161 lines
4.3 KiB
Java
161 lines
4.3 KiB
Java
/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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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 org.apache.poi.util;
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import java.io.FilterInputStream;
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import java.io.IOException;
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import java.io.InputStream;
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/**
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* Wraps an {@link InputStream} providing {@link LittleEndianInput}<p/>
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*
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* This class does not buffer any input, so the stream read position maintained
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* by this class is consistent with that of the inner stream.
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*/
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public class LittleEndianInputStream extends FilterInputStream implements LittleEndianInput {
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private static final int EOF = -1;
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public LittleEndianInputStream(InputStream is) {
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super(is);
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}
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@Override
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@SuppressForbidden("just delegating")
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public int available() {
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try {
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return super.available();
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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}
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@Override
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public byte readByte() {
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return (byte)readUByte();
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}
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@Override
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public int readUByte() {
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byte buf[] = new byte[1];
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try {
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checkEOF(read(buf), 1);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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return LittleEndian.getUByte(buf);
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}
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@Override
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public double readDouble() {
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return Double.longBitsToDouble(readLong());
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}
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@Override
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public int readInt() {
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byte buf[] = new byte[LittleEndianConsts.INT_SIZE];
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try {
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checkEOF(read(buf), buf.length);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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return LittleEndian.getInt(buf);
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}
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/**
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* get an unsigned int value from an InputStream
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*
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* @return the unsigned int (32-bit) value
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* @exception RuntimeException
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* wraps any IOException thrown from reading the stream.
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*/
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//@Override
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public long readUInt() {
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long retNum = readInt();
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return retNum & 0x00FFFFFFFFL;
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}
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@Override
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public long readLong() {
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byte buf[] = new byte[LittleEndianConsts.LONG_SIZE];
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try {
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checkEOF(read(buf), LittleEndianConsts.LONG_SIZE);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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return LittleEndian.getLong(buf);
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}
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@Override
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public short readShort() {
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return (short)readUShort();
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}
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@Override
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public int readUShort() {
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byte buf[] = new byte[LittleEndianConsts.SHORT_SIZE];
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try {
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checkEOF(read(buf), LittleEndianConsts.SHORT_SIZE);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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return LittleEndian.getUShort(buf);
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}
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private static void checkEOF(int actualBytes, int expectedBytes) {
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if (expectedBytes != 0 && (actualBytes == -1 || actualBytes != expectedBytes)) {
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throw new RuntimeException("Unexpected end-of-file");
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}
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}
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@Override
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public void readFully(byte[] buf) {
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readFully(buf, 0, buf.length);
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}
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@Override
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public void readFully(byte[] buf, int off, int len) {
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try {
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checkEOF(_read(buf, off, len), len);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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}
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//Makes repeated calls to super.read() until length is read or EOF is reached
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private int _read(byte[] buffer, int offset, int length) throws IOException {
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//lifted directly from org.apache.commons.io.IOUtils 2.4
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int remaining = length;
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while (remaining > 0) {
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int location = length - remaining;
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int count = read(buffer, offset + location, remaining);
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if (EOF == count) { // EOF
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break;
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}
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remaining -= count;
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}
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return length - remaining;
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}
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@Override
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public void readPlain(byte[] buf, int off, int len) {
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readFully(buf, off, len);
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}
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}
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