/*

 * jcscale.c

 *

 * Copyright (C) 1998, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * This file contains sample downscaling by 2^Pt for lossless JPEG.

 */

#define JPEG_INTERNALS

#include "jinclude16.h"

#include "jpeglib16.h"

#include "jlossls16.h"    /* Private declarations for lossless codec */

#ifdef C_LOSSLESS_SUPPORTED

METHODDEF(void)

simple_downscale(j_compress_ptr cinfo,

     const JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)

{

  /* j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec; */

  unsigned int xindex;

  SHIFT_TEMPS

  for (xindex = 0; xindex < width; xindex++)

    output_buf[xindex] = (JSAMPLE) RIGHT_SHIFT(GETJSAMPLE(input_buf[xindex]),

                 cinfo->Al);

}

METHODDEF(void)

noscale(j_compress_ptr cinfo,

  JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)

{

  (void)cinfo;

  MEMCOPY(output_buf, input_buf, width * SIZEOF(JSAMPLE));

  return;

}

METHODDEF(void)

scaler_start_pass (j_compress_ptr cinfo)

{

  j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;

  /* Set scaler function based on Pt */

  if (cinfo->Al)

    losslsc->scaler_scale = simple_downscale;

  else

    losslsc->scaler_scale = noscale;

}

GLOBAL(void)

jinit_c_scaler (j_compress_ptr cinfo)

{

  j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;

  losslsc->scaler_start_pass = scaler_start_pass;

}

#endif /* C_LOSSLESS_SUPPORTED */