97 lines
2.0 KiB
Go
97 lines
2.0 KiB
Go
package main
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type termKey struct {
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termType string
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key string
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}
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type graphAccumulator struct {
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includeBNodes bool
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nodeLimit int
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nodeIDByKey map[termKey]uint32
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nodes []Node
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edges []Edge
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preds *PredicateDict
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}
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func newGraphAccumulator(nodeLimit int, includeBNodes bool, edgeCapHint int, preds *PredicateDict) *graphAccumulator {
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if preds == nil {
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preds = NewPredicateDict(nil)
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}
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return &graphAccumulator{
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includeBNodes: includeBNodes,
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nodeLimit: nodeLimit,
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nodeIDByKey: make(map[termKey]uint32),
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nodes: make([]Node, 0, min(nodeLimit, 4096)),
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edges: make([]Edge, 0, min(edgeCapHint, 4096)),
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preds: preds,
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}
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}
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func (g *graphAccumulator) getOrAddNode(term sparqlTerm) (uint32, bool) {
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if term.Type == "" || term.Value == "" {
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return 0, false
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}
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if term.Type == "literal" {
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return 0, false
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}
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var key termKey
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var node Node
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if term.Type == "bnode" {
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if !g.includeBNodes {
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return 0, false
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}
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key = termKey{termType: "bnode", key: term.Value}
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node = Node{ID: 0, TermType: "bnode", IRI: "_:" + term.Value, Label: nil, X: 0, Y: 0}
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} else {
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key = termKey{termType: "uri", key: term.Value}
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node = Node{ID: 0, TermType: "uri", IRI: term.Value, Label: nil, X: 0, Y: 0}
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}
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if existing, ok := g.nodeIDByKey[key]; ok {
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return existing, true
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}
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if len(g.nodes) >= g.nodeLimit {
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return 0, false
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}
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nid := uint32(len(g.nodes))
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g.nodeIDByKey[key] = nid
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node.ID = nid
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g.nodes = append(g.nodes, node)
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return nid, true
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}
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func (g *graphAccumulator) addBindings(bindings []map[string]sparqlTerm) {
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for _, b := range bindings {
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sTerm := b["s"]
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oTerm := b["o"]
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pTerm := b["p"]
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sid, okS := g.getOrAddNode(sTerm)
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oid, okO := g.getOrAddNode(oTerm)
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if !okS || !okO {
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continue
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}
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predID, ok := g.preds.GetOrAdd(pTerm.Value)
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if !ok {
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continue
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}
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g.edges = append(g.edges, Edge{
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Source: sid,
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Target: oid,
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PredicateID: predID,
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})
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}
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}
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func min(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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