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
8 * For conditions of distribution and use, see the accompanying README file.
10 * This file contains routines to read input images in Targa format.
12 * These routines may need modification for non-Unix environments or
13 * specialized applications. As they stand, they assume input from
14 * an ordinary stdio stream. They further assume that reading begins
15 * at the start of the file; start_input may need work if the
16 * user interface has already read some data (e.g., to determine that
17 * the file is indeed Targa format).
19 * Based on code contributed by Lee Daniel Crocker.
22 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
24 #ifdef TARGA_SUPPORTED
27 /* Macros to deal with unsigned chars as efficiently as compiler allows */
29 #ifdef HAVE_UNSIGNED_CHAR
30 typedef unsigned char U_CHAR;
31 #define UCH(x) ((int) (x))
32 #else /* !HAVE_UNSIGNED_CHAR */
33 #ifdef __CHAR_UNSIGNED__
35 #define UCH(x) ((int) (x))
38 #define UCH(x) ((int) (x) & 0xFF)
40 #endif /* HAVE_UNSIGNED_CHAR */
43 #define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
46 /* Private version of data source object */
48 typedef struct _tga_source_struct * tga_source_ptr;
50 typedef struct _tga_source_struct {
51 struct cjpeg_source_struct pub; /* public fields */
53 j_compress_ptr cinfo; /* back link saves passing separate parm */
55 JSAMPARRAY colormap; /* Targa colormap (converted to my format) */
57 jvirt_sarray_ptr whole_image; /* Needed if funny input row order */
58 JDIMENSION current_row; /* Current logical row number to read */
60 /* Pointer to routine to extract next Targa pixel from input file */
61 void (*read_pixel) (tga_source_ptr sinfo);
63 /* Result of read_pixel is delivered here: */
66 int pixel_size; /* Bytes per Targa pixel (1 to 4) */
68 /* State info for reading RLE-coded pixels; both counts must be init to 0 */
69 int block_count; /* # of pixels remaining in RLE block */
70 int dup_pixel_count; /* # of times to duplicate previous pixel */
72 /* This saves the correct pixel-row-expansion method for preload_image */
73 JDIMENSION (*get_pixel_rows) (j_compress_ptr cinfo, cjpeg_source_ptr sinfo);
77 /* For expanding 5-bit pixel values to 8-bit with best rounding */
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
89 read_byte (tga_source_ptr sinfo)
90 /* Read next byte from Targa file */
92 register FILE *infile = sinfo->pub.input_file;
95 if ((c = getc(infile)) == EOF)
96 ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
102 read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize)
103 /* Read the colormap from a Targa file */
107 /* Presently only handles 24-bit BGR format */
108 if (mapentrysize != 24)
109 ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
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);
120 * read_pixel methods: get a single pixel from Targa file into tga_pixel[]
124 read_non_rle_pixel (tga_source_ptr sinfo)
125 /* Read one Targa pixel from the input file; no RLE expansion */
127 register FILE *infile = sinfo->pub.input_file;
130 for (i = 0; i < sinfo->pixel_size; i++) {
131 sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
137 read_rle_pixel (tga_source_ptr sinfo)
138 /* Read one Targa pixel from the input file, expanding RLE data as needed */
140 register FILE *infile = sinfo->pub.input_file;
143 /* Duplicate previously read pixel? */
144 if (sinfo->dup_pixel_count > 0) {
145 sinfo->dup_pixel_count--;
149 /* Time to read RLE block header? */
150 if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
151 i = read_byte(sinfo);
152 if (i & 0x80) { /* Start of duplicate-pixel block? */
153 sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
154 sinfo->block_count = 0; /* then read new block header */
156 sinfo->block_count = i & 0x7F; /* number of pixels after this one */
160 /* Read next pixel */
161 for (i = 0; i < sinfo->pixel_size; i++) {
162 sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
168 * Read one row of pixels.
170 * We provide several different versions depending on input file format.
174 METHODDEF(JDIMENSION)
175 get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
176 /* This version is for reading 8-bit grayscale pixels */
178 tga_source_ptr source = (tga_source_ptr) sinfo;
179 register JSAMPROW ptr;
180 register JDIMENSION col;
182 ptr = source->pub.buffer[0];
183 for (col = cinfo->image_width; col > 0; col--) {
184 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
185 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
190 METHODDEF(JDIMENSION)
191 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
192 /* This version is for reading 8-bit colormap indexes */
194 tga_source_ptr source = (tga_source_ptr) sinfo;
196 register JSAMPROW ptr;
197 register JDIMENSION col;
198 register JSAMPARRAY colormap = source->colormap;
200 ptr = source->pub.buffer[0];
201 for (col = cinfo->image_width; col > 0; col--) {
202 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
203 t = UCH(source->tga_pixel[0]);
204 *ptr++ = colormap[0][t];
205 *ptr++ = colormap[1][t];
206 *ptr++ = colormap[2][t];
211 METHODDEF(JDIMENSION)
212 get_16bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
213 /* This version is for reading 16-bit pixels */
215 tga_source_ptr source = (tga_source_ptr) sinfo;
217 register JSAMPROW ptr;
218 register JDIMENSION col;
220 ptr = source->pub.buffer[0];
221 for (col = cinfo->image_width; col > 0; col--) {
222 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
223 t = UCH(source->tga_pixel[0]);
224 t += UCH(source->tga_pixel[1]) << 8;
225 /* We expand 5 bit data to 8 bit sample width.
226 * The format of the 16-bit (LSB first) input word is
229 ptr[2] = (JSAMPLE) c5to8bits[t & 0x1F];
231 ptr[1] = (JSAMPLE) c5to8bits[t & 0x1F];
233 ptr[0] = (JSAMPLE) c5to8bits[t & 0x1F];
239 METHODDEF(JDIMENSION)
240 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
241 /* This version is for reading 24-bit pixels */
243 tga_source_ptr source = (tga_source_ptr) sinfo;
244 register JSAMPROW ptr;
245 register JDIMENSION col;
247 ptr = source->pub.buffer[0];
248 for (col = cinfo->image_width; col > 0; col--) {
249 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
250 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[2]); /* change BGR to RGB order */
251 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[1]);
252 *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
258 * Targa also defines a 32-bit pixel format with order B,G,R,A.
259 * We presently ignore the attribute byte, so the code for reading
260 * these pixels is identical to the 24-bit routine above.
261 * This works because the actual pixel length is only known to read_pixel.
264 #define get_32bit_row get_24bit_row
268 * This method is for re-reading the input data in standard top-down
269 * row order. The entire image has already been read into whole_image
270 * with proper conversion of pixel format, but it's in a funny row order.
273 METHODDEF(JDIMENSION)
274 get_memory_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
276 tga_source_ptr source = (tga_source_ptr) sinfo;
277 JDIMENSION source_row;
279 /* Compute row of source that maps to current_row of normal order */
280 /* For now, assume image is bottom-up and not interlaced. */
281 /* NEEDS WORK to support interlaced images! */
282 source_row = cinfo->image_height - source->current_row - 1;
284 /* Fetch that row from virtual array */
285 source->pub.buffer = (*cinfo->mem->access_virt_sarray)
286 ((j_common_ptr) cinfo, source->whole_image,
287 source_row, (JDIMENSION) 1, FALSE);
289 source->current_row++;
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.
300 METHODDEF(JDIMENSION)
301 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
303 tga_source_ptr source = (tga_source_ptr) sinfo;
305 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
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);
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);
318 if (progress != NULL)
319 progress->completed_extra_passes++;
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);
330 * Read the file header; return image size and component count.
334 start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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;
342 #define GET_2B(offset) ((unsigned int) UCH(targaheader[offset]) + \
343 (((unsigned int) UCH(targaheader[offset+1])) << 8))
345 if (! ReadOK(source->pub.input_file, targaheader, 18))
346 ERREXIT(cinfo, JERR_INPUT_EOF);
348 /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
349 if (targaheader[16] == 15)
350 targaheader[16] = 16;
352 idlen = UCH(targaheader[0]);
353 cmaptype = UCH(targaheader[1]);
354 subtype = UCH(targaheader[2]);
358 source->pixel_size = UCH(targaheader[16]) >> 3;
359 flags = UCH(targaheader[17]); /* Image Descriptor byte */
361 is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
362 interlace_type = flags >> 6; /* bits 6/7 are interlace code */
364 if (cmaptype > 1 || /* cmaptype must be 0 or 1 */
365 source->pixel_size < 1 || source->pixel_size > 4 ||
366 (UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
367 interlace_type != 0 || /* currently don't allow interlaced image */
368 width == 0 || height == 0) /* image width/height must be non-zero */
369 ERREXIT(cinfo, JERR_TGA_BADPARMS);
372 /* It's an RLE-coded file */
373 source->read_pixel = read_rle_pixel;
374 source->block_count = source->dup_pixel_count = 0;
378 source->read_pixel = read_non_rle_pixel;
381 /* Now should have subtype 1, 2, or 3 */
382 components = 3; /* until proven different */
383 cinfo->in_color_space = JCS_RGB;
386 case 1: /* Colormapped image */
387 if (source->pixel_size == 1 && cmaptype == 1)
388 source->get_pixel_rows = get_8bit_row;
390 ERREXIT(cinfo, JERR_TGA_BADPARMS);
391 TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
393 case 2: /* RGB image */
394 switch (source->pixel_size) {
396 source->get_pixel_rows = get_16bit_row;
399 source->get_pixel_rows = get_24bit_row;
402 source->get_pixel_rows = get_32bit_row;
405 ERREXIT(cinfo, JERR_TGA_BADPARMS);
408 TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
410 case 3: /* Grayscale image */
412 cinfo->in_color_space = JCS_GRAYSCALE;
413 if (source->pixel_size == 1)
414 source->get_pixel_rows = get_8bit_gray_row;
416 ERREXIT(cinfo, JERR_TGA_BADPARMS);
417 TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
420 ERREXIT(cinfo, JERR_TGA_BADPARMS);
425 /* Create a virtual array to buffer the upside-down image. */
426 source->whole_image = (*cinfo->mem->request_virt_sarray)
427 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
428 (JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1);
429 if (cinfo->progress != NULL) {
430 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
431 progress->total_extra_passes++; /* count file input as separate pass */
433 /* source->pub.buffer will point to the virtual array. */
434 source->pub.buffer_height = 1; /* in case anyone looks at it */
435 source->pub.get_pixel_rows = preload_image;
437 /* Don't need a virtual array, but do need a one-row input buffer. */
438 source->whole_image = NULL;
439 source->pub.buffer = (*cinfo->mem->alloc_sarray)
440 ((j_common_ptr) cinfo, JPOOL_IMAGE,
441 (JDIMENSION) width * components, (JDIMENSION) 1);
442 source->pub.buffer_height = 1;
443 source->pub.get_pixel_rows = source->get_pixel_rows;
446 while (idlen--) /* Throw away ID field */
447 (void) read_byte(source);
450 if (maplen > 256 || GET_2B(3) != 0)
451 ERREXIT(cinfo, JERR_TGA_BADCMAP);
452 /* Allocate space to store the colormap */
453 source->colormap = (*cinfo->mem->alloc_sarray)
454 ((j_common_ptr) cinfo, JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3);
455 /* and read it from the file */
456 read_colormap(source, (int) maplen, UCH(targaheader[7]));
458 if (cmaptype) /* but you promised a cmap! */
459 ERREXIT(cinfo, JERR_TGA_BADPARMS);
460 source->colormap = NULL;
463 cinfo->input_components = components;
464 cinfo->data_precision = 8;
465 cinfo->image_width = width;
466 cinfo->image_height = height;
471 * Finish up at the end of the file.
475 finish_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
482 * The module selection routine for Targa format input.
485 GLOBAL(cjpeg_source_ptr)
486 jinit_read_targa (j_compress_ptr cinfo)
488 tga_source_ptr source;
490 /* Create module interface object */
491 source = (tga_source_ptr)
492 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
493 sizeof(tga_source_struct));
494 source->cinfo = cinfo; /* make back link for subroutines */
495 /* Fill in method ptrs, except get_pixel_rows which start_input sets */
496 source->pub.start_input = start_input_tga;
497 source->pub.finish_input = finish_input_tga;
499 return (cjpeg_source_ptr) source;
502 #endif /* TARGA_SUPPORTED */