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+/*
+ * 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.
+ */
+
+#include "tclInt.h"
+#include <locale.h>
+#if defined(TCL_WIDE_CLICKS) && defined(MAC_OSX_TCL)
+#include <mach/mach_time.h>
+#endif
+
+/*
+ * 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(void);
+static void CleanupMemory(ClientData clientData);
+static void NativeScaleTime(Tcl_Time *timebuf,
+ ClientData clientData);
+static void NativeGetTime(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(void)
+{
+ return time(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(void)
+{
+ 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;
+}
+#ifdef TCL_WIDE_CLICKS
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpGetWideClicks --
+ *
+ * This procedure returns a WideInt 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 WideInt clicks from some start time.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_WideInt
+TclpGetWideClicks(void)
+{
+ Tcl_WideInt now;
+
+ if (tclGetTimeProcPtr != NativeGetTime) {
+ Tcl_Time time;
+
+ tclGetTimeProcPtr(&time, tclTimeClientData);
+ now = ((Tcl_WideInt)time.sec)*1000000 + time.usec;
+ } else {
+#ifdef MAC_OSX_TCL
+ now = (Tcl_WideInt) (mach_absolute_time() & INT64_MAX);
+#else
+#error Wide high-resolution clicks not implemented on this platform
+#endif
+ }
+
+ return now;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpWideClicksToNanoseconds --
+ *
+ * This procedure converts click values from the TclpGetWideClicks native
+ * resolution to nanosecond resolution.
+ *
+ * Results:
+ * Number of nanoseconds from some start time.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+double
+TclpWideClicksToNanoseconds(
+ Tcl_WideInt clicks)
+{
+ double nsec;
+
+ if (tclGetTimeProcPtr != NativeGetTime) {
+ nsec = clicks * 1000;
+ } else {
+#ifdef MAC_OSX_TCL
+ static mach_timebase_info_data_t tb;
+ static uint64_t maxClicksForUInt64;
+
+ if (!tb.denom) {
+ mach_timebase_info(&tb);
+ maxClicksForUInt64 = UINT64_MAX / tb.numer;
+ }
+ if ((uint64_t) clicks < maxClicksForUInt64) {
+ nsec = ((uint64_t) clicks) * tb.numer / tb.denom;
+ } else {
+ nsec = ((long double) (uint64_t) clicks) * tb.numer / tb.denom;
+ }
+#else
+#error Wide high-resolution clicks not implemented on this platform
+#endif
+ }
+
+ return nsec;
+}
+#endif /* TCL_WIDE_CLICKS */
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * 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(
+ 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(
+ 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(
+ 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(&tsdPtr->gmtime_buf, gmtime(timePtr), sizeof(struct tm));
+ Tcl_MutexUnlock(&tmMutex);
+#endif
+
+ return &tsdPtr->gmtime_buf;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * 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(
+ 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(&tsdPtr->localtime_buf, localtime(timePtr), sizeof(struct tm));
+ Tcl_MutexUnlock(&tmMutex);
+#endif
+
+ return &tsdPtr->localtime_buf;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * 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(
+ 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(
+ 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(
+ 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(
+ Tcl_Time *timePtr,
+ ClientData clientData)
+{
+ struct timeval tv;
+
+ (void) gettimeofday(&tv, NULL);
+ 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(void)
+{
+ 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, NULL);
+ } else {
+ ckfree(lastTZ);
+ }
+ lastTZ = ckalloc(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)
+{
+ ckfree(lastTZ);
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */