| /* LineInputStream.java -- |
| Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.net; |
| |
| import java.io.BufferedInputStream; |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * An input stream that can read lines of input. |
| * |
| * @author Chris Burdess (dog@gnu.org) |
| */ |
| public class LineInputStream |
| extends InputStream |
| { |
| |
| /** |
| * The underlying input stream. |
| */ |
| protected InputStream in; |
| |
| /* |
| * Line buffer. |
| */ |
| private ByteArrayOutputStream buf; |
| |
| /* |
| * Encoding to use when translating bytes to characters. |
| */ |
| private String encoding; |
| |
| /* |
| * End-of-stream flag. |
| */ |
| private boolean eof; |
| |
| /** |
| * Whether we can use block reads. |
| */ |
| private final boolean blockReads; |
| |
| /** |
| * Constructor using the US-ASCII character encoding. |
| * @param in the underlying input stream |
| */ |
| public LineInputStream(InputStream in) |
| { |
| this(in, "US-ASCII"); |
| } |
| |
| /** |
| * Constructor. |
| * @param in the underlying input stream |
| * @param encoding the character encoding to use |
| */ |
| public LineInputStream(InputStream in, String encoding) |
| { |
| this.in = in; |
| buf = new ByteArrayOutputStream(); |
| this.encoding = encoding; |
| eof = false; |
| // If it is already buffered, additional buffering gains nothing. |
| blockReads = !(in instanceof BufferedInputStream) && in.markSupported(); |
| } |
| |
| public int read() |
| throws IOException |
| { |
| return in.read(); |
| } |
| |
| public int read(byte[] buf) |
| throws IOException |
| { |
| return in.read(buf); |
| } |
| |
| public int read(byte[] buf, int off, int len) |
| throws IOException |
| { |
| return in.read(buf, off, len); |
| } |
| |
| /** |
| * Read a line of input. |
| */ |
| public String readLine() |
| throws IOException |
| { |
| if (eof) |
| { |
| return null; |
| } |
| do |
| { |
| if (blockReads) |
| { |
| // Use mark and reset to read chunks of bytes |
| final int MAX_LENGTH = 1024; |
| int len, pos; |
| |
| len = in.available(); |
| if (len == 0 || len > MAX_LENGTH) |
| len = MAX_LENGTH; |
| byte[] b = new byte[len]; |
| in.mark(len); |
| // Read into buffer b |
| len = in.read(b, 0, len); |
| // Handle EOF |
| if (len == -1) |
| { |
| eof = true; |
| if (buf.size() == 0) |
| { |
| return null; |
| } |
| else |
| { |
| // We don't care about resetting buf |
| return buf.toString(encoding); |
| } |
| } |
| // Get index of LF in b |
| pos = indexOf(b, len, (byte) 0x0a); |
| if (pos != -1) |
| { |
| // Write pos bytes to buf |
| buf.write(b, 0, pos); |
| // Reset stream, and read pos + 1 bytes |
| in.reset(); |
| pos += 1; |
| while (pos > 0) |
| { |
| len = in.read(b, 0, pos); |
| pos = (len == -1) ? -1 : pos - len; |
| } |
| // Return line |
| String ret = buf.toString(encoding); |
| buf.reset(); |
| return ret; |
| } |
| else |
| { |
| // Append everything to buf and fall through to re-read. |
| buf.write(b, 0, len); |
| } |
| } |
| else |
| { |
| // We must use character reads in order not to read too much |
| // from the underlying stream. |
| int c = in.read(); |
| switch (c) |
| { |
| case -1: |
| eof = true; |
| if (buf.size() == 0) |
| { |
| return null; |
| } |
| // Fall through and return contents of buffer. |
| case 0x0a: // LF |
| String ret = buf.toString(encoding); |
| buf.reset(); |
| return ret; |
| default: |
| buf.write(c); |
| } |
| } |
| } |
| while (true); |
| } |
| |
| private int indexOf(byte[] b, int len, byte c) |
| { |
| for (int pos = 0; pos < len; pos++) |
| { |
| if (b[pos] == c) |
| { |
| return pos; |
| } |
| } |
| return -1; |
| } |
| } |
| |