cdjpeg.h

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Hash : b56e8b28
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Date : 2022-11-08T15:01:18

Clean up the lossless JPEG feature

- Rename jpeg_simple_lossless() to jpeg_enable_lossless() and modify the
  function so that it stores the lossless parameters directly in the Ss
  and Al fields of jpeg_compress_struct rather than using a scan script.

- Move the cjpeg -lossless switch into "Switches for advanced users".

- Document the libjpeg API and run-time features that are unavailable in
  lossless mode, and ensure that all parameters, functions, and switches
  related to unavailable features are ignored or generate errors in
  lossless mode.

- Defer any action that depends on whether lossless mode is enabled
  until jpeg_start_compress()/jpeg_start_decompress() is called.

- Document the purpose of the point transform value.

- "Codec" stands for coder/decoder, so it is a bit awkward to say
  "lossless compression codec" and "lossless decompression codec".
  Use "lossless compressor" and "lossless decompressor" instead.

- Restore backward API/ABI compatibility with libjpeg v6b:

  * Move the new 'lossless' field from the exposed jpeg_compress_struct
    and jpeg_decompress_struct structures into the opaque
    jpeg_comp_master and jpeg_decomp_master structures, and allocate the
    master structures in the body of jpeg_create_compress() and
    jpeg_create_decompress().

  * Remove the new 'process' field from jpeg_compress_struct and
    jpeg_decompress_struct and replace it with the old
    'progressive_mode' field and the new 'lossless' field.

  * Remove the new 'data_unit' field from jpeg_compress_struct and
    jpeg_decompress_struct and replace it with a locally-computed
    data unit variable.

  * Restore the names of macros and fields that refer to DCT blocks, and
    document that they have a different meaning in lossless mode.  (Most
    of them aren't very meaningful in lossless mode anyhow.)

  * Remove the new alloc_darray() method from jpeg_memory_mgr and
    replace it with an internal macro that wraps the alloc_sarray()
    method.

  * Move the JDIFF* data types from jpeglib.h and jmorecfg.h into
    jpegint.h.

  * Remove the new 'codec' field from jpeg_compress_struct and
    jpeg_decompress_struct and instead reuse the existing internal
    coefficient control, forward/inverse DCT, and entropy
    encoding/decoding structures for lossless compression/decompression.

  * Repurpose existing error codes rather than introducing new ones.
    (The new JERR_BAD_RESTART and JWRN_MUST_DOWNSCALE codes remain,
    although JWRN_MUST_DOWNSCALE will probably be removed in
    libjpeg-turbo, since we have a different way of handling multiple
    data precisions.)

- Automatically enable lossless mode when a scan script with parameters
  that are only valid for lossless mode is detected, and document the
  use of scan scripts to generate lossless JPEG images.

- Move the sequential and shared Huffman routines back into jchuff.c and
  jdhuff.c, and document that those routines are shared with jclhuff.c
  and jdlhuff.c as well as with jcphuff.c and jdphuff.c.

- Move MAX_DIFF_BITS from jchuff.h into jclhuff.c, the only place where
  it is used.

- Move the predictor and scaler code into jclossls.c and jdlossls.c.

- Streamline register usage in the [un]differencers (inspired by similar
  optimizations in the color [de]converters.)

- Restructure the logic in a few places to reduce duplicated code.

- Ensure that all lossless-specific code is guarded by
  C_LOSSLESS_SUPPORTED or D_LOSSLESS_SUPPORTED and that the library can
  be built successfully if either or both of those macros is undefined.

- Remove all short forms of external names introduced by the lossless
  JPEG patch.  (These will not be needed by libjpeg-turbo, so there is
  no use cleaning them up.)

- Various wordsmithing, formatting, and punctuation tweaks

- Eliminate various compiler warnings.

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cdjpeg.h

/*
 * cdjpeg.h
 *
 * Copyright (C) 1994-1997, 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 common declarations for the sample applications
 * cjpeg and djpeg.  It is NOT used by the core JPEG library.
 */

#define JPEG_CJPEG_DJPEG	/* define proper options in jconfig.h */
#define JPEG_INTERNAL_OPTIONS	/* cjpeg.c,djpeg.c need to see xxx_SUPPORTED */
#include "jinclude.h"
#include "jpeglib.h"
#include "jerror.h"		/* get library error codes too */
#include "cderror.h"		/* get application-specific error codes */


/*
 * Object interface for cjpeg's source file decoding modules
 */

typedef struct cjpeg_source_struct * cjpeg_source_ptr;

struct cjpeg_source_struct {
  JMETHOD(void, start_input, (j_compress_ptr cinfo,
			      cjpeg_source_ptr sinfo));
  JMETHOD(JDIMENSION, get_pixel_rows, (j_compress_ptr cinfo,
				       cjpeg_source_ptr sinfo));
  JMETHOD(void, finish_input, (j_compress_ptr cinfo,
			       cjpeg_source_ptr sinfo));

  FILE *input_file;

  JSAMPARRAY buffer;
  JDIMENSION buffer_height;
};


/*
 * Object interface for djpeg's output file encoding modules
 */

typedef struct djpeg_dest_struct * djpeg_dest_ptr;

struct djpeg_dest_struct {
  /* start_output is called after jpeg_start_decompress finishes.
   * The color map will be ready at this time, if one is needed.
   */
  JMETHOD(void, start_output, (j_decompress_ptr cinfo,
			       djpeg_dest_ptr dinfo));
  /* Emit the specified number of pixel rows from the buffer. */
  JMETHOD(void, put_pixel_rows, (j_decompress_ptr cinfo,
				 djpeg_dest_ptr dinfo,
				 JDIMENSION rows_supplied));
  /* Finish up at the end of the image. */
  JMETHOD(void, finish_output, (j_decompress_ptr cinfo,
				djpeg_dest_ptr dinfo));

  /* Target file spec; filled in by djpeg.c after object is created. */
  FILE * output_file;

  /* Output pixel-row buffer.  Created by module init or start_output.
   * Width is cinfo->output_width * cinfo->output_components;
   * height is buffer_height.
   */
  JSAMPARRAY buffer;
  JDIMENSION buffer_height;
};


/*
 * cjpeg/djpeg may need to perform extra passes to convert to or from
 * the source/destination file format.  The JPEG library does not know
 * about these passes, but we'd like them to be counted by the progress
 * monitor.  We use an expanded progress monitor object to hold the
 * additional pass count.
 */

struct cdjpeg_progress_mgr {
  struct jpeg_progress_mgr pub;	/* fields known to JPEG library */
  int completed_extra_passes;	/* extra passes completed */
  int total_extra_passes;	/* total extra */
  /* last printed percentage stored here to avoid multiple printouts */
  int percent_done;
};

typedef struct cdjpeg_progress_mgr * cd_progress_ptr;


/* Short forms of external names for systems with brain-damaged linkers. */

#ifdef NEED_SHORT_EXTERNAL_NAMES
#define jinit_read_bmp		jIRdBMP
#define jinit_write_bmp		jIWrBMP
#define jinit_read_gif		jIRdGIF
#define jinit_write_gif		jIWrGIF
#define jinit_read_ppm		jIRdPPM
#define jinit_write_ppm		jIWrPPM
#define jinit_read_rle		jIRdRLE
#define jinit_write_rle		jIWrRLE
#define jinit_read_targa	jIRdTarga
#define jinit_write_targa	jIWrTarga
#define read_quant_tables	RdQTables
#define read_scan_script	RdScnScript
#define set_quant_slots		SetQSlots
#define set_sample_factors	SetSFacts
#define read_color_map		RdCMap
#define enable_signal_catcher	EnSigCatcher
#define start_progress_monitor	StProgMon
#define end_progress_monitor	EnProgMon
#define read_stdin		RdStdin
#define write_stdout		WrStdout
#endif /* NEED_SHORT_EXTERNAL_NAMES */

/* Module selection routines for I/O modules. */

EXTERN(cjpeg_source_ptr) jinit_read_bmp JPP((j_compress_ptr cinfo));
EXTERN(djpeg_dest_ptr) jinit_write_bmp JPP((j_decompress_ptr cinfo,
					    boolean is_os2));
EXTERN(cjpeg_source_ptr) jinit_read_gif JPP((j_compress_ptr cinfo));
EXTERN(djpeg_dest_ptr) jinit_write_gif JPP((j_decompress_ptr cinfo));
EXTERN(cjpeg_source_ptr) jinit_read_ppm JPP((j_compress_ptr cinfo));
EXTERN(djpeg_dest_ptr) jinit_write_ppm JPP((j_decompress_ptr cinfo));
EXTERN(cjpeg_source_ptr) jinit_read_rle JPP((j_compress_ptr cinfo));
EXTERN(djpeg_dest_ptr) jinit_write_rle JPP((j_decompress_ptr cinfo));
EXTERN(cjpeg_source_ptr) jinit_read_targa JPP((j_compress_ptr cinfo));
EXTERN(djpeg_dest_ptr) jinit_write_targa JPP((j_decompress_ptr cinfo));

/* cjpeg support routines (in rdswitch.c) */

EXTERN(boolean) read_quant_tables JPP((j_compress_ptr cinfo, char * filename,
				    int scale_factor, boolean force_baseline));
EXTERN(boolean) read_scan_script JPP((j_compress_ptr cinfo, char * filename));
EXTERN(boolean) set_quant_slots JPP((j_compress_ptr cinfo, char *arg));
EXTERN(boolean) set_sample_factors JPP((j_compress_ptr cinfo, char *arg));

/* djpeg support routines (in rdcolmap.c) */

EXTERN(void) read_color_map JPP((j_decompress_ptr cinfo, FILE * infile));

/* common support routines (in cdjpeg.c) */

EXTERN(void) enable_signal_catcher JPP((j_common_ptr cinfo));
EXTERN(void) start_progress_monitor JPP((j_common_ptr cinfo,
					 cd_progress_ptr progress));
EXTERN(void) end_progress_monitor JPP((j_common_ptr cinfo));
EXTERN(boolean) keymatch JPP((char * arg, const char * keyword, int minchars));
EXTERN(FILE *) read_stdin JPP((void));
EXTERN(FILE *) write_stdout JPP((void));

/* miscellaneous useful macros */

#ifdef DONT_USE_B_MODE		/* define mode parameters for fopen() */
#define READ_BINARY	"r"
#define WRITE_BINARY	"w"
#else
#ifdef VMS			/* VMS is very nonstandard */
#define READ_BINARY	"rb", "ctx=stm"
#define WRITE_BINARY	"wb", "ctx=stm"
#else				/* standard ANSI-compliant case */
#define READ_BINARY	"rb"
#define WRITE_BINARY	"wb"
#endif
#endif

#ifndef EXIT_FAILURE		/* define exit() codes if not provided */
#define EXIT_FAILURE  1
#endif
#ifndef EXIT_SUCCESS
#ifdef VMS
#define EXIT_SUCCESS  1		/* VMS is very nonstandard */
#else
#define EXIT_SUCCESS  0
#endif
#endif
#ifndef EXIT_WARNING
#ifdef VMS
#define EXIT_WARNING  1		/* VMS is very nonstandard */
#else
#define EXIT_WARNING  2
#endif
#endif

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kc3-lang/libjpeg-turbo/cdjpeg.h

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cdjpeg.h