalPtr, YYLTYPE* location,
 				   DateInfo* info);
-static time_t		ToSeconds(time_t Hours, time_t Minutes,
-			    time_t Seconds, MERIDIAN Meridian);
 MODULE_SCOPE int	yyparse(DateInfo*);
 
 %}
@@ -377,12 +306,12 @@ date	: tUNUMBER '/' tUNUMBER {
 	;
 
 ordMonth: tNEXT tMONTH {
-	    yyMonthOrdinal = 1;
-	    yyMonth = $2;
+	    yyMonthOrdinalIncr = 1;
+	    yyMonthOrdinal = $2;
 	}
 	| tNEXT tUNUMBER tMONTH {
-	    yyMonthOrdinal = $2;
-	    yyMonth = $3;
+	    yyMonthOrdinalIncr = $2;
+	    yyMonthOrdinal = $3;
 	}
 	;
 
@@ -730,11 +659,11 @@ TclDateerror(
     infoPtr->separatrix = "\n";
 }
 
-static time_t
+MODULE_SCOPE int
 ToSeconds(
-    time_t Hours,
-    time_t Minutes,
-    time_t Seconds,
+    int Hours,
+    int Minutes,
+    int Seconds,
     MERIDIAN Meridian)
 {
     if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 59) {
@@ -957,65 +886,36 @@ TclDatelex(
 	} while (Count > 0);
     }
 }
-
+
 int
-TclClockOldscanObjCmd(
-    ClientData clientData,	/* Unused */
+TclClockFreeScan(
     Tcl_Interp *interp,		/* Tcl interpreter */
-    int objc,			/* Count of paraneters */
-    Tcl_Obj *const *objv)	/* Parameters */
+    DateInfo *info)		/* Input and result parameters */
 {
-    Tcl_Obj *result, *resultElement;
-    int yr, mo, da;
-    DateInfo dateInfo;
-    DateInfo* info = &dateInfo;
     int status;
 
-    if (objc != 5) {
-	Tcl_WrongNumArgs(interp, 1, objv,
-		"stringToParse baseYear baseMonth baseDay" );
-	return TCL_ERROR;
-    }
-
-    yyInput = Tcl_GetString( objv[1] );
-    dateInfo.dateStart = yyInput;
-
-    yyHaveDate = 0;
-    if (Tcl_GetIntFromObj(interp, objv[2], &yr) != TCL_OK
-	    || Tcl_GetIntFromObj(interp, objv[3], &mo) != TCL_OK
-	    || Tcl_GetIntFromObj(interp, objv[4], &da) != TCL_OK) {
-	return TCL_ERROR;
-    }
-    yyYear = yr; yyMonth = mo; yyDay = da;
-
-    yyHaveTime = 0;
-    yyHour = 0; yyMinutes = 0; yySeconds = 0; yyMeridian = MER24;
-
-    yyHaveZone = 0;
-    yyTimezone = 0; yyDSTmode = DSTmaybe;
-
-    yyHaveOrdinalMonth = 0;
-    yyMonthOrdinal = 0;
-
-    yyHaveDay = 0;
-    yyDayOrdinal = 0; yyDayNumber = 0;
+    /*
+     * yyInput = stringToParse;
+     * 
+     * ClockInitDateInfo(info) should be executed to pre-init info;
+     */
 
-    yyHaveRel = 0;
-    yyRelMonth = 0; yyRelDay = 0; yyRelSeconds = 0; yyRelPointer = NULL;
+    yyDSTmode = DSTmaybe;
 
-    dateInfo.messages = Tcl_NewObj();
-    dateInfo.separatrix = "";
-    Tcl_IncrRefCount(dateInfo.messages);
+    info->messages = Tcl_NewObj();
+    info->separatrix = "";
+    Tcl_IncrRefCount(info->messages);
 
-    status = yyparse(&dateInfo);
+    info->dateStart = yyInput;
+    status = yyparse(info);
     if (status == 1) {
-	Tcl_SetObjResult(interp, dateInfo.messages);
-	Tcl_DecrRefCount(dateInfo.messages);
+	Tcl_SetObjResult(interp, info->messages);
+	Tcl_DecrRefCount(info->messages);
 	Tcl_SetErrorCode(interp, "TCL", "VALUE", "DATE", "PARSE", NULL);
 	return TCL_ERROR;
     } else if (status == 2) {
 	Tcl_SetObjResult(interp, Tcl_NewStringObj("memory exhausted", -1));
-	Tcl_DecrRefCount(dateInfo.messages);
+	Tcl_DecrRefCount(info->messages);
 	Tcl_SetErrorCode(interp, "TCL", "MEMORY", NULL);
 	return TCL_ERROR;
     } else if (status != 0) {
@@ -1023,11 +923,11 @@ TclClockOldscanObjCmd(
 						  "from date parser. Please "
 						  "report this error as a "
 						  "bug in Tcl.", -1));
-	Tcl_DecrRefCount(dateInfo.messages);
+	Tcl_DecrRefCount(info->messages);
 	Tcl_SetErrorCode(interp, "TCL", "BUG", NULL);
 	return TCL_ERROR;
     }
-    Tcl_DecrRefCount(dateInfo.messages);
+    Tcl_DecrRefCount(info->messages);
 
     if (yyHaveDate > 1) {
 	Tcl_SetObjResult(interp,
@@ -1060,6 +960,40 @@ TclClockOldscanObjCmd(
 	return TCL_ERROR;
     }
 
+    return TCL_OK;
+}
+
+int
+TclClockOldscanObjCmd(
+    ClientData clientData,	/* Unused */
+    Tcl_Interp *interp,		/* Tcl interpreter */
+    int objc,			/* Count of paraneters */
+    Tcl_Obj *const *objv)	/* Parameters */
+{
+    Tcl_Obj *result, *resultElement;
+    int yr, mo, da;
+    DateInfo dateInfo;
+    DateInfo* info = &dateInfo;
+
+    if (objc != 5) {
+	Tcl_WrongNumArgs(interp, 1, objv,
+		"stringToParse baseYear baseMonth baseDay" );
+	return TCL_ERROR;
+    }
+
+    yyInput = Tcl_GetString( objv[1] );
+
+    if (Tcl_GetIntFromObj(interp, objv[2], &yr) != TCL_OK
+	    || Tcl_GetIntFromObj(interp, objv[3], &mo) != TCL_OK
+	    || Tcl_GetIntFromObj(interp, objv[4], &da) != TCL_OK) {
+	return TCL_ERROR;
+    }
+    yyYear = yr; yyMonth = mo; yyDay = da;
+
+    if (TclClockFreeScan(interp, info) != TCL_OK) {
+    	return TCL_ERROR;
+    }
+
     result = Tcl_NewObj();
     resultElement = Tcl_NewObj();
     if (yyHaveDate) {
@@ -1111,9 +1045,9 @@ TclClockOldscanObjCmd(
     resultElement = Tcl_NewObj();
     if (yyHaveOrdinalMonth) {
 	Tcl_ListObjAppendElement(interp, resultElement,
-		Tcl_NewIntObj((int) yyMonthOrdinal));
+		Tcl_NewIntObj((int) yyMonthOrdinalIncr));
 	Tcl_ListObjAppendElement(interp, resultElement,
-		Tcl_NewIntObj((int) yyMonth));
+		Tcl_NewIntObj((int) yyMonthOrdinal));
     }
     Tcl_ListObjAppendElement(interp, result, resultElement);
 
diff --git a/generic/tclInt.h b/generic/tclInt.h
index b369f58..ea4c73e 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -2884,6 +2884,7 @@ MODULE_SCOPE int	TclFindDictElement(Tcl_Interp *interp,
 			    const char *dict, int dictLength,
 			    const char **elementPtr, const char **nextPtr,
 			    int *sizePtr, int *literalPtr);
+MODULE_SCOPE Tcl_Obj *	Tcl_DictObjSmartRef(Tcl_Interp *interp, Tcl_Obj *);
 /* TIP #280 - Modified token based evulation, with line information. */
 MODULE_SCOPE int	TclEvalEx(Tcl_Interp *interp, const char *script,
 			    int numBytes, int flags, int line,
@@ -4873,6 +4874,13 @@ typedef struct NRE_callback {
 #define Tcl_Free(ptr)                 TclpFree(ptr)
 #endif
 
+/*
+ * Other externals.
+ */
+
+MODULE_SCOPE unsigned long TclEnvEpoch; /* Epoch of the tcl environment 
+                                         * (if changed with tcl-env). */
+
 #endif /* _TCLINT */
 
 /*