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- /* ====================================================================
- 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.poifs.filesystem;
-
- import java.io.IOException;
-
- import org.apache.poi.poifs.storage.DataInputBlock;
- import org.apache.poi.util.RecordFormatException;
-
- /**
- * This class provides methods to read a DocumentEntry managed by a
- * {@link OPOIFSFileSystem} instance.
- */
- public final class ODocumentInputStream extends DocumentInputStream {
- /** current offset into the Document */
- private int _current_offset;
-
- /** current marked offset into the Document (used by mark and reset) */
- private int _marked_offset;
-
- /** the Document's size */
- private final int _document_size;
-
- /** have we been closed? */
- private boolean _closed;
-
- /** the actual Document */
- private final OPOIFSDocument _document;
-
- /** the data block containing the current stream pointer */
- private DataInputBlock _currentBlock;
-
- /**
- * Create an InputStream from the specified DocumentEntry
- *
- * @param document the DocumentEntry to be read
- *
- * @exception IOException if the DocumentEntry cannot be opened (like, maybe it has
- * been deleted?)
- */
- public ODocumentInputStream(DocumentEntry document) throws IOException {
- if (!(document instanceof DocumentNode)) {
- throw new IOException("Cannot open internal document storage");
- }
- DocumentNode documentNode = (DocumentNode)document;
- if (documentNode.getDocument() == null) {
- throw new IOException("Cannot open internal document storage");
- }
-
- _current_offset = 0;
- _marked_offset = 0;
- _document_size = document.getSize();
- if (_document_size < 0) {
- throw new RecordFormatException("document_size cannot be < 0");
- }
- _closed = false;
- _document = documentNode.getDocument();
- _currentBlock = getDataInputBlock(0);
- }
-
- /**
- * Create an InputStream from the specified Document
- *
- * @param document the Document to be read
- */
- public ODocumentInputStream(OPOIFSDocument document) {
- _current_offset = 0;
- _marked_offset = 0;
- _document_size = document.getSize();
- _closed = false;
- _document = document;
- _currentBlock = getDataInputBlock(0);
- }
-
- @Override
- public int available() {
- if (_closed) {
- throw new IllegalStateException("cannot perform requested operation on a closed stream");
- }
- return _document_size - _current_offset;
- }
-
- @Override
- public void close() {
- _closed = true;
- }
-
- @Override
- public void mark(int ignoredReadlimit) {
- _marked_offset = _current_offset;
- }
-
- private DataInputBlock getDataInputBlock(int offset) {
- return _document.getDataInputBlock(offset);
- }
-
- @Override
- public int read() throws IOException {
- dieIfClosed();
- if (atEOD()) {
- return EOF;
- }
- int result = _currentBlock.readUByte();
- _current_offset++;
- if (_currentBlock.available() < 1) {
- _currentBlock = getDataInputBlock(_current_offset);
- }
- return result;
- }
-
- @Override
- public int read(byte[] b, int off, int len) throws IOException {
- dieIfClosed();
- if (b == null) {
- throw new IllegalArgumentException("buffer must not be null");
- }
- if (off < 0 || len < 0 || b.length < off + len) {
- throw new IndexOutOfBoundsException("can't read past buffer boundaries");
- }
- if (len == 0) {
- return 0;
- }
- if (atEOD()) {
- return EOF;
- }
- int limit = Math.min(available(), len);
- readFully(b, off, limit);
- return limit;
- }
-
- /**
- * Repositions this stream to the position at the time the mark() method was
- * last called on this input stream. If mark() has not been called this
- * method repositions the stream to its beginning.
- */
- @Override
- public void reset() {
- _current_offset = _marked_offset;
- _currentBlock = getDataInputBlock(_current_offset);
- }
-
- @Override
- public long skip(long n) throws IOException {
- dieIfClosed();
- if (n < 0) {
- return 0;
- }
- int new_offset = _current_offset + (int) n;
-
- if (new_offset < _current_offset) {
-
- // wrap around in converting a VERY large long to an int
- new_offset = _document_size;
- } else if (new_offset > _document_size) {
- new_offset = _document_size;
- }
- long rval = new_offset - _current_offset;
-
- _current_offset = new_offset;
- _currentBlock = getDataInputBlock(_current_offset);
- return rval;
- }
-
- private void dieIfClosed() throws IOException {
- if (_closed) {
- throw new IOException("cannot perform requested operation on a closed stream");
- }
- }
-
- private boolean atEOD() {
- return _current_offset == _document_size;
- }
-
- private void checkAvaliable(int requestedSize) {
- if (_closed) {
- throw new IllegalStateException("cannot perform requested operation on a closed stream");
- }
- if (requestedSize > _document_size - _current_offset) {
- throw new RuntimeException("Buffer underrun - requested " + requestedSize
- + " bytes but " + (_document_size - _current_offset) + " was available");
- }
- }
-
- @Override
- public byte readByte() {
- return (byte) readUByte();
- }
-
- @Override
- public double readDouble() {
- return Double.longBitsToDouble(readLong());
- }
-
- @Override
- public short readShort() {
- return (short) readUShort();
- }
-
- @Override
- public void readFully(byte[] buf, int off, int len) {
- checkAvaliable(len);
- int blockAvailable = _currentBlock.available();
- if (blockAvailable > len) {
- _currentBlock.readFully(buf, off, len);
- _current_offset += len;
- return;
- }
- // else read big amount in chunks
- int remaining = len;
- int writePos = off;
- while (remaining > 0) {
- boolean blockIsExpiring = remaining >= blockAvailable;
- int reqSize;
- if (blockIsExpiring) {
- reqSize = blockAvailable;
- } else {
- reqSize = remaining;
- }
- _currentBlock.readFully(buf, writePos, reqSize);
- remaining -= reqSize;
- writePos += reqSize;
- _current_offset += reqSize;
- if (blockIsExpiring) {
- if (_current_offset == _document_size) {
- if (remaining > 0) {
- throw new IllegalStateException(
- "reached end of document stream unexpectedly");
- }
- _currentBlock = null;
- break;
- }
- _currentBlock = getDataInputBlock(_current_offset);
- blockAvailable = _currentBlock.available();
- }
- }
- }
-
- @Override
- public long readLong() {
- checkAvaliable(SIZE_LONG);
- int blockAvailable = _currentBlock.available();
- long result;
- if (blockAvailable > SIZE_LONG) {
- result = _currentBlock.readLongLE();
- } else {
- DataInputBlock nextBlock = getDataInputBlock(_current_offset + blockAvailable);
- if (blockAvailable == SIZE_LONG) {
- result = _currentBlock.readLongLE();
- } else {
- result = nextBlock.readLongLE(_currentBlock, blockAvailable);
- }
- _currentBlock = nextBlock;
- }
- _current_offset += SIZE_LONG;
- return result;
- }
-
- @Override
- public int readInt() {
- checkAvaliable(SIZE_INT);
- int blockAvailable = _currentBlock.available();
- int result;
- if (blockAvailable > SIZE_INT) {
- result = _currentBlock.readIntLE();
- } else {
- DataInputBlock nextBlock = getDataInputBlock(_current_offset + blockAvailable);
- if (blockAvailable == SIZE_INT) {
- result = _currentBlock.readIntLE();
- } else {
- result = nextBlock.readIntLE(_currentBlock, blockAvailable);
- }
- _currentBlock = nextBlock;
- }
- _current_offset += SIZE_INT;
- return result;
- }
-
- @Override
- public int readUShort() {
- checkAvaliable(SIZE_SHORT);
- int blockAvailable = _currentBlock.available();
- int result;
- if (blockAvailable > SIZE_SHORT) {
- result = _currentBlock.readUShortLE();
- } else {
- DataInputBlock nextBlock = getDataInputBlock(_current_offset + blockAvailable);
- if (blockAvailable == SIZE_SHORT) {
- result = _currentBlock.readUShortLE();
- } else {
- result = nextBlock.readUShortLE(_currentBlock);
- }
- _currentBlock = nextBlock;
- }
- _current_offset += SIZE_SHORT;
- return result;
- }
-
- @Override
- public int readUByte() {
- checkAvaliable(1);
- int result = _currentBlock.readUByte();
- _current_offset++;
- if (_currentBlock.available() < 1) {
- _currentBlock = getDataInputBlock(_current_offset);
- }
- return result;
- }
- }
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