From ffe3f3473196f5490fd6a0e4340423aef3e5bd75 Mon Sep 17 00:00:00 2001
From: Ivan Hetman <Ihromant@users.noreply.github.com>
Date: Wed, 15 Mar 2023 12:09:49 +0200
Subject: [PATCH] classlib: add BitSet stream API (#674)

---
 .../org/teavm/classlib/java/util/TBitSet.java | 28 ++++++++++++++++++-
 .../teavm/classlib/java/util/BitSetTest.java  | 19 +++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java b/classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java
index 35ab92f0a..41202ae44 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/util/TBitSet.java
@@ -15,8 +15,11 @@
  */
 package org.teavm.classlib.java.util;
 
+import java.util.function.IntPredicate;
 import org.teavm.classlib.java.io.TSerializable;
 import org.teavm.classlib.java.lang.*;
+import org.teavm.classlib.java.util.stream.TIntStream;
+import org.teavm.classlib.java.util.stream.intimpl.TSimpleIntStreamImpl;
 import org.teavm.interop.Rename;
 
 public class TBitSet extends TObject implements TCloneable, TSerializable {
@@ -40,7 +43,7 @@ public class TBitSet extends TObject implements TCloneable, TSerializable {
     public static TBitSet valueOf(long[] longs) {
         int[] ints = new int[longs.length * 2];
         for (int i = 0; i < longs.length; ++i) {
-            ints[i * 2 + 1] = (int) longs[i];
+            ints[i * 2] = (int) longs[i];
             ints[i * 2 + 1] = (int) (longs[i] >>> TInteger.SIZE);
         }
         return new TBitSet(ints);
@@ -511,6 +514,29 @@ public class TBitSet extends TObject implements TCloneable, TSerializable {
         return sb.toString();
     }
 
+    public TIntStream stream() {
+        return new BitSetStream();
+    }
+
+    private class BitSetStream extends TSimpleIntStreamImpl {
+        private int current;
+
+        private BitSetStream() {
+            this.current = nextSetBit(0);
+        }
+
+        @Override
+        public boolean next(IntPredicate consumer) {
+            while (current >= 0) {
+                if (!consumer.test(current)) {
+                    return true;
+                }
+                current = nextSetBit(current + 1);
+            }
+            return false;
+        }
+    }
+
     @Rename("clone")
     public TObject clone0() {
         return new TBitSet(TArrays.copyOf(data, data.length));
diff --git a/tests/src/test/java/org/teavm/classlib/java/util/BitSetTest.java b/tests/src/test/java/org/teavm/classlib/java/util/BitSetTest.java
index 6962d3d2b..a2067a29a 100644
--- a/tests/src/test/java/org/teavm/classlib/java/util/BitSetTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/util/BitSetTest.java
@@ -47,6 +47,7 @@
  */
 package org.teavm.classlib.java.util;
 
+import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
@@ -98,6 +99,24 @@ public class BitSetTest {
         }
     }
 
+    @Test
+    public void constructFromLongs() {
+        BitSet bs = BitSet.valueOf(new long[] { 7, 2, 5, 1L << 36 });
+        assertTrue(bs.get(0) && bs.get(1) && bs.get(2) && bs.get(Long.SIZE + 1)
+                && bs.get(2 * Long.SIZE) && bs.get(2 * Long.SIZE + 2) && bs.get(3 * Long.SIZE + 36));
+        assertFalse(bs.get(3) || bs.get(Long.SIZE + 6) || bs.get(2 * Long.SIZE + 15) || bs.get(3 * Long.SIZE));
+    }
+
+    @Test
+    public void testStream() {
+        assertArrayEquals(new int[] { 0, 1, 2, Long.SIZE + 1, 2 * Long.SIZE, 2 * Long.SIZE + 2, 3 * Long.SIZE + 36 },
+                BitSet.valueOf(new long[] { 7, 2, 5, 1L << 36 }).stream().toArray());
+        BitSet bs = new BitSet();
+        assertEquals(0, bs.stream().count());
+        bs.set(1);
+        assertArrayEquals(new int[] { 1 }, bs.stream().toArray());
+    }
+
     @Test
     public void clonePerformed() {
         BitSet bs;