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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
 * .
 *
 */

package org.apache.http.util;

import java.io.Serializable;
import java.nio.CharBuffer;

import org.apache.http.protocol.HTTP;

/**
 * A resizable char array.
 *
 * @since 4.0
 */
public final class CharArrayBuffer implements CharSequence, 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(final int capacity) {
        super();
        Args.notNegative(capacity, "Buffer capacity");
        this.buffer = new char[capacity];
    }

    private void expand(final int newlen) {
        final 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} chars to this buffer from the given source
     * array starting at index {@code off}. The capacity of the buffer
     * is increased, if necessary, to accommodate all {@code len} 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} is out of
     * range, {@code len} is negative, or
     * {@code off} + {@code len} is out of range.
     */
    public void append(final char[] b, final int off, final 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;
        }
        final 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(final String str) {
        final String s = str != null ? str : "null";
        final int strlen = s.length();
        final int newlen = this.len + strlen;
        if (newlen > this.buffer.length) {
            expand(newlen);
        }
        s.getChars(0, strlen, this.buffer, this.len);
        this.len = newlen;
    }

    /**
     * Appends {@code len} chars to this buffer from the given source
     * buffer starting at index {@code off}. The capacity of the
     * destination buffer is increased, if necessary, to accommodate all
     * {@code len} 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} is out of
     * range, {@code len} is negative, or
     * {@code off} + {@code len} is out of range.
     */
    public void append(final CharArrayBuffer b, final int off, final 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}. 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} 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(final char ch) {
        final int newlen = this.len + 1;
        if (newlen > this.buffer.length) {
            expand(newlen);
        }
        this.buffer[this.len] = ch;
        this.len = newlen;
    }

    /**
     * Appends {@code len} bytes to this buffer from the given source
     * array starting at index {@code off}. The capacity of the buffer
     * is increased, if necessary, to accommodate all {@code len} bytes.
     * 

* 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} is out of * range, {@code len} is negative, or * {@code off} + {@code len} is out of range. */ public void append(final byte[] b, final int off, final 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; } final int oldlen = this.len; final 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} bytes to this buffer from the given source * array starting at index {@code off}. The capacity of the buffer * is increased, if necessary, to accommodate all {@code len} bytes. *

* 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} is out of * range, {@code len} is negative, or * {@code off} + {@code len} is out of range. */ public void append(final ByteArrayBuffer b, final int off, final 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() { final 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} value in this buffer at the specified * index. The index argument must be greater than or equal to * {@code 0}, 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} is * negative or greater than or equal to {@link #length()}. */ @Override public char charAt(final 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 */ @Override 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} * argument is non-positive, this method takes no action. * * @param required the minimum required capacity. */ public void ensureCapacity(final int required) { if (required <= 0) { return; } final 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}. * * @param len the new length * @throws IndexOutOfBoundsException if the * {@code len} argument is greater than the current * capacity of the buffer or less than {@code 0}. */ public void setLength(final 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} if this buffer is empty, that is, its * {@link #length()} is equal to {@code 0}. * @return {@code true} if this buffer is empty, {@code false} * otherwise. */ public boolean isEmpty() { return this.len == 0; } /** * Returns {@code true} if this buffer is full, that is, its * {@link #length()} is equal to its {@link #capacity()}. * @return {@code true} if this buffer is full, {@code false} * 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} and finishing at {@code endIndex}. * If no such character occurs in this buffer within the specified bounds, * {@code -1} is returned. *

* There is no restriction on the value of {@code beginIndex} and * {@code endIndex}. If {@code beginIndex} is negative, * it has the same effect as if it were zero. If {@code endIndex} is * greater than {@link #length()}, it has the same effect as if it were * {@link #length()}. If the {@code beginIndex} is greater than * the {@code endIndex}, {@code -1} is returned. * * @param ch the char to search for. * @param from the index to start the search from. * @param to 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} if the character does * not occur. */ public int indexOf(final int ch, final int from, final int to) { int beginIndex = from; if (beginIndex < 0) { beginIndex = 0; } int endIndex = to; 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} and finishing * at {@link #length()}. If no such character occurs in this buffer within * those bounds, {@code -1} 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} if the character does not occur. */ public int indexOf(final int ch) { return indexOf(ch, 0, this.len); } /** * Returns a substring of this buffer. The substring begins at the specified * {@code beginIndex} and extends to the character at index * {@code endIndex - 1}. * * @param beginIndex the beginning index, inclusive. * @param endIndex the ending index, exclusive. * @return the specified substring. * @throws StringIndexOutOfBoundsException if the * {@code beginIndex} is negative, or * {@code endIndex} is larger than the length of this * buffer, or {@code beginIndex} is larger than * {@code endIndex}. */ public String substring(final int beginIndex, final 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); } 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} and extends to the last * non-whitespace character with the index lesser than * {@code endIndex}. * * @param beginIndex the beginning index, inclusive. * @param endIndex the ending index, exclusive. * @return the specified substring. * @throws IndexOutOfBoundsException if the * {@code beginIndex} is negative, or * {@code endIndex} is larger than the length of this * buffer, or {@code beginIndex} is larger than * {@code endIndex}. */ public String substringTrimmed(final int beginIndex, final 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); } int beginIndex0 = beginIndex; int endIndex0 = endIndex; while (beginIndex0 < endIndex && HTTP.isWhitespace(this.buffer[beginIndex0])) { beginIndex0++; } while (endIndex0 > beginIndex0 && HTTP.isWhitespace(this.buffer[endIndex0 - 1])) { endIndex0--; } return new String(this.buffer, beginIndex0, endIndex0 - beginIndex0); } /** * {@inheritDoc} * @since 4.4 */ @Override public CharSequence subSequence(final int beginIndex, final 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); } return CharBuffer.wrap(this.buffer, beginIndex, endIndex); } @Override public String toString() { return new String(this.buffer, 0, this.len); } }





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