/*
* Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package java.io;
/**
* A data output stream lets an application write primitive Java data
* types to an output stream in a portable way. An application can
* then use a data input stream to read the data back in.
*
* @author unascribed
* @see java.io.DataInputStream
* @since 1.0
*/
public
class DataOutputStream extends FilterOutputStream implements DataOutput {
/**
* The number of bytes written to the data output stream so far.
* If this counter overflows, it will be wrapped to Integer.MAX_VALUE.
*/
protected int written;
/**
* bytearr is initialized on demand by writeUTF
*/
private byte[] bytearr = null;
/**
* Creates a new data output stream to write data to the specified
* underlying output stream. The counter {@code written} is
* set to zero.
*
* @param out the underlying output stream, to be saved for later
* use.
* @see java.io.FilterOutputStream#out
*/
public DataOutputStream(OutputStream out) {
super(out);
}
/**
* Increases the written counter by the specified value
* until it reaches Integer.MAX_VALUE.
*/
private void incCount(int value) {
int temp = written + value;
if (temp < 0) {
temp = Integer.MAX_VALUE;
}
written = temp;
}
/**
* Writes the specified byte (the low eight bits of the argument
* {@code b}) to the underlying output stream. If no exception
* is thrown, the counter {@code written} is incremented by
* {@code 1}.
* <p>
* Implements the {@code write} method of {@code OutputStream}.
*
* @param b the {@code byte} to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public synchronized void write(int b) throws IOException {
out.write(b);
incCount(1);
}
/**
* Writes {@code len} bytes from the specified byte array
* starting at offset {@code off} to the underlying output stream.
* If no exception is thrown, the counter {@code written} is
* incremented by {@code len}.
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public synchronized void write(byte b[], int off, int len)
throws IOException
{
out.write(b, off, len);
incCount(len);
}
/**
* Flushes this data output stream. This forces any buffered output
* bytes to be written out to the stream.
* <p>
* The {@code flush} method of {@code DataOutputStream}
* calls the {@code flush} method of its underlying output stream.
*
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
* @see java.io.OutputStream#flush()
*/
public void flush() throws IOException {
out.flush();
}
/**
* Writes a {@code boolean} to the underlying output stream as
* a 1-byte value. The value {@code true} is written out as the
* value {@code (byte)1}; the value {@code false} is
* written out as the value {@code (byte)0}. If no exception is
* thrown, the counter {@code written} is incremented by
* {@code 1}.
*
* @param v a {@code boolean} value to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeBoolean(boolean v) throws IOException {
out.write(v ? 1 : 0);
incCount(1);
}
/**
* Writes out a {@code byte} to the underlying output stream as
* a 1-byte value. If no exception is thrown, the counter
* {@code written} is incremented by {@code 1}.
*
* @param v a {@code byte} value to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeByte(int v) throws IOException {
out.write(v);
incCount(1);
}
/**
* Writes a {@code short} to the underlying output stream as two
* bytes, high byte first. If no exception is thrown, the counter
* {@code written} is incremented by {@code 2}.
*
* @param v a {@code short} to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeShort(int v) throws IOException {
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
incCount(2);
}
/**
* Writes a {@code char} to the underlying output stream as a
* 2-byte value, high byte first. If no exception is thrown, the
* counter {@code written} is incremented by {@code 2}.
*
* @param v a {@code char} value to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeChar(int v) throws IOException {
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
incCount(2);
}
/**
* Writes an {@code int} to the underlying output stream as four
* bytes, high byte first. If no exception is thrown, the counter
* {@code written} is incremented by {@code 4}.
*
* @param v an {@code int} to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeInt(int v) throws IOException {
out.write((v >>> 24) & 0xFF);
out.write((v >>> 16) & 0xFF);
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
incCount(4);
}
private byte writeBuffer[] = new byte[8];
/**
* Writes a {@code long} to the underlying output stream as eight
* bytes, high byte first. In no exception is thrown, the counter
* {@code written} is incremented by {@code 8}.
*
* @param v a {@code long} to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeLong(long v) throws IOException {
writeBuffer[0] = (byte)(v >>> 56);
writeBuffer[1] = (byte)(v >>> 48);
writeBuffer[2] = (byte)(v >>> 40);
writeBuffer[3] = (byte)(v >>> 32);
writeBuffer[4] = (byte)(v >>> 24);
writeBuffer[5] = (byte)(v >>> 16);
writeBuffer[6] = (byte)(v >>> 8);
writeBuffer[7] = (byte)(v >>> 0);
out.write(writeBuffer, 0, 8);
incCount(8);
}
/**
* Converts the float argument to an {@code int} using the
* {@code floatToIntBits} method in class {@code Float},
* and then writes that {@code int} value to the underlying
* output stream as a 4-byte quantity, high byte first. If no
* exception is thrown, the counter {@code written} is
* incremented by {@code 4}.
*
* @param v a {@code float} value to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
* @see java.lang.Float#floatToIntBits(float)
*/
public final void writeFloat(float v) throws IOException {
writeInt(Float.floatToIntBits(v));
}
/**
* Converts the double argument to a {@code long} using the
* {@code doubleToLongBits} method in class {@code Double},
* and then writes that {@code long} value to the underlying
* output stream as an 8-byte quantity, high byte first. If no
* exception is thrown, the counter {@code written} is
* incremented by {@code 8}.
*
* @param v a {@code double} value to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
* @see java.lang.Double#doubleToLongBits(double)
*/
public final void writeDouble(double v) throws IOException {
writeLong(Double.doubleToLongBits(v));
}
/**
* Writes out the string to the underlying output stream as a
* sequence of bytes. Each character in the string is written out, in
* sequence, by discarding its high eight bits. If no exception is
* thrown, the counter {@code written} is incremented by the
* length of {@code s}.
*
* @param s a string of bytes to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeBytes(String s) throws IOException {
int len = s.length();
for (int i = 0 ; i < len ; i++) {
out.write((byte)s.charAt(i));
}
incCount(len);
}
/**
* Writes a string to the underlying output stream as a sequence of
* characters. Each character is written to the data output stream as
* if by the {@code writeChar} method. If no exception is
* thrown, the counter {@code written} is incremented by twice
* the length of {@code s}.
*
* @param s a {@code String} value to be written.
* @throws IOException if an I/O error occurs.
* @see java.io.DataOutputStream#writeChar(int)
* @see java.io.FilterOutputStream#out
*/
public final void writeChars(String s) throws IOException {
int len = s.length();
for (int i = 0 ; i < len ; i++) {
int v = s.charAt(i);
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
}
incCount(len * 2);
}
/**
* Writes a string to the underlying output stream using
* <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
* encoding in a machine-independent manner.
* <p>
* First, two bytes are written to the output stream as if by the
* {@code writeShort} method giving the number of bytes to
* follow. This value is the number of bytes actually written out,
* not the length of the string. Following the length, each character
* of the string is output, in sequence, using the modified UTF-8 encoding
* for the character. If no exception is thrown, the counter
* {@code written} is incremented by the total number of
* bytes written to the output stream. This will be at least two
* plus the length of {@code str}, and at most two plus
* thrice the length of {@code str}.
*
* @param str a string to be written.
* @throws UTFDataFormatException if the modified UTF-8 encoding of
* {@code str} would exceed 65535 bytes in length
* @throws IOException if some other I/O error occurs.
* @see #writeChars(String)
*/
public final void writeUTF(String str) throws IOException {
writeUTF(str, this);
}
/**
* Writes a string to the specified DataOutput using
* <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
* encoding in a machine-independent manner.
* <p>
* First, two bytes are written to out as if by the {@code writeShort}
* method giving the number of bytes to follow. This value is the number of
* bytes actually written out, not the length of the string. Following the
* length, each character of the string is output, in sequence, using the
* modified UTF-8 encoding for the character. If no exception is thrown, the
* counter {@code written} is incremented by the total number of
* bytes written to the output stream. This will be at least two
* plus the length of {@code str}, and at most two plus
* thrice the length of {@code str}.
*
* @param str a string to be written.
* @param out destination to write to
* @return The number of bytes written out.
* @throws UTFDataFormatException if the modified UTF-8 encoding of
* {@code str} would exceed 65535 bytes in length
* @throws IOException if some other I/O error occurs.
*/
static int writeUTF(String str, DataOutput out) throws IOException {
final int strlen = str.length();
int utflen = strlen; // optimized for ASCII
for (int i = 0; i < strlen; i++) {
int c = str.charAt(i);
if (c >= 0x80 || c == 0)
utflen += (c >= 0x800) ? 2 : 1;
}
if (utflen > 65535 || /* overflow */ utflen < strlen)
throw new UTFDataFormatException(tooLongMsg(str, utflen));
final byte[] bytearr;
if (out instanceof DataOutputStream) {
DataOutputStream dos = (DataOutputStream)out;
if (dos.bytearr == null || (dos.bytearr.length < (utflen + 2)))
dos.bytearr = new byte[(utflen*2) + 2];
bytearr = dos.bytearr;
} else {
bytearr = new byte[utflen + 2];
}
int count = 0;
bytearr[count++] = (byte) ((utflen >>> 8) & 0xFF);
bytearr[count++] = (byte) ((utflen >>> 0) & 0xFF);
int i = 0;
for (i = 0; i < strlen; i++) { // optimized for initial run of ASCII
int c = str.charAt(i);
if (c >= 0x80 || c == 0) break;
bytearr[count++] = (byte) c;
}
for (; i < strlen; i++) {
int c = str.charAt(i);
if (c < 0x80 && c != 0) {
bytearr[count++] = (byte) c;
} else if (c >= 0x800) {
bytearr[count++] = (byte) (0xE0 | ((c >> 12) & 0x0F));
bytearr[count++] = (byte) (0x80 | ((c >> 6) & 0x3F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
} else {
bytearr[count++] = (byte) (0xC0 | ((c >> 6) & 0x1F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
}
}
out.write(bytearr, 0, utflen + 2);
return utflen + 2;
}
private static String tooLongMsg(String s, int bits32) {
int slen = s.length();
String head = s.substring(0, 8);
String tail = s.substring(slen - 8, slen);
// handle int overflow with max 3x expansion
long actualLength = (long)slen + Integer.toUnsignedLong(bits32 - slen);
return "encoded string (" + head + "..." + tail + ") too long: "
+ actualLength + " bytes";
}
/**
* Returns the current value of the counter {@code written},
* the number of bytes written to this data output stream so far.
* If the counter overflows, it will be wrapped to Integer.MAX_VALUE.
*
* @return the value of the {@code written} field.
* @see java.io.DataOutputStream#written
*/
public final int size() {
return written;
}
}