Initial commit of Hyperscan

src/rose/rose_build_lookaround.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 Rose compile-time analysis for lookaround masks.
+ */
+#ifndef ROSE_ROSE_BUILD_LOOKAROUND_H
+#define ROSE_ROSE_BUILD_LOOKAROUND_H
+
+#include "rose_graph.h"
+
+#include <vector>
+
+namespace ue2 {
+
+class CharReach;
+class RoseBuildImpl;
+
+/** \brief Lookaround entry prototype, describing the reachability at a given
+ * distance from the end of a role match. */
+struct LookEntry {
+    LookEntry(s8 offset_in, const CharReach &reach_in)
+        : offset(offset_in), reach(reach_in) {}
+    s8 offset; //!< offset from role match location.
+    CharReach reach; //!< reachability at given offset.
+
+    bool operator==(const LookEntry &other) const {
+        return offset == other.offset && reach == other.reach;
+    }
+};
+
+static inline
+size_t hash_value(const LookEntry &l) {
+    size_t val = 0;
+    boost::hash_combine(val, l.offset);
+    boost::hash_combine(val, l.reach);
+    return val;
+}
+
+void findLookaroundMasks(const RoseBuildImpl &tbi, const RoseVertex v,
+                         std::vector<LookEntry> &lookaround);
+
+/**
+ * \brief If possible, render the prefix of the given vertex as a lookaround.
+ *
+ * Given a prefix, returns true (and fills the lookaround vector) if
+ * it can be satisfied with a lookaround alone.
+ */
+bool makeLeftfixLookaround(const RoseBuildImpl &build, const RoseVertex v,
+                           std::vector<LookEntry> &lookaround);
+
+void mergeLookaround(std::vector<LookEntry> &lookaround,
+                     const std::vector<LookEntry> &more_lookaround);
+
+} // namespace ue2
+
+#endif // ROSE_ROSE_BUILD_LOOKAROUND_H