mirror of
https://github.com/alibaba/druid.git
synced 2023-03-04 19:17:16 +00:00
113 lines
3.5 KiB
Java
113 lines
3.5 KiB
Java
/*
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* Copyright 1999-2002,2004 The Apache Software Foundation.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.alibaba.druid.util;
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/**
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* format validation
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*
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* This class encodes/decodes hexadecimal data
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*
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* @xerces.internal
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*
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* @author Jeffrey Rodriguez
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* @version $Id: HexBin.java,v 1.4 2007/07/19 04:38:32 ofung Exp $
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*/
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public final class HexBin {
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static private final int BASELENGTH = 128;
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static private final int LOOKUPLENGTH = 16;
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static final private byte [] hexNumberTable = new byte[BASELENGTH];
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static final private char [] lookUpHexAlphabet = new char[LOOKUPLENGTH];
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static {
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for (int i = 0; i < BASELENGTH; i++ ) {
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hexNumberTable[i] = -1;
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}
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for ( int i = '9'; i >= '0'; i--) {
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hexNumberTable[i] = (byte) (i-'0');
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}
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for ( int i = 'F'; i>= 'A'; i--) {
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hexNumberTable[i] = (byte) ( i-'A' + 10 );
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}
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for ( int i = 'f'; i>= 'a'; i--) {
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hexNumberTable[i] = (byte) ( i-'a' + 10 );
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}
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for(int i = 0; i<10; i++ ) {
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lookUpHexAlphabet[i] = (char)('0'+i);
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}
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for(int i = 10; i<=15; i++ ) {
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lookUpHexAlphabet[i] = (char)('A'+i -10);
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}
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}
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/**
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* Encode a byte array to hex string
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*
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* @param binaryData array of byte to encode
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* @return return encoded string
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*/
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static public String encode(byte[] binaryData) {
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if (binaryData == null)
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return null;
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int lengthData = binaryData.length;
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int lengthEncode = lengthData * 2;
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char[] encodedData = new char[lengthEncode];
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int temp;
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for (int i = 0; i < lengthData; i++) {
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temp = binaryData[i];
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if (temp < 0)
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temp += 256;
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encodedData[i*2] = lookUpHexAlphabet[temp >> 4];
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encodedData[i*2+1] = lookUpHexAlphabet[temp & 0xf];
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}
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return new String(encodedData);
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}
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/**
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* Decode hex string to a byte array
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*
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* @param encoded encoded string
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* @return return array of byte to encode
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*/
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static public byte[] decode(String encoded) {
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if (encoded == null)
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return null;
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int lengthData = encoded.length();
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if (lengthData % 2 != 0)
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return null;
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char[] binaryData = encoded.toCharArray();
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int lengthDecode = lengthData / 2;
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byte[] decodedData = new byte[lengthDecode];
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byte temp1, temp2;
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char tempChar;
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for( int i = 0; i<lengthDecode; i++ ){
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tempChar = binaryData[i*2];
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temp1 = (tempChar < BASELENGTH) ? hexNumberTable[tempChar] : -1;
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if (temp1 == -1)
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return null;
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tempChar = binaryData[i*2+1];
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temp2 = (tempChar < BASELENGTH) ? hexNumberTable[tempChar] : -1;
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if (temp2 == -1)
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return null;
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decodedData[i] = (byte)((temp1 << 4) | temp2);
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}
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return decodedData;
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}
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}
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