Started optimizing tree-lookup code using mmap

Author: oschwald

src/main/java/com/maxmind/maxminddb/Decoder.java

@@ -351,8 +351,6 @@ private long[] sizeFromCtrlByte(int ctrlByte, long offset)
     }
 
     private byte[] getByteArray(int length) {
-        byte[] bytes = new byte[length];
-        this.mmap.get(bytes);
-        return bytes;
+        return Util.getByteArray(this.mmap, length);
     }
 }

src/main/java/com/maxmind/maxminddb/Reader.java

@@ -58,7 +58,8 @@ public Reader(File database) throws MaxMindDbException, IOException {
 
         this.metadata = new Metadata(metadataDecoder.decode(start).getNode());
 
-        this.decoder = new Decoder(this.mmap, this.metadata.searchTreeSize + DATA_SECTION_SEPARATOR_SIZE);
+        this.decoder = new Decoder(this.mmap, this.metadata.searchTreeSize
+                + DATA_SECTION_SEPARATOR_SIZE);
 
         if (this.DEBUG) {
             Log.debug(this.metadata.toString());
@@ -74,7 +75,7 @@ public JsonNode get(InetAddress address) throws MaxMindDbException,
             return null;
         }
 
-        this.fc.position(pointer);
+        this.mmap.position((int) pointer);
         return this.resolveDataPointer(pointer);
     }
 
@@ -142,41 +143,33 @@ long record = nodes[bit];
 
     private long[] readNode(long nodeNumber) throws IOException,
             MaxMindDbException {
-        ByteBuffer buffer = ByteBuffer
-                .wrap(new byte[this.metadata.nodeByteSize]);
-        this.fc.position(nodeNumber * this.metadata.nodeByteSize);
+        this.mmap.position((int) nodeNumber * this.metadata.nodeByteSize);
 
-        this.fc.read(buffer);
+        byte[] buffer = Util
+                .getByteArray(this.mmap, this.metadata.nodeByteSize);
 
         if (this.DEBUG) {
             Log.debug("Node bytes", buffer);
         }
         return this.splitNodeIntoRecords(buffer);
     }
 
-    private long[] splitNodeIntoRecords(ByteBuffer bytes)
-            throws MaxMindDbException {
+    private long[] splitNodeIntoRecords(byte[] bytes) throws MaxMindDbException {
         long[] nodes = new long[2];
         switch (this.metadata.recordSize) {
             case 24:
-                nodes[0] = Util.decodeLong(Arrays.copyOfRange(bytes.array(), 0,
-                        3));
-                nodes[1] = Util.decodeLong(Arrays.copyOfRange(bytes.array(), 3,
-                        6));
+                nodes[0] = Util.decodeLong(Arrays.copyOfRange(bytes, 0, 3));
+                nodes[1] = Util.decodeLong(Arrays.copyOfRange(bytes, 3, 6));
                 return nodes;
             case 28:
-                nodes[0] = Util.decodeLong(Arrays.copyOfRange(bytes.array(), 0,
-                        3));
-                nodes[1] = Util.decodeLong(Arrays.copyOfRange(bytes.array(), 4,
-                        7));
-                nodes[0] = ((0xF0 & bytes.get(3)) << 20) | nodes[0];
-                nodes[1] = ((0x0F & bytes.get(3)) << 24) | nodes[1];
+                nodes[0] = Util.decodeLong(Arrays.copyOfRange(bytes, 0, 3));
+                nodes[1] = Util.decodeLong(Arrays.copyOfRange(bytes, 4, 7));
+                nodes[0] = ((0xF0 & bytes[3]) << 20) | nodes[0];
+                nodes[1] = ((0x0F & bytes[3]) << 24) | nodes[1];
                 return nodes;
             case 32:
-                nodes[0] = Util.decodeLong(Arrays.copyOfRange(bytes.array(), 0,
-                        4));
-                nodes[1] = Util.decodeLong(Arrays.copyOfRange(bytes.array(), 4,
-                        8));
+                nodes[0] = Util.decodeLong(Arrays.copyOfRange(bytes, 0, 4));
+                nodes[1] = Util.decodeLong(Arrays.copyOfRange(bytes, 4, 8));
                 return nodes;
             default:
                 throw new MaxMindDbException("Unknown record size: "

src/main/java/com/maxmind/maxminddb/Util.java

@@ -1,5 +1,7 @@
 package com.maxmind.maxminddb;
 
+import java.nio.ByteBuffer;
+
 class Util {
 
     public Util() {
@@ -22,4 +24,10 @@ static long decodeLong(byte[] bytes) {
         return i;
     }
 
+    static byte[] getByteArray(ByteBuffer buffer, int length) {
+        byte[] bytes = new byte[length];
+        buffer.get(bytes);
+        return bytes;
+    }
+
 }