From 330ae0ac78c4dc454e1ca5673df290a8bea39a53 Mon Sep 17 00:00:00 2001
From: Hugo Benichi <hugobenichi@google.com>
Date: Thu, 12 Jan 2017 15:31:05 +0900
Subject: [PATCH] Move byte logics from ApfFilter into BitsUtil

This patch extracts into BitUtils byte manipulation helper methods
and unsigned type manipulation helper methods from ApfFilter into
an independent and reusable structure.

Test: $ runtest frameworks-net
Change-Id: I0f33af10457a63dbde5983f14353a79b8cd877d9
---
 .../android/internal/util/BitUtilsTest.java   | 107 ++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 tests/net/java/com/android/internal/util/BitUtilsTest.java

diff --git a/tests/net/java/com/android/internal/util/BitUtilsTest.java b/tests/net/java/com/android/internal/util/BitUtilsTest.java
new file mode 100644
index 0000000000..0ad8a21f77
--- /dev/null
+++ b/tests/net/java/com/android/internal/util/BitUtilsTest.java
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.util;
+
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+import java.nio.ByteBuffer;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.assertEquals;
+import static com.android.internal.util.BitUtils.*;
+
+@SmallTest
+@RunWith(AndroidJUnit4.class)
+public class BitUtilsTest {
+
+    @Test
+    public void testUnsignedByteWideningConversions() {
+        byte b0 = 0;
+        byte b1 = 1;
+        byte bm1 = -1;
+        assertEquals(0, uint8(b0));
+        assertEquals(1, uint8(b1));
+        assertEquals(127, uint8(Byte.MAX_VALUE));
+        assertEquals(128, uint8(Byte.MIN_VALUE));
+        assertEquals(255, uint8(bm1));
+        assertEquals(255, uint8((byte)255));
+    }
+
+    @Test
+    public void testUnsignedShortWideningConversions() {
+        short s0 = 0;
+        short s1 = 1;
+        short sm1 = -1;
+        assertEquals(0, uint16(s0));
+        assertEquals(1, uint16(s1));
+        assertEquals(32767, uint16(Short.MAX_VALUE));
+        assertEquals(32768, uint16(Short.MIN_VALUE));
+        assertEquals(65535, uint16(sm1));
+        assertEquals(65535, uint16((short)65535));
+    }
+
+    @Test
+    public void testUnsignedIntWideningConversions() {
+        assertEquals(0, uint32(0));
+        assertEquals(1, uint32(1));
+        assertEquals(2147483647L, uint32(Integer.MAX_VALUE));
+        assertEquals(2147483648L, uint32(Integer.MIN_VALUE));
+        assertEquals(4294967295L, uint32(-1));
+        assertEquals(4294967295L, uint32((int)4294967295L));
+    }
+
+    @Test
+    public void testBytesToInt() {
+        assertEquals(0x00000000, bytesToBEInt(bytes(0, 0, 0, 0)));
+        assertEquals(0xffffffff, bytesToBEInt(bytes(255, 255, 255, 255)));
+        assertEquals(0x0a000001, bytesToBEInt(bytes(10, 0, 0, 1)));
+        assertEquals(0x0a000002, bytesToBEInt(bytes(10, 0, 0, 2)));
+        assertEquals(0x0a001fff, bytesToBEInt(bytes(10, 0, 31, 255)));
+        assertEquals(0xe0000001, bytesToBEInt(bytes(224, 0, 0, 1)));
+
+        assertEquals(0x00000000, bytesToLEInt(bytes(0, 0, 0, 0)));
+        assertEquals(0x01020304, bytesToLEInt(bytes(4, 3, 2, 1)));
+        assertEquals(0xffff0000, bytesToLEInt(bytes(0, 0, 255, 255)));
+    }
+
+    @Test
+    public void testUnsignedGetters() {
+      ByteBuffer b = ByteBuffer.allocate(4);
+      b.putInt(0xffff);
+
+      assertEquals(0x0, getUint8(b, 0));
+      assertEquals(0x0, getUint8(b, 1));
+      assertEquals(0xff, getUint8(b, 2));
+      assertEquals(0xff, getUint8(b, 3));
+
+      assertEquals(0x0, getUint16(b, 0));
+      assertEquals(0xffff, getUint16(b, 2));
+
+      b.rewind();
+      b.putInt(0xffffffff);
+      assertEquals(0xffffffffL, getUint32(b, 0));
+    }
+
+    static byte[] bytes(int b1, int b2, int b3, int b4) {
+        return new byte[] {b(b1), b(b2), b(b3), b(b4)};
+    }
+
+    static byte b(int i) {
+        return (byte) i;
+    }
+}