windows-nt/Source/XPSP1/NT/com/rpc/runtime/mtrt/uuidsup.cxx
2020-09-26 16:20:57 +08:00

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/*++
Copyright (C) Microsoft Corporation, 1994 - 1999
Module Name:
uuidsup.cxx
Abstract:
Implements system dependent functions used in creating Uuids.
This file is for Win32 (NT and Chicago) systems.
External functions are:
UuidGlobalMutexRequest
UuidGlobalMutexClear
GetNodeId
UuidGetValues
Note:
WARNING:
Everything in this file is only called from within UuidCreate()
which is already holding the global mutex. Therefore none of
this code is multithread safe. For example, access to the global
Uuid HKEY's is not protected.
Author:
Mario Goertzel (MarioGo) May 23, 1994
Revision History:
--*/
#include <precomp.hxx>
#include <uuidsup.hxx>
RPC_STATUS __RPC_API
UuidGetValues(
OUT UUID_CACHED_VALUES_STRUCT __RPC_FAR *Values
)
/*++
Routine Description:
This routine allocates a block of uuids for UuidCreate to handout.
Arguments:
Values - Set to contain everything needed to allocate a block of uuids.
The following fields will be updated here:
NextTimeLow - Together with LastTimeLow, this denotes the boundaries
of a block of Uuids. The values between NextTimeLow
and LastTimeLow are used in a sequence of Uuids returned
by UuidCreate().
LastTimeLow - See NextTimeLow.
ClockSequence - Clock sequence field in the uuid. This is changed
when the clock is set backward.
Return Value:
RPC_S_OK - We successfully allocated a block of uuids.
RPC_S_OUT_OF_MEMORY - As needed.
--*/
{
NTSTATUS NtStatus;
ULARGE_INTEGER Time;
ULONG Range;
ULONG Sequence;
int Tries = 0;
do {
NtStatus = NtAllocateUuids(&Time, &Range, &Sequence, (char *) &Values->NodeId[0]);
if (NtStatus == STATUS_RETRY)
{
Sleep(1);
}
Tries++;
if (Tries == 20)
{
#ifdef DEBUGRPC
PrintToDebugger("Rpc: NtAllocateUuids retried 20 times!\n");
ASSERT(Tries < 20);
#endif
NtStatus = STATUS_UNSUCCESSFUL;
}
} while(NtStatus == STATUS_RETRY);
if (!NT_SUCCESS(NtStatus))
{
return(RPC_S_OUT_OF_MEMORY);
}
// NtAllocateUuids keeps time in SYSTEM_TIME format which is 100ns ticks since
// Jan 1, 1601. UUIDs use time in 100ns ticks since Oct 15, 1582.
// 17 Days in Oct + 30 (Nov) + 31 (Dec) + 18 years and 5 leap days.
Time.QuadPart += (unsigned __int64) (1000*1000*10) // seconds
* (unsigned __int64) (60 * 60 * 24) // days
* (unsigned __int64) (17+30+31+365*18+5); // # of days
ASSERT(Range);
Values->ClockSeqHiAndReserved =
RPC_UUID_RESERVED | (((unsigned char) (Sequence >> 8))
& (unsigned char) RPC_UUID_CLOCK_SEQ_HI_MASK);
Values->ClockSeqLow = (unsigned char) (Sequence & 0x00FF);
// The order of these assignments is important
Values->Time.QuadPart = Time.QuadPart + (Range - 1);
Values->AllocatedCount = Range;
if ((Values->NodeId[0] & 0x80) == 0)
{
return(RPC_S_OK);
}
return (RPC_S_UUID_LOCAL_ONLY);
}