compiler/libjpeg/test/rdppm.c

   1 /*
   2     $Id$
   3 */
   4
   5 /*
   6  * rdppm.c
   7  *
   8  * Copyright (C) 1991-1997, Thomas G. Lane.
   9  * This file is part of the Independent JPEG Group's software.
  10  * For conditions of distribution and use, see the accompanying README file.
  11  *
  12  * This file contains routines to read input images in PPM/PGM format.
  13  * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
  14  * The PBMPLUS library is NOT required to compile this software
  15  * (but it is highly useful as a set of PPM image manipulation programs).
  16  *
  17  * These routines may need modification for non-Unix environments or
  18  * specialized applications.  As they stand, they assume input from
  19  * an ordinary stdio stream.  They further assume that reading begins
  20  * at the start of the file; start_input may need work if the
  21  * user interface has already read some data (e.g., to determine that
  22  * the file is indeed PPM format).
  23  */
  24
  25 #include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
  26
  27 #ifdef PPM_SUPPORTED
  28
  29
  30 /* Portions of this code are based on the PBMPLUS library, which is:
  31 **
  32 ** Copyright (C) 1988 by Jef Poskanzer.
  33 **
  34 ** Permission to use, copy, modify, and distribute this software and its
  35 ** documentation for any purpose and without fee is hereby granted, provided
  36 ** that the above copyright notice appear in all copies and that both that
  37 ** copyright notice and this permission notice appear in supporting
  38 ** documentation.  This software is provided "as is" without express or
  39 ** implied warranty.
  40 */
  41
  42
  43 /* Macros to deal with unsigned chars as efficiently as compiler allows */
  44
  45 #ifdef HAVE_UNSIGNED_CHAR
  46 typedef unsigned char U_CHAR;
  47 #define UCH(x)  ((int) (x))
  48 #else /* !HAVE_UNSIGNED_CHAR */
  49 #ifdef CHAR_IS_UNSIGNED
  50 typedef char U_CHAR;
  51 #define UCH(x)  ((int) (x))
  52 #else
  53 typedef char U_CHAR;
  54 #define UCH(x)  ((int) (x) & 0xFF)
  55 #endif
  56 #endif /* HAVE_UNSIGNED_CHAR */
  57
  58
  59 #define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
  60
  61
  62 /*
  63  * On most systems, reading individual bytes with getc() is drastically less
  64  * efficient than buffering a row at a time with fread().  On PCs, we must
  65  * allocate the buffer in near data space, because we are assuming small-data
  66  * memory model, wherein fread() can't reach far memory.  If you need to
  67  * process very wide images on a PC, you might have to compile in large-memory
  68  * model, or else replace fread() with a getc() loop --- which will be much
  69  * slower.
  70  */
  71
  72
  73 /* Private version of data source object */
  74
  75 typedef struct {
  76   struct cjpeg_source_struct pub; /* public fields */
  77
  78   U_CHAR *iobuffer;             /* non-FAR pointer to I/O buffer */
  79   JSAMPROW pixrow;              /* FAR pointer to same */
  80   size_t buffer_width;          /* width of I/O buffer */
  81   JSAMPLE *rescale;             /* => maxval-remapping array, or NULL */
  82 } ppm_source_struct;
  83
  84 typedef ppm_source_struct * ppm_source_ptr;
  85
  86
  87 LOCAL(int)
  88 pbm_getc (FILE * infile)
  89 /* Read next char, skipping over any comments */
  90 /* A comment/newline sequence is returned as a newline */
  91 {
  92   register int ch;
  93
  94   ch = getc(infile);
  95   if (ch == '#') {
  96     do {
  97       ch = getc(infile);
  98     } while (ch != '\n' && ch != EOF);
  99   }
 100   return ch;
 101 }
 102
 103
 104 LOCAL(unsigned int)
 105 read_pbm_integer (j_compress_ptr cinfo, FILE * infile)
 106 /* Read an unsigned decimal integer from the PPM file */
 107 /* Swallows one trailing character after the integer */
 108 /* Note that on a 16-bit-int machine, only values up to 64k can be read. */
 109 /* This should not be a problem in practice. */
 110 {
 111   register int ch;
 112   register unsigned int val;
 113
 114   /* Skip any leading whitespace */
 115   do {
 116     ch = pbm_getc(infile);
 117     if (ch == EOF)
 118       ERREXIT(cinfo, JERR_INPUT_EOF);
 119   } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
 120
 121   if (ch < '0' || ch > '9')
 122     ERREXIT(cinfo, JERR_PPM_NONNUMERIC);
 123
 124   val = ch - '0';
 125   while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
 126     val *= 10;
 127     val += ch - '0';
 128   }
 129   return val;
 130 }
 131
 132
 133 /*
 134  * Read one row of pixels.
 135  *
 136  * We provide several different versions depending on input file format.
 137  * In all cases, input is scaled to the size of JSAMPLE.
 138  *
 139  * A really fast path is provided for reading byte/sample raw files with
 140  * maxval = MAXJSAMPLE, which is the normal case for 8-bit data.
 141  */
 142
 143
 144 METHODDEF(JDIMENSION)
 145 get_text_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 146 /* This version is for reading text-format PGM files with any maxval */
 147 {
 148   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 149   FILE * infile = source->pub.input_file;
 150   register JSAMPROW ptr;
 151   register JSAMPLE *rescale = source->rescale;
 152   JDIMENSION col;
 153
 154   ptr = source->pub.buffer[0];
 155   for (col = cinfo->image_width; col > 0; col--) {
 156     *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
 157   }
 158   return 1;
 159 }
 160
 161
 162 METHODDEF(JDIMENSION)
 163 get_text_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 164 /* This version is for reading text-format PPM files with any maxval */
 165 {
 166   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 167   FILE * infile = source->pub.input_file;
 168   register JSAMPROW ptr;
 169   register JSAMPLE *rescale = source->rescale;
 170   JDIMENSION col;
 171
 172   ptr = source->pub.buffer[0];
 173   for (col = cinfo->image_width; col > 0; col--) {
 174     *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
 175     *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
 176     *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
 177   }
 178   return 1;
 179 }
 180
 181
 182 METHODDEF(JDIMENSION)
 183 get_scaled_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 184 /* This version is for reading raw-byte-format PGM files with any maxval */
 185 {
 186   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 187   register JSAMPROW ptr;
 188   register U_CHAR * bufferptr;
 189   register JSAMPLE *rescale = source->rescale;
 190   JDIMENSION col;
 191
 192   if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
 193     ERREXIT(cinfo, JERR_INPUT_EOF);
 194   ptr = source->pub.buffer[0];
 195   bufferptr = source->iobuffer;
 196   for (col = cinfo->image_width; col > 0; col--) {
 197     *ptr++ = rescale[UCH(*bufferptr++)];
 198   }
 199   return 1;
 200 }
 201
 202
 203 METHODDEF(JDIMENSION)
 204 get_scaled_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 205 /* This version is for reading raw-byte-format PPM files with any maxval */
 206 {
 207   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 208   register JSAMPROW ptr;
 209   register U_CHAR * bufferptr;
 210   register JSAMPLE *rescale = source->rescale;
 211   JDIMENSION col;
 212
 213   if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
 214     ERREXIT(cinfo, JERR_INPUT_EOF);
 215   ptr = source->pub.buffer[0];
 216   bufferptr = source->iobuffer;
 217   for (col = cinfo->image_width; col > 0; col--) {
 218     *ptr++ = rescale[UCH(*bufferptr++)];
 219     *ptr++ = rescale[UCH(*bufferptr++)];
 220     *ptr++ = rescale[UCH(*bufferptr++)];
 221   }
 222   return 1;
 223 }
 224
 225
 226 METHODDEF(JDIMENSION)
 227 get_raw_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 228 /* This version is for reading raw-byte-format files with maxval = MAXJSAMPLE.
 229  * In this case we just read right into the JSAMPLE buffer!
 230  * Note that same code works for PPM and PGM files.
 231  */
 232 {
 233   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 234
 235   if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
 236     ERREXIT(cinfo, JERR_INPUT_EOF);
 237   return 1;
 238 }
 239
 240
 241 METHODDEF(JDIMENSION)
 242 get_word_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 243 /* This version is for reading raw-word-format PGM files with any maxval */
 244 {
 245   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 246   register JSAMPROW ptr;
 247   register U_CHAR * bufferptr;
 248   register JSAMPLE *rescale = source->rescale;
 249   JDIMENSION col;
 250
 251   if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
 252     ERREXIT(cinfo, JERR_INPUT_EOF);
 253   ptr = source->pub.buffer[0];
 254   bufferptr = source->iobuffer;
 255   for (col = cinfo->image_width; col > 0; col--) {
 256     register int temp;
 257     temp  = UCH(*bufferptr++);
 258     temp |= UCH(*bufferptr++) << 8;
 259     *ptr++ = rescale[temp];
 260   }
 261   return 1;
 262 }
 263
 264
 265 METHODDEF(JDIMENSION)
 266 get_word_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 267 /* This version is for reading raw-word-format PPM files with any maxval */
 268 {
 269   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 270   register JSAMPROW ptr;
 271   register U_CHAR * bufferptr;
 272   register JSAMPLE *rescale = source->rescale;
 273   JDIMENSION col;
 274
 275   if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
 276     ERREXIT(cinfo, JERR_INPUT_EOF);
 277   ptr = source->pub.buffer[0];
 278   bufferptr = source->iobuffer;
 279   for (col = cinfo->image_width; col > 0; col--) {
 280     register int temp;
 281     temp  = UCH(*bufferptr++);
 282     temp |= UCH(*bufferptr++) << 8;
 283     *ptr++ = rescale[temp];
 284     temp  = UCH(*bufferptr++);
 285     temp |= UCH(*bufferptr++) << 8;
 286     *ptr++ = rescale[temp];
 287     temp  = UCH(*bufferptr++);
 288     temp |= UCH(*bufferptr++) << 8;
 289     *ptr++ = rescale[temp];
 290   }
 291   return 1;
 292 }
 293
 294
 295 /*
 296  * Read the file header; return image size and component count.
 297  */
 298
 299 METHODDEF(void)
 300 start_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 301 {
 302   ppm_source_ptr source = (ppm_source_ptr) sinfo;
 303   int c;
 304   unsigned int w, h, maxval;
 305   boolean need_iobuffer, use_raw_buffer, need_rescale;
 306
 307   if (getc(source->pub.input_file) != 'P')
 308     ERREXIT(cinfo, JERR_PPM_NOT);
 309
 310   c = getc(source->pub.input_file); /* subformat discriminator character */
 311
 312   /* detect unsupported variants (ie, PBM) before trying to read header */
 313   switch (c) {
 314   case '2':                     /* it's a text-format PGM file */
 315   case '3':                     /* it's a text-format PPM file */
 316   case '5':                     /* it's a raw-format PGM file */
 317   case '6':                     /* it's a raw-format PPM file */
 318     break;
 319   default:
 320     ERREXIT(cinfo, JERR_PPM_NOT);
 321     break;
 322   }
 323
 324   /* fetch the remaining header info */
 325   w = read_pbm_integer(cinfo, source->pub.input_file);
 326   h = read_pbm_integer(cinfo, source->pub.input_file);
 327   maxval = read_pbm_integer(cinfo, source->pub.input_file);
 328
 329   if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
 330     ERREXIT(cinfo, JERR_PPM_NOT);
 331
 332   cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */
 333   cinfo->image_width = (JDIMENSION) w;
 334   cinfo->image_height = (JDIMENSION) h;
 335
 336   /* initialize flags to most common settings */
 337   need_iobuffer = TRUE;         /* do we need an I/O buffer? */
 338   use_raw_buffer = FALSE;       /* do we map input buffer onto I/O buffer? */
 339   need_rescale = TRUE;          /* do we need a rescale array? */
 340
 341   switch (c) {
 342   case '2':                     /* it's a text-format PGM file */
 343     cinfo->input_components = 1;
 344     cinfo->in_color_space = JCS_GRAYSCALE;
 345     TRACEMS2(cinfo, 1, JTRC_PGM_TEXT, w, h);
 346     source->pub.get_pixel_rows = get_text_gray_row;
 347     need_iobuffer = FALSE;
 348     break;
 349
 350   case '3':                     /* it's a text-format PPM file */
 351     cinfo->input_components = 3;
 352     cinfo->in_color_space = JCS_RGB;
 353     TRACEMS2(cinfo, 1, JTRC_PPM_TEXT, w, h);
 354     source->pub.get_pixel_rows = get_text_rgb_row;
 355     need_iobuffer = FALSE;
 356     break;
 357
 358   case '5':                     /* it's a raw-format PGM file */
 359     cinfo->input_components = 1;
 360     cinfo->in_color_space = JCS_GRAYSCALE;
 361     TRACEMS2(cinfo, 1, JTRC_PGM, w, h);
 362     if (maxval > 255) {
 363       source->pub.get_pixel_rows = get_word_gray_row;
 364     } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
 365       source->pub.get_pixel_rows = get_raw_row;
 366       use_raw_buffer = TRUE;
 367       need_rescale = FALSE;
 368     } else {
 369       source->pub.get_pixel_rows = get_scaled_gray_row;
 370     }
 371     break;
 372
 373   case '6':                     /* it's a raw-format PPM file */
 374     cinfo->input_components = 3;
 375     cinfo->in_color_space = JCS_RGB;
 376     TRACEMS2(cinfo, 1, JTRC_PPM, w, h);
 377     if (maxval > 255) {
 378       source->pub.get_pixel_rows = get_word_rgb_row;
 379     } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
 380       source->pub.get_pixel_rows = get_raw_row;
 381       use_raw_buffer = TRUE;
 382       need_rescale = FALSE;
 383     } else {
 384       source->pub.get_pixel_rows = get_scaled_rgb_row;
 385     }
 386     break;
 387   }
 388
 389   /* Allocate space for I/O buffer: 1 or 3 bytes or words/pixel. */
 390   if (need_iobuffer) {
 391     source->buffer_width = (size_t) w * cinfo->input_components *
 392       ((maxval<=255) ? SIZEOF(U_CHAR) : (2*SIZEOF(U_CHAR)));
 393     source->iobuffer = (U_CHAR *)
 394       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 395                                   source->buffer_width);
 396   }
 397
 398   /* Create compressor input buffer. */
 399   if (use_raw_buffer) {
 400     /* For unscaled raw-input case, we can just map it onto the I/O buffer. */
 401     /* Synthesize a JSAMPARRAY pointer structure */
 402     /* Cast here implies near->far pointer conversion on PCs */
 403     source->pixrow = (JSAMPROW) source->iobuffer;
 404     source->pub.buffer = & source->pixrow;
 405     source->pub.buffer_height = 1;
 406   } else {
 407     /* Need to translate anyway, so make a separate sample buffer. */
 408     source->pub.buffer = (*cinfo->mem->alloc_sarray)
 409       ((j_common_ptr) cinfo, JPOOL_IMAGE,
 410        (JDIMENSION) w * cinfo->input_components, (JDIMENSION) 1);
 411     source->pub.buffer_height = 1;
 412   }
 413
 414   /* Compute the rescaling array if required. */
 415   if (need_rescale) {
 416     INT32 val, half_maxval;
 417
 418     /* On 16-bit-int machines we have to be careful of maxval = 65535 */
 419     source->rescale = (JSAMPLE *)
 420       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 421                                   (size_t) (((long) maxval + 1L) * SIZEOF(JSAMPLE)));
 422     half_maxval = maxval / 2;
 423     for (val = 0; val <= (INT32) maxval; val++) {
 424       /* The multiplication here must be done in 32 bits to avoid overflow */
 425       source->rescale[val] = (JSAMPLE) ((val*MAXJSAMPLE + half_maxval)/maxval);
 426     }
 427   }
 428 }
 429
 430
 431 /*
 432  * Finish up at the end of the file.
 433  */
 434
 435 METHODDEF(void)
 436 finish_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 437 {
 438   /* no work */
 439 }
 440
 441
 442 /*
 443  * The module selection routine for PPM format input.
 444  */
 445
 446 JGLOBAL(cjpeg_source_ptr)
 447 jinit_read_ppm (j_compress_ptr cinfo)
 448 {
 449   ppm_source_ptr source;
 450
 451   /* Create module interface object */
 452   source = (ppm_source_ptr)
 453       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 454                                   SIZEOF(ppm_source_struct));
 455   /* Fill in method ptrs, except get_pixel_rows which start_input sets */
 456   source->pub.start_input = start_input_ppm;
 457   source->pub.finish_input = finish_input_ppm;
 458
 459   return (cjpeg_source_ptr) source;
 460 }
 461
 462 #endif /* PPM_SUPPORTED */