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plt-scheme  4.2.1
rdrle.c
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00001 /*
00002  * rdrle.c
00003  *
00004  * Copyright (C) 1991-1996, Thomas G. Lane.
00005  * This file is part of the Independent JPEG Group's software.
00006  * For conditions of distribution and use, see the accompanying README file.
00007  *
00008  * This file contains routines to read input images in Utah RLE format.
00009  * The Utah Raster Toolkit library is required (version 3.1 or later).
00010  *
00011  * These routines may need modification for non-Unix environments or
00012  * specialized applications.  As they stand, they assume input from
00013  * an ordinary stdio stream.  They further assume that reading begins
00014  * at the start of the file; start_input may need work if the
00015  * user interface has already read some data (e.g., to determine that
00016  * the file is indeed RLE format).
00017  *
00018  * Based on code contributed by Mike Lijewski,
00019  * with updates from Robert Hutchinson.
00020  */
00021 
00022 #include "cdjpeg.h"         /* Common decls for cjpeg/djpeg applications */
00023 
00024 #ifdef RLE_SUPPORTED
00025 
00026 /* rle.h is provided by the Utah Raster Toolkit. */
00027 
00028 #include <rle.h>
00029 
00030 /*
00031  * We assume that JSAMPLE has the same representation as rle_pixel,
00032  * to wit, "unsigned char".  Hence we can't cope with 12- or 16-bit samples.
00033  */
00034 
00035 #if BITS_IN_JSAMPLE != 8
00036   Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
00037 #endif
00038 
00039 /*
00040  * We support the following types of RLE files:
00041  *   
00042  *   GRAYSCALE   - 8 bits, no colormap
00043  *   MAPPEDGRAY  - 8 bits, 1 channel colomap
00044  *   PSEUDOCOLOR - 8 bits, 3 channel colormap
00045  *   TRUECOLOR   - 24 bits, 3 channel colormap
00046  *   DIRECTCOLOR - 24 bits, no colormap
00047  *
00048  * For now, we ignore any alpha channel in the image.
00049  */
00050 
00051 typedef enum
00052   { GRAYSCALE, MAPPEDGRAY, PSEUDOCOLOR, TRUECOLOR, DIRECTCOLOR } rle_kind;
00053 
00054 
00055 /*
00056  * Since RLE stores scanlines bottom-to-top, we have to invert the image
00057  * to conform to JPEG's top-to-bottom order.  To do this, we read the
00058  * incoming image into a virtual array on the first get_pixel_rows call,
00059  * then fetch the required row from the virtual array on subsequent calls.
00060  */
00061 
00062 typedef struct _rle_source_struct * rle_source_ptr;
00063 
00064 typedef struct _rle_source_struct {
00065   struct cjpeg_source_struct pub; /* public fields */
00066 
00067   rle_kind visual;              /* actual type of input file */
00068   jvirt_sarray_ptr image;       /* virtual array to hold the image */
00069   JDIMENSION row;           /* current row # in the virtual array */
00070   rle_hdr header;               /* Input file information */
00071   rle_pixel** rle_row;          /* holds a row returned by rle_getrow() */
00072 
00073 } rle_source_struct;
00074 
00075 
00076 /*
00077  * Read the file header; return image size and component count.
00078  */
00079 
00080 METHODDEF(void)
00081 start_input_rle (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00082 {
00083   rle_source_ptr source = (rle_source_ptr) sinfo;
00084   JDIMENSION width, height;
00085 #ifdef PROGRESS_REPORT
00086   cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
00087 #endif
00088 
00089   /* Use RLE library routine to get the header info */
00090   source->header = *rle_hdr_init(NULL);
00091   source->header.rle_file = source->pub.input_file;
00092   switch (rle_get_setup(&(source->header))) {
00093   case RLE_SUCCESS:
00094     /* A-OK */
00095     break;
00096   case RLE_NOT_RLE:
00097     ERREXIT(cinfo, JERR_RLE_NOT);
00098     break;
00099   case RLE_NO_SPACE:
00100     ERREXIT(cinfo, JERR_RLE_MEM);
00101     break;
00102   case RLE_EMPTY:
00103     ERREXIT(cinfo, JERR_RLE_EMPTY);
00104     break;
00105   case RLE_EOF:
00106     ERREXIT(cinfo, JERR_RLE_EOF);
00107     break;
00108   default:
00109     ERREXIT(cinfo, JERR_RLE_BADERROR);
00110     break;
00111   }
00112 
00113   /* Figure out what we have, set private vars and return values accordingly */
00114   
00115   width  = source->header.xmax - source->header.xmin + 1;
00116   height = source->header.ymax - source->header.ymin + 1;
00117   source->header.xmin = 0;         /* realign horizontally */
00118   source->header.xmax = width-1;
00119 
00120   cinfo->image_width      = width;
00121   cinfo->image_height     = height;
00122   cinfo->data_precision   = 8;  /* we can only handle 8 bit data */
00123 
00124   if (source->header.ncolors == 1 && source->header.ncmap == 0) {
00125     source->visual     = GRAYSCALE;
00126     TRACEMS2(cinfo, 1, JTRC_RLE_GRAY, width, height);
00127   } else if (source->header.ncolors == 1 && source->header.ncmap == 1) {
00128     source->visual     = MAPPEDGRAY;
00129     TRACEMS3(cinfo, 1, JTRC_RLE_MAPGRAY, width, height,
00130              1 << source->header.cmaplen);
00131   } else if (source->header.ncolors == 1 && source->header.ncmap == 3) {
00132     source->visual     = PSEUDOCOLOR;
00133     TRACEMS3(cinfo, 1, JTRC_RLE_MAPPED, width, height,
00134             1 << source->header.cmaplen);
00135   } else if (source->header.ncolors == 3 && source->header.ncmap == 3) {
00136     source->visual     = TRUECOLOR;
00137     TRACEMS3(cinfo, 1, JTRC_RLE_FULLMAP, width, height,
00138             1 << source->header.cmaplen);
00139   } else if (source->header.ncolors == 3 && source->header.ncmap == 0) {
00140     source->visual     = DIRECTCOLOR;
00141     TRACEMS2(cinfo, 1, JTRC_RLE, width, height);
00142   } else
00143     ERREXIT(cinfo, JERR_RLE_UNSUPPORTED);
00144   
00145   if (source->visual == GRAYSCALE || source->visual == MAPPEDGRAY) {
00146     cinfo->in_color_space   = JCS_GRAYSCALE;
00147     cinfo->input_components = 1;
00148   } else {
00149     cinfo->in_color_space   = JCS_RGB;
00150     cinfo->input_components = 3;
00151   }
00152 
00153   /*
00154    * A place to hold each scanline while it's converted.
00155    * (GRAYSCALE scanlines don't need converting)
00156    */
00157   if (source->visual != GRAYSCALE) {
00158     source->rle_row = (rle_pixel**) (*cinfo->mem->alloc_sarray)
00159       ((j_common_ptr) cinfo, JPOOL_IMAGE,
00160        (JDIMENSION) width, (JDIMENSION) cinfo->input_components);
00161   }
00162 
00163   /* request a virtual array to hold the image */
00164   source->image = (*cinfo->mem->request_virt_sarray)
00165     ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
00166      (JDIMENSION) (width * source->header.ncolors),
00167      (JDIMENSION) height, (JDIMENSION) 1);
00168 
00169 #ifdef PROGRESS_REPORT
00170   if (progress != NULL) {
00171     /* count file input as separate pass */
00172     progress->total_extra_passes++;
00173   }
00174 #endif
00175 
00176   source->pub.buffer_height = 1;
00177 }
00178 
00179 
00180 /*
00181  * Read one row of pixels.
00182  * Called only after load_image has read the image into the virtual array.
00183  * Used for GRAYSCALE, MAPPEDGRAY, TRUECOLOR, and DIRECTCOLOR images.
00184  */
00185 
00186 METHODDEF(JDIMENSION)
00187 get_rle_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00188 {
00189   rle_source_ptr source = (rle_source_ptr) sinfo;
00190 
00191   source->row--;
00192   source->pub.buffer = (*cinfo->mem->access_virt_sarray)
00193     ((j_common_ptr) cinfo, source->image, source->row, (JDIMENSION) 1, FALSE);
00194 
00195   return 1;
00196 }
00197 
00198 /*
00199  * Read one row of pixels.
00200  * Called only after load_image has read the image into the virtual array.
00201  * Used for PSEUDOCOLOR images.
00202  */
00203 
00204 METHODDEF(JDIMENSION)
00205 get_pseudocolor_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00206 {
00207   rle_source_ptr source = (rle_source_ptr) sinfo;
00208   JSAMPROW src_row, dest_row;
00209   JDIMENSION col;
00210   rle_map *colormap;
00211   int val;
00212 
00213   colormap = source->header.cmap;
00214   dest_row = source->pub.buffer[0];
00215   source->row--;
00216   src_row = * (*cinfo->mem->access_virt_sarray)
00217     ((j_common_ptr) cinfo, source->image, source->row, (JDIMENSION) 1, FALSE);
00218 
00219   for (col = cinfo->image_width; col > 0; col--) {
00220     val = GETJSAMPLE(*src_row++);
00221     *dest_row++ = (JSAMPLE) (colormap[val      ] >> 8);
00222     *dest_row++ = (JSAMPLE) (colormap[val + 256] >> 8);
00223     *dest_row++ = (JSAMPLE) (colormap[val + 512] >> 8);
00224   }
00225 
00226   return 1;
00227 }
00228 
00229 
00230 /*
00231  * Load the image into a virtual array.  We have to do this because RLE
00232  * files start at the lower left while the JPEG standard has them starting
00233  * in the upper left.  This is called the first time we want to get a row
00234  * of input.  What we do is load the RLE data into the array and then call
00235  * the appropriate routine to read one row from the array.  Before returning,
00236  * we set source->pub.get_pixel_rows so that subsequent calls go straight to
00237  * the appropriate row-reading routine.
00238  */
00239 
00240 METHODDEF(JDIMENSION)
00241 load_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00242 {
00243   rle_source_ptr source = (rle_source_ptr) sinfo;
00244   JDIMENSION row, col;
00245   JSAMPROW  scanline, red_ptr, green_ptr, blue_ptr;
00246   rle_pixel **rle_row;
00247   rle_map *colormap;
00248   char channel;
00249 #ifdef PROGRESS_REPORT
00250   cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
00251 #endif
00252 
00253   colormap = source->header.cmap;
00254   rle_row = source->rle_row;
00255 
00256   /* Read the RLE data into our virtual array.
00257    * We assume here that (a) rle_pixel is represented the same as JSAMPLE,
00258    * and (b) we are not on a machine where FAR pointers differ from regular.
00259    */
00260   RLE_CLR_BIT(source->header, RLE_ALPHA); /* don't read the alpha channel */
00261 
00262 #ifdef PROGRESS_REPORT
00263   if (progress != NULL) {
00264     progress->pub.pass_limit = cinfo->image_height;
00265     progress->pub.pass_counter = 0;
00266     (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
00267   }
00268 #endif
00269 
00270   switch (source->visual) {
00271 
00272   case GRAYSCALE:
00273   case PSEUDOCOLOR:
00274     for (row = 0; row < cinfo->image_height; row++) {
00275       rle_row = (rle_pixel **) (*cinfo->mem->access_virt_sarray)
00276          ((j_common_ptr) cinfo, source->image, row, (JDIMENSION) 1, TRUE);
00277       rle_getrow(&source->header, rle_row);
00278 #ifdef PROGRESS_REPORT
00279       if (progress != NULL) {
00280         progress->pub.pass_counter++;
00281         (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
00282       }
00283 #endif
00284     }
00285     break;
00286 
00287   case MAPPEDGRAY:
00288   case TRUECOLOR:
00289     for (row = 0; row < cinfo->image_height; row++) {
00290       scanline = * (*cinfo->mem->access_virt_sarray)
00291         ((j_common_ptr) cinfo, source->image, row, (JDIMENSION) 1, TRUE);
00292       rle_row = source->rle_row;
00293       rle_getrow(&source->header, rle_row);
00294 
00295       for (col = 0; col < cinfo->image_width; col++) {
00296         for (channel = 0; channel < source->header.ncolors; channel++) {
00297           *scanline++ = (JSAMPLE)
00298             (colormap[GETJSAMPLE(rle_row[channel][col]) + 256 * channel] >> 8);
00299         }
00300       }
00301 
00302 #ifdef PROGRESS_REPORT
00303       if (progress != NULL) {
00304         progress->pub.pass_counter++;
00305         (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
00306       }
00307 #endif
00308     }
00309     break;
00310 
00311   case DIRECTCOLOR:
00312     for (row = 0; row < cinfo->image_height; row++) {
00313       scanline = * (*cinfo->mem->access_virt_sarray)
00314         ((j_common_ptr) cinfo, source->image, row, (JDIMENSION) 1, TRUE);
00315       rle_getrow(&source->header, rle_row);
00316 
00317       red_ptr   = rle_row[0];
00318       green_ptr = rle_row[1];
00319       blue_ptr  = rle_row[2];
00320 
00321       for (col = cinfo->image_width; col > 0; col--) {
00322         *scanline++ = *red_ptr++;
00323         *scanline++ = *green_ptr++;
00324         *scanline++ = *blue_ptr++;
00325       }
00326 
00327 #ifdef PROGRESS_REPORT
00328       if (progress != NULL) {
00329         progress->pub.pass_counter++;
00330         (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
00331       }
00332 #endif
00333     }
00334   }
00335 
00336 #ifdef PROGRESS_REPORT
00337   if (progress != NULL)
00338     progress->completed_extra_passes++;
00339 #endif
00340 
00341   /* Set up to call proper row-extraction routine in future */
00342   if (source->visual == PSEUDOCOLOR) {
00343     source->pub.buffer = source->rle_row;
00344     source->pub.get_pixel_rows = get_pseudocolor_row;
00345   } else {
00346     source->pub.get_pixel_rows = get_rle_row;
00347   }
00348   source->row = cinfo->image_height;
00349 
00350   /* And fetch the topmost (bottommost) row */
00351   return (*source->pub.get_pixel_rows) (cinfo, sinfo);   
00352 }
00353 
00354 
00355 /*
00356  * Finish up at the end of the file.
00357  */
00358 
00359 METHODDEF(void)
00360 finish_input_rle (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00361 {
00362   /* no work */
00363 }
00364 
00365 
00366 /*
00367  * The module selection routine for RLE format input.
00368  */
00369 
00370 GLOBAL(cjpeg_source_ptr)
00371 jinit_read_rle (j_compress_ptr cinfo)
00372 {
00373   rle_source_ptr source;
00374 
00375   /* Create module interface object */
00376   source = (rle_source_ptr)
00377       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
00378                                   SIZEOF(rle_source_struct));
00379   /* Fill in method ptrs */
00380   source->pub.start_input = start_input_rle;
00381   source->pub.finish_input = finish_input_rle;
00382   source->pub.get_pixel_rows = load_image;
00383 
00384   return (cjpeg_source_ptr) source;
00385 }
00386 
00387 #endif /* RLE_SUPPORTED */