minor change on skiplist

tomfran · Oct 3, 2023 · c7fb7cc · c7fb7cc
1 parent 826d331
commit c7fb7cc
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Showing 5 changed files with 21 additions and 41 deletions.
diff --git a/src/main/java/com/tomfran/lsm/io/BaseInputStream.java b/src/main/java/com/tomfran/lsm/io/BaseInputStream.java
@@ -82,15 +82,6 @@ public ByteArrayPair readBytePair() {
         }
     }
 
-    public byte[] readByteArray() {
-        try {
-            int len = readVByteInt();
-            return fis.readNBytes(len);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
     public long skip(int n) {
         try {
             return fis.skip(n);
@@ -107,14 +98,6 @@ public void seek(long offset) {
         }
     }
 
-    public boolean hasNext() {
-        try {
-            return fis.available() > 0;
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
     public void close() {
         try {
             fis.close();

diff --git a/src/main/java/com/tomfran/lsm/memtable/Memtable.java b/src/main/java/com/tomfran/lsm/memtable/Memtable.java
@@ -21,7 +21,7 @@ public void add(ByteArrayPair item) {
         list.add(item);
     }
 
-    public ByteArrayPair get(byte[] key) {
+    public byte[] get(byte[] key) {
         return list.get(key);
     }
 

diff --git a/src/main/java/com/tomfran/lsm/memtable/SkipList.java b/src/main/java/com/tomfran/lsm/memtable/SkipList.java
@@ -52,13 +52,13 @@ public SkipList(int numElements) {
     public void add(ByteArrayPair item) {
         Node current = sentinel;
         for (int i = levels - 1; i >= 0; i--) {
-            while (current.next[i] != null && current.next[i].value.compareTo(item) < 0)
+            while (current.next[i] != null && current.next[i].val.compareTo(item) < 0)
                 current = current.next[i];
             buffer[i] = current;
         }
 
-        if (current.next[0] != null && current.next[0].value.compareTo(item) == 0) {
-            current.next[0].value = item;
+        if (current.next[0] != null && current.next[0].val.compareTo(item) == 0) {
+            current.next[0].val = item;
             return;
         }
 
@@ -83,15 +83,15 @@ private int randomLevel() {
      * @param key The key of the item to retrieve.
      * @return The item if found, null otherwise.
      */
-    public ByteArrayPair get(byte[] key) {
+    public byte[] get(byte[] key) {
         Node current = sentinel;
         for (int i = levels - 1; i >= 0; i--) {
-            while (current.next[i] != null && compare(current.next[i].value.key(), key) < 0)
+            while (current.next[i] != null && compare(current.next[i].val.key(), key) < 0)
                 current = current.next[i];
         }
 
-        if (current.next[0] != null && compare(current.next[0].value.key(), key) == 0)
-            return current.next[0].value;
+        if (current.next[0] != null && compare(current.next[0].val.key(), key) == 0)
+            return current.next[0].val.value();
 
         return null;
     }
@@ -104,12 +104,12 @@ public ByteArrayPair get(byte[] key) {
     public void remove(byte[] key) {
         Node current = sentinel;
         for (int i = levels - 1; i >= 0; i--) {
-            while (current.next[i] != null && compare(current.next[i].value.key(), key) < 0)
+            while (current.next[i] != null && compare(current.next[i].val.key(), key) < 0)
                 current = current.next[i];
             buffer[i] = current;
         }
 
-        if (current.next[0] != null && compare(current.next[0].value.key(), key) == 0) {
+        if (current.next[0] != null && compare(current.next[0].val.key(), key) == 0) {
             boolean last = current.next[0].next[0] == null;
             for (int i = 0; i < levels; i++) {
                 if (buffer[i].next[i] != current.next[0])
@@ -146,7 +146,7 @@ public String toString() {
             sb.append(String.format("Level %2d: ", i));
             Node current = sentinel;
             while (current.next[i] != null) {
-                sb.append(current.next[i].value).append(" -> ");
+                sb.append(current.next[i].val).append(" -> ");
                 current = current.next[i];
             }
             sb.append("END\n");
@@ -155,11 +155,11 @@ public String toString() {
     }
 
     private static final class Node {
-        ByteArrayPair value;
+        ByteArrayPair val;
         Node[] next;
 
-        Node(ByteArrayPair value, int numLevels) {
-            this.value = value;
+        Node(ByteArrayPair val, int numLevels) {
+            this.val = val;
             this.next = new Node[numLevels];
         }
     }
@@ -173,7 +173,7 @@ public boolean hasNext() {
 
         @Override
         public ByteArrayPair next() {
-            return node.next[0].value;
+            return node.next[0].val;
         }
     }
 

diff --git a/src/main/java/com/tomfran/lsm/tree/LSMTree.java b/src/main/java/com/tomfran/lsm/tree/LSMTree.java
@@ -37,8 +37,8 @@ private void checkMemtableSize() {
         }
     }
 
-    public ByteArrayPair get(byte[] key) {
-        ByteArrayPair result;
+    public byte[] get(byte[] key) {
+        byte[] result;
 
         if ((result = mutableMemtable.get(key)) != null)
             return result;
@@ -47,10 +47,9 @@ public ByteArrayPair get(byte[] key) {
             if ((result = memtable.get(key)) != null)
                 return result;
 
-        byte[] tmp;
         for (SSTable table : tables)
-            if ((tmp = table.get(key)) != null)
-                return new ByteArrayPair(key, tmp);
+            if ((result = table.get(key)) != null)
+                return result;
 
         return null;
     }

diff --git a/src/test/java/com/tomfran/lsm/memtable/SkipListTest.java b/src/test/java/com/tomfran/lsm/memtable/SkipListTest.java
@@ -36,8 +36,7 @@ public void shouldFind() {
         for (ByteArrayPair item : items) {
             var found = l.get(item.key());
             assert found != null;
-            assert compare(found.key(), item.key()) == 0;
-            assert compare(found.value(), item.value()) == 0;
+            assert compare(found, item.value()) == 0;
         }
     }
 
@@ -56,8 +55,7 @@ public void shouldRemove() {
                 assert found == null;
             } else {
                 assert found != null;
-                assert compare(found.key(), item.key()) == 0;
-                assert compare(found.value(), item.value()) == 0;
+                assert compare(found, item.value()) == 0;
             }
         }
     }