%%	options

copyright owner	=	Dirk Krause
copyright year	=	2011-2014
license		=	bsd



%%	header

#ifdef __cplusplus
extern "C" {
#endif

/**	Set up resampling structure.
	This function must be called before you start
	any conversion using dk3pixre_convert().
	@param	pp	Resampling structure.
	@param	inw	Input number of bits per component.
	@param	outw	Output number of bits per component.
	@return	1 on success, 0 on error.
*/
int
dk3pixre_set(dk3_pixel_resample_t *pp, size_t inw, size_t outw);

/**	Check whether a pixel value can be converted without quality loss.
	@param	pp	Pixel resampling structure.
	@param	inval	Value to convert.
	@return	1 on success, 0 on error.
*/
int
dk3pixre_can_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval);

/**	Resample pixel. The dk3_pixel_resample_t structure must
	already be set up using dk3pixre_set().
	@param	pp	Resampling structure.
	@param	inval	Value to resample.
	@return	Pixel component resampled.
*/
dk3_bif_pixel_t
dk3pixre_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval);

/**	Get mask for maximum output value.
	@param	pp	Resampling structure.
	@return	Maximum value for given number of output bits.
*/
dk3_bif_pixel_t
dk3pixre_get_max_value(dk3_pixel_resample_t const *pp);

/**	Get one pixel component value from packed bytes.
	@param	row	Pixel data.
	@param	vi	Value index.
	@param	bpc	Number of bits per component.
	@return	Pixel component value.
*/
dk3_bif_pixel_t
dk3pixre_get_value_from_packed_bytes(
  unsigned char const	*row,
  dk3_bif_coord_t	 vi,
  size_t		 bpc
);

/**	Get maximum pixel value for a given bit width.
	@param	w	Bit width.
	@return	Maximum value on success, 0 on error.
*/
dk3_bif_pixel_t
dk3pixre_maximum_for_width(size_t w);

#ifdef __cplusplus
}
#endif

%%	module

#include "dk3all.h"
#include "dk3pixre.h"



$!trace-include



dk3_bif_pixel_t
dk3pixre_maximum_for_width(size_t w)
{
  dk3_bif_pixel_t	back	= 0;
  unsigned		val	= 1;
  size_t		i;
  for(i = 0; i < w; i++) {
    val = val * 2;
  }
  if(val) {
    val--;
    back = (dk3_bif_pixel_t)val;
#if VERSION_BEFORE_20140809
    if (((unsigned)back) != val) {
      back = 0;
    }
#else
    if (val > (unsigned)(DK3_US_MAX)) {
      back = 0;
    }
#endif
  }
  return back;
}



int
dk3pixre_set(dk3_pixel_resample_t *pp, size_t inw, size_t outw)
{
  int			back	= 0;
  dk3_bif_pixel_t	im;
  dk3_bif_pixel_t	om;

  if (pp) {
    im = dk3pixre_maximum_for_width(inw);
    om = dk3pixre_maximum_for_width(outw);
    if ((im) && (om)) {
      pp->iw = inw;
      pp->ow = outw;
      pp->im = im;
      pp->om = om;
      pp->im2 = im / 2;
      back = 1;
    }
  }
  return back;
}



#if DK3_SIZEOF_INT >= (2 * DK3_SIZEOF_BIF_PIXEL_T)

/* BEGIN unsigned */

dk3_bif_pixel_t
dk3pixre_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval)
{
  unsigned		counter;
  unsigned		res;
  unsigned		rem;
  int			ec	= 0;
  dk3_bif_pixel_t	back;
  back = inval;
  if (pp) {
    if (pp->iw != pp->ow) {
      if (1 < pp->ow) {
        counter = dk3ma_ui_mul_ok(
          (unsigned)inval,
          (unsigned)(pp->om),
          &ec
        );
        if (0 == ec) {
          if (pp->im) {
            res = counter / (unsigned)(pp->im);
	    rem = counter % (unsigned)(pp->im);
	    if (rem > ((unsigned)(pp->im2))) { res++; }
	    back = (dk3_bif_pixel_t)res;
#if VERSION_BEFORE_20140809
	    if (((unsigned)back) != res) {
	      back = 0;
	    }
#else
	    if (res > (unsigned)(DK3_US_MAX)) {
	      back = 0;
	    }
#endif
          }
        }
      } else {
        back = ((inval > pp->im2) ? 1 : 0);
      }
    }
  }
  return back;
}



int
dk3pixre_can_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval)
{
  unsigned		counter;
  unsigned		rem;
  unsigned		res;
  int			ec	= 0;
  int			back	= 0;
#if VERSION_BEFORE_20140809
  dk3_bif_pixel_t	tv;
#endif
  if (pp) {
    if (pp->iw != pp->ow) {
      if (1 < pp->ow) {
        counter = dk3ma_ui_mul_ok(
          (unsigned)inval,
	  (unsigned)(pp->om),
	  &ec
        );
        if (0 == ec) {
          if (pp->im) {
	    res = counter / (unsigned)(pp->im);
	    rem = counter % (unsigned)(pp->im);
	    if (0 == rem) {
#if VERSION_BEFORE_20140809
	      tv = (dk3_bif_pixel_t)res;
	      if (((unsigned)tv) == res) {
	        back = 1;
	      }
#else
	      if (res <= (unsigned)(DK3_US_MAX)) {
	        back = 1;
	      }
#endif
	    }
	  }
        }
      } else {
        if ((0 == inval) || (pp->im == inval)) { back = 1; }
      }
    } else {
      back = 1;
    }
  }
  return back;
}

/* END unsigned */

#else
#if DK3_SIZEOF_LONG >= (2 * DK3_SIZEOF_BIF_PIXEL_T)

/* BEGIN unsigned long */

dk3_bif_pixel_t
dk3pixre_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval)
{
  unsigned long		counter;
  unsigned long		res;
  unsigned long		rem;
  int			ec	= 0;
  dk3_bif_pixel_t	back;
  back = inval;
  if (pp) {
    if (pp->iw != pp->ow) {
      counter = dk3ma_ul_mul_ok(
        (unsigned long)inval,
        (unsigned long)(pp->om),
        &ec
      );
      if (0 == ec) {
        if (pp->im) {
          res = counter / (unsigned long)(pp->im);
	  rem = counter % (unsigned long)(pp->im);
	  if (rem > (((unsigned long)(pp->im)) / 2UL)) { res++; }
	  back = (dk3_bif_pixel_t)res;
#if VERSION_BEFORE_20140809
	  if (((unsigned long)back) != res) {
	    back = 0;
	  }
#else
	  if (res > (unsigned long)(DK3_US_MAX)) {
	    back = 0;
	  }
#endif
        }
      }
    }
  }
  return back;
}



int
dk3pixre_can_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval)
{
  unsigned long		counter;
  unsigned long		rem;
  unsigned long		res;
  int			ec	= 0;
  int			back	= 0;
#if VERSION_BEFORE_20140809
  dk3_bif_pixel_t	tv;
#endif
  if (pp) {
    if (pp->iw != pp->ow) {
      counter = dk3ma_ul_mul_ok(
        (unsigned long)inval,
	(unsigned long)(pp->om),
	&ec
      );
      if (0 == ec) {
        if (pp->im) {
	  res = counter / (unsigned long)(pp->im);
	  rem = counter % (unsigned long)(pp->im);
	  if (0 == rem) {
#if VERSION_BEFORE_20140809
	    tv = (dk3_bif_pixel_t)res;
	    if (((unsigned long)tv) == res) {
	      back = 1;
	    }
#else
	    if (res <= (unsigned long)(DK3_US_MAX)) {
	      back = 1;
	    }
#endif
	  }
	}
      }
    } else {
      back = 1;
    }
  }
  return back;
}

/* END unsigned long */

#else

/* BEGIN dk3_um_t */

dk3_bif_pixel_t
dk3pixre_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval)
{
  dk3_um_t		counter;
  dk3_um_t		res;
  dk3_um_t		rem;
  int			ec	= 0;
  dk3_bif_pixel_t	back;
  back = inval;
  if (pp) {
    if (pp->iw != pp->ow) {
      counter = dk3ma_um_mul_ok(
        (dk3_um_t)inval,
        (dk3_um_t)(pp->om),
        &ec
      );
      if (0 == ec) {
        if (pp->im) {
          res = counter / (dk3_um_t)(pp->im);
	  rem = counter % (dk3_um_t)(pp->im);
	  if (rem > (((dk3_um_t)(pp->im)) / DK3_UM_2)) { res++; }
	  back = (dk3_bif_pixel_t)res;
	  if (((dk3_um_t)back) != res) {
	    back = 0;
	  }
        }
      }
    }
  }
  return back;
}



int
dk3pixre_can_convert(dk3_pixel_resample_t const *pp, dk3_bif_pixel_t inval)
{
  dk3_um_t		counter;
  dk3_um_t		rem;
  dk3_um_t		res;
  int			ec	= 0;
  int			back	= 0;
  dk3_bif_pixel_t	tv;
  if (pp) {
    if (pp->iw != pp->ow) {
      counter = dk3ma_um_mul_ok(
        (dk3_um_t)inval,
	(dk3_um_t)(pp->om),
	&ec
      );
      if (0 == ec) {
        if (pp->im) {
	  res = counter / (dk3_um_t)(pp->im);
	  rem = counter % (dk3_um_t)(pp->im);
	  if (0 == rem) {
	    tv = (dk3_bif_pixel_t)res;
	    if (((dk3_um_t)tv) == res) {
	      back = 1;
	    }
	  }
	}
      }
    } else {
      back = 1;
    }
  }
  return back;
}

/* END dk3_um_t */

#endif
#endif


dk3_bif_pixel_t
dk3pixre_get_value_from_packed_bytes(
  unsigned char const	*row,
  dk3_bif_coord_t	 vi,
  size_t		 bpc
)
{
  unsigned short const	*us;
  unsigned char		 uc;
  dk3_bif_coord_t	 byteindex;
  dk3_bif_coord_t	 inbyte;

  dk3_bif_pixel_t	back = (dk3_bif_pixel_t)0;
  switch(bpc) {
    case 16: {
      us = (unsigned short const *)row;
      back = us[vi];
    } break;
    case 8: {
      back =  (dk3_bif_pixel_t)(row[vi]);
      back &= 0x00FFU;
    } break;
    case 4: {
      byteindex = vi / 2L;
      inbyte    = vi % 2L;
      uc = row[byteindex];
      switch((int)inbyte) {
        case 0: {
	  uc = uc >> 4;
	} break;
      }
      back = (dk3_bif_pixel_t)uc;
      back &= 0x000FU;
    } break;
    case 2: {
      byteindex = vi / 4L;
      inbyte    = vi % 4L;
      uc = row[byteindex];
      switch((int)inbyte) {
        case 0: {
	  uc = uc >> 6;
	} break;
	case 1: {
	  uc = uc >> 4;
	} break;
	case 2: {
	  uc = uc >> 2;
	} break;
      }
      back = (dk3_bif_pixel_t)uc;
      back &= 0x0003U;
    } break;
    case 1: {
      byteindex = vi / 8L;
      inbyte    = vi % 8L;
      uc = row[byteindex];
      switch((int)inbyte) {
        case 0: { uc = uc >> 7; } break;
	case 1: { uc = uc >> 6; } break;
	case 2: { uc = uc >> 5; } break;
	case 3: { uc = uc >> 4; } break;
	case 4: { uc = uc >> 3; } break;
	case 5: { uc = uc >> 2; } break;
	case 6: { uc = uc >> 1; } break;
      }
      back = (dk3_bif_pixel_t)uc;
      back &= 0x0001U;
    } break;
  }
  return back;
}



dk3_bif_pixel_t
dk3pixre_get_max_value(dk3_pixel_resample_t const *pp)
{
  dk3_bif_pixel_t back = (dk3_bif_pixel_t)0U;
  if(pp) {
    back = pp->om;
  }
  return back;
}