[Emu][onos-2603] - Implement LinkState Link attributes

Change-Id: I452675ab9e3cf884924212b7114659dfc9118ef3

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.bgpio.types.attr;
+
+import java.util.Arrays;
+import java.util.Objects;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.onosproject.bgpio.exceptions.BGPParseException;
+import org.onosproject.bgpio.types.BGPErrorType;
+import org.onosproject.bgpio.types.BGPValueType;
+import org.onosproject.bgpio.util.Validation;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.MoreObjects;
+
+/**
+ * Implements BGP unreserved bandwidth attribute.
+ */
+public class BgpLinkAttrUnRsrvdLinkBandwidth implements BGPValueType {
+
+    protected static final Logger log = LoggerFactory
+            .getLogger(BgpLinkAttrUnRsrvdLinkBandwidth.class);
+
+    public static final int MAX_BANDWIDTH_LEN = 4;
+    public static final int NO_OF_BITS = 8;
+    public static final int NO_OF_PRIORITY = 8;
+
+    public short sType;
+
+    /* ISIS administrative group */
+    private float[] maxUnResBandwidth;
+
+    /**
+     * Constructor to initialize the values.
+     *
+     * @param maxUnResBandwidth Maximum Unreserved bandwidth
+     * @param sType returns the tag value
+     */
+    BgpLinkAttrUnRsrvdLinkBandwidth(float[] maxUnResBandwidth, short sType) {
+        this.maxUnResBandwidth = Arrays.copyOf(maxUnResBandwidth,
+                                               maxUnResBandwidth.length);
+        this.sType = sType;
+    }
+
+    /**
+     * Reads the BGP link attributes of Maximum link bandwidth.
+     *
+     * @param cb Channel buffer
+     * @return object of type BgpLinkAttrMaxLinkBandwidth
+     * @throws BGPParseException while parsing BgpLinkAttrMaxLinkBandwidth
+     */
+    public static BgpLinkAttrUnRsrvdLinkBandwidth read(ChannelBuffer cb,
+                                                       short sType)
+                                                               throws BGPParseException {
+        float[] maxUnResBandwidth;
+        short lsAttrLength = cb.readShort();
+
+        if ((lsAttrLength != MAX_BANDWIDTH_LEN * NO_OF_PRIORITY)
+                || (cb.readableBytes() < lsAttrLength)) {
+            Validation.validateLen(BGPErrorType.UPDATE_MESSAGE_ERROR,
+                                   BGPErrorType.ATTRIBUTE_LENGTH_ERROR,
+                                   lsAttrLength);
+        }
+
+        maxUnResBandwidth = new float[NO_OF_PRIORITY];
+        for (int i = 0; i < NO_OF_PRIORITY; i++) {
+            maxUnResBandwidth[i] = ieeeToFloatRead(cb.readInt()) * NO_OF_BITS;
+        }
+
+        return new BgpLinkAttrUnRsrvdLinkBandwidth(maxUnResBandwidth, sType);
+    }
+
+    /**
+     * Returns maximum unreserved bandwidth.
+     *
+     * @return unreserved bandwidth.
+     */
+    float[] getLinkAttrUnRsrvdLinkBandwidth() {
+        return maxUnResBandwidth;
+    }
+
+    /**
+     * Parse the IEEE floating point notation and returns it in normal float.
+     *
+     * @param iVal IEEE floating point number
+     * @return normal float
+     */
+    static float ieeeToFloatRead(int  iVal) {
+        iVal = (((iVal & 0xFF) << 24) | ((iVal & 0xFF00) << 8)
+                | ((iVal & 0xFF0000) >> 8) | ((iVal >> 24) & 0xFF));
+
+        return Float.intBitsToFloat(iVal);
+    }
+
+    @Override
+    public short getType() {
+        return this.sType;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(maxUnResBandwidth);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj instanceof BgpLinkAttrUnRsrvdLinkBandwidth) {
+            BgpLinkAttrUnRsrvdLinkBandwidth other = (BgpLinkAttrUnRsrvdLinkBandwidth) obj;
+            return Objects.equals(maxUnResBandwidth, other.maxUnResBandwidth);
+        }
+        return false;
+    }
+
+    @Override
+    public int write(ChannelBuffer cb) {
+        // TODO This will be implemented in the next version
+        return 0;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass()).omitNullValues()
+                .add("maxUnResBandwidth", maxUnResBandwidth).toString();
+    }
+}