Details | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
6417 | ashmew2 | 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 |
||
42 | typedef unsigned char U_CHAR; |
||
43 | #define UCH(x) ((int) (x)) |
||
44 | #else /* !HAVE_UNSIGNED_CHAR */ |
||
45 | #ifdef CHAR_IS_UNSIGNED |
||
46 | typedef char U_CHAR; |
||
47 | #define UCH(x) ((int) (x)) |
||
48 | #else |
||
49 | typedef 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 | |||
71 | typedef 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 | |||
80 | typedef ppm_source_struct * ppm_source_ptr; |
||
81 | |||
82 | |||
83 | LOCAL(int) |
||
84 | pbm_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 | |||
100 | LOCAL(unsigned int) |
||
101 | read_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 | |||
140 | METHODDEF(JDIMENSION) |
||
141 | get_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 | |||
158 | METHODDEF(JDIMENSION) |
||
159 | get_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 | |||
178 | METHODDEF(JDIMENSION) |
||
179 | get_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 | |||
199 | METHODDEF(JDIMENSION) |
||
200 | get_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 | |||
222 | METHODDEF(JDIMENSION) |
||
223 | get_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 | |||
237 | METHODDEF(JDIMENSION) |
||
238 | get_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 | |||
261 | METHODDEF(JDIMENSION) |
||
262 | get_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 | |||
295 | METHODDEF(void) |
||
296 | start_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 | |||
431 | METHODDEF(void) |
||
432 | finish_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 | |||
442 | GLOBAL(cjpeg_source_ptr) |
||
443 | jinit_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 */=>=255)>=>=>=>><>><>><>><>=>> |