1 files changed, 38 insertions, 0 deletions
diff --git a/third_party/wasm2c/src/hash-util.cc b/third_party/wasm2c/src/hash-util.cc
new file mode 100644
index 0000000000..efb8427028
--- /dev/null
+++ b/third_party/wasm2c/src/hash-util.cc
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+/*
+ * Copyright 2017 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "src/hash-util.h"
+
+#include "config.h"
+
+namespace wabt {
+
+// Hash combiner from:
+// http://stackoverflow.com/questions/4948780/magic-number-in-boosthash-combine
+
+hash_code HashCombine(hash_code seed, hash_code y) {
+#if SIZEOF_SIZE_T == 4
+  constexpr hash_code magic = 0x9e3779b9;
+#elif SIZEOF_SIZE_T == 8
+  constexpr hash_code magic = 0x9e3779b97f4a7c16;
+#else
+#error "weird sizeof size_t"
+#endif
+  seed ^= y + magic + (seed << 6) + (seed >> 2);
+  return seed;
+}
+
+}  // namespace wabt