summaryrefslogtreecommitdiff
path: root/indra/llimage/llimagejpeg.cpp
blob: e419c77ff2ce4b1f8f84ba8999844a2378b17c3b (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
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
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
569
570
571
572
573
574
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
603
604
605
606
607
608
609
610
611
612
613
614
615
616
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
642
643
644
645
646
647
648
649
650
651
652
653
654
/** 
 * @file llimagejpeg.cpp
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"
#include "stdtypes.h"

#include "llimagejpeg.h"

#include "llerror.h"

jmp_buf	LLImageJPEG::sSetjmpBuffer ;
LLImageJPEG::LLImageJPEG(S32 quality) 
:	LLImageFormatted(IMG_CODEC_JPEG),
	mOutputBuffer( NULL ),
	mOutputBufferSize( 0 ),
	mEncodeQuality( quality ) // on a scale from 1 to 100
{
}

LLImageJPEG::~LLImageJPEG()
{
	llassert( !mOutputBuffer ); // Should already be deleted at end of encode.
	delete[] mOutputBuffer;
}

BOOL LLImageJPEG::updateData()
{
	resetLastError();

	// Check to make sure that this instance has been initialized with data
	if (!getData() || (0 == getDataSize()))
	{
		setLastError("Uninitialized instance of LLImageJPEG");
		return FALSE;
	}

	////////////////////////////////////////
	// Step 1: allocate and initialize JPEG decompression object

	// This struct contains the JPEG decompression parameters and pointers to
	// working space (which is allocated as needed by the JPEG library).
	struct jpeg_decompress_struct cinfo;
	cinfo.client_data = this;

	struct jpeg_error_mgr jerr;
	cinfo.err = jpeg_std_error(&jerr);
	
	// Customize with our own callbacks
	jerr.error_exit =		&LLImageJPEG::errorExit;			// Error exit handler: does not return to caller
	jerr.emit_message =		&LLImageJPEG::errorEmitMessage;		// Conditionally emit a trace or warning message
	jerr.output_message =	&LLImageJPEG::errorOutputMessage;	// Routine that actually outputs a trace or error message
	
	//
	//try/catch will crash on Mac and Linux if LLImageJPEG::errorExit throws an error
	//so as instead, we use setjmp/longjmp to avoid this crash, which is the best we can get. --bao 
	//
	if(setjmp(sSetjmpBuffer))
	{
		jpeg_destroy_decompress(&cinfo);
		return FALSE;
	}
	try
	{
		// Now we can initialize the JPEG decompression object.
		jpeg_create_decompress(&cinfo);

		////////////////////////////////////////
		// Step 2: specify data source
		// (Code is modified version of jpeg_stdio_src();
		if (cinfo.src == NULL)
		{	
			cinfo.src = (struct jpeg_source_mgr *)
				(*cinfo.mem->alloc_small) ((j_common_ptr) &cinfo, JPOOL_PERMANENT,
				sizeof(struct jpeg_source_mgr));
		}
		cinfo.src->init_source	=		&LLImageJPEG::decodeInitSource;
		cinfo.src->fill_input_buffer =	&LLImageJPEG::decodeFillInputBuffer;
		cinfo.src->skip_input_data =	&LLImageJPEG::decodeSkipInputData;
		cinfo.src->resync_to_restart = jpeg_resync_to_restart; // For now, use default method, but we should be able to do better.
		cinfo.src->term_source =		&LLImageJPEG::decodeTermSource;

		cinfo.src->bytes_in_buffer =	getDataSize();
		cinfo.src->next_input_byte =	getData();
		
		////////////////////////////////////////
		// Step 3: read file parameters with jpeg_read_header()
		jpeg_read_header( &cinfo, TRUE );

		// Data set by jpeg_read_header
		setSize(cinfo.image_width, cinfo.image_height, 3); // Force to 3 components (RGB)

		/*
		// More data set by jpeg_read_header
		cinfo.num_components;
		cinfo.jpeg_color_space;	// Colorspace of image
		cinfo.saw_JFIF_marker;		// TRUE if a JFIF APP0 marker was seen
		cinfo.JFIF_major_version;	// Version information from JFIF marker
		cinfo.JFIF_minor_version;  //
		cinfo.density_unit;		// Resolution data from JFIF marker
		cinfo.X_density;
		cinfo.Y_density;
		cinfo.saw_Adobe_marker;	// TRUE if an Adobe APP14 marker was seen
		cinfo.Adobe_transform;     // Color transform code from Adobe marker
		*/
	}
	catch (int)
	{
		jpeg_destroy_decompress(&cinfo);

		return FALSE;
	}
	////////////////////////////////////////
	// Step 4: Release JPEG decompression object 
	jpeg_destroy_decompress(&cinfo);

	return TRUE;
}

// Initialize source --- called by jpeg_read_header
// before any data is actually read.
void LLImageJPEG::decodeInitSource( j_decompress_ptr cinfo )
{
	// no work necessary here
}

// Fill the input buffer --- called whenever buffer is emptied.
boolean LLImageJPEG::decodeFillInputBuffer( j_decompress_ptr cinfo )
{
//	jpeg_source_mgr* src = cinfo->src;
//	LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;

	// Should never get here, since we provide the entire buffer up front.
	ERREXIT(cinfo, JERR_INPUT_EMPTY);

	return TRUE;
}

// Skip data --- used to skip over a potentially large amount of
// uninteresting data (such as an APPn marker).
//
// Writers of suspendable-input applications must note that skip_input_data
// is not granted the right to give a suspension return.  If the skip extends
// beyond the data currently in the buffer, the buffer can be marked empty so
// that the next read will cause a fill_input_buffer call that can suspend.
// Arranging for additional bytes to be discarded before reloading the input
// buffer is the application writer's problem.
void LLImageJPEG::decodeSkipInputData (j_decompress_ptr cinfo, long num_bytes)
{
	jpeg_source_mgr* src = cinfo->src;
//	LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;

    src->next_input_byte += (size_t) num_bytes;
    src->bytes_in_buffer -= (size_t) num_bytes;
}

void LLImageJPEG::decodeTermSource (j_decompress_ptr cinfo)
{
  // no work necessary here
}


// Returns true when done, whether or not decode was successful.
BOOL LLImageJPEG::decode(LLImageRaw* raw_image, F32 decode_time)
{
	llassert_always(raw_image);
	
	resetLastError();
	
	// Check to make sure that this instance has been initialized with data
	if (!getData() || (0 == getDataSize()))
	{
		setLastError("LLImageJPEG trying to decode an image with no data!");
		return TRUE;  // done
	}
	
	S32 row_stride = 0;
	U8* raw_image_data = NULL;

	////////////////////////////////////////
	// Step 1: allocate and initialize JPEG decompression object

	// This struct contains the JPEG decompression parameters and pointers to
	// working space (which is allocated as needed by the JPEG library).
	struct jpeg_decompress_struct cinfo;

	struct jpeg_error_mgr jerr;
	cinfo.err = jpeg_std_error(&jerr);
	
	// Customize with our own callbacks
	jerr.error_exit =		&LLImageJPEG::errorExit;			// Error exit handler: does not return to caller
	jerr.emit_message =		&LLImageJPEG::errorEmitMessage;		// Conditionally emit a trace or warning message
	jerr.output_message =	&LLImageJPEG::errorOutputMessage;	// Routine that actually outputs a trace or error message
	
	//
	//try/catch will crash on Mac and Linux if LLImageJPEG::errorExit throws an error
	//so as instead, we use setjmp/longjmp to avoid this crash, which is the best we can get. --bao 
	//
	if(setjmp(sSetjmpBuffer))
	{
		jpeg_destroy_decompress(&cinfo);
		return TRUE; // done
	}
	try
	{
		// Now we can initialize the JPEG decompression object.
		jpeg_create_decompress(&cinfo);

		////////////////////////////////////////
		// Step 2: specify data source
		// (Code is modified version of jpeg_stdio_src();
		if (cinfo.src == NULL)
		{	
			cinfo.src = (struct jpeg_source_mgr *)
				(*cinfo.mem->alloc_small) ((j_common_ptr) &cinfo, JPOOL_PERMANENT,
				sizeof(struct jpeg_source_mgr));
		}
		cinfo.src->init_source	=		&LLImageJPEG::decodeInitSource;
		cinfo.src->fill_input_buffer =	&LLImageJPEG::decodeFillInputBuffer;
		cinfo.src->skip_input_data =	&LLImageJPEG::decodeSkipInputData;
		cinfo.src->resync_to_restart = jpeg_resync_to_restart; // For now, use default method, but we should be able to do better.
		cinfo.src->term_source =		&LLImageJPEG::decodeTermSource;
		cinfo.src->bytes_in_buffer =	getDataSize();
		cinfo.src->next_input_byte =	getData();
		
		////////////////////////////////////////
		// Step 3: read file parameters with jpeg_read_header()
		
		jpeg_read_header(&cinfo, TRUE);

		// We can ignore the return value from jpeg_read_header since
		//   (a) suspension is not possible with our data source, and
		//   (b) we passed TRUE to reject a tables-only JPEG file as an error.
		// See libjpeg.doc for more info.

		setSize(cinfo.image_width, cinfo.image_height, 3); // Force to 3 components (RGB)

		raw_image->resize(getWidth(), getHeight(), getComponents());
		raw_image_data = raw_image->getData();
		
		
		////////////////////////////////////////
		// Step 4: set parameters for decompression 
		cinfo.out_color_components = 3;
		cinfo.out_color_space = JCS_RGB;
   

		////////////////////////////////////////
		// Step 5: Start decompressor 
		
		jpeg_start_decompress(&cinfo);
		// We can ignore the return value since suspension is not possible
		// with our data source.
		
		// We may need to do some setup of our own at this point before reading
		// the data.  After jpeg_start_decompress() we have the correct scaled
		// output image dimensions available, as well as the output colormap
		// if we asked for color quantization.
		// In this example, we need to make an output work buffer of the right size.
    
		// JSAMPLEs per row in output buffer 
		row_stride = cinfo.output_width * cinfo.output_components;
		
		////////////////////////////////////////
		// Step 6: while (scan lines remain to be read) 
		//           jpeg_read_scanlines(...); 
		
		// Here we use the library's state variable cinfo.output_scanline as the
		// loop counter, so that we don't have to keep track ourselves.
		
		// Move pointer to last line
		raw_image_data += row_stride * (cinfo.output_height - 1);

		while (cinfo.output_scanline < cinfo.output_height)
		{
			// jpeg_read_scanlines expects an array of pointers to scanlines.
			// Here the array is only one element long, but you could ask for
			// more than one scanline at a time if that's more convenient.
			
			jpeg_read_scanlines(&cinfo, &raw_image_data, 1);
			raw_image_data -= row_stride;  // move pointer up a line
		}

		////////////////////////////////////////
		// Step 7: Finish decompression 
		jpeg_finish_decompress(&cinfo);

		////////////////////////////////////////
		// Step 8: Release JPEG decompression object 
		jpeg_destroy_decompress(&cinfo);
	}

	catch (int)
	{
		jpeg_destroy_decompress(&cinfo);
		return TRUE; // done
	}

	// Check to see whether any corrupt-data warnings occurred
	if( jerr.num_warnings != 0 )
	{
		// TODO: extract the warning to find out what went wrong.
		setLastError( "Unable to decode JPEG image.");
		return TRUE; // done
	}

	return TRUE;
}


// Initialize destination --- called by jpeg_start_compress before any data is actually written.
// static
void LLImageJPEG::encodeInitDestination ( j_compress_ptr cinfo )
{
  LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;

  cinfo->dest->next_output_byte = self->mOutputBuffer;
  cinfo->dest->free_in_buffer = self->mOutputBufferSize;
}


//  Empty the output buffer --- called whenever buffer fills up.
// 
//  In typical applications, this should write the entire output buffer
//  (ignoring the current state of next_output_byte & free_in_buffer),
//  reset the pointer & count to the start of the buffer, and return TRUE
//  indicating that the buffer has been dumped.
// 
//  In applications that need to be able to suspend compression due to output
//  overrun, a FALSE return indicates that the buffer cannot be emptied now.
//  In this situation, the compressor will return to its caller (possibly with
//  an indication that it has not accepted all the supplied scanlines).  The
//  application should resume compression after it has made more room in the
//  output buffer.  Note that there are substantial restrictions on the use of
//  suspension --- see the documentation.
// 
//  When suspending, the compressor will back up to a convenient restart point
//  (typically the start of the current MCU). next_output_byte & free_in_buffer
//  indicate where the restart point will be if the current call returns FALSE.
//  Data beyond this point will be regenerated after resumption, so do not
//  write it out when emptying the buffer externally.

boolean LLImageJPEG::encodeEmptyOutputBuffer( j_compress_ptr cinfo )
{
  LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;

  // Should very rarely happen, since our output buffer is
  // as large as the input to start out with.
  
  // Double the buffer size;
  S32 new_buffer_size = self->mOutputBufferSize * 2;
  U8* new_buffer = new U8[ new_buffer_size ];
  if (!new_buffer)
  {
  	LL_ERRS() << "Out of memory in LLImageJPEG::encodeEmptyOutputBuffer( j_compress_ptr cinfo )" << LL_ENDL;
  	return FALSE;
  }
  memcpy( new_buffer, self->mOutputBuffer, self->mOutputBufferSize );	/* Flawfinder: ignore */
  delete[] self->mOutputBuffer;
  self->mOutputBuffer = new_buffer;

  cinfo->dest->next_output_byte = self->mOutputBuffer + self->mOutputBufferSize;
  cinfo->dest->free_in_buffer = self->mOutputBufferSize;
  self->disclaimMem(self->mOutputBufferSize);
  self->mOutputBufferSize = new_buffer_size;
  self->claimMem(new_buffer_size);

  return TRUE;
}

//  Terminate destination --- called by jpeg_finish_compress
//  after all data has been written.  Usually needs to flush buffer.
// 
//  NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
//  application must deal with any cleanup that should happen even
//  for error exit.
void LLImageJPEG::encodeTermDestination( j_compress_ptr cinfo )
{
	LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;

	S32 file_bytes = (S32)(self->mOutputBufferSize - cinfo->dest->free_in_buffer);
	self->allocateData(file_bytes);

	memcpy( self->getData(), self->mOutputBuffer, file_bytes );	/* Flawfinder: ignore */
}

// static 
void LLImageJPEG::errorExit( j_common_ptr cinfo )	
{
	//LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;

	// Always display the message
	(*cinfo->err->output_message)(cinfo);

	// Let the memory manager delete any temp files
	jpeg_destroy(cinfo);

	// Return control to the setjmp point
	longjmp(sSetjmpBuffer, 1) ;
}

// Decide whether to emit a trace or warning message.
// msg_level is one of:
//   -1: recoverable corrupt-data warning, may want to abort.
//    0: important advisory messages (always display to user).
//    1: first level of tracing detail.
//    2,3,...: successively more detailed tracing messages.
// An application might override this method if it wanted to abort on warnings
// or change the policy about which messages to display.
// static 
void LLImageJPEG::errorEmitMessage( j_common_ptr cinfo, int msg_level )
{
  struct jpeg_error_mgr * err = cinfo->err;

  if (msg_level < 0) 
  {
	  // It's a warning message.  Since corrupt files may generate many warnings,
	  // the policy implemented here is to show only the first warning,
	  // unless trace_level >= 3.
	  if (err->num_warnings == 0 || err->trace_level >= 3)
	  {
		  (*err->output_message) (cinfo);
	  }
	  // Always count warnings in num_warnings.
	  err->num_warnings++;
  }
  else 
  {
	  // It's a trace message.  Show it if trace_level >= msg_level.
	  if (err->trace_level >= msg_level)
	  {
		  (*err->output_message) (cinfo);
	  }
  }
}

// static 
void LLImageJPEG::errorOutputMessage( j_common_ptr cinfo )
{
	// Create the message
	char buffer[JMSG_LENGTH_MAX];	/* Flawfinder: ignore */
	(*cinfo->err->format_message) (cinfo, buffer);

	std::string error = buffer ;
	LLImage::setLastError(error);

	BOOL is_decode = (cinfo->is_decompressor != 0);
	LL_WARNS() << "LLImageJPEG " << (is_decode ? "decode " : "encode ") << " failed: " << buffer << LL_ENDL;
}

BOOL LLImageJPEG::encode( const LLImageRaw* raw_image, F32 encode_time )
{
	llassert_always(raw_image);
	
	resetLastError();

	switch( raw_image->getComponents() )
	{
	case 1:
	case 3:
		break;
	default:
		setLastError("Unable to encode a JPEG image that doesn't have 1 or 3 components.");
		return FALSE;
	}

	setSize(raw_image->getWidth(), raw_image->getHeight(), raw_image->getComponents());

	// Allocate a temporary buffer big enough to hold the entire compressed image (and then some)
	// (Note: we make it bigger in emptyOutputBuffer() if we need to)
	delete[] mOutputBuffer;
	disclaimMem(mOutputBufferSize);
	mOutputBufferSize = getWidth() * getHeight() * getComponents() + 1024;
	claimMem(mOutputBufferSize);
	mOutputBuffer = new U8[ mOutputBufferSize ];

	const U8* raw_image_data = NULL;
	S32 row_stride = 0;

	////////////////////////////////////////
	// Step 1: allocate and initialize JPEG compression object

	// This struct contains the JPEG compression parameters and pointers to
	// working space (which is allocated as needed by the JPEG library).
	struct jpeg_compress_struct cinfo;
	cinfo.client_data = this;

	// We have to set up the error handler first, in case the initialization
	// step fails.  (Unlikely, but it could happen if you are out of memory.)
	// This routine fills in the contents of struct jerr, and returns jerr's
	// address which we place into the link field in cinfo.
	struct jpeg_error_mgr jerr;
	cinfo.err = jpeg_std_error(&jerr);

	// Customize with our own callbacks
	jerr.error_exit =		&LLImageJPEG::errorExit;			// Error exit handler: does not return to caller
	jerr.emit_message =		&LLImageJPEG::errorEmitMessage;		// Conditionally emit a trace or warning message
	jerr.output_message =	&LLImageJPEG::errorOutputMessage;	// Routine that actually outputs a trace or error message

	//
	//try/catch will crash on Mac and Linux if LLImageJPEG::errorExit throws an error
	//so as instead, we use setjmp/longjmp to avoid this crash, which is the best we can get. --bao 
	//
	if( setjmp(sSetjmpBuffer) ) 
	{
		// If we get here, the JPEG code has signaled an error.
		// We need to clean up the JPEG object, close the input file, and return.
		jpeg_destroy_compress(&cinfo);
		delete[] mOutputBuffer;
		mOutputBuffer = NULL;
		disclaimMem(mOutputBufferSize);
		mOutputBufferSize = 0;
		return FALSE;
	}

	try
	{

		// Now we can initialize the JPEG compression object.
		jpeg_create_compress(&cinfo);

		////////////////////////////////////////
		// Step 2: specify data destination
		// (code is a modified form of jpeg_stdio_dest() )
		if( cinfo.dest == NULL)
		{	
			cinfo.dest = (struct jpeg_destination_mgr *)
				(*cinfo.mem->alloc_small) ((j_common_ptr) &cinfo, JPOOL_PERMANENT,
				sizeof(struct jpeg_destination_mgr));
		}
		cinfo.dest->next_output_byte =		mOutputBuffer;		// => next byte to write in buffer
		cinfo.dest->free_in_buffer =		mOutputBufferSize;	// # of byte spaces remaining in buffer
		cinfo.dest->init_destination =		&LLImageJPEG::encodeInitDestination;
		cinfo.dest->empty_output_buffer =	&LLImageJPEG::encodeEmptyOutputBuffer;
		cinfo.dest->term_destination =		&LLImageJPEG::encodeTermDestination;

		////////////////////////////////////////
		// Step 3: set parameters for compression 
		//
		// First we supply a description of the input image.
		// Four fields of the cinfo struct must be filled in:
		
		cinfo.image_width = getWidth(); 	// image width and height, in pixels 
		cinfo.image_height = getHeight();

		switch( getComponents() )
		{
		case 1:
			cinfo.input_components = 1;		// # of color components per pixel
			cinfo.in_color_space = JCS_GRAYSCALE; // colorspace of input image
			break;
		case 3:
			cinfo.input_components = 3;		// # of color components per pixel
			cinfo.in_color_space = JCS_RGB; // colorspace of input image
			break;
		default:
			setLastError("Unable to encode a JPEG image that doesn't have 1 or 3 components.");
			return FALSE;
		}

		// Now use the library's routine to set default compression parameters.
		// (You must set at least cinfo.in_color_space before calling this,
		// since the defaults depend on the source color space.)
		jpeg_set_defaults(&cinfo);

		// Now you can set any non-default parameters you wish to.
		jpeg_set_quality(&cinfo, mEncodeQuality, TRUE );  // limit to baseline-JPEG values

		////////////////////////////////////////
		// Step 4: Start compressor 
		//
		// TRUE ensures that we will write a complete interchange-JPEG file.
		// Pass TRUE unless you are very sure of what you're doing.
   
		jpeg_start_compress(&cinfo, TRUE);

		////////////////////////////////////////
		// Step 5: while (scan lines remain to be written) 
		//            jpeg_write_scanlines(...); 

		// Here we use the library's state variable cinfo.next_scanline as the
		// loop counter, so that we don't have to keep track ourselves.
		// To keep things simple, we pass one scanline per call; you can pass
		// more if you wish, though.
   
		row_stride = getWidth() * getComponents();	// JSAMPLEs per row in image_buffer

		// NOTE: For compatibility with LLImage, we need to invert the rows.
		raw_image_data = raw_image->getData();
		
		const U8* last_row_data = raw_image_data + (getHeight()-1) * row_stride;

		JSAMPROW row_pointer[1];				// pointer to JSAMPLE row[s]
		while (cinfo.next_scanline < cinfo.image_height) 
		{
			// jpeg_write_scanlines expects an array of pointers to scanlines.
			// Here the array is only one element long, but you could pass
			// more than one scanline at a time if that's more convenient.

			//Ugly const uncast here (jpeg_write_scanlines should take a const* but doesn't)
			//row_pointer[0] = (JSAMPROW)(raw_image_data + (cinfo.next_scanline * row_stride));
			row_pointer[0] = (JSAMPROW)(last_row_data - (cinfo.next_scanline * row_stride));

			jpeg_write_scanlines(&cinfo, row_pointer, 1);
		}

		////////////////////////////////////////
		//   Step 6: Finish compression 
		jpeg_finish_compress(&cinfo);

		// After finish_compress, we can release the temp output buffer. 
		delete[] mOutputBuffer;
		mOutputBuffer = NULL;
		disclaimMem(mOutputBufferSize);
		mOutputBufferSize = 0;

		////////////////////////////////////////
		//   Step 7: release JPEG compression object 
		jpeg_destroy_compress(&cinfo);
	}

	catch(int)
	{
		jpeg_destroy_compress(&cinfo);
		delete[] mOutputBuffer;
		mOutputBuffer = NULL;
		disclaimMem(mOutputBufferSize);
		mOutputBufferSize = 0;
		return FALSE;
	}

	return TRUE;
}