ioutils.java

java的共享内存管理.基于MMF设计。封装了java.nio.MappedByteBuffer.在大流量实时业务系统时

/*
 * @(#)IOUtils.java	1.00 2007-12-7
 *
 * Copyright 2007 BCINFO. All Rights Reserved.
 * 
 * Programmer: Xuym.
 */
package com.bci.commons.util;

/**
 * IO操作类 主要用于字节和数字的转换
 * 
 * @author xuym
 * @version 1.00, 2007-12-7
 * @since 1.5
 */

public class IOUtils {

	public IOUtils() {
	}

	public static final int byte2int(byte b[], int offset) {
		return b[offset + 3] & 0xff | (b[offset + 2] & 0xff) << 8
				| (b[offset + 1] & 0xff) << 16 | (b[offset] & 0xff) << 24;
	}

	public static final int byte2int(byte b[]) {
		return b[3] & 0xff | (b[2] & 0xff) << 8 | (b[1] & 0xff) << 16
				| (b[0] & 0xff) << 24;
	}

	public static final long byte2long(byte b[]) {
		return (long) b[7] & (long) 255 | ((long) b[6] & (long) 255) << 8
				| ((long) b[5] & (long) 255) << 16
				| ((long) b[4] & (long) 255) << 24
				| ((long) b[3] & (long) 255) << 32
				| ((long) b[2] & (long) 255) << 40
				| ((long) b[1] & (long) 255) << 48 | (long) b[0] << 56;
	}

	public static final long byte2long(byte b[], int offset) {
		return (long) b[offset + 7] & (long) 255
				| ((long) b[offset + 6] & (long) 255) << 8
				| ((long) b[offset + 5] & (long) 255) << 16
				| ((long) b[offset + 4] & (long) 255) << 24
				| ((long) b[offset + 3] & (long) 255) << 32
				| ((long) b[offset + 2] & (long) 255) << 40
				| ((long) b[offset + 1] & (long) 255) << 48
				| (long) b[offset] << 56;
	}

	public static final byte[] int2byte(int n) {
		byte b[] = new byte[4];
		b[0] = (byte) (n >> 24);
		b[1] = (byte) (n >> 16);
		b[2] = (byte) (n >> 8);
		b[3] = (byte) n;
		return b;
	}

	public static final void int2byte(int n, byte buf[], int offset) {
		buf[offset] = (byte) (n >> 24);
		buf[offset + 1] = (byte) (n >> 16);
		buf[offset + 2] = (byte) (n >> 8);
		buf[offset + 3] = (byte) n;
	}

	public static final byte[] short2byte(int n) {
		byte b[] = new byte[2];
		b[0] = (byte) (n >> 8);
		b[1] = (byte) n;
		return b;
	}

	public static final void short2byte(int n, byte buf[], int offset) {
		buf[offset] = (byte) (n >> 8);
		buf[offset + 1] = (byte) n;
	}

	public static final byte[] long2byte(long n) {
		byte b[] = new byte[8];
		b[0] = (byte) (int) (n >> 56);
		b[1] = (byte) (int) (n >> 48);
		b[2] = (byte) (int) (n >> 40);
		b[3] = (byte) (int) (n >> 32);
		b[4] = (byte) (int) (n >> 24);
		b[5] = (byte) (int) (n >> 16);
		b[6] = (byte) (int) (n >> 8);
		b[7] = (byte) (int) n;
		return b;
	}

	public static final void long2byte(long n, byte buf[], int offset) {
		buf[offset] = (byte) (int) (n >> 56);
		buf[offset + 1] = (byte) (int) (n >> 48);
		buf[offset + 2] = (byte) (int) (n >> 40);
		buf[offset + 3] = (byte) (int) (n >> 32);
		buf[offset + 4] = (byte) (int) (n >> 24);
		buf[offset + 5] = (byte) (int) (n >> 16);
		buf[offset + 6] = (byte) (int) (n >> 8);
		buf[offset + 7] = (byte) (int) n;
	}

	public static final long getLong(byte[] b, int off) {
		return ((b[off + 7] & 0xFFL) << 0) + ((b[off + 6] & 0xFFL) << 8)
				+ ((b[off + 5] & 0xFFL) << 16) + ((b[off + 4] & 0xFFL) << 24)
				+ ((b[off + 3] & 0xFFL) << 32) + ((b[off + 2] & 0xFFL) << 40)
				+ ((b[off + 1] & 0xFFL) << 48) + ((b[off + 0] & 0xFFL) << 56);
	}

	public static final String readString(byte[] b, int offset, int len) {
		try {
			if (len > 0)
				return (new String(b, offset, len, "US-ASCII"));
			else
				return ("");
		} catch (java.io.UnsupportedEncodingException x) {
			return ("");
		}
	}

	/**
	 * Convert an integer to a byte array in MSB first order
	 * 
	 * @param num
	 *            The number to store
	 * @param len
	 *            The length of the integer to convert
	 * @return An array of length len containing the byte representation of num.
	 */
	public static final byte[] intToBytes(int num, int len) {
		return (intToBytes(num, len, null, 0));
	}

	/**
	 * Convert an integer to a byte array in MSB first order. This method exists
	 * as well as the <code>longToBytes</code> method for performance reasons.
	 * More often than not, a 4-byte value is the largest being
	 * converted...doing that using <code>ints</code> instead of
	 * <code>longs</code> will offer a slight performance increase. The code
	 * for the two methods is identical except for using ints instead of longs
	 * to hold mask, shiftwidth and number values.
	 * 
	 * @param num
	 *            The number to store
	 * @param len
	 *            The length of the integer to convert (that is, the number of
	 *            bytes to generate).
	 * @param b
	 *            the byte array to write the integer to.
	 * @param offset
	 *            the offset in <code>b</code> to write the integer to.
	 * @return An array of length len containing the byte representation of num.
	 */
	public static final byte[] intToBytes(int num, int len, byte[] b, int offset) {

		if (b == null) {
			b = new byte[len];
			offset = 0;
		}
		int sw = ((len - 1) * 8);
		int mask = (0xff << sw);

		for (int l = 0; l < len; l++) {
			b[offset + l] = (byte) ((num & mask) >>> sw);

			sw -= 8;
			mask >>>= 8;
		}

		return (b);
	}

	/**
	 * Convert a long to a byte array in MSB first order.
	 * 
	 * @param num
	 *            The number to store
	 * @param len
	 *            The length of the integer to convert (that is, the number of
	 *            bytes to generate).
	 * @return An array of length len containing the byte representation of num.
	 */
	public static final byte[] longToBytes(long num, int len) {
		return (longToBytes(num, len, null, 0));
	}

	/**
	 * Convert a long to a byte array in MSB first order.
	 * 
	 * @param num
	 *            The number to store
	 * @param len
	 *            The length of the integer to convert (that is, the number of
	 *            bytes to generate).
	 * @param b
	 *            the byte array to write the integer to.
	 * @param offset
	 *            the offset in <code>b</code> to write the integer to.
	 * @return An array of length len containing the byte representation of num.
	 */
	public static final byte[] longToBytes(long num, int len, byte[] b,
			int offset) {

		if (b == null) {
			b = new byte[len];
			offset = 0;
		}
		long sw = ((len - 1) * 8);
		long mask = (0xffL << sw);

		for (int l = 0; l < len; l++) {
			b[offset + l] = (byte) ((num & mask) >>> sw);

			sw -= 8;
			mask >>>= 8;
		}

		return (b);
	}

	/**
	 * Convert a byte array (or part thereof) into an integer. The byte array
	 * should be in big-endian form. That is, the byte at index 'offset' should
	 * be the MSB.
	 * 
	 * @param b
	 *            The array containing the bytes
	 * @param offset
	 *            The array index of the MSB
	 * @param size
	 *            The number of bytes to convert into the integer
	 * @return An integer value represented by the specified bytes.
	 */
	public static final int bytesToInt(byte[] b, int offset, int size) {
		int num = 0;
		int sw = 8 * (size - 1);

		for (int loop = 0; loop < size; loop++) {
			num |= ((int) b[offset + loop] & 0x00ff) << sw;
			sw -= 8;
		}

		return (num);
	}

	/**
	 * Convert a byte array (or part thereof) into a long. The byte array should
	 * be in big-endian form. That is, the byte at index 'offset' should be the
	 * MSB.
	 * 
	 * @param b
	 *            The array containing the bytes
	 * @param offset
	 *            The array index of the MSB
	 * @param size
	 *            The number of bytes to convert into the long
	 * @return An long value represented by the specified bytes.
	 */
	public static final long bytesToLong(byte[] b, int offset, int size) {
		long num = 0;
		long sw = 8L * ((long) size - 1L);

		for (int loop = 0; loop < size; loop++) {
			num |= ((long) b[offset + loop] & 0x00ff) << sw;
			sw -= 8;
		}

		return (num);
	}

	public static void main(String[] arg) {

		/*
		 * DecimalFormat df = new DecimalFormat("0000000");
		 * System.out.println(df.format(123)); MessageFormat mf = new
		 * MessageFormat("yyyy-MM-dd");
		 * System.out.println(mf.format("2006-07-11"));
		 */
		int i = 132;
		byte b = IOUtils.int2byte(i)[3];
		int k = IOUtils.bytesToInt(new byte[] { b }, 0, 1);
		System.out.println(b);
		System.out.println(k);
	}

	public static String encodeHex(byte[] bytes) {
		if (bytes == null)
			return "";
		StringBuffer buf = new StringBuffer(bytes.length * 2);
		for (int i = 0; i < bytes.length; i++) {
			if (((int) bytes[i] & 0xff) < 0x10) {
				buf.append("0");
			}
			buf.append(Long.toString((int) bytes[i] & 0xff, 16));
		}
		return buf.toString();
	}

	public static byte[] hexToBytes(String ss) {
		byte[] bytes = new byte[ss.length() / 2];
		char[] chars = ss.toLowerCase().toCharArray();
		int byteCount = 0;
		for (int i = 0; i < chars.length; i += 2) {
			byte newByte = 0x00;
			newByte |= hexCharToByte(chars[i]);
			newByte <<= 4;
			newByte |= hexCharToByte(chars[i + 1]);
			bytes[byteCount] = newByte;
			byteCount++;
		}
		return bytes;
	}

	private static byte hexCharToByte(char ch) {
		switch (ch) {
		case '0':
			return 0x00;
		case '1':
			return 0x01;
		case '2':
			return 0x02;
		case '3':
			return 0x03;
		case '4':
			return 0x04;
		case '5':
			return 0x05;
		case '6':
			return 0x06;
		case '7':
			return 0x07;
		case '8':
			return 0x08;
		case '9':
			return 0x09;
		case 'a':
			return 0x0A;
		case 'b':
			return 0x0B;
		case 'c':
			return 0x0C;
		case 'd':
			return 0x0D;
		case 'e':
			return 0x0E;
		case 'f':
			return 0x0F;
		}
		return 0x00;
	}
}