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The source code/* * Copyright 1999-2004 The Apache Software Foundation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.tomcat.util.buf; import java.io.IOException; /** * Moved from ByteChunk - code to convert from UTF8 bytes to chars. * Not used in the current tomcat3.3 : the performance gain is not very * big if the String is created, only if we avoid that and work only * on char[]. Until than, it's better to be safe. ( I tested this code * with 2 and 3 bytes chars, and it works fine in xerces ) * * Cut from xerces' UTF8Reader.copyMultiByteCharData() * * @author Costin Manolache * @author ( Xml-Xerces ) */ public final class UTF8Decoder extends B2CConverter { // may have state !! public UTF8Decoder() { } public void recycle() { } public void convert(ByteChunk mb, CharChunk cb ) throws IOException { int bytesOff=mb.getOffset(); int bytesLen=mb.getLength(); byte bytes[]=mb.getBytes(); int j=bytesOff; int end=j+bytesLen; while( j< end ) { int b0=0xff & bytes[j]; if( (b0 & 0x80) == 0 ) { cb.append((char)b0); j++; continue; } // 2 byte ? if( j++ >= end ) { // ok, just ignore - we could throw exception throw new IOException( "Conversion error - EOF " ); } int b1=0xff & bytes[j]; // ok, let's the fun begin - we're handling UTF8 if ((0xe0 & b0) == 0xc0) { // 110yyyyy 10xxxxxx (0x80 to 0x7ff) int ch = ((0x1f & b0)<<6) + (0x3f & b1); if(debug>0) log("Convert " + b0 + " " + b1 + " " + ch + ((char)ch)); cb.append((char)ch); j++; continue; } if( j++ >= end ) return ; int b2=0xff & bytes[j]; if( (b0 & 0xf0 ) == 0xe0 ) { if ((b0 == 0xED && b1 >= 0xA0) || (b0 == 0xEF && b1 == 0xBF && b2 >= 0xBE)) { if(debug>0) log("Error " + b0 + " " + b1+ " " + b2 ); throw new IOException( "Conversion error 2"); } int ch = ((0x0f & b0)<<12) + ((0x3f & b1)<<6) + (0x3f & b2); cb.append((char)ch); if(debug>0) log("Convert " + b0 + " " + b1+ " " + b2 + " " + ch + ((char)ch)); j++; continue; } if( j++ >= end ) return ; int b3=0xff & bytes[j]; if (( 0xf8 & b0 ) == 0xf0 ) { if (b0 > 0xF4 || (b0 == 0xF4 && b1 >= 0x90)) { if(debug>0) log("Convert " + b0 + " " + b1+ " " + b2 + " " + b3); throw new IOException( "Conversion error "); } int ch = ((0x0f & b0)<<18) + ((0x3f & b1)<<12) + ((0x3f & b2)<<6) + (0x3f & b3); if(debug>0) log("Convert " + b0 + " " + b1+ " " + b2 + " " + b3 + " " + ch + ((char)ch)); if (ch < 0x10000) { cb.append( (char)ch ); } else { cb.append((char)(((ch-0x00010000)>>10)+ 0xd800)); cb.append((char)(((ch-0x00010000)&0x3ff)+ 0xdc00)); } j++; continue; } else { // XXX Throw conversion exception !!! if(debug>0) log("Convert " + b0 + " " + b1+ " " + b2 + " " + b3); throw new IOException( "Conversion error 4" ); } } } private static int debug=1; void log(String s ) { System.out.println("UTF8Decoder: " + s ); } } |
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