Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.scl.compiler / src / org / simantics / scl / compiler / types / util / Polarity.java

diff --git a/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/types/util/Polarity.java b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/types/util/Polarity.java
new file mode 100644 (file)
index 0000000..6789259
--- /dev/null
+++ b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/types/util/Polarity.java
@@ -0,0 +1,47 @@
+package org.simantics.scl.compiler.types.util;
+
+
+public enum Polarity {
+    NO_POLARITY("?"),
+    POSITIVE("+"),
+    NEGATIVE("-"),
+    BIPOLAR("=");
+    
+    private Polarity(String symbol) {
+        this.symbol = symbol;
+    }
+
+    private final String symbol;
+    private Polarity flipped;
+    private Polarity[] combi = new Polarity[4];
+    
+    static {
+        for(int ia=0;ia<4;++ia) {
+            Polarity a = values()[ia];
+            a.flipped = values()[ ((ia&1)<<1) | ((ia&2)>>1) ];
+            for(int ib=0;ib<4;++ib) {
+                a.combi[ib] = values()[ia | ib];
+            }
+        }
+    }
+    
+    public Polarity flip() {
+        return flipped;
+    }
+    
+    public Polarity add(Polarity other) {
+        return combi[other.ordinal()];
+    }
+
+    public String getSymbol() {
+        return symbol;
+    }
+    
+    public boolean isPositive() {
+        return (ordinal()&1) != 0;                
+    }
+    
+    public boolean isNegative() {
+        return (ordinal()&2) != 0;
+    }
+}