summaryrefslogtreecommitdiff
path: root/jpeg/rdtarga.c
blob: 4c2cd26730a8af052bd674bb1aba7af0295a8d19 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
/*
 * rdtarga.c
 *
 * Copyright (C) 1991-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains routines to read input images in Targa format.
 *
 * These routines may need modification for non-Unix environments or
 * specialized applications.  As they stand, they assume input from
 * an ordinary stdio stream.  They further assume that reading begins
 * at the start of the file; start_input may need work if the
 * user interface has already read some data (e.g., to determine that
 * the file is indeed Targa format).
 *
 * Based on code contributed by Lee Daniel Crocker.
 */

#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */

#ifdef TARGA_SUPPORTED


/* Macros to deal with unsigned chars as efficiently as compiler allows */

#ifdef HAVE_UNSIGNED_CHAR
typedef unsigned char U_CHAR;
#define UCH(x)	((int) (x))
#else /* !HAVE_UNSIGNED_CHAR */
#ifdef CHAR_IS_UNSIGNED
typedef char U_CHAR;
#define UCH(x)	((int) (x))
#else
typedef char U_CHAR;
#define UCH(x)	((int) (x) & 0xFF)
#endif
#endif /* HAVE_UNSIGNED_CHAR */


#define	ReadOK(file,buffer,len)	(JFREAD(file,buffer,len) == ((size_t) (len)))


/* Private version of data source object */

typedef struct _tga_source_struct * tga_source_ptr;

typedef struct _tga_source_struct {
  struct cjpeg_source_struct pub; /* public fields */

  j_compress_ptr cinfo;		/* back link saves passing separate parm */

  JSAMPARRAY colormap;		/* Targa colormap (converted to my format) */

  jvirt_sarray_ptr whole_image;	/* Needed if funny input row order */
  JDIMENSION current_row;	/* Current logical row number to read */

  /* Pointer to routine to extract next Targa pixel from input file */
  JMETHOD(void, read_pixel, (tga_source_ptr sinfo));

  /* Result of read_pixel is delivered here: */
  U_CHAR tga_pixel[4];

  int pixel_size;		/* Bytes per Targa pixel (1 to 4) */

  /* State info for reading RLE-coded pixels; both counts must be init to 0 */
  int block_count;		/* # of pixels remaining in RLE block */
  int dup_pixel_count;		/* # of times to duplicate previous pixel */

  /* This saves the correct pixel-row-expansion method for preload_image */
  JMETHOD(JDIMENSION, get_pixel_rows, (j_compress_ptr cinfo,
				       cjpeg_source_ptr sinfo));
} tga_source_struct;


/* For expanding 5-bit pixel values to 8-bit with best rounding */

static const UINT8 c5to8bits[32] = {
    0,   8,  16,  25,  33,  41,  49,  58,
   66,  74,  82,  90,  99, 107, 115, 123,
  132, 140, 148, 156, 165, 173, 181, 189,
  197, 206, 214, 222, 230, 239, 247, 255
};



LOCAL(int)
read_byte (tga_source_ptr sinfo)
/* Read next byte from Targa file */
{
  register FILE *infile = sinfo->pub.input_file;
  register int c;

  if ((c = getc(infile)) == EOF)
    ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
  return c;
}


LOCAL(void)
read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize)
/* Read the colormap from a Targa file */
{
  int i;

  /* Presently only handles 24-bit BGR format */
  if (mapentrysize != 24)
    ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);

  for (i = 0; i < cmaplen; i++) {
    sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
    sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
    sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
  }
}


/*
 * read_pixel methods: get a single pixel from Targa file into tga_pixel[]
 */

METHODDEF(void)
read_non_rle_pixel (tga_source_ptr sinfo)
/* Read one Targa pixel from the input file; no RLE expansion */
{
  register FILE *infile = sinfo->pub.input_file;
  register int i;

  for (i = 0; i < sinfo->pixel_size; i++) {
    sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
  }
}


METHODDEF(void)
read_rle_pixel (tga_source_ptr sinfo)
/* Read one Targa pixel from the input file, expanding RLE data as needed */
{
  register FILE *infile = sinfo->pub.input_file;
  register int i;

  /* Duplicate previously read pixel? */
  if (sinfo->dup_pixel_count > 0) {
    sinfo->dup_pixel_count--;
    return;
  }

  /* Time to read RLE block header? */
  if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
    i = read_byte(sinfo);
    if (i & 0x80) {		/* Start of duplicate-pixel block? */
      sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
      sinfo->block_count = 0;	/* then read new block header */
    } else {
      sinfo->block_count = i & 0x7F; /* number of pixels after this one */
    }
  }

  /* Read next pixel */
  for (i = 0; i < sinfo->pixel_size; i++) {
    sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
  }
}


/*
 * Read one row of pixels.
 *
 * We provide several different versions depending on input file format.
 */


METHODDEF(JDIMENSION)
get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 8-bit grayscale pixels */
{
  tga_source_ptr source = (tga_source_ptr) sinfo;
  register JSAMPROW ptr;
  register JDIMENSION col;
  
  ptr = source->pub.buffer[0];
  for (col = cinfo->image_width; col > 0; col--) {
    (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
    *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
  }
  return 1;
}

METHODDEF(JDIMENSION)
get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 8-bit colormap indexes */
{
  tga_source_ptr source = (tga_source_ptr) sinfo;
  register int t;
  register JSAMPROW ptr;
  register JDIMENSION col;
  register JSAMPARRAY colormap = source->colormap;

  ptr = source->pub.buffer[0];
  for (col = cinfo->image_width; col > 0; col--) {
    (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
    t = UCH(source->tga_pixel[0]);
    *ptr++ = colormap[0][t];
    *ptr++ = colormap[1][t];
    *ptr++ = colormap[2][t];
  }
  return 1;
}

METHODDEF(JDIMENSION)
get_16bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 16-bit pixels */
{
  tga_source_ptr source = (tga_source_ptr) sinfo;
  register int t;
  register JSAMPROW ptr;
  register JDIMENSION col;
  
  ptr = source->pub.buffer[0];
  for (col = cinfo->image_width; col > 0; col--) {
    (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
    t = UCH(source->tga_pixel[0]);
    t += UCH(source->tga_pixel[1]) << 8;
    /* We expand 5 bit data to 8 bit sample width.
     * The format of the 16-bit (LSB first) input word is
     *     xRRRRRGGGGGBBBBB
     */
    ptr[2] = (JSAMPLE) c5to8bits[t & 0x1F];
    t >>= 5;
    ptr[1] = (JSAMPLE) c5to8bits[t & 0x1F];
    t >>= 5;
    ptr[0] = (JSAMPLE) c5to8bits[t & 0x1F];
    ptr += 3;
  }
  return 1;
}

METHODDEF(JDIMENSION)
get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 24-bit pixels */
{
  tga_source_ptr source = (tga_source_ptr) sinfo;
  register JSAMPROW ptr;
  register JDIMENSION col;
  
  ptr = source->pub.buffer[0];
  for (col = cinfo->image_width; col > 0; col--) {
    (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
    *ptr++ = (JSAMPLE) UCH(source->tga_pixel[2]); /* change BGR to RGB order */
    *ptr++ = (JSAMPLE) UCH(source->tga_pixel[1]);
    *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
  }
  return 1;
}

/*
 * Targa also defines a 32-bit pixel format with order B,G,R,A.
 * We presently ignore the attribute byte, so the code for reading
 * these pixels is identical to the 24-bit routine above.
 * This works because the actual pixel length is only known to read_pixel.
 */

#define get_32bit_row  get_24bit_row


/*
 * This method is for re-reading the input data in standard top-down
 * row order.  The entire image has already been read into whole_image
 * with proper conversion of pixel format, but it's in a funny row order.
 */

METHODDEF(JDIMENSION)
get_memory_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
  tga_source_ptr source = (tga_source_ptr) sinfo;
  JDIMENSION source_row;

  /* Compute row of source that maps to current_row of normal order */
  /* For now, assume image is bottom-up and not interlaced. */
  /* NEEDS WORK to support interlaced images! */
  source_row = cinfo->image_height - source->current_row - 1;

  /* Fetch that row from virtual array */
  source->pub.buffer = (*cinfo->mem->access_virt_sarray)
    ((j_common_ptr) cinfo, source->whole_image,
     source_row, (JDIMENSION) 1, FALSE);

  source->current_row++;
  return 1;
}


/*
 * This method loads the image into whole_image during the first call on
 * get_pixel_rows.  The get_pixel_rows pointer is then adjusted to call
 * get_memory_row on subsequent calls.
 */

METHODDEF(JDIMENSION)
preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
  tga_source_ptr source = (tga_source_ptr) sinfo;
  JDIMENSION row;
  cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;

  /* Read the data into a virtual array in input-file row order. */
  for (row = 0; row < cinfo->image_height; row++) {
    if (progress != NULL) {
      progress->pub.pass_counter = (long) row;
      progress->pub.pass_limit = (long) cinfo->image_height;
      (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
    }
    source->pub.buffer = (*cinfo->mem->access_virt_sarray)
      ((j_common_ptr) cinfo, source->whole_image, row, (JDIMENSION) 1, TRUE);
    (*source->get_pixel_rows) (cinfo, sinfo);
  }
  if (progress != NULL)
    progress->completed_extra_passes++;

  /* Set up to read from the virtual array in unscrambled order */
  source->pub.get_pixel_rows = get_memory_row;
  source->current_row = 0;
  /* And read the first row */
  return get_memory_row(cinfo, sinfo);
}


/*
 * Read the file header; return image size and component count.
 */

METHODDEF(void)
start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
  tga_source_ptr source = (tga_source_ptr) sinfo;
  U_CHAR targaheader[18];
  int idlen, cmaptype, subtype, flags, interlace_type, components;
  unsigned int width, height, maplen;
  boolean is_bottom_up;

#define GET_2B(offset)	((unsigned int) UCH(targaheader[offset]) + \
			 (((unsigned int) UCH(targaheader[offset+1])) << 8))

  if (! ReadOK(source->pub.input_file, targaheader, 18))
    ERREXIT(cinfo, JERR_INPUT_EOF);

  /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
  if (targaheader[16] == 15)
    targaheader[16] = 16;

  idlen = UCH(targaheader[0]);
  cmaptype = UCH(targaheader[1]);
  subtype = UCH(targaheader[2]);
  maplen = GET_2B(5);
  width = GET_2B(12);
  height = GET_2B(14);
  source->pixel_size = UCH(targaheader[16]) >> 3;
  flags = UCH(targaheader[17]);	/* Image Descriptor byte */

  is_bottom_up = ((flags & 0x20) == 0);	/* bit 5 set => top-down */
  interlace_type = flags >> 6;	/* bits 6/7 are interlace code */

  if (cmaptype > 1 ||		/* cmaptype must be 0 or 1 */
      source->pixel_size < 1 || source->pixel_size > 4 ||
      (UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
      interlace_type != 0)	/* currently don't allow interlaced image */
    ERREXIT(cinfo, JERR_TGA_BADPARMS);
  
  if (subtype > 8) {
    /* It's an RLE-coded file */
    source->read_pixel = read_rle_pixel;
    source->block_count = source->dup_pixel_count = 0;
    subtype -= 8;
  } else {
    /* Non-RLE file */
    source->read_pixel = read_non_rle_pixel;
  }

  /* Now should have subtype 1, 2, or 3 */
  components = 3;		/* until proven different */
  cinfo->in_color_space = JCS_RGB;

  switch (subtype) {
  case 1:			/* Colormapped image */
    if (source->pixel_size == 1 && cmaptype == 1)
      source->get_pixel_rows = get_8bit_row;
    else
      ERREXIT(cinfo, JERR_TGA_BADPARMS);
    TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
    break;
  case 2:			/* RGB image */
    switch (source->pixel_size) {
    case 2:
      source->get_pixel_rows = get_16bit_row;
      break;
    case 3:
      source->get_pixel_rows = get_24bit_row;
      break;
    case 4:
      source->get_pixel_rows = get_32bit_row;
      break;
    default:
      ERREXIT(cinfo, JERR_TGA_BADPARMS);
      break;
    }
    TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
    break;
  case 3:			/* Grayscale image */
    components = 1;
    cinfo->in_color_space = JCS_GRAYSCALE;
    if (source->pixel_size == 1)
      source->get_pixel_rows = get_8bit_gray_row;
    else
      ERREXIT(cinfo, JERR_TGA_BADPARMS);
    TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
    break;
  default:
    ERREXIT(cinfo, JERR_TGA_BADPARMS);
    break;
  }

  if (is_bottom_up) {
    /* Create a virtual array to buffer the upside-down image. */
    source->whole_image = (*cinfo->mem->request_virt_sarray)
      ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
       (JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1);
    if (cinfo->progress != NULL) {
      cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
      progress->total_extra_passes++; /* count file input as separate pass */
    }
    /* source->pub.buffer will point to the virtual array. */
    source->pub.buffer_height = 1; /* in case anyone looks at it */
    source->pub.get_pixel_rows = preload_image;
  } else {
    /* Don't need a virtual array, but do need a one-row input buffer. */
    source->whole_image = NULL;
    source->pub.buffer = (*cinfo->mem->alloc_sarray)
      ((j_common_ptr) cinfo, JPOOL_IMAGE,
       (JDIMENSION) width * components, (JDIMENSION) 1);
    source->pub.buffer_height = 1;
    source->pub.get_pixel_rows = source->get_pixel_rows;
  }
  
  while (idlen--)		/* Throw away ID field */
    (void) read_byte(source);

  if (maplen > 0) {
    if (maplen > 256 || GET_2B(3) != 0)
      ERREXIT(cinfo, JERR_TGA_BADCMAP);
    /* Allocate space to store the colormap */
    source->colormap = (*cinfo->mem->alloc_sarray)
      ((j_common_ptr) cinfo, JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3);
    /* and read it from the file */
    read_colormap(source, (int) maplen, UCH(targaheader[7]));
  } else {
    if (cmaptype)		/* but you promised a cmap! */
      ERREXIT(cinfo, JERR_TGA_BADPARMS);
    source->colormap = NULL;
  }

  cinfo->input_components = components;
  cinfo->data_precision = 8;
  cinfo->image_width = width;
  cinfo->image_height = height;
}


/*
 * Finish up at the end of the file.
 */

METHODDEF(void)
finish_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
  /* no work */
}


/*
 * The module selection routine for Targa format input.
 */

GLOBAL(cjpeg_source_ptr)
jinit_read_targa (j_compress_ptr cinfo)
{
  tga_source_ptr source;

  /* Create module interface object */
  source = (tga_source_ptr)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				  SIZEOF(tga_source_struct));
  source->cinfo = cinfo;	/* make back link for subroutines */
  /* Fill in method ptrs, except get_pixel_rows which start_input sets */
  source->pub.start_input = start_input_tga;
  source->pub.finish_input = finish_input_tga;

  return (cjpeg_source_ptr) source;
}

#endif /* TARGA_SUPPORTED */