forked from denisenkom/go-mssqldb
-
Notifications
You must be signed in to change notification settings - Fork 80
/
Copy pathtypes.go
1699 lines (1623 loc) · 41.7 KB
/
types.go
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
package mssql
import (
"bytes"
"encoding/binary"
"fmt"
"io"
"math"
"reflect"
"strconv"
"strings"
"time"
"github.com/microsoft/go-mssqldb/internal/cp"
"github.com/microsoft/go-mssqldb/internal/decimal"
"github.com/microsoft/go-mssqldb/msdsn"
)
// fixed-length data types
// http://msdn.microsoft.com/en-us/library/dd341171.aspx
const (
typeNull = 0x1f
typeInt1 = 0x30
typeBit = 0x32
typeInt2 = 0x34
typeInt4 = 0x38
typeDateTim4 = 0x3a
typeFlt4 = 0x3b
typeMoney = 0x3c
typeDateTime = 0x3d
typeFlt8 = 0x3e
typeMoney4 = 0x7a
typeInt8 = 0x7f
)
// variable-length data types
// http://msdn.microsoft.com/en-us/library/dd358341.aspx
const (
// byte len types
typeGuid = 0x24
typeIntN = 0x26
typeDecimal = 0x37 // legacy
typeNumeric = 0x3f // legacy
typeBitN = 0x68
typeDecimalN = 0x6a
typeNumericN = 0x6c
typeFltN = 0x6d
typeMoneyN = 0x6e
typeDateTimeN = 0x6f
typeDateN = 0x28
typeTimeN = 0x29
typeDateTime2N = 0x2a
typeDateTimeOffsetN = 0x2b
typeChar = 0x2f // legacy
typeVarChar = 0x27 // legacy
typeBinary = 0x2d // legacy
typeVarBinary = 0x25 // legacy
// short length types
typeBigVarBin = 0xa5
typeBigVarChar = 0xa7
typeBigBinary = 0xad
typeBigChar = 0xaf
typeNVarChar = 0xe7
typeNChar = 0xef
typeXml = 0xf1
typeUdt = 0xf0
typeTvp = 0xf3
// long length types
typeText = 0x23
typeImage = 0x22
typeNText = 0x63
typeVariant = 0x62
)
const _PLP_NULL = 0xFFFFFFFFFFFFFFFF
const _UNKNOWN_PLP_LEN = 0xFFFFFFFFFFFFFFFE
const _PLP_TERMINATOR = 0x00000000
// TVP COLUMN FLAGS
const _TVP_END_TOKEN = 0x00
const _TVP_ROW_TOKEN = 0x01
// TVP_COLMETADATA definition
// https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-tds/0dfc5367-a388-4c92-9ba4-4d28e775acbc
const (
fDefault = 0x200
)
// TYPE_INFO rule
// http://msdn.microsoft.com/en-us/library/dd358284.aspx
type typeInfo struct {
TypeId uint8
UserType uint32
Flags uint16
Size int
Scale uint8
Prec uint8
Buffer []byte
Collation cp.Collation
UdtInfo udtInfo
XmlInfo xmlInfo
Reader func(ti *typeInfo, r *tdsBuffer, cryptoMeta *cryptoMetadata) (res interface{})
Writer func(w io.Writer, ti typeInfo, buf []byte) (err error)
}
// Common Language Runtime (CLR) Instances
// http://msdn.microsoft.com/en-us/library/dd357962.aspx
type udtInfo struct {
//MaxByteSize uint32
DBName string
SchemaName string
TypeName string
AssemblyQualifiedName string
}
// XML Values
// http://msdn.microsoft.com/en-us/library/dd304764.aspx
type xmlInfo struct {
SchemaPresent uint8
DBName string
OwningSchema string
XmlSchemaCollection string
}
func readTypeInfo(r *tdsBuffer, typeId byte, c *cryptoMetadata, encoding msdsn.EncodeParameters) (res typeInfo) {
res.TypeId = typeId
switch typeId {
case typeNull, typeInt1, typeBit, typeInt2, typeInt4, typeDateTim4,
typeFlt4, typeMoney, typeDateTime, typeFlt8, typeMoney4, typeInt8:
// those are fixed length types
switch res.TypeId {
case typeNull:
res.Size = 0
case typeInt1, typeBit:
res.Size = 1
case typeInt2:
res.Size = 2
case typeInt4, typeDateTim4, typeFlt4, typeMoney4:
res.Size = 4
case typeMoney, typeDateTime, typeFlt8, typeInt8:
res.Size = 8
}
res.Reader = readFixedType
res.Buffer = make([]byte, res.Size)
default: // all others are VARLENTYPE
readVarLen(&res, r, c, encoding)
}
return
}
// https://msdn.microsoft.com/en-us/library/dd358284.aspx
func writeTypeInfo(w io.Writer, ti *typeInfo, out bool, encoding msdsn.EncodeParameters) (err error) {
err = binary.Write(w, binary.LittleEndian, ti.TypeId)
if err != nil {
return
}
switch ti.TypeId {
case typeNull, typeInt1, typeBit, typeInt2, typeInt4, typeDateTim4,
typeFlt4, typeMoney, typeDateTime, typeFlt8, typeMoney4, typeInt8:
// those are fixed length
// https://msdn.microsoft.com/en-us/library/dd341171.aspx
ti.Writer = writeFixedType
case typeTvp:
ti.Writer = writeFixedType
default: // all others are VARLENTYPE
err = writeVarLen(w, ti, out, encoding)
if err != nil {
return
}
}
return
}
func writeFixedType(w io.Writer, ti typeInfo, buf []byte) (err error) {
_, err = w.Write(buf)
return
}
// https://msdn.microsoft.com/en-us/library/dd358341.aspx
func writeVarLen(w io.Writer, ti *typeInfo, out bool, encoding msdsn.EncodeParameters) (err error) {
switch ti.TypeId {
case typeDateN:
ti.Writer = writeByteLenType
case typeTimeN, typeDateTime2N, typeDateTimeOffsetN:
if err = binary.Write(w, binary.LittleEndian, ti.Scale); err != nil {
return
}
ti.Writer = writeByteLenType
case typeIntN, typeDecimal, typeNumeric,
typeBitN, typeDecimalN, typeNumericN, typeFltN,
typeMoneyN, typeDateTimeN, typeChar,
typeVarChar, typeBinary, typeVarBinary:
// byle len types
if ti.Size > 0xff {
panic("Invalid size for BYTELEN_TYPE")
}
if err = binary.Write(w, binary.LittleEndian, uint8(ti.Size)); err != nil {
return
}
switch ti.TypeId {
case typeDecimal, typeNumeric, typeDecimalN, typeNumericN:
err = binary.Write(w, binary.LittleEndian, ti.Prec)
if err != nil {
return
}
err = binary.Write(w, binary.LittleEndian, ti.Scale)
if err != nil {
return
}
}
ti.Writer = writeByteLenType
case typeGuid:
if !(ti.Size == 0x10 || ti.Size == 0x00) {
panic("Invalid size for UNIQUEIDENTIFIER")
}
if err = binary.Write(w, binary.LittleEndian, uint8(ti.Size)); err != nil {
return
}
if encoding.GuidConversion {
ti.Writer = writeGuidTypeWithConversion
} else {
ti.Writer = writeGuidTypeWithoutConversion
}
case typeBigVarBin, typeBigVarChar, typeBigBinary, typeBigChar,
typeNVarChar, typeNChar, typeXml, typeUdt:
// short len types
if ti.Size > 8000 || ti.Size == 0 || out {
if err = binary.Write(w, binary.LittleEndian, uint16(0xffff)); err != nil {
return
}
ti.Writer = writePLPType
} else {
if err = binary.Write(w, binary.LittleEndian, uint16(ti.Size)); err != nil {
return
}
ti.Writer = writeShortLenType
}
switch ti.TypeId {
case typeBigVarChar, typeBigChar, typeNVarChar, typeNChar:
if err = writeCollation(w, ti.Collation); err != nil {
return
}
case typeXml:
if err = binary.Write(w, binary.LittleEndian, ti.XmlInfo.SchemaPresent); err != nil {
return
}
}
case typeText, typeImage, typeNText, typeVariant:
// LONGLEN_TYPE
if err = binary.Write(w, binary.LittleEndian, uint32(ti.Size)); err != nil {
return
}
if err = writeCollation(w, ti.Collation); err != nil {
return
}
ti.Writer = writeLongLenType
default:
panic("Invalid type")
}
return
}
// http://msdn.microsoft.com/en-us/library/ee780895.aspx
func decodeDateTim4(buf []byte) time.Time {
days := binary.LittleEndian.Uint16(buf)
mins := binary.LittleEndian.Uint16(buf[2:])
return time.Date(1900, 1, 1+int(days),
0, int(mins), 0, 0, time.UTC)
}
func encodeDateTim4(val time.Time) (buf []byte) {
buf = make([]byte, 4)
ref := time.Date(1900, 1, 1, 0, 0, 0, 0, time.UTC)
dur := val.Sub(ref)
days := dur / (24 * time.Hour)
mins := val.Hour()*60 + val.Minute()
if days < 0 {
days = 0
mins = 0
}
binary.LittleEndian.PutUint16(buf[:2], uint16(days))
binary.LittleEndian.PutUint16(buf[2:], uint16(mins))
return
}
// encodes datetime value
// type identifier is typeDateTimeN
func encodeDateTime(t time.Time) (res []byte) {
// base date in days since Jan 1st 1900
basedays := gregorianDays(1900, 1)
// days since Jan 1st 1900 (same TZ as t)
days := gregorianDays(t.Year(), t.YearDay()) - basedays
tm := 300*(t.Second()+t.Minute()*60+t.Hour()*60*60) + nanosToThreeHundredthsOfASecond(t.Nanosecond())
// minimum and maximum possible
mindays := gregorianDays(1753, 1) - basedays
maxdays := gregorianDays(9999, 365) - basedays
if days < mindays {
days = mindays
tm = 0
}
if days > maxdays {
days = maxdays
tm = (23*60*60+59*60+59)*300 + 299
}
res = make([]byte, 8)
binary.LittleEndian.PutUint32(res[0:4], uint32(days))
binary.LittleEndian.PutUint32(res[4:8], uint32(tm))
return
}
func decodeDateTime(buf []byte) time.Time {
days := int32(binary.LittleEndian.Uint32(buf))
tm := binary.LittleEndian.Uint32(buf[4:])
ns := threeHundredthsOfASecondToNanos(int(tm % 300))
secs := int(tm / 300)
return time.Date(1900, 1, 1+int(days),
0, 0, secs, ns, time.UTC)
}
func threeHundredthsOfASecondToNanos(ths int) int {
return int(math.Trunc(float64(ths)/0.3+0.5)) * 1000000
}
func nanosToThreeHundredthsOfASecond(ns int) int {
return int(math.Round(float64(ns) * 3 / 1e7))
}
func readFixedType(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
r.ReadFull(ti.Buffer)
buf := ti.Buffer
switch ti.TypeId {
case typeNull:
return nil
case typeInt1:
return int64(buf[0])
case typeBit:
return buf[0] != 0
case typeInt2:
return int64(int16(binary.LittleEndian.Uint16(buf)))
case typeInt4:
return int64(int32(binary.LittleEndian.Uint32(buf)))
case typeDateTim4:
return decodeDateTim4(buf)
case typeFlt4:
return math.Float32frombits(binary.LittleEndian.Uint32(buf))
case typeMoney4:
return decodeMoney4(buf)
case typeMoney:
return decodeMoney(buf)
case typeDateTime:
return decodeDateTime(buf)
case typeFlt8:
return math.Float64frombits(binary.LittleEndian.Uint64(buf))
case typeInt8:
return int64(binary.LittleEndian.Uint64(buf))
default:
badStreamPanicf("Invalid typeid")
}
panic("shoulnd't get here")
}
func readByteLenTypeWithEncoding(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata, encoding msdsn.EncodeParameters) interface{} {
var size byte
if c != nil {
size = byte(r.rsize)
} else {
size = r.byte()
}
if size == 0 {
return nil
}
r.ReadFull(ti.Buffer[:size])
buf := ti.Buffer[:size]
switch ti.TypeId {
case typeDateN:
if len(buf) != 3 {
badStreamPanicf("Invalid size for DATENTYPE")
}
return decodeDate(buf)
case typeTimeN:
return decodeTime(ti.Scale, buf)
case typeDateTime2N:
return decodeDateTime2(ti.Scale, buf)
case typeDateTimeOffsetN:
return decodeDateTimeOffset(ti.Scale, buf)
case typeGuid:
return decodeGuid(buf, encoding)
case typeIntN:
switch len(buf) {
case 1:
return int64(buf[0])
case 2:
return int64(int16((binary.LittleEndian.Uint16(buf))))
case 4:
return int64(int32(binary.LittleEndian.Uint32(buf)))
case 8:
return int64(binary.LittleEndian.Uint64(buf))
default:
badStreamPanicf("Invalid size for INTNTYPE: %d", len(buf))
}
case typeDecimal, typeNumeric, typeDecimalN, typeNumericN:
return decodeDecimal(ti.Prec, ti.Scale, buf)
case typeBitN:
if len(buf) != 1 {
badStreamPanicf("Invalid size for BITNTYPE")
}
return buf[0] != 0
case typeFltN:
switch len(buf) {
case 4:
return float64(math.Float32frombits(binary.LittleEndian.Uint32(buf)))
case 8:
return math.Float64frombits(binary.LittleEndian.Uint64(buf))
default:
badStreamPanicf("Invalid size for FLTNTYPE")
}
case typeMoneyN:
switch len(buf) {
case 4:
return decodeMoney4(buf)
case 8:
return decodeMoney(buf)
default:
badStreamPanicf("Invalid size for MONEYNTYPE")
}
case typeDateTim4:
return decodeDateTim4(buf)
case typeDateTime:
return decodeDateTime(buf)
case typeDateTimeN:
switch len(buf) {
case 4:
return decodeDateTim4(buf)
case 8:
return decodeDateTime(buf)
default:
badStreamPanicf("Invalid size for DATETIMENTYPE")
}
case typeChar, typeVarChar:
return decodeChar(ti.Collation, buf)
case typeBinary, typeVarBinary:
// a copy, because the backing array for ti.Buffer is reused
// and can be overwritten by the next row while this row waits
// in a buffered chan
cpy := make([]byte, len(buf))
copy(cpy, buf)
return cpy
default:
badStreamPanicf("Invalid typeid")
}
panic("shouldn't get here")
}
func readByteLenTypeWithGuidConversion(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
return readByteLenTypeWithEncoding(ti, r, c, msdsn.EncodeParameters{GuidConversion: true})
}
func readByteLenType(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
return readByteLenTypeWithEncoding(ti, r, c, msdsn.EncodeParameters{GuidConversion: false})
}
func writeByteLenType(w io.Writer, ti typeInfo, buf []byte) (err error) {
if ti.Size > 0xff {
panic("Invalid size for BYTELEN_TYPE")
}
err = binary.Write(w, binary.LittleEndian, uint8(len(buf)))
if err != nil {
return
}
_, err = w.Write(buf)
return
}
func writeGuidType(w io.Writer, ti typeInfo, buf []byte, encoding msdsn.EncodeParameters) (err error) {
if !(ti.Size == 0x10 || ti.Size == 0x00) {
panic("Invalid size for UNIQUEIDENTIFIER")
}
err = binary.Write(w, binary.LittleEndian, uint8(len(buf)))
if err != nil {
return
}
if ti.Size == 0x10 {
res := make([]byte, 0x10)
copy(res, buf)
if encoding.GuidConversion {
binary.BigEndian.PutUint32(res[0:4], binary.LittleEndian.Uint32(res[0:4]))
binary.BigEndian.PutUint16(res[4:6], binary.LittleEndian.Uint16(res[4:6]))
binary.BigEndian.PutUint16(res[6:8], binary.LittleEndian.Uint16(res[6:8]))
}
_, err = w.Write(res)
}
return
}
func writeGuidTypeWithConversion(w io.Writer, ti typeInfo, buf []byte) (err error) {
return writeGuidType(w, ti, buf, msdsn.EncodeParameters{GuidConversion: true})
}
func writeGuidTypeWithoutConversion(w io.Writer, ti typeInfo, buf []byte) (err error) {
return writeGuidType(w, ti, buf, msdsn.EncodeParameters{GuidConversion: false})
}
func readShortLenType(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
var size uint16
if c != nil {
size = uint16(r.rsize)
} else {
size = r.uint16()
}
if size == 0xffff {
return nil
}
r.ReadFull(ti.Buffer[:size])
buf := ti.Buffer[:size]
switch ti.TypeId {
case typeBigVarChar, typeBigChar:
return decodeChar(ti.Collation, buf)
case typeBigVarBin, typeBigBinary:
// a copy, because the backing array for ti.Buffer is reused
// and can be overwritten by the next row while this row waits
// in a buffered chan
cpy := make([]byte, len(buf))
copy(cpy, buf)
return cpy
case typeNVarChar, typeNChar:
return decodeNChar(buf)
case typeUdt:
return decodeUdt(*ti, buf)
default:
badStreamPanicf("Invalid typeid")
}
panic("shoulnd't get here")
}
func writeShortLenType(w io.Writer, ti typeInfo, buf []byte) (err error) {
if buf == nil {
err = binary.Write(w, binary.LittleEndian, uint16(0xffff))
return
}
if ti.Size > 0xfffe {
panic("Invalid size for USHORTLEN_TYPE")
}
err = binary.Write(w, binary.LittleEndian, uint16(ti.Size))
if err != nil {
return
}
_, err = w.Write(buf)
return
}
func readLongLenType(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
// information about this format can be found here:
// http://msdn.microsoft.com/en-us/library/dd304783.aspx
// and here:
// http://msdn.microsoft.com/en-us/library/dd357254.aspx
textptrsize := int(r.byte())
if textptrsize == 0 {
return nil
}
textptr := make([]byte, textptrsize)
r.ReadFull(textptr)
timestamp := r.uint64()
_ = timestamp // ignore timestamp
size := r.int32()
if size == -1 {
return nil
}
buf := make([]byte, size)
r.ReadFull(buf)
switch ti.TypeId {
case typeText:
return decodeChar(ti.Collation, buf)
case typeImage:
return buf
case typeNText:
return decodeNChar(buf)
default:
badStreamPanicf("Invalid typeid")
}
panic("shoulnd't get here")
}
func writeLongLenType(w io.Writer, ti typeInfo, buf []byte) (err error) {
//textptr
err = binary.Write(w, binary.LittleEndian, byte(0x10))
if err != nil {
return
}
err = binary.Write(w, binary.LittleEndian, uint64(0xFFFFFFFFFFFFFFFF))
if err != nil {
return
}
err = binary.Write(w, binary.LittleEndian, uint64(0xFFFFFFFFFFFFFFFF))
if err != nil {
return
}
//timestamp?
err = binary.Write(w, binary.LittleEndian, uint64(0xFFFFFFFFFFFFFFFF))
if err != nil {
return
}
err = binary.Write(w, binary.LittleEndian, uint32(ti.Size))
if err != nil {
return
}
_, err = w.Write(buf)
return
}
func readCollation(r *tdsBuffer) (res cp.Collation) {
res.LcidAndFlags = r.uint32()
res.SortId = r.byte()
return
}
func writeCollation(w io.Writer, col cp.Collation) (err error) {
if err = binary.Write(w, binary.LittleEndian, col.LcidAndFlags); err != nil {
return
}
err = binary.Write(w, binary.LittleEndian, col.SortId)
return
}
// reads variant value
// http://msdn.microsoft.com/en-us/library/dd303302.aspx
func readVariantTypeWithEncoding(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata, encoding msdsn.EncodeParameters) interface{} {
size := r.int32()
if size == 0 {
return nil
}
vartype := r.byte()
propbytes := int32(r.byte())
switch vartype {
case typeGuid:
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeGuid(buf, encoding)
case typeBit:
return r.byte() != 0
case typeInt1:
return int64(r.byte())
case typeInt2:
return int64(int16(r.uint16()))
case typeInt4:
return int64(r.int32())
case typeInt8:
return int64(r.uint64())
case typeDateTime:
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeDateTime(buf)
case typeDateTim4:
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeDateTim4(buf)
case typeFlt4:
return float64(math.Float32frombits(r.uint32()))
case typeFlt8:
return math.Float64frombits(r.uint64())
case typeMoney4:
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeMoney4(buf)
case typeMoney:
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeMoney(buf)
case typeDateN:
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeDate(buf)
case typeTimeN:
scale := r.byte()
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeTime(scale, buf)
case typeDateTime2N:
scale := r.byte()
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeDateTime2(scale, buf)
case typeDateTimeOffsetN:
scale := r.byte()
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeDateTimeOffset(scale, buf)
case typeBigVarBin, typeBigBinary:
r.uint16() // max length, ignoring
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return buf
case typeDecimalN, typeNumericN:
prec := r.byte()
scale := r.byte()
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeDecimal(prec, scale, buf)
case typeBigVarChar, typeBigChar:
col := readCollation(r)
r.uint16() // max length, ignoring
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeChar(col, buf)
case typeNVarChar, typeNChar:
_ = readCollation(r)
r.uint16() // max length, ignoring
buf := make([]byte, size-2-propbytes)
r.ReadFull(buf)
return decodeNChar(buf)
default:
badStreamPanicf("Invalid variant typeid")
}
panic("shoulnd't get here")
}
func readVariantTypeWithGuidConversion(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
return readVariantTypeWithEncoding(ti, r, c, msdsn.EncodeParameters{GuidConversion: true})
}
func readVariantType(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
return readVariantTypeWithEncoding(ti, r, c, msdsn.EncodeParameters{GuidConversion: false})
}
// partially length prefixed stream
// http://msdn.microsoft.com/en-us/library/dd340469.aspx
func readPLPType(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata) interface{} {
var bytesToDecode []byte
if c == nil {
size := r.uint64()
var buf *bytes.Buffer
switch size {
case _PLP_NULL:
// null
return nil
case _UNKNOWN_PLP_LEN:
// size unknown
buf = bytes.NewBuffer(make([]byte, 0, 1000))
default:
buf = bytes.NewBuffer(make([]byte, 0, size))
}
for {
chunksize := r.uint32()
if chunksize == 0 {
break
}
if _, err := io.CopyN(buf, r, int64(chunksize)); err != nil {
badStreamPanicf("Reading PLP type failed: %s", err.Error())
}
}
bytesToDecode = buf.Bytes()
} else {
bytesToDecode = r.rbuf
}
switch ti.TypeId {
case typeXml:
return decodeXml(*ti, bytesToDecode)
case typeBigVarChar, typeBigChar, typeText:
return decodeChar(ti.Collation, bytesToDecode)
case typeBigVarBin, typeBigBinary, typeImage:
return bytesToDecode
case typeNVarChar, typeNChar, typeNText:
return decodeNChar(bytesToDecode)
case typeUdt:
return decodeUdt(*ti, bytesToDecode)
}
panic("shouldn't get here")
}
func writePLPType(w io.Writer, ti typeInfo, buf []byte) (err error) {
if buf == nil {
err = binary.Write(w, binary.LittleEndian, uint64(_PLP_NULL))
return
}
if err = binary.Write(w, binary.LittleEndian, uint64(_UNKNOWN_PLP_LEN)); err != nil {
return
}
for {
chunksize := uint32(len(buf))
if chunksize == 0 {
err = binary.Write(w, binary.LittleEndian, uint32(_PLP_TERMINATOR))
return
}
if err = binary.Write(w, binary.LittleEndian, chunksize); err != nil {
return
}
if _, err = w.Write(buf[:chunksize]); err != nil {
return
}
buf = buf[chunksize:]
}
}
func readVarLen(ti *typeInfo, r *tdsBuffer, c *cryptoMetadata, encoding msdsn.EncodeParameters) {
switch ti.TypeId {
case typeDateN:
ti.Size = 3
ti.Reader = readByteLenType
ti.Buffer = make([]byte, ti.Size)
case typeTimeN, typeDateTime2N, typeDateTimeOffsetN:
ti.Scale = r.byte()
switch ti.Scale {
case 0, 1, 2:
ti.Size = 3
case 3, 4:
ti.Size = 4
case 5, 6, 7:
ti.Size = 5
default:
badStreamPanicf("Invalid scale for TIME/DATETIME2/DATETIMEOFFSET type")
}
switch ti.TypeId {
case typeDateTime2N:
ti.Size += 3
case typeDateTimeOffsetN:
ti.Size += 5
}
ti.Reader = readByteLenType
ti.Buffer = make([]byte, ti.Size)
case typeGuid, typeIntN, typeDecimal, typeNumeric,
typeBitN, typeDecimalN, typeNumericN, typeFltN,
typeMoneyN, typeDateTimeN, typeChar,
typeVarChar, typeBinary, typeVarBinary:
// byle len types
ti.Size = int(r.byte())
ti.Buffer = make([]byte, ti.Size)
switch ti.TypeId {
case typeDecimal, typeNumeric, typeDecimalN, typeNumericN:
ti.Prec = r.byte()
ti.Scale = r.byte()
}
if encoding.GuidConversion {
ti.Reader = readByteLenTypeWithGuidConversion
} else {
ti.Reader = readByteLenType
}
case typeXml:
ti.XmlInfo.SchemaPresent = r.byte()
if ti.XmlInfo.SchemaPresent != 0 {
// dbname
ti.XmlInfo.DBName = r.BVarChar()
// owning schema
ti.XmlInfo.OwningSchema = r.BVarChar()
// xml schema collection
ti.XmlInfo.XmlSchemaCollection = r.UsVarChar()
}
ti.Reader = readPLPType
case typeUdt:
ti.Size = int(r.uint16())
ti.UdtInfo.DBName = r.BVarChar()
ti.UdtInfo.SchemaName = r.BVarChar()
ti.UdtInfo.TypeName = r.BVarChar()
ti.UdtInfo.AssemblyQualifiedName = r.UsVarChar()
ti.Buffer = make([]byte, ti.Size)
ti.Reader = readPLPType
case typeBigVarBin, typeBigVarChar, typeBigBinary, typeBigChar,
typeNVarChar, typeNChar:
// short len types
ti.Size = int(r.uint16())
switch ti.TypeId {
case typeBigVarChar, typeBigChar, typeNVarChar, typeNChar:
ti.Collation = readCollation(r)
}
if ti.Size == 0xffff {
ti.Reader = readPLPType
} else {
ti.Buffer = make([]byte, ti.Size)
ti.Reader = readShortLenType
}
case typeText, typeImage, typeNText, typeVariant:
// LONGLEN_TYPE
ti.Size = int(r.int32())
switch ti.TypeId {
case typeText, typeNText:
ti.Collation = readCollation(r)
// ignore tablenames
numparts := int(r.byte())
for i := 0; i < numparts; i++ {
r.UsVarChar()
}
ti.Reader = readLongLenType
case typeImage:
// ignore tablenames
numparts := int(r.byte())
for i := 0; i < numparts; i++ {
r.UsVarChar()
}
ti.Reader = readLongLenType
case typeVariant:
if encoding.GuidConversion {
ti.Reader = readVariantTypeWithGuidConversion
} else {
ti.Reader = readVariantType
}
}
default:
badStreamPanicf("Invalid type %d", ti.TypeId)
}
}
func decodeMoney(buf []byte) []byte {
money := int64(uint64(buf[4]) |
uint64(buf[5])<<8 |
uint64(buf[6])<<16 |
uint64(buf[7])<<24 |
uint64(buf[0])<<32 |
uint64(buf[1])<<40 |
uint64(buf[2])<<48 |
uint64(buf[3])<<56)
return decimal.ScaleBytes(strconv.FormatInt(money, 10), 4)
}
func decodeMoney4(buf []byte) []byte {
money := int32(binary.LittleEndian.Uint32(buf[0:4]))
return decimal.ScaleBytes(strconv.FormatInt(int64(money), 10), 4)
}
func decodeGuid(buf []byte, encoding msdsn.EncodeParameters) []byte {
res := make([]byte, 16)
copy(res, buf)
if encoding.GuidConversion {
binary.LittleEndian.PutUint32(res[0:4], binary.BigEndian.Uint32(res[0:4]))
binary.LittleEndian.PutUint16(res[4:6], binary.BigEndian.Uint16(res[4:6]))
binary.LittleEndian.PutUint16(res[6:8], binary.BigEndian.Uint16(res[6:8]))
}
return res
}
func decodeDecimal(prec uint8, scale uint8, buf []byte) []byte {
sign := buf[0]
var dec decimal.Decimal
dec.SetPositive(sign != 0)
dec.SetPrec(prec)
dec.SetScale(scale)
buf = buf[1:]
l := len(buf) / 4
for i := 0; i < l; i++ {
dec.SetInteger(binary.LittleEndian.Uint32(buf[0:4]), uint8(i))
buf = buf[4:]
}
return dec.Bytes()
}
// http://msdn.microsoft.com/en-us/library/ee780895.aspx
func decodeDateInt(buf []byte) (days int) {
days = int(buf[0]) + int(buf[1])*256 + int(buf[2])*256*256
return
}
func decodeDate(buf []byte) time.Time {
return time.Date(1, 1, 1+decodeDateInt(buf), 0, 0, 0, 0, time.UTC)
}
func encodeDate(val time.Time) (buf []byte) {
days, _, _ := dateTime2(val)
buf = make([]byte, 3)
buf[0] = byte(days)
buf[1] = byte(days >> 8)
buf[2] = byte(days >> 16)
return
}
func decodeTimeInt(scale uint8, buf []byte) (sec int, ns int) {
var acc uint64 = 0
for i := len(buf) - 1; i >= 0; i-- {
acc <<= 8
acc |= uint64(buf[i])
}
for i := 0; i < 7-int(scale); i++ {
acc *= 10
}
nsbig := acc * 100
sec = int(nsbig / 1000000000)
ns = int(nsbig % 1000000000)
return
}
// calculate size of time field in bytes
func calcTimeSize(scale int) int {
if scale <= 2 {
return 3
} else if scale <= 4 {
return 4
} else {
return 5
}
}
// writes time value into a field buffer
// buffer should be at least calcTimeSize long
func encodeTimeInt(seconds, ns, scale int, buf []byte) {
ns_total := int64(seconds)*1000*1000*1000 + int64(ns)
t := ns_total / int64(math.Pow10(int(scale)*-1)*1e9)
buf[0] = byte(t)