Initial commit of Hyperscan

src/nfa/limex_ring.h

@@ -0,0 +1,106 @@
+/*
+ * 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 Bounded Repeat implementation for the LimEx NFA.
+ */
+
+#ifndef LIMEX_RING_H
+#define LIMEX_RING_H
+
+#include "ue2common.h"
+#include "repeat.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+/** \brief Return values from \ref processTugTrigger, used to provide feedback
+ * about a bounded repeat to the caller.
+ *
+ * TRIGGER_FAIL does not get cached as we prefer to use TRIGGER_STALE which
+ * allows the exception to squash the cyclic state as well. */
+enum TriggerResult {
+    TRIGGER_FAIL,    /**< no valid matches, but history still valid */
+    TRIGGER_SUCCESS, /**< valid match found */
+    TRIGGER_STALE,   /**< no valid matches and history is invalid (stale) */
+    TRIGGER_SUCCESS_CACHE /**< valid match found; can cache as the repeat has no
+                             upper bound. */
+};
+
+/** \brief Handle a TUG trigger: given an \p offset, returns whether a repeat
+ * matches or not. */
+static really_inline
+enum TriggerResult processTugTrigger(const struct RepeatInfo *info,
+                                     const union RepeatControl *ctrl,
+                                     const char *state, u64a offset) {
+    DEBUG_PRINTF("tug trigger, %s history, repeat={%u,%u}, offset=%llu, "
+                 "ctrl=%p, state=%p\n",
+                 repeatTypeName(info->type), info->repeatMin, info->repeatMax,
+                 offset, ctrl, state);
+
+    assert(ISALIGNED(ctrl));
+
+    enum RepeatMatch rv = repeatHasMatch(info, ctrl, state, offset);
+    switch (rv) {
+    case REPEAT_NOMATCH:
+        return TRIGGER_FAIL;
+    case REPEAT_STALE:
+        return TRIGGER_STALE;
+    case REPEAT_MATCH:
+        if (info->repeatMax == REPEAT_INF) {
+            // {N,} repeats can be cached.
+            return TRIGGER_SUCCESS_CACHE;
+        } else {
+            return TRIGGER_SUCCESS;
+        }
+    }
+
+    assert(0); // unreachable
+    return TRIGGER_FAIL;
+}
+
+/** \brief Handle a POS trigger: stores a top in the repeat. */
+static really_inline
+void processPosTrigger(const struct RepeatInfo *info, union RepeatControl *ctrl,
+                       char *state, u64a offset, char is_alive) {
+    DEBUG_PRINTF("pos trigger, %s history, repeat={%u,%u}, offset=%llu, "
+                 "is_alive=%d\n", repeatTypeName(info->type),
+                 info->repeatMin, info->repeatMax, offset, is_alive);
+
+    assert(ISALIGNED(ctrl));
+
+    repeatStore(info, ctrl, state, offset, is_alive);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif