1 files changed, 72 insertions, 0 deletions
diff --git a/lttng/org.eclipse.linuxtools.ctf.core/src/org/eclipse/linuxtools/internal/ctf/core/event/CTFCallsiteComparator.java b/lttng/org.eclipse.linuxtools.ctf.core/src/org/eclipse/linuxtools/internal/ctf/core/event/CTFCallsiteComparator.java
new file mode 100644
index 0000000000..ab36f0af9d
--- /dev/null
+++ b/lttng/org.eclipse.linuxtools.ctf.core/src/org/eclipse/linuxtools/internal/ctf/core/event/CTFCallsiteComparator.java
@@ -0,0 +1,72 @@
+/*******************************************************************************
+ * Copyright (c) 2013 Ericsson
+ *
+ * All rights reserved. This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License v1.0 which
+ * accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *  Simon Delisle - Initial implementation
+ *******************************************************************************/
+
+package org.eclipse.linuxtools.internal.ctf.core.event;
+
+import java.util.Comparator;
+
+import org.eclipse.linuxtools.ctf.core.event.CTFCallsite;
+
+/**
+ * Comparator for CTFCallsite
+ *
+ * @author Simon Delisle
+ * @since 3.0
+ *
+ */
+public class CTFCallsiteComparator implements Comparator<CTFCallsite> {
+
+    private static final long MASK32 = 0x00000000ffffffffL;
+
+    /*
+     * The callsites will be sorted by calling addresses. To do this we take IPs
+     * (instruction pointers) and compare them. Java only supports signed
+     * operation and since memory addresses are unsigned, we will convert the
+     * longs into integers that contain the high and low bytes and compare them.
+     */
+    @Override
+    public int compare(CTFCallsite o1, CTFCallsite o2) {
+        /*
+         * mask32 is 32 zeros followed by 32 ones, when we bitwise and this it
+         * will return the lower 32 bits
+         */
+
+        long other = o2.getIp();
+        /*
+         * To get a high int: we downshift by 32 and bitwise and with the mask
+         * to get rid of the sign
+         *
+         * To get the low int: we bitwise and with the mask.
+         */
+        long otherHigh = (other >> 32) & MASK32;
+        long otherLow = other & MASK32;
+        long ownHigh = (o1.getIp() >> 32) & MASK32;
+        long ownLow = o1.getIp() & MASK32;
+        /* are the high values different, if so ignore the lower values */
+        if (ownHigh > otherHigh) {
+            return 1;
+        }
+        if (ownHigh < otherHigh ) {
+            return -1;
+        }
+        /* the high values are the same, compare the lower values */
+        if (ownLow > otherLow) {
+            return 1;
+        }
+        if (ownLow < otherLow) {
+            return -1;
+        }
+        /* the values are identical */
+        return 0;
+    }
+
+}