1 files changed, 42 insertions, 0 deletions
diff --git a/decoder/node_state_hash.h b/decoder/node_state_hash.h
new file mode 100644
index 00000000..9fc01a09
--- /dev/null
+++ b/decoder/node_state_hash.h
@@ -0,0 +1,42 @@
+#ifndef _NODE_STATE_HASH_
+#define _NODE_STATE_HASH_
+
+#include <cassert>
+#include <cstring>
+#include "tdict.h"
+#include "murmur_hash3.h"
+#include "ffset.h"
+
+namespace cdec {
+
+  struct FirstPassNode {
+    FirstPassNode(int cat, int i, int j, int pi, int pj) : s(i), t(j), u(pi), v(pj) {
+      memset(lhs, 0, 120);
+      unsigned it = 0;
+      for (auto& c : TD::Convert(-cat)) { lhs[it++] = c; if (it == 120) break; }
+    }
+    char lhs[120];
+    short s;
+    short t;
+    short u;
+    short v;
+  };
+
+  inline uint64_t HashNode(int cat, int i, int j, int pi, int pj) {
+    FirstPassNode fpn(cat, i, j, pi, pj);
+    return MurmurHash3_64(&fpn, sizeof(FirstPassNode), 2654435769U);
+  }
+
+  inline uint64_t HashNode(uint64_t old_hash, const FFState& state) {
+    if (state.size() == 0) return old_hash;
+    uint8_t buf[1024];
+    std::memcpy(buf, &old_hash, sizeof(uint64_t));
+    assert(state.size() < (1024u - sizeof(uint64_t)));
+    std::memcpy(&buf[sizeof(uint64_t)], state.begin(), state.size());
+    return MurmurHash3_64(buf, sizeof(uint64_t) + state.size(), 2654435769U);
+  }
+
+}
+
+#endif
+