| /* InputStreamReader.java -- Reader than transforms bytes to chars |
| Copyright (C) 1998, 1999, 2001, 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 java.io; |
| |
| import gnu.classpath.SystemProperties; |
| import gnu.java.nio.charset.EncodingHelper; |
| |
| import java.nio.ByteBuffer; |
| import java.nio.CharBuffer; |
| import java.nio.charset.Charset; |
| import java.nio.charset.CharsetDecoder; |
| import java.nio.charset.CoderResult; |
| import java.nio.charset.CodingErrorAction; |
| |
| /** |
| * This class reads characters from a byte input stream. The characters |
| * read are converted from bytes in the underlying stream by a |
| * decoding layer. The decoding layer transforms bytes to chars according |
| * to an encoding standard. There are many available encodings to choose |
| * from. The desired encoding can either be specified by name, or if no |
| * encoding is selected, the system default encoding will be used. The |
| * system default encoding name is determined from the system property |
| * <code>file.encoding</code>. The only encodings that are guaranteed to |
| * be availalbe are "8859_1" (the Latin-1 character set) and "UTF8". |
| * Unforunately, Java does not provide a mechanism for listing the |
| * ecodings that are supported in a given implementation. |
| * <p> |
| * Here is a list of standard encoding names that may be available: |
| * <p> |
| * <ul> |
| * <li>8859_1 (ISO-8859-1/Latin-1)</li> |
| * <li>8859_2 (ISO-8859-2/Latin-2)</li> |
| * <li>8859_3 (ISO-8859-3/Latin-3)</li> |
| * <li>8859_4 (ISO-8859-4/Latin-4)</li> |
| * <li>8859_5 (ISO-8859-5/Latin-5)</li> |
| * <li>8859_6 (ISO-8859-6/Latin-6)</li> |
| * <li>8859_7 (ISO-8859-7/Latin-7)</li> |
| * <li>8859_8 (ISO-8859-8/Latin-8)</li> |
| * <li>8859_9 (ISO-8859-9/Latin-9)</li> |
| * <li>ASCII (7-bit ASCII)</li> |
| * <li>UTF8 (UCS Transformation Format-8)</li> |
| * <li>More later</li> |
| * </ul> |
| * <p> |
| * It is recommended that applications do not use |
| * <code>InputStreamReader</code>'s |
| * directly. Rather, for efficiency purposes, an object of this class |
| * should be wrapped by a <code>BufferedReader</code>. |
| * <p> |
| * Due to a deficiency the Java class library design, there is no standard |
| * way for an application to install its own byte-character encoding. |
| * |
| * @see BufferedReader |
| * @see InputStream |
| * |
| * @author Robert Schuster |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @author Per Bothner (bothner@cygnus.com) |
| * @date April 22, 1998. |
| */ |
| public class InputStreamReader extends Reader |
| { |
| /** |
| * The input stream. |
| */ |
| private InputStream in; |
| |
| /** |
| * The charset decoder. |
| */ |
| private CharsetDecoder decoder; |
| |
| /** |
| * End of stream reached. |
| */ |
| private boolean isDone = false; |
| |
| /** |
| * Need this. |
| */ |
| private float maxBytesPerChar; |
| |
| /** |
| * Buffer holding surplus loaded bytes (if any) |
| */ |
| private ByteBuffer byteBuffer; |
| |
| /** |
| * java.io canonical name of the encoding. |
| */ |
| private String encoding; |
| |
| /** |
| * We might decode to a 2-char UTF-16 surrogate, which won't fit in the |
| * output buffer. In this case we need to save the surrogate char. |
| */ |
| private char savedSurrogate; |
| private boolean hasSavedSurrogate = false; |
| |
| /** |
| * This method initializes a new instance of <code>InputStreamReader</code> |
| * to read from the specified stream using the default encoding. |
| * |
| * @param in The <code>InputStream</code> to read from |
| */ |
| public InputStreamReader(InputStream in) |
| { |
| if (in == null) |
| throw new NullPointerException(); |
| this.in = in; |
| try |
| { |
| encoding = SystemProperties.getProperty("file.encoding"); |
| // Don't use NIO if avoidable |
| if(EncodingHelper.isISOLatin1(encoding)) |
| { |
| encoding = "ISO8859_1"; |
| maxBytesPerChar = 1f; |
| decoder = null; |
| return; |
| } |
| Charset cs = EncodingHelper.getCharset(encoding); |
| decoder = cs.newDecoder(); |
| encoding = EncodingHelper.getOldCanonical(cs.name()); |
| try { |
| maxBytesPerChar = cs.newEncoder().maxBytesPerChar(); |
| } catch(UnsupportedOperationException _){ |
| maxBytesPerChar = 1f; |
| } |
| decoder.onMalformedInput(CodingErrorAction.REPLACE); |
| decoder.onUnmappableCharacter(CodingErrorAction.REPLACE); |
| decoder.reset(); |
| } catch(RuntimeException e) { |
| encoding = "ISO8859_1"; |
| maxBytesPerChar = 1f; |
| decoder = null; |
| } catch(UnsupportedEncodingException e) { |
| encoding = "ISO8859_1"; |
| maxBytesPerChar = 1f; |
| decoder = null; |
| } |
| } |
| |
| /** |
| * This method initializes a new instance of <code>InputStreamReader</code> |
| * to read from the specified stream using a caller supplied character |
| * encoding scheme. Note that due to a deficiency in the Java language |
| * design, there is no way to determine which encodings are supported. |
| * |
| * @param in The <code>InputStream</code> to read from |
| * @param encoding_name The name of the encoding scheme to use |
| * |
| * @exception UnsupportedEncodingException If the encoding scheme |
| * requested is not available. |
| */ |
| public InputStreamReader(InputStream in, String encoding_name) |
| throws UnsupportedEncodingException |
| { |
| if (in == null |
| || encoding_name == null) |
| throw new NullPointerException(); |
| |
| this.in = in; |
| // Don't use NIO if avoidable |
| if(EncodingHelper.isISOLatin1(encoding_name)) |
| { |
| encoding = "ISO8859_1"; |
| maxBytesPerChar = 1f; |
| decoder = null; |
| return; |
| } |
| try { |
| Charset cs = EncodingHelper.getCharset(encoding_name); |
| try { |
| maxBytesPerChar = cs.newEncoder().maxBytesPerChar(); |
| } catch(UnsupportedOperationException _){ |
| maxBytesPerChar = 1f; |
| } |
| |
| decoder = cs.newDecoder(); |
| decoder.onMalformedInput(CodingErrorAction.REPLACE); |
| decoder.onUnmappableCharacter(CodingErrorAction.REPLACE); |
| decoder.reset(); |
| |
| // The encoding should be the old name, if such exists. |
| encoding = EncodingHelper.getOldCanonical(cs.name()); |
| } catch(RuntimeException e) { |
| encoding = "ISO8859_1"; |
| maxBytesPerChar = 1f; |
| decoder = null; |
| } |
| } |
| |
| /** |
| * Creates an InputStreamReader that uses a decoder of the given |
| * charset to decode the bytes in the InputStream into |
| * characters. |
| * |
| * @since 1.4 |
| */ |
| public InputStreamReader(InputStream in, Charset charset) { |
| if (in == null) |
| throw new NullPointerException(); |
| this.in = in; |
| decoder = charset.newDecoder(); |
| |
| try { |
| maxBytesPerChar = charset.newEncoder().maxBytesPerChar(); |
| } catch(UnsupportedOperationException _){ |
| maxBytesPerChar = 1f; |
| } |
| |
| decoder.onMalformedInput(CodingErrorAction.REPLACE); |
| decoder.onUnmappableCharacter(CodingErrorAction.REPLACE); |
| decoder.reset(); |
| encoding = EncodingHelper.getOldCanonical(charset.name()); |
| } |
| |
| /** |
| * Creates an InputStreamReader that uses the given charset decoder |
| * to decode the bytes in the InputStream into characters. |
| * |
| * @since 1.4 |
| */ |
| public InputStreamReader(InputStream in, CharsetDecoder decoder) { |
| if (in == null) |
| throw new NullPointerException(); |
| this.in = in; |
| this.decoder = decoder; |
| |
| Charset charset = decoder.charset(); |
| try { |
| if (charset == null) |
| maxBytesPerChar = 1f; |
| else |
| maxBytesPerChar = charset.newEncoder().maxBytesPerChar(); |
| } catch(UnsupportedOperationException _){ |
| maxBytesPerChar = 1f; |
| } |
| |
| decoder.onMalformedInput(CodingErrorAction.REPLACE); |
| decoder.onUnmappableCharacter(CodingErrorAction.REPLACE); |
| decoder.reset(); |
| if (charset == null) |
| encoding = "US-ASCII"; |
| else |
| encoding = EncodingHelper.getOldCanonical(decoder.charset().name()); |
| } |
| |
| /** |
| * This method closes this stream, as well as the underlying |
| * <code>InputStream</code>. |
| * |
| * @exception IOException If an error occurs |
| */ |
| public void close() throws IOException |
| { |
| synchronized (lock) |
| { |
| // Makes sure all intermediate data is released by the decoder. |
| if (decoder != null) |
| decoder.reset(); |
| if (in != null) |
| in.close(); |
| in = null; |
| isDone = true; |
| decoder = null; |
| } |
| } |
| |
| /** |
| * This method returns the name of the encoding that is currently in use |
| * by this object. If the stream has been closed, this method is allowed |
| * to return <code>null</code>. |
| * |
| * @return The current encoding name |
| */ |
| public String getEncoding() |
| { |
| return in != null ? encoding : null; |
| } |
| |
| /** |
| * This method checks to see if the stream is ready to be read. It |
| * will return <code>true</code> if is, or <code>false</code> if it is not. |
| * If the stream is not ready to be read, it could (although is not required |
| * to) block on the next read attempt. |
| * |
| * @return <code>true</code> if the stream is ready to be read, |
| * <code>false</code> otherwise |
| * |
| * @exception IOException If an error occurs |
| */ |
| public boolean ready() throws IOException |
| { |
| if (in == null) |
| throw new IOException("Reader has been closed"); |
| |
| return in.available() != 0; |
| } |
| |
| /** |
| * This method reads up to <code>length</code> characters from the stream into |
| * the specified array starting at index <code>offset</code> into the |
| * array. |
| * |
| * @param buf The character array to recieve the data read |
| * @param offset The offset into the array to start storing characters |
| * @param length The requested number of characters to read. |
| * |
| * @return The actual number of characters read, or -1 if end of stream. |
| * |
| * @exception IOException If an error occurs |
| */ |
| public int read(char[] buf, int offset, int length) throws IOException |
| { |
| if (in == null) |
| throw new IOException("Reader has been closed"); |
| if (isDone) |
| return -1; |
| if(decoder != null){ |
| int totalBytes = (int)((double)length * maxBytesPerChar); |
| byte[] bytes = new byte[totalBytes]; |
| |
| int remaining = 0; |
| if(byteBuffer != null) |
| { |
| remaining = byteBuffer.remaining(); |
| byteBuffer.get(bytes, 0, remaining); |
| } |
| int read; |
| if(totalBytes - remaining > 0) |
| { |
| read = in.read(bytes, remaining, totalBytes - remaining); |
| if(read == -1){ |
| read = remaining; |
| isDone = true; |
| } else |
| read += remaining; |
| } else |
| read = remaining; |
| byteBuffer = ByteBuffer.wrap(bytes, 0, read); |
| CharBuffer cb = CharBuffer.wrap(buf, offset, length); |
| int startPos = cb.position(); |
| |
| if(hasSavedSurrogate){ |
| hasSavedSurrogate = false; |
| cb.put(savedSurrogate); |
| read++; |
| } |
| |
| CoderResult cr = decoder.decode(byteBuffer, cb, isDone); |
| decoder.reset(); |
| // 1 char remains which is the first half of a surrogate pair. |
| if(cr.isOverflow() && cb.hasRemaining()){ |
| CharBuffer overflowbuf = CharBuffer.allocate(2); |
| cr = decoder.decode(byteBuffer, overflowbuf, isDone); |
| overflowbuf.flip(); |
| if(overflowbuf.hasRemaining()) |
| { |
| cb.put(overflowbuf.get()); |
| savedSurrogate = overflowbuf.get(); |
| hasSavedSurrogate = true; |
| isDone = false; |
| } |
| } |
| |
| if(byteBuffer.hasRemaining()) { |
| byteBuffer.compact(); |
| byteBuffer.flip(); |
| isDone = false; |
| } else |
| byteBuffer = null; |
| |
| read = cb.position() - startPos; |
| return (read <= 0) ? -1 : read; |
| } else { |
| byte[] bytes = new byte[length]; |
| int read = in.read(bytes); |
| for(int i=0;i<read;i++) |
| buf[offset+i] = (char)(bytes[i]&0xFF); |
| return read; |
| } |
| } |
| |
| /** |
| * Reads an char from the input stream and returns it |
| * as an int in the range of 0-65535. This method also will return -1 if |
| * the end of the stream has been reached. |
| * <p> |
| * This method will block until the char can be read. |
| * |
| * @return The char read or -1 if end of stream |
| * |
| * @exception IOException If an error occurs |
| */ |
| public int read() throws IOException |
| { |
| char[] buf = new char[1]; |
| int count = read(buf, 0, 1); |
| return count > 0 ? buf[0] : -1; |
| } |
| |
| /** |
| * Skips the specified number of chars in the stream. It |
| * returns the actual number of chars skipped, which may be less than the |
| * requested amount. |
| * |
| * @param count The requested number of chars to skip |
| * |
| * @return The actual number of chars skipped. |
| * |
| * @exception IOException If an error occurs |
| */ |
| public long skip(long count) throws IOException |
| { |
| if (in == null) |
| throw new IOException("Reader has been closed"); |
| |
| return super.skip(count); |
| } |
| } |