summaryrefslogtreecommitdiff
path: root/src/mscorlib/src/System/Decimal.cs
blob: ce59a99334fc38ba45591609bccf8b6918ebf28b (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
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
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.


using System;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
using System.Runtime.ConstrainedExecution;
using System.Runtime.Versioning;
using System.Runtime.Serialization;
using System.Diagnostics.Contracts;

namespace System
{
    // Implements the Decimal data type. The Decimal data type can
    // represent values ranging from -79,228,162,514,264,337,593,543,950,335 to
    // 79,228,162,514,264,337,593,543,950,335 with 28 significant digits. The
    // Decimal data type is ideally suited to financial calculations that
    // require a large number of significant digits and no round-off errors.
    //
    // The finite set of values of type Decimal are of the form m
    // / 10e, where m is an integer such that
    // -296 <; m <; 296, and e is an integer
    // between 0 and 28 inclusive.
    //
    // Contrary to the float and double data types, decimal
    // fractional numbers such as 0.1 can be represented exactly in the
    // Decimal representation. In the float and double
    // representations, such numbers are often infinite fractions, making those
    // representations more prone to round-off errors.
    //
    // The Decimal class implements widening conversions from the
    // ubyte, char, short, int, and long types
    // to Decimal. These widening conversions never loose any information
    // and never throw exceptions. The Decimal class also implements
    // narrowing conversions from Decimal to ubyte, char,
    // short, int, and long. These narrowing conversions round
    // the Decimal value towards zero to the nearest integer, and then
    // converts that integer to the destination type. An OverflowException
    // is thrown if the result is not within the range of the destination type.
    //
    // The Decimal class provides a widening conversion from
    // Currency to Decimal. This widening conversion never loses any
    // information and never throws exceptions. The Currency class provides
    // a narrowing conversion from Decimal to Currency. This
    // narrowing conversion rounds the Decimal to four decimals and then
    // converts that number to a Currency. An OverflowException
    // is thrown if the result is not within the range of the Currency type.
    //
    // The Decimal class provides narrowing conversions to and from the
    // float and double types. A conversion from Decimal to
    // float or double may loose precision, but will not loose
    // information about the overall magnitude of the numeric value, and will never
    // throw an exception. A conversion from float or double to
    // Decimal throws an OverflowException if the value is not within
    // the range of the Decimal type.
    [StructLayout(LayoutKind.Sequential)]
    [Serializable]
    [System.Runtime.Versioning.NonVersionable] // This only applies to field layout
    public struct Decimal : IFormattable, IComparable, IConvertible, IComparable<Decimal>, IEquatable<Decimal>, IDeserializationCallback
    {
        // Sign mask for the flags field. A value of zero in this bit indicates a
        // positive Decimal value, and a value of one in this bit indicates a
        // negative Decimal value.
        // 
        // Look at OleAut's DECIMAL_NEG constant to check for negative values
        // in native code.
        private const int SignMask = unchecked((int)0x80000000);
        private const byte DECIMAL_NEG = 0x80;
        private const byte DECIMAL_ADD = 0x00;

        // Scale mask for the flags field. This byte in the flags field contains
        // the power of 10 to divide the Decimal value by. The scale byte must
        // contain a value between 0 and 28 inclusive.
        private const int ScaleMask = 0x00FF0000;

        // Number of bits scale is shifted by.
        private const int ScaleShift = 16;

        // The maximum power of 10 that a 32 bit integer can store
        private const Int32 MaxInt32Scale = 9;

        // Fast access for 10^n where n is 0-9        
        private static UInt32[] Powers10 = new UInt32[] {
            1,
            10,
            100,
            1000,
            10000,
            100000,
            1000000,
            10000000,
            100000000,
            1000000000
        };

        // Constant representing the Decimal value 0.
        public const Decimal Zero = 0m;

        // Constant representing the Decimal value 1.
        public const Decimal One = 1m;

        // Constant representing the Decimal value -1.
        public const Decimal MinusOne = -1m;

        // Constant representing the largest possible Decimal value. The value of
        // this constant is 79,228,162,514,264,337,593,543,950,335.
        public const Decimal MaxValue = 79228162514264337593543950335m;

        // Constant representing the smallest possible Decimal value. The value of
        // this constant is -79,228,162,514,264,337,593,543,950,335.
        public const Decimal MinValue = -79228162514264337593543950335m;


        // Constant representing the negative number that is the closest possible
        // Decimal value to -0m.
        private const Decimal NearNegativeZero = -0.000000000000000000000000001m;

        // Constant representing the positive number that is the closest possible
        // Decimal value to +0m.
        private const Decimal NearPositiveZero = +0.000000000000000000000000001m;

        // The lo, mid, hi, and flags fields contain the representation of the
        // Decimal value. The lo, mid, and hi fields contain the 96-bit integer
        // part of the Decimal. Bits 0-15 (the lower word) of the flags field are
        // unused and must be zero; bits 16-23 contain must contain a value between
        // 0 and 28, indicating the power of 10 to divide the 96-bit integer part
        // by to produce the Decimal value; bits 24-30 are unused and must be zero;
        // and finally bit 31 indicates the sign of the Decimal value, 0 meaning
        // positive and 1 meaning negative.
        //
        // NOTE: Do not change the order in which these fields are declared. The
        // native methods in this class rely on this particular order.
        private int flags;
        private int hi;
        private int lo;
        private int mid;


        // Constructs a zero Decimal.
        //public Decimal() {
        //    lo = 0;
        //    mid = 0;
        //    hi = 0;
        //    flags = 0;
        //}

        // Constructs a Decimal from an integer value.
        //
        public Decimal(int value)
        {
            //  JIT today can't inline methods that contains "starg" opcode.
            //  For more details, see DevDiv Bugs 81184: x86 JIT CQ: Removing the inline striction of "starg".
            int value_copy = value;
            if (value_copy >= 0)
            {
                flags = 0;
            }
            else
            {
                flags = SignMask;
                value_copy = -value_copy;
            }
            lo = value_copy;
            mid = 0;
            hi = 0;
        }

        // Constructs a Decimal from an unsigned integer value.
        //
        [CLSCompliant(false)]
        public Decimal(uint value)
        {
            flags = 0;
            lo = (int)value;
            mid = 0;
            hi = 0;
        }

        // Constructs a Decimal from a long value.
        //
        public Decimal(long value)
        {
            //  JIT today can't inline methods that contains "starg" opcode.
            //  For more details, see DevDiv Bugs 81184: x86 JIT CQ: Removing the inline striction of "starg".
            long value_copy = value;
            if (value_copy >= 0)
            {
                flags = 0;
            }
            else
            {
                flags = SignMask;
                value_copy = -value_copy;
            }
            lo = (int)value_copy;
            mid = (int)(value_copy >> 32);
            hi = 0;
        }

        // Constructs a Decimal from an unsigned long value.
        //
        [CLSCompliant(false)]
        public Decimal(ulong value)
        {
            flags = 0;
            lo = (int)value;
            mid = (int)(value >> 32);
            hi = 0;
        }

        // Constructs a Decimal from a float value.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        public extern Decimal(float value);

        // Constructs a Decimal from a double value.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        public extern Decimal(double value);

        // Constructs a Decimal from a Currency value.
        //
        internal Decimal(Currency value)
        {
            this = Currency.ToDecimal(value);
        }

        // Don't remove these 2 methods below. They are required by the fx when the are dealing with Currency in their
        // databases
        public static long ToOACurrency(Decimal value)
        {
            return new Currency(value).ToOACurrency();
        }

        public static Decimal FromOACurrency(long cy)
        {
            return Currency.ToDecimal(Currency.FromOACurrency(cy));
        }


        // Constructs a Decimal from an integer array containing a binary
        // representation. The bits argument must be a non-null integer
        // array with four elements. bits[0], bits[1], and
        // bits[2] contain the low, middle, and high 32 bits of the 96-bit
        // integer part of the Decimal. bits[3] contains the scale factor
        // and sign of the Decimal: bits 0-15 (the lower word) are unused and must
        // be zero; bits 16-23 must contain a value between 0 and 28, indicating
        // the power of 10 to divide the 96-bit integer part by to produce the
        // Decimal value; bits 24-30 are unused and must be zero; and finally bit
        // 31 indicates the sign of the Decimal value, 0 meaning positive and 1
        // meaning negative.
        //
        // Note that there are several possible binary representations for the
        // same numeric value. For example, the value 1 can be represented as {1,
        // 0, 0, 0} (integer value 1 with a scale factor of 0) and equally well as
        // {1000, 0, 0, 0x30000} (integer value 1000 with a scale factor of 3).
        // The possible binary representations of a particular value are all
        // equally valid, and all are numerically equivalent.
        //
        public Decimal(int[] bits)
        {
            lo = 0;
            mid = 0;
            hi = 0;
            flags = 0;
            SetBits(bits);
        }

        private void SetBits(int[] bits)
        {
            if (bits == null)
                throw new ArgumentNullException(nameof(bits));
            Contract.EndContractBlock();
            if (bits.Length == 4)
            {
                int f = bits[3];
                if ((f & ~(SignMask | ScaleMask)) == 0 && (f & ScaleMask) <= (28 << 16))
                {
                    lo = bits[0];
                    mid = bits[1];
                    hi = bits[2];
                    flags = f;
                    return;
                }
            }
            throw new ArgumentException(SR.Arg_DecBitCtor);
        }

        // Constructs a Decimal from its constituent parts.
        // 
        public Decimal(int lo, int mid, int hi, bool isNegative, byte scale)
        {
            if (scale > 28)
                throw new ArgumentOutOfRangeException(nameof(scale), SR.ArgumentOutOfRange_DecimalScale);
            Contract.EndContractBlock();
            this.lo = lo;
            this.mid = mid;
            this.hi = hi;
            flags = ((int)scale) << 16;
            if (isNegative)
                flags |= SignMask;
        }

        [OnSerializing]
        private void OnSerializing(StreamingContext ctx)
        {
            // OnSerializing is called before serialization of an object
            try
            {
                SetBits(GetBits(this));
            }
            catch (ArgumentException e)
            {
                throw new SerializationException(SR.Overflow_Decimal, e);
            }
        }

        void IDeserializationCallback.OnDeserialization(Object sender)
        {
            // OnDeserialization is called after each instance of this class is deserialized.
            // This callback method performs decimal validation after being deserialized.
            try
            {
                SetBits(GetBits(this));
            }
            catch (ArgumentException e)
            {
                throw new SerializationException(SR.Overflow_Decimal, e);
            }
        }

        // Constructs a Decimal from its constituent parts.
        private Decimal(int lo, int mid, int hi, int flags)
        {
            if ((flags & ~(SignMask | ScaleMask)) == 0 && (flags & ScaleMask) <= (28 << 16))
            {
                this.lo = lo;
                this.mid = mid;
                this.hi = hi;
                this.flags = flags;
                return;
            }
            throw new ArgumentException(SR.Arg_DecBitCtor);
        }

        // Returns the absolute value of the given Decimal. If d is
        // positive, the result is d. If d is negative, the result
        // is -d.
        //
        internal static Decimal Abs(Decimal d)
        {
            return new Decimal(d.lo, d.mid, d.hi, d.flags & ~SignMask);
        }

        // Adds two Decimal values.
        //
        public static Decimal Add(Decimal d1, Decimal d2)
        {
            FCallAddSub(ref d1, ref d2, DECIMAL_ADD);
            return d1;
        }

        // FCallAddSub adds or subtracts two decimal values.  On return, d1 contains the result
        // of the operation.  Passing in DECIMAL_ADD or DECIMAL_NEG for bSign indicates
        // addition or subtraction, respectively.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern void FCallAddSub(ref Decimal d1, ref Decimal d2, byte bSign);

        // Rounds a Decimal to an integer value. The Decimal argument is rounded
        // towards positive infinity.
        public static Decimal Ceiling(Decimal d)
        {
            return (-(Decimal.Floor(-d)));
        }

        // Compares two Decimal values, returning an integer that indicates their
        // relationship.
        //
        public static int Compare(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2);
        }

        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern int FCallCompare(ref Decimal d1, ref Decimal d2);

        // Compares this object to another object, returning an integer that
        // indicates the relationship. 
        // Returns a value less than zero if this  object
        // null is considered to be less than any instance.
        // If object is not of type Decimal, this method throws an ArgumentException.
        // 
        public int CompareTo(Object value)
        {
            if (value == null)
                return 1;
            if (!(value is Decimal))
                throw new ArgumentException(SR.Arg_MustBeDecimal);

            Decimal other = (Decimal)value;
            return FCallCompare(ref this, ref other);
        }

        public int CompareTo(Decimal value)
        {
            return FCallCompare(ref this, ref value);
        }

        // Divides two Decimal values.
        //
        public static Decimal Divide(Decimal d1, Decimal d2)
        {
            FCallDivide(ref d1, ref d2);
            return d1;
        }

        // FCallDivide divides two decimal values.  On return, d1 contains the result
        // of the operation.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern void FCallDivide(ref Decimal d1, ref Decimal d2);


        // Checks if this Decimal is equal to a given object. Returns true
        // if the given object is a boxed Decimal and its value is equal to the
        // value of this Decimal. Returns false otherwise.
        //
        public override bool Equals(Object value)
        {
            if (value is Decimal)
            {
                Decimal other = (Decimal)value;
                return FCallCompare(ref this, ref other) == 0;
            }
            return false;
        }

        public bool Equals(Decimal value)
        {
            return FCallCompare(ref this, ref value) == 0;
        }

        // Returns the hash code for this Decimal.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        public extern override int GetHashCode();

        // Compares two Decimal values for equality. Returns true if the two
        // Decimal values are equal, or false if they are not equal.
        //
        public static bool Equals(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) == 0;
        }

        // Rounds a Decimal to an integer value. The Decimal argument is rounded
        // towards negative infinity.
        //
        public static Decimal Floor(Decimal d)
        {
            FCallFloor(ref d);
            return d;
        }

        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern void FCallFloor(ref Decimal d);

        // Converts this Decimal to a string. The resulting string consists of an
        // optional minus sign ("-") followed to a sequence of digits ("0" - "9"),
        // optionally followed by a decimal point (".") and another sequence of
        // digits.
        //
        public override String ToString()
        {
            Contract.Ensures(Contract.Result<String>() != null);
            return Number.FormatDecimal(this, null, NumberFormatInfo.CurrentInfo);
        }

        public String ToString(String format)
        {
            Contract.Ensures(Contract.Result<String>() != null);
            return Number.FormatDecimal(this, format, NumberFormatInfo.CurrentInfo);
        }

        public String ToString(IFormatProvider provider)
        {
            Contract.Ensures(Contract.Result<String>() != null);
            return Number.FormatDecimal(this, null, NumberFormatInfo.GetInstance(provider));
        }

        public String ToString(String format, IFormatProvider provider)
        {
            Contract.Ensures(Contract.Result<String>() != null);
            return Number.FormatDecimal(this, format, NumberFormatInfo.GetInstance(provider));
        }


        // Converts a string to a Decimal. The string must consist of an optional
        // minus sign ("-") followed by a sequence of digits ("0" - "9"). The
        // sequence of digits may optionally contain a single decimal point (".")
        // character. Leading and trailing whitespace characters are allowed.
        // Parse also allows a currency symbol, a trailing negative sign, and
        // parentheses in the number.
        //
        public static Decimal Parse(String s)
        {
            return Number.ParseDecimal(s, NumberStyles.Number, NumberFormatInfo.CurrentInfo);
        }

        public static Decimal Parse(String s, NumberStyles style)
        {
            NumberFormatInfo.ValidateParseStyleFloatingPoint(style);
            return Number.ParseDecimal(s, style, NumberFormatInfo.CurrentInfo);
        }

        public static Decimal Parse(String s, IFormatProvider provider)
        {
            return Number.ParseDecimal(s, NumberStyles.Number, NumberFormatInfo.GetInstance(provider));
        }

        public static Decimal Parse(String s, NumberStyles style, IFormatProvider provider)
        {
            NumberFormatInfo.ValidateParseStyleFloatingPoint(style);
            return Number.ParseDecimal(s, style, NumberFormatInfo.GetInstance(provider));
        }

        public static Boolean TryParse(String s, out Decimal result)
        {
            return Number.TryParseDecimal(s, NumberStyles.Number, NumberFormatInfo.CurrentInfo, out result);
        }

        public static Boolean TryParse(String s, NumberStyles style, IFormatProvider provider, out Decimal result)
        {
            NumberFormatInfo.ValidateParseStyleFloatingPoint(style);
            return Number.TryParseDecimal(s, style, NumberFormatInfo.GetInstance(provider), out result);
        }

        // Returns a binary representation of a Decimal. The return value is an
        // integer array with four elements. Elements 0, 1, and 2 contain the low,
        // middle, and high 32 bits of the 96-bit integer part of the Decimal.
        // Element 3 contains the scale factor and sign of the Decimal: bits 0-15
        // (the lower word) are unused; bits 16-23 contain a value between 0 and
        // 28, indicating the power of 10 to divide the 96-bit integer part by to
        // produce the Decimal value; bits 24-30 are unused; and finally bit 31
        // indicates the sign of the Decimal value, 0 meaning positive and 1
        // meaning negative.
        //
        public static int[] GetBits(Decimal d)
        {
            return new int[] { d.lo, d.mid, d.hi, d.flags };
        }

        internal static void GetBytes(Decimal d, byte[] buffer)
        {
            Contract.Requires((buffer != null && buffer.Length >= 16), "[GetBytes]buffer != null && buffer.Length >= 16");
            buffer[0] = (byte)d.lo;
            buffer[1] = (byte)(d.lo >> 8);
            buffer[2] = (byte)(d.lo >> 16);
            buffer[3] = (byte)(d.lo >> 24);

            buffer[4] = (byte)d.mid;
            buffer[5] = (byte)(d.mid >> 8);
            buffer[6] = (byte)(d.mid >> 16);
            buffer[7] = (byte)(d.mid >> 24);

            buffer[8] = (byte)d.hi;
            buffer[9] = (byte)(d.hi >> 8);
            buffer[10] = (byte)(d.hi >> 16);
            buffer[11] = (byte)(d.hi >> 24);

            buffer[12] = (byte)d.flags;
            buffer[13] = (byte)(d.flags >> 8);
            buffer[14] = (byte)(d.flags >> 16);
            buffer[15] = (byte)(d.flags >> 24);
        }

        internal static decimal ToDecimal(byte[] buffer)
        {
            Contract.Requires((buffer != null && buffer.Length >= 16), "[ToDecimal]buffer != null && buffer.Length >= 16");
            int lo = ((int)buffer[0]) | ((int)buffer[1] << 8) | ((int)buffer[2] << 16) | ((int)buffer[3] << 24);
            int mid = ((int)buffer[4]) | ((int)buffer[5] << 8) | ((int)buffer[6] << 16) | ((int)buffer[7] << 24);
            int hi = ((int)buffer[8]) | ((int)buffer[9] << 8) | ((int)buffer[10] << 16) | ((int)buffer[11] << 24);
            int flags = ((int)buffer[12]) | ((int)buffer[13] << 8) | ((int)buffer[14] << 16) | ((int)buffer[15] << 24);
            return new Decimal(lo, mid, hi, flags);
        }

        // This method does a 'raw' and 'unchecked' addition of a UInt32 to a Decimal in place. 
        // 'raw' means that it operates on the internal 96-bit unsigned integer value and 
        // ingores the sign and scale. This means that it is not equivalent to just adding
        // that number, as the sign and scale are effectively applied to the UInt32 value also.
        // 'unchecked' means that it does not fail if you overflow the 96 bit value.
        private static void InternalAddUInt32RawUnchecked(ref Decimal value, UInt32 i)
        {
            UInt32 v;
            UInt32 sum;
            v = (UInt32)value.lo;
            sum = v + i;
            value.lo = (Int32)sum;
            if (sum < v || sum < i)
            {
                v = (UInt32)value.mid;
                sum = v + 1;
                value.mid = (Int32)sum;
                if (sum < v || sum < 1)
                {
                    value.hi = (Int32)((UInt32)value.hi + 1);
                }
            }
        }

        // This method does an in-place division of a decimal by a UInt32, returning the remainder. 
        // Although it does not operate on the sign or scale, this does not result in any 
        // caveat for the result. It is equivalent to dividing by that number.
        private static UInt32 InternalDivRemUInt32(ref Decimal value, UInt32 divisor)
        {
            UInt32 remainder = 0;
            UInt64 n;
            if (value.hi != 0)
            {
                n = ((UInt32)value.hi);
                value.hi = (Int32)((UInt32)(n / divisor));
                remainder = (UInt32)(n % divisor);
            }
            if (value.mid != 0 || remainder != 0)
            {
                n = ((UInt64)remainder << 32) | (UInt32)value.mid;
                value.mid = (Int32)((UInt32)(n / divisor));
                remainder = (UInt32)(n % divisor);
            }
            if (value.lo != 0 || remainder != 0)
            {
                n = ((UInt64)remainder << 32) | (UInt32)value.lo;
                value.lo = (Int32)((UInt32)(n / divisor));
                remainder = (UInt32)(n % divisor);
            }
            return remainder;
        }

        // Does an in-place round the specified number of digits, rounding mid-point values
        // away from zero
        private static void InternalRoundFromZero(ref Decimal d, int decimalCount)
        {
            Int32 scale = (d.flags & ScaleMask) >> ScaleShift;
            Int32 scaleDifference = scale - decimalCount;
            if (scaleDifference <= 0)
            {
                return;
            }
            // Divide the value by 10^scaleDifference
            UInt32 lastRemainder;
            UInt32 lastDivisor;
            do
            {
                Int32 diffChunk = (scaleDifference > MaxInt32Scale) ? MaxInt32Scale : scaleDifference;
                lastDivisor = Powers10[diffChunk];
                lastRemainder = InternalDivRemUInt32(ref d, lastDivisor);
                scaleDifference -= diffChunk;
            } while (scaleDifference > 0);

            // Round away from zero at the mid point
            if (lastRemainder >= (lastDivisor >> 1))
            {
                InternalAddUInt32RawUnchecked(ref d, 1);
            }

            // the scale becomes the desired decimal count
            d.flags = ((decimalCount << ScaleShift) & ScaleMask) | (d.flags & SignMask);
        }

        // Returns the larger of two Decimal values.
        //
        internal static Decimal Max(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) >= 0 ? d1 : d2;
        }

        // Returns the smaller of two Decimal values.
        //
        internal static Decimal Min(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) < 0 ? d1 : d2;
        }

        public static Decimal Remainder(Decimal d1, Decimal d2)
        {
            // OleAut doesn't provide a VarDecMod.            

            // In the operation x % y the sign of y does not matter. Result will have the sign of x.
            d2.flags = (d2.flags & ~SignMask) | (d1.flags & SignMask);


            // This piece of code is to work around the fact that Dividing a decimal with 28 digits number by decimal which causes
            // causes the result to be 28 digits, can cause to be incorrectly rounded up.
            // eg. Decimal.MaxValue / 2 * Decimal.MaxValue will overflow since the division by 2 was rounded instead of being truncked.
            if (Abs(d1) < Abs(d2))
            {
                return d1;
            }
            d1 -= d2;

            if (d1 == 0)
            {
                // The sign of D1 will be wrong here. Fall through so that we still get a DivideByZeroException
                d1.flags = (d1.flags & ~SignMask) | (d2.flags & SignMask);
            }

            // Formula:  d1 - (RoundTowardsZero(d1 / d2) * d2)            
            Decimal dividedResult = Truncate(d1 / d2);
            Decimal multipliedResult = dividedResult * d2;
            Decimal result = d1 - multipliedResult;
            // See if the result has crossed 0
            if ((d1.flags & SignMask) != (result.flags & SignMask))
            {
                if (NearNegativeZero <= result && result <= NearPositiveZero)
                {
                    // Certain Remainder operations on decimals with 28 significant digits round
                    // to [+-]0.000000000000000000000000001m instead of [+-]0m during the intermediate calculations. 
                    // 'zero' results just need their sign corrected.
                    result.flags = (result.flags & ~SignMask) | (d1.flags & SignMask);
                }
                else
                {
                    // If the division rounds up because it runs out of digits, the multiplied result can end up with a larger
                    // absolute value and the result of the formula crosses 0. To correct it can add the divisor back.
                    result += d2;
                }
            }

            return result;
        }

        // Multiplies two Decimal values.
        //
        public static Decimal Multiply(Decimal d1, Decimal d2)
        {
            FCallMultiply(ref d1, ref d2);
            return d1;
        }

        // FCallMultiply multiples two decimal values.  On return, d1 contains the result
        // of the operation.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern void FCallMultiply(ref Decimal d1, ref Decimal d2);

        // Returns the negated value of the given Decimal. If d is non-zero,
        // the result is -d. If d is zero, the result is zero.
        //
        public static Decimal Negate(Decimal d)
        {
            return new Decimal(d.lo, d.mid, d.hi, d.flags ^ SignMask);
        }

        // Rounds a Decimal value to a given number of decimal places. The value
        // given by d is rounded to the number of decimal places given by
        // decimals. The decimals argument must be an integer between
        // 0 and 28 inclusive.
        //
        // By default a mid-point value is rounded to the nearest even number. If the mode is
        // passed in, it can also round away from zero.

        public static Decimal Round(Decimal d)
        {
            return Round(d, 0);
        }

        public static Decimal Round(Decimal d, int decimals)
        {
            FCallRound(ref d, decimals);
            return d;
        }

        public static Decimal Round(Decimal d, MidpointRounding mode)
        {
            return Round(d, 0, mode);
        }

        public static Decimal Round(Decimal d, int decimals, MidpointRounding mode)
        {
            if ((decimals < 0) || (decimals > 28))
                throw new ArgumentOutOfRangeException(nameof(decimals), SR.ArgumentOutOfRange_DecimalRound);
            if (mode < MidpointRounding.ToEven || mode > MidpointRounding.AwayFromZero)
            {
                throw new ArgumentException(SR.Format(SR.Argument_InvalidEnumValue, mode, nameof(MidpointRounding)), nameof(mode));
            }
            Contract.EndContractBlock();

            if (mode == MidpointRounding.ToEven)
            {
                FCallRound(ref d, decimals);
            }
            else
            {
                InternalRoundFromZero(ref d, decimals);
            }
            return d;
        }

        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern void FCallRound(ref Decimal d, int decimals);

        // Subtracts two Decimal values.
        //
        public static Decimal Subtract(Decimal d1, Decimal d2)
        {
            FCallAddSub(ref d1, ref d2, DECIMAL_NEG);
            return d1;
        }

        // Converts a Decimal to an unsigned byte. The Decimal value is rounded
        // towards zero to the nearest integer value, and the result of this
        // operation is returned as a byte.
        //
        public static byte ToByte(Decimal value)
        {
            uint temp;
            try
            {
                temp = ToUInt32(value);
            }
            catch (OverflowException e)
            {
                throw new OverflowException(SR.Overflow_Byte, e);
            }
            if (temp < Byte.MinValue || temp > Byte.MaxValue) throw new OverflowException(SR.Overflow_Byte);
            return (byte)temp;
        }

        // Converts a Decimal to a signed byte. The Decimal value is rounded
        // towards zero to the nearest integer value, and the result of this
        // operation is returned as a byte.
        //
        [CLSCompliant(false)]
        public static sbyte ToSByte(Decimal value)
        {
            int temp;
            try
            {
                temp = ToInt32(value);
            }
            catch (OverflowException e)
            {
                throw new OverflowException(SR.Overflow_SByte, e);
            }
            if (temp < SByte.MinValue || temp > SByte.MaxValue) throw new OverflowException(SR.Overflow_SByte);
            return (sbyte)temp;
        }

        // Converts a Decimal to a short. The Decimal value is
        // rounded towards zero to the nearest integer value, and the result of
        // this operation is returned as a short.
        //
        public static short ToInt16(Decimal value)
        {
            int temp;
            try
            {
                temp = ToInt32(value);
            }
            catch (OverflowException e)
            {
                throw new OverflowException(SR.Overflow_Int16, e);
            }
            if (temp < Int16.MinValue || temp > Int16.MaxValue) throw new OverflowException(SR.Overflow_Int16);
            return (short)temp;
        }


        // Converts a Decimal to a Currency. Since a Currency
        // has fewer significant digits than a Decimal, this operation may
        // produce round-off errors.
        //
        internal static Currency ToCurrency(Decimal d)
        {
            Currency result = new Currency();
            FCallToCurrency(ref result, d);
            return result;
        }

        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern void FCallToCurrency(ref Currency result, Decimal d);

        // Converts a Decimal to a double. Since a double has fewer significant
        // digits than a Decimal, this operation may produce round-off errors.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        public static extern double ToDouble(Decimal d);

        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        internal static extern int FCallToInt32(Decimal d);

        // Converts a Decimal to an integer. The Decimal value is rounded towards
        // zero to the nearest integer value, and the result of this operation is
        // returned as an integer.
        //
        public static int ToInt32(Decimal d)
        {
            if ((d.flags & ScaleMask) != 0) FCallTruncate(ref d);
            if (d.hi == 0 && d.mid == 0)
            {
                int i = d.lo;
                if (d.flags >= 0)
                {
                    if (i >= 0) return i;
                }
                else
                {
                    i = -i;
                    if (i <= 0) return i;
                }
            }
            throw new OverflowException(SR.Overflow_Int32);
        }

        // Converts a Decimal to a long. The Decimal value is rounded towards zero
        // to the nearest integer value, and the result of this operation is
        // returned as a long.
        //
        public static long ToInt64(Decimal d)
        {
            if ((d.flags & ScaleMask) != 0) FCallTruncate(ref d);
            if (d.hi == 0)
            {
                long l = d.lo & 0xFFFFFFFFL | (long)d.mid << 32;
                if (d.flags >= 0)
                {
                    if (l >= 0) return l;
                }
                else
                {
                    l = -l;
                    if (l <= 0) return l;
                }
            }
            throw new OverflowException(SR.Overflow_Int64);
        }

        // Converts a Decimal to an ushort. The Decimal 
        // value is rounded towards zero to the nearest integer value, and the 
        // result of this operation is returned as an ushort.
        //
        [CLSCompliant(false)]
        public static ushort ToUInt16(Decimal value)
        {
            uint temp;
            try
            {
                temp = ToUInt32(value);
            }
            catch (OverflowException e)
            {
                throw new OverflowException(SR.Overflow_UInt16, e);
            }
            if (temp < UInt16.MinValue || temp > UInt16.MaxValue) throw new OverflowException(SR.Overflow_UInt16);
            return (ushort)temp;
        }

        // Converts a Decimal to an unsigned integer. The Decimal 
        // value is rounded towards zero to the nearest integer value, and the 
        // result of this operation is returned as an unsigned integer.
        //
        [CLSCompliant(false)]
        public static uint ToUInt32(Decimal d)
        {
            if ((d.flags & ScaleMask) != 0) FCallTruncate(ref d);
            if (d.hi == 0 && d.mid == 0)
            {
                uint i = (uint)d.lo;
                if (d.flags >= 0 || i == 0)
                    return i;
            }
            throw new OverflowException(SR.Overflow_UInt32);
        }

        // Converts a Decimal to an unsigned long. The Decimal 
        // value is rounded towards zero to the nearest integer value, and the 
        // result of this operation is returned as a long.
        //
        [CLSCompliant(false)]
        public static ulong ToUInt64(Decimal d)
        {
            if ((d.flags & ScaleMask) != 0) FCallTruncate(ref d);
            if (d.hi == 0)
            {
                ulong l = ((ulong)(uint)d.lo) | ((ulong)(uint)d.mid << 32);
                if (d.flags >= 0 || l == 0)
                    return l;
            }
            throw new OverflowException(SR.Overflow_UInt64);
        }

        // Converts a Decimal to a float. Since a float has fewer significant
        // digits than a Decimal, this operation may produce round-off errors.
        //
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        public static extern float ToSingle(Decimal d);

        // Truncates a Decimal to an integer value. The Decimal argument is rounded
        // towards zero to the nearest integer value, corresponding to removing all
        // digits after the decimal point.
        //
        public static Decimal Truncate(Decimal d)
        {
            FCallTruncate(ref d);
            return d;
        }


        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern void FCallTruncate(ref Decimal d);


        public static implicit operator Decimal(byte value)
        {
            return new Decimal(value);
        }

        [CLSCompliant(false)]
        public static implicit operator Decimal(sbyte value)
        {
            return new Decimal(value);
        }

        public static implicit operator Decimal(short value)
        {
            return new Decimal(value);
        }

        [CLSCompliant(false)]
        public static implicit operator Decimal(ushort value)
        {
            return new Decimal(value);
        }

        public static implicit operator Decimal(char value)
        {
            return new Decimal(value);
        }

        public static implicit operator Decimal(int value)
        {
            return new Decimal(value);
        }

        [CLSCompliant(false)]
        public static implicit operator Decimal(uint value)
        {
            return new Decimal(value);
        }

        public static implicit operator Decimal(long value)
        {
            return new Decimal(value);
        }

        [CLSCompliant(false)]
        public static implicit operator Decimal(ulong value)
        {
            return new Decimal(value);
        }


        public static explicit operator Decimal(float value)
        {
            return new Decimal(value);
        }

        public static explicit operator Decimal(double value)
        {
            return new Decimal(value);
        }

        public static explicit operator byte(Decimal value)
        {
            return ToByte(value);
        }

        [CLSCompliant(false)]
        public static explicit operator sbyte(Decimal value)
        {
            return ToSByte(value);
        }

        public static explicit operator char(Decimal value)
        {
            UInt16 temp;
            try
            {
                temp = ToUInt16(value);
            }
            catch (OverflowException e)
            {
                throw new OverflowException(SR.Overflow_Char, e);
            }
            return (char)temp;
        }

        public static explicit operator short(Decimal value)
        {
            return ToInt16(value);
        }

        [CLSCompliant(false)]
        public static explicit operator ushort(Decimal value)
        {
            return ToUInt16(value);
        }

        public static explicit operator int(Decimal value)
        {
            return ToInt32(value);
        }

        [CLSCompliant(false)]
        public static explicit operator uint(Decimal value)
        {
            return ToUInt32(value);
        }

        public static explicit operator long(Decimal value)
        {
            return ToInt64(value);
        }

        [CLSCompliant(false)]
        public static explicit operator ulong(Decimal value)
        {
            return ToUInt64(value);
        }

        public static explicit operator float(Decimal value)
        {
            return ToSingle(value);
        }

        public static explicit operator double(Decimal value)
        {
            return ToDouble(value);
        }

        public static Decimal operator +(Decimal d)
        {
            return d;
        }

        public static Decimal operator -(Decimal d)
        {
            return Negate(d);
        }

        public static Decimal operator ++(Decimal d)
        {
            return Add(d, One);
        }

        public static Decimal operator --(Decimal d)
        {
            return Subtract(d, One);
        }

        public static Decimal operator +(Decimal d1, Decimal d2)
        {
            FCallAddSub(ref d1, ref d2, DECIMAL_ADD);
            return d1;
        }

        public static Decimal operator -(Decimal d1, Decimal d2)
        {
            FCallAddSub(ref d1, ref d2, DECIMAL_NEG);
            return d1;
        }

        public static Decimal operator *(Decimal d1, Decimal d2)
        {
            FCallMultiply(ref d1, ref d2);
            return d1;
        }

        public static Decimal operator /(Decimal d1, Decimal d2)
        {
            FCallDivide(ref d1, ref d2);
            return d1;
        }

        public static Decimal operator %(Decimal d1, Decimal d2)
        {
            return Remainder(d1, d2);
        }

        public static bool operator ==(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) == 0;
        }

        public static bool operator !=(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) != 0;
        }

        public static bool operator <(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) < 0;
        }

        public static bool operator <=(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) <= 0;
        }

        public static bool operator >(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) > 0;
        }

        public static bool operator >=(Decimal d1, Decimal d2)
        {
            return FCallCompare(ref d1, ref d2) >= 0;
        }

        //
        // IConvertible implementation
        //

        public TypeCode GetTypeCode()
        {
            return TypeCode.Decimal;
        }

        bool IConvertible.ToBoolean(IFormatProvider provider)
        {
            return Convert.ToBoolean(this);
        }


        char IConvertible.ToChar(IFormatProvider provider)
        {
            throw new InvalidCastException(SR.Format(SR.InvalidCast_FromTo, "Decimal", "Char"));
        }

        sbyte IConvertible.ToSByte(IFormatProvider provider)
        {
            return Convert.ToSByte(this);
        }

        byte IConvertible.ToByte(IFormatProvider provider)
        {
            return Convert.ToByte(this);
        }

        short IConvertible.ToInt16(IFormatProvider provider)
        {
            return Convert.ToInt16(this);
        }

        ushort IConvertible.ToUInt16(IFormatProvider provider)
        {
            return Convert.ToUInt16(this);
        }

        int IConvertible.ToInt32(IFormatProvider provider)
        {
            return Convert.ToInt32(this);
        }

        uint IConvertible.ToUInt32(IFormatProvider provider)
        {
            return Convert.ToUInt32(this);
        }

        long IConvertible.ToInt64(IFormatProvider provider)
        {
            return Convert.ToInt64(this);
        }

        ulong IConvertible.ToUInt64(IFormatProvider provider)
        {
            return Convert.ToUInt64(this);
        }

        float IConvertible.ToSingle(IFormatProvider provider)
        {
            return Convert.ToSingle(this);
        }

        double IConvertible.ToDouble(IFormatProvider provider)
        {
            return Convert.ToDouble(this);
        }

        Decimal IConvertible.ToDecimal(IFormatProvider provider)
        {
            return this;
        }

        DateTime IConvertible.ToDateTime(IFormatProvider provider)
        {
            throw new InvalidCastException(SR.Format(SR.InvalidCast_FromTo, "Decimal", "DateTime"));
        }

        Object IConvertible.ToType(Type type, IFormatProvider provider)
        {
            return Convert.DefaultToType((IConvertible)this, type, provider);
        }
    }
}