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CompressedSparseRowGraph.cs
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257 lines (222 loc) · 7.5 KB
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics.Contracts;
using System.Diagnostics;
namespace QuickGraph
{
/// <summary>
/// Directed graph representation using a Compressed Sparse Row representation
/// (http://www.cs.utk.edu/~dongarra/etemplates/node373.html)
/// </summary>
/// <typeparam name="TVertex">type of the vertices</typeparam>
#if !SILVERLIGHT
[Serializable]
#endif
[DebuggerDisplay("VertexCount = {VertexCount}, EdgeCount = {EdgeCount}")]
public sealed class CompressedSparseRowGraph<TVertex>
: IVertexSet<TVertex>
, IEdgeSet<TVertex, SEquatableEdge<TVertex>>
, IVertexListGraph<TVertex, SEquatableEdge<TVertex>>
#if !SILVERLIGHT
, ICloneable
#endif
{
#if !SILVERLIGHT
[Serializable]
#endif
struct Range
{
public readonly int Start;
public readonly int End;
public Range(int start, int end)
{
Contract.Requires(start >= 0);
Contract.Requires(start <= end);
Contract.Ensures(Contract.ValueAtReturn(out this).Start == start);
Contract.Ensures(Contract.ValueAtReturn(out this).End == end);
this.Start = start;
this.End = end;
}
public int Length
{
get {
Contract.Ensures(Contract.Result<int>() >= 0);
return this.End - this.Start;
}
}
}
readonly Dictionary<TVertex, Range> outEdgeStartRanges;
readonly TVertex[] outEdges;
private CompressedSparseRowGraph(
Dictionary<TVertex, Range> outEdgeStartRanges,
TVertex[] outEdges
)
{
Contract.Requires(outEdgeStartRanges != null);
Contract.Requires(outEdges != null);
this.outEdgeStartRanges = outEdgeStartRanges;
this.outEdges = outEdges;
}
public static CompressedSparseRowGraph<TVertex> FromGraph<TEdge>(
IVertexAndEdgeListGraph<TVertex, TEdge> visitedGraph
)
where TEdge : IEdge<TVertex>
{
Contract.Requires(visitedGraph != null);
Contract.Ensures(Contract.Result<CompressedSparseRowGraph<TVertex>>() != null);
var outEdgeStartRanges = new Dictionary<TVertex, Range>(visitedGraph.VertexCount);
var outEdges = new TVertex[visitedGraph.EdgeCount];
int start = 0;
int end = 0;
int index = 0;
foreach (var vertex in visitedGraph.Vertices)
{
end = start + visitedGraph.OutDegree(vertex);
var range = new Range(start, end);
outEdgeStartRanges.Add(vertex, range);
foreach (var edge in visitedGraph.OutEdges(vertex))
outEdges[index++] = edge.Target;
Contract.Assert(index == end);
}
Contract.Assert(index == outEdges.Length);
return new CompressedSparseRowGraph<TVertex>(
outEdgeStartRanges,
outEdges);
}
public bool IsVerticesEmpty
{
get { return this.outEdgeStartRanges.Count > 0; }
}
public int VertexCount
{
get { return this.outEdgeStartRanges.Count; }
}
public IEnumerable<TVertex> Vertices
{
get { return this.outEdgeStartRanges.Keys; }
}
public bool ContainsVertex(TVertex vertex)
{
return this.outEdgeStartRanges.ContainsKey(vertex);
}
public int EdgeCount
{
get { return this.outEdges.Length; }
}
public bool IsEdgesEmpty
{
get { return this.outEdges.Length > 0; }
}
public IEnumerable<SEquatableEdge<TVertex>> Edges
{
get
{
foreach (var kv in this.outEdgeStartRanges)
{
var source = kv.Key;
var range = kv.Value;
for (int i = range.Start; i < range.End; ++i)
{
var target = this.outEdges[i];
yield return new SEquatableEdge<TVertex>(source, target);
}
}
}
}
public bool ContainsEdge(SEquatableEdge<TVertex> edge)
{
return ContainsEdge(edge.Source, edge.Target);
}
public bool ContainsEdge(TVertex source, TVertex target)
{
Range range;
if (this.outEdgeStartRanges.TryGetValue(source, out range))
{
for (int i = range.Start; i < range.End; ++i)
if (this.outEdges[i].Equals(target))
return true;
}
return false;
}
public bool TryGetEdges(
TVertex source,
TVertex target,
out IEnumerable<SEquatableEdge<TVertex>> edges)
{
if (this.ContainsEdge(source, target))
{
edges = new SEquatableEdge<TVertex>[] { new SEquatableEdge<TVertex>(source, target) };
return true;
}
edges = null;
return false;
}
public bool TryGetEdge(
TVertex source,
TVertex target,
out SEquatableEdge<TVertex> edge)
{
if (this.ContainsEdge(source, target))
{
edge = new SEquatableEdge<TVertex>(source, target);
return true;
}
edge = default(SEquatableEdge<TVertex>);
return false;
}
public bool IsOutEdgesEmpty(TVertex v)
{
return this.outEdgeStartRanges[v].Length == 0;
}
public int OutDegree(TVertex v)
{
return this.outEdgeStartRanges[v].Length;
}
public IEnumerable<SEquatableEdge<TVertex>> OutEdges(TVertex v)
{
var range = this.outEdgeStartRanges[v];
for(int i = range.Start;i<range.End;++i)
yield return new SEquatableEdge<TVertex>(v, this.outEdges[i]);
}
public bool TryGetOutEdges(TVertex v, out IEnumerable<SEquatableEdge<TVertex>> edges)
{
var range = this.outEdgeStartRanges[v];
if (range.Length > 0)
{
edges = this.OutEdges(v);
return false;
}
edges = null;
return false;
}
public SEquatableEdge<TVertex> OutEdge(TVertex v, int index)
{
var range = this.outEdgeStartRanges[v];
var targetIndex = range.Start + index;
Contract.Assert(targetIndex < range.End);
return new SEquatableEdge<TVertex>(v, this.outEdges[targetIndex]);
}
public bool IsDirected
{
get { return true; }
}
public bool AllowParallelEdges
{
get { return false; }
}
public CompressedSparseRowGraph<TVertex> Clone()
{
var ranges = new Dictionary<TVertex, Range>(this.outEdgeStartRanges);
var edges = (TVertex[])this.outEdges.Clone();
return new CompressedSparseRowGraph<TVertex>(ranges, edges);
}
#if !SILVERLIGHT
object ICloneable.Clone()
{
return this.Clone();
}
#endif
}
}