/* $Id$
 *
 * COPYRIGHT:       See COPYING in the top level directory
 * PROJECT:         ReactOS system libraries
 * FILE:            lib/kernel32/thread/tls.c
 * PURPOSE:         Thread functions
 * PROGRAMMER:      Ariadne ( ariadne@xs4all.nl)
 *                  Tls functions are modified from WINE
 * UPDATE HISTORY:
 *                  Created 01/11/98
 */

/* INCLUDES ******************************************************************/

#include <k32.h>
#define NDEBUG
#include <debug.h>

/* FUNCTIONS *****************************************************************/

/*
 * @implemented
 */
DWORD
WINAPI
TlsAlloc(VOID)
{
    ULONG Index;

    RtlAcquirePebLock();

    /* Try to get regular TEB slot. */
    Index = RtlFindClearBitsAndSet(NtCurrentPeb()->TlsBitmap, 1, 0);
    if (Index == ~0U)
    {
        /* If it fails, try to find expansion TEB slot. */
        Index = RtlFindClearBitsAndSet(NtCurrentPeb()->TlsExpansionBitmap, 1, 0);
        if (Index != ~0U)
        {
            if (NtCurrentTeb()->TlsExpansionSlots == NULL)
            {
                NtCurrentTeb()->TlsExpansionSlots = HeapAlloc(GetProcessHeap(),
                                                              HEAP_ZERO_MEMORY,
                                                              TLS_EXPANSION_SLOTS *
                                                              sizeof(PVOID));
            }

            if (NtCurrentTeb()->TlsExpansionSlots == NULL)
            {
                RtlClearBits(NtCurrentPeb()->TlsExpansionBitmap, Index, 1);
                Index = ~0;
                SetLastError(ERROR_NOT_ENOUGH_MEMORY);
            }
            else
            {
                /* Clear the value. */
                NtCurrentTeb()->TlsExpansionSlots[Index] = 0;
                Index += TLS_MINIMUM_AVAILABLE;
            }
        }
        else
        {
            SetLastError(ERROR_NO_MORE_ITEMS);
        }
    }
    else
    {
        /* Clear the value. */
        NtCurrentTeb()->TlsSlots[Index] = 0;
    }

    RtlReleasePebLock();

    return Index;
}

/*
 * @implemented
 */
BOOL
WINAPI
TlsFree(DWORD Index)
{
    BOOL BitSet;

    if (Index >= TLS_EXPANSION_SLOTS + TLS_MINIMUM_AVAILABLE)
    {
        SetLastErrorByStatus(STATUS_INVALID_PARAMETER);
        return FALSE;
    }

    RtlAcquirePebLock();

    if (Index >= TLS_MINIMUM_AVAILABLE)
    {
        BitSet = RtlAreBitsSet(NtCurrentPeb()->TlsExpansionBitmap,
                               Index - TLS_MINIMUM_AVAILABLE,
                               1);

       if (BitSet)
           RtlClearBits(NtCurrentPeb()->TlsExpansionBitmap,
                        Index - TLS_MINIMUM_AVAILABLE,
                        1);
    }
    else
    {
        BitSet = RtlAreBitsSet(NtCurrentPeb()->TlsBitmap, Index, 1);
        if (BitSet)
            RtlClearBits(NtCurrentPeb()->TlsBitmap, Index, 1);
    }

    if (BitSet)
    {
        /* Clear the TLS cells (slots) in all threads of the current process. */
        NtSetInformationThread(NtCurrentThread(),
                               ThreadZeroTlsCell,
                               &Index,
                               sizeof(DWORD));
    }
    else
    {
        SetLastError(ERROR_INVALID_PARAMETER);
    }

    RtlReleasePebLock();

    return BitSet;
}

/*
 * @implemented
 */
LPVOID
WINAPI
TlsGetValue(DWORD Index)
{
    if (Index >= TLS_EXPANSION_SLOTS + TLS_MINIMUM_AVAILABLE)
    {
        SetLastErrorByStatus(STATUS_INVALID_PARAMETER);
        return NULL;
    }

    SetLastError(NO_ERROR);

    if (Index >= TLS_MINIMUM_AVAILABLE)
    {
        /* The expansion slots are allocated on demand, so check for it. */
        if (NtCurrentTeb()->TlsExpansionSlots == NULL)
            return NULL;
        return NtCurrentTeb()->TlsExpansionSlots[Index - TLS_MINIMUM_AVAILABLE];
    }
    else
    {
        return NtCurrentTeb()->TlsSlots[Index];
    }
}

/*
 * @implemented
 */
BOOL
WINAPI
TlsSetValue(DWORD Index,
            LPVOID Value)
{
    if (Index >= TLS_EXPANSION_SLOTS + TLS_MINIMUM_AVAILABLE)
    {
        SetLastErrorByStatus(STATUS_INVALID_PARAMETER);
        return FALSE;
    }

    if (Index >= TLS_MINIMUM_AVAILABLE)
    {
        if (NtCurrentTeb()->TlsExpansionSlots == NULL)
        {
            NtCurrentTeb()->TlsExpansionSlots = HeapAlloc(GetProcessHeap(),
                                                          HEAP_ZERO_MEMORY,
                                                          TLS_EXPANSION_SLOTS *
                                                          sizeof(PVOID));

            if (NtCurrentTeb()->TlsExpansionSlots == NULL)
            {
                SetLastError(ERROR_NOT_ENOUGH_MEMORY);
                return FALSE;
            }
        }

        NtCurrentTeb()->TlsExpansionSlots[Index - TLS_MINIMUM_AVAILABLE] = Value;
    }
    else
    {
        NtCurrentTeb()->TlsSlots[Index] = Value;
    }

    return TRUE;
}