From 2e12375a3e7b371ec186ff9798b8b006affbec83 Mon Sep 17 00:00:00 2001
From: Henning Baldersheim <balder@yahoo-inc.com>
Date: Tue, 17 Mar 2020 13:53:49 +0000
Subject: Order the bits so it is more suitable as a hash value.

---
 vespalib/src/vespa/vespalib/datastore/entryref.h   | 5 ++---
 vespalib/src/vespa/vespalib/datastore/entryref.hpp | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

(limited to 'vespalib')

diff --git a/vespalib/src/vespa/vespalib/datastore/entryref.h b/vespalib/src/vespa/vespalib/datastore/entryref.h
index c65e788637f..d49b1ab9071 100644
--- a/vespalib/src/vespa/vespalib/datastore/entryref.h
+++ b/vespalib/src/vespa/vespalib/datastore/entryref.h
@@ -32,9 +32,8 @@ public:
     EntryRefT() : EntryRef() {}
     EntryRefT(size_t offset_, uint32_t bufferId_);
     EntryRefT(const EntryRef & ref_) : EntryRef(ref_.ref()) {}
-    uint32_t hash() const { return offset() + (bufferId() << OffsetBits); }
-    size_t offset() const { return _ref >> BufferBits; }
-    uint32_t bufferId() const { return _ref & (numBuffers() - 1); }
+    size_t offset() const { return _ref & (offsetSize() - 1); }
+    uint32_t bufferId() const { return _ref >> OffsetBits; }
     static size_t offsetSize() { return 1ul << OffsetBits; }
     static uint32_t numBuffers() { return 1 << BufferBits; } 
     static size_t align(size_t val) { return val; }
diff --git a/vespalib/src/vespa/vespalib/datastore/entryref.hpp b/vespalib/src/vespa/vespalib/datastore/entryref.hpp
index 6e8b94f8989..b7aafb30fdd 100644
--- a/vespalib/src/vespa/vespalib/datastore/entryref.hpp
+++ b/vespalib/src/vespa/vespalib/datastore/entryref.hpp
@@ -9,7 +9,7 @@ namespace search::datastore {
 
 template <uint32_t OffsetBits, uint32_t BufferBits>
 EntryRefT<OffsetBits, BufferBits>::EntryRefT(size_t offset_, uint32_t bufferId_) :
-    EntryRef((offset_ << BufferBits) + bufferId_)
+    EntryRef((bufferId_ << OffsetBits) + offset_)
 {
     ASSERT_ONCE_OR_LOG(offset_ < offsetSize(), "EntryRefT.offset_overflow", 10000);
     ASSERT_ONCE_OR_LOG(bufferId_ < numBuffers(), "EntryRefT.bufferId_overflow", 10000);
-- 
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