Initial commit of Hyperscan

src/nfagraph/ng_split.cpp

@@ -0,0 +1,216 @@
+/*
+ * Copyright (c) 2015, Intel Corporation
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *  * Neither the name of Intel Corporation nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file
+ * \brief Functions for splitting NFAGraphs into LHS and RHS.
+ */
+#include "ng_split.h"
+
+#include "ng_holder.h"
+#include "ng_prune.h"
+#include "ng_util.h"
+#include "util/container.h"
+#include "util/graph.h"
+#include "util/graph_range.h"
+#include "util/ue2_containers.h"
+
+#include <map>
+#include <set>
+#include <vector>
+
+using namespace std;
+
+namespace ue2 {
+
+static
+void clearAccepts(NGHolder &g) {
+    for (auto v : inv_adjacent_vertices_range(g.accept, g)) {
+        g[v].reports.clear();
+    }
+
+    for (auto v : inv_adjacent_vertices_range(g.acceptEod, g)) {
+        g[v].reports.clear();
+    }
+
+    clear_in_edges(g.accept, g);
+    clear_in_edges(g.acceptEod, g);
+    add_edge(g.accept, g.acceptEod, g);
+}
+
+static
+void filterSplitMap(const NGHolder &g, ue2::unordered_map<NFAVertex, NFAVertex> *out_map) {
+    ue2::unordered_set<NFAVertex> verts;
+    insert(&verts, vertices(g));
+    ue2::unordered_map<NFAVertex, NFAVertex>::iterator it = out_map->begin();
+    while (it != out_map->end()) {
+        ue2::unordered_map<NFAVertex, NFAVertex>::iterator jt = it;
+        ++it;
+        if (!contains(verts, jt->second)) {
+            out_map->erase(jt);
+        }
+    }
+}
+
+static
+void splitLHS(const NGHolder &base, const vector<NFAVertex> &pivots,
+              const vector<NFAVertex> &rhs_pivots,
+              NGHolder *lhs, ue2::unordered_map<NFAVertex, NFAVertex> *lhs_map) {
+    assert(lhs && lhs_map);
+
+    cloneHolder(*lhs, base, lhs_map);
+
+    clearAccepts(*lhs);
+
+    for (auto pivot : pivots) {
+        DEBUG_PRINTF("pivot is %u lv %zu lm %zu\n", base[pivot].index,
+                     num_vertices(*lhs), lhs_map->size());
+        assert(contains(*lhs_map, pivot));
+
+        for (auto v : rhs_pivots) {
+            assert(contains(*lhs_map, v));
+            remove_edge((*lhs_map)[pivot], (*lhs_map)[v], *lhs);
+        }
+
+        (*lhs)[(*lhs_map)[pivot]].reports.insert(0);
+        add_edge((*lhs_map)[pivot], lhs->accept, *lhs);
+    }
+
+    pruneUseless(*lhs);
+    filterSplitMap(*lhs, lhs_map);
+
+    switch (base.kind) {
+    case NFA_PREFIX:
+    case NFA_OUTFIX:
+        lhs->kind = NFA_PREFIX;
+        break;
+    case NFA_INFIX:
+    case NFA_SUFFIX:
+        lhs->kind = NFA_INFIX;
+        break;
+    case NFA_REV_PREFIX:
+        assert(0);
+        break;
+    }
+}
+
+void splitLHS(const NGHolder &base, NFAVertex pivot,
+              NGHolder *lhs, ue2::unordered_map<NFAVertex, NFAVertex> *lhs_map) {
+    vector<NFAVertex> pivots(1, pivot);
+    vector<NFAVertex> rhs_pivots;
+    insert(&rhs_pivots, rhs_pivots.end(), adjacent_vertices(pivot, base));
+    splitLHS(base, pivots, rhs_pivots, lhs, lhs_map);
+}
+
+void splitRHS(const NGHolder &base, const vector<NFAVertex> &pivots,
+              NGHolder *rhs, ue2::unordered_map<NFAVertex, NFAVertex> *rhs_map) {
+    assert(rhs && rhs_map);
+
+    cloneHolder(*rhs, base, rhs_map);
+
+    clear_out_edges(rhs->start, *rhs);
+    clear_out_edges(rhs->startDs, *rhs);
+    add_edge(rhs->start, rhs->startDs, *rhs);
+    add_edge(rhs->startDs, rhs->startDs, *rhs);
+
+    for (auto pivot : pivots) {
+        assert(contains(*rhs_map, pivot));
+        add_edge(rhs->start, (*rhs_map)[pivot], *rhs);
+    }
+    pruneUseless(*rhs);
+    filterSplitMap(*rhs, rhs_map);
+
+    switch (base.kind) {
+    case NFA_PREFIX:
+    case NFA_INFIX:
+        rhs->kind = NFA_INFIX;
+        break;
+    case NFA_SUFFIX:
+    case NFA_OUTFIX:
+        rhs->kind = NFA_SUFFIX;
+        break;
+    case NFA_REV_PREFIX:
+        assert(0);
+        break;
+    }
+}
+
+/** \brief Fills \a succ with the common successors of the vertices in \a
+ * pivots. */
+static
+void findCommonSuccessors(const NGHolder &g, const vector<NFAVertex> &pivots,
+                          vector<NFAVertex> &succ) {
+    assert(!pivots.empty());
+
+    // Note: for determinism, we must sort our successor sets by vertex_index.
+    set<NFAVertex, VertexIndexOrdering<NGHolder> > adj(g), adj_temp(g);
+
+    insert(&adj, adjacent_vertices(pivots.at(0), g));
+
+    for (auto it = pivots.begin() + 1, ite = pivots.end(); it != ite; ++it) {
+        NFAVertex pivot = *it;
+        adj_temp.clear();
+        for (auto v : adjacent_vertices_range(pivot, g)) {
+            if (contains(adj, v)) {
+                adj_temp.insert(v);
+            }
+        }
+        adj.swap(adj_temp);
+    }
+
+    succ.insert(succ.end(), adj.begin(), adj.end());
+}
+
+void splitGraph(const NGHolder &base, const vector<NFAVertex> &pivots,
+                NGHolder *lhs, ue2::unordered_map<NFAVertex, NFAVertex> *lhs_map,
+                NGHolder *rhs, ue2::unordered_map<NFAVertex, NFAVertex> *rhs_map) {
+    DEBUG_PRINTF("splitting graph at %zu vertices\n", pivots.size());
+
+    assert(!has_parallel_edge(base));
+
+    /* RHS pivots are built from the common set of successors of pivots. */
+    vector<NFAVertex> rhs_pivots;
+    findCommonSuccessors(base, pivots, rhs_pivots);
+
+    /* generate lhs */
+    splitLHS(base, pivots, rhs_pivots, lhs, lhs_map);
+
+    /* generate the rhs */
+    splitRHS(base, rhs_pivots, rhs, rhs_map);
+
+    assert(!has_parallel_edge(*lhs));
+    assert(!has_parallel_edge(*rhs));
+}
+
+void splitGraph(const NGHolder &base, NFAVertex pivot,
+                NGHolder *lhs, ue2::unordered_map<NFAVertex, NFAVertex> *lhs_map,
+                NGHolder *rhs, ue2::unordered_map<NFAVertex, NFAVertex> *rhs_map) {
+    vector<NFAVertex> pivots(1, pivot);
+    splitGraph(base, pivots, lhs, lhs_map, rhs, rhs_map);
+}
+
+} // namespace ue2