PageRenderTime 49ms CodeModel.GetById 17ms app.highlight 28ms RepoModel.GetById 1ms app.codeStats 0ms

/src/FreeImage/Source/LibJPEG/rdppm.c

https://bitbucket.org/cabalistic/ogredeps/
C | 459 lines | 293 code | 74 blank | 92 comment | 58 complexity | 6fb61dfd7b2443a15eb3952f1ab132eb MD5 | raw file
  1/*
  2 * rdppm.c
  3 *
  4 * Copyright (C) 1991-1997, Thomas G. Lane.
  5 * Modified 2009 by Bill Allombert, Guido Vollbeding.
  6 * This file is part of the Independent JPEG Group's software.
  7 * For conditions of distribution and use, see the accompanying README file.
  8 *
  9 * This file contains routines to read input images in PPM/PGM format.
 10 * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
 11 * The PBMPLUS library is NOT required to compile this software
 12 * (but it is highly useful as a set of PPM image manipulation programs).
 13 *
 14 * These routines may need modification for non-Unix environments or
 15 * specialized applications.  As they stand, they assume input from
 16 * an ordinary stdio stream.  They further assume that reading begins
 17 * at the start of the file; start_input may need work if the
 18 * user interface has already read some data (e.g., to determine that
 19 * the file is indeed PPM format).
 20 */
 21
 22#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */
 23
 24#ifdef PPM_SUPPORTED
 25
 26
 27/* Portions of this code are based on the PBMPLUS library, which is:
 28**
 29** Copyright (C) 1988 by Jef Poskanzer.
 30**
 31** Permission to use, copy, modify, and distribute this software and its
 32** documentation for any purpose and without fee is hereby granted, provided
 33** that the above copyright notice appear in all copies and that both that
 34** copyright notice and this permission notice appear in supporting
 35** documentation.  This software is provided "as is" without express or
 36** implied warranty.
 37*/
 38
 39
 40/* Macros to deal with unsigned chars as efficiently as compiler allows */
 41
 42#ifdef HAVE_UNSIGNED_CHAR
 43typedef unsigned char U_CHAR;
 44#define UCH(x)	((int) (x))
 45#else /* !HAVE_UNSIGNED_CHAR */
 46#ifdef CHAR_IS_UNSIGNED
 47typedef char U_CHAR;
 48#define UCH(x)	((int) (x))
 49#else
 50typedef char U_CHAR;
 51#define UCH(x)	((int) (x) & 0xFF)
 52#endif
 53#endif /* HAVE_UNSIGNED_CHAR */
 54
 55
 56#define	ReadOK(file,buffer,len)	(JFREAD(file,buffer,len) == ((size_t) (len)))
 57
 58
 59/*
 60 * On most systems, reading individual bytes with getc() is drastically less
 61 * efficient than buffering a row at a time with fread().  On PCs, we must
 62 * allocate the buffer in near data space, because we are assuming small-data
 63 * memory model, wherein fread() can't reach far memory.  If you need to
 64 * process very wide images on a PC, you might have to compile in large-memory
 65 * model, or else replace fread() with a getc() loop --- which will be much
 66 * slower.
 67 */
 68
 69
 70/* Private version of data source object */
 71
 72typedef struct {
 73  struct cjpeg_source_struct pub; /* public fields */
 74
 75  U_CHAR *iobuffer;		/* non-FAR pointer to I/O buffer */
 76  JSAMPROW pixrow;		/* FAR pointer to same */
 77  size_t buffer_width;		/* width of I/O buffer */
 78  JSAMPLE *rescale;		/* => maxval-remapping array, or NULL */
 79} ppm_source_struct;
 80
 81typedef ppm_source_struct * ppm_source_ptr;
 82
 83
 84LOCAL(int)
 85pbm_getc (FILE * infile)
 86/* Read next char, skipping over any comments */
 87/* A comment/newline sequence is returned as a newline */
 88{
 89  register int ch;
 90
 91  ch = getc(infile);
 92  if (ch == '#') {
 93    do {
 94      ch = getc(infile);
 95    } while (ch != '\n' && ch != EOF);
 96  }
 97  return ch;
 98}
 99
100
101LOCAL(unsigned int)
102read_pbm_integer (j_compress_ptr cinfo, FILE * infile)
103/* Read an unsigned decimal integer from the PPM file */
104/* Swallows one trailing character after the integer */
105/* Note that on a 16-bit-int machine, only values up to 64k can be read. */
106/* This should not be a problem in practice. */
107{
108  register int ch;
109  register unsigned int val;
110
111  /* Skip any leading whitespace */
112  do {
113    ch = pbm_getc(infile);
114    if (ch == EOF)
115      ERREXIT(cinfo, JERR_INPUT_EOF);
116  } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
117
118  if (ch < '0' || ch > '9')
119    ERREXIT(cinfo, JERR_PPM_NONNUMERIC);
120
121  val = ch - '0';
122  while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
123    val *= 10;
124    val += ch - '0';
125  }
126  return val;
127}
128
129
130/*
131 * Read one row of pixels.
132 *
133 * We provide several different versions depending on input file format.
134 * In all cases, input is scaled to the size of JSAMPLE.
135 *
136 * A really fast path is provided for reading byte/sample raw files with
137 * maxval = MAXJSAMPLE, which is the normal case for 8-bit data.
138 */
139
140
141METHODDEF(JDIMENSION)
142get_text_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
143/* This version is for reading text-format PGM files with any maxval */
144{
145  ppm_source_ptr source = (ppm_source_ptr) sinfo;
146  FILE * infile = source->pub.input_file;
147  register JSAMPROW ptr;
148  register JSAMPLE *rescale = source->rescale;
149  JDIMENSION col;
150
151  ptr = source->pub.buffer[0];
152  for (col = cinfo->image_width; col > 0; col--) {
153    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
154  }
155  return 1;
156}
157
158
159METHODDEF(JDIMENSION)
160get_text_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
161/* This version is for reading text-format PPM files with any maxval */
162{
163  ppm_source_ptr source = (ppm_source_ptr) sinfo;
164  FILE * infile = source->pub.input_file;
165  register JSAMPROW ptr;
166  register JSAMPLE *rescale = source->rescale;
167  JDIMENSION col;
168
169  ptr = source->pub.buffer[0];
170  for (col = cinfo->image_width; col > 0; col--) {
171    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
172    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
173    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
174  }
175  return 1;
176}
177
178
179METHODDEF(JDIMENSION)
180get_scaled_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
181/* This version is for reading raw-byte-format PGM files with any maxval */
182{
183  ppm_source_ptr source = (ppm_source_ptr) sinfo;
184  register JSAMPROW ptr;
185  register U_CHAR * bufferptr;
186  register JSAMPLE *rescale = source->rescale;
187  JDIMENSION col;
188
189  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
190    ERREXIT(cinfo, JERR_INPUT_EOF);
191  ptr = source->pub.buffer[0];
192  bufferptr = source->iobuffer;
193  for (col = cinfo->image_width; col > 0; col--) {
194    *ptr++ = rescale[UCH(*bufferptr++)];
195  }
196  return 1;
197}
198
199
200METHODDEF(JDIMENSION)
201get_scaled_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
202/* This version is for reading raw-byte-format PPM files with any maxval */
203{
204  ppm_source_ptr source = (ppm_source_ptr) sinfo;
205  register JSAMPROW ptr;
206  register U_CHAR * bufferptr;
207  register JSAMPLE *rescale = source->rescale;
208  JDIMENSION col;
209
210  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
211    ERREXIT(cinfo, JERR_INPUT_EOF);
212  ptr = source->pub.buffer[0];
213  bufferptr = source->iobuffer;
214  for (col = cinfo->image_width; col > 0; col--) {
215    *ptr++ = rescale[UCH(*bufferptr++)];
216    *ptr++ = rescale[UCH(*bufferptr++)];
217    *ptr++ = rescale[UCH(*bufferptr++)];
218  }
219  return 1;
220}
221
222
223METHODDEF(JDIMENSION)
224get_raw_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
225/* This version is for reading raw-byte-format files with maxval = MAXJSAMPLE.
226 * In this case we just read right into the JSAMPLE buffer!
227 * Note that same code works for PPM and PGM files.
228 */
229{
230  ppm_source_ptr source = (ppm_source_ptr) sinfo;
231
232  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
233    ERREXIT(cinfo, JERR_INPUT_EOF);
234  return 1;
235}
236
237
238METHODDEF(JDIMENSION)
239get_word_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
240/* This version is for reading raw-word-format PGM files with any maxval */
241{
242  ppm_source_ptr source = (ppm_source_ptr) sinfo;
243  register JSAMPROW ptr;
244  register U_CHAR * bufferptr;
245  register JSAMPLE *rescale = source->rescale;
246  JDIMENSION col;
247
248  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
249    ERREXIT(cinfo, JERR_INPUT_EOF);
250  ptr = source->pub.buffer[0];
251  bufferptr = source->iobuffer;
252  for (col = cinfo->image_width; col > 0; col--) {
253    register int temp;
254    temp  = UCH(*bufferptr++) << 8;
255    temp |= UCH(*bufferptr++);
256    *ptr++ = rescale[temp];
257  }
258  return 1;
259}
260
261
262METHODDEF(JDIMENSION)
263get_word_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
264/* This version is for reading raw-word-format PPM files with any maxval */
265{
266  ppm_source_ptr source = (ppm_source_ptr) sinfo;
267  register JSAMPROW ptr;
268  register U_CHAR * bufferptr;
269  register JSAMPLE *rescale = source->rescale;
270  JDIMENSION col;
271
272  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
273    ERREXIT(cinfo, JERR_INPUT_EOF);
274  ptr = source->pub.buffer[0];
275  bufferptr = source->iobuffer;
276  for (col = cinfo->image_width; col > 0; col--) {
277    register int temp;
278    temp  = UCH(*bufferptr++) << 8;
279    temp |= UCH(*bufferptr++);
280    *ptr++ = rescale[temp];
281    temp  = UCH(*bufferptr++) << 8;
282    temp |= UCH(*bufferptr++);
283    *ptr++ = rescale[temp];
284    temp  = UCH(*bufferptr++) << 8;
285    temp |= UCH(*bufferptr++);
286    *ptr++ = rescale[temp];
287  }
288  return 1;
289}
290
291
292/*
293 * Read the file header; return image size and component count.
294 */
295
296METHODDEF(void)
297start_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
298{
299  ppm_source_ptr source = (ppm_source_ptr) sinfo;
300  int c;
301  unsigned int w, h, maxval;
302  boolean need_iobuffer, use_raw_buffer, need_rescale;
303
304  if (getc(source->pub.input_file) != 'P')
305    ERREXIT(cinfo, JERR_PPM_NOT);
306
307  c = getc(source->pub.input_file); /* subformat discriminator character */
308
309  /* detect unsupported variants (ie, PBM) before trying to read header */
310  switch (c) {
311  case '2':			/* it's a text-format PGM file */
312  case '3':			/* it's a text-format PPM file */
313  case '5':			/* it's a raw-format PGM file */
314  case '6':			/* it's a raw-format PPM file */
315    break;
316  default:
317    ERREXIT(cinfo, JERR_PPM_NOT);
318    break;
319  }
320
321  /* fetch the remaining header info */
322  w = read_pbm_integer(cinfo, source->pub.input_file);
323  h = read_pbm_integer(cinfo, source->pub.input_file);
324  maxval = read_pbm_integer(cinfo, source->pub.input_file);
325
326  if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
327    ERREXIT(cinfo, JERR_PPM_NOT);
328
329  cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */
330  cinfo->image_width = (JDIMENSION) w;
331  cinfo->image_height = (JDIMENSION) h;
332
333  /* initialize flags to most common settings */
334  need_iobuffer = TRUE;		/* do we need an I/O buffer? */
335  use_raw_buffer = FALSE;	/* do we map input buffer onto I/O buffer? */
336  need_rescale = TRUE;		/* do we need a rescale array? */
337
338  switch (c) {
339  case '2':			/* it's a text-format PGM file */
340    cinfo->input_components = 1;
341    cinfo->in_color_space = JCS_GRAYSCALE;
342    TRACEMS2(cinfo, 1, JTRC_PGM_TEXT, w, h);
343    source->pub.get_pixel_rows = get_text_gray_row;
344    need_iobuffer = FALSE;
345    break;
346
347  case '3':			/* it's a text-format PPM file */
348    cinfo->input_components = 3;
349    cinfo->in_color_space = JCS_RGB;
350    TRACEMS2(cinfo, 1, JTRC_PPM_TEXT, w, h);
351    source->pub.get_pixel_rows = get_text_rgb_row;
352    need_iobuffer = FALSE;
353    break;
354
355  case '5':			/* it's a raw-format PGM file */
356    cinfo->input_components = 1;
357    cinfo->in_color_space = JCS_GRAYSCALE;
358    TRACEMS2(cinfo, 1, JTRC_PGM, w, h);
359    if (maxval > 255) {
360      source->pub.get_pixel_rows = get_word_gray_row;
361    } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
362      source->pub.get_pixel_rows = get_raw_row;
363      use_raw_buffer = TRUE;
364      need_rescale = FALSE;
365    } else {
366      source->pub.get_pixel_rows = get_scaled_gray_row;
367    }
368    break;
369
370  case '6':			/* it's a raw-format PPM file */
371    cinfo->input_components = 3;
372    cinfo->in_color_space = JCS_RGB;
373    TRACEMS2(cinfo, 1, JTRC_PPM, w, h);
374    if (maxval > 255) {
375      source->pub.get_pixel_rows = get_word_rgb_row;
376    } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
377      source->pub.get_pixel_rows = get_raw_row;
378      use_raw_buffer = TRUE;
379      need_rescale = FALSE;
380    } else {
381      source->pub.get_pixel_rows = get_scaled_rgb_row;
382    }
383    break;
384  }
385
386  /* Allocate space for I/O buffer: 1 or 3 bytes or words/pixel. */
387  if (need_iobuffer) {
388    source->buffer_width = (size_t) w * cinfo->input_components *
389      ((maxval<=255) ? SIZEOF(U_CHAR) : (2*SIZEOF(U_CHAR)));
390    source->iobuffer = (U_CHAR *)
391      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
392				  source->buffer_width);
393  }
394
395  /* Create compressor input buffer. */
396  if (use_raw_buffer) {
397    /* For unscaled raw-input case, we can just map it onto the I/O buffer. */
398    /* Synthesize a JSAMPARRAY pointer structure */
399    /* Cast here implies near->far pointer conversion on PCs */
400    source->pixrow = (JSAMPROW) source->iobuffer;
401    source->pub.buffer = & source->pixrow;
402    source->pub.buffer_height = 1;
403  } else {
404    /* Need to translate anyway, so make a separate sample buffer. */
405    source->pub.buffer = (*cinfo->mem->alloc_sarray)
406      ((j_common_ptr) cinfo, JPOOL_IMAGE,
407       (JDIMENSION) w * cinfo->input_components, (JDIMENSION) 1);
408    source->pub.buffer_height = 1;
409  }
410
411  /* Compute the rescaling array if required. */
412  if (need_rescale) {
413    INT32 val, half_maxval;
414
415    /* On 16-bit-int machines we have to be careful of maxval = 65535 */
416    source->rescale = (JSAMPLE *)
417      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
418				  (size_t) (((long) maxval + 1L) * SIZEOF(JSAMPLE)));
419    half_maxval = maxval / 2;
420    for (val = 0; val <= (INT32) maxval; val++) {
421      /* The multiplication here must be done in 32 bits to avoid overflow */
422      source->rescale[val] = (JSAMPLE) ((val*MAXJSAMPLE + half_maxval)/maxval);
423    }
424  }
425}
426
427
428/*
429 * Finish up at the end of the file.
430 */
431
432METHODDEF(void)
433finish_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
434{
435  /* no work */
436}
437
438
439/*
440 * The module selection routine for PPM format input.
441 */
442
443GLOBAL(cjpeg_source_ptr)
444jinit_read_ppm (j_compress_ptr cinfo)
445{
446  ppm_source_ptr source;
447
448  /* Create module interface object */
449  source = (ppm_source_ptr)
450      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
451				  SIZEOF(ppm_source_struct));
452  /* Fill in method ptrs, except get_pixel_rows which start_input sets */
453  source->pub.start_input = start_input_ppm;
454  source->pub.finish_input = finish_input_ppm;
455
456  return (cjpeg_source_ptr) source;
457}
458
459#endif /* PPM_SUPPORTED */