io-pnm.c 22.5 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
/* GdkPixbuf library - PNM image loader
 *
 * Copyright (C) 1999 Red Hat, Inc.
 *
 * Authors: Michael Fulbright <drmike@redhat.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

23 24 25 26 27 28 29 30 31
/* Notes (11/05/99):
 *
 * raw pnm, pgm, and pbm files will load now.
 *
 * ascii support coming soon.
 *
 * next will be incremental loading.
 */
 
32 33

#include <config.h>
34
#include <ctype.h>
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
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <setjmp.h>
#include <jpeglib.h>
#include "gdk-pixbuf.h"
#include "gdk-pixbuf-io.h"




#define PNM_BUF_SIZE 4096

#define PNM_SUSPEND    0
#define PNM_OK         1
#define PNM_FATAL_ERR  -1

typedef enum {
	PNM_FORMAT_PGM,
	PNM_FORMAT_PGM_RAW,
	PNM_FORMAT_PPM,
	PNM_FORMAT_PPM_RAW,
	PNM_FORMAT_PBM,
	PNM_FORMAT_PBM_RAW
} PnmFormat;

typedef struct {
	guchar    buffer[PNM_BUF_SIZE];
	guchar    *next_byte;
	guint     bytes_left;
} PnmIOBuffer;

typedef struct {
	ModuleUpdatedNotifyFunc  updated_func;
	ModulePreparedNotifyFunc prepared_func;
	gpointer                 user_data;
	
	GdkPixbuf                *pixbuf;
	guchar                   *pixels; /* incoming pixel data buffer */
	guchar                   *dptr;   /* current position in pixbuf */

	PnmIOBuffer              inbuf;

	guint                    width;
	guint                    height;
80
	guint                    maxval;
81 82 83 84 85 86 87 88 89 90 91 92 93 94
	PnmFormat                type;

	guint                    output_row;  /* last row to be completed */
	guint                    output_col;
	gboolean                 did_prescan;  /* are we in image data yet? */
	gboolean                 got_header;  /* have we loaded jpeg header? */
} PnmLoaderContext;

GdkPixbuf *image_load (FILE *f);
gpointer image_begin_load (ModulePreparedNotifyFunc func, 
			   ModuleUpdatedNotifyFunc func2, gpointer user_data);
void image_stop_load (gpointer context);
gboolean image_load_increment(gpointer context, guchar *buf, guint size);

95 96
static void explode_bitmap_into_buf (PnmLoaderContext *context);
static void explode_gray_into_buf (PnmLoaderContext *context);
97 98 99 100 101 102 103 104 105

/* Destroy notification function for the libart pixbuf */
static void
free_buffer (gpointer user_data, gpointer data)
{
	free (data);
}


106 107 108 109 110
/* explode bitmap data into rgb components         */
/* we need to know what the row so we can          */
/* do sub-byte expansion (since 1 byte = 8 pixels) */
/* context->dptr MUST point at first byte in incoming data  */
/* which corresponds to first pixel of row y       */
111
static void
112
explode_bitmap_into_buf (PnmLoaderContext *context)
113
{
114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130
	gint j;
	guchar *from, *to, data;
	gint bit;
	guchar *dptr;
	gint wid, x, y;

	g_return_if_fail (context != NULL);
	g_return_if_fail (context->dptr != NULL);

	/* I'm no clever bit-hacker so I'm sure this can be optimized */
	dptr = context->dptr;
	y    = context->output_row;
	wid  = context->width;

	from = dptr + (wid - 1)/8;
	to   = dptr + (wid - 1) * 3;
	bit  = 7 - (((y+1)*wid - 1) % 8);
131

132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149
	/* get first byte and align properly */
	data = from[0];
	for (j = 0; j < bit; j++, data >>= 1);

	for (x = wid-1; x >= 0; x--) {

		to[0] = to[1] = to[2] = (data & 1) ? 0x00 : 0xff;

		to -= 3;
		bit++;

		if (bit > 7) {
			from--;
			data = from[0];
			bit = 0;
		} else {
			data >>= 1;
		}
150 151 152 153 154
	}
}

/* explode gray image row into rgb components in pixbuf */
static void
155
explode_gray_into_buf (PnmLoaderContext *context)
156
{
157
	gint j;
158
	guchar *from, *to;
159
	guint w;
160

161 162
	g_return_if_fail (context != NULL);
	g_return_if_fail (context->dptr != NULL);
163 164 165 166

	/* Expand grey->colour.  Expand from the end of the
	 * memory down, so we can use the same buffer.
	 */
167 168 169
	w = context->width;
	from = context->dptr + w - 1;
	to = context->dptr + (w - 1) * 3;
170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190
	for (j = w - 1; j >= 0; j--) {
		to[0] = from[0];
		to[1] = from[0];
		to[2] = from[0];
		to -= 3;
		from--;
	}
}

/* skip over whitespace in file from current pos.                      */
/* also skips comments                                                 */
/* returns pointer to first non-whitespace char hit or, or NULL if     */
/* we ran out of data w/o hitting a whitespace                         */
/* internal pointer in inbuf isnt moved ahead in this case             */
static guchar *
skip_ahead_whitespace (PnmIOBuffer *inbuf)
{
	gboolean in_comment;
	guchar *ptr;
	guint num_left;
	
191 192
	g_return_val_if_fail (inbuf != NULL, NULL);
	g_return_val_if_fail (inbuf->next_byte != NULL, NULL);
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
	
	in_comment = FALSE;
	num_left = inbuf->bytes_left;
	ptr      = inbuf->next_byte;
	while (num_left > 0) {
		if (in_comment) {
			if (*ptr == '\n')
				in_comment = FALSE;
		} else if (*ptr == '#') {
			in_comment = TRUE;
		} else if (!isspace (*ptr)) {
			inbuf->bytes_left -= (ptr-inbuf->next_byte);
			inbuf->next_byte   = ptr;
			return ptr;
		}
		ptr ++;
		num_left--;
	}
	return NULL;
}

/* reads into buffer until we hit whitespace in file from current pos,     */
/* return NULL if ran out of data                                          */
/* advances inbuf if successful                                            */
static guchar *
read_til_whitespace (PnmIOBuffer *inbuf, guchar *buf, guint size)
{
	guchar *p;
	guchar *ptr;
	guint num_left;

224 225
	g_return_val_if_fail (inbuf != NULL, NULL);
	g_return_val_if_fail (inbuf->next_byte != NULL, NULL);
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
	
	p = buf;
	num_left = inbuf->bytes_left;
	ptr      = inbuf->next_byte;
	while (num_left > 0 && (p-buf)+1 < size) {
		if (isspace (*ptr)) {
			*p = '\0';
			inbuf->bytes_left = num_left;
			inbuf->next_byte  = ptr;
			return ptr;
		} else {
			*p = *ptr;
			p++;
			ptr++;
			num_left--;
		}
	}
	return NULL;
}

/* read next number from buffer  */
/* -1 if failed, 0 if successful */
static gint
read_next_number (PnmIOBuffer *inbuf, guint *value)
{
	guchar *tmpptr;
	guchar *old_next_byte;
	gchar  *errptr;
	guint  old_bytes_left;
	guchar buf[128];

257 258 259
	g_return_val_if_fail (inbuf != NULL, -1);
	g_return_val_if_fail (inbuf->next_byte != NULL, -1);
	g_return_val_if_fail (value != NULL, -1);
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

	old_next_byte  = inbuf->next_byte;
	old_bytes_left = inbuf->bytes_left;

	if ((tmpptr = skip_ahead_whitespace (inbuf)) == NULL)
		return -1;

	if ((tmpptr = read_til_whitespace (inbuf, buf, 128)) == NULL) {
		inbuf->next_byte  = old_next_byte;
		inbuf->bytes_left = old_bytes_left;
		return -1;
	}
	
	*value = strtol (buf, &errptr, 10);

	if (*errptr != '\0') {
		inbuf->next_byte  = old_next_byte;
		inbuf->bytes_left = old_bytes_left;
		return -1;
	}

	return 0;
}

/* returns PNM_OK, PNM_SUSPEND, or PNM_FATAL_ERR */
static gint
pnm_read_header (PnmLoaderContext *context)
{
	guchar *old_next_byte;
	guint  old_bytes_left;
	PnmIOBuffer *inbuf;
	guint  w, h;
	gint rc;
	PnmFormat  type;

	g_return_val_if_fail (context != NULL, PNM_FATAL_ERR);

	inbuf = &context->inbuf;
	old_bytes_left = inbuf->bytes_left;
	old_next_byte  = inbuf->next_byte;
	
	/* file must start with a 'P' followed by a numeral */
	/* so loop till we get enough data to determine type*/
	if (inbuf->bytes_left < 2)
		return PNM_SUSPEND;
	
	if (*inbuf->next_byte != 'P')
		return PNM_FATAL_ERR;
	
	switch (*(inbuf->next_byte+1)) {
	case '1':
		type = PNM_FORMAT_PBM;
		break;
	case '2':
		type = PNM_FORMAT_PGM;
		break;
	case '3':
		type = PNM_FORMAT_PPM;
		break;
	case '4':
		type = PNM_FORMAT_PBM_RAW;
		break;
	case '5':
		type = PNM_FORMAT_PGM_RAW;
		break;
	case '6':
		type = PNM_FORMAT_PPM_RAW;
		break;
	default:
		return PNM_FATAL_ERR;
	}
	
	context->type = type;

	inbuf->next_byte  += 2;
	inbuf->bytes_left -= 2;
	
	/* now read remainder of header */
	if ((rc = read_next_number (inbuf, &w))) {
		inbuf->next_byte = old_next_byte;
		inbuf->bytes_left = old_bytes_left;
		return PNM_SUSPEND;
	}
	
	if ((rc = read_next_number (inbuf, &h))) {
		inbuf->next_byte = old_next_byte;
		inbuf->bytes_left = old_bytes_left;
		return PNM_SUSPEND;
	}
	
	context->width  = w;
	context->height = h;
	
	switch (type) {
	case PNM_FORMAT_PPM:
	case PNM_FORMAT_PPM_RAW:
	case PNM_FORMAT_PGM:
	case PNM_FORMAT_PGM_RAW:
358
		if ((rc = read_next_number (inbuf, &context->maxval)) < 0) {
359 360 361 362 363 364 365 366 367
			inbuf->next_byte = old_next_byte;
			inbuf->bytes_left = old_bytes_left;
			return PNM_SUSPEND;
		}
		break;
	default:
		break;
	}

368
	return PNM_OK;
369 370
}

371

372
static gint
373
pnm_read_raw_scanline (PnmLoaderContext *context)
374 375
{
	guint  numpix;
376
	guint  numbytes, offset;
377 378 379 380 381 382 383 384
	PnmIOBuffer *inbuf;

	g_return_val_if_fail (context != NULL, PNM_FATAL_ERR);

	inbuf = &context->inbuf;

	switch (context->type) {
	case PNM_FORMAT_PBM_RAW:
385 386
		numpix = inbuf->bytes_left * 8;
		break;
387
	case PNM_FORMAT_PGM_RAW:
388 389
		numpix = inbuf->bytes_left;
		break;
390
	case PNM_FORMAT_PPM_RAW:
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
		numpix = inbuf->bytes_left/3;
		break;
	default:
		g_warning ("io-pnm.c: Illegal raw pnm type!\n");
		return PNM_FATAL_ERR;
		break;
	}
	
	numpix = MIN (numpix, context->width - context->output_col);
	
	if (numpix == 0)
		return PNM_SUSPEND;
	
	context->dptr = context->pixels + 
		context->output_row * context->width * 3;
	
	switch (context->type) {
	case PNM_FORMAT_PBM_RAW:
		numbytes = numpix/8;
		offset = context->output_col/8;
		break;
	case PNM_FORMAT_PGM_RAW:
		numbytes = numpix;
		offset = context->output_col;
		break;
	case PNM_FORMAT_PPM_RAW:
		numbytes = numpix*3;
		offset = context->output_col*3;
		break;
	default:
		g_warning ("io-pnm.c: Illegal raw pnm type!\n");
		break;
	}
	
	memcpy (context->dptr + offset,	inbuf->next_byte, numbytes);
	
	inbuf->next_byte  += numbytes;
	inbuf->bytes_left -= numbytes;
	
	context->output_col += numpix;
	if (context->output_col == context->width) {
		if ( context->type == PNM_FORMAT_PBM_RAW )
			explode_bitmap_into_buf(context);
		else if ( context->type == PNM_FORMAT_PGM_RAW )
			explode_gray_into_buf (context);
		
		context->output_col = 0;
		context->output_row++;
		
	} else {
		return PNM_SUSPEND;
	}

	return PNM_OK;
}

447

448 449 450
static gint
pnm_read_ascii_scanline (PnmLoaderContext *context)
{
451
	guint  offset;
452 453 454 455 456 457 458 459 460 461 462
	gint   rc;
	guint  value, numval, i;
	guchar data;
	guchar mask;
	guchar *old_next_byte, *dptr;
	guint  old_bytes_left;
	PnmIOBuffer *inbuf;

	g_return_val_if_fail (context != NULL, PNM_FATAL_ERR);

	inbuf = &context->inbuf;
463

464 465 466 467 468 469
	context->dptr = context->pixels + 
		context->output_row * context->width * 3;

	switch (context->type) {
	case PNM_FORMAT_PBM:
		numval = 8;
470
		offset = context->output_col/8;
471 472 473
		break;
	case PNM_FORMAT_PGM:
		numval = 1;
474
		offset = context->output_col;
475 476 477
		break;
	case PNM_FORMAT_PPM:
		numval = 3;
478
		offset = context->output_col*3;
479 480 481 482 483 484 485
		break;
		
	default:
		g_warning ("Can't happen\n");
		return PNM_FATAL_ERR;
	}

486
	dptr = context->dptr + offset;
487

488 489 490 491
	while (TRUE) {
		if (context->type == PNM_FORMAT_PBM) {
			mask = 0x80;
			data = 0;
492
		}
493 494 495 496 497 498 499 500 501 502 503 504 505 506 507

		old_next_byte  = inbuf->next_byte;
		old_bytes_left = inbuf->bytes_left;
		
		for (i=0; i<numval; i++) {
			if ((rc = read_next_number (inbuf, &value))) {
				inbuf->next_byte  = old_next_byte;
				inbuf->bytes_left = old_bytes_left;
				return PNM_SUSPEND;
			}
			switch (context->type) {
			case PNM_FORMAT_PBM:
				if (value)
					data |= mask;
				mask >>= 1;
508
				
509 510 511 512 513 514 515 516 517 518 519
				break;
			case PNM_FORMAT_PGM:
				*dptr++ = (guchar)(255.0*((double)value/(double)context->maxval));
				break;
			case PNM_FORMAT_PPM:
				*dptr++ = (guchar)(255.0*((double)value/(double)context->maxval));
				break;
			default:
				g_warning ("io-pnm.c: Illegal raw pnm type!\n");
				break;
			}
520
		}
521
		
522 523
		if (context->type == PNM_FORMAT_PBM)
			*dptr++ = value;
524
		
525 526 527 528 529 530 531 532 533 534 535 536
		context->output_col++;
		if (context->output_col == context->width) {
			if ( context->type == PNM_FORMAT_PBM )
				explode_bitmap_into_buf(context);
			else if ( context->type == PNM_FORMAT_PGM )
				explode_gray_into_buf (context);

			context->output_col = 0;
			context->output_row++;
			break;
		}

537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568
	}

	return PNM_OK;
}

/* returns 1 if a scanline was converted,  0 means we ran out of data */
static gint
pnm_read_scanline (PnmLoaderContext *context)
{
	gint   rc;

	g_return_val_if_fail (context != NULL, PNM_FATAL_ERR);

	/* read in image data */
	/* for raw formats this is trivial */
	switch (context->type) {
	case PNM_FORMAT_PBM_RAW:
	case PNM_FORMAT_PGM_RAW:
	case PNM_FORMAT_PPM_RAW:
		rc = pnm_read_raw_scanline (context);
		if (rc == PNM_SUSPEND)
			return rc;
		break;

	case PNM_FORMAT_PBM:
	case PNM_FORMAT_PGM:
	case PNM_FORMAT_PPM:
		rc = pnm_read_ascii_scanline (context);
		if (rc == PNM_SUSPEND)
			return rc;
		break;

569 570 571 572
	default:
		g_print ("Cannot load these image types (yet)\n");
		return PNM_FATAL_ERR;
	}
573 574

	return PNM_OK;
575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602
}

/* Shared library entry point */
GdkPixbuf *
image_load (FILE *f)
{
	guint  nbytes;
	gint   rc;

	PnmLoaderContext context;
	PnmIOBuffer *inbuf;

	/* pretend to be doing progressive loading */
	context.updated_func = context.prepared_func = NULL;
	context.user_data = NULL;
	context.inbuf.bytes_left = 0;
	context.inbuf.next_byte  = NULL;
	context.pixels = context.pixbuf = NULL;
	context.got_header = context.did_prescan = FALSE;

	inbuf = &context.inbuf;

	while (TRUE) {
		guint  num_to_read;

		/* keep buffer as full as possible */
		num_to_read = PNM_BUF_SIZE - inbuf->bytes_left;

603
		if (inbuf->next_byte != NULL && inbuf->bytes_left > 0)
604 605 606
			memmove (inbuf->buffer, inbuf->next_byte, 
				 inbuf->bytes_left);

607 608
		nbytes = fread (inbuf->buffer+inbuf->bytes_left, 
				1, num_to_read, f);
609 610 611 612 613 614
		inbuf->bytes_left += nbytes;
		inbuf->next_byte   = inbuf->buffer;
		
		/* ran out of data and we haven't exited main loop */
		/* something is wrong                              */
		if (inbuf->bytes_left == 0) {
615 616
			if (context.pixbuf)
				gdk_pixbuf_unref (context.pixbuf);
617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641
			g_warning ("io-pnm.c: Ran out of data...\n");
			return NULL;
		}

		/* get header if needed */
		if (!context.got_header) {
		
			rc = pnm_read_header (&context);
			if (rc == PNM_FATAL_ERR)
				return NULL;
			else if (rc == PNM_SUSPEND)
				continue;

			context.got_header = TRUE;
		}

		/* scan until we hit image data */
		if (!context.did_prescan) {
			if (skip_ahead_whitespace (inbuf) == NULL)
				continue;

			context.did_prescan = TRUE;
			context.output_row = 0;
			context.output_col = 0;

642
			context.pixels = g_malloc (context.height * 
643
					   context.width * 3);
644 645 646 647 648 649 650 651 652 653 654 655 656 657

			context.pixbuf = gdk_pixbuf_new(ART_PIX_RGB, 
							 /*have_alpha*/ FALSE,
							 8, 
							 context.width,
							 context.height);


			if (context.pixbuf == NULL) {
				/* Failed to allocate memory */
				g_error ("Couldn't allocate gdkpixbuf");
			}

			context.pixels = context.pixbuf->art_pixbuf->pixels;
658 659 660 661 662 663 664 665 666
		}

		/* if we got here we're reading image data */
		while (context.output_row < context.height) {
			rc = pnm_read_scanline (&context);

			if (rc == PNM_SUSPEND) {
				break;
			} else if (rc == PNM_FATAL_ERR) {
667 668
				if (context.pixbuf)
					gdk_pixbuf_unref (context.pixbuf);
669 670 671 672 673 674 675 676 677 678 679
				g_warning ("io-pnm.c: error reading rows..\n");
				return NULL;
			}
		}

		if (context.output_row < context.height)
			continue;
		else
			break;
	}

680 681 682
	return gdk_pixbuf_new_from_data (context.pixels, ART_PIX_RGB, FALSE,
					 context.width, context.height, 
					 context.width * 3, free_buffer, NULL);
683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731

}

#if 0
/**** Progressive image loading handling *****/

/* these routines required because we are acting as a source manager for */
/* libjpeg. */
static void
init_source (j_decompress_ptr cinfo)
{
	my_src_ptr src = (my_src_ptr) cinfo->src;

	src->skip_next = 0;
}


static void
term_source (j_decompress_ptr cinfo)
{
	/* XXXX - probably should scream something has happened */
}


/* for progressive loading (called "I/O Suspension" by libjpeg docs) */
/* we do nothing except return "FALSE"                               */
static boolean
fill_input_buffer (j_decompress_ptr cinfo)
{
	return FALSE;
}


static void
skip_input_data (j_decompress_ptr cinfo, long num_bytes)
{
	my_src_ptr src = (my_src_ptr) cinfo->src;
	long   num_can_do;

	/* move as far as we can into current buffer */
	/* then set skip_next to catch the rest      */
	if (num_bytes > 0) {
		num_can_do = MIN (src->pub.bytes_in_buffer, num_bytes);
		src->pub.next_input_byte += (size_t) num_can_do;
		src->pub.bytes_in_buffer -= (size_t) num_can_do;

		src->skip_next = num_bytes - num_can_do;
	}
}
732
#endif
733

734
#if 0 
735 736 737 738 739 740 741 742 743 744 745
/* 
 * func - called when we have pixmap created (but no image data)
 * user_data - passed as arg 1 to func
 * return context (opaque to user)
 */

gpointer
image_begin_load (ModulePreparedNotifyFunc prepared_func, 
		  ModuleUpdatedNotifyFunc  updated_func,
		  gpointer user_data)
{
746
	PnmLoaderContext *context;
747 748 749 750 751

	context = g_new0 (JpegProgContext, 1);
	context->prepared_func = prepared_func;
	context->updated_func  = updated_func;
	context->user_data = user_data;
752
	context->pixbuf = context->pixels = NULL;
753 754 755
	context->got_header = FALSE;
	context->did_prescan = FALSE;

756 757
	context->inbuf.bytes_left = 0;
	context->inbuf.next_byte  = NULL;
758 759 760 761 762 763 764 765 766 767 768 769

	return (gpointer) context;
}

/*
 * context - returned from image_begin_load
 *
 * free context, unref gdk_pixbuf
 */
void
image_stop_load (gpointer data)
{
770
	PnmLoaderContext *context = (PnmLoaderContext *) data;
771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986

	g_return_if_fail (context != NULL);

	if (context->pixbuf)
		gdk_pixbuf_unref (context->pixbuf);

	g_free (context);
}




/*
 * context - from image_begin_load
 * buf - new image data
 * size - length of new image data
 *
 * append image data onto inrecrementally built output image
 */
gboolean
image_load_increment (gpointer data, guchar *buf, guint size)
{
	JpegProgContext *context = (JpegProgContext *)data;
	struct jpeg_decompress_struct *cinfo;
	my_src_ptr  src;
	guint       num_left, num_copy;
	guint       last_bytes_left;
	guint       spinguard;
	guchar *bufhd;

	g_return_val_if_fail (context != NULL, FALSE);
	g_return_val_if_fail (buf != NULL, FALSE);

	src = (my_src_ptr) context->cinfo.src;

	cinfo = &context->cinfo;

	/* XXXXXXX (drmike) - loop(s) below need to be recoded now I
         *                    have a grasp of what the flow needs to be!
         */


	/* skip over data if requested, handle unsigned int sizes cleanly */
	/* only can happen if we've already called jpeg_get_header once   */
	if (context->src_initialized && src->skip_next) {
		if (src->skip_next > size) {
			src->skip_next -= size;
			return TRUE;
		} else {
			num_left = size - src->skip_next;
			bufhd = buf + src->skip_next;
			src->skip_next = 0;
		}
	} else {
		num_left = size;
		bufhd = buf;
	}


	last_bytes_left = 0;
	spinguard = 0;
	while (src->pub.bytes_in_buffer != 0 || num_left != 0) {

		/* handle any data from caller we haven't processed yet */
		if (num_left > 0) {
			if(src->pub.bytes_in_buffer && 
			   src->pub.next_input_byte != src->buffer)
				memmove(src->buffer, src->pub.next_input_byte,
					src->pub.bytes_in_buffer);


			num_copy = MIN (JPEG_PROG_BUF_SIZE - src->pub.bytes_in_buffer,
					num_left);

/*			if (num_copy == 0) 
				g_error ("Buffer overflow!");
*/
			memcpy(src->buffer + src->pub.bytes_in_buffer, bufhd,num_copy);
			src->pub.next_input_byte = src->buffer;
			src->pub.bytes_in_buffer += num_copy;
			bufhd += num_copy;
			num_left -= num_copy;
		} else {
		/* did anything change from last pass, if not return */
			if (last_bytes_left == 0)
				last_bytes_left = src->pub.bytes_in_buffer;
			else if (src->pub.bytes_in_buffer == last_bytes_left)
				spinguard++;
			else
				last_bytes_left = src->pub.bytes_in_buffer;
		}

		/* should not go through twice and not pull bytes out of buf */
		if (spinguard > 2)
			return TRUE;

		/* try to load jpeg header */
		if (!context->got_header) {
			int rc;

			rc = jpeg_read_header (cinfo, TRUE);
			context->src_initialized = TRUE;

			if (rc == JPEG_SUSPENDED)
				continue;

			context->got_header = TRUE;

			if (jpeg_has_multiple_scans (cinfo)) {
				g_print ("io-jpeg.c: Does not currently "
					 "support progressive jpeg files.\n");
				return FALSE;
			}

			context->pixbuf = gdk_pixbuf_new(ART_PIX_RGB, 
							 /*have_alpha*/ FALSE,
							 8, 
							 cinfo->image_width,
							 cinfo->image_height);

			if (context->pixbuf == NULL) {
				/* Failed to allocate memory */
				g_error ("Couldn't allocate gdkpixbuf");
			}

			/* Use pixbuf buffer to store decompressed data */
			context->dptr = context->pixbuf->art_pixbuf->pixels;

			/* Notify the client that we are ready to go */
			(* context->prepared_func) (context->pixbuf,
						    context->user_data);

		} else if (!context->did_prescan) {
			int rc;

			/* start decompression */
			rc = jpeg_start_decompress (cinfo);
			cinfo->do_fancy_upsampling = FALSE;
			cinfo->do_block_smoothing = FALSE;

			if (rc == JPEG_SUSPENDED)
				continue;

			context->did_prescan = TRUE;
		} else {
			/* we're decompressing so feed jpeg lib scanlines */
			guchar *lines[4];
			guchar **lptr;
			guchar *rowptr, *p;
			gint   nlines, i;
			gint   start_scanline;

			/* keep going until we've done all scanlines */
			while (cinfo->output_scanline < cinfo->output_height) {
				start_scanline = cinfo->output_scanline;
				lptr = lines;
				rowptr = context->dptr;
				for (i=0; i < cinfo->rec_outbuf_height; i++) {
					*lptr++ = rowptr;
					rowptr += context->pixbuf->art_pixbuf->rowstride;;
				}

#ifdef IO_JPEG_DEBUG_GREY
				for (p=lines[0],i=0; i< context->pixbuf->art_pixbuf->rowstride;i++, p++)
					*p = 0;
				
#endif
				nlines = jpeg_read_scanlines (cinfo, lines,
							      cinfo->rec_outbuf_height);
				if (nlines == 0)
					break;

				/* handle gray */
				if (cinfo->output_components == 1)
					explode_gray_into_buf (cinfo, lines);

				context->dptr += nlines * context->pixbuf->art_pixbuf->rowstride;

				/* send updated signal */
				(* context->updated_func) (context->pixbuf,
						 context->user_data,
						 0, 
						 cinfo->output_scanline-1,
						 cinfo->image_width, 
						 nlines);

#undef DEBUG_JPEG_PROGRESSIVE
#ifdef DEBUG_JPEG_PROGRESSIVE
				
				if (start_scanline != cinfo->output_scanline)
					g_print("jpeg: Input pass=%2d, next input scanline=%3d,"
						" emitted %3d - %3d\n",
						cinfo->input_scan_number, cinfo->input_iMCU_row * 16,
						start_scanline, cinfo->output_scanline - 1);
				
				
				
				g_print ("Scanline %d of %d - ", 
					 cinfo->output_scanline,
					 cinfo->output_height);
/*			g_print ("rec_height %d -", cinfo->rec_outbuf_height); */
				g_print ("Processed %d lines - bytes left = %d\n",
					 nlines, cinfo->src->bytes_in_buffer);
#endif
			}
			/* did entire image */
			if (cinfo->output_scanline >= cinfo->output_height)
				return TRUE;
			else
				continue;
		}
	}

	return TRUE;
}
#endif