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turbonss/cxxmph/trigraph.cc

60 lines
1.7 KiB
C++

#include <cassert>
#include <limits>
#include "trigraph.h"
using std::vector;
namespace {
static const cmph_uint8 kInvalidEdge = std::numeric_limits<cmph_uint8>::max();
}
namespace cxxmph {
TriGraph::TriGraph(cmph_uint32 nedges, cmph_uint32 nvertices)
: nedges_(0),
edges_(nedges),
first_edge_(nvertices, kInvalidEdge),
vertex_degree_(nvertices, 0) { }
void TriGraph::ExtractEdgesAndClear(vector<Edge>* edges) {
vector<Edge>().swap(next_edge_);
vector<cmph_uint32>().swap(first_edge_);
vector<cmph_uint8>().swap(vertex_degree_);
nedges_ = 0;
edges->swap(edges_);
}
void TriGraph::AddEdge(const Edge& edge) {
edges_[nedges_] = edge;
next_edge_[nedges_] = Edge(
first_edge_[edge[0]], first_edge_[edge[1]], first_edge_[edge[2]]);
first_edge_[edge[0]] = first_edge_[edge[1]] = first_edge_[edge[2]] = nedges_;
++vertex_degree_[edge[0]];
++vertex_degree_[edge[1]];
++vertex_degree_[edge[2]];
++nedges_;
}
void TriGraph::RemoveEdge(cmph_uint32 current_edge) {
cmph_uint32 vertex, edge1, edge2;
for (int i = 0; i < 3; ++i) {
cmph_uint32 vertex = edges_[current_edge][i];
cmph_uint32 edge1 = first_edge_[vertex];
cmph_uint32 edge2 = kInvalidEdge;
cmph_uint32 j = 0;
while (edge1 != current_edge && edge1 != kInvalidEdge) {
edge2 = edge1;
if (edges_[edge1][0] == vertex) j = 0;
else if (edges_[edge1][1] == vertex) j = 1;
else j = 2;
edge1 = next_edge_[edge1][j];
}
assert(edge1 != kInvalidEdge);
if (edge2 != kInvalidEdge) next_edge_[edge2][j] = next_edge_[edge1][i];
else first_edge_[vertex] = next_edge_[edge1][i];
--vertex_degree_[vertex];
}
}
} // namespace cxxmph