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-rw-r--r--libjava/classpath/java/lang/Long.java153
1 files changed, 152 insertions, 1 deletions
diff --git a/libjava/classpath/java/lang/Long.java b/libjava/classpath/java/lang/Long.java
index 703eab8a0f3..74e2a52df7c 100644
--- a/libjava/classpath/java/lang/Long.java
+++ b/libjava/classpath/java/lang/Long.java
@@ -50,7 +50,7 @@ package java.lang;
* @author Warren Levy
* @author Eric Blake (ebb9@email.byu.edu)
* @since 1.0
- * @status updated to 1.4
+ * @status updated to 1.5
*/
public final class Long extends Number implements Comparable
{
@@ -79,6 +79,12 @@ public final class Long extends Number implements Comparable
public static final Class TYPE = VMClassLoader.getPrimitiveClass ('J');
/**
+ * The number of bits needed to represent a <code>long</code>.
+ * @since 1.5
+ */
+ public static final int SIZE = 64;
+
+ /**
* The immutable value of this Long.
*
* @serial the wrapped long
@@ -282,6 +288,21 @@ public final class Long extends Number implements Comparable
}
/**
+ * Returns a <code>Long</code> object wrapping the value.
+ *
+ * @param val the value to wrap
+ * @return the <code>Long</code>
+ *
+ * @since 1.5
+ */
+ public static synchronized Long valueOf(long val)
+ {
+ // We aren't required to cache here. We could, though perhaps we
+ // ought to consider that as an empirical question.
+ return new Long(val);
+ }
+
+ /**
* Convert the specified <code>String</code> into a <code>Long</code>.
* The <code>String</code> may represent decimal, hexadecimal, or
* octal numbers.
@@ -512,6 +533,136 @@ public final class Long extends Number implements Comparable
}
/**
+ * Return the number of bits set in x.
+ * @param x value to examine
+ * @since 1.5
+ */
+ public static int bitCount(long x)
+ {
+ // Successively collapse alternating bit groups into a sum.
+ x = ((x >> 1) & 0x5555555555555555L) + (x & 0x5555555555555555L);
+ x = ((x >> 2) & 0x3333333333333333L) + (x & 0x3333333333333333L);
+ int v = (int) ((x >>> 32) + x);
+ v = ((v >> 4) & 0x0f0f0f0f) + (v & 0x0f0f0f0f);
+ v = ((v >> 8) & 0x00ff00ff) + (v & 0x00ff00ff);
+ return ((v >> 16) & 0x0000ffff) + (v & 0x0000ffff);
+ }
+
+ /**
+ * Rotate x to the left by distance bits.
+ * @param x the value to rotate
+ * @param distance the number of bits by which to rotate
+ * @since 1.5
+ */
+ public static long rotateLeft(long x, int distance)
+ {
+ // This trick works because the shift operators implicitly mask
+ // the shift count.
+ return (x << distance) | (x >>> - distance);
+ }
+
+ /**
+ * Rotate x to the right by distance bits.
+ * @param x the value to rotate
+ * @param distance the number of bits by which to rotate
+ * @since 1.5
+ */
+ public static long rotateRight(long x, int distance)
+ {
+ // This trick works because the shift operators implicitly mask
+ // the shift count.
+ return (x << - distance) | (x >>> distance);
+ }
+
+ /**
+ * Find the highest set bit in value, and return a new value
+ * with only that bit set.
+ * @param value the value to examine
+ * @since 1.5
+ */
+ public static long highestOneBit(long value)
+ {
+ value |= value >>> 1;
+ value |= value >>> 2;
+ value |= value >>> 4;
+ value |= value >>> 8;
+ value |= value >>> 16;
+ value |= value >>> 32;
+ return value ^ (value >>> 1);
+ }
+
+ /**
+ * Return the number of leading zeros in value.
+ * @param value the value to examine
+ * @since 1.5
+ */
+ public static int numberOfLeadingZeros(long value)
+ {
+ value |= value >>> 1;
+ value |= value >>> 2;
+ value |= value >>> 4;
+ value |= value >>> 8;
+ value |= value >>> 16;
+ value |= value >>> 32;
+ return bitCount(~value);
+ }
+
+ /**
+ * Find the lowest set bit in value, and return a new value
+ * with only that bit set.
+ * @param value the value to examine
+ * @since 1.5
+ */
+ public static long lowestOneBit(long value)
+ {
+ // Classic assembly trick.
+ return value & - value;
+ }
+
+ /**
+ * Find the number of trailing zeros in value.
+ * @param value the value to examine
+ * @since 1.5
+ */
+ public static int numberOfTrailingZeros(long value)
+ {
+ return bitCount((value & -value) - 1);
+ }
+
+ /**
+ * Return 1 if x is positive, -1 if it is negative, and 0 if it is
+ * zero.
+ * @param x the value to examine
+ * @since 1.5
+ */
+ public static int signum(long x)
+ {
+ return x < 0 ? -1 : (x > 0 ? 1 : 0);
+ }
+
+ /**
+ * Reverse the bytes in val.
+ * @since 1.5
+ */
+ public static long reverseBytes(long val)
+ {
+ int hi = Integer.reverseBytes((int) val);
+ int lo = Integer.reverseBytes((int) (val >>> 32));
+ return (((long) hi) << 32) | lo;
+ }
+
+ /**
+ * Reverse the bits in val.
+ * @since 1.5
+ */
+ public static long reverse(long val)
+ {
+ long hi = Integer.reverse((int) val) & 0xffffffffL;
+ long lo = Integer.reverse((int) (val >>> 32)) & 0xffffffffL;
+ return (hi << 32) | lo;
+ }
+
+ /**
* Helper for converting unsigned numbers to String.
*
* @param num the number