1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
use asexp::atom::Atom; use asexp::token::{Token, Tokenizer}; use asexp::Sexp; use petgraph::graph::NodeIndex; use petgraph::{Directed, Graph}; use std::collections::BTreeMap; pub fn parse_gml<NodeWeightFn, EdgeWeightFn, N, E>( s: &str, node_weight_fn: &NodeWeightFn, edge_weight_fn: &EdgeWeightFn, ) -> Result<Graph<N, E, Directed>, &'static str> where NodeWeightFn: Fn(Option<&Sexp>) -> Option<N>, EdgeWeightFn: Fn(Option<&Sexp>) -> Option<E>, { match parse_gml_to_sexp(s) { Ok(sexp) => sexp_to_graph(sexp, node_weight_fn, edge_weight_fn), Err(_) => Err("Invalid GML"), } } fn parse_gml_to_sexp(s: &str) -> Result<Sexp, ()> { let iter = Tokenizer::new(s, true).with_curly_around(); let iter = iter.map(|t| match t { Token::OpenBracket => Token::OpenCurly, Token::CloseBracket => Token::CloseCurly, a => a, }); Sexp::parse_iter(iter) } fn sexp_to_graph<NodeWeightFn, EdgeWeightFn, N, E>( sexp: Sexp, node_weight_fn: &NodeWeightFn, edge_weight_fn: &EdgeWeightFn, ) -> Result<Graph<N, E, Directed>, &'static str> where NodeWeightFn: Fn(Option<&Sexp>) -> Option<N>, EdgeWeightFn: Fn(Option<&Sexp>) -> Option<E>, { let mut map = sexp.into_map()?; if let Some(Sexp::Map(v)) = map.remove("graph") { let mut node_map: BTreeMap<u64, NodeIndex> = BTreeMap::new(); let mut graph = Graph::new(); let mut edges = Vec::new(); for (k, v) in v { match k.get_str() { Some("directed") => match v.get_uint() { Some(1) => {} _ => { return Err("only directed graph supported"); } }, Some("node") => { let node_info = v.into_map()?; if let Some(&Sexp::Atom(Atom::UInt(node_id))) = node_info.get("id") { match node_weight_fn(node_info.get("weight")) { Some(weight) => { let idx = graph.add_node(weight); if node_map.insert(node_id, idx).is_some() { return Err("duplicate node-id"); } } None => { return Err("invalid node weight"); } } } else { return Err("Invalid id"); } } Some("edge") => { let edge_info = v.into_map()?; let source = if let Some(&Sexp::Atom(Atom::UInt(source))) = edge_info.get("source") { source } else { return Err("Invalid source id"); }; let target = if let Some(&Sexp::Atom(Atom::UInt(target))) = edge_info.get("target") { target } else { return Err("Invalid target id"); }; match edge_weight_fn(edge_info.get("weight")) { Some(weight) => { edges.push((source, target, weight)); } None => { return Err("invalid edge weight"); } } } _ => { return Err("invalid item"); } } } for (source, target, weight) in edges { let source_idx = node_map[&source]; let target_idx = node_map[&target]; graph.add_edge(source_idx, target_idx, weight); } Ok(graph) } else { Err("no graph given or invalid") } } #[test] fn test_parse_gml() { let gml = " # comment graph [ directed 1 node [ id 1 \ weight 1.0 ] node [ id 2 ] edge \ [ source 1 target 2 weight 1.1000 ] \ edge [ source 2 target 1 ] ] "; let g = parse_gml( gml, &|s| -> Option<f64> { Some(s.and_then(Sexp::get_float).unwrap_or(0.0)) }, &|_| -> Option<()> { Some(()) }, ); assert!(g.is_ok()); let g = g.unwrap(); assert_eq!(true, g.is_directed()); assert_eq!( true, g.find_edge(NodeIndex::new(0), NodeIndex::new(1)).is_some() ); assert_eq!( true, g.find_edge(NodeIndex::new(1), NodeIndex::new(0)).is_some() ); assert_eq!(Some(&1.0), g.node_weight(NodeIndex::new(0))); assert_eq!(Some(&0.0), g.node_weight(NodeIndex::new(1))); }