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package org.openjdk.jmc.common.test;

import static org.openjdk.jmc.common.unit.BinaryPrefix.NOBI;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertSame;

import org.junit.Assert;
import org.junit.Test;

import org.openjdk.jmc.common.unit.BinaryPrefix;

public class BinaryPrefixTest extends MCTestCase {

	private void assertAlignmentLog2(int expectedLog2, long value) throws Exception {
		Assert.assertEquals(expectedLog2, BinaryPrefix.getAlignmentLog2(value));
	}

	private void assertAlignmentLog2(int expectedLog2, double value) throws Exception {
		Assert.assertEquals(expectedLog2, BinaryPrefix.getAlignmentLog2(value));
	}

	@Test
	public void testZero() {
		assertEquals(0, BinaryPrefix.getFloorLog1024(0));
		assertEquals(NOBI, BinaryPrefix.getFloorPrefix(0));
	}

	@Test
	public void testZeroDouble() {
		assertEquals(0, BinaryPrefix.getFloorLog1024(0.0));
		assertEquals(NOBI, BinaryPrefix.getFloorPrefix(0.0));
	}

	@Test
	public void testPositive() {
		int oldLog1024 = -1;
		BinaryPrefix oldPrefix = null;
		int i = 0;
		for (long val = 1; val != 0; val <<= 1) {
			int log1024 = BinaryPrefix.getFloorLog1024(val);
			BinaryPrefix prefix = BinaryPrefix.getFloorPrefix(val);

			if ((i++ % 10) == 0) {
				assertGreaterThan("For value " + val, oldLog1024, log1024);
				if (oldPrefix == null) {
					assertNotNull(prefix);
				} else {
					assertGreaterThan(oldPrefix, prefix);
				}
			} else {
				assertEquals("For value " + val, oldLog1024, log1024);
				assertSame(oldPrefix, prefix);
			}

			oldLog1024 = log1024;
			oldPrefix = prefix;
		}
	}

	@Test
	public void testPositiveDouble() {
		int oldLog1024 = -1;
		BinaryPrefix oldPrefix = null;
		int i = 0;
		for (int powOf2 = 0; powOf2 < 90; powOf2++) {
			double val = Math.scalb(1.0, powOf2);
			int log1024 = BinaryPrefix.getFloorLog1024(val);
			BinaryPrefix prefix = BinaryPrefix.getFloorPrefix(val);

			if ((i++ % 10) == 0) {
				assertGreaterThan("For value " + val, oldLog1024, log1024);
				if (oldPrefix == null) {
					assertNotNull(prefix);
				} else {
					assertGreaterThan(oldPrefix, prefix);
				}
			} else {
				assertEquals("For value " + val, oldLog1024, log1024);
				assertSame(oldPrefix, prefix);
			}

			oldLog1024 = log1024;
			oldPrefix = prefix;
		}
	}

	@Test
	public void testNegative() {
		int oldLog1024 = -1;
		BinaryPrefix oldPrefix = null;
		int i = 0;
		for (long val = -1; val != 0; val <<= 1) {
			int log1024 = BinaryPrefix.getFloorLog1024(val);
			BinaryPrefix prefix = BinaryPrefix.getFloorPrefix(val);

			if ((i++ % 10) == 0) {
				assertGreaterThan("For value " + val, oldLog1024, log1024);
				if (oldPrefix == null) {
					assertNotNull(prefix);
				} else {
					assertGreaterThan(oldPrefix, prefix);
				}
			} else {
				assertEquals("For value " + val, oldLog1024, log1024);
				assertSame(oldPrefix, prefix);
			}

			oldLog1024 = log1024;
			oldPrefix = prefix;
		}
	}

	@Test
	public void testNegativeDouble() {
		int oldLog1024 = -1;
		BinaryPrefix oldPrefix = null;
		int i = 0;
		for (int powOf2 = 0; powOf2 < 90; powOf2++) {
			double val = -Math.scalb(1.0, powOf2);
			int log1024 = BinaryPrefix.getFloorLog1024(val);
			BinaryPrefix prefix = BinaryPrefix.getFloorPrefix(val);

			if ((i++ % 10) == 0) {
				assertGreaterThan("For value " + val, oldLog1024, log1024);
				if (oldPrefix == null) {
					assertNotNull(prefix);
				} else {
					assertGreaterThan(oldPrefix, prefix);
				}
			} else {
				assertEquals("For value " + val, oldLog1024, log1024);
				assertSame(oldPrefix, prefix);
			}

			oldLog1024 = log1024;
			oldPrefix = prefix;
		}
	}

	@Test
	public void testBinaryLongAlignment() throws Exception {
		assertAlignmentLog2(0, 1);
		assertAlignmentLog2(0, 17);
		assertAlignmentLog2(0, 1027);
		assertAlignmentLog2(1, 2);
		assertAlignmentLog2(1, 42);
		assertAlignmentLog2(1, 1030);
		assertAlignmentLog2(2, 4);
		assertAlignmentLog2(3, 8);
		assertAlignmentLog2(4, 16);
		assertAlignmentLog2(10, 1024);
	}

	@Test
	public void testBinaryDoubleAlignment() throws Exception {
		assertAlignmentLog2(0, 1.0);
		assertAlignmentLog2(0, 17.0);
		assertAlignmentLog2(0, 1027.0);
		assertAlignmentLog2(1, 2.0);
		assertAlignmentLog2(1, 42.0);
		assertAlignmentLog2(1, 1030.0);
		assertAlignmentLog2(2, 4.0);
		assertAlignmentLog2(3, 8.0);
		assertAlignmentLog2(4, 16.0);
		assertAlignmentLog2(10, 1024.0);

		assertAlignmentLog2(-1, 0.5);
		assertAlignmentLog2(-1, 1.5);
		assertAlignmentLog2(-1, 17.5);
		assertAlignmentLog2(-1, 16777216.5);

		assertAlignmentLog2(-2, 0.25);
		assertAlignmentLog2(-2, 1.25);
		assertAlignmentLog2(-2, 17.25);
		assertAlignmentLog2(-2, 16777216.25);
	}
}