Source Code 1994 March/Source_Code_CD-ROM_Walnut_Creek_March_1994.iso/compsrcs/misc/volume29/jpeg/part09

Text File | 1992-03-23 | 53.2 KB | 1,384 lines

Newsgroups: comp.sources.misc
From: [e-mail] (Independent JPEG Group)
Subject:  v29i009:  jpeg - JPEG image compression, Part09/18
Message-ID: <[e-mail]>
X-Md4-Signature: 6cd9ed3c2c2bdfc1893b6903d1fc8f56
Date: Tue, 24 Mar 1992 14:48:04 GMT
Approved: [e-mail]

Submitted-by: [e-mail] (Independent JPEG Group)
Posting-number: Volume 29, Issue 9
Archive-name: jpeg/part09
Environment: UNIX, VMS, MS-DOS, Mac, Amiga, Cray

#! /bin/sh
# into a shell via "sh file" or similar.  To overwrite existing files,
# type "sh file -c".
# The tool that generated this appeared in the comp.sources.unix newsgroup;
# send mail to [e-mail] if you want that tool.
# Contents:  example.c jmemnobs.c jquant1.c
# Wrapped by kent@sparky on Mon Mar 23 16:02:46 1992
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
echo If this archive is complete, you will see the following message:
echo '          "shar: End of archive 9 (of 18)."'
if test -f 'example.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'example.c'\"
else
  echo shar: Extracting \"'example.c'\" \(26472 characters\)
  sed "s/^X//" >'example.c' <<'END_OF_FILE'
X/*
X * example.c
X *
X * This file is not actually part of the JPEG software.  Rather, it provides
X * a skeleton that may be useful for constructing applications that use the
X * JPEG software as subroutines.  This code will NOT do anything useful as is.
X *
X * This file illustrates how to use the JPEG code as a subroutine library
X * to read or write JPEG image files.  We assume here that you are not
X * merely interested in converting the image to yet another image file format
X * (if you are, you should be adding another I/O module to cjpeg/djpeg, not
X * constructing a new application).  Instead, we show how to pass the
X * decompressed image data into or out of routines that you provide.  For
X * example, a viewer program might use the JPEG decompressor together with
X * routines that write the decompressed image directly to a display.
X *
X * We present these routines in the same coding style used in the JPEG code
X * (ANSI function definitions, etc); but you are of course free to code your
X * routines in a different style if you prefer.
X */
X
X/*
X * Include file for declaring JPEG data structures.
X * This file also includes some system headers like <stdio.h>;
X * if you prefer, you can include "jconfig.h" and "jpegdata.h" instead.
X */
X
X#include "jinclude.h"
X
X/*
X * <setjmp.h> is used for the optional error recovery mechanism shown in
X * the second part of the example.
X */
X
X#include <setjmp.h>
X
X
X
X/******************** JPEG COMPRESSION SAMPLE INTERFACE *******************/
X
X/* This half of the example shows how to feed data into the JPEG compressor.
X * We present a minimal version that does not worry about refinements such
X * as error recovery (the JPEG code will just exit() if it gets an error).
X */
X
X
X/*
X * To supply the image data for compression, you must define three routines
X * input_init, get_input_row, and input_term.  These routines will be called
X * from the JPEG compressor via function pointer values that you store in the
X * cinfo data structure; hence they need not be globally visible and the exact
X * names don't matter.  (In fact, the "METHODDEF" macro expands to "static" if
X * you use the unmodified JPEG include files.)
X *
X * The input file reading modules (jrdppm.c, jrdgif.c, jrdtarga.c, etc) may be
X * useful examples of what these routines should actually do, although each of
X * them is encrusted with a lot of specialized code for its own file format.
X */
X
X
XMETHODDEF void
Xinput_init (compress_info_ptr cinfo)
X/* Initialize for input; return image size and component data. */
X{
X  /* This routine must return five pieces of information about the incoming
X   * image, and must do any setup needed for the get_input_row routine.
X   * The image information is returned in fields of the cinfo struct.
X   * (If you don't care about modularity, you could initialize these fields
X   * in the main JPEG calling routine, and make this routine be a no-op.)
X   * We show some example values here.
X   */
X  cinfo->image_width = 640;        /* width in pixels */
X  cinfo->image_height = 480;        /* height in pixels */
X  /* JPEG views an image as being a rectangular array of pixels, with each
X   * pixel having the same number of "component" values (color channels).
X   * You must specify how many components there are and the colorspace
X   * interpretation of the components.  Most applications will use RGB data or
X   * grayscale data.  If you want to use something else, you'll need to study
X   * and perhaps modify jcdeflts.c, jccolor.c, and jdcolor.c.
X   */
X  cinfo->input_components = 3;        /* or 1 for grayscale */
X  cinfo->in_color_space = CS_RGB;    /* or CS_GRAYSCALE for grayscale */
X  cinfo->data_precision = 8;        /* bits per pixel component value */
X  /* In the current JPEG software, data_precision must be set equal to
X   * BITS_IN_JSAMPLE, which is 8 unless you twiddle jconfig.h.  Future
X   * versions might allow you to say either 8 or 12 if compiled with
X   * 12-bit JSAMPLEs, or up to 16 in lossless mode.  In any case,
X   * it is up to you to scale incoming pixel values to the range
X   *   0 .. (1<<data_precision)-1.
X   * If your image data format is fixed at a byte per component,
X   * then saying "8" is probably the best long-term solution.
X   */
X}
X
X
X/*
X * This function is called repeatedly and must supply the next row of pixels
X * on each call.  The rows MUST be returned in top-to-bottom order if you want
X * your JPEG files to be compatible with everyone else's.  (If you cannot
X * readily read your data in that order, you'll need an intermediate array to
X * hold the image.  See jrdtarga.c or jrdrle.c for examples of handling
X * bottom-to-top source data using the JPEG code's portable mechanisms.)
X * The data is to be returned into a 2-D array of JSAMPLEs, indexed as
X *        JSAMPLE pixel_row[component][column]
X * where component runs from 0 to cinfo->input_components-1, and column runs
X * from 0 to cinfo->image_width-1 (column 0 is left edge of image).  Note that
X * this is actually an array of pointers to arrays rather than a true 2D array,
X * since C does not support variable-size multidimensional arrays.
X * JSAMPLE is typically typedef'd as "unsigned char".
X */
X
X
XMETHODDEF void
Xget_input_row (compress_info_ptr cinfo, JSAMPARRAY pixel_row)
X/* Read next row of pixels into pixel_row[][] */
X{
X  /* This example shows how you might read RGB data (3 components)
X   * from an input file in which the data is stored 3 bytes per pixel
X   * in left-to-right, top-to-bottom order.
X   */
X  register FILE * infile = cinfo->input_file;
X  register JSAMPROW ptr0, ptr1, ptr2;
X  register long col;
X
X  ptr0 = pixel_row[0];
X  ptr1 = pixel_row[1];
X  ptr2 = pixel_row[2];
X  for (col = 0; col < cinfo->image_width; col++) {
X    *ptr0++ = (JSAMPLE) getc(infile); /* red */
X    *ptr1++ = (JSAMPLE) getc(infile); /* green */
X    *ptr2++ = (JSAMPLE) getc(infile); /* blue */
X  }
X}
X
X
XMETHODDEF void
Xinput_term (compress_info_ptr cinfo)
X/* Finish up at the end of the input */
X{
X  /* This termination routine will very often have no work to do, */
X  /* but you must provide it anyway. */
X  /* Note that the JPEG code will only call it during successful exit; */
X  /* if you want it called during error exit, you gotta do that yourself. */
X}
X
X
X/*
X * That's it for the routines that deal with reading the input image data.
X * Now we have overall control and parameter selection routines.
X */
X
X
X/*
X * This routine must determine what output JPEG file format is to be written,
X * and make any other compression parameter changes that are desirable.
X * This routine gets control after the input file header has been read
X * (i.e., right after input_init has been called).  You could combine its
X * functions into input_init, or even into the main control routine, but
X * if you have several different input_init routines, it's a definite win
X * to keep this separate.  You MUST supply this routine even if it's a no-op.
X */
X
XMETHODDEF void
Xc_ui_method_selection (compress_info_ptr cinfo)
X{
X  /* If the input is gray scale, generate a monochrome JPEG file. */
X  if (cinfo->in_color_space == CS_GRAYSCALE)
X    j_monochrome_default(cinfo);
X  /* For now, always select JFIF output format. */
X  jselwjfif(cinfo);
X}
X
X
X/*
X * OK, here is the main function that actually causes everything to happen.
X * We assume here that the target filename is supplied by the caller of this
X * routine, and that all JPEG compression parameters can be default values.
X */
X
XGLOBAL void
Xwrite_JPEG_file (char * filename)
X{
X  /* These three structs contain JPEG parameters and working data.
X   * They must survive for the duration of parameter setup and one
X   * call to jpeg_compress; typically, making them local data in the
X   * calling routine is the best strategy.
X   */
X  struct compress_info_struct cinfo;
X  struct compress_methods_struct c_methods;
X  struct external_methods_struct e_methods;
X
X  /* Initialize the system-dependent method pointers. */
X  cinfo.methods = &c_methods;    /* links to method structs */
X  cinfo.emethods = &e_methods;
X  /* Here we use the default JPEG error handler, which will just print
X   * an error message on stderr and call exit().  See the second half of
X   * this file for an example of more graceful error recovery.
X   */
X  jselerror(&e_methods);    /* select std error/trace message routines */
X  /* Here we use the standard memory manager provided with the JPEG code.
X   * In some cases you might want to replace the memory manager, or at
X   * least the system-dependent part of it, with your own code.
X   */
X  jselmemmgr(&e_methods);    /* select std memory allocation routines */
X  /* If the compressor requires full-image buffers (for entropy-coding
X   * optimization or a noninterleaved JPEG file), it will create temporary
X   * files for anything that doesn't fit within the maximum-memory setting.
X   * (Note that temp files are NOT needed if you use the default parameters.)
X   * You can change the default maximum-memory setting by changing
X   * e_methods.max_memory_to_use after jselmemmgr returns.
X   * On some systems you may also need to set up a signal handler to
X   * ensure that temporary files are deleted if the program is interrupted.
X   * (This is most important if you are on MS-DOS and use the jmemdos.c
X   * memory manager back end; it will try to grab extended memory for
X   * temp files, and that space will NOT be freed automatically.)
X   * See jcmain.c or jdmain.c for an example signal handler.
X   */
X
X  /* Here, set up pointers to your own routines for input data handling
X   * and post-init parameter selection.
X   */
X  c_methods.input_init = input_init;
X  c_methods.get_input_row = get_input_row;
X  c_methods.input_term = input_term;
X  c_methods.c_ui_method_selection = c_ui_method_selection;
X
X  /* Set up default JPEG parameters in the cinfo data structure. */
X  j_c_defaults(&cinfo, 75, FALSE);
X  /* Note: 75 is the recommended default quality level; you may instead pass
X   * a user-specified quality level.  Be aware that values below 25 will cause
X   * non-baseline JPEG files to be created (and a warning message to that
X   * effect to be emitted on stderr).  This won't bother our decoder, but some
X   * commercial JPEG implementations may choke on non-baseline JPEG files.
X   * If you want to force baseline compatibility, pass TRUE instead of FALSE.
X   * (If non-baseline files are fine, but you could do without that warning
X   * message, set e_methods.trace_level to -1.)
X   */
X
X  /* At this point you can modify the default parameters set by j_c_defaults
X   * as needed.  For a minimal implementation, you shouldn't need to change
X   * anything.  See jcmain.c for some examples of what you might change.
X   */
X
X  /* Select the input and output files.
X   * Note that cinfo.input_file is only used if your input reading routines
X   * use it; otherwise, you can just make it NULL.
X   * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
X   * requires it in order to write binary files.
X   */
X
X  cinfo.input_file = NULL;    /* if no actual input file involved */
X
X  if ((cinfo.output_file = fopen(filename, "wb")) == NULL) {
X    fprintf(stderr, "can't open %s\n", filename);
X    exit(1);
X  }
X
X  /* Here we go! */
X  jpeg_compress(&cinfo);
X
X  /* That's it, son.  Nothin' else to do, except close files. */
X  /* Here we assume only the output file need be closed. */
X  fclose(cinfo.output_file);
X
X  /* Note: if you want to compress more than one image, we recommend you
X   * repeat this whole routine.  You MUST repeat the j_c_defaults()/alter
X   * parameters/jpeg_compress() sequence, as some data structures allocated
X   * in j_c_defaults are freed upon exit from jpeg_compress.
X   */
X}
X
X
X
X/******************** JPEG DECOMPRESSION SAMPLE INTERFACE *******************/
X
X/* This half of the example shows how to read data from the JPEG decompressor.
X * It's a little more refined than the above in that we show how to do your
X * own error recovery.  If you don't care about that, you don't need these
X * next two routines.
X */
X
X
X/*
X * These routines replace the default trace/error routines included with the
X * JPEG code.  The example trace_message routine shown here is actually the
X * same as the standard one, but you could modify it if you don't want messages
X * sent to stderr.  The example error_exit routine is set up to return
X * control to read_JPEG_file() rather than calling exit().  You can use the
X * same routines for both compression and decompression error recovery.
X */
X
X/* These static variables are needed by the error routines. */
Xstatic jmp_buf setjmp_buffer;    /* for return to caller */
Xstatic external_methods_ptr emethods; /* needed for access to message_parm */
X
X
X/* This routine is used for any and all trace, debug, or error printouts
X * from the JPEG code.  The parameter is a printf format string; up to 8
X * integer data values for the format string have been stored in the
X * message_parm[] field of the external_methods struct.
X */
X
XMETHODDEF void
Xtrace_message (const char *msgtext)
X{
X  fprintf(stderr, msgtext,
X      emethods->message_parm[0], emethods->message_parm[1],
X      emethods->message_parm[2], emethods->message_parm[3],
X      emethods->message_parm[4], emethods->message_parm[5],
X      emethods->message_parm[6], emethods->message_parm[7]);
X  fprintf(stderr, "\n");    /* there is no \n in the format string! */
X}
X
X/*
X * The error_exit() routine should not return to its caller.  The default
X * routine calls exit(), but here we assume that we want to return to
X * read_JPEG_data, which has set up a setjmp context for the purpose.
X * You should make sure that the free_all method is called, either within
X * error_exit or after the return to the outer-level routine.
X */
X
XMETHODDEF void
Xerror_exit (const char *msgtext)
X{
X  trace_message(msgtext);    /* report the error message */
X  (*emethods->free_all) ();    /* clean up memory allocation & temp files */
X  longjmp(setjmp_buffer, 1);    /* return control to outer routine */
X}
X
X
X
X/*
X * To accept the image data from decompression, you must define four routines
X * output_init, put_color_map, put_pixel_rows, and output_term.
X *
X * You must understand the distinction between full color output mode
X * (N independent color components) and colormapped output mode (a single
X * output component representing an index into a color map).  You should use
X * colormapped mode to write to a colormapped display screen or output file.
X * Colormapped mode is also useful for reducing grayscale output to a small
X * number of gray levels: when using the 1-pass quantizer on grayscale data,
X * the colormap entries will be evenly spaced from 0 to MAX_JSAMPLE, so you
X * can regard the indexes are directly representing gray levels at reduced
X * precision.  In any other case, you should not depend on the colormap
X * entries having any particular order.
X * To get colormapped output, set cinfo->quantize_colors to TRUE and set
X * cinfo->desired_number_of_colors to the maximum number of entries in the
X * colormap.  This can be done either in your main routine or in
X * d_ui_method_selection.  For grayscale quantization, also set
X * cinfo->two_pass_quantize to FALSE to ensure the 1-pass quantizer is used
X * (presently this is the default, but it may not be so in the future).
X *
X * The output file writing modules (jwrppm.c, jwrgif.c, jwrtarga.c, etc) may be
X * useful examples of what these routines should actually do, although each of
X * them is encrusted with a lot of specialized code for its own file format.
X */
X
X
XMETHODDEF void
Xoutput_init (decompress_info_ptr cinfo)
X/* This routine should do any setup required */
X{
X  /* This routine can initialize for output based on the data passed in cinfo.
X   * Useful fields include:
X   *    image_width, image_height    Pretty obvious, I hope.
X   *    data_precision            bits per pixel value; typically 8.
X   *    out_color_space            output colorspace previously requested
X   *    color_out_comps            number of color components in same
X   *    final_out_comps            number of components actually output
X   * final_out_comps is 1 if quantize_colors is true, else it is equal to
X   * color_out_comps.
X   *
X   * If you have requested color quantization, the colormap is NOT yet set.
X   * You may wish to defer output initialization until put_color_map is called.
X   */
X}
X
X
X/*
X * This routine is called if and only if you have set cinfo->quantize_colors
X * to TRUE.  It is given the selected colormap and can complete any required
X * initialization.  This call will occur after output_init and before any
X * calls to put_pixel_rows.  Note that the colormap pointer is also placed
X * in a cinfo field, whence it can be used by put_pixel_rows or output_term.
X * num_colors will be less than or equal to desired_number_of_colors.
X *
X * The colormap data is supplied as a 2-D array of JSAMPLEs, indexed as
X *        JSAMPLE colormap[component][indexvalue]
X * where component runs from 0 to cinfo->color_out_comps-1, and indexvalue
X * runs from 0 to num_colors-1.  Note that this is actually an array of
X * pointers to arrays rather than a true 2D array, since C does not support
X * variable-size multidimensional arrays.
X * JSAMPLE is typically typedef'd as "unsigned char".  If you want your code
X * to be as portable as the JPEG code proper, you should always access JSAMPLE
X * values with the GETJSAMPLE() macro, which will do the right thing if the
X * machine has only signed chars.
X */
X
XMETHODDEF void
Xput_color_map (decompress_info_ptr cinfo, int num_colors, JSAMPARRAY colormap)
X/* Write the color map */
X{
X  /* You need not provide this routine if you always set cinfo->quantize_colors
X   * FALSE; but a safer practice is to provide it and have it just print an
X   * error message, like this:
X   */
X  fprintf(stderr, "put_color_map called: there's a bug here somewhere!\n");
X}
X
X
X/*
X * This function is called repeatedly, with a few more rows of pixels supplied
X * on each call.  With the current JPEG code, some multiple of 8 rows will be
X * passed on each call except the last, but it is extremely bad form to depend
X * on this.  You CAN assume num_rows > 0.
X * The data is supplied in top-to-bottom row order (the standard order within
X * a JPEG file).  If you cannot readily use the data in that order, you'll
X * need an intermediate array to hold the image.  See jwrrle.c for an example
X * of outputting data in bottom-to-top order.
X *
X * The data is supplied as a 3-D array of JSAMPLEs, indexed as
X *        JSAMPLE pixel_data[component][row][column]
X * where component runs from 0 to cinfo->final_out_comps-1, row runs from 0 to
X * num_rows-1, and column runs from 0 to cinfo->image_width-1 (column 0 is
X * left edge of image).  Note that this is actually an array of pointers to
X * pointers to arrays rather than a true 3D array, since C does not support
X * variable-size multidimensional arrays.
X * JSAMPLE is typically typedef'd as "unsigned char".  If you want your code
X * to be as portable as the JPEG code proper, you should always access JSAMPLE
X * values with the GETJSAMPLE() macro, which will do the right thing if the
X * machine has only signed chars.
X *
X * If quantize_colors is true, then there is only one component, and its values
X * are indexes into the previously supplied colormap.  Otherwise the values
X * are actual data in your selected output colorspace.
X */
X
X
XMETHODDEF void
Xput_pixel_rows (decompress_info_ptr cinfo, int num_rows, JSAMPIMAGE pixel_data)
X/* Write some rows of output data */
X{
X  /* This example shows how you might write full-color RGB data (3 components)
X   * to an output file in which the data is stored 3 bytes per pixel.
X   */
X  register FILE * outfile = cinfo->output_file;
X  register JSAMPROW ptr0, ptr1, ptr2;
X  register long col;
X  register int row;
X
X  for (row = 0; row < num_rows; row++) {
X    ptr0 = pixel_data[0][row];
X    ptr1 = pixel_data[1][row];
X    ptr2 = pixel_data[2][row];
X    for (col = 0; col < cinfo->image_width; col++) {
X      putc(GETJSAMPLE(*ptr0), outfile);    /* red */
X      ptr0++;
X      putc(GETJSAMPLE(*ptr1), outfile);    /* green */
X      ptr1++;
X      putc(GETJSAMPLE(*ptr2), outfile);    /* blue */
X      ptr2++;
X    }
X  }
X}
X
X
XMETHODDEF void
Xoutput_term (decompress_info_ptr cinfo)
X/* Finish up at the end of the output */
X{
X  /* This termination routine may not need to do anything. */
X  /* Note that the JPEG code will only call it during successful exit; */
X  /* if you want it called during error exit, you gotta do that yourself. */
X}
X
X
X/*
X * That's it for the routines that deal with writing the output image.
X * Now we have overall control and parameter selection routines.
X */
X
X
X/*
X * This routine gets control after the JPEG file header has been read;
X * at this point the image size and colorspace are known.
X * The routine must determine what output routines are to be used, and make
X * any decompression parameter changes that are desirable.  For example,
X * if it is found that the JPEG file is grayscale, you might want to do
X * things differently than if it is color.  You can also delay setting
X * quantize_colors and associated options until this point.
X *
X * j_d_defaults initializes out_color_space to CS_RGB.  If you want grayscale
X * output you should set out_color_space to CS_GRAYSCALE.  Note that you can
X * force grayscale output from a color JPEG file (though not vice versa).
X */
X
XMETHODDEF void
Xd_ui_method_selection (decompress_info_ptr cinfo)
X{
X  /* if grayscale input, force grayscale output; */
X  /* else leave the output colorspace as set by main routine. */
X  if (cinfo->jpeg_color_space == CS_GRAYSCALE)
X    cinfo->out_color_space = CS_GRAYSCALE;
X
X  /* select output routines */
X  cinfo->methods->output_init = output_init;
X  cinfo->methods->put_color_map = put_color_map;
X  cinfo->methods->put_pixel_rows = put_pixel_rows;
X  cinfo->methods->output_term = output_term;
X}
X
X
X/*
X * OK, here is the main function that actually causes everything to happen.
X * We assume here that the JPEG filename is supplied by the caller of this
X * routine, and that all decompression parameters can be default values.
X * The routine returns 1 if successful, 0 if not.
X */
X
XGLOBAL int
Xread_JPEG_file (char * filename)
X{
X  /* These three structs contain JPEG parameters and working data.
X   * They must survive for the duration of parameter setup and one
X   * call to jpeg_decompress; typically, making them local data in the
X   * calling routine is the best strategy.
X   */
X  struct decompress_info_struct cinfo;
X  struct decompress_methods_struct dc_methods;
X  struct external_methods_struct e_methods;
X
X  /* Select the input and output files.
X   * In this example we want to open the input file before doing anything else,
X   * so that the setjmp() error recovery below can assume the file is open.
X   * Note that cinfo.output_file is only used if your output handling routines
X   * use it; otherwise, you can just make it NULL.
X   * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
X   * requires it in order to read binary files.
X   */
X
X  if ((cinfo.input_file = fopen(filename, "rb")) == NULL) {
X    fprintf(stderr, "can't open %s\n", filename);
X    return 0;
X  }
X
X  cinfo.output_file = NULL;    /* if no actual output file involved */
X
X  /* Initialize the system-dependent method pointers. */
X  cinfo.methods = &dc_methods;    /* links to method structs */
X  cinfo.emethods = &e_methods;
X  /* Here we supply our own error handler; compare to use of standard error
X   * handler in the previous write_JPEG_file example.
X   */
X  emethods = &e_methods;    /* save struct addr for possible access */
X  e_methods.error_exit = error_exit; /* supply error-exit routine */
X  e_methods.trace_message = trace_message; /* supply trace-message routine */
X
X  /* prepare setjmp context for possible exit from error_exit */
X  if (setjmp(setjmp_buffer)) {
X    /* If we get here, the JPEG code has signaled an error.
X     * Memory allocation has already been cleaned up (see free_all call in
X     * error_exit), but we need to close the input file before returning.
X     * You might also need to close an output file, etc.
X     */
X    fclose(cinfo.input_file);
X    return 0;
X  }
X
X  /* Here we use the standard memory manager provided with the JPEG code.
X   * In some cases you might want to replace the memory manager, or at
X   * least the system-dependent part of it, with your own code.
X   */
X  jselmemmgr(&e_methods);    /* select std memory allocation routines */
X  /* If the decompressor requires full-image buffers (for two-pass color
X   * quantization or a noninterleaved JPEG file), it will create temporary
X   * files for anything that doesn't fit within the maximum-memory setting.
X   * You can change the default maximum-memory setting by changing
X   * e_methods.max_memory_to_use after jselmemmgr returns.
X   * On some systems you may also need to set up a signal handler to
X   * ensure that temporary files are deleted if the program is interrupted.
X   * (This is most important if you are on MS-DOS and use the jmemdos.c
X   * memory manager back end; it will try to grab extended memory for
X   * temp files, and that space will NOT be freed automatically.)
X   * See jcmain.c or jdmain.c for an example signal handler.
X   */
X
X  /* Here, set up the pointer to your own routine for post-header-reading
X   * parameter selection.  You could also initialize the pointers to the
X   * output data handling routines here, if they are not dependent on the
X   * image type.
X   */
X  dc_methods.d_ui_method_selection = d_ui_method_selection;
X
X  /* Set up default decompression parameters. */
X  j_d_defaults(&cinfo, TRUE);
X  /* TRUE indicates that an input buffer should be allocated.
X   * In unusual cases you may want to allocate the input buffer yourself;
X   * see jddeflts.c for commentary.
X   */
X
X  /* At this point you can modify the default parameters set by j_d_defaults
X   * as needed; for example, you can request color quantization or force
X   * grayscale output.  See jdmain.c for examples of what you might change.
X   */
X
X  /* Set up to read a JFIF or baseline-JPEG file. */
X  /* This is the only JPEG file format currently supported. */
X  jselrjfif(&cinfo);
X
X  /* Here we go! */
X  jpeg_decompress(&cinfo);
X
X  /* That's it, son.  Nothin' else to do, except close files. */
X  /* Here we assume only the input file need be closed. */
X  fclose(cinfo.input_file);
X
X  return 1;            /* indicate success */
X
X  /* Note: if you want to decompress more than one image, we recommend you
X   * repeat this whole routine.  You MUST repeat the j_d_defaults()/alter
X   * parameters/jpeg_decompress() sequence, as some data structures allocated
X   * in j_d_defaults are freed upon exit from jpeg_decompress.
X   */
X}
END_OF_FILE
  if test 26472 -ne `wc -c <'example.c'`; then
    echo shar: \"'example.c'\" unpacked with wrong size!
  fi
  # end of 'example.c'
fi
if test -f 'jmemnobs.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'jmemnobs.c'\"
else
  echo shar: Extracting \"'jmemnobs.c'\" \(2263 characters\)
  sed "s/^X//" >'jmemnobs.c' <<'END_OF_FILE'
X/*
X * jmemnobs.c  (jmemsys.c)
X *
X * Copyright (C) 1992, Thomas G. Lane.
X * This file is part of the Independent JPEG Group's software.
X * For conditions of distribution and use, see the accompanying README file.
X *
X * This file provides a really simple implementation of the system-
X * dependent portion of the JPEG memory manager.  This implementation
X * assumes that no backing-store files are needed: all required space
X * can be obtained from malloc().
X * This is very portable in the sense that it'll compile on almost anything,
X * but you'd better have lots of main memory (or virtual memory) if you want
X * to process big images.
X * Note that the max_memory_to_use option is ignored by this implementation.
X */
X
X#include "jinclude.h"
X#include "jmemsys.h"
X
X#ifdef INCLUDES_ARE_ANSI
X#include <stdlib.h>        /* to declare malloc(), free() */
X#else
Xextern void * malloc PP((size_t size));
Xextern void free PP((void *ptr));
X#endif
X
X
Xstatic external_methods_ptr methods; /* saved for access to error_exit */
X
X
X/*
X * Memory allocation and freeing are controlled by the regular library
X * routines malloc() and free().
X */
X
XGLOBAL void *
Xjget_small (size_t sizeofobject)
X{
X  return (void *) malloc(sizeofobject);
X}
X
XGLOBAL void
Xjfree_small (void * object)
X{
X  free(object);
X}
X
X/*
X * We assume NEED_FAR_POINTERS is not defined and so the separate entry points
X * jget_large, jfree_large are not needed.
X */
X
X
X/*
X * This routine computes the total memory space available for allocation.
X * Here we always say, "we got all you want bud!"
X */
X
XGLOBAL long
Xjmem_available (long min_bytes_needed, long max_bytes_needed)
X{
X  return max_bytes_needed;
X}
X
X
X/*
X * Backing store (temporary file) management.
X * This should never be called and we just error out.
X */
X
XGLOBAL void
Xjopen_backing_store (backing_store_ptr info, long total_bytes_needed)
X{
X  ERREXIT(methods, "Backing store not supported");
X}
X
X
X/*
X * These routines take care of any system-dependent initialization and
X * cleanup required.  Keep in mind that jmem_term may be called more than
X * once.
X */
X
XGLOBAL void
Xjmem_init (external_methods_ptr emethods)
X{
X  methods = emethods;        /* save struct addr for error exit access */
X  emethods->max_memory_to_use = 0;
X}
X
XGLOBAL void
Xjmem_term (void)
X{
X  /* no work */
X}
END_OF_FILE
  if test 2263 -ne `wc -c <'jmemnobs.c'`; then
    echo shar: \"'jmemnobs.c'\" unpacked with wrong size!
  fi
  # end of 'jmemnobs.c'
fi
if test -f 'jquant1.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'jquant1.c'\"
else
  echo shar: Extracting \"'jquant1.c'\" \(21850 characters\)
  sed "s/^X//" >'jquant1.c' <<'END_OF_FILE'
X/*
X * jquant1.c
X *
X * Copyright (C) 1991, 1992, Thomas G. Lane.
X * This file is part of the Independent JPEG Group's software.
X * For conditions of distribution and use, see the accompanying README file.
X *
X * This file contains 1-pass color quantization (color mapping) routines.
X * These routines are invoked via the methods color_quantize
X * and color_quant_init/term.
X */
X
X#include "jinclude.h"
X
X#ifdef QUANT_1PASS_SUPPORTED
X
X
X/*
X * The main purpose of 1-pass quantization is to provide a fast, if not very
X * high quality, colormapped output capability.  A 2-pass quantizer usually
X * gives better visual quality; however, for quantized grayscale output this
X * quantizer is perfectly adequate.  Dithering is highly recommended with this
X * quantizer, though you can turn it off if you really want to.
X *
X * This implementation quantizes in the output colorspace.  This has a couple
X * of disadvantages: each pixel must be individually color-converted, and if
X * the color conversion includes gamma correction then quantization is done in
X * a nonlinear space, which is less desirable.  The major advantage is that
X * with the usual output color spaces (RGB, grayscale) an orthogonal grid of
X * representative colors can be used, thus permitting the very simple and fast
X * color lookup scheme used here.  The standard JPEG colorspace (YCbCr) cannot
X * be effectively handled this way, because only about a quarter of an
X * orthogonal grid would fall within the gamut of realizable colors.  Another
X * advantage is that when the user wants quantized grayscale output from a
X * color JPEG file, this quantizer can provide a high-quality result with no
X * special hacking.
X *
X * The gamma-correction problem could be eliminated by adjusting the grid
X * spacing to counteract the gamma correction applied by color_convert.
X * At this writing, gamma correction is not implemented by jdcolor, so
X * nothing is done here.
X *
X * In 1-pass quantization the colormap must be chosen in advance of seeing the
X * image.  We use a map consisting of all combinations of Ncolors[i] color
X * values for the i'th component.  The Ncolors[] values are chosen so that
X * their product, the total number of colors, is no more than that requested.
X * (In most cases, the product will be somewhat less.)
X *
X * Since the colormap is orthogonal, the representative value for each color
X * component can be determined without considering the other components;
X * then these indexes can be combined into a colormap index by a standard
X * N-dimensional-array-subscript calculation.  Most of the arithmetic involved
X * can be precalculated and stored in the lookup table colorindex[].
X * colorindex[i][j] maps pixel value j in component i to the nearest
X * representative value (grid plane) for that component; this index is
X * multiplied by the array stride for component i, so that the
X * index of the colormap entry closest to a given pixel value is just
X *    sum( colorindex[component-number][pixel-component-value] )
X * Aside from being fast, this scheme allows for variable spacing between
X * representative values with no additional lookup cost.
X */
X
X
X#define MAX_COMPONENTS 4    /* max components I can handle */
X
Xstatic JSAMPARRAY colormap;    /* The actual color map */
X/* colormap[i][j] = value of i'th color component for output pixel value j */
X
Xstatic JSAMPARRAY colorindex;    /* Precomputed mapping for speed */
X/* colorindex[i][j] = index of color closest to pixel value j in component i,
X * premultiplied as described above.  Since colormap indexes must fit into
X * JSAMPLEs, the entries of this array will too.
X */
X
Xstatic JSAMPARRAY input_buffer;    /* color conversion workspace */
X/* Since our input data is presented in the JPEG colorspace, we have to call
X * color_convert to get it into the output colorspace.  input_buffer is a
X * one-row-high workspace for the result of color_convert.
X */
X
X
X/* Declarations for Floyd-Steinberg dithering.
X *
X * Errors are accumulated into the arrays evenrowerrs[] and oddrowerrs[].
X * These have resolutions of 1/16th of a pixel count.  The error at a given
X * pixel is propagated to its unprocessed neighbors using the standard F-S
X * fractions,
X *        ...    (here)    7/16
X *        3/16    5/16    1/16
X * We work left-to-right on even rows, right-to-left on odd rows.
X *
X * In each of the xxxrowerrs[] arrays, indexing is [component#][position].
X * We provide (#columns + 2) entries per component; the extra entry at each
X * end saves us from special-casing the first and last pixels.
X * In evenrowerrs[], the entries for a component are stored left-to-right, but
X * in oddrowerrs[] they are stored right-to-left.  This means we always
X * process the current row's error entries in increasing order and the next
X * row's error entries in decreasing order, regardless of whether we are
X * working L-to-R or R-to-L in the pixel data!
X *
X * Note: on a wide image, we might not have enough room in a PC's near data
X * segment to hold the error arrays; so they are allocated with alloc_medium.
X */
X
X#ifdef EIGHT_BIT_SAMPLES
Xtypedef INT16 FSERROR;        /* 16 bits should be enough */
X#else
Xtypedef INT32 FSERROR;        /* may need more than 16 bits? */
X#endif
X
Xtypedef FSERROR FAR *FSERRPTR;    /* pointer to error array (in FAR storage!) */
X
Xstatic FSERRPTR evenrowerrs[MAX_COMPONENTS]; /* errors for even rows */
Xstatic FSERRPTR oddrowerrs[MAX_COMPONENTS];  /* errors for odd rows */
Xstatic boolean on_odd_row;    /* flag to remember which row we are on */
X
X
X/*
X * Policy-making subroutines for color_quant_init: these routines determine
X * the colormap to be used.  The rest of the module only assumes that the
X * colormap is orthogonal.
X *
X *  * select_ncolors decides how to divvy up the available colors
X *    among the components.
X *  * output_value defines the set of representative values for a component.
X *  * largest_input_value defines the mapping from input values to
X *    representative values for a component.
X * Note that the latter two routines may impose different policies for
X * different components, though this is not currently done.
X */
X
X
XLOCAL int
Xselect_ncolors (decompress_info_ptr cinfo, int Ncolors[])
X/* Determine allocation of desired colors to components, */
X/* and fill in Ncolors[] array to indicate choice. */
X/* Return value is total number of colors (product of Ncolors[] values). */
X{
X  int nc = cinfo->color_out_comps; /* number of color components */
X  int max_colors = cinfo->desired_number_of_colors;
X  int total_colors, iroot, i;
X  long temp;
X  boolean changed;
X
X  /* We can allocate at least the nc'th root of max_colors per component. */
X  /* Compute floor(nc'th root of max_colors). */
X  iroot = 1;
X  do {
X    iroot++;
X    temp = iroot;        /* set temp = iroot ** nc */
X    for (i = 1; i < nc; i++)
X      temp *= iroot;
X  } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */
X  iroot--;            /* now iroot = floor(root) */
X
X  /* Must have at least 2 color values per component */
X  if (iroot < 2)
X    ERREXIT1(cinfo->emethods, "Cannot quantize to fewer than %d colors",
X         (int) temp);
X
X  if (cinfo->out_color_space == CS_RGB && nc == 3) {
X    /* We provide a special policy for quantizing in RGB space.
X     * If 256 colors are requested, we allocate 8 red, 8 green, 4 blue levels;
X     * this corresponds to the common 3/3/2-bit scheme.  For other totals,
X     * the counts are set so that the number of colors allocated to each
X     * component are roughly in the proportion R 3, G 4, B 2.
X     * For low color counts, it's easier to hardwire the optimal choices
X     * than try to tweak the algorithm to generate them.
X     */
X    if (max_colors == 256) {
X      Ncolors[0] = 8;  Ncolors[1] = 8;  Ncolors[2] = 4;
X      return 256;
X    }
X    if (max_colors < 12) {
X      /* Fixed mapping for 8 colors */
X      Ncolors[0] = Ncolors[1] = Ncolors[2] = 2;
X    } else if (max_colors < 18) {
X      /* Fixed mapping for 12 colors */
X      Ncolors[0] = 2;  Ncolors[1] = 3;  Ncolors[2] = 2;
X    } else if (max_colors < 24) {
X      /* Fixed mapping for 18 colors */
X      Ncolors[0] = 3;  Ncolors[1] = 3;  Ncolors[2] = 2;
X    } else if (max_colors < 27) {
X      /* Fixed mapping for 24 colors */
X      Ncolors[0] = 3;  Ncolors[1] = 4;  Ncolors[2] = 2;
X    } else if (max_colors < 36) {
X      /* Fixed mapping for 27 colors */
X      Ncolors[0] = 3;  Ncolors[1] = 3;  Ncolors[2] = 3;
X    } else {
X      /* these weights are readily derived with a little algebra */
X      Ncolors[0] = (iroot * 266) >> 8; /* R weight is 1.0400 */
X      Ncolors[1] = (iroot * 355) >> 8; /* G weight is 1.3867 */
X      Ncolors[2] = (iroot * 177) >> 8; /* B weight is 0.6934 */
X    }
X    total_colors = Ncolors[0] * Ncolors[1] * Ncolors[2];
X    /* The above computation produces "floor" values, so we may be able to
X     * increment the count for one or more components without exceeding
X     * max_colors.  We try in the order B, G, R.
X     */
X    do {
X      changed = FALSE;
X      for (i = 2; i >= 0; i--) {
X    /* calculate new total_colors if Ncolors[i] is incremented */
X    temp = total_colors / Ncolors[i];
X    temp *= Ncolors[i]+1;    /* done in long arith to avoid oflo */
X    if (temp <= (long) max_colors) {
X      Ncolors[i]++;        /* OK, apply the increment */
X      total_colors = (int) temp;
X      changed = TRUE;
X    }
X      }
X    } while (changed);        /* loop until no increment is possible */
X  } else {
X    /* For any colorspace besides RGB, treat all the components equally. */
X
X    /* Initialize to iroot color values for each component */
X    total_colors = 1;
X    for (i = 0; i < nc; i++) {
X      Ncolors[i] = iroot;
X      total_colors *= iroot;
X    }
X    /* We may be able to increment the count for one or more components without
X     * exceeding max_colors, though we know not all can be incremented.
X     */
X    for (i = 0; i < nc; i++) {
X      /* calculate new total_colors if Ncolors[i] is incremented */
X      temp = total_colors / Ncolors[i];
X      temp *= Ncolors[i]+1;    /* done in long arith to avoid oflo */
X      if (temp > (long) max_colors)
X    break;            /* won't fit, done */
X      Ncolors[i]++;        /* OK, apply the increment */
X      total_colors = (int) temp;
X    }
X  }
X
X  return total_colors;
X}
X
X
XLOCAL int
Xoutput_value (decompress_info_ptr cinfo, int ci, int j, int maxj)
X/* Return j'th output value, where j will range from 0 to maxj */
X/* The output values must fall in 0..MAXJSAMPLE in increasing order */
X{
X  /* We always provide values 0 and MAXJSAMPLE for each component;
X   * any additional values are equally spaced between these limits.
X   * (Forcing the upper and lower values to the limits ensures that
X   * dithering can't produce a color outside the selected gamut.)
X   */
X  return (j * MAXJSAMPLE + maxj/2) / maxj;
X}
X
X
XLOCAL int
Xlargest_input_value (decompress_info_ptr cinfo, int ci, int j, int maxj)
X/* Return largest input value that should map to j'th output value */
X/* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */
X{
X  /* Breakpoints are halfway between values returned by output_value */
X  return ((2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj);
X}
X
X
X/*
X * Initialize for one-pass color quantization.
X */
X
XMETHODDEF void
Xcolor_quant_init (decompress_info_ptr cinfo)
X{
X  int total_colors;        /* Number of distinct output colors */
X  int Ncolors[MAX_COMPONENTS];    /* # of values alloced to each component */
X  int i,j,k, nci, blksize, blkdist, ptr, val;
X
X  /* Make sure my internal arrays won't overflow */
X  if (cinfo->num_components > MAX_COMPONENTS ||
X      cinfo->color_out_comps > MAX_COMPONENTS)
X    ERREXIT1(cinfo->emethods, "Cannot quantize more than %d color components",
X         MAX_COMPONENTS);
X  /* Make sure colormap indexes can be represented by JSAMPLEs */
X  if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1))
X    ERREXIT1(cinfo->emethods, "Cannot request more than %d quantized colors",
X         MAXJSAMPLE+1);
X
X  /* Select number of colors for each component */
X  total_colors = select_ncolors(cinfo, Ncolors);
X
X  /* Report selected color counts */
X  if (cinfo->color_out_comps == 3)
X    TRACEMS4(cinfo->emethods, 1, "Quantizing to %d = %d*%d*%d colors",
X         total_colors, Ncolors[0], Ncolors[1], Ncolors[2]);
X  else
X    TRACEMS1(cinfo->emethods, 1, "Quantizing to %d colors", total_colors);
X
X  /* Allocate and fill in the colormap and color index. */
X  /* The colors are ordered in the map in standard row-major order, */
X  /* i.e. rightmost (highest-indexed) color changes most rapidly. */
X
X  colormap = (*cinfo->emethods->alloc_small_sarray)
X        ((long) total_colors, (long) cinfo->color_out_comps);
X  colorindex = (*cinfo->emethods->alloc_small_sarray)
X        ((long) (MAXJSAMPLE+1), (long) cinfo->color_out_comps);
X
X  /* blksize is number of adjacent repeated entries for a component */
X  /* blkdist is distance between groups of identical entries for a component */
X  blkdist = total_colors;
X
X  for (i = 0; i < cinfo->color_out_comps; i++) {
X    /* fill in colormap entries for i'th color component */
X    nci = Ncolors[i];        /* # of distinct values for this color */
X    blksize = blkdist / nci;
X    for (j = 0; j < nci; j++) {
X      /* Compute j'th output value (out of nci) for component */
X      val = output_value(cinfo, i, j, nci-1);
X      /* Fill in all colormap entries that have this value of this component */
X      for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) {
X    /* fill in blksize entries beginning at ptr */
X    for (k = 0; k < blksize; k++)
X      colormap[i][ptr+k] = (JSAMPLE) val;
X      }
X    }
X    blkdist = blksize;        /* blksize of this color is blkdist of next */
X
X    /* fill in colorindex entries for i'th color component */
X    /* in loop, val = index of current output value, */
X    /* and k = largest j that maps to current val */
X    val = 0;
X    k = largest_input_value(cinfo, i, 0, nci-1);
X    for (j = 0; j <= MAXJSAMPLE; j++) {
X      while (j > k)        /* advance val if past boundary */
X    k = largest_input_value(cinfo, i, ++val, nci-1);
X      /* premultiply so that no multiplication needed in main processing */
X      colorindex[i][j] = (JSAMPLE) (val * blksize);
X    }
X  }
X
X  /* Pass the colormap to the output module. */
X  /* NB: the output module may continue to use the colormap until shutdown. */
X  cinfo->colormap = colormap;
X  cinfo->actual_number_of_colors = total_colors;
X  (*cinfo->methods->put_color_map) (cinfo, total_colors, colormap);
X
X  /* Allocate workspace to hold one row of color-converted data */
X  input_buffer = (*cinfo->emethods->alloc_small_sarray)
X            (cinfo->image_width, (long) cinfo->color_out_comps);
X
X  /* Allocate Floyd-Steinberg workspace if necessary */
X  if (cinfo->use_dithering) {
X    size_t arraysize = (size_t) ((cinfo->image_width + 2L) * SIZEOF(FSERROR));
X
X    for (i = 0; i < cinfo->color_out_comps; i++) {
X      evenrowerrs[i] = (FSERRPTR) (*cinfo->emethods->alloc_medium) (arraysize);
X      oddrowerrs[i]  = (FSERRPTR) (*cinfo->emethods->alloc_medium) (arraysize);
X      /* we only need to zero the forward contribution for current row. */
X      jzero_far((void FAR *) evenrowerrs[i], arraysize);
X    }
X    on_odd_row = FALSE;
X  }
X}
X
X
X/*
X * Subroutines for color conversion methods.
X */
X
XLOCAL void
Xdo_color_conversion (decompress_info_ptr cinfo, JSAMPIMAGE input_data, int row)
X/* Convert the indicated row of the input data into output colorspace */
X/* in input_buffer.  This requires a little trickery since color_convert */
X/* expects to deal with 3-D arrays; fortunately we can fake it out */
X/* at fairly low cost. */
X{
X  short ci;
X  JSAMPARRAY input_hack[MAX_COMPONENTS];
X  JSAMPARRAY output_hack[MAX_COMPONENTS];
X
X  /* create JSAMPIMAGE pointing at specified row of input_data */
X  for (ci = 0; ci < cinfo->num_components; ci++)
X    input_hack[ci] = input_data[ci] + row;
X  /* Create JSAMPIMAGE pointing at input_buffer */
X  for (ci = 0; ci < cinfo->color_out_comps; ci++)
X    output_hack[ci] = &(input_buffer[ci]);
X
X  (*cinfo->methods->color_convert) (cinfo, 1, cinfo->image_width,
X                    input_hack, output_hack);
X}
X
X
X/*
X * Map some rows of pixels to the output colormapped representation.
X */
X
XMETHODDEF void
Xcolor_quantize (decompress_info_ptr cinfo, int num_rows,
X        JSAMPIMAGE input_data, JSAMPARRAY output_data)
X/* General case, no dithering */
X{
X  register int pixcode, ci;
X  register JSAMPROW ptrout;
X  register long col;
X  int row;
X  long width = cinfo->image_width;
X  register int nc = cinfo->color_out_comps;
X
X  for (row = 0; row < num_rows; row++) {
X    do_color_conversion(cinfo, input_data, row);
X    ptrout = output_data[row];
X    for (col = 0; col < width; col++) {
X      pixcode = 0;
X      for (ci = 0; ci < nc; ci++) {
X    pixcode += GETJSAMPLE(colorindex[ci]
X                  [GETJSAMPLE(input_buffer[ci][col])]);
X      }
X      *ptrout++ = (JSAMPLE) pixcode;
X    }
X  }
X}
X
X
XMETHODDEF void
Xcolor_quantize3 (decompress_info_ptr cinfo, int num_rows,
X         JSAMPIMAGE input_data, JSAMPARRAY output_data)
X/* Fast path for color_out_comps==3, no dithering */
X{
X  register int pixcode;
X  register JSAMPROW ptr0, ptr1, ptr2, ptrout;
X  register long col;
X  int row;
X  long width = cinfo->image_width;
X
X  for (row = 0; row < num_rows; row++) {
X    do_color_conversion(cinfo, input_data, row);
X    ptr0 = input_buffer[0];
X    ptr1 = input_buffer[1];
X    ptr2 = input_buffer[2];
X    ptrout = output_data[row];
X    for (col = width; col > 0; col--) {
X      pixcode  = GETJSAMPLE(colorindex[0][GETJSAMPLE(*ptr0++)]);
X      pixcode += GETJSAMPLE(colorindex[1][GETJSAMPLE(*ptr1++)]);
X      pixcode += GETJSAMPLE(colorindex[2][GETJSAMPLE(*ptr2++)]);
X      *ptrout++ = (JSAMPLE) pixcode;
X    }
X  }
X}
X
X
XMETHODDEF void
Xcolor_quantize_dither (decompress_info_ptr cinfo, int num_rows,
X               JSAMPIMAGE input_data, JSAMPARRAY output_data)
X/* General case, with Floyd-Steinberg dithering */
X{
X  register FSERROR val;
X  FSERROR two_val;
X  register FSERRPTR thisrowerr, nextrowerr;
X  register JSAMPROW input_ptr;
X  register JSAMPROW output_ptr;
X  JSAMPROW colorindex_ci;
X  JSAMPROW colormap_ci;
X  register int pixcode;
X  int dir;            /* 1 for left-to-right, -1 for right-to-left */
X  int ci;
X  int nc = cinfo->color_out_comps;
X  int row;
X  long col_counter;
X  long width = cinfo->image_width;
X
X  for (row = 0; row < num_rows; row++) {
X    do_color_conversion(cinfo, input_data, row);
X    /* Initialize output values to 0 so can process components separately */
X    jzero_far((void FAR *) output_data[row],
X          (size_t) (width * SIZEOF(JSAMPLE)));
X    for (ci = 0; ci < nc; ci++) {
X      if (on_odd_row) {
X    /* work right to left in this row */
X    dir = -1;
X    input_ptr = input_buffer[ci] + (width-1);
X    output_ptr = output_data[row] + (width-1);
X    thisrowerr = oddrowerrs[ci] + 1;
X    nextrowerr = evenrowerrs[ci] + width;
X      } else {
X    /* work left to right in this row */
X    dir = 1;
X    input_ptr = input_buffer[ci];
X    output_ptr = output_data[row];
X    thisrowerr = evenrowerrs[ci] + 1;
X    nextrowerr = oddrowerrs[ci] + width;
X      }
X      colorindex_ci = colorindex[ci];
X      colormap_ci = colormap[ci];
X      *nextrowerr = 0;        /* need only initialize this one entry */
X      for (col_counter = width; col_counter > 0; col_counter--) {
X    /* Compute pixel value + accumulated error for this component */
X    val = (((FSERROR) GETJSAMPLE(*input_ptr)) << 4) + *thisrowerr;
X    if (val < 0) val = 0;    /* must watch for range overflow! */
X    else {
X      val += 8;        /* divide by 16 with proper rounding */
X      val >>= 4;
X      if (val > MAXJSAMPLE) val = MAXJSAMPLE;
X    }
X    /* Select output value, accumulate into output code for this pixel */
X    pixcode = GETJSAMPLE(*output_ptr);
X    pixcode += GETJSAMPLE(colorindex_ci[val]);
X    *output_ptr = (JSAMPLE) pixcode;
X    /* Compute actual representation error at this pixel */
X    /* Note: we can do this even though we don't yet have the final */
X    /* value of pixcode, because the colormap is orthogonal. */
X    val -= (FSERROR) GETJSAMPLE(colormap_ci[pixcode]);
X    /* Propagate error to (same component of) adjacent pixels */
X    /* Remember that nextrowerr entries are in reverse order! */
X    two_val = val * 2;
X    nextrowerr[-1]  = val; /* not +=, since not initialized yet */
X    val += two_val;        /* form error * 3 */
X    nextrowerr[ 1] += val;
X    val += two_val;        /* form error * 5 */
X    nextrowerr[ 0] += val;
X    val += two_val;        /* form error * 7 */
X    thisrowerr[ 1] += val;
X    input_ptr += dir;    /* advance input ptr to next column */
X    output_ptr += dir;    /* advance output ptr to next column */
X    thisrowerr++;        /* cur-row error ptr advances to right */
X    nextrowerr--;        /* next-row error ptr advances to left */
X      }
X    }
X    on_odd_row = (on_odd_row ? FALSE : TRUE);
X  }
X}
X
X
X/*
X * Finish up at the end of the file.
X */
X
XMETHODDEF void
Xcolor_quant_term (decompress_info_ptr cinfo)
X{
X  /* no work (we let free_all release the workspace) */
X  /* Note that we *mustn't* free the colormap before free_all, */
X  /* since output module may use it! */
X}
X
X
X/*
X * Prescan some rows of pixels.
X * Not used in one-pass case.
X */
X
XMETHODDEF void
Xcolor_quant_prescan (decompress_info_ptr cinfo, int num_rows,
X             JSAMPIMAGE image_data, JSAMPARRAY workspace)
X{
X  ERREXIT(cinfo->emethods, "Should not get here!");
X}
X
X
X/*
X * Do two-pass quantization.
X * Not used in one-pass case.
X */
X
XMETHODDEF void
Xcolor_quant_doit (decompress_info_ptr cinfo, quantize_caller_ptr source_method)
X{
X  ERREXIT(cinfo->emethods, "Should not get here!");
X}
X
X
X/*
X * The method selection routine for 1-pass color quantization.
X */
X
XGLOBAL void
Xjsel1quantize (decompress_info_ptr cinfo)
X{
X  if (! cinfo->two_pass_quantize) {
X    cinfo->methods->color_quant_init = color_quant_init;
X    if (cinfo->use_dithering) {
X      cinfo->methods->color_quantize = color_quantize_dither;
X    } else {
X      if (cinfo->color_out_comps == 3)
X    cinfo->methods->color_quantize = color_quantize3;
X      else
X    cinfo->methods->color_quantize = color_quantize;
X    }
X    cinfo->methods->color_quant_prescan = color_quant_prescan;
X    cinfo->methods->color_quant_doit = color_quant_doit;
X    cinfo->methods->color_quant_term = color_quant_term;
X  }
X}
X
X#endif /* QUANT_1PASS_SUPPORTED */
END_OF_FILE
  if test 21850 -ne `wc -c <'jquant1.c'`; then
    echo shar: \"'jquant1.c'\" unpacked with wrong size!
  fi
  # end of 'jquant1.c'
fi
echo shar: End of archive 9 \(of 18\).
cp /dev/null ark9isdone
MISSING=""
for I in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ; do
    if test ! -f ark${I}isdone ; then
    MISSING="${MISSING} ${I}"
    fi
done
if test "${MISSING}" = "" ; then
    echo You have unpacked all 18 archives.
    rm -f ark[1-9]isdone ark[1-9][0-9]isdone
else
    echo You still must unpack the following archives:
    echo "        " ${MISSING}
fi
exit 0
exit 0 # Just in case...