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comparison mupdf-source/thirdparty/libjpeg/rdtarga.c @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * rdtarga.c
3 *
4 * Copyright (C) 1991-1996, Thomas G. Lane.
5 * Modified 2017-2019 by 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 Targa format.
10 *
11 * These routines may need modification for non-Unix environments or
12 * specialized applications. As they stand, they assume input from
13 * an ordinary stdio stream. They further assume that reading begins
14 * at the start of the file; start_input may need work if the
15 * user interface has already read some data (e.g., to determine that
16 * the file is indeed Targa format).
17 *
18 * Based on code contributed by Lee Daniel Crocker.
19 */
20
21 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
22
23 #ifdef TARGA_SUPPORTED
24
25
26 /* Macros to deal with unsigned chars as efficiently as compiler allows */
27
28 #ifdef HAVE_UNSIGNED_CHAR
29 typedef unsigned char U_CHAR;
30 #define UCH(x) ((int) (x))
31 #else /* !HAVE_UNSIGNED_CHAR */
32 typedef char U_CHAR;
33 #ifdef CHAR_IS_UNSIGNED
34 #define UCH(x) ((int) (x))
35 #else
36 #define UCH(x) ((int) (x) & 0xFF)
37 #endif
38 #endif /* HAVE_UNSIGNED_CHAR */
39
40
41 #define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
42
43
44 /* Private version of data source object */
45
46 typedef struct _tga_source_struct * tga_source_ptr;
47
48 typedef struct _tga_source_struct {
49 struct cjpeg_source_struct pub; /* public fields */
50
51 j_compress_ptr cinfo; /* back link saves passing separate parm */
52
53 JSAMPARRAY colormap; /* Targa colormap (converted to my format) */
54
55 jvirt_sarray_ptr whole_image; /* Needed if funny input row order */
56 JDIMENSION current_row; /* Current logical row number to read */
57
58 /* Pointer to routine to extract next Targa pixel from input file */
59 JMETHOD(void, read_pixel, (tga_source_ptr sinfo));
60
61 /* Result of read_pixel is delivered here: */
62 U_CHAR tga_pixel[4];
63
64 int pixel_size; /* Bytes per Targa pixel (1 to 4) */
65 int cmap_length; /* colormap length */
66
67 /* State info for reading RLE-coded pixels; both counts must be init to 0 */
68 int block_count; /* # of pixels remaining in RLE block */
69 int dup_pixel_count; /* # of times to duplicate previous pixel */
70
71 /* This saves the correct pixel-row-expansion method for preload_image */
72 JMETHOD(JDIMENSION, get_pixel_rows, (j_compress_ptr cinfo,
73 cjpeg_source_ptr sinfo));
74 } tga_source_struct;
75
76
77 /* For expanding 5-bit pixel values to 8-bit with best rounding */
78
79 static const UINT8 c5to8bits[32] = {
80 0, 8, 16, 25, 33, 41, 49, 58,
81 66, 74, 82, 90, 99, 107, 115, 123,
82 132, 140, 148, 156, 165, 173, 181, 189,
83 197, 206, 214, 222, 230, 239, 247, 255
84 };
85
86
87
88 LOCAL(int)
89 read_byte (tga_source_ptr sinfo)
90 /* Read next byte from Targa file */
91 {
92 register FILE *infile = sinfo->pub.input_file;
93 register int c;
94
95 if ((c = getc(infile)) == EOF)
96 ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
97 return c;
98 }
99
100
101 LOCAL(void)
102 read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize)
103 /* Read the colormap from a Targa file */
104 {
105 int i;
106
107 /* Presently only handles 24-bit BGR format */
108 if (mapentrysize != 24)
109 ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
110
111 for (i = 0; i < cmaplen; i++) {
112 sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
113 sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
114 sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
115 }
116 }
117
118
119 /*
120 * read_pixel methods: get a single pixel from Targa file into tga_pixel[]
121 */
122
123 METHODDEF(void)
124 read_non_rle_pixel (tga_source_ptr sinfo)
125 /* Read one Targa pixel from the input file; no RLE expansion */
126 {
127 register int i;
128
129 for (i = 0; i < sinfo->pixel_size; i++) {
130 sinfo->tga_pixel[i] = (U_CHAR) read_byte(sinfo);
131 }
132 }
133
134 METHODDEF(void)
135 read_rle_pixel (tga_source_ptr sinfo)
136 /* Read one Targa pixel from the input file, expanding RLE data as needed */
137 {
138 register int i;
139
140 /* Duplicate previously read pixel? */
141 if (sinfo->dup_pixel_count > 0) {
142 sinfo->dup_pixel_count--;
143 return;
144 }
145
146 /* Time to read RLE block header? */
147 if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
148 i = read_byte(sinfo);
149 if (i & 0x80) { /* Start of duplicate-pixel block? */
150 sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
151 sinfo->block_count = 0; /* then read new block header */
152 } else {
153 sinfo->block_count = i & 0x7F; /* number of pixels after this one */
154 }
155 }
156
157 /* Read next pixel */
158 for (i = 0; i < sinfo->pixel_size; i++) {
159 sinfo->tga_pixel[i] = (U_CHAR) read_byte(sinfo);
160 }
161 }
162
163
164 /*
165 * Read one row of pixels.
166 *
167 * We provide several different versions depending on input file format.
168 */
169
170 METHODDEF(JDIMENSION)
171 get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
172 /* This version is for reading 8-bit grayscale pixels */
173 {
174 tga_source_ptr source = (tga_source_ptr) sinfo;
175 register JSAMPROW ptr;
176 register JDIMENSION col;
177
178 ptr = source->pub.buffer[0];
179 for (col = cinfo->image_width; col > 0; col--) {
180 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
181 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
182 }
183 return 1;
184 }
185
186 METHODDEF(JDIMENSION)
187 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
188 /* This version is for reading 8-bit colormap indexes */
189 {
190 tga_source_ptr source = (tga_source_ptr) sinfo;
191 register JSAMPROW ptr;
192 register JSAMPARRAY colormap;
193 register JDIMENSION col;
194 register int t;
195 int cmaplen;
196
197 ptr = source->pub.buffer[0];
198 colormap = source->colormap;
199 cmaplen = source->cmap_length;
200 for (col = cinfo->image_width; col > 0; col--) {
201 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
202 t = UCH(source->tga_pixel[0]);
203 if (t >= cmaplen)
204 ERREXIT(cinfo, JERR_TGA_BADPARMS);
205 *ptr++ = colormap[0][t];
206 *ptr++ = colormap[1][t];
207 *ptr++ = colormap[2][t];
208 }
209 return 1;
210 }
211
212 METHODDEF(JDIMENSION)
213 get_16bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
214 /* This version is for reading 16-bit pixels */
215 {
216 tga_source_ptr source = (tga_source_ptr) sinfo;
217 register int t;
218 register JSAMPROW ptr;
219 register JDIMENSION col;
220
221 ptr = source->pub.buffer[0];
222 for (col = cinfo->image_width; col > 0; col--) {
223 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
224 t = UCH(source->tga_pixel[0]);
225 t += UCH(source->tga_pixel[1]) << 8;
226 /* We expand 5 bit data to 8 bit sample width.
227 * The format of the 16-bit (LSB first) input word is
228 * xRRRRRGGGGGBBBBB
229 */
230 ptr[2] = (JSAMPLE) c5to8bits[t & 0x1F];
231 t >>= 5;
232 ptr[1] = (JSAMPLE) c5to8bits[t & 0x1F];
233 t >>= 5;
234 ptr[0] = (JSAMPLE) c5to8bits[t & 0x1F];
235 ptr += 3;
236 }
237 return 1;
238 }
239
240 METHODDEF(JDIMENSION)
241 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
242 /* This version is for reading 24-bit pixels */
243 {
244 tga_source_ptr source = (tga_source_ptr) sinfo;
245 register JSAMPROW ptr;
246 register JDIMENSION col;
247
248 ptr = source->pub.buffer[0];
249 for (col = cinfo->image_width; col > 0; col--) {
250 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
251 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[2]); /* change BGR to RGB order */
252 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[1]);
253 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
254 }
255 return 1;
256 }
257
258 /*
259 * Targa also defines a 32-bit pixel format with order B,G,R,A.
260 * We presently ignore the attribute byte, so the code for reading
261 * these pixels is identical to the 24-bit routine above.
262 * This works because the actual pixel length is only known to read_pixel.
263 */
264
265 #define get_32bit_row get_24bit_row
266
267
268 /*
269 * This method is for re-reading the input data in standard top-down
270 * row order. The entire image has already been read into whole_image
271 * with proper conversion of pixel format, but it's in a funny row order.
272 */
273
274 METHODDEF(JDIMENSION)
275 get_memory_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
276 {
277 tga_source_ptr source = (tga_source_ptr) sinfo;
278 JDIMENSION source_row;
279
280 /* Compute row of source that maps to current_row of normal order */
281 /* For now, assume image is bottom-up and not interlaced. */
282 /* NEEDS WORK to support interlaced images! */
283 source_row = cinfo->image_height - source->current_row - 1;
284
285 /* Fetch that row from virtual array */
286 source->pub.buffer = (*cinfo->mem->access_virt_sarray) ((j_common_ptr) cinfo,
287 source->whole_image, source_row, (JDIMENSION) 1, FALSE);
288
289 source->current_row++;
290 return 1;
291 }
292
293
294 /*
295 * This method loads the image into whole_image during the first call on
296 * get_pixel_rows. The get_pixel_rows pointer is then adjusted to call
297 * get_memory_row on subsequent calls.
298 */
299
300 METHODDEF(JDIMENSION)
301 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
302 {
303 tga_source_ptr source = (tga_source_ptr) sinfo;
304 JDIMENSION row;
305 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
306
307 /* Read the data into a virtual array in input-file row order. */
308 for (row = 0; row < cinfo->image_height; row++) {
309 if (progress != NULL) {
310 progress->pub.pass_counter = (long) row;
311 progress->pub.pass_limit = (long) cinfo->image_height;
312 (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
313 }
314 source->pub.buffer = (*cinfo->mem->access_virt_sarray)
315 ((j_common_ptr) cinfo, source->whole_image, row, (JDIMENSION) 1, TRUE);
316 (*source->get_pixel_rows) (cinfo, sinfo);
317 }
318 if (progress != NULL)
319 progress->completed_extra_passes++;
320
321 /* Set up to read from the virtual array in unscrambled order */
322 source->pub.get_pixel_rows = get_memory_row;
323 source->current_row = 0;
324 /* And read the first row */
325 return get_memory_row(cinfo, sinfo);
326 }
327
328
329 /*
330 * Read the file header; return image size and component count.
331 */
332
333 METHODDEF(void)
334 start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
335 {
336 tga_source_ptr source = (tga_source_ptr) sinfo;
337 U_CHAR targaheader[18];
338 int idlen, cmaptype, subtype, flags, interlace_type, components;
339 unsigned int width, height, maplen;
340 boolean is_bottom_up;
341
342 #define GET_2B(offset) ((unsigned int) UCH(targaheader[offset]) + \
343 (((unsigned int) UCH(targaheader[offset+1])) << 8))
344
345 if (! ReadOK(source->pub.input_file, targaheader, 18))
346 ERREXIT(cinfo, JERR_INPUT_EOF);
347
348 /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
349 if (targaheader[16] == 15)
350 targaheader[16] = 16;
351
352 idlen = UCH(targaheader[0]);
353 cmaptype = UCH(targaheader[1]);
354 subtype = UCH(targaheader[2]);
355 maplen = GET_2B(5);
356 width = GET_2B(12);
357 height = GET_2B(14);
358 source->pixel_size = UCH(targaheader[16]) >> 3;
359 flags = UCH(targaheader[17]); /* Image Descriptor byte */
360
361 is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
362 interlace_type = flags >> 6; /* bits 6/7 are interlace code */
363
364 if (cmaptype > 1 || /* cmaptype must be 0 or 1 */
365 width <= 0 || height <= 0 ||
366 source->pixel_size < 1 || source->pixel_size > 4 ||
367 (UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
368 interlace_type != 0) /* currently don't allow interlaced image */
369 ERREXIT(cinfo, JERR_TGA_BADPARMS);
370
371 if (subtype > 8) {
372 /* It's an RLE-coded file */
373 source->read_pixel = read_rle_pixel;
374 source->block_count = source->dup_pixel_count = 0;
375 subtype -= 8;
376 } else {
377 /* Non-RLE file */
378 source->read_pixel = read_non_rle_pixel;
379 }
380
381 /* Now should have subtype 1, 2, or 3 */
382 components = 3; /* until proven different */
383 cinfo->in_color_space = JCS_RGB;
384
385 switch (subtype) {
386 case 1: /* Colormapped image */
387 if (source->pixel_size == 1 && cmaptype == 1)
388 source->get_pixel_rows = get_8bit_row;
389 else
390 ERREXIT(cinfo, JERR_TGA_BADPARMS);
391 TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
392 break;
393 case 2: /* RGB image */
394 switch (source->pixel_size) {
395 case 2:
396 source->get_pixel_rows = get_16bit_row;
397 break;
398 case 3:
399 source->get_pixel_rows = get_24bit_row;
400 break;
401 case 4:
402 source->get_pixel_rows = get_32bit_row;
403 break;
404 default:
405 ERREXIT(cinfo, JERR_TGA_BADPARMS);
406 }
407 TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
408 break;
409 case 3: /* Grayscale image */
410 components = 1;
411 cinfo->in_color_space = JCS_GRAYSCALE;
412 if (source->pixel_size == 1)
413 source->get_pixel_rows = get_8bit_gray_row;
414 else
415 ERREXIT(cinfo, JERR_TGA_BADPARMS);
416 TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
417 break;
418 default:
419 ERREXIT(cinfo, JERR_TGA_BADPARMS);
420 }
421
422 if (is_bottom_up) {
423 /* Create a virtual array to buffer the upside-down image. */
424 source->whole_image = (*cinfo->mem->request_virt_sarray)
425 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
426 (JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1);
427 if (cinfo->progress != NULL) {
428 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
429 progress->total_extra_passes++; /* count file input as separate pass */
430 }
431 /* source->pub.buffer will point to the virtual array. */
432 source->pub.buffer_height = 1; /* in case anyone looks at it */
433 source->pub.get_pixel_rows = preload_image;
434 } else {
435 /* Don't need a virtual array, but do need a one-row input buffer. */
436 source->whole_image = NULL;
437 source->pub.buffer = (*cinfo->mem->alloc_sarray) ((j_common_ptr) cinfo,
438 JPOOL_IMAGE, (JDIMENSION) width * components, (JDIMENSION) 1);
439 source->pub.buffer_height = 1;
440 source->pub.get_pixel_rows = source->get_pixel_rows;
441 }
442
443 while (idlen--) /* Throw away ID field */
444 (void) read_byte(source);
445
446 if (maplen > 0) {
447 if (maplen > 256 || GET_2B(3) != 0)
448 ERREXIT(cinfo, JERR_TGA_BADCMAP);
449 /* Allocate space to store the colormap */
450 source->colormap = (*cinfo->mem->alloc_sarray) ((j_common_ptr) cinfo,
451 JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3);
452 source->cmap_length = (int) maplen;
453 /* and read it from the file */
454 read_colormap(source, (int) maplen, UCH(targaheader[7]));
455 } else {
456 if (cmaptype) /* but you promised a cmap! */
457 ERREXIT(cinfo, JERR_TGA_BADPARMS);
458 source->colormap = NULL;
459 source->cmap_length = 0;
460 }
461
462 cinfo->input_components = components;
463 cinfo->data_precision = 8;
464 cinfo->image_width = width;
465 cinfo->image_height = height;
466 }
467
468
469 /*
470 * Finish up at the end of the file.
471 */
472
473 METHODDEF(void)
474 finish_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
475 {
476 /* no work */
477 }
478
479
480 /*
481 * The module selection routine for Targa format input.
482 */
483
484 GLOBAL(cjpeg_source_ptr)
485 jinit_read_targa (j_compress_ptr cinfo)
486 {
487 tga_source_ptr source;
488
489 /* Create module interface object */
490 source = (tga_source_ptr) (*cinfo->mem->alloc_small)
491 ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(tga_source_struct));
492 source->cinfo = cinfo; /* make back link for subroutines */
493 /* Fill in method ptrs, except get_pixel_rows which start_input sets */
494 source->pub.start_input = start_input_tga;
495 source->pub.finish_input = finish_input_tga;
496
497 return &source->pub;
498 }
499
500 #endif /* TARGA_SUPPORTED */