Merge "Move BitUtils, RingBuffer test to coretests"

/*

 * Copyright (C) 2021 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 static com.android.internal.util.BitUtils.bytesToBEInt;

import static com.android.internal.util.BitUtils.bytesToLEInt;

import static com.android.internal.util.BitUtils.getUint16;

import static com.android.internal.util.BitUtils.getUint32;

import static com.android.internal.util.BitUtils.getUint8;

import static com.android.internal.util.BitUtils.packBits;

import static com.android.internal.util.BitUtils.uint16;

import static com.android.internal.util.BitUtils.uint32;

import static com.android.internal.util.BitUtils.uint8;

import static com.android.internal.util.BitUtils.unpackBits;

import static org.junit.Assert.assertEquals;

import static org.junit.Assert.assertTrue;

import androidx.test.ext.junit.runners.AndroidJUnit4;

import androidx.test.filters.SmallTest;

import org.junit.Test;

import org.junit.runner.RunWith;

import java.nio.ByteBuffer;

import java.util.Arrays;

import java.util.Random;

@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 testUnsignedShortComposition() {

        byte b0 = 0;

        byte b1 = 1;

        byte b2 = 2;

        byte b10 = 10;

        byte b16 = 16;

        byte b128 = -128;

        byte b224 = -32;

        byte b255 = -1;

        assertEquals(0x0000, uint16(b0, b0));

        assertEquals(0xffff, uint16(b255, b255));

        assertEquals(0x0a01, uint16(b10, b1));

        assertEquals(0x8002, uint16(b128, b2));

        assertEquals(0x01ff, uint16(b1, b255));

        assertEquals(0x80ff, uint16(b128, b255));

        assertEquals(0xe010, uint16(b224, b16));

    }

    @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));

    }

    @Test

    public void testBitsPacking() {

        BitPackingTestCase[] testCases = {

            new BitPackingTestCase(0, ints()),

            new BitPackingTestCase(1, ints(0)),

            new BitPackingTestCase(2, ints(1)),

            new BitPackingTestCase(3, ints(0, 1)),

            new BitPackingTestCase(4, ints(2)),

            new BitPackingTestCase(6, ints(1, 2)),

            new BitPackingTestCase(9, ints(0, 3)),

            new BitPackingTestCase(~Long.MAX_VALUE, ints(63)),

            new BitPackingTestCase(~Long.MAX_VALUE + 1, ints(0, 63)),

            new BitPackingTestCase(~Long.MAX_VALUE + 2, ints(1, 63)),

        };

        for (BitPackingTestCase tc : testCases) {

            int[] got = unpackBits(tc.packedBits);

            assertTrue(

                    "unpackBits("

                            + tc.packedBits

                            + "): expected "

                            + Arrays.toString(tc.bits)

                            + " but got "

                            + Arrays.toString(got),

                    Arrays.equals(tc.bits, got));

        }

        for (BitPackingTestCase tc : testCases) {

            long got = packBits(tc.bits);

            assertEquals(

                    "packBits("

                            + Arrays.toString(tc.bits)

                            + "): expected "

                            + tc.packedBits

                            + " but got "

                            + got,

                    tc.packedBits,

                    got);

        }

        long[] moreTestCases = {

            0, 1, -1, 23895, -908235, Long.MAX_VALUE, Long.MIN_VALUE, new Random().nextLong(),

        };

        for (long l : moreTestCases) {

            assertEquals(l, packBits(unpackBits(l)));

        }

    }

    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;

    }

    static int[] ints(int... array) {

        return array;

    }

    static class BitPackingTestCase {

        final int[] bits;

        final long packedBits;

        BitPackingTestCase(long packedBits, int[] bits) {

            this.bits = bits;

            this.packedBits = packedBits;

        }

    }

}

/*

 * Copyright (C) 2021 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 static org.junit.Assert.assertArrayEquals;

import static org.junit.Assert.assertNull;

import static org.junit.Assert.fail;

import androidx.test.ext.junit.runners.AndroidJUnit4;

import androidx.test.filters.SmallTest;

import org.junit.Test;

import org.junit.runner.RunWith;

@SmallTest

@RunWith(AndroidJUnit4.class)

public class RingBufferTest {

    @Test

    public void testEmptyRingBuffer() {

        RingBuffer<String> buffer = new RingBuffer<>(String.class, 100);

        assertArrayEquals(new String[0], buffer.toArray());

    }

    @Test

    public void testIncorrectConstructorArguments() {

        try {

            RingBuffer<String> buffer = new RingBuffer<>(String.class, -10);

            fail("Should not be able to create a negative capacity RingBuffer");

        } catch (IllegalArgumentException expected) {

        }

        try {

            RingBuffer<String> buffer = new RingBuffer<>(String.class, 0);

            fail("Should not be able to create a 0 capacity RingBuffer");

        } catch (IllegalArgumentException expected) {

        }

    }

    @Test

    public void testRingBufferWithNoWrapping() {

        RingBuffer<String> buffer = new RingBuffer<>(String.class, 100);

        buffer.append("a");

        buffer.append("b");

        buffer.append("c");

        buffer.append("d");

        buffer.append("e");

        String[] expected = {"a", "b", "c", "d", "e"};

        assertArrayEquals(expected, buffer.toArray());

    }

    @Test

    public void testRingBufferWithCapacity1() {

        RingBuffer<String> buffer = new RingBuffer<>(String.class, 1);

        buffer.append("a");

        assertArrayEquals(new String[]{"a"}, buffer.toArray());

        buffer.append("b");

        assertArrayEquals(new String[]{"b"}, buffer.toArray());

        buffer.append("c");

        assertArrayEquals(new String[]{"c"}, buffer.toArray());

        buffer.append("d");

        assertArrayEquals(new String[]{"d"}, buffer.toArray());

        buffer.append("e");

        assertArrayEquals(new String[]{"e"}, buffer.toArray());

    }

    @Test

    public void testRingBufferWithWrapping() {

        int capacity = 100;

        RingBuffer<String> buffer = new RingBuffer<>(String.class, capacity);

        buffer.append("a");

        buffer.append("b");

        buffer.append("c");

        buffer.append("d");

        buffer.append("e");

        String[] expected1 = {"a", "b", "c", "d", "e"};

        assertArrayEquals(expected1, buffer.toArray());

        String[] expected2 = new String[capacity];

        int firstIndex = 0;

        int lastIndex = capacity - 1;

        expected2[firstIndex] = "e";

        for (int i = 1; i < capacity; i++) {

            buffer.append("x");

            expected2[i] = "x";

        }

        assertArrayEquals(expected2, buffer.toArray());

        buffer.append("x");

        expected2[firstIndex] = "x";

        assertArrayEquals(expected2, buffer.toArray());

        for (int i = 0; i < 10; i++) {

            for (String s : expected2) {

                buffer.append(s);

            }

        }

        assertArrayEquals(expected2, buffer.toArray());

        buffer.append("a");

        expected2[lastIndex] = "a";

        assertArrayEquals(expected2, buffer.toArray());

    }

    @Test

    public void testGetNextSlot() {

        int capacity = 100;

        RingBuffer<DummyClass1> buffer = new RingBuffer<>(DummyClass1.class, capacity);

        final DummyClass1[] actual = new DummyClass1[capacity];

        final DummyClass1[] expected = new DummyClass1[capacity];

        for (int i = 0; i < capacity; ++i) {

            final DummyClass1 obj = buffer.getNextSlot();

            obj.x = capacity * i;

            actual[i] = obj;

            expected[i] = new DummyClass1();

            expected[i].x = capacity * i;

        }

        assertArrayEquals(expected, buffer.toArray());

        for (int i = 0; i < capacity; ++i) {

            if (actual[i] != buffer.getNextSlot()) {

                fail("getNextSlot() should re-use objects if available");

            }

        }

        RingBuffer<DummyClass2> buffer2 = new RingBuffer<>(DummyClass2.class, capacity);

        assertNull("getNextSlot() should return null if the object can't be initiated "

                + "(No nullary constructor)", buffer2.getNextSlot());

        RingBuffer<DummyClass3> buffer3 = new RingBuffer<>(DummyClass3.class, capacity);

        assertNull("getNextSlot() should return null if the object can't be initiated "

                + "(Inaccessible class)", buffer3.getNextSlot());

    }

    public static final class DummyClass1 {

        int x;

        public boolean equals(Object o) {

            if (o instanceof DummyClass1) {

                final DummyClass1 other = (DummyClass1) o;

                return other.x == this.x;

            }

            return false;

        }

    }

    public static final class DummyClass2 {

        public DummyClass2(int x) {}

    }

    private static final class DummyClass3 {}

}