aboutsummaryrefslogtreecommitdiff
path: root/libcrystfel/src/reflist.c
blob: cea25bf3a9fcc9c33c325c36c5d716a158208352 (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
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
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
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
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
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
/*
 * reflist.c
 *
 * Fast reflection/peak list
 *
 * Copyright © 2012 Deutsches Elektronen-Synchrotron DESY,
 *                  a research centre of the Helmholtz Association.
 *
 * Authors:
 *   2011-2012 Thomas White <taw@physics.org>
 *
 * This file is part of CrystFEL.
 *
 * CrystFEL is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * CrystFEL 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with CrystFEL.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <pthread.h>

#include "reflist.h"
#include "utils.h"

/**
 * SECTION:reflist
 * @short_description: The fast reflection list
 * @title: RefList
 * @section_id:
 * @see_also:
 * @include: "reflist.h"
 * @Image:
 *
 * The fast reflection list stores reflections in an RB-tree indexed
 * by the Miller indices h, k and l.  Any reflection can be found in a
 * length of time which scales logarithmically with the number of reflections in
 * the list.
 *
 * A RefList can contain any number of reflections, and can store more than
 * one reflection with a given set of indices, for example when two distinct
 * reflections are to be stored according to their asymmetric indices.
 *
 * There are getters and setters which can be used to get and set values for an
 * individual reflection.  The reflection list does not calculate any values,
 * only stores what it was given earlier.  As such, you will need to carefully
 * examine which fields your prior processing steps have filled in.
 */


struct _refldata {

	/* Symmetric indices (i.e. the "real" indices) */
	signed int hs;
	signed int ks;
	signed int ls;

	/* Partiality and related geometrical stuff */
	double r1;  /* First excitation error */
	double r2;  /* Second excitation error */
	double p;   /* Partiality */
	int clamp1; /* Clamp status for r1 */
	int clamp2; /* Clamp status for r2 */

	/* Location in image */
	double fs;
	double ss;

	/* The distance from the exact Bragg position to the coordinates
	 * given above. */
	double excitation_error;

	/* Non-zero if this reflection can be used for scaling */
	int scalable;

	/* Non-zero if this reflection should be used as a "guide star" for
	 * post refinement */
	int refinable;

	/* Intensity */
	double intensity;
	double esd_i;

	/* Phase */
	double phase;
	int have_phase;

	/* Redundancy */
	int redundancy;

	/* User-specified temporary values */
	double temp1;
	double temp2;
};


enum _nodecol {
	RED,
	BLACK
};


struct _reflection {

	/* Listy stuff */
	unsigned int serial;          /* Unique serial number, key */
	struct _reflection *child[2]; /* Child nodes */
	struct _reflection *next;     /* Next and previous in doubly linked */
	struct _reflection *prev;     /*  list of duplicate reflections */
	enum _nodecol col;            /* Colour (red or black) */

	/* Payload */
	pthread_mutex_t lock;         /* Protects the contents of "data" */
	struct _refldata data;
};


struct _reflist {

	struct _reflection *head;
	struct _reflection *tail;

};


#define SERIAL(h, k, l) ((((h)+256)<<18) + (((k)+256)<<9) + ((l)+256))
#define GET_H(serial) ((((serial) & 0xfffc0000)>>18)-256)
#define GET_K(serial) ((((serial) & 0x0003fe00)>>9)-256)
#define GET_L(serial) (((serial) & 0x000001ff)-256)

/**************************** Creation / deletion *****************************/

static Reflection *new_node(unsigned int serial)
{
	Reflection *new;

	new = calloc(1, sizeof(struct _reflection));
	new->serial = serial;
	new->next = NULL;
	new->prev = NULL;
	new->child[0] = NULL;
	new->child[1] = NULL;
	new->col = RED;
	pthread_mutex_init(&new->lock, NULL);

	return new;
}


/**
 * reflist_new:
 *
 * Creates a new reflection list.
 *
 * Returns: the new reflection list, or NULL on error.
 */
RefList *reflist_new()
{
	RefList *new;

	new = malloc(sizeof(struct _reflist));
	if ( new == NULL ) return NULL;

	new->head = NULL;

	return new;
}


/**
 * reflection_new:
 * @h: The h index of the new reflection
 * @k: The k index of the new reflection
 * @l: The l index of the new reflection
 *
 * Creates a new individual reflection.  You'll probably want to use
 * add_refl_to_list() at some later point.
 */
Reflection *reflection_new(signed int h, signed int k, signed int l)
{
	return new_node(SERIAL(h, k, l));
}


/**
 * reflection_free:
 * @refl: The reflection to free.
 *
 * Destroys an individual reflection.
 */
void reflection_free(Reflection *refl)
{
	pthread_mutex_destroy(&refl->lock);
	free(refl);
}


static void recursive_free(Reflection *refl)
{
	if ( refl->child[0] != NULL ) recursive_free(refl->child[0]);
	if ( refl->child[1] != NULL ) recursive_free(refl->child[1]);

	while ( refl != NULL ) {
		Reflection *next = refl->next;
		reflection_free(refl);
		refl = next;
	}
}


/**
 * reflist_free:
 * @list: The reflection list to free.
 *
 * Destroys a reflection list.
 */
void reflist_free(RefList *list)
{
	if ( list == NULL ) return;
	if ( list->head != NULL ) {
		recursive_free(list->head);
	} /* else empty list */
	free(list);
}


/********************************** Search ************************************/

/**
 * find_refl:
 * @list: The reflection list to search in
 * @h: The 'h' index to search for
 * @k: The 'k' index to search for
 * @l: The 'l' index to search for
 *
 * This function finds the first reflection in 'list' with the given indices.
 *
 * Since a %RefList can contain multiple reflections with the same indices, you
 * may need to use next_found_refl() to get the other reflections.
 *
 * Returns: The found reflection, or NULL if no reflection with the given
 * indices could be found.
 **/
Reflection *find_refl(const RefList *list,
                      signed int h, signed int k, signed int l)
{
	unsigned int search = SERIAL(h, k, l);
	Reflection *refl;

	if ( list->head == NULL ) return NULL;

	/* Indices greater than or equal to 256 are filtered out when
	 * reflections are added, so don't even bother looking.
	 * (also, looking for such reflections causes trouble because the search
	 * serial number would be invalid) */
	if ( abs(h) >= 256 ) return NULL;
	if ( abs(k) >= 256 ) return NULL;
	if ( abs(l) >= 256 ) return NULL;

	refl = list->head;

	while ( refl != NULL ) {

		if ( refl->serial == search ) {

			assert(search == refl->serial);
			assert(h == GET_H(refl->serial));
			assert(k == GET_K(refl->serial));
			assert(l == GET_L(refl->serial));
			return refl;

		} else {

			int dir = search > refl->serial;
			if ( refl->child[dir] != NULL ) {
				refl = refl->child[dir];
			} else {
				/* Hit the bottom of the tree */
				return NULL;
			}

		}

	}

	return NULL;
}


/**
 * next_found_refl:
 * @refl: A reflection returned by find_refl() or next_found_refl()
 *
 * This function returns the next reflection in @refl's list with the same
 * indices.
 *
 * Returns: The found reflection, or NULL if there are no more reflections with
 * the same indices.
 **/
Reflection *next_found_refl(Reflection *refl)
{
	if ( refl->next != NULL ) assert(refl->serial == refl->next->serial);

	return refl->next;  /* Well, that was easy... */
}


/********************************** Getters ***********************************/

/**
 * get_excitation_error:
 * @refl: A %Reflection
 *
 * Returns: The excitation error for the reflection.
 **/
double get_excitation_error(const Reflection *refl)
{
	return refl->data.excitation_error;
}


/**
 * get_detector_pos:
 * @refl: A %Reflection
 * @fs: Location at which to store the fast scan offset of the reflection
 * @ss: Location at which to store the slow scan offset of the reflection
 *
 **/
void get_detector_pos(const Reflection *refl, double *fs, double *ss)
{
	*fs = refl->data.fs;
	*ss = refl->data.ss;
}


/**
 * get_indices:
 * @refl: A %Reflection
 * @h: Location at which to store the 'h' index of the reflection
 * @k: Location at which to store the 'k' index of the reflection
 * @l: Location at which to store the 'l' index of the reflection
 *
 **/
void get_indices(const Reflection *refl,
                 signed int *h, signed int *k, signed int *l)
{
	*h = GET_H(refl->serial);
	*k = GET_K(refl->serial);
	*l = GET_L(refl->serial);
}


/**
 * get_symmetric_indices:
 * @refl: A %Reflection
 * @hs: Location at which to store the 'h' index of the reflection
 * @ks: Location at which to store the 'k' index of the reflection
 * @ls: Location at which to store the 'l' index of the reflection
 *
 * This function gives the symmetric indices, that is, the "real" indices before
 * squashing down to the asymmetric reciprocal unit.  This may be useful if the
 * list is indexed according to the asymmetric indices, but you still need
 * access to the symmetric version.  This happens during post-refinement.
 *
 **/
void get_symmetric_indices(const Reflection *refl,
                                  signed int *hs, signed int *ks,
                                  signed int *ls)
{
	*hs = refl->data.hs;
	*ks = refl->data.ks;
	*ls = refl->data.ls;
}


/**
 * get_partiality:
 * @refl: A %Reflection
 *
 * Returns: The partiality of the reflection.
 **/
double get_partiality(const Reflection *refl)
{
	return refl->data.p;
}


/**
 * get_intensity:
 * @refl: A %Reflection
 *
 * Returns: The intensity of the reflection.
 **/
double get_intensity(const Reflection *refl)
{
	return refl->data.intensity;
}


/**
 * get_partial:
 * @refl: A %Reflection
 * @r1: Location at which to store the first excitation error
 * @r2: Location at which to store the second excitation error
 * @p: Location at which to store the partiality
 * @clamp_low: Location at which to store the first clamp status
 * @clamp_high: Location at which to store the second clamp status
 *
 * This function is used during post refinement (in conjunction with
 * set_partial()) to get access to the details of the partiality calculation.
 *
 **/
void get_partial(const Reflection *refl, double *r1, double *r2, double *p,
                 int *clamp_low, int *clamp_high)
{
	*r1 = refl->data.r1;
	*r2 = refl->data.r2;
	*p = get_partiality(refl);
	*clamp_low = refl->data.clamp1;
	*clamp_high = refl->data.clamp2;
}


/**
 * get_scalable:
 * @refl: A %Reflection
 *
 * Returns: non-zero if this reflection can be scaled.
 *
 **/
int get_scalable(const Reflection *refl)
{
	return refl->data.scalable;
}


/**
 * get_refinable:
 * @refl: A %Reflection
 *
 * Returns: non-zero if this reflection can be used for post refinement.
 *
 **/
int get_refinable(const Reflection *refl)
{
	return refl->data.refinable;
}


/**
 * get_redundancy:
 * @refl: A %Reflection
 *
 * The redundancy of the reflection is the number of measurements that have been
 * made of it.  Note that a redundancy of zero may have a special meaning, such
 * as that the reflection was impossible to integrate.  Note further that each
 * reflection in the list has its own redundancy, even if there are multiple
 * copies of the reflection in the list.  The total number of reflection
 * measurements should always be the sum of the redundancies in the entire list.
 *
 * Returns: the number of measurements of this reflection.
 *
 **/
int get_redundancy(const Reflection *refl)
{
	return refl->data.redundancy;
}


/**
 * get_esd_intensity:
 * @refl: A %Reflection
 *
 * Returns: the standard error in the intensity measurement (as returned by
 * get_intensity()) for this reflection.
 *
 **/
double get_esd_intensity(const Reflection *refl)
{
	return refl->data.esd_i;
}


/**
 * get_phase:
 * @refl: A %Reflection
 * @have_phase: Place to store a non-zero value if the phase is set, or NULL.
 *
 * Returns: the phase for this reflection.
 *
 **/
double get_phase(const Reflection *refl, int *have_phase)
{
	if ( have_phase != NULL ) *have_phase = refl->data.have_phase;
	return refl->data.phase;
}


/**
 * get_temp1:
 * @refl: A %Reflection
 *
 * The temporary values can be used according to the needs of the calling
 * program.
 *
 * Returns: the first temporary value for this reflection.
 *
 **/
double get_temp1(const Reflection *refl)
{
	return refl->data.temp1;
}


/**
 * get_temp2:
 * @refl: A %Reflection
 *
 * The temporary values can be used according to the needs of the calling
 * program.
 *
 * Returns: the second temporary value for this reflection.
 *
 **/
double get_temp2(const Reflection *refl)
{
	return refl->data.temp2;
}


/********************************** Setters ***********************************/

/**
 * copy_data:
 * @to: %Reflection to copy data into
 * @from: %Reflection to copy data from
 *
 * This function is used to copy the data (which is everything listed above in
 * the list of getters and setters, apart from the indices themselves) from one
 * reflection to another.  This might be used when creating a new list from an
 * old one, perhaps using the asymmetric indices instead of the raw indices for
 * the new list.
 *
 **/
void copy_data(Reflection *to, const Reflection *from)
{
	memcpy(&to->data, &from->data, sizeof(struct _refldata));
}


/**
 * set_detector_pos:
 * @refl: A %Reflection
 * @exerr: The excitation error for this reflection
 * @fs: The fast scan offset of the reflection
 * @ss: The slow scan offset of the reflection
 *
 **/
void set_detector_pos(Reflection *refl, double exerr, double fs, double ss)
{
	refl->data.excitation_error = exerr;
	refl->data.fs = fs;
	refl->data.ss = ss;
}


/**
 * set_partial:
 * @refl: A %Reflection
 * @r1: The first excitation error
 * @r2: The second excitation error
 * @p: The partiality
 * @clamp_low: The first clamp status
 * @clamp_high: The second clamp status
 *
 * This function is used during post refinement (in conjunction with
 * get_partial()) to get access to the details of the partiality calculation.
 *
 **/
void set_partial(Reflection *refl, double r1, double r2, double p,
                 double clamp_low, double clamp_high)
{
	refl->data.r1 = r1;
	refl->data.r2 = r2;
	refl->data.p = p;
	refl->data.clamp1 = clamp_low;
	refl->data.clamp2 = clamp_high;
}


/**
 * set_intensity:
 * @refl: A %Reflection
 * @intensity: The intensity for the reflection.
 *
 * Set the intensity for the reflection.  Note that retrieval is done with
 * get_intensity().
 **/
void set_intensity(Reflection *refl, double intensity)
{
	refl->data.intensity = intensity;
}


/**
 * set_scalable:
 * @refl: A %Reflection
 * @scalable: Non-zero if this reflection should be scaled.
 *
 **/
void set_scalable(Reflection *refl, int scalable)
{
	refl->data.scalable = scalable;
}


/**
 * set_refinable:
 * @refl: A %Reflection
 * @refinable: Non-zero if this reflection can be used for post refinement.
 *
 **/
void set_refinable(Reflection *refl, int refinable)
{
	refl->data.refinable = refinable;
}


/**
 * set_redundancy:
 * @refl: A %Reflection
 * @red: New redundancy for the reflection
 *
 * The redundancy of the reflection is the number of measurements that have been
 * made of it.  Note that a redundancy of zero may have a special meaning, such
 * as that the reflection was impossible to integrate.  Note further that each
 * reflection in the list has its own redundancy, even if there are multiple
 * copies of the reflection in the list.  The total number of reflection
 * measurements should always be the sum of the redundancies in the entire list.
 *
 **/
void set_redundancy(Reflection *refl, int red)
{
	refl->data.redundancy = red;
}


/**
 * set_esd_intensity:
 * @refl: A %Reflection
 * @esd: New standard error for this reflection's intensity measurement
 *
 **/
void set_esd_intensity(Reflection *refl, double esd)
{
	refl->data.esd_i = esd;
}


/**
 * set_phase:
 * @refl: A %Reflection
 * @phase: New phase for the reflection
 *
 **/
void set_phase(Reflection *refl, double phase)
{
	refl->data.phase = phase;
	refl->data.have_phase = 1;
}


/**
 * set_symmetric_indices:
 * @refl: A %Reflection
 * @hs: The 'h' index of the reflection
 * @ks: The 'k' index of the reflection
 * @ls: The 'l' index of the reflection
 *
 * This function gives the symmetric indices, that is, the "real" indices before
 * squashing down to the asymmetric reciprocal unit.  This may be useful if the
 * list is indexed according to the asymmetric indices, but you still need
 * access to the symmetric version.  This happens during post-refinement.
 *
 **/
void set_symmetric_indices(Reflection *refl,
                           signed int hs, signed int ks, signed int ls)
{
	refl->data.hs = hs;
	refl->data.ks = ks;
	refl->data.ls = ls;
}


/**
 * set_temp1
 * @refl: A %Reflection
 * @temp: New temporary value for the reflection
 *
 * The temporary values can be used according to the needs of the calling
 * program.
 *
 **/
void set_temp1(Reflection *refl, double temp)
{
	refl->data.temp1 = temp;
}


/**
 * set_temp2
 * @refl: A %Reflection
 * @temp: New temporary value for the reflection
 *
 * The temporary values can be used according to the needs of the calling
 * program.
 *
 **/
void set_temp2(Reflection *refl, double temp)
{
	refl->data.temp2 = temp;
}


/********************************* Insertion **********************************/

static Reflection *rotate_once(Reflection *refl, int dir)
{
	Reflection *s = refl->child[!dir];

	refl->child[!dir] = s->child[dir];
	s->child[dir] = refl;

	refl->col = RED;
	s->col = BLACK;

	return s;
}


static Reflection *rotate_twice(Reflection *refl, int dir)
{
	refl->child[!dir] = rotate_once(refl->child[!dir], !dir);
	return rotate_once(refl, dir);
}


static int is_red(Reflection *refl)
{
	return (refl != NULL) && (refl->col == RED);
}


static Reflection *insert_node(Reflection *refl, Reflection *new)
{
	if ( refl == NULL ) {

		refl = new;

	} else {

		int dir;
		Reflection *rcd;

		assert(new->serial != refl->serial);
		dir = new->serial > refl->serial;
		refl->child[dir] = insert_node(refl->child[dir], new);

		rcd = refl->child[dir];
		if ( is_red(rcd) ) {

			if ( is_red(refl->child[!dir]) ) {

				refl->col = RED;
				refl->child[0]->col = BLACK;
				refl->child[1]->col = BLACK;

			} else {

				if ( is_red(rcd->child[dir] ) ) {
					refl = rotate_once(refl, !dir);
				} else if ( is_red(rcd->child[!dir] ) ) {
					refl = rotate_twice(refl, !dir);
				}

			}
		}

	}

	return refl;
}


static void add_to_list(RefList *list, Reflection *new,
                        signed int h, signed int k, signed int l)
{
	Reflection *f;

	f = find_refl(list, h, k, l);
	if ( f == NULL ) {

		list->head = insert_node(list->head, new);
		list->head->col = BLACK;

	} else {

		/* New reflection is identical to a previous one */
		while ( f->next != NULL ) {
			f = f->next;
		}
		f->next = new;
		new->prev = f;
	}
}


/**
 * add_refl
 * @list: A %RefList
 * @h: The 'h' index of the reflection
 * @k: The 'k' index of the reflection
 * @l: The 'l' index of the reflection
 *
 * Adds a new reflection to @list.  Note that the implementation allows there to
 * be multiple reflections with the same indices in the list, so this function
 * should succeed even if the given indices already feature in the list.
 *
 * Returns: The newly created reflection, or NULL on failure.
 *
 **/
Reflection *add_refl(RefList *list, signed int h, signed int k, signed int l)
{
	Reflection *new;

	assert(abs(h)<256);
	assert(abs(k)<256);
	assert(abs(l)<256);

	new = new_node(SERIAL(h, k, l));
	if ( new == NULL ) return NULL;

	add_to_list(list, new, h, k, l);

	return new;
}


/**
 * add_refl_to_list
 * @refl: A %Reflection
 * @list: A %RefList
 *
 * Adds a @refl to @list.
 *
 **/
void add_refl_to_list(Reflection *refl, RefList *list)
{
	signed int h, k, l;

	get_indices(refl, &h, &k, &l);

	add_to_list(list, refl, h, k, l);
}


/********************************* Iteration **********************************/

struct _reflistiterator {

	int stack_size;
	int stack_ptr;
	Reflection **stack;

};


/**
 * first_refl:
 * @list: A %RefList to iterate over
 * @piter: Address at which to store a %RefListIterator
 *
 * This function sets up the state required for iteration over the entire list,
 * and then returns the first reflection in the list.  An iterator object will
 * be created and its address stored at the location given in piter.
 *
 * Returns: the first reflection in the list.
 *
 **/
Reflection *first_refl(RefList *list, RefListIterator **piter)
{
	RefListIterator *iter;

	iter = malloc(sizeof(struct _reflistiterator));
	iter->stack_size = 32;
	iter->stack = malloc(iter->stack_size*sizeof(Reflection *));
	iter->stack_ptr = 0;
	*piter = iter;

	Reflection *refl = list->head;

	do {

		if ( refl != NULL ) {
			iter->stack[iter->stack_ptr++] = refl;
			if ( iter->stack_ptr == iter->stack_size ) {
				iter->stack_size += 32;
				iter->stack = realloc(iter->stack,
				         iter->stack_size*sizeof(Reflection *));
			}
			refl = refl->child[0];
			continue;
		}

		if ( iter->stack_ptr == 0 ) {
			free(iter->stack);
			free(iter);
			return NULL;
		}

		refl = iter->stack[--iter->stack_ptr];

		return refl;

	} while ( 1 );
}


/**
 * next_refl:
 * @refl: A reflection
 * @iter: A %RefListIterator
 *
 * This function looks up the next reflection in the list that was given earlier
 * to first_refl().
 *
 * Returns: the next reflection in the list, or NULL if no more.
 *
 **/
Reflection *next_refl(Reflection *refl, RefListIterator *iter)
{
	int returned = 1;

	do {

		if ( returned ) refl = refl->child[1];
		returned = 0;

		if ( refl != NULL ) {

			iter->stack[iter->stack_ptr++] = refl;
			if ( iter->stack_ptr == iter->stack_size ) {
				iter->stack_size += 32;
				iter->stack = realloc(iter->stack,
				         iter->stack_size*sizeof(Reflection *));
			}
			refl = refl->child[0];
			continue;

		}
		if ( iter->stack_ptr == 0 ) {
			free(iter->stack);
			free(iter);
			return NULL;
		}

		return iter->stack[--iter->stack_ptr];

	} while ( 1 );
}


/*********************************** Voodoo ***********************************/

static int recursive_depth(Reflection *refl)
{
	int depth_left, depth_right;

	if ( refl == NULL ) return 0;

	depth_left = recursive_depth(refl->child[0]);
	depth_right = recursive_depth(refl->child[1]);

	return 1 + biggest(depth_left, depth_right);
}


static int recursive_count(Reflection *refl)
{
	int count_left, count_right;

	if ( refl == NULL ) return 0;

	count_left = recursive_count(refl->child[0]);
	count_right = recursive_count(refl->child[1]);

	return 1 + count_left + count_right;
}


/**
 * num_reflections:
 * @list: A %RefList
 *
 * Returns: the number of reflections in @list.
 *
 **/
int num_reflections(RefList *list)
{
	return recursive_count(list->head);
}


/**
 * tree_depth:
 * @list: A %RefList
 *
 * If the depth of the tree is more than about 20, access to the list will be
 * slow.  This should never happen.
 *
 * Returns: the depth of the RB-tree used internally to represent @list.
 *
 **/
int tree_depth(RefList *list)
{
	return recursive_depth(list->head);
}


/**
 * lock_reflection:
 * @refl: A %Reflection
 *
 * Acquires a lock on the reflection.
 */
void lock_reflection(Reflection *refl)
{
	pthread_mutex_lock(&refl->lock);
}


/**
 * unlock_reflection:
 * @refl: A %Reflection
 *
 * Releases a lock on the reflection.
 */
void unlock_reflection(Reflection *refl)
{
	pthread_mutex_unlock(&refl->lock);
}