source: trunk/libjpeg/rdppm.c @ 15

Last change on this file since 15 was 15, checked in by Eugene Romanenko, 16 years ago

needed libs update

File size: 14.1 KB
Line 
1/*
2 * rdppm.c
3 *
4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file contains routines to read input images in PPM/PGM format.
9 * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
10 * The PBMPLUS library is NOT required to compile this software
11 * (but it is highly useful as a set of PPM image manipulation programs).
12 *
13 * These routines may need modification for non-Unix environments or
14 * specialized applications.  As they stand, they assume input from
15 * an ordinary stdio stream.  They further assume that reading begins
16 * at the start of the file; start_input may need work if the
17 * user interface has already read some data (e.g., to determine that
18 * the file is indeed PPM format).
19 */
20
21#include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
22
23#ifdef PPM_SUPPORTED
24
25
26/* Portions of this code are based on the PBMPLUS library, which is:
27**
28** Copyright (C) 1988 by Jef Poskanzer.
29**
30** Permission to use, copy, modify, and distribute this software and its
31** documentation for any purpose and without fee is hereby granted, provided
32** that the above copyright notice appear in all copies and that both that
33** copyright notice and this permission notice appear in supporting
34** documentation.  This software is provided "as is" without express or
35** implied warranty.
36*/
37
38
39/* Macros to deal with unsigned chars as efficiently as compiler allows */
40
41#ifdef HAVE_UNSIGNED_CHAR
42typedef unsigned char U_CHAR;
43#define UCH(x)  ((int) (x))
44#else /* !HAVE_UNSIGNED_CHAR */
45#ifdef CHAR_IS_UNSIGNED
46typedef char U_CHAR;
47#define UCH(x)  ((int) (x))
48#else
49typedef char U_CHAR;
50#define UCH(x)  ((int) (x) & 0xFF)
51#endif
52#endif /* HAVE_UNSIGNED_CHAR */
53
54
55#define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
56
57
58/*
59 * On most systems, reading individual bytes with getc() is drastically less
60 * efficient than buffering a row at a time with fread().  On PCs, we must
61 * allocate the buffer in near data space, because we are assuming small-data
62 * memory model, wherein fread() can't reach far memory.  If you need to
63 * process very wide images on a PC, you might have to compile in large-memory
64 * model, or else replace fread() with a getc() loop --- which will be much
65 * slower.
66 */
67
68
69/* Private version of data source object */
70
71typedef struct {
72  struct cjpeg_source_struct pub; /* public fields */
73
74  U_CHAR *iobuffer;             /* non-FAR pointer to I/O buffer */
75  JSAMPROW pixrow;              /* FAR pointer to same */
76  size_t buffer_width;          /* width of I/O buffer */
77  JSAMPLE *rescale;             /* => maxval-remapping array, or NULL */
78} ppm_source_struct;
79
80typedef ppm_source_struct * ppm_source_ptr;
81
82
83LOCAL(int)
84pbm_getc (FILE * infile)
85/* Read next char, skipping over any comments */
86/* A comment/newline sequence is returned as a newline */
87{
88  register int ch;
89
90  ch = getc(infile);
91  if (ch == '#') {
92    do {
93      ch = getc(infile);
94    } while (ch != '\n' && ch != EOF);
95  }
96  return ch;
97}
98
99
100LOCAL(unsigned int)
101read_pbm_integer (j_compress_ptr cinfo, FILE * infile)
102/* Read an unsigned decimal integer from the PPM file */
103/* Swallows one trailing character after the integer */
104/* Note that on a 16-bit-int machine, only values up to 64k can be read. */
105/* This should not be a problem in practice. */
106{
107  register int ch;
108  register unsigned int val;
109
110  /* Skip any leading whitespace */
111  do {
112    ch = pbm_getc(infile);
113    if (ch == EOF)
114      ERREXIT(cinfo, JERR_INPUT_EOF);
115  } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
116
117  if (ch < '0' || ch > '9')
118    ERREXIT(cinfo, JERR_PPM_NONNUMERIC);
119
120  val = ch - '0';
121  while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
122    val *= 10;
123    val += ch - '0';
124  }
125  return val;
126}
127
128
129/*
130 * Read one row of pixels.
131 *
132 * We provide several different versions depending on input file format.
133 * In all cases, input is scaled to the size of JSAMPLE.
134 *
135 * A really fast path is provided for reading byte/sample raw files with
136 * maxval = MAXJSAMPLE, which is the normal case for 8-bit data.
137 */
138
139
140METHODDEF(JDIMENSION)
141get_text_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
142/* This version is for reading text-format PGM files with any maxval */
143{
144  ppm_source_ptr source = (ppm_source_ptr) sinfo;
145  FILE * infile = source->pub.input_file;
146  register JSAMPROW ptr;
147  register JSAMPLE *rescale = source->rescale;
148  JDIMENSION col;
149
150  ptr = source->pub.buffer[0];
151  for (col = cinfo->image_width; col > 0; col--) {
152    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
153  }
154  return 1;
155}
156
157
158METHODDEF(JDIMENSION)
159get_text_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
160/* This version is for reading text-format PPM files with any maxval */
161{
162  ppm_source_ptr source = (ppm_source_ptr) sinfo;
163  FILE * infile = source->pub.input_file;
164  register JSAMPROW ptr;
165  register JSAMPLE *rescale = source->rescale;
166  JDIMENSION col;
167
168  ptr = source->pub.buffer[0];
169  for (col = cinfo->image_width; col > 0; col--) {
170    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
171    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
172    *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
173  }
174  return 1;
175}
176
177
178METHODDEF(JDIMENSION)
179get_scaled_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
180/* This version is for reading raw-byte-format PGM files with any maxval */
181{
182  ppm_source_ptr source = (ppm_source_ptr) sinfo;
183  register JSAMPROW ptr;
184  register U_CHAR * bufferptr;
185  register JSAMPLE *rescale = source->rescale;
186  JDIMENSION col;
187
188  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
189    ERREXIT(cinfo, JERR_INPUT_EOF);
190  ptr = source->pub.buffer[0];
191  bufferptr = source->iobuffer;
192  for (col = cinfo->image_width; col > 0; col--) {
193    *ptr++ = rescale[UCH(*bufferptr++)];
194  }
195  return 1;
196}
197
198
199METHODDEF(JDIMENSION)
200get_scaled_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
201/* This version is for reading raw-byte-format PPM files with any maxval */
202{
203  ppm_source_ptr source = (ppm_source_ptr) sinfo;
204  register JSAMPROW ptr;
205  register U_CHAR * bufferptr;
206  register JSAMPLE *rescale = source->rescale;
207  JDIMENSION col;
208
209  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
210    ERREXIT(cinfo, JERR_INPUT_EOF);
211  ptr = source->pub.buffer[0];
212  bufferptr = source->iobuffer;
213  for (col = cinfo->image_width; col > 0; col--) {
214    *ptr++ = rescale[UCH(*bufferptr++)];
215    *ptr++ = rescale[UCH(*bufferptr++)];
216    *ptr++ = rescale[UCH(*bufferptr++)];
217  }
218  return 1;
219}
220
221
222METHODDEF(JDIMENSION)
223get_raw_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
224/* This version is for reading raw-byte-format files with maxval = MAXJSAMPLE.
225 * In this case we just read right into the JSAMPLE buffer!
226 * Note that same code works for PPM and PGM files.
227 */
228{
229  ppm_source_ptr source = (ppm_source_ptr) sinfo;
230
231  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
232    ERREXIT(cinfo, JERR_INPUT_EOF);
233  return 1;
234}
235
236
237METHODDEF(JDIMENSION)
238get_word_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
239/* This version is for reading raw-word-format PGM files with any maxval */
240{
241  ppm_source_ptr source = (ppm_source_ptr) sinfo;
242  register JSAMPROW ptr;
243  register U_CHAR * bufferptr;
244  register JSAMPLE *rescale = source->rescale;
245  JDIMENSION col;
246
247  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
248    ERREXIT(cinfo, JERR_INPUT_EOF);
249  ptr = source->pub.buffer[0];
250  bufferptr = source->iobuffer;
251  for (col = cinfo->image_width; col > 0; col--) {
252    register int temp;
253    temp  = UCH(*bufferptr++);
254    temp |= UCH(*bufferptr++) << 8;
255    *ptr++ = rescale[temp];
256  }
257  return 1;
258}
259
260
261METHODDEF(JDIMENSION)
262get_word_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
263/* This version is for reading raw-word-format PPM files with any maxval */
264{
265  ppm_source_ptr source = (ppm_source_ptr) sinfo;
266  register JSAMPROW ptr;
267  register U_CHAR * bufferptr;
268  register JSAMPLE *rescale = source->rescale;
269  JDIMENSION col;
270
271  if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
272    ERREXIT(cinfo, JERR_INPUT_EOF);
273  ptr = source->pub.buffer[0];
274  bufferptr = source->iobuffer;
275  for (col = cinfo->image_width; col > 0; col--) {
276    register int temp;
277    temp  = UCH(*bufferptr++);
278    temp |= UCH(*bufferptr++) << 8;
279    *ptr++ = rescale[temp];
280    temp  = UCH(*bufferptr++);
281    temp |= UCH(*bufferptr++) << 8;
282    *ptr++ = rescale[temp];
283    temp  = UCH(*bufferptr++);
284    temp |= UCH(*bufferptr++) << 8;
285    *ptr++ = rescale[temp];
286  }
287  return 1;
288}
289
290
291/*
292 * Read the file header; return image size and component count.
293 */
294
295METHODDEF(void)
296start_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
297{
298  ppm_source_ptr source = (ppm_source_ptr) sinfo;
299  int c;
300  unsigned int w, h, maxval;
301  boolean need_iobuffer, use_raw_buffer, need_rescale;
302
303  if (getc(source->pub.input_file) != 'P')
304    ERREXIT(cinfo, JERR_PPM_NOT);
305
306  c = getc(source->pub.input_file); /* subformat discriminator character */
307
308  /* detect unsupported variants (ie, PBM) before trying to read header */
309  switch (c) {
310  case '2':                     /* it's a text-format PGM file */
311  case '3':                     /* it's a text-format PPM file */
312  case '5':                     /* it's a raw-format PGM file */
313  case '6':                     /* it's a raw-format PPM file */
314    break;
315  default:
316    ERREXIT(cinfo, JERR_PPM_NOT);
317    break;
318  }
319
320  /* fetch the remaining header info */
321  w = read_pbm_integer(cinfo, source->pub.input_file);
322  h = read_pbm_integer(cinfo, source->pub.input_file);
323  maxval = read_pbm_integer(cinfo, source->pub.input_file);
324
325  if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
326    ERREXIT(cinfo, JERR_PPM_NOT);
327
328  cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */
329  cinfo->image_width = (JDIMENSION) w;
330  cinfo->image_height = (JDIMENSION) h;
331
332  /* initialize flags to most common settings */
333  need_iobuffer = TRUE;         /* do we need an I/O buffer? */
334  use_raw_buffer = FALSE;       /* do we map input buffer onto I/O buffer? */
335  need_rescale = TRUE;          /* do we need a rescale array? */
336
337  switch (c) {
338  case '2':                     /* it's a text-format PGM file */
339    cinfo->input_components = 1;
340    cinfo->in_color_space = JCS_GRAYSCALE;
341    TRACEMS2(cinfo, 1, JTRC_PGM_TEXT, w, h);
342    source->pub.get_pixel_rows = get_text_gray_row;
343    need_iobuffer = FALSE;
344    break;
345
346  case '3':                     /* it's a text-format PPM file */
347    cinfo->input_components = 3;
348    cinfo->in_color_space = JCS_RGB;
349    TRACEMS2(cinfo, 1, JTRC_PPM_TEXT, w, h);
350    source->pub.get_pixel_rows = get_text_rgb_row;
351    need_iobuffer = FALSE;
352    break;
353
354  case '5':                     /* it's a raw-format PGM file */
355    cinfo->input_components = 1;
356    cinfo->in_color_space = JCS_GRAYSCALE;
357    TRACEMS2(cinfo, 1, JTRC_PGM, w, h);
358    if (maxval > 255) {
359      source->pub.get_pixel_rows = get_word_gray_row;
360    } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
361      source->pub.get_pixel_rows = get_raw_row;
362      use_raw_buffer = TRUE;
363      need_rescale = FALSE;
364    } else {
365      source->pub.get_pixel_rows = get_scaled_gray_row;
366    }
367    break;
368
369  case '6':                     /* it's a raw-format PPM file */
370    cinfo->input_components = 3;
371    cinfo->in_color_space = JCS_RGB;
372    TRACEMS2(cinfo, 1, JTRC_PPM, w, h);
373    if (maxval > 255) {
374      source->pub.get_pixel_rows = get_word_rgb_row;
375    } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
376      source->pub.get_pixel_rows = get_raw_row;
377      use_raw_buffer = TRUE;
378      need_rescale = FALSE;
379    } else {
380      source->pub.get_pixel_rows = get_scaled_rgb_row;
381    }
382    break;
383  }
384
385  /* Allocate space for I/O buffer: 1 or 3 bytes or words/pixel. */
386  if (need_iobuffer) {
387    source->buffer_width = (size_t) w * cinfo->input_components *
388      ((maxval<=255) ? SIZEOF(U_CHAR) : (2*SIZEOF(U_CHAR)));
389    source->iobuffer = (U_CHAR *)
390      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
391                                  source->buffer_width);
392  }
393
394  /* Create compressor input buffer. */
395  if (use_raw_buffer) {
396    /* For unscaled raw-input case, we can just map it onto the I/O buffer. */
397    /* Synthesize a JSAMPARRAY pointer structure */
398    /* Cast here implies near->far pointer conversion on PCs */
399    source->pixrow = (JSAMPROW) source->iobuffer;
400    source->pub.buffer = & source->pixrow;
401    source->pub.buffer_height = 1;
402  } else {
403    /* Need to translate anyway, so make a separate sample buffer. */
404    source->pub.buffer = (*cinfo->mem->alloc_sarray)
405      ((j_common_ptr) cinfo, JPOOL_IMAGE,
406       (JDIMENSION) w * cinfo->input_components, (JDIMENSION) 1);
407    source->pub.buffer_height = 1;
408  }
409
410  /* Compute the rescaling array if required. */
411  if (need_rescale) {
412    INT32 val, half_maxval;
413
414    /* On 16-bit-int machines we have to be careful of maxval = 65535 */
415    source->rescale = (JSAMPLE *)
416      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
417                                  (size_t) (((long) maxval + 1L) * SIZEOF(JSAMPLE)));
418    half_maxval = maxval / 2;
419    for (val = 0; val <= (INT32) maxval; val++) {
420      /* The multiplication here must be done in 32 bits to avoid overflow */
421      source->rescale[val] = (JSAMPLE) ((val*MAXJSAMPLE + half_maxval)/maxval);
422    }
423  }
424}
425
426
427/*
428 * Finish up at the end of the file.
429 */
430
431METHODDEF(void)
432finish_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
433{
434  /* no work */
435}
436
437
438/*
439 * The module selection routine for PPM format input.
440 */
441
442GLOBAL(cjpeg_source_ptr)
443jinit_read_ppm (j_compress_ptr cinfo)
444{
445  ppm_source_ptr source;
446
447  /* Create module interface object */
448  source = (ppm_source_ptr)
449      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
450                                  SIZEOF(ppm_source_struct));
451  /* Fill in method ptrs, except get_pixel_rows which start_input sets */
452  source->pub.start_input = start_input_ppm;
453  source->pub.finish_input = finish_input_ppm;
454
455  return (cjpeg_source_ptr) source;
456}
457
458#endif /* PPM_SUPPORTED */
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