summaryrefslogtreecommitdiff
path: root/src/libcamera/controls.cpp
blob: 5aef4e7145bd2a86bea8de562c04850c58427314 (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
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * controls.cpp - Control handling
 */

#include <libcamera/controls.h>

#include <iomanip>
#include <sstream>
#include <string>
#include <string.h>

#include "libcamera/internal/control_validator.h"
#include "libcamera/internal/log.h"
#include "libcamera/internal/utils.h"

/**
 * \file controls.h
 * \brief Framework to manage controls related to an object
 *
 * A control is a mean to govern or influence the operation of an object, and in
 * particular of a camera. Every control is defined by a unique numerical ID, a
 * name string and the data type of the value it stores. The libcamera API
 * defines a set of standard controls in the libcamera::controls namespace, as
 * a set of instances of the Control class.
 *
 * The main way for applications to interact with controls is through the
 * ControlList stored in the Request class:
 *
 * \code{.cpp}
 * Request *req = ...;
 * ControlList &controls = req->controls();
 * controls->set(controls::AwbEnable, false);
 * controls->set(controls::ManualExposure, 1000);
 *
 * ...
 *
 * int32_t exposure = controls->get(controls::ManualExposure);
 * \endcode
 *
 * The ControlList::get() and ControlList::set() methods automatically deduce
 * the data type based on the control.
 */

namespace libcamera {

LOG_DEFINE_CATEGORY(Controls)

namespace {

static constexpr size_t ControlValueSize[] = {
	[ControlTypeNone]		= 0,
	[ControlTypeBool]		= sizeof(bool),
	[ControlTypeByte]		= sizeof(uint8_t),
	[ControlTypeInteger32]		= sizeof(int32_t),
	[ControlTypeInteger64]		= sizeof(int64_t),
	[ControlTypeFloat]		= sizeof(float),
	[ControlTypeString]		= sizeof(char),
	[ControlTypeRectangle]		= sizeof(Rectangle),
	[ControlTypeSize]		= sizeof(Size),
};

} /* namespace */

/**
 * \enum ControlType
 * \brief Define the data type of a Control
 * \var ControlTypeNone
 * Invalid type, for empty values
 * \var ControlTypeBool
 * The control stores a boolean value
 * \var ControlTypeByte
 * The control stores a byte value as an unsigned 8-bit integer
 * \var ControlTypeInteger32
 * The control stores a 32-bit integer value
 * \var ControlTypeInteger64
 * The control stores a 64-bit integer value
 * \var ControlTypeFloat
 * The control stores a 32-bit floating point value
 * \var ControlTypeString
 * The control stores a string value as an array of char
 */

/**
 * \class ControlValue
 * \brief Abstract type representing the value of a control
 */

/** \todo Revisit the ControlValue layout when stabilizing the ABI */
static_assert(sizeof(ControlValue) == 16, "Invalid size of ControlValue class");

/**
 * \brief Construct an empty ControlValue.
 */
ControlValue::ControlValue()
	: type_(ControlTypeNone), isArray_(false), numElements_(0)
{
}

/**
 * \fn template<typename T> T ControlValue::ControlValue(const T &value)
 * \brief Construct a ControlValue of type T
 * \param[in] value Initial value
 *
 * This function constructs a new instance of ControlValue and stores the \a
 * value inside it. If the type \a T is equivalent to Span<R>, the instance
 * stores an array of values of type \a R. Otherwise the instance stores a
 * single value of type \a T. The numElements() and type() are updated to
 * reflect the stored value.
 */

void ControlValue::release()
{
	std::size_t size = numElements_ * ControlValueSize[type_];

	if (size > sizeof(value_)) {
		delete[] reinterpret_cast<uint8_t *>(storage_);
		storage_ = nullptr;
	}
}

ControlValue::~ControlValue()
{
	release();
}

/**
 * \brief Construct a ControlValue with the content of \a other
 * \param[in] other The ControlValue to copy content from
 */
ControlValue::ControlValue(const ControlValue &other)
	: type_(ControlTypeNone), numElements_(0)
{
	*this = other;
}

/**
 * \brief Replace the content of the ControlValue with a copy of the content
 * of \a other
 * \param[in] other The ControlValue to copy content from
 * \return The ControlValue with its content replaced with the one of \a other
 */
ControlValue &ControlValue::operator=(const ControlValue &other)
{
	set(other.type_, other.isArray_, other.data().data(),
	    other.numElements_, ControlValueSize[other.type_]);
	return *this;
}

/**
 * \fn ControlValue::type()
 * \brief Retrieve the data type of the value
 * \return The value data type
 */

/**
 * \fn ControlValue::isNone()
 * \brief Determine if the value is not initialised
 * \return True if the value type is ControlTypeNone, false otherwise
 */

/**
 * \fn ControlValue::isArray()
 * \brief Determine if the value stores an array
 * \return True if the value stores an array, false otherwise
 */

/**
 * \fn ControlValue::numElements()
 * \brief Retrieve the number of elements stored in the ControlValue
 *
 * For instances storing an array, this function returns the number of elements
 * in the array. For instances storing a string, it returns the length of the
 * string, not counting the terminating '\0'. Otherwise, it returns 1.
 *
 * \return The number of elements stored in the ControlValue
 */

/**
 * \brief Retrieve the raw data of a control value
 * \return The raw data of the control value as a span of uint8_t
 */
Span<const uint8_t> ControlValue::data() const
{
	std::size_t size = numElements_ * ControlValueSize[type_];
	const uint8_t *data = size > sizeof(value_)
			    ? reinterpret_cast<const uint8_t *>(storage_)
			    : reinterpret_cast<const uint8_t *>(&value_);
	return { data, size };
}

/**
 * \copydoc ControlValue::data() const
 */
Span<uint8_t> ControlValue::data()
{
	Span<const uint8_t> data = const_cast<const ControlValue *>(this)->data();
	return { const_cast<uint8_t *>(data.data()), data.size() };
}

/**
 * \brief Assemble and return a string describing the value
 * \return A string describing the ControlValue
 */
std::string ControlValue::toString() const
{
	if (type_ == ControlTypeNone)
		return "<ValueType Error>";

	const uint8_t *data = ControlValue::data().data();

	if (type_ == ControlTypeString)
		return std::string(reinterpret_cast<const char *>(data),
				   numElements_);

	std::string str(isArray_ ? "[ " : "");

	for (unsigned int i = 0; i < numElements_; ++i) {
		switch (type_) {
		case ControlTypeBool: {
			const bool *value = reinterpret_cast<const bool *>(data);
			str += *value ? "true" : "false";
			break;
		}
		case ControlTypeByte: {
			const uint8_t *value = reinterpret_cast<const uint8_t *>(data);
			str += std::to_string(*value);
			break;
		}
		case ControlTypeInteger32: {
			const int32_t *value = reinterpret_cast<const int32_t *>(data);
			str += std::to_string(*value);
			break;
		}
		case ControlTypeInteger64: {
			const int64_t *value = reinterpret_cast<const int64_t *>(data);
			str += std::to_string(*value);
			break;
		}
		case ControlTypeFloat: {
			const float *value = reinterpret_cast<const float *>(data);
			str += std::to_string(*value);
			break;
		}
		case ControlTypeRectangle: {
			const Rectangle *value = reinterpret_cast<const Rectangle *>(data);
			str += value->toString();
			break;
		}
		case ControlTypeSize: {
			const Size *value = reinterpret_cast<const Size *>(data);
			str += value->toString();
			break;
		}
		case ControlTypeNone:
		case ControlTypeString:
			break;
		}

		if (i + 1 != numElements_)
			str += ", ";

		data += ControlValueSize[type_];
	}

	if (isArray_)
		str += " ]";

	return str;
}

/**
 * \brief Compare ControlValue instances for equality
 * \return True if the values have identical types and values, false otherwise
 */
bool ControlValue::operator==(const ControlValue &other) const
{
	if (type_ != other.type_)
		return false;

	if (numElements_ != other.numElements())
		return false;

	if (isArray_ != other.isArray_)
		return false;

	return memcmp(data().data(), other.data().data(), data().size()) == 0;
}

/**
 * \fn bool ControlValue::operator!=()
 * \brief Compare ControlValue instances for non equality
 * \return False if the values have identical types and values, true otherwise
 */

/**
 * \fn template<typename T> T ControlValue::get() const
 * \brief Get the control value
 *
 * This function returns the contained value as an instance of \a T. If the
 * ControlValue instance stores a single value, the type \a T shall match the
 * stored value type(). If the instance stores an array of values, the type
 * \a T should be equal to Span<const R>, and the type \a R shall match the
 * stored value type(). The behaviour is undefined otherwise.
 *
 * Note that a ControlValue instance that stores a non-array value is not
 * equivalent to an instance that stores an array value containing a single
 * element. The latter shall be accessed through a Span<const R> type, while
 * the former shall be accessed through a type \a T corresponding to type().
 *
 * \return The control value
 */

/**
 * \fn template<typename T> void ControlValue::set(const T &value)
 * \brief Set the control value to \a value
 * \param[in] value The control value
 *
 * This function stores the \a value in the instance. If the type \a T is
 * equivalent to Span<R>, the instance stores an array of values of type \a R.
 * Otherwise the instance stores a single value of type \a T. The numElements()
 * and type() are updated to reflect the stored value.
 *
 * The entire content of \a value is copied to the instance, no reference to \a
 * value or to the data it references is retained. This may be an expensive
 * operation for Span<> values that refer to large arrays.
 */

void ControlValue::set(ControlType type, bool isArray, const void *data,
		       std::size_t numElements, std::size_t elementSize)
{
	ASSERT(elementSize == ControlValueSize[type]);

	reserve(type, isArray, numElements);

	Span<uint8_t> storage = ControlValue::data();
	memcpy(storage.data(), data, storage.size());
}

/**
 * \brief Set the control type and reserve memory
 * \param[in] type The control type
 * \param[in] isArray True to make the value an array
 * \param[in] numElements The number of elements
 *
 * This function sets the type of the control value to \a type, and reserves
 * memory to store the control value. If \a isArray is true, the instance
 * becomes an array control and storage for \a numElements is reserved.
 * Otherwise the instance becomes a simple control, numElements is ignored, and
 * storage for the single element is reserved.
 */
void ControlValue::reserve(ControlType type, bool isArray, std::size_t numElements)
{
	if (!isArray)
		numElements = 1;

	std::size_t oldSize = numElements_ * ControlValueSize[type_];
	std::size_t newSize = numElements * ControlValueSize[type];

	if (oldSize != newSize)
		release();

	type_ = type;
	isArray_ = isArray;
	numElements_ = numElements;

	if (oldSize == newSize)
		return;

	if (newSize > sizeof(value_))
		storage_ = reinterpret_cast<void *>(new uint8_t[newSize]);
}

/**
 * \class ControlId
 * \brief Control static metadata
 *
 * The ControlId class stores a control ID, name and data type. It provides
 * unique identification of a control, but without support for compile-time
 * type deduction that the derived template Control class supports. See the
 * Control class for more information.
 */

/**
 * \fn ControlId::ControlId(unsigned int id, const std::string &name, ControlType type)
 * \brief Construct a ControlId instance
 * \param[in] id The control numerical ID
 * \param[in] name The control name
 * \param[in] type The control data type
 */

/**
 * \fn unsigned int ControlId::id() const
 * \brief Retrieve the control numerical ID
 * \return The control numerical ID
 */

/**
 * \fn const char *ControlId::name() const
 * \brief Retrieve the control name
 * \return The control name
 */

/**
 * \fn ControlType ControlId::type() const
 * \brief Retrieve the control data type
 * \return The control data type
 */

/**
 * \fn bool operator==(unsigned int lhs, const ControlId &rhs)
 * \brief Compare a ControlId with a control numerical ID
 * \param[in] lhs Left-hand side numerical ID
 * \param[in] rhs Right-hand side ControlId
 *
 * \return True if \a lhs is equal to \a rhs.id(), false otherwise
 */

/**
 * \fn bool operator==(const ControlId &lhs, unsigned int rhs)
 * \brief Compare a ControlId with a control numerical ID
 * \param[in] lhs Left-hand side ControlId
 * \param[in] rhs Right-hand side numerical ID
 *
 * \return True if \a lhs.id() is equal to \a rhs, false otherwise
 */

/**
 * \class Control
 * \brief Describe a control and its intrinsic properties
 *
 * The Control class models a control exposed by an object. Its template type
 * name T refers to the control data type, and allows methods that operate on
 * control values to be defined as template methods using the same type T for
 * the control value. See for instance how the ControlList::get() method
 * returns a value corresponding to the type of the requested control.
 *
 * While this class is the main means to refer to a control, the control
 * identifying information is stored in the non-template base ControlId class.
 * This allows code that operates on a set of controls of different types to
 * reference those controls through a ControlId instead of a Control. For
 * instance, the list of controls supported by a camera is exposed as ControlId
 * instead of Control.
 *
 * Controls of any type can be defined through template specialisation, but
 * libcamera only supports the bool, uint8_t, int32_t, int64_t and float types
 * natively (this includes types that are equivalent to the supported types,
 * such as int and long int).
 *
 * Controls IDs shall be unique. While nothing prevents multiple instances of
 * the Control class to be created with the same ID for the same object, doing
 * so may cause undefined behaviour.
 */

/**
 * \fn Control::Control(unsigned int id, const char *name)
 * \brief Construct a Control instance
 * \param[in] id The control numerical ID
 * \param[in] name The control name
 *
 * The control data type is automatically deduced from the template type T.
 */

/**
 * \typedef Control::type
 * \brief The Control template type T
 */

/**
 * \class ControlInfo
 * \brief Describe the limits of valid values for a Control
 *
 * The ControlInfo expresses the constraints on valid values for a control.
 * The constraints depend on the object the control applies to, and are
 * constant for the lifetime of that object. They are typically constructed by
 * pipeline handlers to describe the controls they support.
 */

/**
 * \brief Construct a ControlInfo with minimum and maximum range parameters
 * \param[in] min The control minimum value
 * \param[in] max The control maximum value
 * \param[in] def The control default value
 */
ControlInfo::ControlInfo(const ControlValue &min,
			 const ControlValue &max,
			 const ControlValue &def)
	: min_(min), max_(max), def_(def)
{
}

/**
 * \brief Construct a ControlInfo from the list of valid values
 * \param[in] values The control valid values
 * \param[in] def The control default value
 *
 * Construct a ControlInfo from a list of valid values. The ControlInfo
 * minimum and maximum values are set to the first and last members of the
 * values list respectively. The default value is set to \a def if provided, or
 * to the minimum value otherwise.
 */
ControlInfo::ControlInfo(Span<const ControlValue> values,
			 const ControlValue &def)
{
	min_ = values.front();
	max_ = values.back();
	def_ = !def.isNone() ? def : values.front();

	values_.reserve(values.size());
	for (const ControlValue &value : values)
		values_.push_back(value);
}

/**
 * \fn ControlInfo::min()
 * \brief Retrieve the minimum value of the control
 *
 * For string controls, this is the minimum length of the string, not counting
 * the terminating '\0'. For all other control types, this is the minimum value
 * of each element.
 *
 * \return A ControlValue with the minimum value for the control
 */

/**
 * \fn ControlInfo::max()
 * \brief Retrieve the maximum value of the control
 *
 * For string controls, this is the maximum length of the string, not counting
 * the terminating '\0'. For all other control types, this is the maximum value
 * of each element.
 *
 * \return A ControlValue with the maximum value for the control
 */

/**
 * \fn ControlInfo::def()
 * \brief Retrieve the default value of the control
 * \return A ControlValue with the default value for the control
 */

/**
 * \fn ControlInfo::values()
 * \brief Retrieve the list of valid values
 *
 * For controls that support a pre-defined number of values, the enumeration of
 * those is reported through a vector of ControlValue instances accessible with
 * this method.
 *
 * \return A vector of ControlValue representing the control valid values
 */

/**
 * \brief Provide a string representation of the ControlInfo
 */
std::string ControlInfo::toString() const
{
	std::stringstream ss;

	ss << "[" << min_.toString() << ".." << max_.toString() << "]";

	return ss.str();
}

/**
 * \fn bool ControlInfo::operator==()
 * \brief Compare ControlInfo instances for equality
 * \return True if the constraints have identical min and max, false otherwise
 */

/**
 * \fn bool ControlInfo::operator!=()
 * \brief Compare ControlInfo instances for non equality
 * \return True if the constraints have different min and max, false otherwise
 */

/**
 * \typedef ControlIdMap
 * \brief A map of numerical control ID to ControlId
 *
 * The map is used by ControlList instances to access controls by numerical
 * IDs. A global map of all libcamera controls is provided by
 * controls::controls.
 */

/**
 * \class ControlInfoMap
 * \brief A map of ControlId to ControlInfo
 *
 * The ControlInfoMap class describes controls supported by an object as an
 * unsorted map of ControlId pointers to ControlInfo instances. Unlike the
 * standard std::unsorted_map<> class, it is designed the be immutable once
 * constructed, and thus only exposes the read accessors of the
 * std::unsorted_map<> base class.
 *
 * In addition to the features of the standard unsorted map, this class also
 * provides access to the mapped elements using numerical ID keys. It maintains
 * an internal map of numerical ID to ControlId for this purpose, and exposes it
 * through the idmap() method to help construction of ControlList instances.
 */

/**
 * \typedef ControlInfoMap::Map
 * \brief The base std::unsorted_map<> container
 */

/**
 * \fn ControlInfoMap::ControlInfoMap(const ControlInfoMap &other)
 * \brief Copy constructor, construct a ControlInfoMap from a copy of \a other
 * \param[in] other The other ControlInfoMap
 */

/**
 * \brief Construct a ControlInfoMap from an initializer list
 * \param[in] init The initializer list
 */
ControlInfoMap::ControlInfoMap(std::initializer_list<Map::value_type> init)
	: Map(init)
{
	generateIdmap();
}

/**
 * \brief Construct a ControlInfoMap from a plain map
 * \param[in] info The control info plain map
 *
 * Construct a new ControlInfoMap and populate its contents with those of
 * \a info using move semantics. Upon return the \a info map will be empty.
 */
ControlInfoMap::ControlInfoMap(Map &&info)
	: Map(std::move(info))
{
	generateIdmap();
}

/**
 * \fn ControlInfoMap &ControlInfoMap::operator=(const ControlInfoMap &other)
 * \brief Copy assignment operator, replace the contents with a copy of \a other
 * \param[in] other The other ControlInfoMap
 * \return A reference to the ControlInfoMap
 */

/**
 * \brief Replace the contents with those from the initializer list
 * \param[in] init The initializer list
 * \return A reference to the ControlInfoMap
 */
ControlInfoMap &ControlInfoMap::operator=(std::initializer_list<Map::value_type> init)
{
	Map::operator=(init);
	generateIdmap();
	return *this;
}

/**
 * \brief Move assignment operator from a plain map
 * \param[in] info The control info plain map
 *
 * Populate the map by replacing its contents with those of \a info using move
 * semantics. Upon return the \a info map will be empty.
 *
 * \return A reference to the populated ControlInfoMap
 */
ControlInfoMap &ControlInfoMap::operator=(Map &&info)
{
	Map::operator=(std::move(info));
	generateIdmap();
	return *this;
}

/**
 * \brief Access specified element by numerical ID
 * \param[in] id The numerical ID
 * \return A reference to the element whose ID is equal to \a id
 */
ControlInfoMap::mapped_type &ControlInfoMap::at(unsigned int id)
{
	return at(idmap_.at(id));
}

/**
 * \brief Access specified element by numerical ID
 * \param[in] id The numerical ID
 * \return A const reference to the element whose ID is equal to \a id
 */
const ControlInfoMap::mapped_type &ControlInfoMap::at(unsigned int id) const
{
	return at(idmap_.at(id));
}

/**
 * \brief Count the number of elements matching a numerical ID
 * \param[in] id The numerical ID
 * \return The number of elements matching the numerical \a id
 */
ControlInfoMap::size_type ControlInfoMap::count(unsigned int id) const
{
	/*
	 * The ControlInfoMap and its idmap have a 1:1 mapping between their
	 * entries, we can thus just count the matching entries in idmap to
	 * avoid an additional lookup.
	 */
	return idmap_.count(id);
}

/**
 * \brief Find the element matching a numerical ID
 * \param[in] id The numerical ID
 * \return An iterator pointing to the element matching the numerical \a id, or
 * end() if no such element exists
 */
ControlInfoMap::iterator ControlInfoMap::find(unsigned int id)
{
	auto iter = idmap_.find(id);
	if (iter == idmap_.end())
		return end();

	return find(iter->second);
}

/**
 * \brief Find the element matching a numerical ID
 * \param[in] id The numerical ID
 * \return A const iterator pointing to the element matching the numerical
 * \a id, or end() if no such element exists
 */
ControlInfoMap::const_iterator ControlInfoMap::find(unsigned int id) const
{
	auto iter = idmap_.find(id);
	if (iter == idmap_.end())
		return end();

	return find(iter->second);
}

/**
 * \fn const ControlIdMap &ControlInfoMap::idmap() const
 * \brief Retrieve the ControlId map
 *
 * Constructing ControlList instances for V4L2 controls requires a ControlIdMap
 * for the V4L2 device that the control list targets. This helper method
 * returns a suitable idmap for that purpose.
 *
 * \return The ControlId map
 */

void ControlInfoMap::generateIdmap()
{
	idmap_.clear();

	for (const auto &ctrl : *this) {
		/*
		 * For string controls, min and max define the valid
		 * range for the string size, not for the individual
		 * values.
		 */
		ControlType rangeType = ctrl.first->type() == ControlTypeString
				      ? ControlTypeInteger32 : ctrl.first->type();
		const ControlInfo &info = ctrl.second;

		if (info.min().type() != rangeType) {
			LOG(Controls, Error)
				<< "Control " << utils::hex(ctrl.first->id())
				<< " type and info type mismatch";
			idmap_.clear();
			clear();
			return;
		}

		idmap_[ctrl.first->id()] = ctrl.first;
	}
}

/**
 * \class ControlList
 * \brief Associate a list of ControlId with their values for an object
 *
 * The ControlList class stores values of controls exposed by an object. The
 * lists returned by the Request::controls() and Request::metadata() methods
 * refer to the camera that the request belongs to.
 *
 * Control lists are constructed with a map of all the controls supported by
 * their object, and an optional ControlValidator to further validate the
 * controls.
 */

/**
 * \brief Construct a ControlList not associated with any object
 *
 * This constructor is meant to support ControlList serialization and shall not
 * be used directly by application.
 */
ControlList::ControlList()
	: validator_(nullptr), idmap_(nullptr), infoMap_(nullptr)
{
}

/**
 * \brief Construct a ControlList with an optional control validator
 * \param[in] idmap The ControlId map for the control list target object
 * \param[in] validator The validator (may be null)
 *
 * For ControlList containing libcamera controls, a global map of all libcamera
 * controls is provided by controls::controls and can be used as the \a idmap
 * argument.
 */
ControlList::ControlList(const ControlIdMap &idmap, ControlValidator *validator)
	: validator_(validator), idmap_(&idmap), infoMap_(nullptr)
{
}

/**
 * \brief Construct a ControlList with the idmap of a control info map
 * \param[in] infoMap The ControlInfoMap for the control list target object
 * \param[in] validator The validator (may be null)
 */
ControlList::ControlList(const ControlInfoMap &infoMap, ControlValidator *validator)
	: validator_(validator), idmap_(&infoMap.idmap()), infoMap_(&infoMap)
{
}

/**
 * \typedef ControlList::iterator
 * \brief Iterator for the controls contained within the list
 */

/**
 * \typedef ControlList::const_iterator
 * \brief Const iterator for the controls contained within the list
 */

/**
 * \fn iterator ControlList::begin()
 * \brief Retrieve an iterator to the first Control in the list
 * \return An iterator to the first Control in the list
 */

/**
 * \fn const_iterator ControlList::begin() const
 * \brief Retrieve a const_iterator to the first Control in the list
 * \return A const_iterator to the first Control in the list
 */

/**
 * \fn iterator ControlList::end()
 * \brief Retrieve an iterator pointing to the past-the-end control in the list
 * \return An iterator to the element following the last control in the list
 */

/**
 * \fn const_iterator ControlList::end() const
 * \brief Retrieve a const iterator pointing to the past-the-end control in the
 * list
 * \return A const iterator to the element following the last control in the
 * list
 */

/**
 * \fn ControlList::empty()
 * \brief Identify if the list is empty
 * \return True if the list does not contain any control, false otherwise
 */

/**
 * \fn ControlList::size()
 * \brief Retrieve the number of controls in the list
 * \return The number of Control entries stored in the list
 */

/**
 * \fn ControlList::clear()
 * \brief Removes all controls from the list
 */

/**
 * \brief Merge the \a source into the ControlList
 * \param[in] source The ControlList to merge into this object
 *
 * Merging two control lists copies elements from the \a source and inserts
 * them in *this. If the \a source contains elements whose key is already
 * present in *this, then those elements are not overwritten.
 *
 * Only control lists created from the same ControlIdMap or ControlInfoMap may
 * be merged. Attempting to do otherwise results in undefined behaviour.
 *
 * \todo Reimplement or implement an overloaded version which internally uses
 * std::unordered_map::merge() and accepts a non-const argument.
 */
void ControlList::merge(const ControlList &source)
{
	/**
	 * \todo: ASSERT that the current and source ControlList are derived
	 * from a compatible ControlIdMap, to prevent undefined behaviour due to
	 * id collisions.
	 *
	 * This can not currently be a direct pointer comparison due to the
	 * duplication of the ControlIdMaps in the isolated IPA use cases.
	 * Furthermore, manually checking each entry of the id map is identical
	 * is expensive.
	 * See https://bugs.libcamera.org/show_bug.cgi?id=31 for further details
	 */

	for (const auto &ctrl : source) {
		if (contains(ctrl.first)) {
			const ControlId *id = idmap_->at(ctrl.first);
			LOG(Controls, Warning)
				<< "Control " << id->name() << " not overwritten";
			continue;
		}

		set(ctrl.first, ctrl.second);
	}
}

/**
 * \brief Check if the list contains a control with the specified \a id
 * \param[in] id The control ID
 *
 * \return True if the list contains a matching control, false otherwise
 */
bool ControlList::contains(const ControlId &id) const
{
	return controls_.find(id.id()) != controls_.end();
}

/**
 * \brief Check if the list contains a control with the specified \a id
 * \param[in] id The control numerical ID
 *
 * \return True if the list contains a matching control, false otherwise
 */
bool ControlList::contains(unsigned int id) const
{
	return controls_.find(id) != controls_.end();
}

/**
 * \fn template<typename T> T ControlList::get(const Control<T> &ctrl) const
 * \brief Get the value of control \a ctrl
 * \param[in] ctrl The control
 *
 * The behaviour is undefined if the control \a ctrl is not present in the
 * list. Use ControlList::contains() to test for the presence of a control in
 * the list before retrieving its value.
 *
 * The control value type shall match the type T, otherwise the behaviour is
 * undefined.
 *
 * \return The control value
 */

/**
 * \fn template<typename T, typename V> void ControlList::set(const Control<T> &ctrl, const V &value)
 * \brief Set the control \a ctrl value to \a value
 * \param[in] ctrl The control
 * \param[in] value The control value
 *
 * This method sets the value of a control in the control list. If the control
 * is already present in the list, its value is updated, otherwise it is added
 * to the list.
 *
 * The behaviour is undefined if the control \a ctrl is not supported by the
 * object that the list refers to.
 */

/**
 * \fn template<typename T, typename V> \
 * void ControlList::set(const Control<T> &ctrl, const std::initializer_list<V> &value)
 * \copydoc ControlList::set(const Control<T> &ctrl, const V &value)
 */

/**
 * \brief Get the value of control \a id
 * \param[in] id The control numerical ID
 *
 * The behaviour is undefined if the control \a id is not present in the list.
 * Use ControlList::contains() to test for the presence of a control in the
 * list before retrieving its value.
 *
 * \return The control value
 */
const ControlValue &ControlList::get(unsigned int id) const
{
	static const ControlValue zero;

	const ControlValue *val = find(id);
	if (!val)
		return zero;

	return *val;
}

/**
 * \brief Set the value of control \a id to \a value
 * \param[in] id The control ID
 * \param[in] value The control value
 *
 * This method sets the value of a control in the control list. If the control
 * is already present in the list, its value is updated, otherwise it is added
 * to the list.
 *
 * The behaviour is undefined if the control \a id is not supported by the
 * object that the list refers to.
 */
void ControlList::set(unsigned int id, const ControlValue &value)
{
	ControlValue *val = find(id);
	if (!val)
		return;

	*val = value;
}

/**
 * \fn ControlList::infoMap()
 * \brief Retrieve the ControlInfoMap used to construct the ControlList
 *
 * \return The ControlInfoMap used to construct the ControlList. ControlList
 * instances constructed with ControlList() or
 * ControlList(const ControlIdMap &idmap, ControlValidator *validator) have no
 * associated ControlInfoMap, nullptr is returned in that case.
 */

const ControlValue *ControlList::find(unsigned int id) const
{
	const auto iter = controls_.find(id);
	if (iter == controls_.end()) {
		LOG(Controls, Error)
			<< "Control " << utils::hex(id) << " not found";

		return nullptr;
	}

	return &iter->second;
}

ControlValue *ControlList::find(unsigned int id)
{
	if (validator_ && !validator_->validate(id)) {
		LOG(Controls, Error)
			<< "Control " << utils::hex(id)
			<< " is not valid for " << validator_->name();
		return nullptr;
	}

	return &controls_[id];
}

} /* namespace libcamera */