1 files changed, 248 insertions, 0 deletions
diff --git a/libjava/classpath/external/jsr166/java/util/concurrent/atomic/AtomicLong.java b/libjava/classpath/external/jsr166/java/util/concurrent/atomic/AtomicLong.java
new file mode 100644
index 000000000..fa254ba62
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+++ b/libjava/classpath/external/jsr166/java/util/concurrent/atomic/AtomicLong.java
@@ -0,0 +1,248 @@
+/*
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/licenses/publicdomain
+ */
+
+package java.util.concurrent.atomic;
+import sun.misc.Unsafe;
+
+/**
+ * A <tt>long</tt> value that may be updated atomically.  See the
+ * {@link java.util.concurrent.atomic} package specification for
+ * description of the properties of atomic variables. An
+ * <tt>AtomicLong</tt> is used in applications such as atomically
+ * incremented sequence numbers, and cannot be used as a replacement
+ * for a {@link java.lang.Long}. However, this class does extend
+ * <tt>Number</tt> to allow uniform access by tools and utilities that
+ * deal with numerically-based classes.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ */
+public class AtomicLong extends Number implements java.io.Serializable {
+    private static final long serialVersionUID = 1927816293512124184L;
+
+    // setup to use Unsafe.compareAndSwapLong for updates
+    private static final Unsafe unsafe = Unsafe.getUnsafe();
+    private static final long valueOffset;
+
+    /**
+     * Records whether the underlying JVM supports lockless
+     * CompareAndSet for longs. While the unsafe.CompareAndSetLong
+     * method works in either case, some constructions should be
+     * handled at Java level to avoid locking user-visible locks.
+     */
+    static final boolean VM_SUPPORTS_LONG_CAS = VMSupportsCS8();
+
+    /**
+     * Returns whether underlying JVM supports lockless CompareAndSet
+     * for longs. Called only once and cached in VM_SUPPORTS_LONG_CAS.
+     */
+    private static native boolean VMSupportsCS8();
+
+    static {
+      try {
+        valueOffset = unsafe.objectFieldOffset
+            (AtomicLong.class.getDeclaredField("value"));
+      } catch (Exception ex) { throw new Error(ex); }
+    }
+
+    private volatile long value;
+
+    /**
+     * Creates a new AtomicLong with the given initial value.
+     *
+     * @param initialValue the initial value
+     */
+    public AtomicLong(long initialValue) {
+        value = initialValue;
+    }
+
+    /**
+     * Creates a new AtomicLong with initial value <tt>0</tt>.
+     */
+    public AtomicLong() {
+    }
+
+    /**
+     * Gets the current value.
+     *
+     * @return the current value
+     */
+    public final long get() {
+        return value;
+    }
+
+    /**
+     * Sets to the given value.
+     *
+     * @param newValue the new value
+     */
+    public final void set(long newValue) {
+        value = newValue;
+    }
+
+    /**
+     * Eventually sets to the given value.
+     *
+     * @param newValue the new value
+     * @since 1.6
+     */
+    public final void lazySet(long newValue) {
+        unsafe.putOrderedLong(this, valueOffset, newValue);
+    }
+
+    /**
+     * Atomically sets to the given value and returns the old value.
+     *
+     * @param newValue the new value
+     * @return the previous value
+     */
+    public final long getAndSet(long newValue) {
+        while (true) {
+            long current = get();
+            if (compareAndSet(current, newValue))
+                return current;
+        }
+    }
+
+    /**
+     * Atomically sets the value to the given updated value
+     * if the current value <tt>==</tt> the expected value.
+     *
+     * @param expect the expected value
+     * @param update the new value
+     * @return true if successful. False return indicates that
+     * the actual value was not equal to the expected value.
+     */
+    public final boolean compareAndSet(long expect, long update) {
+        return unsafe.compareAndSwapLong(this, valueOffset, expect, update);
+    }
+
+    /**
+     * Atomically sets the value to the given updated value
+     * if the current value <tt>==</tt> the expected value.
+     * May fail spuriously and does not provide ordering guarantees,
+     * so is only rarely an appropriate alternative to <tt>compareAndSet</tt>.
+     *
+     * @param expect the expected value
+     * @param update the new value
+     * @return true if successful.
+     */
+    public final boolean weakCompareAndSet(long expect, long update) {
+        return unsafe.compareAndSwapLong(this, valueOffset, expect, update);
+    }
+
+    /**
+     * Atomically increments by one the current value.
+     *
+     * @return the previous value
+     */
+    public final long getAndIncrement() {
+        while (true) {
+            long current = get();
+            long next = current + 1;
+            if (compareAndSet(current, next))
+                return current;
+        }
+    }
+
+    /**
+     * Atomically decrements by one the current value.
+     *
+     * @return the previous value
+     */
+    public final long getAndDecrement() {
+        while (true) {
+            long current = get();
+            long next = current - 1;
+            if (compareAndSet(current, next))
+                return current;
+        }
+    }
+
+    /**
+     * Atomically adds the given value to the current value.
+     *
+     * @param delta the value to add
+     * @return the previous value
+     */
+    public final long getAndAdd(long delta) {
+        while (true) {
+            long current = get();
+            long next = current + delta;
+            if (compareAndSet(current, next))
+                return current;
+        }
+    }
+
+    /**
+     * Atomically increments by one the current value.
+     *
+     * @return the updated value
+     */
+    public final long incrementAndGet() {
+        for (;;) {
+            long current = get();
+            long next = current + 1;
+            if (compareAndSet(current, next))
+                return next;
+        }
+    }
+
+    /**
+     * Atomically decrements by one the current value.
+     *
+     * @return the updated value
+     */
+    public final long decrementAndGet() {
+        for (;;) {
+            long current = get();
+            long next = current - 1;
+            if (compareAndSet(current, next))
+                return next;
+        }
+    }
+
+    /**
+     * Atomically adds the given value to the current value.
+     *
+     * @param delta the value to add
+     * @return the updated value
+     */
+    public final long addAndGet(long delta) {
+        for (;;) {
+            long current = get();
+            long next = current + delta;
+            if (compareAndSet(current, next))
+                return next;
+        }
+    }
+
+    /**
+     * Returns the String representation of the current value.
+     * @return the String representation of the current value.
+     */
+    public String toString() {
+        return Long.toString(get());
+    }
+
+
+    public int intValue() {
+        return (int)get();
+    }
+
+    public long longValue() {
+        return (long)get();
+    }
+
+    public float floatValue() {
+        return (float)get();
+    }
+
+    public double doubleValue() {
+        return (double)get();
+    }
+
+}