keep hashes arrays sorted for faster checking

core/src/main/java/com/muwire/core/search/SearchIndexImpl.java

@@ -1,5 +1,6 @@
 package com.muwire.core.search;
 
+import com.muwire.core.util.DataUtil;
 import net.metanotionz.io.Serializer;
 import net.metanotionz.io.block.BlockFile;
 import net.metanotionz.util.skiplist.SkipList;
@@ -32,17 +33,8 @@ public class SearchIndexImpl {
                 keywords.put(keyword, existingHashes);
                 hashes.put(hash, new String[] {string});
             } else {
-                boolean found = false;
-                for (int existingHash : existingHashes) {
-                    if (existingHash == hash) {
-                        found = true;
-                        break;
-                    }
-                }
-                if (!found) {
-                    int [] newHashes = new int[existingHashes.length + 1];
-                    System.arraycopy(existingHashes, 0, newHashes, 0, existingHashes.length);
-                    newHashes[newHashes.length - 1] = hash;
+                int [] newHashes = DataUtil.insertIntoSortedArray(existingHashes, hash);
+                if (newHashes != existingHashes) {
                     keywords.put(keyword, newHashes);
                 }
 

core/src/main/java/com/muwire/core/util/DataUtil.java

@@ -5,13 +5,7 @@ import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Properties;
-import java.util.Set;
-import java.util.UUID;
+import java.util.*;
 import java.util.stream.Collectors;
 
 import com.muwire.core.Constants;
@@ -237,4 +231,24 @@ public class DataUtil {
         }
         return name.substring(lastDot + 1);
     }
+
+    /**
+     * Inserts an integer into an array if it's not already present
+     * @param array of sorted unique integers
+     * @param value to insert
+     * @return the same instance or a new instance with the element included
+     */
+    public static int[] insertIntoSortedArray(int [] array, int value) {
+        int pos = Arrays.binarySearch(array, value);
+        if (pos >= 0)
+            return array;
+        pos = - pos - 1;
+        int [] rv = new int[array.length + 1];
+        if (pos > 0)
+            System.arraycopy(array, 0, rv, 0, pos);
+        rv[pos] = value;
+        if (pos < rv.length - 1)
+            System.arraycopy(array, pos, rv, pos + 1, rv.length - pos - 1);
+        return rv;
+    }
 }

core/src/test/groovy/com/muwire/core/util/DataUtilTest.groovy

@@ -64,4 +64,40 @@ class DataUtilTest {
         } catch (IllegalArgumentException expected) {}
         
     }
+    
+    @Test
+    void testSortedArrayAfter() {
+        int [] array = new int[]{1}
+        int [] rv = DataUtil.insertIntoSortedArray(array, 2)
+        assert rv.length == 2
+        assert rv[0] == 1
+        assert rv[1] == 2
+    }
+    
+    @Test
+    void testSortedArrayBefore() {
+        int [] array = new int[]{1}
+        int [] rv = DataUtil.insertIntoSortedArray(array, 0)
+        assert rv.length == 2
+        assert rv[0] == 0
+        assert rv[1] == 1
+    }
+    
+    @Test
+    void testSortedArrayExisting() {
+        int [] array = new int[]{1}
+        int [] rv = DataUtil.insertIntoSortedArray(array, 1)
+        assert System.identityHashCode(array) == System.identityHashCode(rv)
+        assert array == rv
+    }
+    
+    @Test
+    void testSortedArrayMiddle() {
+        int [] array = new int[] {0, 2}
+        int [] rv = DataUtil.insertIntoSortedArray(array, 1)
+        assert rv.length == 3
+        assert rv[0] == 0
+        assert rv[1] == 1
+        assert rv[2] == 2
+    }
 }