diff options
| -rw-r--r-- | core/java/com/android/internal/util/BitUtils.java | 6 | ||||
| -rw-r--r-- | tests/net/java/com/android/internal/util/BitUtilsTest.java | 87 |
2 files changed, 79 insertions, 14 deletions
diff --git a/core/java/com/android/internal/util/BitUtils.java b/core/java/com/android/internal/util/BitUtils.java index 61581458f98a..27d2cc240db3 100644 --- a/core/java/com/android/internal/util/BitUtils.java +++ b/core/java/com/android/internal/util/BitUtils.java @@ -68,9 +68,9 @@ public final class BitUtils { int[] result = new int[size]; int index = 0; int bitPos = 0; - while (val > 0) { + while (val != 0) { if ((val & 1) == 1) result[index++] = bitPos; - val = val >> 1; + val = val >>> 1; bitPos++; } return result; @@ -79,7 +79,7 @@ public final class BitUtils { public static long packBits(int[] bits) { long packed = 0; for (int b : bits) { - packed |= (1 << b); + packed |= (1L << b); } return packed; } diff --git a/tests/net/java/com/android/internal/util/BitUtilsTest.java b/tests/net/java/com/android/internal/util/BitUtilsTest.java index 01fb0df2d47e..d2fbdce9771a 100644 --- a/tests/net/java/com/android/internal/util/BitUtilsTest.java +++ b/tests/net/java/com/android/internal/util/BitUtilsTest.java @@ -21,11 +21,14 @@ 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.filters.SmallTest; import androidx.test.runner.AndroidJUnit4; @@ -34,6 +37,8 @@ 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) @@ -110,20 +115,66 @@ public class BitUtilsTest { @Test public void testUnsignedGetters() { - ByteBuffer b = ByteBuffer.allocate(4); - b.putInt(0xffff); + 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, 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)); + assertEquals(0x0, getUint16(b, 0)); + assertEquals(0xffff, getUint16(b, 2)); - b.rewind(); - b.putInt(0xffffffff); - assertEquals(0xffffffffL, getUint32(b, 0)); + 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) { @@ -133,4 +184,18 @@ public class BitUtilsTest { 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; + } + } } |