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
|
//------------------------------------------------------------------------------
// <copyright file="Select.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
// <owner current="false" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------
namespace System.Data {
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data.Common;
using System.Diagnostics;
internal sealed class Select {
private readonly DataTable table;
private readonly IndexField[] IndexFields;
private DataViewRowState recordStates;
private DataExpression rowFilter;
private ExpressionNode expression;
private Index index;
private int[] records;
private int recordCount;
private ExpressionNode linearExpression;
private bool candidatesForBinarySearch;
private sealed class ColumnInfo {
public bool flag = false; // Misc. Use
public bool equalsOperator = false; // True when the associated expr has = Operator defined
public BinaryNode expr = null; // Binary Search capable expression associated
}
ColumnInfo[] candidateColumns;
int nCandidates;
int matchedCandidates;
public Select(DataTable table, string filterExpression, string sort, DataViewRowState recordStates) {
this.table = table;
IndexFields = table.ParseSortString(sort);
if (filterExpression != null && filterExpression.Length > 0) {
this.rowFilter = new DataExpression(this.table, filterExpression);
this.expression = this.rowFilter.ExpressionNode;
}
this.recordStates = recordStates;
}
private bool IsSupportedOperator(int op) {
return ((op >= Operators.EqualTo && op <= Operators.LessOrEqual) || op == Operators.Is || op == Operators.IsNot);
}
// Microsoft : Gathers all linear expressions in to this.linearExpression and all binary expressions in to their respective candidate columns expressions
private void AnalyzeExpression(BinaryNode expr) {
if (this.linearExpression == this.expression)
return;
if (expr.op == Operators.Or) {
this.linearExpression = this.expression;
return;
}
else
if (expr.op == Operators.And) {
bool isLeft=false, isRight=false;
if (expr.left is BinaryNode) {
AnalyzeExpression((BinaryNode)expr.left);
if (this.linearExpression == this.expression)
return;
isLeft = true;
}
else {
UnaryNode unaryNode = expr.left as UnaryNode;
if (unaryNode != null) {
while (unaryNode.op == Operators.Noop && unaryNode.right is UnaryNode && ((UnaryNode)unaryNode.right).op == Operators.Noop) {
unaryNode = (UnaryNode)unaryNode.right;
}
if (unaryNode.op == Operators.Noop && unaryNode.right is BinaryNode) {
AnalyzeExpression((BinaryNode)(unaryNode.right));
if (this.linearExpression == this.expression) {
return;
}
isLeft = true;
}
}
}
if (expr.right is BinaryNode) {
AnalyzeExpression((BinaryNode)expr.right);
if (this.linearExpression == this.expression)
return;
isRight = true;
}
else {
UnaryNode unaryNode = expr.right as UnaryNode;
if (unaryNode != null) {
while (unaryNode.op == Operators.Noop && unaryNode.right is UnaryNode && ((UnaryNode)unaryNode.right).op == Operators.Noop) {
unaryNode = (UnaryNode)unaryNode.right;
}
if (unaryNode.op == Operators.Noop && unaryNode.right is BinaryNode) {
AnalyzeExpression((BinaryNode)(unaryNode.right));
if (this.linearExpression == this.expression) {
return;
}
// SQLBU 497534: DataTable.Select() returns incorrect results with multiple statements depending '(' and ')'
// from copy paste error fixing SQLBU 342141
isRight = true;
}
}
}
if (isLeft && isRight)
return;
ExpressionNode e = isLeft ? expr.right : expr.left;
this.linearExpression = (this.linearExpression == null ? e : new BinaryNode(table, Operators.And, e, this.linearExpression));
return;
}
else
if (IsSupportedOperator(expr.op)) {
if (expr.left is NameNode && expr.right is ConstNode) {
ColumnInfo canColumn = (ColumnInfo)candidateColumns[((NameNode)(expr.left)).column.Ordinal];
canColumn.expr = (canColumn.expr == null ? expr : new BinaryNode(table, Operators.And, expr, canColumn.expr));
if (expr.op == Operators.EqualTo) {
canColumn.equalsOperator = true;
}
candidatesForBinarySearch = true;
return;
}
else
if (expr.right is NameNode && expr.left is ConstNode) {
ExpressionNode temp = expr.left;
expr.left = expr.right;
expr.right = temp;
switch(expr.op) {
case Operators.GreaterThen: expr.op = Operators.LessThen; break;
case Operators.LessThen: expr.op = Operators.GreaterThen; break;
case Operators.GreaterOrEqual: expr.op = Operators.LessOrEqual; break;
case Operators.LessOrEqual: expr.op = Operators.GreaterOrEqual; break;
default : break;
}
ColumnInfo canColumn = (ColumnInfo)candidateColumns[((NameNode)(expr.left)).column.Ordinal];
canColumn.expr = (canColumn.expr == null ? expr : new BinaryNode(table, Operators.And, expr, canColumn.expr));
if (expr.op == Operators.EqualTo) {
canColumn.equalsOperator = true;
}
candidatesForBinarySearch = true;
return;
}
}
this.linearExpression = (this.linearExpression == null ? expr : new BinaryNode(table, Operators.And, expr, this.linearExpression));
return;
}
private bool CompareSortIndexDesc(IndexField[] fields) {
if (fields.Length < IndexFields.Length)
return false;
int j=0;
for (int i = 0; i < fields.Length && j < IndexFields.Length; i++) {
if (fields[i] == IndexFields[j]) {
j++;
}
else {
ColumnInfo canColumn = candidateColumns[fields[i].Column.Ordinal];
if (!(canColumn != null && canColumn.equalsOperator))
return false;
}
}
return j == IndexFields.Length;
}
private bool FindSortIndex() {
index = null;
this.table.indexesLock.AcquireReaderLock(-1);
try{
int count = this.table.indexes.Count;
int rowsCount = this.table.Rows.Count;
for (int i = 0; i < count; i++) {
Index ndx = (Index)table.indexes[i];
if (ndx.RecordStates != recordStates)
continue;
if(!ndx.IsSharable) {
continue;
}
if (CompareSortIndexDesc(ndx.IndexFields)) {
index = ndx;
return true;
}
}
}
finally {
this.table.indexesLock.ReleaseReaderLock();
}
return false;
}
// Returns no. of columns that are matched
private int CompareClosestCandidateIndexDesc(IndexField[] fields) {
int count = (fields.Length < nCandidates ? fields.Length : nCandidates);
int i = 0;
for (; i < count; i++) {
ColumnInfo canColumn = candidateColumns[fields[i].Column.Ordinal];
if (canColumn == null || canColumn.expr == null) {
break;
}
else
if (!canColumn.equalsOperator) {
return i+1;
}
}
return i;
}
// Returns whether the found index (if any) is a sort index as well
private bool FindClosestCandidateIndex() {
index = null;
matchedCandidates = 0;
bool sortPriority = true;
this.table.indexesLock.AcquireReaderLock(-1);
try {
int count = this.table.indexes.Count;
int rowsCount = this.table.Rows.Count;
for (int i = 0; i < count; i++) {
Index ndx = (Index)table.indexes[i];
if (ndx.RecordStates != recordStates)
continue;
if(!ndx.IsSharable)
continue;
int match = CompareClosestCandidateIndexDesc(ndx.IndexFields);
if (match > matchedCandidates || (match == matchedCandidates && !sortPriority)) {
matchedCandidates = match;
index = ndx;
sortPriority = CompareSortIndexDesc(ndx.IndexFields);
if (matchedCandidates == nCandidates && sortPriority) {
return true;
}
}
}
}
finally {
this.table.indexesLock.ReleaseReaderLock();
}
return (index != null ? sortPriority : false);
}
// Initialize candidate columns to new columnInfo and leave all non candidate columns to null
private void InitCandidateColumns() {
nCandidates = 0;
candidateColumns = new ColumnInfo[this.table.Columns.Count];
if (this.rowFilter == null)
return;
DataColumn[] depColumns = rowFilter.GetDependency();
for (int i = 0; i < depColumns.Length; i++) {
if (depColumns[i].Table == this.table) {
candidateColumns[depColumns[i].Ordinal] = new ColumnInfo();
nCandidates++;
}
}
}
// Based on the required sorting and candidate columns settings, create a new index; Should be called only when there is no existing index to be reused
private void CreateIndex() {
if (index == null) {
if (nCandidates == 0) {
index = new Index(table, IndexFields, recordStates, null);
index.AddRef();
}
else {
int i;
int lenCanColumns = candidateColumns.Length;
int lenIndexDesc = IndexFields.Length;
bool equalsOperator = true;
for (i=0; i<lenCanColumns; i++) {
if (candidateColumns[i] != null) {
if (!candidateColumns[i].equalsOperator) {
equalsOperator = false;
break;
}
}
}
int j=0;
for (i=0; i < lenIndexDesc; i++) {
ColumnInfo candidateColumn = candidateColumns[IndexFields[i].Column.Ordinal];
if (candidateColumn != null) {
candidateColumn.flag = true;
j++;
}
}
int indexNotInCandidates = lenIndexDesc - j;
int candidatesNotInIndex = nCandidates - j;
IndexField[] ndxFields = new IndexField[nCandidates + indexNotInCandidates];
if (equalsOperator) {
j=0;
for (i=0; i<lenCanColumns; i++) {
if (candidateColumns[i] != null) {
ndxFields[j++] = new IndexField(this.table.Columns[i], isDescending: false);
candidateColumns[i].flag = false;// this means it is processed
}
}
for (i=0; i<lenIndexDesc; i++) {
ColumnInfo canColumn = candidateColumns[IndexFields[i].Column.Ordinal];
if (canColumn == null || canColumn.flag) { // if sort column is not a filter col , or not processed
ndxFields[j++] = IndexFields[i];
if (canColumn != null) {
canColumn.flag = false;
}
}
}
for(i = 0; i < candidateColumns.Length; i++) {
if (candidateColumns[i] != null) {
candidateColumns[i].flag = false;// same as before, it is false when it returns
}
}
// Debug.Assert(j == candidatesNotInIndex, "Whole ndxDesc should be filled!");
index = new Index(table, ndxFields, recordStates, null);
if (!IsOperatorIn(this.expression)) {
// if the expression contains an 'IN' operator, the index will not be shared
// therefore we do not need to index.AddRef, also table would track index consuming more memory until first write
index.AddRef();
}
matchedCandidates = nCandidates;
}
else {
for (i=0; i<lenIndexDesc; i++) {
ndxFields[i] = IndexFields[i];
ColumnInfo canColumn = candidateColumns[IndexFields[i].Column.Ordinal];
if (canColumn != null)
canColumn.flag = true;
}
j=i;
for (i=0; i<lenCanColumns; i++) {
if (candidateColumns[i] != null) {
if(!candidateColumns[i].flag) {
ndxFields[j++] = new IndexField(this.table.Columns[i], isDescending: false);
}
else {
candidateColumns[i].flag = false;
}
}
}
// Debug.Assert(j == nCandidates+indexNotInCandidates, "Whole ndxDesc should be filled!");
index = new Index(table, ndxFields, recordStates, null);
matchedCandidates = 0;
if (this.linearExpression != this.expression) {
IndexField[] fields = index.IndexFields;
while (matchedCandidates < j) { // Microsoft : j = index.IndexDesc.Length
ColumnInfo canColumn = candidateColumns[fields[matchedCandidates].Column.Ordinal];
if (canColumn == null || canColumn.expr == null)
break;
matchedCandidates++;
if (!canColumn.equalsOperator)
break;
}
}
for(i = 0; i < candidateColumns.Length; i++) {
if (candidateColumns[i] != null) {
candidateColumns[i].flag = false;// same as before, it is false when it returns
}
}
}
}
}
}
private bool IsOperatorIn(ExpressionNode enode) {
BinaryNode bnode = (enode as BinaryNode);
if (null != bnode) {
if (Operators.In == bnode.op ||
IsOperatorIn(bnode.right) ||
IsOperatorIn(bnode.left))
{
return true;
}
}
return false;
}
// Based on the current index and candidate columns settings, build the linear expression; Should be called only when there is atleast something for Binary Searching
private void BuildLinearExpression() {
int i;
IndexField[] fields = index.IndexFields;
int lenId = fields.Length;
Debug.Assert(matchedCandidates > 0 && matchedCandidates <= lenId, "BuildLinearExpression : Invalid Index");
for (i=0; i<matchedCandidates; i++) {
ColumnInfo canColumn = candidateColumns[fields[i].Column.Ordinal];
Debug.Assert(canColumn != null && canColumn.expr != null, "BuildLinearExpression : Must be a matched candidate");
canColumn.flag = true;
}
//this is invalid assert, assumption was that all equals operator exists at the begining of candidateColumns
// but with QFE 1704, this assumption is not true anymore
// Debug.Assert(matchedCandidates==1 || candidateColumns[matchedCandidates-1].equalsOperator, "BuildLinearExpression : Invalid matched candidates");
int lenCanColumns = candidateColumns.Length;
for (i=0; i<lenCanColumns; i++) {
if (candidateColumns[i] != null) {
if (!candidateColumns[i].flag) {
if (candidateColumns[i].expr != null) {
this.linearExpression = (this.linearExpression == null ? candidateColumns[i].expr : new BinaryNode(table, Operators.And, candidateColumns[i].expr, this.linearExpression));
}
}
else {
candidateColumns[i].flag = false;
}
}
}
// Debug.Assert(this.linearExpression != null, "BuildLinearExpression : How come there is nothing to search linearly");
}
public DataRow[] SelectRows() {
bool needSorting = true;
InitCandidateColumns();
if (this.expression is BinaryNode) {
AnalyzeExpression((BinaryNode)this.expression);
if (!candidatesForBinarySearch) {
this.linearExpression = this.expression;
}
if (this.linearExpression == this.expression) {
for (int i=0; i<candidateColumns.Length; i++) {
if (candidateColumns[i] != null) {
candidateColumns[i].equalsOperator = false;
candidateColumns[i].expr = null;
}
}
}
else {
needSorting = !FindClosestCandidateIndex();
}
}
else {
this.linearExpression = this.expression;
}
if (index == null && (IndexFields.Length > 0 || this.linearExpression == this.expression)) {
needSorting = !FindSortIndex();
}
if (index == null) {
CreateIndex();
needSorting = false;
}
if (index.RecordCount == 0)
return table.NewRowArray(0);
Range range;
if (matchedCandidates == 0) { // Microsoft : Either dont have rowFilter or only linear search expression
range = new Range(0, index.RecordCount-1);
Debug.Assert(!needSorting, "What are we doing here if no real reuse of this index ?");
this.linearExpression = this.expression;
return GetLinearFilteredRows(range);
}
else {
range = GetBinaryFilteredRecords();
if (range.Count == 0)
return table.NewRowArray(0);
if (matchedCandidates < nCandidates) {
BuildLinearExpression();
}
if (!needSorting) {
return GetLinearFilteredRows(range);
}
else {
this.records = GetLinearFilteredRecords(range);
this.recordCount = this.records.Length;
if (this.recordCount == 0)
return table.NewRowArray(0);
Sort(0, this.recordCount-1);
return GetRows();
}
}
}
public DataRow[] GetRows() {
DataRow[] newRows = table.NewRowArray(recordCount);
for (int i = 0; i < newRows.Length; i++) {
newRows[i] = table.recordManager[records[i]];
}
return newRows;
}
private bool AcceptRecord(int record) {
DataRow row = table.recordManager[record];
if (row == null)
return true;
//
DataRowVersion version = DataRowVersion.Default;
if (row.oldRecord == record) {
version = DataRowVersion.Original;
}
else if (row.newRecord == record) {
version = DataRowVersion.Current;
}
else if (row.tempRecord == record) {
version = DataRowVersion.Proposed;
}
object val = this.linearExpression.Eval(row, version);
bool result;
try {
result = DataExpression.ToBoolean(val);
}
catch (Exception e) {
//
if (!ADP.IsCatchableExceptionType(e)) {
throw;
}
throw ExprException.FilterConvertion(this.rowFilter.Expression);
}
return result;
}
private int Eval(BinaryNode expr, DataRow row, DataRowVersion version) {
if (expr.op == Operators.And) {
int lResult = Eval((BinaryNode)expr.left,row,version);
if (lResult != 0)
return lResult;
int rResult = Eval((BinaryNode)expr.right,row,version);
if (rResult != 0)
return rResult;
return 0;
}
long c = 0;
object vLeft = expr.left.Eval(row, version);
if (expr.op != Operators.Is && expr.op != Operators.IsNot) {
object vRight = expr.right.Eval(row, version);
bool isLConst = (expr.left is ConstNode);
bool isRConst = (expr.right is ConstNode);
if ((vLeft == DBNull.Value)||(expr.left.IsSqlColumn && DataStorage.IsObjectSqlNull(vLeft)))
return -1;
if ((vRight == DBNull.Value)||(expr.right.IsSqlColumn && DataStorage.IsObjectSqlNull(vRight)))
return 1;
StorageType leftType = DataStorage.GetStorageType(vLeft.GetType());
if (StorageType.Char == leftType) {
if ((isRConst)||(!expr.right.IsSqlColumn))
vRight = Convert.ToChar(vRight, table.FormatProvider);
else
vRight = SqlConvert.ChangeType2(vRight, StorageType.Char, typeof(char), table.FormatProvider);
}
StorageType rightType = DataStorage.GetStorageType(vRight.GetType());
StorageType resultType;
if (expr.left.IsSqlColumn || expr.right.IsSqlColumn) {
resultType = expr.ResultSqlType(leftType, rightType, isLConst, isRConst, expr.op);
}
else {
resultType = expr.ResultType(leftType, rightType, isLConst, isRConst, expr.op);
}
if (StorageType.Empty == resultType) {
expr.SetTypeMismatchError(expr.op, vLeft.GetType(), vRight.GetType());
}
// if comparing a Guid column value against a string literal
// use InvariantCulture instead of DataTable.Locale because in the Danish related cultures
// sorting a Guid as a string has different results than in Invariant and English related cultures.
// This fix is restricted to DataTable.Select("GuidColumn = 'string literal'") types of queries
NameNode namedNode = null;
System.Globalization.CompareInfo comparer =
((isLConst && !isRConst && (leftType == StorageType.String) && (rightType == StorageType.Guid) && (null != (namedNode = expr.right as NameNode)) && (namedNode.column.DataType == typeof(Guid))) ||
(isRConst && !isLConst && (rightType == StorageType.String) && (leftType == StorageType.Guid) && (null != (namedNode = expr.left as NameNode)) && (namedNode.column.DataType == typeof(Guid))))
? System.Globalization.CultureInfo.InvariantCulture.CompareInfo : null;
c = expr.BinaryCompare(vLeft, vRight, resultType, expr.op, comparer);
}
switch(expr.op) {
case Operators.EqualTo: c = (c == 0 ? 0 : c < 0 ? -1 : 1); break;
case Operators.GreaterThen: c = (c > 0 ? 0 : -1); break;
case Operators.LessThen: c = (c < 0 ? 0 : 1); break;
case Operators.GreaterOrEqual: c = (c >= 0 ? 0 : -1); break;
case Operators.LessOrEqual: c = (c <= 0 ? 0 : 1); break;
case Operators.Is: c = (vLeft == DBNull.Value ? 0 : -1); break;
case Operators.IsNot: c = (vLeft != DBNull.Value ? 0 : 1); break;
default: Debug.Assert(true, "Unsupported Binary Search Operator!"); break;
}
return (int)c;
}
private int Evaluate(int record) {
DataRow row = table.recordManager[record];
if (row == null)
return 0;
//
DataRowVersion version = DataRowVersion.Default;
if (row.oldRecord == record) {
version = DataRowVersion.Original;
}
else if (row.newRecord == record) {
version = DataRowVersion.Current;
}
else if (row.tempRecord == record) {
version = DataRowVersion.Proposed;
}
IndexField[] fields = index.IndexFields;
for (int i=0; i < matchedCandidates; i++) {
int columnOrdinal = fields[i].Column.Ordinal;
Debug.Assert(candidateColumns[columnOrdinal] != null, "How come this is not a candidate column");
Debug.Assert(candidateColumns[columnOrdinal].expr != null, "How come there is no associated expression");
int c = Eval(candidateColumns[columnOrdinal].expr, row, version);
if (c != 0)
return fields[i].IsDescending ? -c : c;
}
return 0;
}
private int FindFirstMatchingRecord() {
int rec = -1;
int lo = 0;
int hi = index.RecordCount - 1;
while (lo <= hi) {
int i = lo + hi >> 1;
int recNo = index.GetRecord(i);
int c = Evaluate(recNo);
if (c == 0) { rec = i; }
if (c < 0) lo = i + 1;
else hi = i - 1;
}
return rec;
}
private int FindLastMatchingRecord(int lo) {
int rec = -1;
int hi = index.RecordCount - 1;
while (lo <= hi) {
int i = lo + hi >> 1;
int recNo = index.GetRecord(i);
int c = Evaluate(recNo);
if (c == 0) { rec = i; }
if (c <= 0) lo = i + 1;
else hi = i - 1;
}
return rec;
}
private Range GetBinaryFilteredRecords() {
if (matchedCandidates == 0) {
return new Range(0, index.RecordCount-1);
}
Debug.Assert(matchedCandidates <= index.IndexFields.Length, "GetBinaryFilteredRecords : Invalid Index");
int lo = FindFirstMatchingRecord();
if (lo == -1) {
return new Range();
}
int hi = FindLastMatchingRecord(lo);
Debug.Assert (lo <= hi, "GetBinaryFilteredRecords : Invalid Search Results");
return new Range(lo, hi);
}
private int[] GetLinearFilteredRecords(Range range) {
if (this.linearExpression == null) {
int[] resultRecords = new int[range.Count];
RBTree<int>.RBTreeEnumerator iterator = index.GetEnumerator(range.Min);
for (int i = 0; i < range.Count && iterator.MoveNext(); i++) {
resultRecords[i] = iterator.Current;
}
return resultRecords;
}
else {
List<int> matchingRecords = new List<int>();
RBTree<int>.RBTreeEnumerator iterator = index.GetEnumerator(range.Min);
for (int i = 0; i < range.Count && iterator.MoveNext(); i++) {
if (AcceptRecord(iterator.Current)) {
matchingRecords.Add(iterator.Current);
}
}
return matchingRecords.ToArray();
}
}
private DataRow[] GetLinearFilteredRows(Range range) {
DataRow[] resultRows;
if (this.linearExpression == null) {
return index.GetRows(range);
}
List<DataRow> matchingRows = new List<DataRow>();
RBTree<int>.RBTreeEnumerator iterator = index.GetEnumerator(range.Min);
for (int i = 0; i < range.Count && iterator.MoveNext(); i++) {
if (AcceptRecord(iterator.Current)) {
matchingRows.Add(table.recordManager[iterator.Current]);
}
}
resultRows = table.NewRowArray(matchingRows.Count);
matchingRows.CopyTo(resultRows);
return resultRows;
}
private int CompareRecords(int record1, int record2) {
int lenIndexDesc = IndexFields.Length;
for (int i = 0; i < lenIndexDesc; i++) {
int c = IndexFields[i].Column.Compare(record1, record2);
if (c != 0) {
if (IndexFields[i].IsDescending) c = -c;
return c;
}
}
long id1 = table.recordManager[record1] == null? 0: table.recordManager[record1].rowID;
long id2 = table.recordManager[record2] == null ? 0 : table.recordManager[record2].rowID;
int diff = (id1 < id2) ? -1 : ((id2 < id1) ? 1 : 0);
// if they're two records in the same row, we need to be able to distinguish them.
if (diff == 0 && record1 != record2 &&
table.recordManager[record1] != null && table.recordManager[record2] != null) {
id1 = (int)table.recordManager[record1].GetRecordState(record1);
id2 = (int)table.recordManager[record2].GetRecordState(record2);
diff = (id1 < id2) ? -1 : ((id2 < id1) ? 1 : 0);
}
return diff;
}
private void Sort(int left, int right) {
int i, j;
int record;
do {
i = left;
j = right;
record = records[i + j >> 1];
do {
while (CompareRecords(records[i], record) < 0) i++;
while (CompareRecords(records[j], record) > 0) j--;
if (i <= j) {
int r = records[i];
records[i] = records[j];
records[j] = r;
i++;
j--;
}
} while (i <= j);
if (left < j) Sort(left, j);
left = i;
} while (i < right);
}
}
}
|