/*
* Copyright (C) 2007 Google Inc.
*
* 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 com.google.common.io;
import com.google.common.base.Preconditions;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.security.MessageDigest;
import java.util.Arrays;
import java.util.zip.Checksum;
/**
* Provides utility methods for working with byte arrays and I/O streams.
*
* <p>All method parameters must be non-null unless documented otherwise.
*
* @author Chris Nokleberg
* @since 2009.09.15 <b>tentative</b>
*/
public final class ByteStreams {
private static final int BUF_SIZE = 0x1000; // 4K
private ByteStreams() {}
/**
* Returns a factory that will supply instances of
* {@link ByteArrayInputStream} that read from the given byte array.
*
* @param b the input buffer
* @return the factory
*/
public static InputSupplier<ByteArrayInputStream> newInputStreamSupplier(
byte[] b) {
return newInputStreamSupplier(b, 0, b.length);
}
/**
* Returns a factory that will supply instances of
* {@link ByteArrayInputStream} that read from the given byte array.
*
* @param b the input buffer
* @param off the offset in the buffer of the first byte to read
* @param len the maximum number of bytes to read from the buffer
* @return the factory
*/
public static InputSupplier<ByteArrayInputStream> newInputStreamSupplier(
final byte[] b, final int off, final int len) {
return new InputSupplier<ByteArrayInputStream>() {
public ByteArrayInputStream getInput() {
return new ByteArrayInputStream(b, off, len);
}
};
}
/**
* Writes a byte array to an output stream from the given supplier.
*
* @param from the bytes to write
* @param to the output supplier
* @throws IOException if an I/O error occurs
*/
public static void write(byte[] from,
OutputSupplier<? extends OutputStream> to) throws IOException {
Preconditions.checkNotNull(from);
boolean threw = true;
OutputStream out = to.getOutput();
try {
out.write(from);
threw = false;
} finally {
Closeables.close(out, threw);
}
}
/**
* Opens input and output streams from the given suppliers, copies all
* bytes from the input to the output, and closes the streams.
*
* @param from the input factory
* @param to the output factory
* @return the number of bytes copied
* @throws IOException if an I/O error occurs
*/
public static long copy(InputSupplier<? extends InputStream> from,
OutputSupplier<? extends OutputStream> to) throws IOException {
boolean threw = true;
InputStream in = from.getInput();
try {
OutputStream out = to.getOutput();
try {
long count = copy(in, out);
threw = false;
return count;
} finally {
Closeables.close(out, threw);
}
} finally {
Closeables.close(in, threw);
}
}
/**
* Opens an input stream from the supplier, copies all bytes from the
* input to the output, and closes the input stream. Does not close
* or flush the output stream.
*
* @param from the input factory
* @param to the output stream to write to
* @return the number of bytes copied
* @throws IOException if an I/O error occurs
*/
public static long copy(InputSupplier<? extends InputStream> from,
OutputStream to) throws IOException {
boolean threw = true;
InputStream in = from.getInput();
try {
long count = copy(in, to);
threw = false;
return count;
} finally {
Closeables.close(in, threw);
}
}
/**
* Copies all bytes from the input stream to the output stream.
* Does not close or flush either stream.
*
* @param from the input stream to read from
* @param to the output stream to write to
* @return the number of bytes copied
* @throws IOException if an I/O error occurs
*/
public static long copy(InputStream from, OutputStream to)
throws IOException {
byte[] buf = new byte[BUF_SIZE];
long total = 0;
while (true) {
int r = from.read(buf);
if (r == -1) {
break;
}
to.write(buf, 0, r);
total += r;
}
return total;
}
/**
* Copies all bytes from the readable channel to the writable channel.
* Does not close or flush either channel.
*
* @param from the readable channel to read from
* @param to the writable channel to write to
* @return the number of bytes copied
* @throws IOException if an I/O error occurs
*/
public static long copy(ReadableByteChannel from,
WritableByteChannel to) throws IOException {
ByteBuffer buf = ByteBuffer.allocate(BUF_SIZE);
long total = 0;
while (from.read(buf) != -1) {
buf.flip();
while (buf.hasRemaining()) {
total += to.write(buf);
}
buf.clear();
}
return total;
}
/**
* Reads all bytes from an input stream into a byte array.
* Does not close the stream.
*
* @param in the input stream to read from
* @return a byte array containing all the bytes from the stream
* @throws IOException if an I/O error occurs
*/
public static byte[] toByteArray(InputStream in) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
copy(in, out);
return out.toByteArray();
}
/**
* Returns the data from a {@link InputStream} factory as a byte array.
*
* @param supplier the factory
* @throws IOException if an I/O error occurs
*/
public static byte[] toByteArray(
InputSupplier<? extends InputStream> supplier) throws IOException {
boolean threw = true;
InputStream in = supplier.getInput();
try {
byte[] result = toByteArray(in);
threw = false;
return result;
} finally {
Closeables.close(in, threw);
}
}
/**
* Returns a new {@link ByteArrayDataInput} instance to read from the {@code
* bytes} array from the beginning.
*/
public static ByteArrayDataInput newDataInput(byte[] bytes) {
return new ByteArrayDataInputStream(bytes);
}
/**
* Returns a new {@link ByteArrayDataInput} instance to read from the {@code
* bytes} array, starting at the given position.
*
* @throws IndexOutOfBoundsException if {@code start} is negative or greater
* than the length of the array
*/
public static ByteArrayDataInput newDataInput(byte[] bytes, int start) {
Preconditions.checkPositionIndex(start, bytes.length);
return new ByteArrayDataInputStream(bytes, start);
}
private static class ByteArrayDataInputStream implements ByteArrayDataInput {
final DataInput input;
ByteArrayDataInputStream(byte[] bytes) {
this.input = new DataInputStream(new ByteArrayInputStream(bytes));
}
ByteArrayDataInputStream(byte[] bytes, int start) {
this.input = new DataInputStream(
new ByteArrayInputStream(bytes, start, bytes.length - start));
}
/*@Override*/ public void readFully(byte b[]) {
try {
input.readFully(b);
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public void readFully(byte b[], int off, int len) {
try {
input.readFully(b, off, len);
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public int skipBytes(int n) {
try {
return input.skipBytes(n);
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public boolean readBoolean() {
try {
return input.readBoolean();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public byte readByte() {
try {
return input.readByte();
} catch (EOFException e) {
throw new IllegalStateException(e);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public int readUnsignedByte() {
try {
return input.readUnsignedByte();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public short readShort() {
try {
return input.readShort();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public int readUnsignedShort() {
try {
return input.readUnsignedShort();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public char readChar() {
try {
return input.readChar();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public int readInt() {
try {
return input.readInt();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public long readLong() {
try {
return input.readLong();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public float readFloat() {
try {
return input.readFloat();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public double readDouble() {
try {
return input.readDouble();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public String readLine() {
try {
return input.readLine();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/*@Override*/ public String readUTF() {
try {
return input.readUTF();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
}
/**
* Returns a new {@link ByteArrayDataOutput} instance with a default size.
*/
public static ByteArrayDataOutput newDataOutput() {
return new ByteArrayDataOutputStream();
}
/**
* Returns a new {@link ByteArrayDataOutput} instance sized to hold
* {@code size} bytes before resizing.
*
* @throws IllegalArgumentException if {@code size} is negative
*/
public static ByteArrayDataOutput newDataOutput(int size) {
Preconditions.checkArgument(size >= 0, "Invalid size: %s", size);
return new ByteArrayDataOutputStream(size);
}
@SuppressWarnings("deprecation") // for writeBytes
private static class ByteArrayDataOutputStream
implements ByteArrayDataOutput {
final DataOutput output;
final ByteArrayOutputStream byteArrayOutputSteam;
ByteArrayDataOutputStream() {
this(new ByteArrayOutputStream());
}
ByteArrayDataOutputStream(int size) {
this(new ByteArrayOutputStream(size));
}
ByteArrayDataOutputStream(ByteArrayOutputStream byteArrayOutputSteam) {
this.byteArrayOutputSteam = byteArrayOutputSteam;
output = new DataOutputStream(byteArrayOutputSteam);
}
/*@Override*/ public void write(int b) {
try {
output.write(b);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void write(byte[] b) {
try {
output.write(b);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void write(byte[] b, int off, int len) {
try {
output.write(b, off, len);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeBoolean(boolean v) {
try {
output.writeBoolean(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeByte(int v) {
try {
output.writeByte(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeBytes(String s) {
try {
output.writeBytes(s);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeChar(int v) {
try {
output.writeChar(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeChars(String s) {
try {
output.writeChars(s);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeDouble(double v) {
try {
output.writeDouble(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeFloat(float v) {
try {
output.writeFloat(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeInt(int v) {
try {
output.writeInt(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeLong(long v) {
try {
output.writeLong(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeShort(int v) {
try {
output.writeShort(v);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public void writeUTF(String s) {
try {
output.writeUTF(s);
} catch (IOException impossible) {
throw new AssertionError(impossible);
}
}
/*@Override*/ public byte[] toByteArray() {
return byteArrayOutputSteam.toByteArray();
}
}
// TODO: Not all streams support skipping.
/** Returns the length of a supplied input stream, in bytes. */
public static long length(InputSupplier<? extends InputStream> supplier)
throws IOException {
long count = 0;
boolean threw = true;
InputStream in = supplier.getInput();
try {
while (true) {
// We skip only Integer.MAX_VALUE due to JDK overflow bugs.
long amt = in.skip(Integer.MAX_VALUE);
if (amt == 0) {
if (in.read() == -1) {
threw = false;
return count;
}
count++;
} else {
count += amt;
}
}
} finally {
Closeables.close(in, threw);
}
}
/**
* Returns true if the supplied input streams contain the same bytes.
*
* @throws IOException if an I/O error occurs
*/
public static boolean equal(InputSupplier<? extends InputStream> supplier1,
InputSupplier<? extends InputStream> supplier2) throws IOException {
byte[] buf1 = new byte[BUF_SIZE];
byte[] buf2 = new byte[BUF_SIZE];
boolean threw = true;
InputStream in1 = supplier1.getInput();
try {
InputStream in2 = supplier2.getInput();
try {
while (true) {
int read1 = read(in1, buf1, 0, BUF_SIZE);
int read2 = read(in2, buf2, 0, BUF_SIZE);
if (read1 != read2 || !Arrays.equals(buf1, buf2)) {
threw = false;
return false;
} else if (read1 != BUF_SIZE) {
threw = false;
return true;
}
}
} finally {
Closeables.close(in2, threw);
}
} finally {
Closeables.close(in1, threw);
}
}
/**
* Attempts to read enough bytes from the stream to fill the given byte array,
* with the same behavior as {@link DataInput#readFully(byte[])}.
* Does not close the stream.
*
* @param in the input stream to read from.
* @param b the buffer into which the data is read.
* @throws EOFException if this stream reaches the end before reading all
* the bytes.
* @throws IOException if an I/O error occurs.
*/
public static void readFully(InputStream in, byte[] b) throws IOException {
readFully(in, b, 0, b.length);
}
/**
* Attempts to read {@code len} bytes from the stream into the given array
* starting at {@code off}, with the same behavior as
* {@link DataInput#readFully(byte[], int, int)}. Does not close the
* stream.
*
* @param in the input stream to read from.
* @param b the buffer into which the data is read.
* @param off an int specifying the offset into the data.
* @param len an int specifying the number of bytes to read.
* @throws EOFException if this stream reaches the end before reading all
* the bytes.
* @throws IOException if an I/O error occurs.
*/
public static void readFully(InputStream in, byte[] b, int off, int len)
throws IOException {
if (read(in, b, off, len) != len) {
throw new EOFException();
}
}
/**
* Discards {@code n} bytes of data from the input stream. This method
* will block until the full amount has been skipped. Does not close the
* stream.
*
* @param in the input stream to read from
* @param n the number of bytes to skip
* @throws EOFException if this stream reaches the end before skipping all
* the bytes
* @throws IOException if an I/O error occurs, or the stream does not
* support skipping
*/
public static void skipFully(InputStream in, long n) throws IOException {
while (n > 0) {
long amt = in.skip(n);
if (amt == 0) {
// Force a blocking read to avoid infinite loop
if (in.read() == -1) {
throw new EOFException();
}
n--;
} else {
n -= amt;
}
}
}
/**
* Process the bytes of a supplied stream
*
* @param supplier the input stream factory
* @param processor the object to which to pass the bytes of the stream
* @return the result of the byte processor
* @throws IOException if an I/O error occurs
*/
public static <T> T readBytes(InputSupplier<? extends InputStream> supplier,
ByteProcessor<T> processor) throws IOException {
byte[] buf = new byte[BUF_SIZE];
boolean threw = true;
InputStream in = supplier.getInput();
try {
int amt;
do {
amt = in.read(buf);
if (amt == -1) {
threw = false;
break;
}
} while (processor.processBytes(buf, 0, amt));
return processor.getResult();
} finally {
Closeables.close(in, threw);
}
}
/**
* Computes and returns the checksum value for a supplied input stream.
* The checksum object is reset when this method returns successfully.
*
* @param supplier the input stream factory
* @param checksum the checksum object
* @return the result of {@link Checksum#getValue} after updating the
* checksum object with all of the bytes in the stream
* @throws IOException if an I/O error occurs
*/
public static long getChecksum(InputSupplier<? extends InputStream> supplier,
final Checksum checksum) throws IOException {
return readBytes(supplier, new ByteProcessor<Long>() {
public boolean processBytes(byte[] buf, int off, int len) {
checksum.update(buf, off, len);
return true;
}
public Long getResult() {
long result = checksum.getValue();
checksum.reset();
return result;
}
});
}
/**
* Computes and returns the digest value for a supplied input stream.
* The digest object is reset when this method returns successfully.
*
* @param supplier the input stream factory
* @param md the digest object
* @return the result of {@link MessageDigest#digest()} after updating the
* digest object with all of the bytes in the stream
* @throws IOException if an I/O error occurs
*/
public static byte[] getDigest(InputSupplier<? extends InputStream> supplier,
final MessageDigest md) throws IOException {
return readBytes(supplier, new ByteProcessor<byte[]>() {
public boolean processBytes(byte[] buf, int off, int len) {
md.update(buf, off, len);
return true;
}
public byte[] getResult() {
return md.digest();
}
});
}
/**
* Reads some bytes from an input stream and stores them into the buffer array
* {@code b}. This method blocks until {@code len} bytes of input data have
* been read into the array, or end of file is detected. The number of bytes
* read is returned, possibly zero. Does not close the stream.
*
* <p>A caller can detect EOF if the number of bytes read is less than
* {@code len}. All subsequent calls on the same stream will return zero.
*
* <p>If {@code b} is null, a {@code NullPointerException} is thrown. If
* {@code off} is negative, or {@code len} is negative, or {@code off+len} is
* greater than the length of the array {@code b}, then an
* {@code IndexOutOfBoundsException} is thrown. If {@code len} is zero, then
* no bytes are read. Otherwise, the first byte read is stored into element
* {@code b[off]}, the next one into {@code b[off+1]}, and so on. The number
* of bytes read is, at most, equal to {@code len}.
*
* @param in the input stream to read from
* @param b the buffer into which the data is read
* @param off an int specifying the offset into the data
* @param len an int specifying the number of bytes to read
* @return the number of bytes read
* @throws IOException if an I/O error occurs
*/
public static int read(InputStream in, byte[] b, int off, int len)
throws IOException {
if (len < 0) {
throw new IndexOutOfBoundsException("len is negative");
}
int total = 0;
while (total < len) {
int result = in.read(b, off + total, len - total);
if (result == -1) {
break;
}
total += result;
}
return total;
}
/**
* Returns an {@link InputSupplier} that returns input streams from the
* an underlying supplier, where each stream starts at the given
* offset and is limited to the specified number of bytes.
*
* @param supplier the supplier from which to get the raw streams
* @param offset the offset in bytes into the underlying stream where
* the returned streams will start
* @param length the maximum length of the returned streams
* @throws IllegalArgumentException if offset or length are negative
*/
public static InputSupplier<InputStream> slice(
final InputSupplier<? extends InputStream> supplier,
final long offset,
final long length) {
Preconditions.checkNotNull(supplier);
Preconditions.checkArgument(offset >= 0, "offset is negative");
Preconditions.checkArgument(length >= 0, "length is negative");
return new InputSupplier<InputStream>() {
/*@Override*/ public InputStream getInput() throws IOException {
InputStream in = supplier.getInput();
if (offset > 0) {
try {
skipFully(in, offset);
} catch (IOException e) {
Closeables.closeQuietly(in);
throw e;
}
}
return new LimitInputStream(in, length);
}
};
}
/**
* Joins multiple {@link InputStream} suppliers into a single supplier.
* Streams returned from the supplier will contain the concatenated data from
* the streams of the underlying suppliers.
*
* <p>Only one underlying input stream will be open at a time. Closing the
* joined stream will close the open underlying stream.
*
* <p>Reading from the joined stream will throw a {@link NullPointerException}
* if any of the suppliers are null or return null.
*
* @param suppliers the suppliers to concatenate
* @return a supplier that will return a stream containing the concatenated
* stream data
*/
public static InputSupplier<InputStream> join(
final Iterable<? extends InputSupplier<? extends InputStream>> suppliers) {
return new InputSupplier<InputStream>() {
/*@Override*/ public InputStream getInput() throws IOException {
return new MultiInputStream(suppliers.iterator());
}
};
}
/** Varargs form of {@link #join(Iterable)}. */
public static InputSupplier<InputStream> join(
InputSupplier<? extends InputStream>... suppliers) {
return join(Arrays.asList(suppliers));
}
}