From 07ece06c99c9b15c5d2ea779239f856e066c97da Mon Sep 17 00:00:00 2001
From: amistry <amistry@chromium.org>
Date: Tue, 24 Nov 2015 01:05:54 -0800
Subject: Replace base::HashPair macros with a templated function.

Review URL: https://codereview.chromium.org/1445013002

Cr-Commit-Position: refs/heads/master@{#361299}
---
 base/containers/hash_tables.h | 57 ++++++-------------------------------------
 1 file changed, 8 insertions(+), 49 deletions(-)

(limited to 'base/containers')

diff --git a/base/containers/hash_tables.h b/base/containers/hash_tables.h
index 5ce9161..a1244f7 100644
--- a/base/containers/hash_tables.h
+++ b/base/containers/hash_tables.h
@@ -247,57 +247,16 @@ inline std::size_t HashInts64(uint64 value1, uint64 value2) {
   return high_bits;
 }
 
-#define DEFINE_32BIT_PAIR_HASH(Type1, Type2) \
-inline std::size_t HashPair(Type1 value1, Type2 value2) { \
-  return HashInts32(value1, value2); \
+template<typename T1, typename T2>
+inline std::size_t HashPair(T1 value1, T2 value2) {
+  // This condition is expected to be compile-time evaluated and optimised away
+  // in release builds.
+  if (sizeof(T1) > sizeof(uint32_t) || (sizeof(T2) > sizeof(uint32_t)))
+    return HashInts64(value1, value2);
+
+  return HashInts32(value1, value2);
 }
 
-DEFINE_32BIT_PAIR_HASH(int16, int16);
-DEFINE_32BIT_PAIR_HASH(int16, uint16);
-DEFINE_32BIT_PAIR_HASH(int16, int32);
-DEFINE_32BIT_PAIR_HASH(int16, uint32);
-DEFINE_32BIT_PAIR_HASH(uint16, int16);
-DEFINE_32BIT_PAIR_HASH(uint16, uint16);
-DEFINE_32BIT_PAIR_HASH(uint16, int32);
-DEFINE_32BIT_PAIR_HASH(uint16, uint32);
-DEFINE_32BIT_PAIR_HASH(int32, int16);
-DEFINE_32BIT_PAIR_HASH(int32, uint16);
-DEFINE_32BIT_PAIR_HASH(int32, int32);
-DEFINE_32BIT_PAIR_HASH(int32, uint32);
-DEFINE_32BIT_PAIR_HASH(uint32, int16);
-DEFINE_32BIT_PAIR_HASH(uint32, uint16);
-DEFINE_32BIT_PAIR_HASH(uint32, int32);
-DEFINE_32BIT_PAIR_HASH(uint32, uint32);
-
-#undef DEFINE_32BIT_PAIR_HASH
-
-#define DEFINE_64BIT_PAIR_HASH(Type1, Type2) \
-inline std::size_t HashPair(Type1 value1, Type2 value2) { \
-  return HashInts64(value1, value2); \
-}
-
-DEFINE_64BIT_PAIR_HASH(int16, int64);
-DEFINE_64BIT_PAIR_HASH(int16, uint64);
-DEFINE_64BIT_PAIR_HASH(uint16, int64);
-DEFINE_64BIT_PAIR_HASH(uint16, uint64);
-DEFINE_64BIT_PAIR_HASH(int32, int64);
-DEFINE_64BIT_PAIR_HASH(int32, uint64);
-DEFINE_64BIT_PAIR_HASH(uint32, int64);
-DEFINE_64BIT_PAIR_HASH(uint32, uint64);
-DEFINE_64BIT_PAIR_HASH(int64, int16);
-DEFINE_64BIT_PAIR_HASH(int64, uint16);
-DEFINE_64BIT_PAIR_HASH(int64, int32);
-DEFINE_64BIT_PAIR_HASH(int64, uint32);
-DEFINE_64BIT_PAIR_HASH(int64, int64);
-DEFINE_64BIT_PAIR_HASH(int64, uint64);
-DEFINE_64BIT_PAIR_HASH(uint64, int16);
-DEFINE_64BIT_PAIR_HASH(uint64, uint16);
-DEFINE_64BIT_PAIR_HASH(uint64, int32);
-DEFINE_64BIT_PAIR_HASH(uint64, uint32);
-DEFINE_64BIT_PAIR_HASH(uint64, int64);
-DEFINE_64BIT_PAIR_HASH(uint64, uint64);
-
-#undef DEFINE_64BIT_PAIR_HASH
 }  // namespace base
 
 namespace BASE_HASH_NAMESPACE {
-- 
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