#3 Fixed a number of issue related to bit sets and blocks allocation in VanillaChronicleMap

src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java

@@ -133,7 +133,8 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
         this.removeReturnsNull = builder.removeReturnsNull();
 
         this.actualSegments = builder.actualSegments();
-        this.entriesPerSegment = builder.actualEntriesPerSegment();
+        // align by 8 because otherwise sizeOfBitSets() might address less blocks than specified
+        this.entriesPerSegment = align8(builder.actualEntriesPerSegment());
         this.metaDataBytes = builder.metaDataBytes();
         this.eventListener = builder.eventListener();
 
@@ -158,6 +159,10 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
         return (l + 63) & ~63;
     }
 
+    static int align8(int n) {
+        return (n + 7) & ~7;
+    }
+
     void initTransients() {
         keyReaderProvider = Provider.of((Class) originalKeyReader.getClass());
         keyInteropProvider = Provider.of((Class) originalKeyInterop.getClass());
@@ -555,8 +560,8 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
             long start = bytes.startAddr() + SEGMENT_HEADER;
             createHashLookups(start);
             start += align64(sizeOfMultiMap() + sizeOfMultiMapBitSet()) * multiMapsPerSegment();
-            final NativeBytes bsBytes = new NativeBytes(
-                    tmpBytes.objectSerializer(), start, start + sizeOfBitSets(), null);
+            final NativeBytes bsBytes = new NativeBytes(tmpBytes.objectSerializer(),
+                    start, start + ((entriesPerSegment + 7) / 8), null);
             freeList = new SingleThreadedDirectBitSet(bsBytes);
             start += numberOfBitSets() * sizeOfBitSets();
             entriesOffset = start - bytes.startAddr();
@@ -914,15 +919,23 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
                         );
                     }
                 }
+                updateNextPosToSearchFrom(ret, blocks);
+            } else {
+                // if bit at nextPosToSearchFrom is clear, it was skipped because
+                // more than 1 block was requested. Don't move nextPosToSearchFrom
+                // in this case. blocks == 1 clause is just a fast path.
+                if (blocks == 1 || freeList.isSet(nextPosToSearchFrom)) {
+                    updateNextPosToSearchFrom(ret, blocks);
+                }
             }
-            // if bit at nextPosToSearchFrom is clear, it was skipped because
-            // more than 1 block was requested. Don't move nextPosToSearchFrom
-            // in this case. blocks == 1 clause is just a fast path.
-            if (blocks == 1 || freeList.isSet(nextPosToSearchFrom))
-                nextPosToSearchFrom = ret + blocks;
             return ret;
         }
 
+        private void updateNextPosToSearchFrom(int allocated, int blocks) {
+            if ((nextPosToSearchFrom = allocated + blocks) >= freeList.size())
+                nextPosToSearchFrom = 0;
+        }
+
         private boolean realloc(int fromPos, int oldBlocks, int newBlocks) {
             if (freeList.allClear(fromPos + oldBlocks, fromPos + newBlocks)) {
                 freeList.set(fromPos + oldBlocks, fromPos + newBlocks);
@@ -1188,6 +1201,7 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
             try {
                 hashLookup.clear();
                 freeList.clear();
+                nextPosToSearchFrom = 0;
                 resetSize();
             } finally {
                 unlock();

src/test/java/net/openhft/chronicle/map/Issue3.java

@@ -0,0 +1,28 @@
+package net.openhft.chronicle.map;
+
+import net.openhft.chronicle.set.ChronicleSet;
+import net.openhft.chronicle.set.ChronicleSetBuilder;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.Random;
+import java.util.Set;
+
+public class Issue3 {
+
+    @Test
+    public void test() throws IOException {
+        Set<Long> set = ChronicleSetBuilder.of(Long.class)
+                .actualSegments(1)
+                .actualEntriesPerSegment(1000)
+                .create();
+
+        Random r = new Random();
+        for (int i = 0; i < 10; i++) {
+            for (int j = 0; j < 300; j++) {
+                set.add(r.nextLong());
+            }
+            set.clear();
+        }
+    }
+}