Mark constexpr values needed within non-implicitly-capturing lambdas as static

[folly.git] / folly / Fingerprint.h

diff --git a/folly/Fingerprint.h b/folly/Fingerprint.h
index f1980ae215aa2b35afe248ad0e60b762fcad7b66..74302093b5a58e42bc0d99e37d11426376289566 100644 (file)
--- a/folly/Fingerprint.h
+++ b/folly/Fingerprint.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,12 +51,37 @@
 namespace folly {
 
 namespace detail {
+
 template <int BITS>
 struct FingerprintTable {
-  static const uint64_t poly[1 + (BITS-1)/64];
-  static const uint64_t table[8][256][1 + (BITS-1)/64];
+  static const uint64_t poly[1 + (BITS - 1) / 64];
+  static const uint64_t table[8][256][1 + (BITS - 1) / 64];
 };
-}  // namespace detail
+
+template <int BITS>
+const uint64_t FingerprintTable<BITS>::poly[1 + (BITS - 1) / 64] = {};
+template <int BITS>
+const uint64_t FingerprintTable<BITS>::table[8][256][1 + (BITS - 1) / 64] = {};
+
+#ifndef _MSC_VER
+// MSVC 2015 can't handle these extern specialization declarations,
+// but they aren't needed for things to work right, so we just don't
+// declare them in the header for MSVC.
+
+#define FOLLY_DECLARE_FINGERPRINT_TABLES(BITS)                      \
+  template <>                                                       \
+  const uint64_t FingerprintTable<BITS>::poly[1 + (BITS - 1) / 64]; \
+  template <>                                                       \
+  const uint64_t FingerprintTable<BITS>::table[8][256][1 + (BITS - 1) / 64]
+
+FOLLY_DECLARE_FINGERPRINT_TABLES(64);
+FOLLY_DECLARE_FINGERPRINT_TABLES(96);
+FOLLY_DECLARE_FINGERPRINT_TABLES(128);
+
+#undef FOLLY_DECLARE_FINGERPRINT_TABLES
+#endif
+
+} // namespace detail
 
 /**
  * Compute the Rabin fingerprint.