FreeRTOS/FreeRTOS-Plus/Source/Reliance-Edge/util/bitmap.c

/*             ----> DO NOT REMOVE THE FOLLOWING NOTICE <----
 *
 *                 Copyright (c) 2014-2015 Datalight, Inc.
 *                     All Rights Reserved Worldwide.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; use version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but "AS-IS," WITHOUT ANY WARRANTY; without even the implied warranty
 *  of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/*  Businesses and individuals that for commercial or other reasons cannot
 *  comply with the terms of the GPLv2 license may obtain a commercial license
 *  before incorporating Reliance Edge into proprietary software for
 *  distribution in any form.  Visit http://www.datalight.com/reliance-edge for
 *  more information.
 */

/** @file
 *  @brief Implements utilities for working with bitmaps.
 */
#include <redfs.h>


/** @brief Query the state of a bit in a bitmap.
 *
 *  Bits are counted from most significant to least significant.  Thus, the mask
 *  for bit zero is 0x80 applied to the first byte in the bitmap.
 *
 *  @param pbBitmap Pointer to the bitmap.
 *  @param ulBit    The bit to query.
 *
 *  @retval Whether the bit is set (true) or clear (false.
 */
bool RedBitGet( const uint8_t * pbBitmap,
                uint32_t ulBit )
{
    bool fRet;

    if( pbBitmap == NULL )
    {
        REDERROR();
        fRet = false;
    }
    else
    {
        fRet = ( pbBitmap[ ulBit >> 3U ] & ( 0x80U >> ( ulBit & 7U ) ) ) != 0U;
    }

    return fRet;
}


/** @brief Set a bit in a bitmap to one.
 *
 *  Bits are counted from most significant to least significant.  Thus, the mask
 *  for bit zero is 0x80 applied to the first byte in the bitmap.
 *
 *  @param pbBitmap Pointer to the bitmap.
 *  @param ulBit    The bit to set.
 */
void RedBitSet( uint8_t * pbBitmap,
                uint32_t ulBit )
{
    REDASSERT( pbBitmap != NULL );

    if( pbBitmap != NULL )
    {
        pbBitmap[ ulBit >> 3U ] |= ( 0x80U >> ( ulBit & 7U ) );
    }
}


/** @brief Clear a bit in a bitmap to zero.
 *
 *  Bits are counted from most significant to least significant.  Thus, the mask
 *  for bit zero is 0x80 applied to the first byte in the bitmap.
 *
 *  @param pbBitmap Pointer to the bitmap.
 *  @param ulBit    The bit to clear.
 */
void RedBitClear( uint8_t * pbBitmap,
                  uint32_t ulBit )
{
    REDASSERT( pbBitmap != NULL );

    if( pbBitmap != NULL )
    {
        pbBitmap[ ulBit >> 3U ] &= ~( 0x80U >> ( ulBit & 7U ) );
    }
}