jlossls.h

/*
 * jlossls.h
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1998, Thomas G. Lane.
 * Lossless JPEG Modifications:
 * Copyright (C) 1999, Ken Murchison.
 * Copyright (C) 2022, D. R. Commander.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This include file contains common declarations for the lossless JPEG
 * codec modules.
 */

#ifndef JLOSSLS_H
#define JLOSSLS_H

#if defined(C_LOSSLESS_SUPPORTED) || defined(D_LOSSLESS_SUPPORTED)

#define JPEG_INTERNALS
#include "jpeglib.h"


#define ALLOC_DARRAY(pool_id, diffsperrow, numrows) \
  (JDIFFARRAY)(*cinfo->mem->alloc_sarray) \
    ((j_common_ptr) cinfo, pool_id, \
     (diffsperrow) * sizeof(JDIFF) / sizeof(JSAMPLE), numrows)


/*
 * Table H.1: Predictors for lossless coding.
 */

#define PREDICTOR1	Ra
#define PREDICTOR2	Rb
#define PREDICTOR3	Rc
#define PREDICTOR4	(int) ((INT32) Ra + (INT32) Rb - (INT32) Rc)
#define PREDICTOR5	(int) ((INT32) Ra + RIGHT_SHIFT((INT32) Rb - (INT32) Rc, 1))
#define PREDICTOR6	(int) ((INT32) Rb + RIGHT_SHIFT((INT32) Ra - (INT32) Rc, 1))
#define PREDICTOR7	(int) RIGHT_SHIFT((INT32) Ra + (INT32) Rb, 1)

#endif


#ifdef C_LOSSLESS_SUPPORTED

typedef JMETHOD(void, predict_difference_method_ptr,
		(j_compress_ptr cinfo, int ci,
		 JSAMPROW input_buf, JSAMPROW prev_row,
		 JDIFFROW diff_buf, JDIMENSION width));

/* Lossless compressor */
typedef struct {
  struct jpeg_forward_dct pub;	/* public fields */

  /* It is useful to allow each component to have a separate diff method. */
  predict_difference_method_ptr predict_difference[MAX_COMPONENTS];

  /* MCU rows left in the restart interval for each component */
  unsigned int restart_rows_to_go[MAX_COMPONENTS];

  /* Sample scaling */
  JMETHOD(void, scaler_scale, (j_compress_ptr cinfo,
			       JSAMPROW input_buf, JSAMPROW output_buf,
			       JDIMENSION width));
} jpeg_lossless_compressor;

typedef jpeg_lossless_compressor * lossless_comp_ptr;

#endif /* C_LOSSLESS_SUPPORTED */


#ifdef D_LOSSLESS_SUPPORTED

typedef JMETHOD(void, predict_undifference_method_ptr,
		(j_decompress_ptr cinfo, int comp_index,
		 JDIFFROW diff_buf, JDIFFROW prev_row,
		 JDIFFROW undiff_buf, JDIMENSION width));

/* Lossless decompressor */
typedef struct {
  struct jpeg_inverse_dct pub;	/* public fields */

  /* It is useful to allow each component to have a separate undiff method. */
  predict_undifference_method_ptr predict_undifference[MAX_COMPONENTS];

  /* Sample scaling */
  JMETHOD(void, scaler_scale, (j_decompress_ptr cinfo,
			       JDIFFROW diff_buf, JSAMPROW output_buf,
			       JDIMENSION width));

  int scale_factor;

} jpeg_lossless_decompressor;

typedef jpeg_lossless_decompressor * lossless_decomp_ptr;

#endif /* D_LOSSLESS_SUPPORTED */

#endif /* JLOSSLS_H */