1 files changed, 103 insertions, 0 deletions
diff --git a/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/util/HashCodeUtils.java b/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/util/HashCodeUtils.java
new file mode 100644
index 0000000000..b8fa81af27
--- /dev/null
+++ b/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/util/HashCodeUtils.java
@@ -0,0 +1,103 @@
+package org.checkerframework.dataflow.util;
+
+/**
+ * Utility class to implement the {@code hashCode} method.
+ *
+ * @author Stefan Heule
+ *
+ */
+public class HashCodeUtils {
+
+    /** Odd prime number. */
+    private static int prime = 31;
+
+    /** Seed. */
+    private static int seed = 17;
+
+    /** Add a boolean value to a given hash. */
+    public static int hash(int hash, boolean item) {
+        return hash * prime + (item ? 1 : 0);
+    }
+
+    /** Add a char value to a given hash. */
+    public static int hash(int hash, char item) {
+        return hash * prime + item;
+    }
+
+    /** Add an int value to a given hash. */
+    public static int hash(int hash, int item) {
+        return hash * prime + item;
+    }
+
+    /** Add a long value to a given hash. */
+    public static int hash(int hash, long item) {
+        return hash * prime + (int) (item ^ (item >>> 32));
+    }
+
+    /** Add a float value to a given hash. */
+    public static int hash(int hash, float item) {
+        return hash * prime + Float.floatToIntBits(item);
+    }
+
+    /** Add a double value to a given hash. */
+    public static int hash(int hash, double item) {
+        long l = Double.doubleToLongBits(item);
+        return seed * prime + (int) (l ^ (l >>> 32));
+    }
+
+    /** Add an object to a given hash. */
+    public static int hash(int hash, Object item) {
+        if (item == null) {
+            return hash * prime;
+        }
+        return hash * prime + item.hashCode();
+    }
+
+    /** Hash a boolean value. */
+    public static int hash(boolean item) {
+        return (item ? 1 : 0);
+    }
+
+    /** Hash a char value. */
+    public static int hash(char item) {
+        return item;
+    }
+
+    /** Hash an int value. */
+    public static int hash(int item) {
+        return item;
+    }
+
+    /** Hash a long value. */
+    public static int hash(long item) {
+        return (int) (item ^ (item >>> 32));
+    }
+
+    /** Hash a float value. */
+    public static int hash(float item) {
+        return Float.floatToIntBits(item);
+    }
+
+    /** Hash a double value. */
+    public static int hash(double item) {
+        long l = Double.doubleToLongBits(item);
+        return (int) (l ^ (l >>> 32));
+    }
+
+    /** Hash an object. */
+    public static int hash(Object item) {
+        if (item == null) {
+            return 0;
+        }
+        return item.hashCode();
+    }
+
+    /** Hash multiple objects. */
+    public static int hash(Object... items) {
+        int result = seed;
+        for (Object item : items) {
+            result = result * prime + (item == null ? 0 : item.hashCode());
+        }
+        return result;
+    }
+}