harbour-core/harbour/contrib/hbgt/bitflags.c

/*
 * $Id$
 */

/*
 * File......: BITFLAGS.C
 * Author....: Dave Pearson
 * BBS.......: The Dark Knight Returns
 * Net/Node..: 050/069
 * User Name.: Dave Pearson
 * Date......: 31/03/93
 * Revision..: 1.0
 *
 * This is an original work by Dave Pearson and is placed in the public
 * domain.
 * 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.
 *
 * Modification history:
 * ---------------------
 *
 * 8/19/2001 Modifications for Harbour by Brian Hays, also placed in
 * the public domain.
 *
 */


#include "hbapi.h"

#define _GT_MAX(x,y)    (x > y ? x : y)

HB_FUNC( GT_NEWFLAG )
{
        char     *FlagString;
        unsigned ByteCount;
        unsigned FlagCount   = 1;
        unsigned Byte;

        if (ISNUM(1))
        {
              FlagCount = (unsigned) hb_parni(1);
        }
        if (FlagCount > 0)
        {
                ByteCount = (unsigned)((FlagCount / 8) + 1);
                if (!(FlagCount % 8))
                {
                        --ByteCount;
                }
                FlagString = hb_xgrab(ByteCount);
                for (Byte = 0; Byte < ByteCount; Byte++)
                {
                        FlagString[Byte] = 0;
                }
                hb_retclen(FlagString, ByteCount);
                hb_xfree(FlagString);
        }
        else
        {
                hb_retc(NULL);
        }
}

HB_FUNC( GT_SETFLAG )
{
        char     *FlagString;
        unsigned StartBit    = 1;
        unsigned EndBit      = 1;
        unsigned BitCount;
        unsigned BitPointer;
        unsigned BytePointer;

        if ( HB_ISCHAR(1) )
        {
                FlagString = hb_parc(1);
                if ( HB_ISNUM(2) )
                {
                        StartBit = hb_parni(2);
                }
                if ( HB_ISNUM(3) )
                {
                        EndBit = hb_parni(3);
                }
                EndBit = _GT_MAX(StartBit, EndBit);
                if (StartBit > 0 && EndBit <= (hb_parclen(1) * 8))
                {
                        for (BitCount = StartBit; BitCount <= EndBit; BitCount++)
                        {
                                BitPointer  = BitCount % 8;
                                BytePointer = (unsigned) (BitCount / 8);
                                if (!BitPointer)
                                {
                                        BitPointer = 8;
                                        --BytePointer;
                                }
                                FlagString[BytePointer] |= 1 << (BitPointer - 1);
                        }
                }
                hb_retclen(FlagString, hb_parclen(1));
        }
        else
        {
                hb_retc(NULL);
        }
}

HB_FUNC( GT_CLRFLAG )
{
        char     *FlagString;
        unsigned StartBit    = 1;
        unsigned EndBit      = 1;
        unsigned BitCount;
        unsigned BitPointer;
        unsigned BytePointer;

        if ( HB_ISCHAR(1) )
        {
                FlagString = hb_parc(1);
                if ( HB_ISNUM(2) )
                {
                        StartBit = hb_parni(2);
                }
                if ( HB_ISNUM(3) )
                {
                        EndBit = hb_parni(3);
                }
                EndBit = _GT_MAX(StartBit, EndBit);
                if (StartBit > 0 && EndBit <= (hb_parclen(1) * 8))
                {
                        for (BitCount = StartBit; BitCount <= EndBit; BitCount++)
                        {
                                BitPointer  = BitCount % 8;
                                BytePointer = (unsigned) (BitCount / 8);
                                if (!BitPointer)
                                {
                                        BitPointer = 8;
                                        --BytePointer;
                                }
                                FlagString[BytePointer] &= 0xff - (1 << (BitPointer - 1));
                        }
                }
                hb_retclen(FlagString, hb_parclen(1));
        }
        else
        {
                hb_retc(NULL);
        }
}

HB_FUNC( GT_ISFLAG  )
{

        BOOL            FlagStatus = FALSE;
        unsigned        Bit        = 1;
        unsigned        BitPointer;
        unsigned        BytePointer;
        char            *FlagString;

        if ( HB_ISCHAR(1) )
        {
                FlagString = hb_parc(1);
                if ( HB_ISNUM(2) )
                {
                        Bit = hb_parni(2);
                }
                if (Bit > 0 && Bit <= (hb_parclen(1) * 8))
                {
                        BitPointer  = Bit % 8;
                        BytePointer = (unsigned) (Bit / 8);
                        if (!BitPointer)
                        {
                                BitPointer = 8;
                                --BytePointer;
                        }
                        FlagStatus = FlagString[BytePointer] & (1 << (BitPointer - 1));
                }
        }
        hb_retl(FlagStatus);
}