charutil.java

来自「这是一个轻便的j2ee的web应用框架,是一个在多个项目中运用的实际框架,采用s」· Java 代码 · 共 51 行

/*
 * Created on 2004-5-11
 *
 */
package com.esimple.service.crypto.util;

/**
 * @author steven
 *
 */
public class CharUtil {
	public static int convertUnsignedByteToInt(byte b) {
		if (b >= 0)
			return b;
		else
			return 256 + b;
	}
	
	public static int mapCharToInt(char c) {
		if (c >= 'A' && c <= 'Z')
			return c - 65;
		if (c >= 'a' && c <= 'z')
			return (c - 97) + 26;
		if (c >= '0' && c <= '9')
			return (c - 48) + 52;
		if (c == '+')
			return 62;
		if (c == '/')
			return 63;
		else
			throw new IllegalArgumentException(
				c + " is not a valid Base64 character.");
	}
	
	public static char mapByteToChar(byte b) {
		if (b < 26)
			return (char) (65 + b);
		if (b < 52)
			return (char) (97 + (b - 26));
		if (b < 62)
			return (char) (48 + (b - 52));
		if (b == 62)
			return '+';
		if (b == 63)
			return '/';
		else
			throw new IllegalArgumentException(
				"Byte " + new Integer(b) + " is not a valid Base64 value");
	}
}