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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.util;
-
- import java.io.ByteArrayOutputStream;
- import java.io.Closeable;
- import java.io.File;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.OutputStream;
- import java.io.PushbackInputStream;
- import java.nio.ByteBuffer;
- import java.nio.channels.ReadableByteChannel;
- import java.util.zip.CRC32;
- import java.util.zip.Checksum;
-
- import org.apache.poi.EmptyFileException;
- import org.apache.poi.POIDocument;
- import org.apache.poi.ss.usermodel.Workbook;
-
- public final class IOUtils {
- private static final POILogger logger = POILogFactory.getLogger( IOUtils.class );
-
- private IOUtils() {
- // no instances of this class
- }
-
- /**
- * Peeks at the first 8 bytes of the stream. Returns those bytes, but
- * with the stream unaffected. Requires a stream that supports mark/reset,
- * or a PushbackInputStream. If the stream has >0 but <8 bytes,
- * remaining bytes will be zero.
- * @throws EmptyFileException if the stream is empty
- */
- public static byte[] peekFirst8Bytes(InputStream stream) throws IOException, EmptyFileException {
- return peekFirstNBytes(stream, 8);
- }
-
- /**
- * Peeks at the first N bytes of the stream. Returns those bytes, but
- * with the stream unaffected. Requires a stream that supports mark/reset,
- * or a PushbackInputStream. If the stream has >0 but <N bytes,
- * remaining bytes will be zero.
- * @throws EmptyFileException if the stream is empty
- */
- public static byte[] peekFirstNBytes(InputStream stream, int limit) throws IOException, EmptyFileException {
- stream.mark(limit);
- ByteArrayOutputStream bos = new ByteArrayOutputStream(limit);
- copy(new BoundedInputStream(stream, limit), bos);
-
- int readBytes = bos.size();
- if (readBytes == 0) {
- throw new EmptyFileException();
- }
-
- if (readBytes < limit) {
- bos.write(new byte[limit-readBytes]);
- }
- byte peekedBytes[] = bos.toByteArray();
- if(stream instanceof PushbackInputStream) {
- PushbackInputStream pin = (PushbackInputStream)stream;
- pin.unread(peekedBytes, 0, readBytes);
- } else {
- stream.reset();
- }
-
- return peekedBytes;
- }
-
-
-
- /**
- * Reads all the data from the input stream, and returns the bytes read.
- */
- public static byte[] toByteArray(InputStream stream) throws IOException {
- return toByteArray(stream, Integer.MAX_VALUE);
- }
-
- /**
- * Reads up to {@code length} bytes from the input stream, and returns the bytes read.
- */
- public static byte[] toByteArray(InputStream stream, int length) throws IOException {
- ByteArrayOutputStream baos = new ByteArrayOutputStream(length == Integer.MAX_VALUE ? 4096 : length);
-
- byte[] buffer = new byte[4096];
- int totalBytes = 0, readBytes;
- do {
- readBytes = stream.read(buffer, 0, Math.min(buffer.length, length-totalBytes));
- totalBytes += Math.max(readBytes,0);
- if (readBytes > 0) {
- baos.write(buffer, 0, readBytes);
- }
- } while (totalBytes < length && readBytes > -1);
-
- if (length != Integer.MAX_VALUE && totalBytes < length) {
- throw new IOException("unexpected EOF");
- }
-
- return baos.toByteArray();
- }
-
-
- /**
- * Returns an array (that shouldn't be written to!) of the
- * ByteBuffer. Will be of the requested length, or possibly
- * longer if that's easier.
- */
- public static byte[] toByteArray(ByteBuffer buffer, int length) {
- if(buffer.hasArray() && buffer.arrayOffset() == 0) {
- // The backing array should work out fine for us
- return buffer.array();
- }
-
- byte[] data = new byte[length];
- buffer.get(data);
- return data;
- }
-
- /**
- * Helper method, just calls <tt>readFully(in, b, 0, b.length)</tt>
- */
- public static int readFully(InputStream in, byte[] b) throws IOException {
- return readFully(in, b, 0, b.length);
- }
-
- /**
- * <p>Same as the normal {@link InputStream#read(byte[], int, int)}, but tries to ensure
- * that the entire len number of bytes is read.</p>
- *
- * <p>If the end of file is reached before any bytes are read, returns <tt>-1</tt>. If
- * the end of the file is reached after some bytes are read, returns the
- * number of bytes read. If the end of the file isn't reached before <tt>len</tt>
- * bytes have been read, will return <tt>len</tt> bytes.</p>
- *
- * @param in the stream from which the data is read.
- * @param b the buffer into which the data is read.
- * @param off the start offset in array <tt>b</tt> at which the data is written.
- * @param len the maximum number of bytes to read.
- */
- public static int readFully(InputStream in, byte[] b, int off, int len) throws IOException {
- int total = 0;
- while (true) {
- int got = in.read(b, off + total, len - total);
- if (got < 0) {
- return (total == 0) ? -1 : total;
- }
- total += got;
- if (total == len) {
- return total;
- }
- }
- }
-
- /**
- * Same as the normal <tt>channel.read(b)</tt>, but tries to ensure
- * that the buffer is filled completely if possible, i.e. b.remaining()
- * returns 0.
- * <p>
- * If the end of file is reached before any bytes are read, returns -1. If
- * the end of the file is reached after some bytes are read, returns the
- * number of bytes read. If the end of the file isn't reached before the
- * buffer has no more remaining capacity, will return the number of bytes
- * that were read.
- */
- public static int readFully(ReadableByteChannel channel, ByteBuffer b) throws IOException {
- int total = 0;
- while (true) {
- int got = channel.read(b);
- if (got < 0) {
- return (total == 0) ? -1 : total;
- }
- total += got;
- if (total == b.capacity() || b.position() == b.capacity()) {
- return total;
- }
- }
- }
-
- /**
- * Write a POI Document ({@link org.apache.poi.ss.usermodel.Workbook}, {@link org.apache.poi.sl.usermodel.SlideShow}, etc) to an output stream and close the output stream.
- * This will attempt to close the output stream at the end even if there was a problem writing the document to the stream.
- *
- * If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead.
- * This function exists for Java 6 code.
- *
- * @param doc a writeable document to write to the output stream
- * @param out the output stream that the document is written to
- * @throws IOException
- */
- public static void write(POIDocument doc, OutputStream out) throws IOException {
- try {
- doc.write(out);
- } finally {
- closeQuietly(out);
- }
- }
-
- /**
- * Write a ({@link org.apache.poi.ss.usermodel.Workbook}) to an output stream and close the output stream.
- * This will attempt to close the output stream at the end even if there was a problem writing the document to the stream.
- *
- * If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead.
- * This function exists for Java 6 code.
- *
- * @param doc a writeable document to write to the output stream
- * @param out the output stream that the document is written to
- * @throws IOException
- */
- public static void write(Workbook doc, OutputStream out) throws IOException {
- try {
- doc.write(out);
- } finally {
- closeQuietly(out);
- }
- }
-
- /**
- * Write a POI Document ({@link org.apache.poi.ss.usermodel.Workbook}, {@link org.apache.poi.sl.usermodel.SlideShow}, etc) to an output stream and close the output stream.
- * This will attempt to close the output stream at the end even if there was a problem writing the document to the stream.
- * This will also attempt to close the document, even if an error occurred while writing the document or closing the output stream.
- *
- * If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead.
- * This function exists for Java 6 code.
- *
- * @param doc a writeable and closeable document to write to the output stream, then close
- * @param out the output stream that the document is written to
- * @throws IOException
- */
- public static void writeAndClose(POIDocument doc, OutputStream out) throws IOException {
- try {
- write(doc, out);
- } finally {
- closeQuietly(doc);
- }
- }
-
- /**
- * Like {@link #writeAndClose(POIDocument, OutputStream)}, but for writing to a File instead of an OutputStream.
- * This will attempt to close the document, even if an error occurred while writing the document.
- *
- * If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead.
- * This function exists for Java 6 code.
- *
- * @param doc a writeable and closeable document to write to the output file, then close
- * @param out the output file that the document is written to
- * @throws IOException
- */
- public static void writeAndClose(POIDocument doc, File out) throws IOException {
- try {
- doc.write(out);
- } finally {
- closeQuietly(doc);
- }
- }
-
- /**
- * Like {@link #writeAndClose(POIDocument, File)}, but for writing a POI Document in place (to the same file that it was opened from).
- * This will attempt to close the document, even if an error occurred while writing the document.
- *
- * If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead.
- * This function exists for Java 6 code.
- *
- * @param doc a writeable document to write in-place
- * @throws IOException
- */
- public static void writeAndClose(POIDocument doc) throws IOException {
- try {
- doc.write();
- } finally {
- closeQuietly(doc);
- }
- }
-
- // Since the Workbook interface doesn't derive from POIDocument
- // We'll likely need one of these for each document container interface
- public static void writeAndClose(Workbook doc, OutputStream out) throws IOException {
- try {
- doc.write(out);
- } finally {
- closeQuietly(doc);
- }
- }
-
- /**
- * Copies all the data from the given InputStream to the OutputStream. It
- * leaves both streams open, so you will still need to close them once done.
- */
- public static void copy(InputStream inp, OutputStream out) throws IOException {
- byte[] buff = new byte[4096];
- int count;
- while ((count = inp.read(buff)) != -1) {
- if (count > 0) {
- out.write(buff, 0, count);
- }
- }
- }
-
- /**
- * Calculate checksum on input data
- */
- public static long calculateChecksum(byte[] data) {
- Checksum sum = new CRC32();
- sum.update(data, 0, data.length);
- return sum.getValue();
- }
-
- /**
- * Calculate checksum on all the data read from input stream.
- *
- * This should be more efficient than the equivalent code
- * {@code IOUtils.calculateChecksum(IOUtils.toByteArray(stream))}
- */
- public static long calculateChecksum(InputStream stream) throws IOException {
- Checksum sum = new CRC32();
-
- byte[] buf = new byte[4096];
- int count;
- while ((count = stream.read(buf)) != -1) {
- if (count > 0) {
- sum.update(buf, 0, count);
- }
- }
- return sum.getValue();
- }
-
-
- /**
- * Quietly (no exceptions) close Closable resource. In case of error it will
- * be printed to {@link IOUtils} class logger.
- *
- * @param closeable
- * resource to close
- */
- public static void closeQuietly( final Closeable closeable ) {
- // no need to log a NullPointerException here
- if(closeable == null) {
- return;
- }
-
- try {
- closeable.close();
- } catch ( Exception exc ) {
- logger.log( POILogger.ERROR, "Unable to close resource: " + exc,
- exc );
- }
- }
-
- /**
- * Skips bytes from a stream. Returns -1L if len > available() or if EOF was hit before
- * the end of the stream.
- *
- * @param in inputstream
- * @param len length to skip
- * @return number of bytes skipped
- * @throws IOException on IOException
- */
- public static long skipFully(InputStream in, long len) throws IOException {
- long total = 0;
- while (true) {
- long toSkip = len-total;
- //check that the stream has the toSkip available
- //FileInputStream can mis-report 20k skipped on a 10k file
- if (toSkip > in.available()) {
- return -1L;
- }
- long got = in.skip(len-total);
- if (got < 0) {
- return -1L;
- } else if (got == 0) {
- got = fallBackToReadFully(len-total, in);
- if (got < 0) {
- return -1L;
- }
- }
- total += got;
- if (total == len) {
- return total;
- }
- }
- }
-
- //an InputStream can return 0 whether or not it hits EOF
- //if it returns 0, back off to readFully to test for -1
- private static long fallBackToReadFully(long lenToRead, InputStream in) throws IOException {
- byte[] buffer = new byte[8192];
- long readSoFar = 0;
-
- while (true) {
- int toSkip = (lenToRead > Integer.MAX_VALUE ||
- (lenToRead-readSoFar) > buffer.length) ? buffer.length : (int)(lenToRead-readSoFar);
- long readNow = readFully(in, buffer, 0, toSkip);
- if (readNow < toSkip) {
- return -1L;
- }
- readSoFar += readNow;
- if (readSoFar == lenToRead) {
- return readSoFar;
- }
- }
- }
- }
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