Class KnownRangeHasher

NON-GENERALIZED hashing algorithm for Point instances that calculates a hash, assuming a known minimum and maximum extent of the Points being hashed.

Inheritance
Object
KnownRangeHasher
Namespace: SadRogue.Primitives.PointHashers
Assembly: TheSadRogue.Primitives.dll
Syntax
public class KnownRangeHasher : EqualityComparer<Point>
Remarks

This is NOT an efficient generalized hashing algorithm; it generates a hash code using the assumption of a "maximum range" of x/y values in which all the points given to it to hash fall. It simply normalizes the points to a range of (0, 0), to (x_1, y_1), then hashes them via a simple call to ToIndex(Int32). The algorithm WILL still function on points outside of the min/max extents; however it will start to generate more collisions.

This algorithm is nonetheless useful in some cases; the assumption that points will fall from (minX, minY) to some known max width/height is fairly common (as it could apply to any fixed-size grid). Since this algorithm can be significantly faster to compute than fully generalized algorithms, it can be useful for these cases.

Constructors

KnownRangeHasher(Point, Point)

Creates a new instance of the comparison/hashing algorithm implementation.

Declaration
public KnownRangeHasher(Point minExtent, Point maxExtent)
Parameters
Type Name Description
Point minExtent

Point whose x and y values constitute the minimum x/y values that will generally be encountered in Point instances that are hashed by this algorithm.
Point maxExtent

Point whose x and y values constitute the maximum x/y values that will generally be encountered in Point instances that are hashed by this algorithm.

KnownRangeHasher(Point, Int32)

Creates a new instance of the comparison/hashing algorithm implementation.

Declaration
public KnownRangeHasher(Point minExtent, int boundsWidth)
Parameters
Type Name Description
Point minExtent

Point whose x and y values constitute the minimum x/y values that will generally be encountered in Point instances that are hashed by this algorithm.
Int32 boundsWidth

Width of the bounds that will generally encompass Points hashed by this hashing algorithm.

KnownRangeHasher(Rectangle)

Creates a new instance of the comparison/hashing algorithm implementation.

Declaration
public KnownRangeHasher(Rectangle bounds)
Parameters
Type Name Description
Rectangle bounds

Bounds encompassing the area which points generally hashed by this algorithm will reside within.

Fields

BoundsWidth

Width of the area which encompasses points which will generally be hashed by this algorithm, starting at MinExtent.

Declaration
public readonly int BoundsWidth
Field Value
Type Description
Int32

MinExtent

Minimum x/y values that will generally occur in points hashed by this instance.

Declaration
public readonly Point MinExtent
Field Value
Type Description
Point

Methods

Equals(Point, Point)

Declaration
public override bool Equals(Point x, Point y)
Parameters
Type Name Description
Point x
Point y
Returns
Type Description
Boolean

GetHashCode(Point)

Declaration
public override int GetHashCode(Point p)
Parameters
Type Name Description
Point p
Returns
Type Description
Int32

Extension Methods