4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1996, Thomas G. Lane.
6 * Modified 2017 by Guido Vollbeding.
7 * libjpeg-turbo Modifications:
8 * Copyright (C) 2018, D. R. Commander.
9 * For conditions of distribution and use, see the accompanying README.ijg
12 * This file contains routines to read input images in Targa format.
14 * These routines may need modification for non-Unix environments or
15 * specialized applications. As they stand, they assume input from
16 * an ordinary stdio stream. They further assume that reading begins
17 * at the start of the file; start_input may need work if the
18 * user interface has already read some data (e.g., to determine that
19 * the file is indeed Targa format).
21 * Based on code contributed by Lee Daniel Crocker.
24 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
26 #ifdef TARGA_SUPPORTED
29 /* Macros to deal with unsigned chars as efficiently as compiler allows */
31 #ifdef HAVE_UNSIGNED_CHAR
32 typedef unsigned char U_CHAR;
33 #define UCH(x) ((int)(x))
34 #else /* !HAVE_UNSIGNED_CHAR */
35 #ifdef __CHAR_UNSIGNED__
37 #define UCH(x) ((int)(x))
40 #define UCH(x) ((int)(x) & 0xFF)
42 #endif /* HAVE_UNSIGNED_CHAR */
45 #define ReadOK(file, buffer, len) \
46 (JFREAD(file, buffer, len) == ((size_t)(len)))
49 /* Private version of data source object */
51 typedef struct _tga_source_struct *tga_source_ptr;
53 typedef struct _tga_source_struct {
54 struct cjpeg_source_struct pub; /* public fields */
56 j_compress_ptr cinfo; /* back link saves passing separate parm */
58 JSAMPARRAY colormap; /* Targa colormap (converted to my format) */
60 jvirt_sarray_ptr whole_image; /* Needed if funny input row order */
61 JDIMENSION current_row; /* Current logical row number to read */
63 /* Pointer to routine to extract next Targa pixel from input file */
64 void (*read_pixel) (tga_source_ptr sinfo);
66 /* Result of read_pixel is delivered here: */
69 int pixel_size; /* Bytes per Targa pixel (1 to 4) */
70 int cmap_length; /* colormap length */
72 /* State info for reading RLE-coded pixels; both counts must be init to 0 */
73 int block_count; /* # of pixels remaining in RLE block */
74 int dup_pixel_count; /* # of times to duplicate previous pixel */
76 /* This saves the correct pixel-row-expansion method for preload_image */
77 JDIMENSION (*get_pixel_rows) (j_compress_ptr cinfo, cjpeg_source_ptr sinfo);
81 /* For expanding 5-bit pixel values to 8-bit with best rounding */
83 static const UINT8 c5to8bits[32] = {
84 0, 8, 16, 25, 33, 41, 49, 58,
85 66, 74, 82, 90, 99, 107, 115, 123,
86 132, 140, 148, 156, 165, 173, 181, 189,
87 197, 206, 214, 222, 230, 239, 247, 255
93 read_byte(tga_source_ptr sinfo)
94 /* Read next byte from Targa file */
96 register FILE *infile = sinfo->pub.input_file;
99 if ((c = getc(infile)) == EOF)
100 ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
106 read_colormap(tga_source_ptr sinfo, int cmaplen, int mapentrysize)
107 /* Read the colormap from a Targa file */
111 /* Presently only handles 24-bit BGR format */
112 if (mapentrysize != 24)
113 ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
115 for (i = 0; i < cmaplen; i++) {
116 sinfo->colormap[2][i] = (JSAMPLE)read_byte(sinfo);
117 sinfo->colormap[1][i] = (JSAMPLE)read_byte(sinfo);
118 sinfo->colormap[0][i] = (JSAMPLE)read_byte(sinfo);
124 * read_pixel methods: get a single pixel from Targa file into tga_pixel[]
128 read_non_rle_pixel(tga_source_ptr sinfo)
129 /* Read one Targa pixel from the input file; no RLE expansion */
133 for (i = 0; i < sinfo->pixel_size; i++) {
134 sinfo->tga_pixel[i] = (U_CHAR)read_byte(sinfo);
140 read_rle_pixel(tga_source_ptr sinfo)
141 /* Read one Targa pixel from the input file, expanding RLE data as needed */
145 /* Duplicate previously read pixel? */
146 if (sinfo->dup_pixel_count > 0) {
147 sinfo->dup_pixel_count--;
151 /* Time to read RLE block header? */
152 if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
153 i = read_byte(sinfo);
154 if (i & 0x80) { /* Start of duplicate-pixel block? */
155 sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
156 sinfo->block_count = 0; /* then read new block header */
158 sinfo->block_count = i & 0x7F; /* number of pixels after this one */
162 /* Read next pixel */
163 for (i = 0; i < sinfo->pixel_size; i++) {
164 sinfo->tga_pixel[i] = (U_CHAR)read_byte(sinfo);
170 * Read one row of pixels.
172 * We provide several different versions depending on input file format.
176 METHODDEF(JDIMENSION)
177 get_8bit_gray_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
178 /* This version is for reading 8-bit grayscale pixels */
180 tga_source_ptr source = (tga_source_ptr)sinfo;
181 register JSAMPROW ptr;
182 register JDIMENSION col;
184 ptr = source->pub.buffer[0];
185 for (col = cinfo->image_width; col > 0; col--) {
186 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
187 *ptr++ = (JSAMPLE)UCH(source->tga_pixel[0]);
192 METHODDEF(JDIMENSION)
193 get_8bit_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
194 /* This version is for reading 8-bit colormap indexes */
196 tga_source_ptr source = (tga_source_ptr)sinfo;
198 register JSAMPROW ptr;
199 register JDIMENSION col;
200 register JSAMPARRAY colormap = source->colormap;
201 int cmaplen = source->cmap_length;
203 ptr = source->pub.buffer[0];
204 for (col = cinfo->image_width; col > 0; col--) {
205 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
206 t = UCH(source->tga_pixel[0]);
208 ERREXIT(cinfo, JERR_TGA_BADPARMS);
209 *ptr++ = colormap[0][t];
210 *ptr++ = colormap[1][t];
211 *ptr++ = colormap[2][t];
216 METHODDEF(JDIMENSION)
217 get_16bit_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
218 /* This version is for reading 16-bit pixels */
220 tga_source_ptr source = (tga_source_ptr)sinfo;
222 register JSAMPROW ptr;
223 register JDIMENSION col;
225 ptr = source->pub.buffer[0];
226 for (col = cinfo->image_width; col > 0; col--) {
227 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
228 t = UCH(source->tga_pixel[0]);
229 t += UCH(source->tga_pixel[1]) << 8;
230 /* We expand 5 bit data to 8 bit sample width.
231 * The format of the 16-bit (LSB first) input word is
234 ptr[2] = (JSAMPLE)c5to8bits[t & 0x1F];
236 ptr[1] = (JSAMPLE)c5to8bits[t & 0x1F];
238 ptr[0] = (JSAMPLE)c5to8bits[t & 0x1F];
244 METHODDEF(JDIMENSION)
245 get_24bit_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
246 /* This version is for reading 24-bit pixels */
248 tga_source_ptr source = (tga_source_ptr)sinfo;
249 register JSAMPROW ptr;
250 register JDIMENSION col;
252 ptr = source->pub.buffer[0];
253 for (col = cinfo->image_width; col > 0; col--) {
254 (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
255 *ptr++ = (JSAMPLE)UCH(source->tga_pixel[2]); /* change BGR to RGB order */
256 *ptr++ = (JSAMPLE)UCH(source->tga_pixel[1]);
257 *ptr++ = (JSAMPLE)UCH(source->tga_pixel[0]);
263 * Targa also defines a 32-bit pixel format with order B,G,R,A.
264 * We presently ignore the attribute byte, so the code for reading
265 * these pixels is identical to the 24-bit routine above.
266 * This works because the actual pixel length is only known to read_pixel.
269 #define get_32bit_row get_24bit_row
273 * This method is for re-reading the input data in standard top-down
274 * row order. The entire image has already been read into whole_image
275 * with proper conversion of pixel format, but it's in a funny row order.
278 METHODDEF(JDIMENSION)
279 get_memory_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
281 tga_source_ptr source = (tga_source_ptr)sinfo;
282 JDIMENSION source_row;
284 /* Compute row of source that maps to current_row of normal order */
285 /* For now, assume image is bottom-up and not interlaced. */
286 /* NEEDS WORK to support interlaced images! */
287 source_row = cinfo->image_height - source->current_row - 1;
289 /* Fetch that row from virtual array */
290 source->pub.buffer = (*cinfo->mem->access_virt_sarray)
291 ((j_common_ptr)cinfo, source->whole_image,
292 source_row, (JDIMENSION)1, FALSE);
294 source->current_row++;
300 * This method loads the image into whole_image during the first call on
301 * get_pixel_rows. The get_pixel_rows pointer is then adjusted to call
302 * get_memory_row on subsequent calls.
305 METHODDEF(JDIMENSION)
306 preload_image(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
308 tga_source_ptr source = (tga_source_ptr)sinfo;
310 cd_progress_ptr progress = (cd_progress_ptr)cinfo->progress;
312 /* Read the data into a virtual array in input-file row order. */
313 for (row = 0; row < cinfo->image_height; row++) {
314 if (progress != NULL) {
315 progress->pub.pass_counter = (long)row;
316 progress->pub.pass_limit = (long)cinfo->image_height;
317 (*progress->pub.progress_monitor) ((j_common_ptr)cinfo);
319 source->pub.buffer = (*cinfo->mem->access_virt_sarray)
320 ((j_common_ptr)cinfo, source->whole_image, row, (JDIMENSION)1, TRUE);
321 (*source->get_pixel_rows) (cinfo, sinfo);
323 if (progress != NULL)
324 progress->completed_extra_passes++;
326 /* Set up to read from the virtual array in unscrambled order */
327 source->pub.get_pixel_rows = get_memory_row;
328 source->current_row = 0;
329 /* And read the first row */
330 return get_memory_row(cinfo, sinfo);
335 * Read the file header; return image size and component count.
339 start_input_tga(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
341 tga_source_ptr source = (tga_source_ptr)sinfo;
342 U_CHAR targaheader[18];
343 int idlen, cmaptype, subtype, flags, interlace_type, components;
344 unsigned int width, height, maplen;
345 boolean is_bottom_up;
347 #define GET_2B(offset) \
348 ((unsigned int)UCH(targaheader[offset]) + \
349 (((unsigned int)UCH(targaheader[offset + 1])) << 8))
351 if (!ReadOK(source->pub.input_file, targaheader, 18))
352 ERREXIT(cinfo, JERR_INPUT_EOF);
354 /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
355 if (targaheader[16] == 15)
356 targaheader[16] = 16;
358 idlen = UCH(targaheader[0]);
359 cmaptype = UCH(targaheader[1]);
360 subtype = UCH(targaheader[2]);
364 source->pixel_size = UCH(targaheader[16]) >> 3;
365 flags = UCH(targaheader[17]); /* Image Descriptor byte */
367 is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
368 interlace_type = flags >> 6; /* bits 6/7 are interlace code */
370 if (cmaptype > 1 || /* cmaptype must be 0 or 1 */
371 source->pixel_size < 1 || source->pixel_size > 4 ||
372 (UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
373 interlace_type != 0 || /* currently don't allow interlaced image */
374 width == 0 || height == 0) /* image width/height must be non-zero */
375 ERREXIT(cinfo, JERR_TGA_BADPARMS);
378 /* It's an RLE-coded file */
379 source->read_pixel = read_rle_pixel;
380 source->block_count = source->dup_pixel_count = 0;
384 source->read_pixel = read_non_rle_pixel;
387 /* Now should have subtype 1, 2, or 3 */
388 components = 3; /* until proven different */
389 cinfo->in_color_space = JCS_RGB;
392 case 1: /* Colormapped image */
393 if (source->pixel_size == 1 && cmaptype == 1)
394 source->get_pixel_rows = get_8bit_row;
396 ERREXIT(cinfo, JERR_TGA_BADPARMS);
397 TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
399 case 2: /* RGB image */
400 switch (source->pixel_size) {
402 source->get_pixel_rows = get_16bit_row;
405 source->get_pixel_rows = get_24bit_row;
408 source->get_pixel_rows = get_32bit_row;
411 ERREXIT(cinfo, JERR_TGA_BADPARMS);
414 TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
416 case 3: /* Grayscale image */
418 cinfo->in_color_space = JCS_GRAYSCALE;
419 if (source->pixel_size == 1)
420 source->get_pixel_rows = get_8bit_gray_row;
422 ERREXIT(cinfo, JERR_TGA_BADPARMS);
423 TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
426 ERREXIT(cinfo, JERR_TGA_BADPARMS);
431 /* Create a virtual array to buffer the upside-down image. */
432 source->whole_image = (*cinfo->mem->request_virt_sarray)
433 ((j_common_ptr)cinfo, JPOOL_IMAGE, FALSE,
434 (JDIMENSION)width * components, (JDIMENSION)height, (JDIMENSION)1);
435 if (cinfo->progress != NULL) {
436 cd_progress_ptr progress = (cd_progress_ptr)cinfo->progress;
437 progress->total_extra_passes++; /* count file input as separate pass */
439 /* source->pub.buffer will point to the virtual array. */
440 source->pub.buffer_height = 1; /* in case anyone looks at it */
441 source->pub.get_pixel_rows = preload_image;
443 /* Don't need a virtual array, but do need a one-row input buffer. */
444 source->whole_image = NULL;
445 source->pub.buffer = (*cinfo->mem->alloc_sarray)
446 ((j_common_ptr)cinfo, JPOOL_IMAGE,
447 (JDIMENSION)width * components, (JDIMENSION)1);
448 source->pub.buffer_height = 1;
449 source->pub.get_pixel_rows = source->get_pixel_rows;
452 while (idlen--) /* Throw away ID field */
453 (void)read_byte(source);
456 if (maplen > 256 || GET_2B(3) != 0)
457 ERREXIT(cinfo, JERR_TGA_BADCMAP);
458 /* Allocate space to store the colormap */
459 source->colormap = (*cinfo->mem->alloc_sarray)
460 ((j_common_ptr)cinfo, JPOOL_IMAGE, (JDIMENSION)maplen, (JDIMENSION)3);
461 source->cmap_length = (int)maplen;
462 /* and read it from the file */
463 read_colormap(source, (int)maplen, UCH(targaheader[7]));
465 if (cmaptype) /* but you promised a cmap! */
466 ERREXIT(cinfo, JERR_TGA_BADPARMS);
467 source->colormap = NULL;
468 source->cmap_length = 0;
471 cinfo->input_components = components;
472 cinfo->data_precision = 8;
473 cinfo->image_width = width;
474 cinfo->image_height = height;
479 * Finish up at the end of the file.
483 finish_input_tga(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
490 * The module selection routine for Targa format input.
493 GLOBAL(cjpeg_source_ptr)
494 jinit_read_targa(j_compress_ptr cinfo)
496 tga_source_ptr source;
498 /* Create module interface object */
499 source = (tga_source_ptr)
500 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
501 sizeof(tga_source_struct));
502 source->cinfo = cinfo; /* make back link for subroutines */
503 /* Fill in method ptrs, except get_pixel_rows which start_input sets */
504 source->pub.start_input = start_input_tga;
505 source->pub.finish_input = finish_input_tga;
507 return (cjpeg_source_ptr)source;
510 #endif /* TARGA_SUPPORTED */