/*====================================================================*

 -  Copyright (C) 2001 Leptonica.  All rights reserved.

 -

 -  Redistribution and use in source and binary forms, with or without

 -  modification, are permitted provided that the following conditions

 -  are met:

 -  1. Redistributions of source code must retain the above copyright

 -     notice, this list of conditions and the following disclaimer.

 -  2. Redistributions in binary form must reproduce the above

 -     copyright notice, this list of conditions and the following

 -     disclaimer in the documentation and/or other materials

 -     provided with the distribution.

 -

 -  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 -  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 -  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 -  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ANY

 -  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 -  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 -  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 -  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 -  OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 -  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 -  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *====================================================================*/

/*!

 * \file arrayaccess.c

 * <pre>

 *

 *     Access within an array of 32-bit words

 *

 *           l_int32     l_getDataBit()

 *           void        l_setDataBit()

 *           void        l_clearDataBit()

 *           void        l_setDataBitVal()

 *           l_int32     l_getDataDibit()

 *           void        l_setDataDibit()

 *           void        l_clearDataDibit()

 *           l_int32     l_getDataQbit()

 *           void        l_setDataQbit()

 *           void        l_clearDataQbit()

 *           l_int32     l_getDataByte()

 *           void        l_setDataByte()

 *           l_int32     l_getDataTwoBytes()

 *           void        l_setDataTwoBytes()

 *           l_int32     l_getDataFourBytes()

 *           void        l_setDataFourBytes()

 *

 *     Note that these all require 32-bit alignment, and hence an input

 *     ptr to l_uint32.  However, this is not enforced by the compiler.

 *     Instead, we allow the use of a void* ptr, because the line ptrs

 *     are an efficient way to get random access (see pixGetLinePtrs()).

 *     It is then necessary to cast internally within each function

 *     because ptr arithmetic requires knowing the size of the units

 *     being referenced.

 * </pre>

 */

#ifdef HAVE_CONFIG_H

#include <config_auto.h>

#endif  /* HAVE_CONFIG_H */

#include "allheaders.h"

/*----------------------------------------------------------------------*

 *                 Access within an array of 32-bit words               *

 *----------------------------------------------------------------------*/

/*!

 * \brief   l_getDataBit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  val of the nth 1-bit pixel.

 */

l_int32

l_getDataBit(const void *line,

             l_int32     n)

{

    return (*((const l_uint32 *)line + (n >> 5)) >> (31 - (n & 31))) & 1;

}

/*!

 * \brief   l_setDataBit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  void

 *

 *  Action: sets the pixel to 1

 */

void

l_setDataBit(void    *line,

             l_int32  n)

{

    *((l_uint32 *)line + (n >> 5)) |= (0x80000000 >> (n & 31));

}

/*!

 * \brief   l_clearDataBit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  void

 *

 *  Action: sets the 1-bit pixel to 0

 */

void

l_clearDataBit(void    *line,

               l_int32  n)

{

    *((l_uint32 *)line + (n >> 5)) &= ~(0x80000000 >> (n & 31));

}

/*!

 * \brief   l_setDataBitVal()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \param[in]    val   val to be inserted: 0 or 1

 * \return  void

 *

 * <pre>

 * Notes:

 *      (1) This is an accessor for a 1 bpp pix.

 *      (2) It is actually a little slower than using:

 *            if (val == 0)

 *                l_ClearDataBit(line, n);

 *            else

 *                l_SetDataBit(line, n);

 * </pre>

 */

void

l_setDataBitVal(void    *line,

                l_int32  n,

                l_int32  val)

{

l_uint32    *pword;

    pword = (l_uint32 *)line + (n >> 5);

    *pword &= ~(0x80000000 >> (n & 31));  /* clear */

    *pword |= (l_uint32)val << (31 - (n & 31));   /* set */

}

/*!

 * \brief   l_getDataDibit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  val of the nth 2-bit pixel.

 */

l_int32

l_getDataDibit(const void *line,

               l_int32     n)

{

    return (*((const l_uint32 *)line + (n >> 4)) >> (2 * (15 - (n & 15)))) & 3;

}

/*!

 * \brief   l_setDataDibit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \param[in]    val   val to be inserted: 0 - 3

 * \return  void

 */

void

l_setDataDibit(void    *line,

               l_int32  n,

               l_int32  val)

{

l_uint32    *pword;

    pword = (l_uint32 *)line + (n >> 4);

    *pword &= ~(0xc0000000 >> (2 * (n & 15)));  /* clear */

    *pword |= (l_uint32)(val & 3) << (30 - 2 * (n & 15));   /* set */

}

/*!

 * \brief   l_clearDataDibit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  void

 *

 *  Action: sets the 2-bit pixel to 0

 */

void

l_clearDataDibit(void    *line,

                 l_int32  n)

{

    *((l_uint32 *)line + (n >> 4)) &= ~(0xc0000000 >> (2 * (n & 15)));

}

/*!

 * \brief   l_getDataQbit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  val of the nth 4-bit pixel.

 */

l_int32

l_getDataQbit(const void *line,

              l_int32     n)

{

    return (*((const l_uint32 *)line + (n >> 3)) >> (4 * (7 - (n & 7)))) & 0xf;

}

/*!

 * \brief   l_setDataQbit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \param[in]    val   val to be inserted: 0 - 0xf

 * \return  void

 */

void

l_setDataQbit(void    *line,

              l_int32  n,

              l_int32  val)

{

l_uint32    *pword;

    pword = (l_uint32 *)line + (n >> 3);

    *pword &= ~(0xf0000000 >> (4 * (n & 7)));  /* clear */

    *pword |= (l_uint32)(val & 15) << (28 - 4 * (n & 7));   /* set */

}

/*!

 * \brief   l_clearDataQbit()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  void

 *

 *  Action: sets the 4-bit pixel to 0

 */

void

l_clearDataQbit(void    *line,

                l_int32  n)

{

    *((l_uint32 *)line + (n >> 3)) &= ~(0xf0000000 >> (4 * (n & 7)));

}

/*!

 * \brief   l_getDataByte()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  value of the n-th byte pixel

 */

l_int32

l_getDataByte(const void *line,

              l_int32     n)

{

#ifdef  L_BIG_ENDIAN

    return *((const l_uint8 *)line + n);

#else  /* L_LITTLE_ENDIAN */

    return *(l_uint8 *)((l_uintptr_t)((const l_uint8 *)line + n) ^ 3);

#endif  /* L_BIG_ENDIAN */

}

/*!

 * \brief   l_setDataByte()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \param[in]    val   val to be inserted: 0 - 0xff

 * \return  void

 */

void

l_setDataByte(void    *line,

              l_int32  n,

              l_int32  val)

{

#ifdef  L_BIG_ENDIAN

    *((l_uint8 *)line + n) = val;

#else  /* L_LITTLE_ENDIAN */

    *(l_uint8 *)((l_uintptr_t)((l_uint8 *)line + n) ^ 3) = val;

#endif  /* L_BIG_ENDIAN */

}

/*!

 * \brief   l_getDataTwoBytes()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  value of the n-th 2-byte pixel

 */

l_int32

l_getDataTwoBytes(const void *line,

                  l_int32     n)

{

#ifdef  L_BIG_ENDIAN

    return *((const l_uint16 *)line + n);

#else  /* L_LITTLE_ENDIAN */

    return *(l_uint16 *)((l_uintptr_t)((const l_uint16 *)line + n) ^ 2);

#endif  /* L_BIG_ENDIAN */

}

/*!

 * \brief   l_setDataTwoBytes()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \param[in]    val   val to be inserted: 0 - 0xffff

 * \return  void

 */

void

l_setDataTwoBytes(void    *line,

                  l_int32  n,

                  l_int32  val)

{

#ifdef  L_BIG_ENDIAN

    *((l_uint16 *)line + n) = val;

#else  /* L_LITTLE_ENDIAN */

    *(l_uint16 *)((l_uintptr_t)((l_uint16 *)line + n) ^ 2) = val;

#endif  /* L_BIG_ENDIAN */

}

/*!

 * \brief   l_getDataFourBytes()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \return  value of the n-th 4-byte pixel

 */

l_int32

l_getDataFourBytes(const void *line,

                   l_int32     n)

{

    return *((const l_uint32 *)line + n);

}

/*!

 * \brief   l_setDataFourBytes()

 *

 * \param[in]    line  ptr to beginning of data line

 * \param[in]    n     pixel index

 * \param[in]    val   val to be inserted: 0 - 0xffffffff

 * \return  void

 */

void

l_setDataFourBytes(void    *line,

                   l_int32  n,

                   l_int32  val)

{

    *((l_uint32 *)line + n) = val;

}