/*

  * #%L

  * BinaryElement.java - mongodb-async-driver - Allanbank Consulting, Inc.

  * %%

  * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.

  * %%

  * 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.

  * #L%

  */

 package com.allanbank.mongodb.bson.element;

 import static com.allanbank.mongodb.util.Assertions.assertNotNull;

 import java.io.IOException;

 import java.util.Arrays;

 import com.allanbank.mongodb.bson.Element;

 import com.allanbank.mongodb.bson.ElementType;

 import com.allanbank.mongodb.bson.Visitor;

 import com.allanbank.mongodb.bson.io.BsonInputStream;

 import com.allanbank.mongodb.bson.io.StringEncoder;

 /**

  * A wrapper for a BSON binary.

  * 

  * @api.yes This class is part of the driver's API. Public and protected members

  *          will be deprecated for at least 1 non-bugfix release (version

  *          numbers are <major>.<minor>.<bugfix>) before being

  *          removed or modified.

  * @copyright 2011-2013, Allanbank Consulting, Inc., All Rights Reserved

  */

 public class BinaryElement extends AbstractElement {

     /** The sub type used when no sub type is specified. */

     public static final byte DEFAULT_SUB_TYPE = 0;

     /** The BSON type for a binary. */

     public static final ElementType TYPE = ElementType.BINARY;

     /** Serialization version for the class. */

     private static final long serialVersionUID = 5864918707454038001L;

     /**

      * Computes and returns the number of bytes that are used to encode the

      * element.

      * 

      * @param name

      *            The name for the BSON array.

      * @param subType

      *            The sub-type of the binary data.

      * @param bytesLength

      *            The length of the binary array.

      * @return The size of the element when encoded in bytes.

      */

     private static long computeSize(final String name, final byte subType,

             final int bytesLength) {

         long result = 7; // type (1) + name null byte (1) + data length (4) +

                          // subtype (1).

         result += StringEncoder.utf8Size(name);

         result += bytesLength;

         if (subType == 2) {

             // Extra length field in subtype 2.

             result += 4;

         }

         return result;

     }

     /** The sub-type of the binary data. */

     private final byte mySubType;

     /** The BSON binary value. */

     private final byte[] myValue;

     /**

      * Constructs a new {@link BinaryElement}.

      * 

      * @param name

      *            The name for the BSON binary.

      * @param subType

      *            The sub-type of the binary data.

      * @param input

      *            The stream to read the data from.

      * @param length

      *            The number of bytes of data to read.

      * @throws IllegalArgumentException

      *             If the {@code name} is <code>null</code>.

      * @throws IOException

      *             If there is an error reading from {@code input} stream.

      */

     public BinaryElement(final String name, final byte subType,

             final BsonInputStream input, final int length) throws IOException {

         this(name, subType, input, length, computeSize(name, subType, length));

     }

     /**

      * Constructs a new {@link BinaryElement}.

      * 

      * @param name

      *            The name for the BSON binary.

      * @param subType

      *            The sub-type of the binary data.

      * @param input

      *            The stream to read the data from.

      * @param length

      *            The number of bytes of data to read.

      * @param size

      *            The size of the element when encoded in bytes. If not known

      *            then use the

      *            {@link BinaryElement#BinaryElement(String, byte, BsonInputStream, int)}

      *            constructor instead.

      * @throws IllegalArgumentException

      *             If the {@code name} is <code>null</code>.

      * @throws IOException

      *             If there is an error reading from {@code input} stream.

      */

     public BinaryElement(final String name, final byte subType,

             final BsonInputStream input, final int length, final long size)

             throws IOException {

         super(name, size);

         mySubType = subType;

         myValue = new byte[length];

         input.readFully(myValue);

     }

     /**

      * Constructs a new {@link BinaryElement}.

      * 

      * @param name

      *            The name for the BSON binary.

      * @param subType

      *            The sub-type of the binary data.

      * @param value

      *            The BSON binary value.

      * @throws IllegalArgumentException

      *             If the {@code name} or {@code value} is <code>null</code>.

      */

     public BinaryElement(final String name, final byte subType,

             final byte[] value) {

         this(name, subType, value, computeSize(name, subType,

                 (value == null) ? 0 : value.length));

     }

     /**

      * Constructs a new {@link BinaryElement}.

      * 

      * @param name

      *            The name for the BSON binary.

      * @param subType

      *            The sub-type of the binary data.

      * @param value

      *            The BSON binary value.

      * @param size

      *            The size of the element when encoded in bytes. If not known

      *            then use the

      *            {@link BinaryElement#BinaryElement(String, byte, byte[])}

      *            constructor instead.

      * @throws IllegalArgumentException

      *             If the {@code name} or {@code value} is <code>null</code>.

      */

     public BinaryElement(final String name, final byte subType,

             final byte[] value, final long size) {

         super(name, size);

         assertNotNull(value,

                 "Binary element's value cannot be null.  Add a null element instead.");

         mySubType = subType;

         myValue = value.clone();

     }

     /**

      * Constructs a new {@link BinaryElement}. Uses the

      * {@link #DEFAULT_SUB_TYPE}.

      * 

      * @param name

      *            The name for the BSON binary.

      * @param value

      *            The BSON binary value.

      * @throws IllegalArgumentException

      *             If the {@code name} or {@code value} is <code>null</code>.

      */

     public BinaryElement(final String name, final byte[] value) {

         this(name, DEFAULT_SUB_TYPE, value);

     }

     /**

      * Accepts the visitor and calls the {@link Visitor#visitBinary} method.

      * 

      * @see Element#accept(Visitor)

      */

     @Override

     public void accept(final Visitor visitor) {

         visitor.visitBinary(getName(), getSubType(), getValue());

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to compare the sub-types and bytes if the base class

      * comparison is equals.

      * </p>

      */

     @Override

     public int compareTo(final Element otherElement) {

         int result = super.compareTo(otherElement);

         if (result == 0) {

             final BinaryElement other = (BinaryElement) otherElement;

             result = mySubType - other.mySubType;

             if (result == 0) {

                 final int length = Math.min(myValue.length,

                         other.myValue.length);

                 for (int i = 0; i < length; ++i) {

                     result = myValue[i] - other.myValue[i];

                     if (result != 0) {

                         return result;

                     }

                 }

                 result = myValue.length - other.myValue.length;

             }

         }

         return result;

     }

     /**

      * Determines if the passed object is of this same type as this object and

      * if so that its fields are equal.

      * 

      * @param object

      *            The object to compare to.

      * 

      * @see java.lang.Object#equals(java.lang.Object)

      */

     @Override

     public boolean equals(final Object object) {

         boolean result = false;

         if (this == object) {

             result = true;

         }

         else if ((object != null) && (getClass() == object.getClass())) {

             final BinaryElement other = (BinaryElement) object;

             result = super.equals(object) && (mySubType == other.mySubType)

                     && Arrays.equals(myValue, other.myValue);

         }

         return result;

     }

     /**

      * Returns the byte value at the specified offset.

      * 

      * @param offset

      *            The offset of the desired value.

      * @return The byte value at the offset.

      * @throws ArrayIndexOutOfBoundsException

      *             If the offset is not in the range [0, {@link #length()}).

      */

     public final byte get(final int offset) {

         return myValue[offset];

     }

     /**

      * Return the binary sub-type.

      * 

      * @return The binary sub-type.

      */

     public byte getSubType() {

         return mySubType;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public ElementType getType() {

         return TYPE;

     }

     /**

      * Returns the BSON binary value. For safety reasons this method clones the

      * internal byte array. To avoid the copying of the bytes use the

      * {@link #length()} and {@link #get(int)} methods to access each byte

      * value.

      * 

      * @return The BSON binary value.

      */

     public byte[] getValue() {

         return myValue.clone();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Returns a byte[].

      * </p>

      * <p>

      * <b>Note:</b> This value will not be recreated is a Object-->Element

      * conversion. The sub type is lost in this conversion to an {@link Object}.

      * </p>

      * <p>

      * <em>Implementation Note:</em> The return type cannot be a byte[] here as

      * {@link UuidElement} returns a {@link java.util.UUID}.

      * </p>

      */

     @Override

     public Object getValueAsObject() {

         return getValue();

     }

     /**

      * Computes a reasonable hash code.

      * 

      * @return The hash code value.

      */

     @Override

     public int hashCode() {

         int result = 1;

         result = (31 * result) + super.hashCode();

         result = (31 * result) + mySubType;

         result = (31 * result) + Arrays.hashCode(myValue);

         return result;

     }

     /**

      * Returns the length of the contained byte array.

      * 

      * @return The length of the contained byte array.

      */

     public final int length() {

         return myValue.length;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Returns a new {@link BinaryElement}.

      * </p>

      */

     @Override

     public BinaryElement withName(final String name) {

         if (getName().equals(name)) {

             return this;

         }

         return new BinaryElement(name, mySubType, myValue);

     }

 }