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 /*

  * ====================================================================

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  * ====================================================================

  *

  * This software consists of voluntary contributions made by many

  * individuals on behalf of the Apache Software Foundation.  For more

  * information on the Apache Software Foundation, please see

  * <http://www.apache.org/>.

  *

  */

 package ch.boye.httpclientandroidlib.util;

 import java.io.Serializable;

 import ch.boye.httpclientandroidlib.protocol.HTTP;

 /**

  * A resizable char array.

  *

  * @since 4.0

  */

 public final class CharArrayBuffer implements Serializable {

     private static final long serialVersionUID = -6208952725094867135L;

     private char[] buffer;

     private int len;

     /**

      * Creates an instance of {@link CharArrayBuffer} with the given initial

      * capacity.

      *

      * @param capacity the capacity

      */

     public CharArrayBuffer(int capacity) {

         super();

         if (capacity < 0) {

             throw new IllegalArgumentException("Buffer capacity may not be negative");

         }

         this.buffer = new char[capacity];

     }

     private void expand(int newlen) {

         char newbuffer[] = new char[Math.max(this.buffer.length << 1, newlen)];

         System.arraycopy(this.buffer, 0, newbuffer, 0, this.len);

         this.buffer = newbuffer;

     }

     /**

      * Appends <code>len</code> chars to this buffer from the given source

      * array starting at index <code>off</code>. The capacity of the buffer

      * is increased, if necessary, to accommodate all <code>len</code> chars.

      *

      * @param   b        the chars to be appended.

      * @param   off      the index of the first char to append.

      * @param   len      the number of chars to append.

      * @throws IndexOutOfBoundsException if <code>off</code> is out of

      * range, <code>len</code> is negative, or

      * <code>off</code> + <code>len</code> is out of range.

      */

     public void append(final char[] b, int off, int len) {

         if (b == null) {

             return;

         }

         if ((off < 0) || (off > b.length) || (len < 0) ||

                 ((off + len) < 0) || ((off + len) > b.length)) {

             throw new IndexOutOfBoundsException("off: "+off+" len: "+len+" b.length: "+b.length);

         }

         if (len == 0) {

             return;

         }

         int newlen = this.len + len;

         if (newlen > this.buffer.length) {

             expand(newlen);

         }

         System.arraycopy(b, off, this.buffer, this.len, len);

         this.len = newlen;

     }

     /**

      * Appends chars of the given string to this buffer. The capacity of the

      * buffer is increased, if necessary, to accommodate all chars.

      *

      * @param str    the string.

      */

     public void append(String str) {

         if (str == null) {

             str = "null";

         }

         int strlen = str.length();

         int newlen = this.len + strlen;

         if (newlen > this.buffer.length) {

             expand(newlen);

         }

         str.getChars(0, strlen, this.buffer, this.len);

         this.len = newlen;

     }

     /**

      * Appends <code>len</code> chars to this buffer from the given source

      * buffer starting at index <code>off</code>. The capacity of the

      * destination buffer is increased, if necessary, to accommodate all

      * <code>len</code> chars.

      *

      * @param   b        the source buffer to be appended.

      * @param   off      the index of the first char to append.

      * @param   len      the number of chars to append.

      * @throws IndexOutOfBoundsException if <code>off</code> is out of

      * range, <code>len</code> is negative, or

      * <code>off</code> + <code>len</code> is out of range.

      */

     public void append(final CharArrayBuffer b, int off, int len) {

         if (b == null) {

             return;

         }

         append(b.buffer, off, len);

     }

     /**

      * Appends all chars to this buffer from the given source buffer starting

      * at index <code>0</code>. The capacity of the destination buffer is

      * increased, if necessary, to accommodate all {@link #length()} chars.

      *

      * @param   b        the source buffer to be appended.

      */

     public void append(final CharArrayBuffer b) {

         if (b == null) {

             return;

         }

         append(b.buffer,0, b.len);

     }

     /**

      * Appends <code>ch</code> char to this buffer. The capacity of the buffer

      * is increased, if necessary, to accommodate the additional char.

      *

      * @param   ch        the char to be appended.

      */

     public void append(char ch) {

         int newlen = this.len + 1;

         if (newlen > this.buffer.length) {

             expand(newlen);

         }

         this.buffer[this.len] = ch;

         this.len = newlen;

     }

     /**

      * Appends <code>len</code> bytes to this buffer from the given source

      * array starting at index <code>off</code>. The capacity of the buffer

      * is increased, if necessary, to accommodate all <code>len</code> bytes.

      * <p>

      * The bytes are converted to chars using simple cast.

      *

      * @param   b        the bytes to be appended.

      * @param   off      the index of the first byte to append.

      * @param   len      the number of bytes to append.

      * @throws IndexOutOfBoundsException if <code>off</code> is out of

      * range, <code>len</code> is negative, or

      * <code>off</code> + <code>len</code> is out of range.

      */

     public void append(final byte[] b, int off, int len) {

         if (b == null) {

             return;

         }

         if ((off < 0) || (off > b.length) || (len < 0) ||

                 ((off + len) < 0) || ((off + len) > b.length)) {

             throw new IndexOutOfBoundsException("off: "+off+" len: "+len+" b.length: "+b.length);

         }

         if (len == 0) {

             return;

         }

         int oldlen = this.len;

         int newlen = oldlen + len;

         if (newlen > this.buffer.length) {

             expand(newlen);

         }

         for (int i1 = off, i2 = oldlen; i2 < newlen; i1++, i2++) {

             this.buffer[i2] = (char) (b[i1] & 0xff);

         }

         this.len = newlen;

     }

     /**

      * Appends <code>len</code> bytes to this buffer from the given source

      * array starting at index <code>off</code>. The capacity of the buffer

      * is increased, if necessary, to accommodate all <code>len</code> bytes.

      * <p>

      * The bytes are converted to chars using simple cast.

      *

      * @param   b        the bytes to be appended.

      * @param   off      the index of the first byte to append.

      * @param   len      the number of bytes to append.

      * @throws IndexOutOfBoundsException if <code>off</code> is out of

      * range, <code>len</code> is negative, or

      * <code>off</code> + <code>len</code> is out of range.

      */

     public void append(final ByteArrayBuffer b, int off, int len) {

         if (b == null) {

             return;

         }

         append(b.buffer(), off, len);

     }

     /**

      * Appends chars of the textual representation of the given object to this

      * buffer. The capacity of the buffer is increased, if necessary, to

      * accommodate all chars.

      *

      * @param obj    the object.

      */

     public void append(final Object obj) {

         append(String.valueOf(obj));

     }

     /**

      * Clears content of the buffer. The underlying char array is not resized.

      */

     public void clear() {

         this.len = 0;

     }

     /**

      * Converts the content of this buffer to an array of chars.

      *

      * @return char array

      */

     public char[] toCharArray() {

         char[] b = new char[this.len];

         if (this.len > 0) {

             System.arraycopy(this.buffer, 0, b, 0, this.len);

         }

         return b;

     }

     /**

      * Returns the <code>char</code> value in this buffer at the specified

      * index. The index argument must be greater than or equal to

      * <code>0</code>, and less than the length of this buffer.

      *

      * @param      i   the index of the desired char value.

      * @return     the char value at the specified index.

      * @throws     IndexOutOfBoundsException  if <code>index</code> is

      *             negative or greater than or equal to {@link #length()}.

      */

     public char charAt(int i) {

         return this.buffer[i];

     }

     /**

      * Returns reference to the underlying char array.

      *

      * @return the char array.

      */

     public char[] buffer() {

         return this.buffer;

     }

     /**

      * Returns the current capacity. The capacity is the amount of storage

      * available for newly appended chars, beyond which an allocation will

      * occur.

      *

      * @return  the current capacity

      */

     public int capacity() {

         return this.buffer.length;

     }

     /**

      * Returns the length of the buffer (char count).

      *

      * @return  the length of the buffer

      */

     public int length() {

         return this.len;

     }

     /**

      * Ensures that the capacity is at least equal to the specified minimum.

      * If the current capacity is less than the argument, then a new internal

      * array is allocated with greater capacity. If the <code>required</code>

      * argument is non-positive, this method takes no action.

      *

      * @param   required   the minimum required capacity.

      */

     public void ensureCapacity(int required) {

         if (required <= 0) {

             return;

         }

         int available = this.buffer.length - this.len;

         if (required > available) {

             expand(this.len + required);

         }

     }

     /**

      * Sets the length of the buffer. The new length value is expected to be

      * less than the current capacity and greater than or equal to

      * <code>0</code>.

      *

      * @param      len   the new length

      * @throws     IndexOutOfBoundsException  if the

      *               <code>len</code> argument is greater than the current

      *               capacity of the buffer or less than <code>0</code>.

      */

     public void setLength(int len) {

         if (len < 0 || len > this.buffer.length) {

             throw new IndexOutOfBoundsException("len: "+len+" < 0 or > buffer len: "+this.buffer.length);

         }

         this.len = len;

     }

     /**

      * Returns <code>true</code> if this buffer is empty, that is, its

      * {@link #length()} is equal to <code>0</code>.

      * @return <code>true</code> if this buffer is empty, <code>false</code>

      *   otherwise.

      */

     public boolean isEmpty() {

         return this.len == 0;

     }

     /**

      * Returns <code>true</code> if this buffer is full, that is, its

      * {@link #length()} is equal to its {@link #capacity()}.

      * @return <code>true</code> if this buffer is full, <code>false</code>

      *   otherwise.

      */

     public boolean isFull() {

         return this.len == this.buffer.length;

     }

     /**

      * Returns the index within this buffer of the first occurrence of the

      * specified character, starting the search at the specified

      * <code>beginIndex</code> and finishing at <code>endIndex</code>.

      * If no such character occurs in this buffer within the specified bounds,

      * <code>-1</code> is returned.

      * <p>

      * There is no restriction on the value of <code>beginIndex</code> and

      * <code>endIndex</code>. If <code>beginIndex</code> is negative,

      * it has the same effect as if it were zero. If <code>endIndex</code> is

      * greater than {@link #length()}, it has the same effect as if it were

      * {@link #length()}. If the <code>beginIndex</code> is greater than

      * the <code>endIndex</code>, <code>-1</code> is returned.

      *

      * @param   ch          the char to search for.

      * @param   beginIndex   the index to start the search from.

      * @param   endIndex   the index to finish the search at.

      * @return  the index of the first occurrence of the character in the buffer

      *   within the given bounds, or <code>-1</code> if the character does

      *   not occur.

      */

     public int indexOf(int ch, int beginIndex, int endIndex) {

         if (beginIndex < 0) {

             beginIndex = 0;

         }

         if (endIndex > this.len) {

             endIndex = this.len;

         }

         if (beginIndex > endIndex) {

             return -1;

         }

         for (int i = beginIndex; i < endIndex; i++) {

             if (this.buffer[i] == ch) {

                 return i;

             }

         }

         return -1;

     }

     /**

      * Returns the index within this buffer of the first occurrence of the

      * specified character, starting the search at <code>0</code> and finishing

      * at {@link #length()}. If no such character occurs in this buffer within

      * those bounds, <code>-1</code> is returned.

      *

      * @param   ch          the char to search for.

      * @return  the index of the first occurrence of the character in the

      *   buffer, or <code>-1</code> if the character does not occur.

      */

     public int indexOf(int ch) {

         return indexOf(ch, 0, this.len);

     }

     /**

      * Returns a substring of this buffer. The substring begins at the specified

      * <code>beginIndex</code> and extends to the character at index

      * <code>endIndex - 1</code>.

      *

      * @param      beginIndex   the beginning index, inclusive.

      * @param      endIndex     the ending index, exclusive.

      * @return     the specified substring.

      * @exception  StringIndexOutOfBoundsException  if the

      *             <code>beginIndex</code> is negative, or

      *             <code>endIndex</code> is larger than the length of this

      *             buffer, or <code>beginIndex</code> is larger than

      *             <code>endIndex</code>.

      */

     public String substring(int beginIndex, int endIndex) {

         return new String(this.buffer, beginIndex, endIndex - beginIndex);

     }

     /**

      * Returns a substring of this buffer with leading and trailing whitespace

      * omitted. The substring begins with the first non-whitespace character

      * from <code>beginIndex</code> and extends to the last

      * non-whitespace character with the index lesser than

      * <code>endIndex</code>.

      *

      * @param      beginIndex   the beginning index, inclusive.

      * @param      endIndex     the ending index, exclusive.

      * @return     the specified substring.

      * @exception  IndexOutOfBoundsException  if the

      *             <code>beginIndex</code> is negative, or

      *             <code>endIndex</code> is larger than the length of this

      *             buffer, or <code>beginIndex</code> is larger than

      *             <code>endIndex</code>.

      */

     public String substringTrimmed(int beginIndex, int endIndex) {

         if (beginIndex < 0) {

             throw new IndexOutOfBoundsException("Negative beginIndex: "+beginIndex);

         }

         if (endIndex > this.len) {

             throw new IndexOutOfBoundsException("endIndex: "+endIndex+" > length: "+this.len);

         }

         if (beginIndex > endIndex) {

             throw new IndexOutOfBoundsException("beginIndex: "+beginIndex+" > endIndex: "+endIndex);

         }

         while (beginIndex < endIndex && HTTP.isWhitespace(this.buffer[beginIndex])) {

             beginIndex++;

         }

         while (endIndex > beginIndex && HTTP.isWhitespace(this.buffer[endIndex - 1])) {

             endIndex--;

         }

         return new String(this.buffer, beginIndex, endIndex - beginIndex);

     }

     public String toString() {

         return new String(this.buffer, 0, this.len);

     }

 }