Merge pull request #667 from LingMan/mathutils

Updates to MathUtils

h2/src/main/org/h2/engine/SysProperties.java

@@ -338,8 +338,15 @@ public class SysProperties {
      * The maximum number of objects in the cache.
      * This value must be a power of 2.
      */
-    public static final int OBJECT_CACHE_SIZE =
-            MathUtils.nextPowerOf2(Utils.getProperty("h2.objectCacheSize", 1024));
+    public static final int OBJECT_CACHE_SIZE;
+    static {
+        try {
+            OBJECT_CACHE_SIZE = MathUtils.nextPowerOf2(
+                    Utils.getProperty("h2.objectCacheSize", 1024));
+        } catch (IllegalArgumentException e) {
+            throw new IllegalStateException("Invalid h2.objectCacheSize", e);
+        }
+    }
 
     /**
      * System property <code>h2.oldStyleOuterJoin</code>

h2/src/main/org/h2/index/BaseIndex.java

@@ -21,7 +21,6 @@ import org.h2.table.Column;
 import org.h2.table.IndexColumn;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
-import org.h2.util.MathUtils;
 import org.h2.util.StatementBuilder;
 import org.h2.util.StringUtils;
 import org.h2.value.Value;
@@ -348,7 +347,7 @@ public abstract class BaseIndex extends SchemaObjectBase implements Index {
             if (isMultiVersion) {
                 int v1 = rowData.getVersion();
                 int v2 = compare.getVersion();
-                return MathUtils.compareInt(v2, v1);
+                return Integer.compare(v2, v1);
             }
             return 0;
         }

h2/src/main/org/h2/index/MultiVersionCursor.java

@@ -10,7 +10,6 @@ import org.h2.engine.SysProperties;
 import org.h2.message.DbException;
 import org.h2.result.Row;
 import org.h2.result.SearchRow;
-import org.h2.util.MathUtils;
 
 /**
  * The cursor implementation for the multi-version index.
@@ -143,7 +142,7 @@ public class MultiVersionCursor implements Cursor {
                     // version would be compared as well
                     long k1 = deltaRow.getKey();
                     long k2 = baseRow.getKey();
-                    compare = MathUtils.compareLong(k1, k2);
+                    compare = Long.compare(k1, k2);
                 }
                 if (compare == 0) {
                     if (isDeleted) {

h2/src/main/org/h2/server/web/ConnectionInfo.java

@@ -5,7 +5,6 @@
  */
 package org.h2.server.web;
 
-import org.h2.util.MathUtils;
 import org.h2.util.StringUtils;
 
 /**
@@ -61,7 +60,7 @@ public class ConnectionInfo implements Comparable<ConnectionInfo> {
 
     @Override
     public int compareTo(ConnectionInfo o) {
-        return -MathUtils.compareInt(lastAccess, o.lastAccess);
+        return -Integer.compare(lastAccess, o.lastAccess);
     }
 
 }

h2/src/main/org/h2/tools/ConvertTraceFile.java

@@ -16,7 +16,6 @@ import java.util.StringTokenizer;
 import org.h2.message.DbException;
 import org.h2.store.fs.FileUtils;
 import org.h2.util.IOUtils;
-import org.h2.util.MathUtils;
 import org.h2.util.New;
 import org.h2.util.StringUtils;
 import org.h2.util.Tool;
@@ -46,9 +45,9 @@ public class ConvertTraceFile extends Tool {
             if (other == this) {
                 return 0;
             }
-            int c = MathUtils.compareLong(other.time, time);
+            int c = Long.compare(other.time, time);
             if (c == 0) {
-                c = MathUtils.compareInt(other.executeCount, executeCount);
+                c = Integer.compare(other.executeCount, executeCount);
                 if (c == 0) {
                     c = sql.compareTo(other.sql);
                 }

h2/src/main/org/h2/util/CacheLRU.java

@@ -51,11 +51,17 @@ public class CacheLRU implements Cache {
         this.writer = writer;
         this.fifo = fifo;
         this.setMaxMemory(maxMemoryKb);
-        long tmpLen = MathUtils.nextPowerOf2(maxMemory / 64);
-        if (tmpLen > Integer.MAX_VALUE) {
-            throw new IllegalStateException("do not support this much cache memory: " + maxMemoryKb + "kb");
+        try {
+            // Since setMaxMemory() ensures that maxMemory is >=0,
+            // we don't have to worry about an underflow.
+            long tmpLen = maxMemory / 64;
+            if (tmpLen > Integer.MAX_VALUE) {
+                throw new IllegalArgumentException();
+            }
+            this.len = MathUtils.nextPowerOf2((int) tmpLen);
+        } catch (IllegalArgumentException e) {
+            throw new IllegalStateException("This much cache memory is not supported: " + maxMemoryKb + "kb", e);
         }
-        this.len = (int) tmpLen;
         this.mask = len - 1;
         clear();
     }

h2/src/main/org/h2/util/CacheObject.java

@@ -77,7 +77,7 @@ public abstract class CacheObject implements Comparable<CacheObject> {
 
     @Override
     public int compareTo(CacheObject other) {
-        return MathUtils.compareInt(getPos(), other.getPos());
+        return Integer.compare(getPos(), other.getPos());
     }
 
     public boolean isStream() {

h2/src/main/org/h2/util/MathUtils.java

@@ -204,7 +204,7 @@ public class MathUtils {
      * @param s the message to print
      * @param t the stack trace
      */
-    static void warn(String s, Throwable t) {
+    private static void warn(String s, Throwable t) {
         // not a fatal problem, but maybe reduced security
         System.out.println("Warning: " + s);
         if (t != null) {
@@ -213,33 +213,27 @@ public class MathUtils {
     }
 
     /**
-     * Get the value that is equal or higher than this value, and that is a
+     * Get the value that is equal to or higher than this value, and that is a
      * power of two.
      *
      * @param x the original value
      * @return the next power of two value
+     * @throws IllegalArgumentException if x < 0 or x > 0x40000000
      */
-    public static int nextPowerOf2(int x) {
-        long i = 1;
-        while (i < x && i < (Integer.MAX_VALUE / 2)) {
-            i += i;
+    public static int nextPowerOf2(int x) throws IllegalArgumentException {
+        if (x == 0) {
+            return 1;
+        } else if (x < 0 || x > 0x40000000 ) {
+            throw new IllegalArgumentException("Argument out of range"
+                    + " [0x0-0x40000000]. Argument was: " + x);
         }
-        return (int) i;
-    }
-
-    /**
-     * Get the value that is equal or higher than this value, and that is a
-     * power of two.
-     *
-     * @param x the original value
-     * @return the next power of two value
-     */
-    public static long nextPowerOf2(long x) {
-        long i = 1;
-        while (i < x && i < (Long.MAX_VALUE / 2)) {
-            i += i;
-        }
-        return i;
+        x--;
+        x |= x >> 1;
+        x |= x >> 2;
+        x |= x >> 4;
+        x |= x >> 8;
+        x |= x >> 16;
+        return ++x;
     }
 
     /**
@@ -260,30 +254,6 @@ public class MathUtils {
         }
     }
 
-    /**
-     * Compare two values. Returns -1 if the first value is smaller, 1 if
-     * bigger, and 0 if equal.
-     *
-     * @param a the first value
-     * @param b the second value
-     * @return the result
-     */
-    public static int compareInt(int a, int b) {
-        return a == b ? 0 : a < b ? -1 : 1;
-    }
-
-    /**
-     * Compare two values. Returns -1 if the first value is smaller, 1 if
-     * bigger, and 0 if equal.
-     *
-     * @param a the first value
-     * @param b the second value
-     * @return the result
-     */
-    public static int compareLong(long a, long b) {
-        return a == b ? 0 : a < b ? -1 : 1;
-    }
-
     /**
      * Get a cryptographically secure pseudo random long value.
      *

h2/src/main/org/h2/value/ValueByte.java

@@ -10,7 +10,6 @@ import java.sql.SQLException;
 
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
-import org.h2.util.MathUtils;
 
 /**
  * Implementation of the BYTE data type.
@@ -106,7 +105,7 @@ public class ValueByte extends Value {
     @Override
     protected int compareSecure(Value o, CompareMode mode) {
         ValueByte v = (ValueByte) o;
-        return MathUtils.compareInt(value, v.value);
+        return Integer.compare(value, v.value);
     }
 
     @Override

h2/src/main/org/h2/value/ValueDate.java

@@ -12,7 +12,6 @@ import java.sql.SQLException;
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
 import org.h2.util.DateTimeUtils;
-import org.h2.util.MathUtils;
 import org.h2.util.StringUtils;
 
 /**
@@ -121,7 +120,7 @@ public class ValueDate extends Value {
 
     @Override
     protected int compareSecure(Value o, CompareMode mode) {
-        return MathUtils.compareLong(dateValue, ((ValueDate) o).dateValue);
+        return Long.compare(dateValue, ((ValueDate) o).dateValue);
     }
 
     @Override

h2/src/main/org/h2/value/ValueEnum.java

@@ -8,7 +8,6 @@ package org.h2.value;
 import java.util.Locale;
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
-import org.h2.util.MathUtils;
 
 public class ValueEnum extends ValueEnumBase {
     private static enum Validation {
@@ -57,7 +56,7 @@ public class ValueEnum extends ValueEnumBase {
 
     @Override
     protected int compareSecure(final Value v, final CompareMode mode) {
-        return MathUtils.compareInt(getInt(), v.getInt());
+        return Integer.compare(getInt(), v.getInt());
     }
 
     /**

h2/src/main/org/h2/value/ValueEnumBase.java

@@ -7,7 +7,6 @@ package org.h2.value;
 
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
-import org.h2.util.MathUtils;
 
 /**
  * Base implementation of the ENUM data type.
@@ -35,7 +34,7 @@ public class ValueEnumBase extends Value {
 
     @Override
     protected int compareSecure(final Value v, final CompareMode mode) {
-        return MathUtils.compareInt(getInt(), v.getInt());
+        return Integer.compare(getInt(), v.getInt());
     }
 
     @Override

h2/src/main/org/h2/value/ValueInt.java

@@ -10,7 +10,6 @@ import java.sql.SQLException;
 
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
-import org.h2.util.MathUtils;
 
 /**
  * Implementation of the INT data type.
@@ -140,7 +139,7 @@ public class ValueInt extends Value {
     @Override
     protected int compareSecure(Value o, CompareMode mode) {
         ValueInt v = (ValueInt) o;
-        return MathUtils.compareInt(value, v.value);
+        return Integer.compare(value, v.value);
     }
 
     @Override

h2/src/main/org/h2/value/ValueLong.java

@@ -12,7 +12,6 @@ import java.sql.SQLException;
 
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
-import org.h2.util.MathUtils;
 
 /**
  * Implementation of the BIGINT data type.
@@ -171,7 +170,7 @@ public class ValueLong extends Value {
     @Override
     protected int compareSecure(Value o, CompareMode mode) {
         ValueLong v = (ValueLong) o;
-        return MathUtils.compareLong(value, v.value);
+        return Long.compare(value, v.value);
     }
 
     @Override

h2/src/main/org/h2/value/ValueShort.java

@@ -10,7 +10,6 @@ import java.sql.SQLException;
 
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
-import org.h2.util.MathUtils;
 
 /**
  * Implementation of the SMALLINT data type.
@@ -106,7 +105,7 @@ public class ValueShort extends Value {
     @Override
     protected int compareSecure(Value o, CompareMode mode) {
         ValueShort v = (ValueShort) o;
-        return MathUtils.compareInt(value, v.value);
+        return Integer.compare(value, v.value);
     }
 
     @Override

h2/src/main/org/h2/value/ValueTime.java

@@ -11,7 +11,6 @@ import java.sql.Time;
 import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
 import org.h2.util.DateTimeUtils;
-import org.h2.util.MathUtils;
 import org.h2.util.StringUtils;
 
 /**
@@ -129,7 +128,7 @@ public class ValueTime extends Value {
 
     @Override
     protected int compareSecure(Value o, CompareMode mode) {
-        return MathUtils.compareLong(nanos, ((ValueTime) o).nanos);
+        return Long.compare(nanos, ((ValueTime) o).nanos);
     }
 
     @Override

h2/src/main/org/h2/value/ValueTimestamp.java

@@ -16,7 +16,6 @@ import org.h2.api.ErrorCode;
 import org.h2.engine.Mode;
 import org.h2.message.DbException;
 import org.h2.util.DateTimeUtils;
-import org.h2.util.MathUtils;
 
 /**
  * Implementation of the TIMESTAMP data type.
@@ -310,11 +309,11 @@ public class ValueTimestamp extends Value {
     @Override
     protected int compareSecure(Value o, CompareMode mode) {
         ValueTimestamp t = (ValueTimestamp) o;
-        int c = MathUtils.compareLong(dateValue, t.dateValue);
+        int c = Long.compare(dateValue, t.dateValue);
         if (c != 0) {
             return c;
         }
-        return MathUtils.compareLong(timeNanos, t.timeNanos);
+        return Long.compare(timeNanos, t.timeNanos);
     }
 
     @Override

h2/src/main/org/h2/value/ValueTimestampTimeZone.java

@@ -14,7 +14,6 @@ import org.h2.api.ErrorCode;
 import org.h2.api.TimestampWithTimeZone;
 import org.h2.message.DbException;
 import org.h2.util.DateTimeUtils;
-import org.h2.util.MathUtils;
 import org.h2.util.StringUtils;
 
 /**
@@ -310,14 +309,14 @@ public class ValueTimestampTimeZone extends Value {
         b -= t.timeZoneOffsetMins;
 
         // compare date
-        int c = MathUtils.compareLong(a, b);
+        int c = Long.compare(a, b);
         if (c != 0) {
             return c;
         }
         // compare time
         long na = timeNanos - (ma * 1000L * 1000L * 1000L * 60L);
         long nb = t.timeNanos - (mb * 1000L * 1000L * 1000L * 60L);
-        return MathUtils.compareLong(na, nb);
+        return Long.compare(na, nb);
     }
 
     @Override

h2/src/main/org/h2/value/ValueUuid.java

@@ -159,7 +159,7 @@ public class ValueUuid extends Value {
         }
         ValueUuid v = (ValueUuid) o;
         if (high == v.high) {
-            return MathUtils.compareLong(low, v.low);
+            return Long.compare(low, v.low);
         }
         return high > v.high ? 1 : -1;
     }

h2/src/test/org/h2/test/unit/TestMathUtils.java

@@ -5,10 +5,7 @@
  */
 package org.h2.test.unit;
 
-import java.math.BigInteger;
-import java.util.Random;
 import org.h2.test.TestBase;
-import org.h2.test.utils.AssertThrows;
 import org.h2.util.MathUtils;
 
 /**
@@ -28,8 +25,7 @@ public class TestMathUtils extends TestBase {
     @Override
     public void test() {
         testRandom();
-        testReverse();
-        testFactorial();
+        testNextPowerOf2Int();
     }
 
     private void testRandom() {
@@ -53,78 +49,17 @@ public class TestMathUtils extends TestBase {
         assertTrue(data.length > 10);
     }
 
-    private void testReverse() {
-        assertEquals(Integer.reverse(0), Integer.reverse(0));
-        assertEquals(Integer.reverse(Integer.MAX_VALUE),
-                Integer.reverse(Integer.MAX_VALUE));
-        assertEquals(Integer.reverse(Integer.MIN_VALUE),
-                Integer.reverse(Integer.MIN_VALUE));
-        assertEquals(Long.reverse(0), Long.reverse(0L));
-        assertEquals(Long.reverse(Long.MAX_VALUE), Long.reverse(Long.MAX_VALUE));
-        assertEquals(Long.reverse(Long.MIN_VALUE), Long.reverse(Long.MIN_VALUE));
-        for (int i = Integer.MIN_VALUE; i < 0; i += 1019) {
-            int x = Integer.reverse(i);
-            assertEquals(Integer.reverse(i), x);
-        }
-        for (int i = 0; i > 0; i += 1019) {
-            int x = Integer.reverse(i);
-            assertEquals(Integer.reverse(i), x);
-        }
-        for (long i = Long.MIN_VALUE; i < 0; i += 1018764321251L) {
-            long x = Long.reverse(i);
-            assertEquals(Long.reverse(i), x);
-        }
-        for (long i = 0; i > 0; i += 1018764321251L) {
-            long x = Long.reverse(i);
-            assertEquals(Long.reverse(i), x);
-        }
-        Random random = new Random(10);
-        for (int i = 0; i < 1000000; i++) {
-            long x = random.nextLong();
-            long r = Long.reverse(x);
-            assertEquals(Long.reverse(x), r);
-            int y = random.nextInt();
-            int s = Integer.reverse(y);
-            assertEquals(Integer.reverse(y), s);
-        }
-    }
+    private void testNextPowerOf2Int() {
+        // the largest power of two that fits into an integer
+        final int LARGEST_POW2 = 0x40000000;
+        int[] testValues = { 0, 1, 2, 3, 4, 12, 17, 500, 1023,
+                LARGEST_POW2-500, LARGEST_POW2 };
+        int[] resultValues = { 1, 1, 2, 4, 4, 16, 32, 512, 1024,
+                LARGEST_POW2, LARGEST_POW2 };
 
-    private void testFactorial() {
-        new AssertThrows(IllegalArgumentException.class) { @Override
-        public void test() {
-            factorial(-1);
-        }};
-        assertEquals("1", factorial(0).toString());
-        assertEquals("1", factorial(1).toString());
-        assertEquals("2", factorial(2).toString());
-        assertEquals("6", factorial(3).toString());
-        assertEquals("3628800", factorial(10).toString());
-        assertEquals("2432902008176640000", factorial(20).toString());
-    }
-
-    /**
-     * Calculate the factorial (n!) of a number.
-     * This implementation uses a naive multiplication loop, and
-     * is very slow for large n.
-     * For n = 1000, it takes about 10 ms.
-     * For n = 8000, it takes about 800 ms.
-     *
-     * @param n the number
-     * @return the factorial of n
-     */
-    public static BigInteger factorial(int n) {
-        if (n < 0) {
-            throw new IllegalArgumentException(n + "<0");
-        } else if (n < 2) {
-            return BigInteger.ONE;
-        }
-        BigInteger x = new BigInteger("" + n);
-        BigInteger result = x;
-        for (int i = n - 1; i >= 2; i--) {
-            x = x.subtract(BigInteger.ONE);
-            result = result.multiply(x);
+        for (int i = 0; i < testValues.length; i++) {
+            assertEquals(resultValues[i], MathUtils.nextPowerOf2(testValues[i]));
         }
-        return result;
     }
 
 }