294 lines
10 KiB
Java
294 lines
10 KiB
Java
/*
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* Copyright (c) 1995, 2012, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.io;
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/**
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* This class is an input stream filter that provides the added
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* functionality of keeping track of the current line number.
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* <p>
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* A line is a sequence of bytes ending with a carriage return
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* character ({@code '\u005Cr'}), a newline character
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* ({@code '\u005Cn'}), or a carriage return character followed
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* immediately by a linefeed character. In all three cases, the line
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* terminating character(s) are returned as a single newline character.
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* <p>
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* The line number begins at {@code 0}, and is incremented by
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* {@code 1} when a {@code read} returns a newline character.
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*
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* @author Arthur van Hoff
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* @see java.io.LineNumberReader
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* @since 1.0
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* @deprecated This class incorrectly assumes that bytes adequately represent
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* characters. As of JDK 1.1, the preferred way to operate on
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* character streams is via the new character-stream classes, which
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* include a class for counting line numbers.
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*/
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@Deprecated
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public
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class LineNumberInputStream extends FilterInputStream {
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int pushBack = -1;
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int lineNumber;
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int markLineNumber;
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int markPushBack = -1;
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/**
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* Constructs a newline number input stream that reads its input
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* from the specified input stream.
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*
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* @param in the underlying input stream.
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*/
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public LineNumberInputStream(InputStream in) {
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super(in);
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}
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/**
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* Reads the next byte of data from this input stream. The value
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* byte is returned as an {@code int} in the range
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* {@code 0} to {@code 255}. If no byte is available
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* because the end of the stream has been reached, the value
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* {@code -1} is returned. This method blocks until input data
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* is available, the end of the stream is detected, or an exception
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* is thrown.
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* <p>
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* The {@code read} method of
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* {@code LineNumberInputStream} calls the {@code read}
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* method of the underlying input stream. It checks for carriage
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* returns and newline characters in the input, and modifies the
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* current line number as appropriate. A carriage-return character or
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* a carriage return followed by a newline character are both
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* converted into a single newline character.
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*
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* @return the next byte of data, or {@code -1} if the end of this
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* stream is reached.
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* @exception IOException if an I/O error occurs.
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* @see java.io.FilterInputStream#in
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* @see java.io.LineNumberInputStream#getLineNumber()
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*/
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@SuppressWarnings("fallthrough")
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public int read() throws IOException {
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int c = pushBack;
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if (c != -1) {
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pushBack = -1;
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} else {
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c = in.read();
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}
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switch (c) {
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case '\r':
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pushBack = in.read();
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if (pushBack == '\n') {
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pushBack = -1;
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}
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case '\n':
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lineNumber++;
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return '\n';
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}
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return c;
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}
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/**
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* Reads up to {@code len} bytes of data from this input stream
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* into an array of bytes. This method blocks until some input is available.
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* <p>
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* The {@code read} method of
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* {@code LineNumberInputStream} repeatedly calls the
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* {@code read} method of zero arguments to fill in the byte array.
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*
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* @param b the buffer into which the data is read.
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* @param off the start offset of the data.
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* @param len the maximum number of bytes read.
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* @return the total number of bytes read into the buffer, or
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* {@code -1} if there is no more data because the end of
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* this stream has been reached.
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* @exception IOException if an I/O error occurs.
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* @see java.io.LineNumberInputStream#read()
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*/
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public int read(byte b[], int off, int len) throws IOException {
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if (b == null) {
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throw new NullPointerException();
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} else if ((off < 0) || (off > b.length) || (len < 0) ||
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((off + len) > b.length) || ((off + len) < 0)) {
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throw new IndexOutOfBoundsException();
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} else if (len == 0) {
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return 0;
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}
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int c = read();
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if (c == -1) {
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return -1;
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}
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b[off] = (byte)c;
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int i = 1;
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try {
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for (; i < len ; i++) {
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c = read();
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if (c == -1) {
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break;
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}
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if (b != null) {
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b[off + i] = (byte)c;
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}
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}
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} catch (IOException ee) {
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}
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return i;
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}
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/**
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* Skips over and discards {@code n} bytes of data from this
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* input stream. The {@code skip} method may, for a variety of
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* reasons, end up skipping over some smaller number of bytes,
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* possibly {@code 0}. The actual number of bytes skipped is
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* returned. If {@code n} is negative, no bytes are skipped.
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* <p>
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* The {@code skip} method of {@code LineNumberInputStream} creates
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* a byte array and then repeatedly reads into it until
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* {@code n} bytes have been read or the end of the stream has
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* been reached.
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*
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* @param n the number of bytes to be skipped.
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* @return the actual number of bytes skipped.
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* @exception IOException if an I/O error occurs.
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* @see java.io.FilterInputStream#in
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*/
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public long skip(long n) throws IOException {
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int chunk = 2048;
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long remaining = n;
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byte data[];
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int nr;
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if (n <= 0) {
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return 0;
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}
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data = new byte[chunk];
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while (remaining > 0) {
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nr = read(data, 0, (int) Math.min(chunk, remaining));
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if (nr < 0) {
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break;
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}
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remaining -= nr;
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}
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return n - remaining;
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}
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/**
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* Sets the line number to the specified argument.
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*
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* @param lineNumber the new line number.
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* @see #getLineNumber
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*/
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public void setLineNumber(int lineNumber) {
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this.lineNumber = lineNumber;
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}
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/**
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* Returns the current line number.
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*
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* @return the current line number.
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* @see #setLineNumber
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*/
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public int getLineNumber() {
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return lineNumber;
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}
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/**
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* Returns the number of bytes that can be read from this input
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* stream without blocking.
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* <p>
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* Note that if the underlying input stream is able to supply
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* <i>k</i> input characters without blocking, the
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* {@code LineNumberInputStream} can guarantee only to provide
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* <i>k</i>/2 characters without blocking, because the
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* <i>k</i> characters from the underlying input stream might
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* consist of <i>k</i>/2 pairs of {@code '\u005Cr'} and
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* {@code '\u005Cn'}, which are converted to just
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* <i>k</i>/2 {@code '\u005Cn'} characters.
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*
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* @return the number of bytes that can be read from this input stream
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* without blocking.
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* @exception IOException if an I/O error occurs.
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* @see java.io.FilterInputStream#in
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*/
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public int available() throws IOException {
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return (pushBack == -1) ? super.available()/2 : super.available()/2 + 1;
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}
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/**
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* Marks the current position in this input stream. A subsequent
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* call to the {@code reset} method repositions this stream at
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* the last marked position so that subsequent reads re-read the same bytes.
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* <p>
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* The {@code mark} method of
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* {@code LineNumberInputStream} remembers the current line
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* number in a private variable, and then calls the {@code mark}
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* method of the underlying input stream.
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*
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* @param readlimit the maximum limit of bytes that can be read before
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* the mark position becomes invalid.
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* @see java.io.FilterInputStream#in
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* @see java.io.LineNumberInputStream#reset()
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*/
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public void mark(int readlimit) {
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markLineNumber = lineNumber;
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markPushBack = pushBack;
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in.mark(readlimit);
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}
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/**
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* Repositions this stream to the position at the time the
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* {@code mark} method was last called on this input stream.
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* <p>
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* The {@code reset} method of
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* {@code LineNumberInputStream} resets the line number to be
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* the line number at the time the {@code mark} method was
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* called, and then calls the {@code reset} method of the
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* underlying input stream.
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* <p>
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* Stream marks are intended to be used in
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* situations where you need to read ahead a little to see what's in
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* the stream. Often this is most easily done by invoking some
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* general parser. If the stream is of the type handled by the
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* parser, it just chugs along happily. If the stream is not of
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* that type, the parser should toss an exception when it fails,
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* which, if it happens within readlimit bytes, allows the outer
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* code to reset the stream and try another parser.
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*
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* @exception IOException if an I/O error occurs.
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* @see java.io.FilterInputStream#in
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* @see java.io.LineNumberInputStream#mark(int)
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*/
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public void reset() throws IOException {
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lineNumber = markLineNumber;
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pushBack = markPushBack;
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in.reset();
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}
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}
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