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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;

/**
 * A resizable byte array.
 *
 * @since 4.0
 */
public final class ByteArrayBuffer implements Serializable {

    private static final long serialVersionUID = 4359112959524048036L;

    private byte[] buffer;
    private int len;

    /**
     * Creates an instance of {@link ByteArrayBuffer} with the given initial
     * capacity.
     *
     * @param capacity the capacity
     */
    public ByteArrayBuffer(final int capacity) {
        super();
        Args.notNegative(capacity, "Buffer capacity");
        this.buffer = new byte[capacity];
    }

    private void expand(final int newlen) {
        final byte newbuffer[] = new byte[Math.max(this.buffer.length << 1, newlen)];
        System.arraycopy(this.buffer, 0, newbuffer, 0, this.len);
        this.buffer = newbuffer;
    }

    /**
     * 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.
     *
     * @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} if 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 newlen = this.len + len;
        if (newlen > this.buffer.length) {
            expand(newlen);
        }
        System.arraycopy(b, off, this.buffer, this.len, len);
        this.len = newlen;
    }

    /**
     * Appends {@code b} byte to this buffer. The capacity of the buffer
     * is increased, if necessary, to accommodate the additional byte.
     *
     * @param   b        the byte to be appended.
     */
    public void append(final int b) {
        final int newlen = this.len + 1;
        if (newlen > this.buffer.length) {
            expand(newlen);
        }
        this.buffer[this.len] = (byte)b;
        this.len = newlen;
    }

    /**
     * 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.
     * 

* The chars are converted to bytes using simple cast. * * @param b the chars to be appended. * @param off the index of the first char to append. * @param len the number of bytes to append. * @throws IndexOutOfBoundsException if {@code off} if 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 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++) { final int c = b[i1]; if ((c >= 0x20 && c <= 0x7E) || // Visible ASCII (c >= 0xA0 && c <= 0xFF) || // Visible ISO-8859-1 c == 0x09) { // TAB this.buffer[i2] = (byte) c; } else { this.buffer[i2] = '?'; } } this.len = newlen; } /** * Appends {@code len} chars to this buffer from the given source * char array buffer starting at index {@code off}. The capacity * of the buffer is increased if necessary to accommodate all * {@code len} chars. *

* The chars are converted to bytes using simple cast. * * @param b the chars to be appended. * @param off the index of the first char to append. * @param len the number of bytes to append. * @throws IndexOutOfBoundsException if {@code off} if 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); } /** * Clears content of the buffer. The underlying byte array is not resized. */ public void clear() { this.len = 0; } /** * Converts the content of this buffer to an array of bytes. * * @return byte array */ public byte[] toByteArray() { final byte[] b = new byte[this.len]; if (this.len > 0) { System.arraycopy(this.buffer, 0, b, 0, this.len); } return b; } /** * Returns the {@code byte} 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 byte value. * @return the byte value at the specified index. * @throws IndexOutOfBoundsException if {@code index} is * negative or greater than or equal to {@link #length()}. */ public int byteAt(final int i) { return this.buffer[i]; } /** * Returns the current capacity. The capacity is the amount of storage * available for newly appended bytes, beyond which an allocation * will occur. * * @return the current capacity */ public int capacity() { return this.buffer.length; } /** * Returns the length of the buffer (byte 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} * argument is non-positive, this method takes no action. * * @param required the minimum required capacity. * * @since 4.1 */ 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); } } /** * Returns reference to the underlying byte array. * * @return the byte array. */ public byte[] buffer() { return this.buffer; } /** * 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 byte, starting the search at the specified * {@code beginIndex} and finishing at {@code endIndex}. * If no such byte 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 b the byte 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 byte in the buffer * within the given bounds, or {@code -1} if the byte does * not occur. * * @since 4.1 */ public int indexOf(final byte b, 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] == b) { return i; } } return -1; } /** * Returns the index within this buffer of the first occurrence of the * specified byte, starting the search at {@code 0} and finishing * at {@link #length()}. If no such byte occurs in this buffer within * those bounds, {@code -1} is returned. * * @param b the byte to search for. * @return the index of the first occurrence of the byte in the * buffer, or {@code -1} if the byte does not occur. * * @since 4.1 */ public int indexOf(final byte b) { return indexOf(b, 0, this.len); } }





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