From a5d948d207e52d862f58ea118ee66035fd3d6b50 Mon Sep 17 00:00:00 2001
From: axothy <globaltouareg@gmail.com>
Date: Wed, 3 Jan 2024 17:19:10 +0500
Subject: [PATCH] Fixed MurmurHash

---
 .../ru/vk/itmo/chebotinalexandr/MurmurHash.java |  5 ++---
 .../chebotinalexandr/NotOnlyInMemoryDao.java    | 17 +++++++++++++++--
 src/test/java/ru/vk/itmo/BasicTest.java         |  4 ++++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/main/java/ru/vk/itmo/chebotinalexandr/MurmurHash.java b/src/main/java/ru/vk/itmo/chebotinalexandr/MurmurHash.java
index c3a6c4fb4..e758ab8e2 100644
--- a/src/main/java/ru/vk/itmo/chebotinalexandr/MurmurHash.java
+++ b/src/main/java/ru/vk/itmo/chebotinalexandr/MurmurHash.java
@@ -16,6 +16,7 @@
  */
 public final class MurmurHash {
     public static final int DEFAULT_SEED = 104729;
+    public static final VarHandle LITTLE_ENDIAN_LONG = MethodHandles.memorySegmentViewVarHandle(ValueLayout.JAVA_LONG_UNALIGNED);
 
     private MurmurHash() {
 
@@ -136,9 +137,7 @@ private static long getBlock(MemorySegment key, int offset, int index) {
         int i16 = index << 4; //blocks are 16 bytes
         int blockOffset = offset + i16;
 
-        ByteBuffer buffer = key.asByteBuffer().order(ByteOrder.nativeOrder());
-        buffer.position(blockOffset);
-        return buffer.getLong();
+        return (long) LITTLE_ENDIAN_LONG.get(key, blockOffset);
     }
 
     private static long rotl64(long v, int n) {
diff --git a/src/main/java/ru/vk/itmo/chebotinalexandr/NotOnlyInMemoryDao.java b/src/main/java/ru/vk/itmo/chebotinalexandr/NotOnlyInMemoryDao.java
index ba1c0d887..ce0def877 100644
--- a/src/main/java/ru/vk/itmo/chebotinalexandr/NotOnlyInMemoryDao.java
+++ b/src/main/java/ru/vk/itmo/chebotinalexandr/NotOnlyInMemoryDao.java
@@ -98,7 +98,13 @@ public Entry<MemorySegment> get(MemorySegment key) {
             return result.value() == null ? null : result;
         }
 
-        for (MemorySegment sstable : currState.sstables) {
+        return getFromDisk(key, currState);
+    }
+
+    private Entry<MemorySegment> getFromDisk(MemorySegment key, State state) {
+        Entry<MemorySegment> result;
+
+        for (MemorySegment sstable : state.sstables) {
             if (BloomFilter.sstableMayContain(key, sstable)) {
                 result = SSTableUtils.get(sstable, key);
 
@@ -124,7 +130,13 @@ public Entry<MemorySegment> getNoBloomFilter(MemorySegment key) {
             return result.value() == null ? null : result;
         }
 
-        for (MemorySegment sstable : currState.sstables) {
+        return getFromDiskNoBloomFilter(key, currState);
+    }
+
+    private Entry<MemorySegment> getFromDiskNoBloomFilter(MemorySegment key, State state) {
+        Entry<MemorySegment> result;
+
+        for (MemorySegment sstable : state.sstables) {
             result = SSTableUtils.get(sstable, key);
 
             if (result != null) {
@@ -135,6 +147,7 @@ public Entry<MemorySegment> getNoBloomFilter(MemorySegment key) {
         return null;
     }
 
+
     private PeekingIterator<Entry<MemorySegment>> range(
             Iterator<Entry<MemorySegment>> firstIterator,
             Iterator<Entry<MemorySegment>> secondIterator,
diff --git a/src/test/java/ru/vk/itmo/BasicTest.java b/src/test/java/ru/vk/itmo/BasicTest.java
index 11a882ffd..ca15edf45 100644
--- a/src/test/java/ru/vk/itmo/BasicTest.java
+++ b/src/test/java/ru/vk/itmo/BasicTest.java
@@ -1,11 +1,14 @@
 package ru.vk.itmo;
 
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Timeout;
 import org.opentest4j.AssertionFailedError;
+import ru.vk.itmo.test.DaoFactory;
 
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Random;
 
 /**
  * @author incubos
@@ -152,4 +155,5 @@ void testHugeData(Dao<String, Entry<String>> dao) throws Exception {
             assertSame(dao.get(keyAt(entry)), entryAt(entry));
         }
     }
+
 }