public override IEnumerable<int> SelectRange(IndexRange[] ranges)
{
int setSize = Table.RowCount;
// If no items in the set return an empty set
if (setSize == 0)
return new List<int>(0);
var checker = new RangeChecker(this, ranges);
return checker.Resolve();
}
public override IEnumerable<int> SelectRange(IndexRange[] ranges)
{
// If no items in the set return an empty set
if (Count == 0)
return new List<int>(0);
IEnumerable<int> list = null;
foreach (var range in ranges) {
list = AddRange(range, list);
}
if (list == null)
return new List<int>(0);
return list;
}
private static IndexRange IntersectOn(IndexRange range, SqlExpressionType op, Field value, bool nullCheck)
{
var start = range.StartValue;
var startPosition = range.StartOffset;
var end = range.EndValue;
var endPosition = range.EndOffset;
bool inclusive = op == SqlExpressionType.Is ||
op == SqlExpressionType.Equal ||
op == SqlExpressionType.GreaterOrEqualThan ||
op == SqlExpressionType.SmallerOrEqualThan;
if (op == SqlExpressionType.Is ||
op == SqlExpressionType.Equal ||
op == SqlExpressionType.GreaterThan ||
op == SqlExpressionType.GreaterOrEqualThan) {
// With this operator, NULL values must return null.
if (nullCheck && value.IsNull) {
return IndexRange.Null;
}
if (start.Equals(IndexRange.FirstInSet)) {
start = value;
startPosition = inclusive ? RangeFieldOffset.FirstValue : RangeFieldOffset.AfterLastValue;
} else {
int c = value.CompareTo(start);
if ((c == 0 && startPosition == RangeFieldOffset.FirstValue) || c > 0) {
start = value;
startPosition = inclusive ? RangeFieldOffset.FirstValue : RangeFieldOffset.AfterLastValue;
}
}
}
if (op == SqlExpressionType.Is ||
op == SqlExpressionType.Equal ||
op == SqlExpressionType.SmallerThan ||
op == SqlExpressionType.SmallerOrEqualThan) {
// With this operator, NULL values must return null.
if (nullCheck && value.IsNull) {
return IndexRange.Null;
}
// If start is first in set, then we have to change it to after NULL
if (nullCheck && start.Equals(IndexRange.FirstInSet)) {
start = Field.Null();
startPosition = RangeFieldOffset.AfterLastValue;
}
if (end.Equals(IndexRange.LastInSet)) {
end = value;
endPosition = inclusive ? RangeFieldOffset.LastValue : RangeFieldOffset.BeforeFirstValue;
} else {
int c = value.CompareTo(end);
if ((c == 0 && endPosition == RangeFieldOffset.LastValue) || c < 0) {
end = value;
endPosition = inclusive ? RangeFieldOffset.LastValue : RangeFieldOffset.BeforeFirstValue;
}
}
}
// If start and end are not null types (if either are, then it means it
// is a placeholder value meaning start or end of set).
if (!start.Equals(IndexRange.FirstInSet) &&
!end.Equals(IndexRange.LastInSet)) {
// If start is higher than end, return null
int c = start.CompareTo(end);
if ((c == 0 && (startPosition == RangeFieldOffset.AfterLastValue ||
endPosition == RangeFieldOffset.BeforeFirstValue)) ||
c > 0) {
return IndexRange.Null;
}
}
// The new intersected range
return new IndexRange(startPosition, start, endPosition, end);
}
/// <summary>
/// Returns true if the two SelectableRange ranges intersect.
/// </summary>
private static bool IntersectedBy(IndexRange range1, IndexRange range2)
{
var startFlag1 = range1.StartOffset;
var start1 = range1.StartValue;
var endFlag1 = range1.EndOffset;
var end1 = range1.EndValue;
var startFlag2 = range2.StartOffset;
var start2 = range2.StartValue;
var endFlag2 = range2.EndOffset;
var end2 = range2.EndValue;
var startCell1 = start1.Equals(IndexRange.FirstInSet) ? null : start1;
var endCell1 = end1.Equals(IndexRange.LastInSet) ? null : end1;
var startCell2 = start2.Equals(IndexRange.FirstInSet) ? null : start2;
var endCell2 = end2.Equals(IndexRange.LastInSet) ? null : end2;
bool intersect1 = false;
if (startCell1 != null && endCell2 != null) {
int c = startCell1.CompareTo(endCell2);
if (c < 0 ||
(c == 0 && (startFlag1 == RangeFieldOffset.FirstValue ||
endFlag2 == RangeFieldOffset.LastValue))) {
intersect1 = true;
}
} else {
intersect1 = true;
}
bool intersect2 = false;
if (startCell2 != null && endCell1 != null) {
int c = startCell2.CompareTo(endCell1);
if (c < 0 ||
(c == 0 && (startFlag2 == RangeFieldOffset.FirstValue ||
endFlag1 == RangeFieldOffset.LastValue))) {
intersect2 = true;
}
} else {
intersect2 = true;
}
return (intersect1 && intersect2);
}
/// <summary>
/// Alters the first range so it encompasses the second range.
/// </summary>
/// <remarks>
/// This assumes that range1 intersects range2.
/// </remarks>
private static IndexRange ChangeRangeSizeToEncompass(IndexRange range1, IndexRange range2)
{
var startPosition1 = range1.StartOffset;
var start1 = range1.StartValue;
var endPosition1 = range1.EndOffset;
var end1 = range1.EndValue;
var startPosition2 = range2.StartOffset;
var start2 = range2.StartValue;
var endPosition2 = range2.EndOffset;
var end2 = range2.EndValue;
if (!start1.Equals(IndexRange.FirstInSet)) {
if (!start2.Equals(IndexRange.FirstInSet)) {
var cell = start1;
int c = cell.CompareTo(start2);
if (c > 0 ||
c == 0 && startPosition1 == RangeFieldOffset.AfterLastValue &&
startPosition2 == RangeFieldOffset.FirstValue) {
start1 = start2;
startPosition1 = startPosition2;
}
} else {
start1 = start2;
startPosition1 = startPosition2;
}
}
if (!end1.Equals(IndexRange.LastInSet)) {
if (!end2.Equals(IndexRange.LastInSet)) {
var cell = end1;
int c = cell.CompareTo(end2);
if (c < 0 ||
c == 0 && endPosition1 == RangeFieldOffset.BeforeFirstValue &&
endPosition2 == RangeFieldOffset.LastValue) {
end1 = end2;
endPosition1 = endPosition2;
}
} else {
end1 = end2;
endPosition1 = endPosition2;
}
}
return new IndexRange(startPosition1, start1, endPosition1, end1);
}
private IEnumerable<int> AddRange(IndexRange range, IEnumerable<int> list)
{
// Select the range specified.
var startFlag = range.StartOffset;
var start = range.StartValue;
var endFlag = range.EndOffset;
var end = range.EndValue;
int r1 = PositionOfRangePoint(startFlag, start);
int r2 = PositionOfRangePoint(endFlag, end);
if (r2 < r1)
return list;
// Add the range to the set
return AddRange(r1, r2, list);
}
/// <summary>
/// Set up a range.
/// </summary>
/// <param name="i"></param>
/// <param name="range"></param>
private void SetupRange(int i, IndexRange range)
{
var l = range.StartValue;
var lf = range.StartOffset;
var u = range.EndValue;
var uf = range.EndOffset;
// Handle lower first
if (l.Equals(IndexRange.FirstInSet) &&
lf.Equals(RangeFieldOffset.FirstValue)) {
// Special case no lower check
lowerFlags[i] = NoCheck;
} else {
if (lf.Equals(RangeFieldOffset.FirstValue)) {
lowerFlags[i] = CheckLesserEqualOrGreaterEqual; // >=
} else if (lf.Equals(RangeFieldOffset.AfterLastValue)) {
lowerFlags[i] = CheckLesserOrGreater; // >
} else {
throw new InvalidOperationException("Incorrect lower flag.");
}
lowerCells[i] = ResolveCell(l);
}
// Now handle upper
if (u.Equals(IndexRange.LastInSet) &&
uf.Equals(RangeFieldOffset.LastValue)) {
// Special case no upper check
upperFlags[i] = NoCheck;
} else {
if (uf.Equals(RangeFieldOffset.LastValue)) {
upperFlags[i] = CheckLesserEqualOrGreaterEqual; // <=
} else if (uf.Equals( RangeFieldOffset.BeforeFirstValue)) {
upperFlags[i] = CheckLesserOrGreater; // <
} else {
throw new InvalidOperationException("Incorrect upper flag.");
}
upperCells[i] = ResolveCell(u);
}
}
public RangeChecker(BlindSearchIndex scheme, IndexRange[] ranges)
{
this.scheme = scheme;
int size = ranges.Length;
lowerFlags = new byte[size];
upperFlags = new byte[size];
lowerCells = new DataObject[size];
upperCells = new DataObject[size];
for (int i = 0; i < ranges.Length; ++i) {
SetupRange(i, ranges[i]);
}
}
public static ITable SelectRange(this ITable thisTable, ObjectName columnName, IndexRange[] ranges)
{
// If this table is empty then there is no range to select so
// trivially return this object.
if (thisTable.RowCount == 0)
return thisTable;
// Are we selecting a black or null range?
if (ranges == null || ranges.Length == 0)
// Yes, so return an empty table
return thisTable.EmptySelect();
// Are we selecting the entire range?
if (ranges.Length == 1 &&
ranges[0].Equals(IndexRange.FullRange))
// Yes, so return this table.
return thisTable;
// Must be a non-trivial range selection.
// Find the column index of the column selected
int column = thisTable.IndexOfColumn(columnName);
if (column == -1) {
throw new Exception(
"Unable to find the column given to select the range of: " +
columnName.Name);
}
// Select the range
var rows = thisTable.SelectRowsRange(column, ranges);
// Make a new table with the range selected
var result = new VirtualTable(thisTable, rows.ToArray());
// We know the new set is ordered by the column.
result.SortColumn = column;
return result;
}
public static IEnumerable<int> SelectRowsRange(this ITable table, int column, IndexRange[] ranges)
{
return table.GetIndex(column).SelectRange(ranges);
}
public override IEnumerable<int> SelectRange(IndexRange[] ranges)
{
throw new NotImplementedException();
}
