1 /*
2 * rdtarga.c
3 *
4 * Copyright (C) 1991-1994, 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 Targa format.
9 *
10 * These routines may need modification for non-Unix environments or
11 * specialized applications. As they stand, they assume input from
12 * an ordinary stdio stream. They further assume that reading begins
13 * at the start of the file; start_input may need work if the
14 * user interface has already read some data (e.g., to determine that
15 * the file is indeed Targa format).
16 *
17 * Based on code contributed by Lee Daniel Crocker.
18 */
19
20 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
21
22 #ifdef TARGA_SUPPORTED
23
24
25 /* Macros to deal with unsigned chars as efficiently as compiler allows */
26
27 #ifdef HAVE_UNSIGNED_CHAR
28 typedef unsigned char U_CHAR;
29 #define UCH(x) ((int) (x))
30 #else /* !HAVE_UNSIGNED_CHAR */
31 #ifdef CHAR_IS_UNSIGNED
32 typedef char U_CHAR;
33 #define UCH(x) ((int) (x))
34 #else
35 typedef char U_CHAR;
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
66 /* State info for reading RLE-coded pixels; both counts must be init to 0 */
67 int block_count; /* # of pixels remaining in RLE block */
68 int dup_pixel_count; /* # of times to duplicate previous pixel */
69
70 /* This saves the correct pixel-row-expansion method for preload_image */
71 JMETHOD(JDIMENSION, get_pixel_rows, (j_compress_ptr cinfo,
72 cjpeg_source_ptr sinfo));
73 } tga_source_struct;
74
75
76 /* For expanding 5-bit pixel values to 8-bit with best rounding */
77
78 static const UINT8 c5to8bits[32] = {
79 0, 8, 16, 24, 32, 41, 49, 57,
80 65, 74, 82, 90, 98, 106, 115, 123,
81 131, 139, 148, 156, 164, 172, 180, 189,
82 197, 205, 213, 222, 230, 238, 246, 255
83 };
84
85
86
87 LOCAL int
read_byte(tga_source_ptr sinfo)88 read_byte (tga_source_ptr sinfo)
89 /* Read next byte from Targa file */
90 {
91 register FILE *infile = sinfo->pub.input_file;
92 register int c;
93
94 if ((c = getc(infile)) == EOF)
95 ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
96 return c;
97 }
98
99
100 LOCAL void
read_colormap(tga_source_ptr sinfo,int cmaplen,int mapentrysize)101 read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize)
102 /* Read the colormap from a Targa file */
103 {
104 int i;
105
106 /* Presently only handles 24-bit BGR format */
107 if (mapentrysize != 24)
108 ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
109
110 for (i = 0; i < cmaplen; i++) {
111 sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
112 sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
113 sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
114 }
115 }
116
117
118 /*
119 * read_pixel methods: get a single pixel from Targa file into tga_pixel[]
120 */
121
122 LOCAL void
read_non_rle_pixel(tga_source_ptr sinfo)123 read_non_rle_pixel (tga_source_ptr sinfo)
124 /* Read one Targa pixel from the input file; no RLE expansion */
125 {
126 register FILE *infile = sinfo->pub.input_file;
127 register int i;
128
129 for (i = 0; i < sinfo->pixel_size; i++) {
130 sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
131 }
132 }
133
134
135 LOCAL void
read_rle_pixel(tga_source_ptr sinfo)136 read_rle_pixel (tga_source_ptr sinfo)
137 /* Read one Targa pixel from the input file, expanding RLE data as needed */
138 {
139 register FILE *infile = sinfo->pub.input_file;
140 register int i;
141
142 /* Duplicate previously read pixel? */
143 if (sinfo->dup_pixel_count > 0) {
144 sinfo->dup_pixel_count--;
145 return;
146 }
147
148 /* Time to read RLE block header? */
149 if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
150 i = read_byte(sinfo);
151 if (i & 0x80) { /* Start of duplicate-pixel block? */
152 sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
153 sinfo->block_count = 0; /* then read new block header */
154 } else {
155 sinfo->block_count = i & 0x7F; /* number of pixels after this one */
156 }
157 }
158
159 /* Read next pixel */
160 for (i = 0; i < sinfo->pixel_size; i++) {
161 sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
162 }
163 }
164
165
166 /*
167 * Read one row of pixels.
168 *
169 * We provide several different versions depending on input file format.
170 */
171
172
173 METHODDEF JDIMENSION
get_8bit_gray_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)174 get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
175 /* This version is for reading 8-bit grayscale pixels */
176 {
177 tga_source_ptr source = (tga_source_ptr) sinfo;
178 register JSAMPROW ptr;
179 register JDIMENSION col;
180
181 ptr = source->pub.buffer[0];
182 for (col = cinfo->image_width; col > 0; col--) {
183 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
184 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
185 }
186 return 1;
187 }
188
189 METHODDEF JDIMENSION
get_8bit_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)190 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
191 /* This version is for reading 8-bit colormap indexes */
192 {
193 tga_source_ptr source = (tga_source_ptr) sinfo;
194 register int t;
195 register JSAMPROW ptr;
196 register JDIMENSION col;
197 register JSAMPARRAY colormap = source->colormap;
198
199 ptr = source->pub.buffer[0];
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 *ptr++ = colormap[0][t];
204 *ptr++ = colormap[1][t];
205 *ptr++ = colormap[2][t];
206 }
207 return 1;
208 }
209
210 METHODDEF JDIMENSION
get_16bit_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)211 get_16bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
212 /* This version is for reading 16-bit pixels */
213 {
214 tga_source_ptr source = (tga_source_ptr) sinfo;
215 register int t;
216 register JSAMPROW ptr;
217 register JDIMENSION col;
218
219 ptr = source->pub.buffer[0];
220 for (col = cinfo->image_width; col > 0; col--) {
221 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
222 t = UCH(source->tga_pixel[0]);
223 t += UCH(source->tga_pixel[1]) << 8;
224 /* We expand 5 bit data to 8 bit sample width.
225 * The format of the 16-bit (LSB first) input word is
226 * xRRRRRGGGGGBBBBB
227 */
228 ptr[2] = (JSAMPLE) c5to8bits[t & 0x1F];
229 t >>= 5;
230 ptr[1] = (JSAMPLE) c5to8bits[t & 0x1F];
231 t >>= 5;
232 ptr[0] = (JSAMPLE) c5to8bits[t & 0x1F];
233 ptr += 3;
234 }
235 return 1;
236 }
237
238 METHODDEF JDIMENSION
get_24bit_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)239 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
240 /* This version is for reading 24-bit pixels */
241 {
242 tga_source_ptr source = (tga_source_ptr) sinfo;
243 register JSAMPROW ptr;
244 register JDIMENSION col;
245
246 ptr = source->pub.buffer[0];
247 for (col = cinfo->image_width; col > 0; col--) {
248 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
249 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[2]); /* change BGR to RGB order */
250 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[1]);
251 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
252 }
253 return 1;
254 }
255
256 /*
257 * Targa also defines a 32-bit pixel format with order B,G,R,A.
258 * We presently ignore the attribute byte, so the code for reading
259 * these pixels is identical to the 24-bit routine above.
260 * This works because the actual pixel length is only known to read_pixel.
261 */
262
263 #define get_32bit_row get_24bit_row
264
265
266 /*
267 * This method is for re-reading the input data in standard top-down
268 * row order. The entire image has already been read into whole_image
269 * with proper conversion of pixel format, but it's in a funny row order.
270 */
271
272 METHODDEF JDIMENSION
get_memory_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)273 get_memory_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
274 {
275 tga_source_ptr source = (tga_source_ptr) sinfo;
276 JDIMENSION source_row;
277
278 /* Compute row of source that maps to current_row of normal order */
279 /* For now, assume image is bottom-up and not interlaced. */
280 /* NEEDS WORK to support interlaced images! */
281 source_row = cinfo->image_height - source->current_row - 1;
282
283 /* Fetch that row from virtual array */
284 source->pub.buffer = (*cinfo->mem->access_virt_sarray)
285 ((j_common_ptr) cinfo, source->whole_image, source_row, FALSE);
286
287 source->current_row++;
288 return 1;
289 }
290
291
292 /*
293 * This method loads the image into whole_image during the first call on
294 * get_pixel_rows. The get_pixel_rows pointer is then adjusted to call
295 * get_memory_row on subsequent calls.
296 */
297
298 METHODDEF JDIMENSION
preload_image(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)299 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
300 {
301 tga_source_ptr source = (tga_source_ptr) sinfo;
302 JDIMENSION row;
303 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
304
305 /* Read the data into a virtual array in input-file row order. */
306 for (row = 0; row < cinfo->image_height; row++) {
307 if (progress != NULL) {
308 progress->pub.pass_counter = (long) row;
309 progress->pub.pass_limit = (long) cinfo->image_height;
310 (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
311 }
312 source->pub.buffer = (*cinfo->mem->access_virt_sarray)
313 ((j_common_ptr) cinfo, source->whole_image, row, TRUE);
314 (*source->get_pixel_rows) (cinfo, sinfo);
315 }
316 if (progress != NULL)
317 progress->completed_extra_passes++;
318
319 /* Set up to read from the virtual array in unscrambled order */
320 source->pub.get_pixel_rows = get_memory_row;
321 source->current_row = 0;
322 /* And read the first row */
323 return get_memory_row(cinfo, sinfo);
324 }
325
326
327 /*
328 * Read the file header; return image size and component count.
329 */
330
331 METHODDEF void
start_input_tga(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)332 start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
333 {
334 tga_source_ptr source = (tga_source_ptr) sinfo;
335 U_CHAR targaheader[18];
336 int idlen, cmaptype, subtype, flags, interlace_type, components;
337 unsigned int width, height, maplen;
338 boolean is_bottom_up;
339
340 #define GET_2B(offset) ((unsigned int) UCH(targaheader[offset]) + \
341 (((unsigned int) UCH(targaheader[offset+1])) << 8))
342
343 if (! ReadOK(source->pub.input_file, targaheader, 18))
344 ERREXIT(cinfo, JERR_INPUT_EOF);
345
346 /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
347 if (targaheader[16] == 15)
348 targaheader[16] = 16;
349
350 idlen = UCH(targaheader[0]);
351 cmaptype = UCH(targaheader[1]);
352 subtype = UCH(targaheader[2]);
353 maplen = GET_2B(5);
354 width = GET_2B(12);
355 height = GET_2B(14);
356 source->pixel_size = UCH(targaheader[16]) >> 3;
357 flags = UCH(targaheader[17]); /* Image Descriptor byte */
358
359 is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
360 interlace_type = flags >> 6; /* bits 6/7 are interlace code */
361
362 if (cmaptype > 1 || /* cmaptype must be 0 or 1 */
363 source->pixel_size < 1 || source->pixel_size > 4 ||
364 (UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
365 interlace_type != 0) /* currently don't allow interlaced image */
366 ERREXIT(cinfo, JERR_TGA_BADPARMS);
367
368 if (subtype > 8) {
369 /* It's an RLE-coded file */
370 source->read_pixel = read_rle_pixel;
371 source->block_count = source->dup_pixel_count = 0;
372 subtype -= 8;
373 } else {
374 /* Non-RLE file */
375 source->read_pixel = read_non_rle_pixel;
376 }
377
378 /* Now should have subtype 1, 2, or 3 */
379 components = 3; /* until proven different */
380 cinfo->in_color_space = JCS_RGB;
381
382 switch (subtype) {
383 case 1: /* Colormapped image */
384 if (source->pixel_size == 1 && cmaptype == 1)
385 source->get_pixel_rows = get_8bit_row;
386 else
387 ERREXIT(cinfo, JERR_TGA_BADPARMS);
388 TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
389 break;
390 case 2: /* RGB image */
391 switch (source->pixel_size) {
392 case 2:
393 source->get_pixel_rows = get_16bit_row;
394 break;
395 case 3:
396 source->get_pixel_rows = get_24bit_row;
397 break;
398 case 4:
399 source->get_pixel_rows = get_32bit_row;
400 break;
401 default:
402 ERREXIT(cinfo, JERR_TGA_BADPARMS);
403 break;
404 }
405 TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
406 break;
407 case 3: /* Grayscale image */
408 components = 1;
409 cinfo->in_color_space = JCS_GRAYSCALE;
410 if (source->pixel_size == 1)
411 source->get_pixel_rows = get_8bit_gray_row;
412 else
413 ERREXIT(cinfo, JERR_TGA_BADPARMS);
414 TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
415 break;
416 default:
417 ERREXIT(cinfo, JERR_TGA_BADPARMS);
418 break;
419 }
420
421 if (is_bottom_up) {
422 /* Create a virtual array to buffer the upside-down image. */
423 source->whole_image = (*cinfo->mem->request_virt_sarray)
424 ((j_common_ptr) cinfo, JPOOL_IMAGE,
425 (JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1);
426 if (cinfo->progress != NULL) {
427 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
428 progress->total_extra_passes++; /* count file input as separate pass */
429 }
430 /* source->pub.buffer will point to the virtual array. */
431 source->pub.buffer_height = 1; /* in case anyone looks at it */
432 source->pub.get_pixel_rows = preload_image;
433 } else {
434 /* Don't need a virtual array, but do need a one-row input buffer. */
435 source->whole_image = NULL;
436 source->pub.buffer = (*cinfo->mem->alloc_sarray)
437 ((j_common_ptr) cinfo, JPOOL_IMAGE,
438 (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)
451 ((j_common_ptr) cinfo, JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3);
452 /* and read it from the file */
453 read_colormap(source, (int) maplen, UCH(targaheader[7]));
454 } else {
455 if (cmaptype) /* but you promised a cmap! */
456 ERREXIT(cinfo, JERR_TGA_BADPARMS);
457 source->colormap = NULL;
458 }
459
460 cinfo->input_components = components;
461 cinfo->data_precision = 8;
462 cinfo->image_width = width;
463 cinfo->image_height = height;
464 }
465
466
467 /*
468 * Finish up at the end of the file.
469 */
470
471 METHODDEF void
finish_input_tga(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)472 finish_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
473 {
474 /* no work */
475 }
476
477
478 /*
479 * The module selection routine for Targa format input.
480 */
481
482 GLOBAL cjpeg_source_ptr
jinit_read_targa(j_compress_ptr cinfo)483 jinit_read_targa (j_compress_ptr cinfo)
484 {
485 tga_source_ptr source;
486
487 /* Create module interface object */
488 source = (tga_source_ptr)
489 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
490 SIZEOF(tga_source_struct));
491 source->cinfo = cinfo; /* make back link for subroutines */
492 /* Fill in method ptrs, except get_pixel_rows which start_input sets */
493 source->pub.start_input = start_input_tga;
494 source->pub.finish_input = finish_input_tga;
495
496 return (cjpeg_source_ptr) source;
497 }
498
499 #endif /* TARGA_SUPPORTED */
500