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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/java/io/InputStreamReader.java | |
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Diffstat (limited to 'libjava/classpath/java/io/InputStreamReader.java')
-rw-r--r-- | libjava/classpath/java/io/InputStreamReader.java | 509 |
1 files changed, 509 insertions, 0 deletions
diff --git a/libjava/classpath/java/io/InputStreamReader.java b/libjava/classpath/java/io/InputStreamReader.java new file mode 100644 index 000000000..51925a8c5 --- /dev/null +++ b/libjava/classpath/java/io/InputStreamReader.java @@ -0,0 +1,509 @@ +/* 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; + + /** + * A byte array to be reused in read(byte[], int, int). + */ + private byte[] bytesCache; + + /** + * Locks the bytesCache above in read(byte[], int, int). + */ + private Object cacheLock = new Object(); + + /** + * 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); + if (byteBuffer != null) + totalBytes = Math.max(totalBytes, byteBuffer.remaining()); + byte[] bytes; + // Fetch cached bytes array if available and big enough. + synchronized(cacheLock) + { + bytes = bytesCache; + if (bytes == null || bytes.length < totalBytes) + bytes = new byte[totalBytes]; + else + bytesCache = null; + } + + 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; + + // Put cached bytes array back if we are finished and the cache + // is null or smaller than the used bytes array. + synchronized (cacheLock) + { + if (byteBuffer == null + && (bytesCache == null || bytesCache.length < bytes.length)) + bytesCache = bytes; + } + return (read <= 0) ? -1 : read; + } + else + { + byte[] bytes; + // Fetch cached bytes array if available and big enough. + synchronized (cacheLock) + { + bytes = bytesCache; + if (bytes == null || length < bytes.length) + bytes = new byte[length]; + else + bytesCache = null; + } + + int read = in.read(bytes); + for(int i=0;i<read;i++) + buf[offset+i] = (char)(bytes[i]&0xFF); + + // Put back byte array into cache if appropriate. + synchronized (cacheLock) + { + if (bytesCache == null || bytesCache.length < bytes.length) + bytesCache = bytes; + } + 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); + } +} |