1 /*
2 * rdtarga.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1996, Thomas G. Lane.
6 * It was modified by The libjpeg-turbo Project to include only code relevant
7 * to libjpeg-turbo.
8 * For conditions of distribution and use, see the accompanying README.ijg
9 * file.
10 *
11 * This file contains routines to read input images in Targa format.
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 Targa format).
19 *
20 * Based on code contributed by Lee Daniel Crocker.
21 */
22
23 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
24
25 #ifdef TARGA_SUPPORTED
26
27
28 /* Macros to deal with unsigned chars as efficiently as compiler allows */
29
30 #ifdef HAVE_UNSIGNED_CHAR
31 typedef unsigned char U_CHAR;
32 #define UCH(x) ((int) (x))
33 #else /* !HAVE_UNSIGNED_CHAR */
34 #ifdef __CHAR_UNSIGNED__
35 typedef char U_CHAR;
36 #define UCH(x) ((int) (x))
37 #else
38 typedef char U_CHAR;
39 #define UCH(x) ((int) (x) & 0xFF)
40 #endif
41 #endif /* HAVE_UNSIGNED_CHAR */
42
43
44 #define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
45
46
47 /* Private version of data source object */
48
49 typedef struct _tga_source_struct *tga_source_ptr;
50
51 typedef struct _tga_source_struct {
52 struct cjpeg_source_struct pub; /* public fields */
53
54 j_compress_ptr cinfo; /* back link saves passing separate parm */
55
56 JSAMPARRAY colormap; /* Targa colormap (converted to my format) */
57
58 jvirt_sarray_ptr whole_image; /* Needed if funny input row order */
59 JDIMENSION current_row; /* Current logical row number to read */
60
61 /* Pointer to routine to extract next Targa pixel from input file */
62 void (*read_pixel) (tga_source_ptr sinfo);
63
64 /* Result of read_pixel is delivered here: */
65 U_CHAR tga_pixel[4];
66
67 int pixel_size; /* Bytes per Targa pixel (1 to 4) */
68
69 /* State info for reading RLE-coded pixels; both counts must be init to 0 */
70 int block_count; /* # of pixels remaining in RLE block */
71 int dup_pixel_count; /* # of times to duplicate previous pixel */
72
73 /* This saves the correct pixel-row-expansion method for preload_image */
74 JDIMENSION (*get_pixel_rows) (j_compress_ptr cinfo, cjpeg_source_ptr sinfo);
75 } tga_source_struct;
76
77
78 /* For expanding 5-bit pixel values to 8-bit with best rounding */
79
80 static const UINT8 c5to8bits[32] = {
81 0, 8, 16, 25, 33, 41, 49, 58,
82 66, 74, 82, 90, 99, 107, 115, 123,
83 132, 140, 148, 156, 165, 173, 181, 189,
84 197, 206, 214, 222, 230, 239, 247, 255
85 };
86
87
88
89 LOCAL(int)
read_byte(tga_source_ptr sinfo)90 read_byte (tga_source_ptr sinfo)
91 /* Read next byte from Targa file */
92 {
93 register FILE *infile = sinfo->pub.input_file;
94 register int c;
95
96 if ((c = getc(infile)) == EOF)
97 ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
98 return c;
99 }
100
101
102 LOCAL(void)
read_colormap(tga_source_ptr sinfo,int cmaplen,int mapentrysize)103 read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize)
104 /* Read the colormap from a Targa file */
105 {
106 int i;
107
108 /* Presently only handles 24-bit BGR format */
109 if (mapentrysize != 24)
110 ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
111
112 for (i = 0; i < cmaplen; i++) {
113 sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
114 sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
115 sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
116 }
117 }
118
119
120 /*
121 * read_pixel methods: get a single pixel from Targa file into tga_pixel[]
122 */
123
124 METHODDEF(void)
read_non_rle_pixel(tga_source_ptr sinfo)125 read_non_rle_pixel (tga_source_ptr sinfo)
126 /* Read one Targa pixel from the input file; no RLE expansion */
127 {
128 register FILE *infile = sinfo->pub.input_file;
129 register int i;
130
131 for (i = 0; i < sinfo->pixel_size; i++) {
132 sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
133 }
134 }
135
136
137 METHODDEF(void)
read_rle_pixel(tga_source_ptr sinfo)138 read_rle_pixel (tga_source_ptr sinfo)
139 /* Read one Targa pixel from the input file, expanding RLE data as needed */
140 {
141 register FILE *infile = sinfo->pub.input_file;
142 register int i;
143
144 /* Duplicate previously read pixel? */
145 if (sinfo->dup_pixel_count > 0) {
146 sinfo->dup_pixel_count--;
147 return;
148 }
149
150 /* Time to read RLE block header? */
151 if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
152 i = read_byte(sinfo);
153 if (i & 0x80) { /* Start of duplicate-pixel block? */
154 sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
155 sinfo->block_count = 0; /* then read new block header */
156 } else {
157 sinfo->block_count = i & 0x7F; /* number of pixels after this one */
158 }
159 }
160
161 /* Read next pixel */
162 for (i = 0; i < sinfo->pixel_size; i++) {
163 sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
164 }
165 }
166
167
168 /*
169 * Read one row of pixels.
170 *
171 * We provide several different versions depending on input file format.
172 */
173
174
175 METHODDEF(JDIMENSION)
get_8bit_gray_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)176 get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
177 /* This version is for reading 8-bit grayscale pixels */
178 {
179 tga_source_ptr source = (tga_source_ptr) sinfo;
180 register JSAMPROW ptr;
181 register JDIMENSION col;
182
183 ptr = source->pub.buffer[0];
184 for (col = cinfo->image_width; col > 0; col--) {
185 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
186 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
187 }
188 return 1;
189 }
190
191 METHODDEF(JDIMENSION)
get_8bit_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)192 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
193 /* This version is for reading 8-bit colormap indexes */
194 {
195 tga_source_ptr source = (tga_source_ptr) sinfo;
196 register int t;
197 register JSAMPROW ptr;
198 register JDIMENSION col;
199 register JSAMPARRAY colormap = source->colormap;
200
201 ptr = source->pub.buffer[0];
202 for (col = cinfo->image_width; col > 0; col--) {
203 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
204 t = UCH(source->tga_pixel[0]);
205 *ptr++ = colormap[0][t];
206 *ptr++ = colormap[1][t];
207 *ptr++ = colormap[2][t];
208 }
209 return 1;
210 }
211
212 METHODDEF(JDIMENSION)
get_16bit_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)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)
get_24bit_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)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)
get_memory_row(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)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)
287 ((j_common_ptr) cinfo, source->whole_image,
288 source_row, (JDIMENSION) 1, FALSE);
289
290 source->current_row++;
291 return 1;
292 }
293
294
295 /*
296 * This method loads the image into whole_image during the first call on
297 * get_pixel_rows. The get_pixel_rows pointer is then adjusted to call
298 * get_memory_row on subsequent calls.
299 */
300
301 METHODDEF(JDIMENSION)
preload_image(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)302 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
303 {
304 tga_source_ptr source = (tga_source_ptr) sinfo;
305 JDIMENSION row;
306 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
307
308 /* Read the data into a virtual array in input-file row order. */
309 for (row = 0; row < cinfo->image_height; row++) {
310 if (progress != NULL) {
311 progress->pub.pass_counter = (long) row;
312 progress->pub.pass_limit = (long) cinfo->image_height;
313 (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
314 }
315 source->pub.buffer = (*cinfo->mem->access_virt_sarray)
316 ((j_common_ptr) cinfo, source->whole_image, row, (JDIMENSION) 1, TRUE);
317 (*source->get_pixel_rows) (cinfo, sinfo);
318 }
319 if (progress != NULL)
320 progress->completed_extra_passes++;
321
322 /* Set up to read from the virtual array in unscrambled order */
323 source->pub.get_pixel_rows = get_memory_row;
324 source->current_row = 0;
325 /* And read the first row */
326 return get_memory_row(cinfo, sinfo);
327 }
328
329
330 /*
331 * Read the file header; return image size and component count.
332 */
333
334 METHODDEF(void)
start_input_tga(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)335 start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
336 {
337 tga_source_ptr source = (tga_source_ptr) sinfo;
338 U_CHAR targaheader[18];
339 int idlen, cmaptype, subtype, flags, interlace_type, components;
340 unsigned int width, height, maplen;
341 boolean is_bottom_up;
342
343 #define GET_2B(offset) ((unsigned int) UCH(targaheader[offset]) + \
344 (((unsigned int) UCH(targaheader[offset+1])) << 8))
345
346 if (! ReadOK(source->pub.input_file, targaheader, 18))
347 ERREXIT(cinfo, JERR_INPUT_EOF);
348
349 /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
350 if (targaheader[16] == 15)
351 targaheader[16] = 16;
352
353 idlen = UCH(targaheader[0]);
354 cmaptype = UCH(targaheader[1]);
355 subtype = UCH(targaheader[2]);
356 maplen = GET_2B(5);
357 width = GET_2B(12);
358 height = GET_2B(14);
359 source->pixel_size = UCH(targaheader[16]) >> 3;
360 flags = UCH(targaheader[17]); /* Image Descriptor byte */
361
362 is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
363 interlace_type = flags >> 6; /* bits 6/7 are interlace code */
364
365 if (cmaptype > 1 || /* cmaptype must be 0 or 1 */
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 width == 0 || height == 0) /* image width/height must be non-zero */
370 ERREXIT(cinfo, JERR_TGA_BADPARMS);
371
372 if (subtype > 8) {
373 /* It's an RLE-coded file */
374 source->read_pixel = read_rle_pixel;
375 source->block_count = source->dup_pixel_count = 0;
376 subtype -= 8;
377 } else {
378 /* Non-RLE file */
379 source->read_pixel = read_non_rle_pixel;
380 }
381
382 /* Now should have subtype 1, 2, or 3 */
383 components = 3; /* until proven different */
384 cinfo->in_color_space = JCS_RGB;
385
386 switch (subtype) {
387 case 1: /* Colormapped image */
388 if (source->pixel_size == 1 && cmaptype == 1)
389 source->get_pixel_rows = get_8bit_row;
390 else
391 ERREXIT(cinfo, JERR_TGA_BADPARMS);
392 TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
393 break;
394 case 2: /* RGB image */
395 switch (source->pixel_size) {
396 case 2:
397 source->get_pixel_rows = get_16bit_row;
398 break;
399 case 3:
400 source->get_pixel_rows = get_24bit_row;
401 break;
402 case 4:
403 source->get_pixel_rows = get_32bit_row;
404 break;
405 default:
406 ERREXIT(cinfo, JERR_TGA_BADPARMS);
407 break;
408 }
409 TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
410 break;
411 case 3: /* Grayscale image */
412 components = 1;
413 cinfo->in_color_space = JCS_GRAYSCALE;
414 if (source->pixel_size == 1)
415 source->get_pixel_rows = get_8bit_gray_row;
416 else
417 ERREXIT(cinfo, JERR_TGA_BADPARMS);
418 TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
419 break;
420 default:
421 ERREXIT(cinfo, JERR_TGA_BADPARMS);
422 break;
423 }
424
425 if (is_bottom_up) {
426 /* Create a virtual array to buffer the upside-down image. */
427 source->whole_image = (*cinfo->mem->request_virt_sarray)
428 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
429 (JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1);
430 if (cinfo->progress != NULL) {
431 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
432 progress->total_extra_passes++; /* count file input as separate pass */
433 }
434 /* source->pub.buffer will point to the virtual array. */
435 source->pub.buffer_height = 1; /* in case anyone looks at it */
436 source->pub.get_pixel_rows = preload_image;
437 } else {
438 /* Don't need a virtual array, but do need a one-row input buffer. */
439 source->whole_image = NULL;
440 source->pub.buffer = (*cinfo->mem->alloc_sarray)
441 ((j_common_ptr) cinfo, JPOOL_IMAGE,
442 (JDIMENSION) width * components, (JDIMENSION) 1);
443 source->pub.buffer_height = 1;
444 source->pub.get_pixel_rows = source->get_pixel_rows;
445 }
446
447 while (idlen--) /* Throw away ID field */
448 (void) read_byte(source);
449
450 if (maplen > 0) {
451 if (maplen > 256 || GET_2B(3) != 0)
452 ERREXIT(cinfo, JERR_TGA_BADCMAP);
453 /* Allocate space to store the colormap */
454 source->colormap = (*cinfo->mem->alloc_sarray)
455 ((j_common_ptr) cinfo, JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3);
456 /* and read it from the file */
457 read_colormap(source, (int) maplen, UCH(targaheader[7]));
458 } else {
459 if (cmaptype) /* but you promised a cmap! */
460 ERREXIT(cinfo, JERR_TGA_BADPARMS);
461 source->colormap = NULL;
462 }
463
464 cinfo->input_components = components;
465 cinfo->data_precision = 8;
466 cinfo->image_width = width;
467 cinfo->image_height = height;
468 }
469
470
471 /*
472 * Finish up at the end of the file.
473 */
474
475 METHODDEF(void)
finish_input_tga(j_compress_ptr cinfo,cjpeg_source_ptr sinfo)476 finish_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
477 {
478 /* no work */
479 }
480
481
482 /*
483 * The module selection routine for Targa format input.
484 */
485
486 GLOBAL(cjpeg_source_ptr)
jinit_read_targa(j_compress_ptr cinfo)487 jinit_read_targa (j_compress_ptr cinfo)
488 {
489 tga_source_ptr source;
490
491 /* Create module interface object */
492 source = (tga_source_ptr)
493 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
494 sizeof(tga_source_struct));
495 source->cinfo = cinfo; /* make back link for subroutines */
496 /* Fill in method ptrs, except get_pixel_rows which start_input sets */
497 source->pub.start_input = start_input_tga;
498 source->pub.finish_input = finish_input_tga;
499
500 return (cjpeg_source_ptr) source;
501 }
502
503 #endif /* TARGA_SUPPORTED */
504