mirror of
https://github.com/servalproject/serval-dna.git
synced 2024-12-21 06:03:12 +00:00
121 lines
2.8 KiB
Java
121 lines
2.8 KiB
Java
/**
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* Copyright (C) 2014 Serval Project Inc.
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*
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* This file is part of Serval Software (http://www.servalproject.org)
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*
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* Serval Software is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this source code; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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package org.servalproject.codec;
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import java.lang.StringBuilder;
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public class Base64 {
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public static final char[] SYMBOLS;
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public static final String charSet="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static{
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char chars[] = new char[64];
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for (int i=0;i<chars.length;i++)
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chars[i]=charSet.charAt(i);
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SYMBOLS=chars;
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};
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public static String encode(byte[] binary)
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{
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StringBuilder sb = new StringBuilder();
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int place = 0;
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byte buf = 0;
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for (byte b: binary) {
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int val = b&0xFF;
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switch (place++) {
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case 0:
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sb.append(SYMBOLS[val >>> 2]);
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buf = (byte)((val << 4) & 0x3f);
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break;
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case 1:
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sb.append(SYMBOLS[(val >>> 4) | buf]);
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buf = (byte)((val << 2) & 0x3f);
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break;
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case 2:
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sb.append(SYMBOLS[(val >>> 6) | buf]);
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sb.append(SYMBOLS[val & 0x3f]);
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place = 0;
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break;
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}
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}
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if (place != 0)
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sb.append(SYMBOLS[buf]);
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switch (place) {
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case 1:
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sb.append('=');
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case 2:
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sb.append('=');
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}
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return sb.toString();
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}
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public static byte[] decode(String value)
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{
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int strlen = value.length();
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if (value.endsWith("=="))
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strlen-=2;
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else if (value.endsWith("="))
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strlen--;
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int len = (strlen+3)/4 * 3;
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switch(strlen%4){
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case 0:
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break;
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case 1:
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case 2:
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len -=2;
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break;
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case 3:
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len --;
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break;
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}
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byte ret[] = new byte[len];
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int pos=0;
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for (int i=0;i<strlen;i++){
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if (value.charAt(i)=='=')
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break;
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int val = charSet.indexOf(value.charAt(i));
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if (val<0)
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return null;
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switch(i%4){
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case 0:
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ret[pos] = (byte) (val<<2);
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break;
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case 1:
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ret[pos++] |= (byte) ((val>>4)&0x03);
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if (pos>=ret.length) break;
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ret[pos] = (byte) (val<<4);
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break;
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case 2:
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ret[pos++] |= (byte) ((val>>2)&0x0F);
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if (pos>=ret.length) break;
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ret[pos] = (byte) (val<<6);
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break;
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case 3:
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ret[pos++] |= (byte) (val & 0x3f);
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break;
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}
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}
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return ret;
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}
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}
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