/*
* tclUnixTime.c --
*
* Contains Unix specific versions of Tcl functions that obtain time
* values from the operating system.
*
* Copyright (c) 1995 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* RCS: @(#) $Id: tclUnixTime.c,v 1.25 2005/07/20 23:16:01 dkf Exp $
*/
#include "tclInt.h"
#include <locale.h>
#define TM_YEAR_BASE 1900
#define IsLeapYear(x) (((x)%4 == 0) && ((x)%100 != 0 || (x)%400 == 0))
/*
* TclpGetDate is coded to return a pointer to a 'struct tm'. For thread
* safety, this structure must be in thread-specific data. The 'tmKey'
* variable is the key to this buffer.
*/
static Tcl_ThreadDataKey tmKey;
typedef struct ThreadSpecificData {
struct tm gmtime_buf;
struct tm localtime_buf;
} ThreadSpecificData;
/*
* If we fall back on the thread-unsafe versions of gmtime and localtime, use
* this mutex to try to protect them.
*/
TCL_DECLARE_MUTEX(tmMutex)
static char *lastTZ = NULL; /* Holds the last setting of the TZ
* environment variable, or an empty string if
* the variable was not set. */
/*
* Static functions declared in this file.
*/
static void SetTZIfNecessary _ANSI_ARGS_((void));
static void CleanupMemory _ANSI_ARGS_((ClientData));
static void NativeScaleTime _ANSI_ARGS_((Tcl_Time *timebuf,
ClientData clientData));
static void NativeGetTime _ANSI_ARGS_((Tcl_Time *timebuf,
ClientData clientData));
/*
* TIP #233 (Virtualized Time): Data for the time hooks, if any.
*/
Tcl_GetTimeProc *tclGetTimeProcPtr = NativeGetTime;
Tcl_ScaleTimeProc *tclScaleTimeProcPtr = NativeScaleTime;
ClientData tclTimeClientData = NULL;
/*
*-----------------------------------------------------------------------------
*
* TclpGetSeconds --
*
* This procedure returns the number of seconds from the epoch. On most
* Unix systems the epoch is Midnight Jan 1, 1970 GMT.
*
* Results:
* Number of seconds from the epoch.
*
* Side effects:
* None.
*
*-----------------------------------------------------------------------------
*/
unsigned long
TclpGetSeconds()
{
return time((time_t *) NULL);
}
/*
*-----------------------------------------------------------------------------
*
* TclpGetClicks --
*
* This procedure returns a value that represents the highest resolution
* clock available on the system. There are no garantees on what the
* resolution will be. In Tcl we will call this value a "click". The
* start time is also system dependant.
*
* Results:
* Number of clicks from some start time.
*
* Side effects:
* None.
*
*-----------------------------------------------------------------------------
*/
unsigned long
TclpGetClicks()
{
unsigned long now;
#ifdef NO_GETTOD
if (tclGetTimeProcPtr != NativeGetTime) {
Tcl_Time time;
(*tclGetTimeProcPtr) (&time, tclTimeClientData);
now = time.sec*1000000 + time.usec;
} else {
/*
* A semi-NativeGetTime, specialized to clicks.
*/
struct tms dummy;
now = (unsigned long) times(&dummy);
}
#else
Tcl_Time time;
(*tclGetTimeProcPtr) (&time, tclTimeClientData);
now = time.sec*1000000 + time.usec;
#endif
return now;
}
/*
*----------------------------------------------------------------------
*
* TclpGetTimeZone --
*
* Determines the current timezone. The method varies wildly between
* different platform implementations, so its hidden in this function.
*
* Results:
* The return value is the local time zone, measured in minutes away from
* GMT (-ve for east, +ve for west).
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
int
TclpGetTimeZone(currentTime)
unsigned long currentTime;
{
int timeZone;
/*
* We prefer first to use the time zone in "struct tm" if the structure
* contains such a member. Following that, we try to locate the external
* 'timezone' variable and use its value. If both of those methods fail,
* we attempt to convert a known time to local time and use the difference
* from UTC as the local time zone. In all cases, we need to undo any
* Daylight Saving Time adjustment.
*/
#if defined(HAVE_TM_TZADJ)
#define TCL_GOT_TIMEZONE
/*
* Struct tm contains tm_tzadj - that value may be used.
*/
time_t curTime = (time_t) currentTime;
struct tm *timeDataPtr = TclpLocaltime(&curTime);
timeZone = timeDataPtr->tm_tzadj / 60;
if (timeDataPtr->tm_isdst) {
timeZone += 60;
}
#endif
#if defined(HAVE_TM_GMTOFF) && !defined (TCL_GOT_TIMEZONE)
#define TCL_GOT_TIMEZONE
/*
* Struct tm contains tm_gmtoff - that value may be used.
*/
time_t curTime = (time_t) currentTime;
struct tm *timeDataPtr = TclpLocaltime(&curTime);
timeZone = -(timeDataPtr->tm_gmtoff / 60);
if (timeDataPtr->tm_isdst) {
timeZone += 60;
}
#endif
#if defined(HAVE_TIMEZONE_VAR) && !defined(TCL_GOT_TIMEZONE) && !defined(USE_DELTA_FOR_TZ)
#define TCL_GOT_TIMEZONE
/*
* The 'timezone' external var is present and may be used.
*/
SetTZIfNecessary();
/*
* Note: this is not a typo in "timezone" below! See tzset documentation
* for details.
*/
timeZone = timezone / 60;
#endif
#if !defined(TCL_GOT_TIMEZONE)
#define TCL_GOT_TIMEZONE
/*
* Fallback - determine time zone with a known reference time.
*/
time_t tt;
struct tm *stm;
tt = 849268800L; /* 1996-11-29 12:00:00 GMT */
stm = TclpLocaltime(&tt); /* eg 1996-11-29 6:00:00 CST6CDT */
/*
* The calculation below assumes a max of +12 or -12 hours from GMT.
*/
timeZone = (12 - stm->tm_hour)*60 + (0 - stm->tm_min);
if (stm->tm_isdst) {
timeZone += 60;
}
/*
* Now have offset for our known reference time, eg +360 for CST6CDT.
*/
#endif
#ifndef TCL_GOT_TIMEZONE
/*
* Cause fatal compile error, we don't know how to get timezone.
*/
#error autoconf did not figure out how to determine the timezone.
#endif
return timeZone;
}
/*
*----------------------------------------------------------------------
*
* Tcl_GetTime --
*
* Gets the current system time in seconds and microseconds since the
* beginning of the epoch: 00:00 UCT, January 1, 1970.
*
* This function is hooked, allowing users to specify their own virtual
* system time.
*
* Results:
* Returns the current time in timePtr.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
Tcl_GetTime(timePtr)
Tcl_Time *timePtr; /* Location to store time information. */
{
(*tclGetTimeProcPtr) (timePtr, tclTimeClientData);
}
/*
*----------------------------------------------------------------------
*
* TclpGetDate --
*
* This function converts between seconds and struct tm. If useGMT is
* true, then the returned date will be in Greenwich Mean Time (GMT).
* Otherwise, it will be in the local time zone.
*
* Results:
* Returns a static tm structure.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
struct tm *
TclpGetDate(time, useGMT)
CONST time_t *time;
int useGMT;
{
if (useGMT) {
return TclpGmtime(time);
} else {
return TclpLocaltime(time);
}
}
/*
*----------------------------------------------------------------------
*
* TclpGmtime --
*
* Wrapper around the 'gmtime' library function to make it thread
* safe.
*
* Results:
* Returns a pointer to a 'struct tm' in thread-specific data.
*
* Side effects:
* Invokes gmtime or gmtime_r as appropriate.
*
*----------------------------------------------------------------------
*/
struct tm *
TclpGmtime(timePtr)
CONST time_t *timePtr; /* Pointer to the number of seconds since the
* local system's epoch */
{
/*
* Get a thread-local buffer to hold the returned time.
*/
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&tmKey);
#ifdef HAVE_GMTIME_R
gmtime_r(timePtr, &(tsdPtr->gmtime_buf));
#else
Tcl_MutexLock(&tmMutex);
memcpy((VOID *) &(tsdPtr->gmtime_buf), (VOID *) gmtime(timePtr),
sizeof(struct tm));
Tcl_MutexUnlock(&tmMutex);
#endif
return &(tsdPtr->gmtime_buf);
}
/*
* Forwarder for obsolete item in Stubs
*/
struct tm*
TclpGmtime_unix(timePtr)
CONST time_t *timePtr;
{
return TclpGmtime(timePtr);
}
/*
*----------------------------------------------------------------------
*
* TclpLocaltime --
*
* Wrapper around the 'localtime' library function to make it thread
* safe.
*
* Results:
* Returns a pointer to a 'struct tm' in thread-specific data.
*
* Side effects:
* Invokes localtime or localtime_r as appropriate.
*
*----------------------------------------------------------------------
*/
struct tm *
TclpLocaltime(timePtr)
CONST time_t *timePtr; /* Pointer to the number of seconds since the
* local system's epoch */
{
/*
* Get a thread-local buffer to hold the returned time.
*/
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&tmKey);
SetTZIfNecessary();
#ifdef HAVE_LOCALTIME_R
localtime_r(timePtr, &(tsdPtr->localtime_buf));
#else
Tcl_MutexLock(&tmMutex);
memcpy((VOID *) &(tsdPtr->localtime_buf), (VOID *) localtime(timePtr),
sizeof(struct tm));
Tcl_MutexUnlock(&tmMutex);
#endif
return &(tsdPtr->localtime_buf);
}
/*
* Forwarder for obsolete item in Stubs
*/
struct tm*
TclpLocaltime_unix(timePtr)
CONST time_t *timePtr;
{
return TclpLocaltime(timePtr);
}
/*
*----------------------------------------------------------------------
*
* Tcl_SetTimeProc --
*
* TIP #233 (Virtualized Time): Registers two handlers for the
* virtualization of Tcl's access to time information.
*
* Results:
* None.
*
* Side effects:
* Remembers the handlers, alters core behaviour.
*
*----------------------------------------------------------------------
*/
void
Tcl_SetTimeProc(getProc, scaleProc, clientData)
Tcl_GetTimeProc *getProc;
Tcl_ScaleTimeProc *scaleProc;
ClientData clientData;
{
tclGetTimeProcPtr = getProc;
tclScaleTimeProcPtr = scaleProc;
tclTimeClientData = clientData;
}
/*
*----------------------------------------------------------------------
*
* Tcl_QueryTimeProc --
*
* TIP #233 (Virtualized Time): Query which time handlers are registered.
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
Tcl_QueryTimeProc(getProc, scaleProc, clientData)
Tcl_GetTimeProc **getProc;
Tcl_ScaleTimeProc **scaleProc;
ClientData *clientData;
{
if (getProc) {
*getProc = tclGetTimeProcPtr;
}
if (scaleProc) {
*scaleProc = tclScaleTimeProcPtr;
}
if (clientData) {
*clientData = tclTimeClientData;
}
}
/*
*----------------------------------------------------------------------
*
* NativeScaleTime --
*
* TIP #233: Scale from virtual time to the real-time. For native scaling
* the relationship is 1:1 and nothing has to be done.
*
* Results:
* Scales the time in timePtr.
*
* Side effects:
* See above.
*
*----------------------------------------------------------------------
*/
static void
NativeScaleTime(timePtr, clientData)
Tcl_Time *timePtr;
ClientData clientData;
{
/* Native scale is 1:1. Nothing is done */
}
/*
*----------------------------------------------------------------------
*
* NativeGetTime --
*
* TIP #233: Gets the current system time in seconds and microseconds
* since the beginning of the epoch: 00:00 UCT, January 1, 1970.
*
* Results:
* Returns the current time in timePtr.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static void
NativeGetTime(timePtr, clientData)
Tcl_Time *timePtr;
ClientData clientData;
{
struct timeval tv;
struct timezone tz;
(void) gettimeofday(&tv, &tz);
timePtr->sec = tv.tv_sec;
timePtr->usec = tv.tv_usec;
}
/*
*----------------------------------------------------------------------
*
* SetTZIfNecessary --
*
* Determines whether a call to 'tzset' is needed prior to the next call
* to 'localtime' or examination of the 'timezone' variable.
*
* Results:
* None.
*
* Side effects:
* If 'tzset' has never been called in the current process, or if the
* value of the environment variable TZ has changed since the last call
* to 'tzset', then 'tzset' is called again.
*
*----------------------------------------------------------------------
*/
static void
SetTZIfNecessary()
{
CONST char *newTZ = getenv("TZ");
Tcl_MutexLock(&tmMutex);
if (newTZ == NULL) {
newTZ = "";
}
if (lastTZ == NULL || strcmp(lastTZ, newTZ)) {
tzset();
if (lastTZ == NULL) {
Tcl_CreateExitHandler(CleanupMemory, (ClientData) NULL);
} else {
Tcl_Free(lastTZ);
}
lastTZ = Tcl_Alloc(strlen(newTZ) + 1);
strcpy(lastTZ, newTZ);
}
Tcl_MutexUnlock(&tmMutex);
}
/*
*----------------------------------------------------------------------
*
* CleanupMemory --
*
* Releases the private copy of the TZ environment variable upon exit
* from Tcl.
*
* Results:
* None.
*
* Side effects:
* Frees allocated memory.
*
*----------------------------------------------------------------------
*/
static void
CleanupMemory(ClientData ignored)
{
Tcl_Free(lastTZ);
}
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/