Initial commit of Hyperscan

src/nfagraph/ng_fixed_width.cpp

@@ -0,0 +1,142 @@
+/*
+ * 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 Rose mask construction from NGHolder.
+ */
+#include "ng_fixed_width.h"
+
+#include "grey.h"
+#include "ng_holder.h"
+#include "ng_util.h"
+#include "rose/rose_build.h"
+#include "util/container.h"
+#include "ue2common.h"
+
+#include <algorithm>
+#include <iterator>
+#include <set>
+
+using namespace std;
+
+namespace ue2 {
+
+static
+bool findMask(const NGHolder &g, vector<CharReach> *mask, bool *anchored,
+              ue2::flat_set<ReportID> *reports) {
+    DEBUG_PRINTF("looking for a mask pattern\n");
+    set<NFAVertex> s_succ;
+    insert(&s_succ, adjacent_vertices(g.start, g));
+
+    set<NFAVertex> sds_succ;
+    insert(&sds_succ, adjacent_vertices(g.startDs, g));
+
+    *anchored = sds_succ.size() == 1; /* sds itself */
+    bool floating = is_subset_of(s_succ, sds_succ);
+
+    DEBUG_PRINTF("sds %zu s %zu%s%s\n", sds_succ.size(), s_succ.size(),
+                 *anchored ? " anchored" : "", floating ? " floating" : "");
+    if (!*anchored && !floating) {
+        DEBUG_PRINTF("semi-anchored\n");
+        return false;
+    }
+
+    set<NFAVertex> &succs = *anchored ? s_succ : sds_succ;
+    succs.erase(g.startDs);
+    if (succs.size() != 1) {
+        DEBUG_PRINTF("branchy root\n");
+        return false;
+    }
+
+    NFAVertex u = *anchored ? g.start : g.startDs;
+    NFAVertex v = *succs.begin();
+
+    while (true) {
+        DEBUG_PRINTF("validating vertex %u\n", g[v].index);
+
+        assert(v != g.acceptEod);
+
+        // If we've reached an accept, we MAY have found a valid Rose pattern
+        if (v == g.accept) {
+            DEBUG_PRINTF("accept\n");
+            insert(reports, g[u].reports);
+            return true;
+        }
+
+        mask->push_back(g[v].char_reach);
+
+        if (out_degree(v, g) != 1) {
+            DEBUG_PRINTF("out_degree != 1\n");
+            return false; /* not a chain */
+        }
+
+        u = v;
+        v = *adjacent_vertices(v, g).first;
+
+        if (in_degree(v, g) != 1) {
+            DEBUG_PRINTF("blargh\n"); /* picks up cases where there is no path
+                                        * to case accept (large cycles),
+                                        * ensures term */
+            return false;
+        }
+    }
+}
+
+bool handleFixedWidth(RoseBuild &rose, const NGHolder &g, const Grey &grey) {
+    if (!grey.roseMasks) {
+        return false;
+    }
+
+    if (in_degree(g.acceptEod,g) != 1) {
+        DEBUG_PRINTF("EOD anchoring not supported\n");
+        return false;
+    }
+
+    ue2::flat_set<ReportID> reports;
+    bool anchored = false;
+    vector<CharReach> mask;
+
+    if (!findMask(g, &mask, &anchored, &reports)) {
+        return false;
+    }
+
+    DEBUG_PRINTF("%smasky masky\n", anchored ? "anchored " : "");
+
+    assert(!mask.empty());
+    assert(!reports.empty());
+
+    if (rose.add(anchored, mask, reports)) {
+        DEBUG_PRINTF("added as rose mask\n");
+        return true;
+    } else {
+        DEBUG_PRINTF("failed to add masky\n");
+        return false;
+    }
+}
+
+} // namespace ue2