File: mapstructure.go

package info (click to toggle)
golang-github-mitchellh-mapstructure 1.1.2-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, experimental, sid
  • size: 196 kB
  • sloc: makefile: 2
file content (1149 lines) | stat: -rw-r--r-- 32,412 bytes parent folder | download
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
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
// Package mapstructure exposes functionality to convert an arbitrary
// map[string]interface{} into a native Go structure.
//
// The Go structure can be arbitrarily complex, containing slices,
// other structs, etc. and the decoder will properly decode nested
// maps and so on into the proper structures in the native Go struct.
// See the examples to see what the decoder is capable of.
package mapstructure

import (
	"encoding/json"
	"errors"
	"fmt"
	"reflect"
	"sort"
	"strconv"
	"strings"
)

// DecodeHookFunc is the callback function that can be used for
// data transformations. See "DecodeHook" in the DecoderConfig
// struct.
//
// The type should be DecodeHookFuncType or DecodeHookFuncKind.
// Either is accepted. Types are a superset of Kinds (Types can return
// Kinds) and are generally a richer thing to use, but Kinds are simpler
// if you only need those.
//
// The reason DecodeHookFunc is multi-typed is for backwards compatibility:
// we started with Kinds and then realized Types were the better solution,
// but have a promise to not break backwards compat so we now support
// both.
type DecodeHookFunc interface{}

// DecodeHookFuncType is a DecodeHookFunc which has complete information about
// the source and target types.
type DecodeHookFuncType func(reflect.Type, reflect.Type, interface{}) (interface{}, error)

// DecodeHookFuncKind is a DecodeHookFunc which knows only the Kinds of the
// source and target types.
type DecodeHookFuncKind func(reflect.Kind, reflect.Kind, interface{}) (interface{}, error)

// DecoderConfig is the configuration that is used to create a new decoder
// and allows customization of various aspects of decoding.
type DecoderConfig struct {
	// DecodeHook, if set, will be called before any decoding and any
	// type conversion (if WeaklyTypedInput is on). This lets you modify
	// the values before they're set down onto the resulting struct.
	//
	// If an error is returned, the entire decode will fail with that
	// error.
	DecodeHook DecodeHookFunc

	// If ErrorUnused is true, then it is an error for there to exist
	// keys in the original map that were unused in the decoding process
	// (extra keys).
	ErrorUnused bool

	// ZeroFields, if set to true, will zero fields before writing them.
	// For example, a map will be emptied before decoded values are put in
	// it. If this is false, a map will be merged.
	ZeroFields bool

	// If WeaklyTypedInput is true, the decoder will make the following
	// "weak" conversions:
	//
	//   - bools to string (true = "1", false = "0")
	//   - numbers to string (base 10)
	//   - bools to int/uint (true = 1, false = 0)
	//   - strings to int/uint (base implied by prefix)
	//   - int to bool (true if value != 0)
	//   - string to bool (accepts: 1, t, T, TRUE, true, True, 0, f, F,
	//     FALSE, false, False. Anything else is an error)
	//   - empty array = empty map and vice versa
	//   - negative numbers to overflowed uint values (base 10)
	//   - slice of maps to a merged map
	//   - single values are converted to slices if required. Each
	//     element is weakly decoded. For example: "4" can become []int{4}
	//     if the target type is an int slice.
	//
	WeaklyTypedInput bool

	// Metadata is the struct that will contain extra metadata about
	// the decoding. If this is nil, then no metadata will be tracked.
	Metadata *Metadata

	// Result is a pointer to the struct that will contain the decoded
	// value.
	Result interface{}

	// The tag name that mapstructure reads for field names. This
	// defaults to "mapstructure"
	TagName string
}

// A Decoder takes a raw interface value and turns it into structured
// data, keeping track of rich error information along the way in case
// anything goes wrong. Unlike the basic top-level Decode method, you can
// more finely control how the Decoder behaves using the DecoderConfig
// structure. The top-level Decode method is just a convenience that sets
// up the most basic Decoder.
type Decoder struct {
	config *DecoderConfig
}

// Metadata contains information about decoding a structure that
// is tedious or difficult to get otherwise.
type Metadata struct {
	// Keys are the keys of the structure which were successfully decoded
	Keys []string

	// Unused is a slice of keys that were found in the raw value but
	// weren't decoded since there was no matching field in the result interface
	Unused []string
}

// Decode takes an input structure and uses reflection to translate it to
// the output structure. output must be a pointer to a map or struct.
func Decode(input interface{}, output interface{}) error {
	config := &DecoderConfig{
		Metadata: nil,
		Result:   output,
	}

	decoder, err := NewDecoder(config)
	if err != nil {
		return err
	}

	return decoder.Decode(input)
}

// WeakDecode is the same as Decode but is shorthand to enable
// WeaklyTypedInput. See DecoderConfig for more info.
func WeakDecode(input, output interface{}) error {
	config := &DecoderConfig{
		Metadata:         nil,
		Result:           output,
		WeaklyTypedInput: true,
	}

	decoder, err := NewDecoder(config)
	if err != nil {
		return err
	}

	return decoder.Decode(input)
}

// DecodeMetadata is the same as Decode, but is shorthand to
// enable metadata collection. See DecoderConfig for more info.
func DecodeMetadata(input interface{}, output interface{}, metadata *Metadata) error {
	config := &DecoderConfig{
		Metadata: metadata,
		Result:   output,
	}

	decoder, err := NewDecoder(config)
	if err != nil {
		return err
	}

	return decoder.Decode(input)
}

// WeakDecodeMetadata is the same as Decode, but is shorthand to
// enable both WeaklyTypedInput and metadata collection. See
// DecoderConfig for more info.
func WeakDecodeMetadata(input interface{}, output interface{}, metadata *Metadata) error {
	config := &DecoderConfig{
		Metadata:         metadata,
		Result:           output,
		WeaklyTypedInput: true,
	}

	decoder, err := NewDecoder(config)
	if err != nil {
		return err
	}

	return decoder.Decode(input)
}

// NewDecoder returns a new decoder for the given configuration. Once
// a decoder has been returned, the same configuration must not be used
// again.
func NewDecoder(config *DecoderConfig) (*Decoder, error) {
	val := reflect.ValueOf(config.Result)
	if val.Kind() != reflect.Ptr {
		return nil, errors.New("result must be a pointer")
	}

	val = val.Elem()
	if !val.CanAddr() {
		return nil, errors.New("result must be addressable (a pointer)")
	}

	if config.Metadata != nil {
		if config.Metadata.Keys == nil {
			config.Metadata.Keys = make([]string, 0)
		}

		if config.Metadata.Unused == nil {
			config.Metadata.Unused = make([]string, 0)
		}
	}

	if config.TagName == "" {
		config.TagName = "mapstructure"
	}

	result := &Decoder{
		config: config,
	}

	return result, nil
}

// Decode decodes the given raw interface to the target pointer specified
// by the configuration.
func (d *Decoder) Decode(input interface{}) error {
	return d.decode("", input, reflect.ValueOf(d.config.Result).Elem())
}

// Decodes an unknown data type into a specific reflection value.
func (d *Decoder) decode(name string, input interface{}, outVal reflect.Value) error {
	var inputVal reflect.Value
	if input != nil {
		inputVal = reflect.ValueOf(input)

		// We need to check here if input is a typed nil. Typed nils won't
		// match the "input == nil" below so we check that here.
		if inputVal.Kind() == reflect.Ptr && inputVal.IsNil() {
			input = nil
		}
	}

	if input == nil {
		// If the data is nil, then we don't set anything, unless ZeroFields is set
		// to true.
		if d.config.ZeroFields {
			outVal.Set(reflect.Zero(outVal.Type()))

			if d.config.Metadata != nil && name != "" {
				d.config.Metadata.Keys = append(d.config.Metadata.Keys, name)
			}
		}
		return nil
	}

	if !inputVal.IsValid() {
		// If the input value is invalid, then we just set the value
		// to be the zero value.
		outVal.Set(reflect.Zero(outVal.Type()))
		if d.config.Metadata != nil && name != "" {
			d.config.Metadata.Keys = append(d.config.Metadata.Keys, name)
		}
		return nil
	}

	if d.config.DecodeHook != nil {
		// We have a DecodeHook, so let's pre-process the input.
		var err error
		input, err = DecodeHookExec(
			d.config.DecodeHook,
			inputVal.Type(), outVal.Type(), input)
		if err != nil {
			return fmt.Errorf("error decoding '%s': %s", name, err)
		}
	}

	var err error
	outputKind := getKind(outVal)
	switch outputKind {
	case reflect.Bool:
		err = d.decodeBool(name, input, outVal)
	case reflect.Interface:
		err = d.decodeBasic(name, input, outVal)
	case reflect.String:
		err = d.decodeString(name, input, outVal)
	case reflect.Int:
		err = d.decodeInt(name, input, outVal)
	case reflect.Uint:
		err = d.decodeUint(name, input, outVal)
	case reflect.Float32:
		err = d.decodeFloat(name, input, outVal)
	case reflect.Struct:
		err = d.decodeStruct(name, input, outVal)
	case reflect.Map:
		err = d.decodeMap(name, input, outVal)
	case reflect.Ptr:
		err = d.decodePtr(name, input, outVal)
	case reflect.Slice:
		err = d.decodeSlice(name, input, outVal)
	case reflect.Array:
		err = d.decodeArray(name, input, outVal)
	case reflect.Func:
		err = d.decodeFunc(name, input, outVal)
	default:
		// If we reached this point then we weren't able to decode it
		return fmt.Errorf("%s: unsupported type: %s", name, outputKind)
	}

	// If we reached here, then we successfully decoded SOMETHING, so
	// mark the key as used if we're tracking metainput.
	if d.config.Metadata != nil && name != "" {
		d.config.Metadata.Keys = append(d.config.Metadata.Keys, name)
	}

	return err
}

// This decodes a basic type (bool, int, string, etc.) and sets the
// value to "data" of that type.
func (d *Decoder) decodeBasic(name string, data interface{}, val reflect.Value) error {
	if val.IsValid() && val.Elem().IsValid() {
		return d.decode(name, data, val.Elem())
	}

	dataVal := reflect.ValueOf(data)

	// If the input data is a pointer, and the assigned type is the dereference
	// of that exact pointer, then indirect it so that we can assign it.
	// Example: *string to string
	if dataVal.Kind() == reflect.Ptr && dataVal.Type().Elem() == val.Type() {
		dataVal = reflect.Indirect(dataVal)
	}

	if !dataVal.IsValid() {
		dataVal = reflect.Zero(val.Type())
	}

	dataValType := dataVal.Type()
	if !dataValType.AssignableTo(val.Type()) {
		return fmt.Errorf(
			"'%s' expected type '%s', got '%s'",
			name, val.Type(), dataValType)
	}

	val.Set(dataVal)
	return nil
}

func (d *Decoder) decodeString(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	dataKind := getKind(dataVal)

	converted := true
	switch {
	case dataKind == reflect.String:
		val.SetString(dataVal.String())
	case dataKind == reflect.Bool && d.config.WeaklyTypedInput:
		if dataVal.Bool() {
			val.SetString("1")
		} else {
			val.SetString("0")
		}
	case dataKind == reflect.Int && d.config.WeaklyTypedInput:
		val.SetString(strconv.FormatInt(dataVal.Int(), 10))
	case dataKind == reflect.Uint && d.config.WeaklyTypedInput:
		val.SetString(strconv.FormatUint(dataVal.Uint(), 10))
	case dataKind == reflect.Float32 && d.config.WeaklyTypedInput:
		val.SetString(strconv.FormatFloat(dataVal.Float(), 'f', -1, 64))
	case dataKind == reflect.Slice && d.config.WeaklyTypedInput,
		dataKind == reflect.Array && d.config.WeaklyTypedInput:
		dataType := dataVal.Type()
		elemKind := dataType.Elem().Kind()
		switch elemKind {
		case reflect.Uint8:
			var uints []uint8
			if dataKind == reflect.Array {
				uints = make([]uint8, dataVal.Len(), dataVal.Len())
				for i := range uints {
					uints[i] = dataVal.Index(i).Interface().(uint8)
				}
			} else {
				uints = dataVal.Interface().([]uint8)
			}
			val.SetString(string(uints))
		default:
			converted = false
		}
	default:
		converted = false
	}

	if !converted {
		return fmt.Errorf(
			"'%s' expected type '%s', got unconvertible type '%s'",
			name, val.Type(), dataVal.Type())
	}

	return nil
}

func (d *Decoder) decodeInt(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	dataKind := getKind(dataVal)
	dataType := dataVal.Type()

	switch {
	case dataKind == reflect.Int:
		val.SetInt(dataVal.Int())
	case dataKind == reflect.Uint:
		val.SetInt(int64(dataVal.Uint()))
	case dataKind == reflect.Float32:
		val.SetInt(int64(dataVal.Float()))
	case dataKind == reflect.Bool && d.config.WeaklyTypedInput:
		if dataVal.Bool() {
			val.SetInt(1)
		} else {
			val.SetInt(0)
		}
	case dataKind == reflect.String && d.config.WeaklyTypedInput:
		i, err := strconv.ParseInt(dataVal.String(), 0, val.Type().Bits())
		if err == nil {
			val.SetInt(i)
		} else {
			return fmt.Errorf("cannot parse '%s' as int: %s", name, err)
		}
	case dataType.PkgPath() == "encoding/json" && dataType.Name() == "Number":
		jn := data.(json.Number)
		i, err := jn.Int64()
		if err != nil {
			return fmt.Errorf(
				"error decoding json.Number into %s: %s", name, err)
		}
		val.SetInt(i)
	default:
		return fmt.Errorf(
			"'%s' expected type '%s', got unconvertible type '%s'",
			name, val.Type(), dataVal.Type())
	}

	return nil
}

func (d *Decoder) decodeUint(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	dataKind := getKind(dataVal)

	switch {
	case dataKind == reflect.Int:
		i := dataVal.Int()
		if i < 0 && !d.config.WeaklyTypedInput {
			return fmt.Errorf("cannot parse '%s', %d overflows uint",
				name, i)
		}
		val.SetUint(uint64(i))
	case dataKind == reflect.Uint:
		val.SetUint(dataVal.Uint())
	case dataKind == reflect.Float32:
		f := dataVal.Float()
		if f < 0 && !d.config.WeaklyTypedInput {
			return fmt.Errorf("cannot parse '%s', %f overflows uint",
				name, f)
		}
		val.SetUint(uint64(f))
	case dataKind == reflect.Bool && d.config.WeaklyTypedInput:
		if dataVal.Bool() {
			val.SetUint(1)
		} else {
			val.SetUint(0)
		}
	case dataKind == reflect.String && d.config.WeaklyTypedInput:
		i, err := strconv.ParseUint(dataVal.String(), 0, val.Type().Bits())
		if err == nil {
			val.SetUint(i)
		} else {
			return fmt.Errorf("cannot parse '%s' as uint: %s", name, err)
		}
	default:
		return fmt.Errorf(
			"'%s' expected type '%s', got unconvertible type '%s'",
			name, val.Type(), dataVal.Type())
	}

	return nil
}

func (d *Decoder) decodeBool(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	dataKind := getKind(dataVal)

	switch {
	case dataKind == reflect.Bool:
		val.SetBool(dataVal.Bool())
	case dataKind == reflect.Int && d.config.WeaklyTypedInput:
		val.SetBool(dataVal.Int() != 0)
	case dataKind == reflect.Uint && d.config.WeaklyTypedInput:
		val.SetBool(dataVal.Uint() != 0)
	case dataKind == reflect.Float32 && d.config.WeaklyTypedInput:
		val.SetBool(dataVal.Float() != 0)
	case dataKind == reflect.String && d.config.WeaklyTypedInput:
		b, err := strconv.ParseBool(dataVal.String())
		if err == nil {
			val.SetBool(b)
		} else if dataVal.String() == "" {
			val.SetBool(false)
		} else {
			return fmt.Errorf("cannot parse '%s' as bool: %s", name, err)
		}
	default:
		return fmt.Errorf(
			"'%s' expected type '%s', got unconvertible type '%s'",
			name, val.Type(), dataVal.Type())
	}

	return nil
}

func (d *Decoder) decodeFloat(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	dataKind := getKind(dataVal)
	dataType := dataVal.Type()

	switch {
	case dataKind == reflect.Int:
		val.SetFloat(float64(dataVal.Int()))
	case dataKind == reflect.Uint:
		val.SetFloat(float64(dataVal.Uint()))
	case dataKind == reflect.Float32:
		val.SetFloat(dataVal.Float())
	case dataKind == reflect.Bool && d.config.WeaklyTypedInput:
		if dataVal.Bool() {
			val.SetFloat(1)
		} else {
			val.SetFloat(0)
		}
	case dataKind == reflect.String && d.config.WeaklyTypedInput:
		f, err := strconv.ParseFloat(dataVal.String(), val.Type().Bits())
		if err == nil {
			val.SetFloat(f)
		} else {
			return fmt.Errorf("cannot parse '%s' as float: %s", name, err)
		}
	case dataType.PkgPath() == "encoding/json" && dataType.Name() == "Number":
		jn := data.(json.Number)
		i, err := jn.Float64()
		if err != nil {
			return fmt.Errorf(
				"error decoding json.Number into %s: %s", name, err)
		}
		val.SetFloat(i)
	default:
		return fmt.Errorf(
			"'%s' expected type '%s', got unconvertible type '%s'",
			name, val.Type(), dataVal.Type())
	}

	return nil
}

func (d *Decoder) decodeMap(name string, data interface{}, val reflect.Value) error {
	valType := val.Type()
	valKeyType := valType.Key()
	valElemType := valType.Elem()

	// By default we overwrite keys in the current map
	valMap := val

	// If the map is nil or we're purposely zeroing fields, make a new map
	if valMap.IsNil() || d.config.ZeroFields {
		// Make a new map to hold our result
		mapType := reflect.MapOf(valKeyType, valElemType)
		valMap = reflect.MakeMap(mapType)
	}

	// Check input type and based on the input type jump to the proper func
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	switch dataVal.Kind() {
	case reflect.Map:
		return d.decodeMapFromMap(name, dataVal, val, valMap)

	case reflect.Struct:
		return d.decodeMapFromStruct(name, dataVal, val, valMap)

	case reflect.Array, reflect.Slice:
		if d.config.WeaklyTypedInput {
			return d.decodeMapFromSlice(name, dataVal, val, valMap)
		}

		fallthrough

	default:
		return fmt.Errorf("'%s' expected a map, got '%s'", name, dataVal.Kind())
	}
}

func (d *Decoder) decodeMapFromSlice(name string, dataVal reflect.Value, val reflect.Value, valMap reflect.Value) error {
	// Special case for BC reasons (covered by tests)
	if dataVal.Len() == 0 {
		val.Set(valMap)
		return nil
	}

	for i := 0; i < dataVal.Len(); i++ {
		err := d.decode(
			fmt.Sprintf("%s[%d]", name, i),
			dataVal.Index(i).Interface(), val)
		if err != nil {
			return err
		}
	}

	return nil
}

func (d *Decoder) decodeMapFromMap(name string, dataVal reflect.Value, val reflect.Value, valMap reflect.Value) error {
	valType := val.Type()
	valKeyType := valType.Key()
	valElemType := valType.Elem()

	// Accumulate errors
	errors := make([]string, 0)

	// If the input data is empty, then we just match what the input data is.
	if dataVal.Len() == 0 {
		if dataVal.IsNil() {
			if !val.IsNil() {
				val.Set(dataVal)
			}
		} else {
			// Set to empty allocated value
			val.Set(valMap)
		}

		return nil
	}

	for _, k := range dataVal.MapKeys() {
		fieldName := fmt.Sprintf("%s[%s]", name, k)

		// First decode the key into the proper type
		currentKey := reflect.Indirect(reflect.New(valKeyType))
		if err := d.decode(fieldName, k.Interface(), currentKey); err != nil {
			errors = appendErrors(errors, err)
			continue
		}

		// Next decode the data into the proper type
		v := dataVal.MapIndex(k).Interface()
		currentVal := reflect.Indirect(reflect.New(valElemType))
		if err := d.decode(fieldName, v, currentVal); err != nil {
			errors = appendErrors(errors, err)
			continue
		}

		valMap.SetMapIndex(currentKey, currentVal)
	}

	// Set the built up map to the value
	val.Set(valMap)

	// If we had errors, return those
	if len(errors) > 0 {
		return &Error{errors}
	}

	return nil
}

func (d *Decoder) decodeMapFromStruct(name string, dataVal reflect.Value, val reflect.Value, valMap reflect.Value) error {
	typ := dataVal.Type()
	for i := 0; i < typ.NumField(); i++ {
		// Get the StructField first since this is a cheap operation. If the
		// field is unexported, then ignore it.
		f := typ.Field(i)
		if f.PkgPath != "" {
			continue
		}

		// Next get the actual value of this field and verify it is assignable
		// to the map value.
		v := dataVal.Field(i)
		if !v.Type().AssignableTo(valMap.Type().Elem()) {
			return fmt.Errorf("cannot assign type '%s' to map value field of type '%s'", v.Type(), valMap.Type().Elem())
		}

		tagValue := f.Tag.Get(d.config.TagName)
		tagParts := strings.Split(tagValue, ",")

		// Determine the name of the key in the map
		keyName := f.Name
		if tagParts[0] != "" {
			if tagParts[0] == "-" {
				continue
			}
			keyName = tagParts[0]
		}

		// If "squash" is specified in the tag, we squash the field down.
		squash := false
		for _, tag := range tagParts[1:] {
			if tag == "squash" {
				squash = true
				break
			}
		}
		if squash && v.Kind() != reflect.Struct {
			return fmt.Errorf("cannot squash non-struct type '%s'", v.Type())
		}

		switch v.Kind() {
		// this is an embedded struct, so handle it differently
		case reflect.Struct:
			x := reflect.New(v.Type())
			x.Elem().Set(v)

			vType := valMap.Type()
			vKeyType := vType.Key()
			vElemType := vType.Elem()
			mType := reflect.MapOf(vKeyType, vElemType)
			vMap := reflect.MakeMap(mType)

			err := d.decode(keyName, x.Interface(), vMap)
			if err != nil {
				return err
			}

			if squash {
				for _, k := range vMap.MapKeys() {
					valMap.SetMapIndex(k, vMap.MapIndex(k))
				}
			} else {
				valMap.SetMapIndex(reflect.ValueOf(keyName), vMap)
			}

		default:
			valMap.SetMapIndex(reflect.ValueOf(keyName), v)
		}
	}

	if val.CanAddr() {
		val.Set(valMap)
	}

	return nil
}

func (d *Decoder) decodePtr(name string, data interface{}, val reflect.Value) error {
	// If the input data is nil, then we want to just set the output
	// pointer to be nil as well.
	isNil := data == nil
	if !isNil {
		switch v := reflect.Indirect(reflect.ValueOf(data)); v.Kind() {
		case reflect.Chan,
			reflect.Func,
			reflect.Interface,
			reflect.Map,
			reflect.Ptr,
			reflect.Slice:
			isNil = v.IsNil()
		}
	}
	if isNil {
		if !val.IsNil() && val.CanSet() {
			nilValue := reflect.New(val.Type()).Elem()
			val.Set(nilValue)
		}

		return nil
	}

	// Create an element of the concrete (non pointer) type and decode
	// into that. Then set the value of the pointer to this type.
	valType := val.Type()
	valElemType := valType.Elem()
	if val.CanSet() {
		realVal := val
		if realVal.IsNil() || d.config.ZeroFields {
			realVal = reflect.New(valElemType)
		}

		if err := d.decode(name, data, reflect.Indirect(realVal)); err != nil {
			return err
		}

		val.Set(realVal)
	} else {
		if err := d.decode(name, data, reflect.Indirect(val)); err != nil {
			return err
		}
	}
	return nil
}

func (d *Decoder) decodeFunc(name string, data interface{}, val reflect.Value) error {
	// Create an element of the concrete (non pointer) type and decode
	// into that. Then set the value of the pointer to this type.
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	if val.Type() != dataVal.Type() {
		return fmt.Errorf(
			"'%s' expected type '%s', got unconvertible type '%s'",
			name, val.Type(), dataVal.Type())
	}
	val.Set(dataVal)
	return nil
}

func (d *Decoder) decodeSlice(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	dataValKind := dataVal.Kind()
	valType := val.Type()
	valElemType := valType.Elem()
	sliceType := reflect.SliceOf(valElemType)

	valSlice := val
	if valSlice.IsNil() || d.config.ZeroFields {
		if d.config.WeaklyTypedInput {
			switch {
			// Slice and array we use the normal logic
			case dataValKind == reflect.Slice, dataValKind == reflect.Array:
				break

			// Empty maps turn into empty slices
			case dataValKind == reflect.Map:
				if dataVal.Len() == 0 {
					val.Set(reflect.MakeSlice(sliceType, 0, 0))
					return nil
				}
				// Create slice of maps of other sizes
				return d.decodeSlice(name, []interface{}{data}, val)

			case dataValKind == reflect.String && valElemType.Kind() == reflect.Uint8:
				return d.decodeSlice(name, []byte(dataVal.String()), val)

			// All other types we try to convert to the slice type
			// and "lift" it into it. i.e. a string becomes a string slice.
			default:
				// Just re-try this function with data as a slice.
				return d.decodeSlice(name, []interface{}{data}, val)
			}
		}

		// Check input type
		if dataValKind != reflect.Array && dataValKind != reflect.Slice {
			return fmt.Errorf(
				"'%s': source data must be an array or slice, got %s", name, dataValKind)

		}

		// If the input value is empty, then don't allocate since non-nil != nil
		if dataVal.Len() == 0 {
			return nil
		}

		// Make a new slice to hold our result, same size as the original data.
		valSlice = reflect.MakeSlice(sliceType, dataVal.Len(), dataVal.Len())
	}

	// Accumulate any errors
	errors := make([]string, 0)

	for i := 0; i < dataVal.Len(); i++ {
		currentData := dataVal.Index(i).Interface()
		for valSlice.Len() <= i {
			valSlice = reflect.Append(valSlice, reflect.Zero(valElemType))
		}
		currentField := valSlice.Index(i)

		fieldName := fmt.Sprintf("%s[%d]", name, i)
		if err := d.decode(fieldName, currentData, currentField); err != nil {
			errors = appendErrors(errors, err)
		}
	}

	// Finally, set the value to the slice we built up
	val.Set(valSlice)

	// If there were errors, we return those
	if len(errors) > 0 {
		return &Error{errors}
	}

	return nil
}

func (d *Decoder) decodeArray(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))
	dataValKind := dataVal.Kind()
	valType := val.Type()
	valElemType := valType.Elem()
	arrayType := reflect.ArrayOf(valType.Len(), valElemType)

	valArray := val

	if valArray.Interface() == reflect.Zero(valArray.Type()).Interface() || d.config.ZeroFields {
		// Check input type
		if dataValKind != reflect.Array && dataValKind != reflect.Slice {
			if d.config.WeaklyTypedInput {
				switch {
				// Empty maps turn into empty arrays
				case dataValKind == reflect.Map:
					if dataVal.Len() == 0 {
						val.Set(reflect.Zero(arrayType))
						return nil
					}

				// All other types we try to convert to the array type
				// and "lift" it into it. i.e. a string becomes a string array.
				default:
					// Just re-try this function with data as a slice.
					return d.decodeArray(name, []interface{}{data}, val)
				}
			}

			return fmt.Errorf(
				"'%s': source data must be an array or slice, got %s", name, dataValKind)

		}
		if dataVal.Len() > arrayType.Len() {
			return fmt.Errorf(
				"'%s': expected source data to have length less or equal to %d, got %d", name, arrayType.Len(), dataVal.Len())

		}

		// Make a new array to hold our result, same size as the original data.
		valArray = reflect.New(arrayType).Elem()
	}

	// Accumulate any errors
	errors := make([]string, 0)

	for i := 0; i < dataVal.Len(); i++ {
		currentData := dataVal.Index(i).Interface()
		currentField := valArray.Index(i)

		fieldName := fmt.Sprintf("%s[%d]", name, i)
		if err := d.decode(fieldName, currentData, currentField); err != nil {
			errors = appendErrors(errors, err)
		}
	}

	// Finally, set the value to the array we built up
	val.Set(valArray)

	// If there were errors, we return those
	if len(errors) > 0 {
		return &Error{errors}
	}

	return nil
}

func (d *Decoder) decodeStruct(name string, data interface{}, val reflect.Value) error {
	dataVal := reflect.Indirect(reflect.ValueOf(data))

	// If the type of the value to write to and the data match directly,
	// then we just set it directly instead of recursing into the structure.
	if dataVal.Type() == val.Type() {
		val.Set(dataVal)
		return nil
	}

	dataValKind := dataVal.Kind()
	switch dataValKind {
	case reflect.Map:
		return d.decodeStructFromMap(name, dataVal, val)

	case reflect.Struct:
		// Not the most efficient way to do this but we can optimize later if
		// we want to. To convert from struct to struct we go to map first
		// as an intermediary.
		m := make(map[string]interface{})
		mval := reflect.Indirect(reflect.ValueOf(&m))
		if err := d.decodeMapFromStruct(name, dataVal, mval, mval); err != nil {
			return err
		}

		result := d.decodeStructFromMap(name, mval, val)
		return result

	default:
		return fmt.Errorf("'%s' expected a map, got '%s'", name, dataVal.Kind())
	}
}

func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) error {
	dataValType := dataVal.Type()
	if kind := dataValType.Key().Kind(); kind != reflect.String && kind != reflect.Interface {
		return fmt.Errorf(
			"'%s' needs a map with string keys, has '%s' keys",
			name, dataValType.Key().Kind())
	}

	dataValKeys := make(map[reflect.Value]struct{})
	dataValKeysUnused := make(map[interface{}]struct{})
	for _, dataValKey := range dataVal.MapKeys() {
		dataValKeys[dataValKey] = struct{}{}
		dataValKeysUnused[dataValKey.Interface()] = struct{}{}
	}

	errors := make([]string, 0)

	// This slice will keep track of all the structs we'll be decoding.
	// There can be more than one struct if there are embedded structs
	// that are squashed.
	structs := make([]reflect.Value, 1, 5)
	structs[0] = val

	// Compile the list of all the fields that we're going to be decoding
	// from all the structs.
	type field struct {
		field reflect.StructField
		val   reflect.Value
	}
	fields := []field{}
	for len(structs) > 0 {
		structVal := structs[0]
		structs = structs[1:]

		structType := structVal.Type()

		for i := 0; i < structType.NumField(); i++ {
			fieldType := structType.Field(i)
			fieldKind := fieldType.Type.Kind()

			// If "squash" is specified in the tag, we squash the field down.
			squash := false
			tagParts := strings.Split(fieldType.Tag.Get(d.config.TagName), ",")
			for _, tag := range tagParts[1:] {
				if tag == "squash" {
					squash = true
					break
				}
			}

			if squash {
				if fieldKind != reflect.Struct {
					errors = appendErrors(errors,
						fmt.Errorf("%s: unsupported type for squash: %s", fieldType.Name, fieldKind))
				} else {
					structs = append(structs, structVal.FieldByName(fieldType.Name))
				}
				continue
			}

			// Normal struct field, store it away
			fields = append(fields, field{fieldType, structVal.Field(i)})
		}
	}

	// for fieldType, field := range fields {
	for _, f := range fields {
		field, fieldValue := f.field, f.val
		fieldName := field.Name

		tagValue := field.Tag.Get(d.config.TagName)
		tagValue = strings.SplitN(tagValue, ",", 2)[0]
		if tagValue != "" {
			fieldName = tagValue
		}

		rawMapKey := reflect.ValueOf(fieldName)
		rawMapVal := dataVal.MapIndex(rawMapKey)
		if !rawMapVal.IsValid() {
			// Do a slower search by iterating over each key and
			// doing case-insensitive search.
			for dataValKey := range dataValKeys {
				mK, ok := dataValKey.Interface().(string)
				if !ok {
					// Not a string key
					continue
				}

				if strings.EqualFold(mK, fieldName) {
					rawMapKey = dataValKey
					rawMapVal = dataVal.MapIndex(dataValKey)
					break
				}
			}

			if !rawMapVal.IsValid() {
				// There was no matching key in the map for the value in
				// the struct. Just ignore.
				continue
			}
		}

		// Delete the key we're using from the unused map so we stop tracking
		delete(dataValKeysUnused, rawMapKey.Interface())

		if !fieldValue.IsValid() {
			// This should never happen
			panic("field is not valid")
		}

		// If we can't set the field, then it is unexported or something,
		// and we just continue onwards.
		if !fieldValue.CanSet() {
			continue
		}

		// If the name is empty string, then we're at the root, and we
		// don't dot-join the fields.
		if name != "" {
			fieldName = fmt.Sprintf("%s.%s", name, fieldName)
		}

		if err := d.decode(fieldName, rawMapVal.Interface(), fieldValue); err != nil {
			errors = appendErrors(errors, err)
		}
	}

	if d.config.ErrorUnused && len(dataValKeysUnused) > 0 {
		keys := make([]string, 0, len(dataValKeysUnused))
		for rawKey := range dataValKeysUnused {
			keys = append(keys, rawKey.(string))
		}
		sort.Strings(keys)

		err := fmt.Errorf("'%s' has invalid keys: %s", name, strings.Join(keys, ", "))
		errors = appendErrors(errors, err)
	}

	if len(errors) > 0 {
		return &Error{errors}
	}

	// Add the unused keys to the list of unused keys if we're tracking metadata
	if d.config.Metadata != nil {
		for rawKey := range dataValKeysUnused {
			key := rawKey.(string)
			if name != "" {
				key = fmt.Sprintf("%s.%s", name, key)
			}

			d.config.Metadata.Unused = append(d.config.Metadata.Unused, key)
		}
	}

	return nil
}

func getKind(val reflect.Value) reflect.Kind {
	kind := val.Kind()

	switch {
	case kind >= reflect.Int && kind <= reflect.Int64:
		return reflect.Int
	case kind >= reflect.Uint && kind <= reflect.Uint64:
		return reflect.Uint
	case kind >= reflect.Float32 && kind <= reflect.Float64:
		return reflect.Float32
	default:
		return kind
	}
}