# dlib C++ Library - wrrle.c

    /*
     * wrrle.c
     *
     * Copyright (C) 1991-1996, 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 routines to write output images in RLE format.
     * The Utah Raster Toolkit library is required (version 3.1 or later).
     *
     * These routines may need modification for non-Unix environments or
     * specialized applications.  As they stand, they assume output to
     * an ordinary stdio stream.
     *
     * Based on code contributed by Mike Lijewski,
     * with updates from Robert Hutchinson.
     */

    #include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */

    #ifdef RLE_SUPPORTED

    /* rle.h is provided by the Utah Raster Toolkit. */

    #include <rle.h>

    /*
     * We assume that JSAMPLE has the same representation as rle_pixel,
     * to wit, "unsigned char".  Hence we can't cope with 12- or 16-bit samples.
     */

    #if BITS_IN_JSAMPLE != 8
      Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
    #endif

    /*
     * Since RLE stores scanlines bottom-to-top, we have to invert the image
     * from JPEG's top-to-bottom order.  To do this, we save the outgoing data
     * in a virtual array during put_pixel_row calls, then actually emit the
     * RLE file during finish_output.
     */

    /*
     * For now, if we emit an RLE color map then it is always 256 entries long,
     * though not all of the entries need be used.
     */

    #define CMAPBITS	8
    #define CMAPLENGTH	(1<<(CMAPBITS))

    typedef struct {
      struct djpeg_dest_struct pub; /* public fields */

      jvirt_sarray_ptr image;	/* virtual array to store the output image */
      rle_map *colormap;	 	/* RLE-style color map, or NULL if none */
      rle_pixel **rle_row;		/* To pass rows to rle_putrow() */

    } rle_dest_struct;

    typedef rle_dest_struct * rle_dest_ptr;

    /* Forward declarations */
    METHODDEF(void) rle_put_pixel_rows
        JPP((j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
    	 JDIMENSION rows_supplied));

    /*
     * Write the file header.
     *
     * In this module it's easier to wait till finish_output to write anything.
     */

    METHODDEF(void)
    start_output_rle (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
    {
      rle_dest_ptr dest = (rle_dest_ptr) dinfo;
      size_t cmapsize;
      int i, ci;
    #ifdef PROGRESS_REPORT
      cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
    #endif

      /*
       * Make sure the image can be stored in RLE format.
       *
       * - RLE stores image dimensions as *signed* 16 bit integers.  JPEG
       *   uses unsigned, so we have to check the width.
       *
       * - Colorspace is expected to be grayscale or RGB.
       *
       * - The number of channels (components) is expected to be 1 (grayscale/
       *   pseudocolor) or 3 (truecolor/directcolor).
       *   (could be 2 or 4 if using an alpha channel, but we aren't)
       */

      if (cinfo->output_width > 32767 || cinfo->output_height > 32767)
        ERREXIT2(cinfo, JERR_RLE_DIMENSIONS, cinfo->output_width,
    	     cinfo->output_height);

      if (cinfo->out_color_space != JCS_GRAYSCALE &&
          cinfo->out_color_space != JCS_RGB)
        ERREXIT(cinfo, JERR_RLE_COLORSPACE);

      if (cinfo->output_components != 1 && cinfo->output_components != 3)
        ERREXIT1(cinfo, JERR_RLE_TOOMANYCHANNELS, cinfo->num_components);

      /* Convert colormap, if any, to RLE format. */

      dest->colormap = NULL;

      if (cinfo->quantize_colors) {
        /* Allocate storage for RLE-style cmap, zero any extra entries */
        cmapsize = cinfo->out_color_components * CMAPLENGTH * SIZEOF(rle_map);
        dest->colormap = (rle_map *) (*cinfo->mem->alloc_small)
          ((j_common_ptr) cinfo, JPOOL_IMAGE, cmapsize);
        MEMZERO(dest->colormap, cmapsize);

        /* Save away data in RLE format --- note 8-bit left shift! */
        /* Shifting would need adjustment for JSAMPLEs wider than 8 bits. */
        for (ci = 0; ci < cinfo->out_color_components; ci++) {
          for (i = 0; i < cinfo->actual_number_of_colors; i++) {
            dest->colormap[ci * CMAPLENGTH + i] =
              GETJSAMPLE(cinfo->colormap[ci][i]) << 8;
          }
        }
      }

      /* Set the output buffer to the first row */
      dest->pub.buffer = (*cinfo->mem->access_virt_sarray)
        ((j_common_ptr) cinfo, dest->image, (JDIMENSION) 0, (JDIMENSION) 1, TRUE);
      dest->pub.buffer_height = 1;

      dest->pub.put_pixel_rows = rle_put_pixel_rows;

    #ifdef PROGRESS_REPORT
      if (progress != NULL) {
        progress->total_extra_passes++;  /* count file writing as separate pass */
      }
    #endif
    }

    /*
     * Write some pixel data.
     *
     * This routine just saves the data away in a virtual array.
     */

    METHODDEF(void)
    rle_put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
    		    JDIMENSION rows_supplied)
    {
      rle_dest_ptr dest = (rle_dest_ptr) dinfo;

      if (cinfo->output_scanline < cinfo->output_height) {
        dest->pub.buffer = (*cinfo->mem->access_virt_sarray)
          ((j_common_ptr) cinfo, dest->image,
           cinfo->output_scanline, (JDIMENSION) 1, TRUE);
      }
    }

    /*
     * Finish up at the end of the file.
     *
     * Here is where we really output the RLE file.
     */

    METHODDEF(void)
    finish_output_rle (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
    {
      rle_dest_ptr dest = (rle_dest_ptr) dinfo;
      rle_hdr header;		/* Output file information */
      rle_pixel **rle_row, *red, *green, *blue;
      JSAMPROW output_row;
      char cmapcomment[80];
      int row, col;
      int ci;
    #ifdef PROGRESS_REPORT
      cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
    #endif

      /* Initialize the header info */
      header = *rle_hdr_init(NULL);
      header.rle_file = dest->pub.output_file;
      header.xmin     = 0;
      header.xmax     = cinfo->output_width  - 1;
      header.ymin     = 0;
      header.ymax     = cinfo->output_height - 1;
      header.alpha    = 0;
      header.ncolors  = cinfo->output_components;
      for (ci = 0; ci < cinfo->output_components; ci++) {
        RLE_SET_BIT(header, ci);
      }
      if (cinfo->quantize_colors) {
        header.ncmap   = cinfo->out_color_components;
        header.cmaplen = CMAPBITS;
        header.cmap    = dest->colormap;
        /* Add a comment to the output image with the true colormap length. */
        sprintf(cmapcomment, "color_map_length=%d", cinfo->actual_number_of_colors);
        rle_putcom(cmapcomment, &header);
      }

      /* Emit the RLE header and color map (if any) */
      rle_put_setup(&header);

      /* Now output the RLE data from our virtual array.
       * We assume here that (a) rle_pixel is represented the same as JSAMPLE,
       * and (b) we are not on a machine where FAR pointers differ from regular.
       */

    #ifdef PROGRESS_REPORT
      if (progress != NULL) {
        progress->pub.pass_limit = cinfo->output_height;
        progress->pub.pass_counter = 0;
        (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
      }
    #endif

      if (cinfo->output_components == 1) {
        for (row = cinfo->output_height-1; row >= 0; row--) {
          rle_row = (rle_pixel **) (*cinfo->mem->access_virt_sarray)
            ((j_common_ptr) cinfo, dest->image,
    	 (JDIMENSION) row, (JDIMENSION) 1, FALSE);
          rle_putrow(rle_row, (int) cinfo->output_width, &header);
    #ifdef PROGRESS_REPORT
          if (progress != NULL) {
            progress->pub.pass_counter++;
            (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
          }
    #endif
        }
      } else {
        for (row = cinfo->output_height-1; row >= 0; row--) {
          rle_row = (rle_pixel **) dest->rle_row;
          output_row = * (*cinfo->mem->access_virt_sarray)
            ((j_common_ptr) cinfo, dest->image,
    	 (JDIMENSION) row, (JDIMENSION) 1, FALSE);
          red = rle_row[0];
          green = rle_row[1];
          blue = rle_row[2];
          for (col = cinfo->output_width; col > 0; col--) {
            *red++ = GETJSAMPLE(*output_row++);
            *green++ = GETJSAMPLE(*output_row++);
            *blue++ = GETJSAMPLE(*output_row++);
          }
          rle_putrow(rle_row, (int) cinfo->output_width, &header);
    #ifdef PROGRESS_REPORT
          if (progress != NULL) {
            progress->pub.pass_counter++;
            (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
          }
    #endif
        }
      }

    #ifdef PROGRESS_REPORT
      if (progress != NULL)
        progress->completed_extra_passes++;
    #endif

      /* Emit file trailer */
      rle_puteof(&header);
      fflush(dest->pub.output_file);
      if (ferror(dest->pub.output_file))
        ERREXIT(cinfo, JERR_FILE_WRITE);
    }

    /*
     * The module selection routine for RLE format output.
     */

    GLOBAL(djpeg_dest_ptr)
    jinit_write_rle (j_decompress_ptr cinfo)
    {
      rle_dest_ptr dest;

      /* Create module interface object, fill in method pointers */
      dest = (rle_dest_ptr)
          (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                                      SIZEOF(rle_dest_struct));
      dest->pub.start_output = start_output_rle;
      dest->pub.finish_output = finish_output_rle;

      /* Calculate output image dimensions so we can allocate space */
      jpeg_calc_output_dimensions(cinfo);

      /* Allocate a work array for output to the RLE library. */
      dest->rle_row = (*cinfo->mem->alloc_sarray)
        ((j_common_ptr) cinfo, JPOOL_IMAGE,
         cinfo->output_width, (JDIMENSION) cinfo->output_components);

      /* Allocate a virtual array to hold the image. */
      dest->image = (*cinfo->mem->request_virt_sarray)
        ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
         (JDIMENSION) (cinfo->output_width * cinfo->output_components),
         cinfo->output_height, (JDIMENSION) 1);

      return (djpeg_dest_ptr) dest;
    }

    #endif /* RLE_SUPPORTED */