Merge pull request #76 from Tochemey/master

feat: add Order and Size methods to the graph

base.go

@@ -1,5 +1,7 @@
 package gograph
 
+import "sync/atomic"
+
 // baseGraph represents a basic implementation of Graph interface. It
 // supports multiple types of graph.
 //
@@ -16,6 +18,9 @@ type baseGraph[T comparable] struct {
 	edges map[T]map[T]*Edge[T]
 
 	properties GraphProperties
+
+	verticesCount uint32
+	edgesCount    uint32
 }
 
 func newBaseGraph[T comparable](properties GraphProperties) *baseGraph[T] {
@@ -38,6 +43,7 @@ func (g *baseGraph[T]) addToEdgeMap(from, to *Vertex[T], options ...EdgeOptionFu
 		g.edges[from.label][to.label] = edge
 	}
 
+	atomic.AddUint32(&g.edgesCount, 1)
 	return edge
 }
 
@@ -133,6 +139,8 @@ func (g *baseGraph[T]) addVertex(v *Vertex[T]) *Vertex[T] {
 	}
 
 	g.vertices[v.label] = v
+	atomic.AddUint32(&g.verticesCount, 1)
+
 	return v
 }
 
@@ -294,6 +302,7 @@ func (g *baseGraph[T]) removeEdge(edge *Edge[T]) {
 		if len(destMap) == 0 {
 			delete(g.edges, edge.source.label)
 		}
+		atomic.AddUint32(&g.edgesCount, ^(uint32(1) - 1))
 	}
 }
 
@@ -381,6 +390,7 @@ func (g *baseGraph[T]) removeVertex(in *Vertex[T]) {
 
 	delete(g.edges, v.label)
 	delete(g.vertices, v.label)
+	atomic.AddUint32(&g.verticesCount, ^(uint32(1) - 1))
 }
 
 // ContainsEdge returns 'true' if and only if this graph contains an edge
@@ -431,3 +441,13 @@ func (g *baseGraph[T]) AllEdges() []*Edge[T] {
 
 	return out
 }
+
+// Order returns the number of vertices in the graph.
+func (g *baseGraph[T]) Order() uint32 {
+	return atomic.LoadUint32(&g.verticesCount)
+}
+
+// Size returns the number of edges in the graph
+func (g *baseGraph[T]) Size() uint32 {
+	return atomic.LoadUint32(&g.edgesCount)
+}

base_test.go

@@ -149,6 +149,12 @@ func TestBaseGraph_AddEdgeAcyclic(t *testing.T) {
 	g.AddVertex(v2)
 	g.AddVertex(v3)
 
+	expectedVerticesCount := uint32(3)
+	actual := g.Order()
+	if actual != expectedVerticesCount {
+		t.Errorf("expected (%d) but got (%d)", expectedVerticesCount, actual)
+	}
+
 	// Add edges from 1 to 2 and from 2 to 3
 	_, err := g.AddEdge(v1, v2)
 	if err != nil {
@@ -165,6 +171,12 @@ func TestBaseGraph_AddEdgeAcyclic(t *testing.T) {
 	if err == nil {
 		t.Error("Expected error, but got none")
 	}
+
+	expectedEdgesCount := uint32(2)
+	actual = g.Size()
+	if actual != expectedEdgesCount {
+		t.Errorf("expected (%d) but got (%d)", expectedEdgesCount, actual)
+	}
 }
 
 func TestBaseGraph_AddEdgeWeighted(t *testing.T) {

graph.go

@@ -113,6 +113,12 @@ type Graph[T comparable] interface {
 	//
 	// If the specified vertex is nil, returns 'false'.
 	ContainsVertex(v *Vertex[T]) bool
+
+	// Order returns the number of vertices in the graph.
+	Order() uint32
+
+	// Size returns the number of edges in the graph
+	Size() uint32
 }
 
 // New creates a new instance of base graph that implemented the Graph interface.