o Adding a more comprehensive test of the heap file. Still needs a lot more work.

5 files changed, 141 insertions, 12 deletions

diff --git a/src/main/java/io/trygvis/btree/HeapFile.java b/src/main/java/io/trygvis/btree/HeapFile.java
index 7a960c8..6bd0451 100644
--- a/src/main/java/io/trygvis/btree/HeapFile.java
+++ b/src/main/java/io/trygvis/btree/HeapFile.java
@@ -37,15 +37,18 @@ public class HeapFile implements Closeable {
         return HeapPage.heapPageFromBytes(page, buffer);
     }
 
-    public void writePage(HeapPage page) throws IOException {
+    public long writePage(HeapPage page) throws IOException {
         long position;
         if (page.pageNumber == -1) {
-            position = file.length();
+            position = channel.size();
         } else {
             position = page.pageNumber * PAGE_SIZE;
         }
+        page.bytes.rewind();
         channel.write(page.bytes, position);
         channel.force(true);
+
+        return position / PAGE_SIZE;
     }
 
     public long pageCount() throws IOException {
diff --git a/src/main/java/io/trygvis/btree/HeapPage.java b/src/main/java/io/trygvis/btree/HeapPage.java
index 499a244..a931260 100644
--- a/src/main/java/io/trygvis/btree/HeapPage.java
+++ b/src/main/java/io/trygvis/btree/HeapPage.java
@@ -22,7 +22,12 @@ public class HeapPage {
     }
 
     public static HeapPage heapPageFromBytes(int pageNumber, ByteBuffer bytes) {
-        int freePosition = bytes.getInt();
+        int freePosition = bytes.getInt(FREE_POSITION_INDEX);
+
+        if (freePosition > bytes.capacity() || freePosition < headerSize) {
+            throw new RuntimeException("Invalid free position: " + freePosition);
+        }
+
         return new HeapPage(pageNumber, bytes, freePosition);
     }
 
@@ -31,8 +36,6 @@ public class HeapPage {
     }
 
     public void append(byte[] item) {
-//        System.out.println("io.trygvis.btree.HeapPage.append");
-
         int bytesFree = bytesFree();
         int bytesRequested = item.length;
 
@@ -58,6 +61,8 @@ public class HeapPage {
         return new Iterable<ByteBuffer>() {
             @Override
             public Iterator<ByteBuffer> iterator() {
+                System.out.println("io.trygvis.btree.HeapPage.iterator");
+
                 return new Iterator<ByteBuffer>() {
                     private int position;
 
@@ -65,21 +70,27 @@ public class HeapPage {
 
                     {
                         position = bytes.capacity();
+                        System.out.println("position = " + position);
                         next = findNext();
                     }
 
                     private ByteBuffer findNext() {
+                        System.out.println("io.trygvis.btree.HeapPage.findNext");
                         if (position == headerSize) {
+                            System.out.println("at end");
                             return null;
                         }
 
                         int size = bytes.getInt(position - itemSize);
 
                         if (size == 0) {
+                            System.out.println("at end");
                             return null;
                         }
 
                         position -= itemSize + size;
+
+                        System.out.println("item: size: " + size + ", new position: " + position);
                         ByteBuffer copy = bytes.duplicate();
                         copy.position(position);
                         copy.limit(position + size);
diff --git a/src/test/java/io/trygvis/btree/HeapFileTest.java b/src/test/java/io/trygvis/btree/HeapFileTest.java
index a9105bb..558f192 100644
--- a/src/test/java/io/trygvis/btree/HeapFileTest.java
+++ b/src/test/java/io/trygvis/btree/HeapFileTest.java
@@ -4,6 +4,7 @@ import org.junit.Test;
 
 import java.io.File;
 
+import static io.trygvis.btree.TestUtils.deleteFile;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
@@ -12,16 +13,12 @@ public class HeapFileTest {
     @Test
     public void testBasic() throws Exception {
         int pageSize = 128;
-        File f = new File("target/heap");
-        if (f.exists()) {
-            assertTrue(f.delete());
-        }
-
-        HeapFile file = new HeapFile(pageSize, f);
+        HeapFile file = new HeapFile(pageSize, deleteFile(new File("target/heap")));
 
         assertEquals(0, file.pageCount());
         HeapPage page = file.blankPage();
-        file.writePage(page);
+        long pageNumber = file.writePage(page);
+        assertEquals(0, pageNumber);
         assertEquals(1, file.pageCount());
     }
 }
diff --git a/src/test/java/io/trygvis/btree/HeapTest.java b/src/test/java/io/trygvis/btree/HeapTest.java
new file mode 100644
index 0000000..1d724f4
--- /dev/null
+++ b/src/test/java/io/trygvis/btree/HeapTest.java
@@ -0,0 +1,103 @@
+package io.trygvis.btree;
+
+import org.junit.Test;
+
+import java.io.File;
+import java.nio.ByteBuffer;
+import java.util.Random;
+
+import static io.trygvis.btree.HeapTest.Person.randomPerson;
+import static io.trygvis.btree.TestUtils.deleteFile;
+import static org.junit.Assert.assertEquals;
+
+public class HeapTest {
+
+    @Test
+    public void testHeap() throws Exception {
+        File f = new File("target/heapTest");
+
+        HeapFile file = new HeapFile(128, deleteFile(f));
+
+        HeapPage page = file.blankPage();
+
+        int pageNo = 0;
+        for (int i = 0; i < 10; i++) {
+            Person p = randomPerson();
+
+            byte[] bytes = p.toBytes();
+
+            System.out.println("p = " + p + ", size = " + bytes.length);
+
+            if (page.bytesFree() < bytes.length) {
+                System.out.println("Flushing page");
+                long actualPageNo = file.writePage(page);
+                assertEquals(pageNo++, actualPageNo);
+                page = file.blankPage();
+            }
+
+            page.append(bytes);
+        }
+
+        long actualPageNo = file.writePage(page);
+        assertEquals(pageNo, actualPageNo);
+        file.close();
+
+        System.out.println("-------------------------------------------------------");
+        file = new HeapFile(128, f);
+
+        System.out.println("file.pageCount() = " + file.pageCount());
+
+        for (int i = 0; i < file.pageCount(); i++) {
+            System.out.println("page #" + i);
+            page = file.loadPage(i);
+
+            for (ByteBuffer buffer : page.bufferIterator()) {
+                Person p = Person.fromBytes(buffer);
+                System.out.println("p = " + p);
+            }
+        }
+    }
+
+    public static class Person {
+        private final String name;
+        private final int age;
+
+        public Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        public byte[] toBytes() {
+            byte[] s = name.getBytes();
+            ByteBuffer buffer = ByteBuffer.allocate(s.length + 8);
+            buffer.putInt(s.length);
+            buffer.put(s);
+            buffer.putInt(age);
+            return buffer.array();
+        }
+
+        public static Person fromBytes(ByteBuffer buffer) {
+            int stringSize = buffer.getInt();
+            byte[] s = new byte[stringSize];
+            buffer.get(s);
+            return new Person(new String(s), buffer.getInt());
+        }
+
+        @Override
+        public String toString() {
+            return "Person{" +
+                    "name='" + name + '\'' +
+                    ", age=" + age +
+                    '}';
+        }
+
+        private final static Random r = new Random(0);
+        private final static String[] names = new String[]{
+                "Lukas", "Emil", "Mathias", "Jonas", "Aleksander", "William", "Oskar", "Magnus", "Markus", "Oliver",
+                "Nora", "Emma", "Sofie", "Linnea", "Sara", "Emilie", "Ingrid", "Thea", "Leah", "Sofia"};
+
+        public static Person randomPerson() {
+            return new Person(names[r.nextInt(names.length)], r.nextInt(80) + 20);
+        }
+    }
+}
diff --git a/src/test/java/io/trygvis/btree/TestUtils.java b/src/test/java/io/trygvis/btree/TestUtils.java
new file mode 100644
index 0000000..92565e5
--- /dev/null
+++ b/src/test/java/io/trygvis/btree/TestUtils.java
@@ -0,0 +1,15 @@
+package io.trygvis.btree;
+
+import java.io.File;
+
+import static org.junit.Assert.assertTrue;
+
+public class TestUtils {
+    public static File deleteFile(File file) {
+        if (file.exists()) {
+            assertTrue(file.delete());
+        }
+
+        return file;
+    }
+}