1 files changed, 91 insertions, 0 deletions
diff --git a/src/main/java/com/it_jaros/jscanner/PortRange.java b/src/main/java/com/it_jaros/jscanner/PortRange.java
new file mode 100644
index 0000000..dd67176
--- /dev/null
+++ b/src/main/java/com/it_jaros/jscanner/PortRange.java
@@ -0,0 +1,91 @@
+package com.it_jaros.jscanner;
+
+import java.util.BitSet;
+import java.util.NoSuchElementException;
+
+public class PortRange {
+
+    public static final int MIN_PORT = 1;
+    public static final int MAX_PORT = 65535;
+    private final BitSet specifiedPorts = new BitSet(MAX_PORT);
+    private final BitSet availablePorts = new BitSet(MAX_PORT);
+
+    private int cursor;
+    private int done = 0;
+
+    public PortRange(String ports) {
+        if (ports == null || "".equals(ports)) {
+            // keep defaults
+            specifiedPorts.set(1, 1024 + 1);
+            return;
+        }
+
+        String[] splitComma = ports.split(",");
+        for (String commaValue : splitComma) {
+            if (commaValue.contains("-")) {
+                String[] rangeValue = commaValue.split("-");
+                if (rangeValue.length > 2) {
+                    throw new IllegalArgumentException(String.format("Argument contains too many '-'' %s", commaValue));
+                }
+
+                int start = Integer.parseInt(rangeValue[0]);
+                int end = Integer.parseInt(rangeValue[1]);
+                checkValues(start, end);
+                specifiedPorts.set(start, end + 1);
+            } else {
+                int port = Integer.parseInt(commaValue);
+                checkValue(port);
+                specifiedPorts.set(Integer.parseInt(commaValue));
+            }
+        }
+
+        availablePorts.or(specifiedPorts);
+        cursor = availablePorts.nextSetBit(MIN_PORT);
+    }
+
+    private void checkValues(int start, int end) {
+        checkValue(start);
+        checkValue(end);
+
+        if (start >= end) {
+            throw new IllegalArgumentException(
+                    String.format("Start value cannot be equal or bigger than end value '%s >= %s'", start, end));
+        }
+    }
+
+    private void checkValue(int port) {
+        if (port < MIN_PORT) {
+            throw new IllegalArgumentException(
+                    String.format("Start value smaller than allowed range %s < %s", port, MIN_PORT));
+        }
+
+        if (port > MAX_PORT) {
+            throw new IllegalArgumentException(
+                    String.format("End value bigger than allowed range %s > %s", port, MAX_PORT));
+        }
+    }
+
+    public int next() {
+        int p = availablePorts.nextSetBit(cursor);
+        if (p > 0) {
+            availablePorts.clear(p);
+            cursor = p + 1;
+            done++;
+            return p;
+        }
+
+        throw new NoSuchElementException("Reached end of port range");
+    }
+
+    public boolean hasNext() {
+        return availablePorts.nextSetBit(cursor) > 0;
+    }
+
+    public int getTotal() {
+        return specifiedPorts.cardinality();
+    }
+
+    public int getDone() {
+        return done;
+    }
+}