Initial commit of Hyperscan

src/nfagraph/ng_region.h

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+/*
+ * 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 Region analysis and utility functions.
+ */
+
+#ifndef NG_REGION_H
+#define NG_REGION_H
+
+#include "ng_holder.h"
+#include "util/container.h"
+#include "util/graph_range.h"
+#include "util/ue2_containers.h"
+
+#include <vector>
+
+namespace ue2 {
+
+/** \brief Assign a region ID to every vertex in the graph. */
+ue2::unordered_map<NFAVertex, u32> assignRegions(const NGHolder &g);
+
+/** \brief True if vertices \p a and \p b are in the same region. */
+template <class Graph>
+bool inSameRegion(const Graph &g, NFAVertex a, NFAVertex b,
+                  const ue2::unordered_map<NFAVertex, u32> &region_map) {
+    assert(contains(region_map, a) && contains(region_map, b));
+
+    return region_map.at(a) == region_map.at(b) &&
+           is_special(a, g) == is_special(b, g);
+}
+
+/** \brief True if vertex \p b is in a later region than vertex \p a. */
+template <class Graph>
+bool inLaterRegion(const Graph &g, NFAVertex a, NFAVertex b,
+                   const ue2::unordered_map<NFAVertex, u32> &region_map) {
+    assert(contains(region_map, a) && contains(region_map, b));
+
+    u32 aa = g[a].index;
+    u32 bb = g[b].index;
+
+    if (bb == NODE_START || bb == NODE_START_DOTSTAR) {
+        return false;
+    }
+
+    if (aa == NODE_START || aa == NODE_START_DOTSTAR) {
+        return true;
+    }
+
+    if (bb == NODE_ACCEPT || bb == NODE_ACCEPT_EOD) {
+        return true;
+    }
+    if (aa == NODE_ACCEPT || aa == NODE_ACCEPT_EOD) {
+        return false;
+    }
+
+    return region_map.at(a) < region_map.at(b);
+}
+
+/** \brief True if vertex \p b is in an earlier region than vertex \p a. */
+template <class Graph>
+bool inEarlierRegion(const Graph &g, NFAVertex a, NFAVertex b,
+                     const ue2::unordered_map<NFAVertex, u32> &region_map) {
+    assert(contains(region_map, a) && contains(region_map, b));
+
+    u32 aa = g[a].index;
+    u32 bb = g[b].index;
+
+    if (bb == NODE_START || bb == NODE_START_DOTSTAR) {
+        return true;
+    }
+
+    if (aa == NODE_START || aa == NODE_START_DOTSTAR) {
+        return false;
+    }
+
+    if (bb == NODE_ACCEPT || bb == NODE_ACCEPT_EOD) {
+        return false;
+    }
+    if (aa == NODE_ACCEPT || aa == NODE_ACCEPT_EOD) {
+        return true;
+    }
+
+    return region_map.at(b) < region_map.at(a);
+}
+
+/** \brief True if vertex \p v is an entry vertex for its region. */
+template <class Graph>
+bool isRegionEntry(const Graph &g, NFAVertex v,
+                   const ue2::unordered_map<NFAVertex, u32> &region_map) {
+    // Note that some graph types do not have inv_adjacent_vertices, so we must
+    // use in_edges here.
+    for (const auto &e : in_edges_range(v, g)) {
+        if (!inSameRegion(g, v, source(e, g), region_map)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+/** \brief True if vertex \p v is an exit vertex for its region. */
+template <class Graph>
+bool isRegionExit(const Graph &g, NFAVertex v,
+                  const ue2::unordered_map<NFAVertex, u32> &region_map) {
+    for (auto w : adjacent_vertices_range(v, g)) {
+        if (!inSameRegion(g, v, w, region_map)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+/** \brief True if vertex \p v is in a region all on its own. */
+template <class Graph>
+bool isSingletonRegion(const Graph &g, NFAVertex v,
+                       const ue2::unordered_map<NFAVertex, u32> &region_map) {
+    for (const auto &e : in_edges_range(v, g)) {
+        auto u = source(e, g);
+        if (u != v && inSameRegion(g, v, u, region_map)) {
+            return false;
+        }
+
+        for (auto w : ue2::adjacent_vertices_range(u, g)) {
+            if (w != v && inSameRegion(g, v, w, region_map)) {
+                return false;
+            }
+        }
+    }
+
+    for (auto w : adjacent_vertices_range(v, g)) {
+        if (w != v && inSameRegion(g, v, w, region_map)) {
+            return false;
+        }
+
+        for (const auto &e : in_edges_range(w, g)) {
+            auto u = source(e, g);
+            if (u != v && inSameRegion(g, v, u, region_map)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    return true;
+}
+
+/**
+ * \brief True if the region containing vertex \p v is optional. The vertex \p v
+ * should be a region leader.
+ */
+template <class Graph>
+bool isOptionalRegion(const Graph &g, NFAVertex v,
+                      const ue2::unordered_map<NFAVertex, u32> &region_map) {
+    assert(isRegionEntry(g, v, region_map));
+
+    DEBUG_PRINTF("check if r%u is optional (inspecting v%u)\n",
+                  region_map.at(v), g[v].index);
+
+    // Region zero is never optional.
+    assert(contains(region_map, v));
+    if (region_map.at(v) == 0) {
+        return false;
+    }
+
+    // Optional if v has a predecessor in an earlier region that has a
+    // successor in a later one.
+
+    for (const auto &e : in_edges_range(v, g)) {
+        auto u = source(e, g);
+        if (inSameRegion(g, v, u, region_map)) {
+            continue;
+        }
+        DEBUG_PRINTF("  searching from u=%u\n", g[u].index);
+
+        assert(inEarlierRegion(g, v, u, region_map));
+
+        for (auto w : adjacent_vertices_range(u, g)) {
+            DEBUG_PRINTF("    searching to w=%u\n", g[w].index);
+            if (inLaterRegion(g, v, w, region_map)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    return false;
+}
+
+} // namespace ue2
+
+#endif