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Apache POI - Java API To Access Microsoft Format Files
/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.poi.hssf.record.cont;
import org.apache.poi.hssf.record.RecordInputStream;
import org.apache.poi.hssf.record.ContinueRecord;
import org.apache.poi.util.LittleEndianInput;
/**
* A decorated {@link RecordInputStream} that can read primitive data types
* (short, int, long, etc.) spanned across a {@link ContinueRecord } boundary.
*
*
* Most records construct themselves from {@link RecordInputStream}.
* This class assumes that a {@link ContinueRecord} record break always occurs at the type boundary,
* however, it is not always so.
*
* Two attachments to Bugzilla 50779
* demonstrate that a CONTINUE break can appear right in between two bytes of a unicode character
* or between two bytes of a short
. The problematic portion of the data is
* in a Asian Phonetic Settings Block (ExtRst) of a UnicodeString.
*
* {@link RecordInputStream} greedily requests the bytes to be read and stumbles on such files with a
* "Not enough data (1) to read requested (2) bytes" exception. The ContinuableRecordInput
* class circumvents this "type boundary" rule and reads data byte-by-byte rolling over CONTINUE if necessary.
*
*
*
* YK: For now (March 2011) this class is only used to read
* @see org.apache.poi.hssf.record.common.UnicodeString.ExtRst blocks of a UnicodeString.
*
*
*/
public class ContinuableRecordInput implements LittleEndianInput {
private final RecordInputStream _in;
public ContinuableRecordInput(RecordInputStream in){
_in = in;
}
@Override
public int available(){
return _in.available();
}
@Override
public byte readByte(){
return _in.readByte();
}
@Override
public int readUByte(){
return _in.readUByte();
}
@Override
public short readShort(){
return _in.readShort();
}
@Override
public int readUShort(){
int ch1 = readUByte();
int ch2 = readUByte();
return (ch2 << 8) + (ch1 << 0);
}
@Override
public int readInt(){
int ch1 = _in.readUByte();
int ch2 = _in.readUByte();
int ch3 = _in.readUByte();
int ch4 = _in.readUByte();
return (ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0);
}
@Override
public long readLong(){
int b0 = _in.readUByte();
int b1 = _in.readUByte();
int b2 = _in.readUByte();
int b3 = _in.readUByte();
int b4 = _in.readUByte();
int b5 = _in.readUByte();
int b6 = _in.readUByte();
int b7 = _in.readUByte();
return (((long)b7 << 56) +
((long)b6 << 48) +
((long)b5 << 40) +
((long)b4 << 32) +
((long)b3 << 24) +
(b2 << 16) +
(b1 << 8) +
(b0 << 0));
}
@Override
public double readDouble(){
return _in.readDouble();
}
@Override
public void readFully(byte[] buf){
_in.readFully(buf);
}
@Override
public void readFully(byte[] buf, int off, int len){
_in.readFully(buf, off, len);
}
@Override
public void readPlain(byte[] buf, int off, int len) {
readFully(buf, off, len);
}
}