bytearraybuffer.java

又一个课程设计 简易 JSP 论坛 功能较简单的那种, 界面上模仿了 Discuz JSP 本来就学的不行, 只是尽量实现了 MVC

package cn.ialvin.web.upload;

import java.util.Arrays;
import java.util.LinkedList;

public class ByteArrayBuffer {
	public static void main(String[] a) {
		ByteArrayBuffer array = new ByteArrayBuffer(0);
		array.append(new byte[] { 1, 2, 3, 4, 5 });
		array.append(new byte[] { 11, 13, 25 });
		System.out.println(Arrays.toString(array.subArray(0, array.length)));

		array.set(0, (byte) 18);
		System.out.println(Arrays.toString(array.subArray(0, array.length)));

		byte[] bbs = array.shift(2);
		System.out.println(array.length());
		bbs = array.shift(4);
		System.out.println(Arrays.toString(bbs));
		System.out.println(array.length());
		System.out.println(Arrays.toString(array.subArray(0, array.length())));
		array.shift(array.length());
		System.out.println(Arrays.toString(array.subArray(0, array.length())));
	}

	private void _shift(int l) {
		while (l > this.blockSize) {
			l -= this.blockSize;
			this.queue.removeFirst();
			this.blockNum--;
		}
		this.blankH = l;
	}

	public byte[] shift(int l) {
		synchronized (this.lock) {
			if (l < 0 || l > this.length)
				throw new ArrayIndexOutOfBoundsException();
			byte[] res = new byte[l];
			for (int i = 0; i < l; i++) {
				res[i] = this._get(i);
			}
			this.length -= l;
			l += this.blankH;
			this._shift(l);
			return res;
		}
	}

	private LinkedList<byte[]> queue = new LinkedList<byte[]>();

	private int blockSize = 1024;

	private int length = 0;

	private int blockNum = 0;

	private int blankR = 0;

	private int blankH = 0;

	private Object lock = new Object();

	public ByteArrayBuffer(int blockSize) {
		if (blockSize > 0)
			this.blockSize = blockSize;
		this.appendBlock();
	}

	private byte[] appendBlock() {
		byte[] bits = new byte[this.blockSize];
		this.queue.add(bits);
		this.blockNum++;
		this.blankR = this.blockSize;
		return bits;
	}

	public void append(byte[] arr, int len) {
		synchronized (this.lock) {
			byte[] rear = this.queue.getLast();
			for (int i = 0; i < len; i++) {
				if (this.blankR == 0)
					rear = this.appendBlock();
				rear[blockSize - this.blankR] = arr[i];
				this.blankR--;
				this.length++;
			}
		}
	}

	private byte _get(int i) {
		i += this.blankH;
		return this.queue.get(i / this.blockSize)[i % this.blockSize];
	}

	public byte get(int i) {
		synchronized (this.lock) {
			if (i < 0 || i >= this.length)
				throw new ArrayIndexOutOfBoundsException();
			return this._get(i);
		}
	}

	public boolean set(int i, byte b) {
		synchronized (this.lock) {
			if (i < 0 || i >= this.length)
				throw new ArrayIndexOutOfBoundsException();
			i += this.blankH;
			this.queue.get(i / this.blockSize)[i % this.blockSize] = b;
			return true;
		}
	}

	public int indexOf(byte[] b) {
		return this.indexOf(b, 0);
	}

	public int indexOf(byte[] b, int pos) {
		if (b.length < 1)
			return -1;
		if (pos < 0) pos = 0;
		if (b.length + pos > this.length)
			return -1;
		int sKey = 0;
		synchronized (this.lock) {
			int v;
			while (this.length > pos) {
				v = this._get(pos);
				if (v == b[sKey]) {
					sKey++;
					if (sKey == b.length)
						return pos - sKey + 1;
				} else if (v == b[0]) {
					sKey = 1;
				} else {
					sKey = 0;
				}
				pos++;
			}
			return -1;
		}
	}

	public void each(ByteEnumerator be, int offset, int len) {
		synchronized (this.lock) {
			if (offset + len > this.length || len < 0)
				throw new ArrayIndexOutOfBoundsException();
			for (int i = 0; i < len; i++, offset++)
				be.forEach(this._get(offset));
		}
	}
	
	public byte[] subArray(int offset, int len) {
		synchronized (this.lock) {
			if (offset + len > this.length || len < 0)
				throw new ArrayIndexOutOfBoundsException();
			byte[] bits = new byte[len];
			for (int i = 0; i < len; i++, offset++)
				bits[i] = this._get(offset);
			return bits;
		}
	}

	public int length() {
		return this.length;
	}

	public void append(byte[] arr) {
		this.append(arr, arr.length);
	}

	public void append(byte b) {
		byte[] bs = new byte[1];
		bs[0] = b;
		this.append(bs);
	}
}