diff options
Diffstat (limited to 'src/org/apache/commons/net/io/FromNetASCIIInputStream.java')
| -rw-r--r-- | src/org/apache/commons/net/io/FromNetASCIIInputStream.java | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/src/org/apache/commons/net/io/FromNetASCIIInputStream.java b/src/org/apache/commons/net/io/FromNetASCIIInputStream.java new file mode 100644 index 0000000..76588ab --- /dev/null +++ b/src/org/apache/commons/net/io/FromNetASCIIInputStream.java @@ -0,0 +1,205 @@ +/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.net.io;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.PushbackInputStream;
+
+/***
+ * This class wraps an input stream, replacing all occurrences
+ * of <CR><LF> (carriage return followed by a linefeed),
+ * which is the NETASCII standard for representing a newline, with the
+ * local line separator representation. You would use this class to
+ * implement ASCII file transfers requiring conversion from NETASCII.
+ * <p>
+ * <p>
+ * @author Daniel F. Savarese
+ ***/
+
+public final class FromNetASCIIInputStream extends PushbackInputStream
+{
+ static final boolean _noConversionRequired;
+ static final String _lineSeparator;
+ static final byte[] _lineSeparatorBytes;
+
+ static {
+ _lineSeparator = System.getProperty("line.separator");
+ _noConversionRequired = _lineSeparator.equals("\r\n");
+ _lineSeparatorBytes = _lineSeparator.getBytes();
+ }
+
+ private int __length = 0;
+
+ /***
+ * Returns true if the NetASCII line separator differs from the system
+ * line separator, false if they are the same. This method is useful
+ * to determine whether or not you need to instantiate a
+ * FromNetASCIIInputStream object.
+ * <p>
+ * @return True if the NETASCII line separator differs from the local
+ * system line separator, false if they are the same.
+ ***/
+ public static final boolean isConversionRequired()
+ {
+ return !_noConversionRequired;
+ }
+
+ /***
+ * Creates a FromNetASCIIInputStream instance that wraps an existing
+ * InputStream.
+ ***/
+ public FromNetASCIIInputStream(InputStream input)
+ {
+ super(input, _lineSeparatorBytes.length + 1);
+ }
+
+
+ private int __read() throws IOException
+ {
+ int ch;
+
+ ch = super.read();
+
+ if (ch == '\r')
+ {
+ ch = super.read();
+ if (ch == '\n')
+ {
+ unread(_lineSeparatorBytes);
+ ch = super.read();
+ // This is a kluge for read(byte[], ...) to read the right amount
+ --__length;
+ }
+ else
+ {
+ if (ch != -1)
+ unread(ch);
+ return '\r';
+ }
+ }
+
+ return ch;
+ }
+
+
+ /***
+ * Reads and returns the next byte in the stream. If the end of the
+ * message has been reached, returns -1. Note that a call to this method
+ * may result in multiple reads from the underlying input stream in order
+ * to convert NETASCII line separators to the local line separator format.
+ * This is transparent to the programmer and is only mentioned for
+ * completeness.
+ * <p>
+ * @return The next character in the stream. Returns -1 if the end of the
+ * stream has been reached.
+ * @exception IOException If an error occurs while reading the underlying
+ * stream.
+ ***/
+ @Override
+ public int read() throws IOException
+ {
+ if (_noConversionRequired)
+ return super.read();
+
+ return __read();
+ }
+
+
+ /***
+ * Reads the next number of bytes from the stream into an array and
+ * returns the number of bytes read. Returns -1 if the end of the
+ * stream has been reached.
+ * <p>
+ * @param buffer The byte array in which to store the data.
+ * @return The number of bytes read. Returns -1 if the
+ * end of the message has been reached.
+ * @exception IOException If an error occurs in reading the underlying
+ * stream.
+ ***/
+ @Override
+ public int read(byte buffer[]) throws IOException
+ {
+ return read(buffer, 0, buffer.length);
+ }
+
+
+ /***
+ * Reads the next number of bytes from the stream into an array and returns
+ * the number of bytes read. Returns -1 if the end of the
+ * message has been reached. The characters are stored in the array
+ * starting from the given offset and up to the length specified.
+ * <p>
+ * @param buffer The byte array in which to store the data.
+ * @param offset The offset into the array at which to start storing data.
+ * @param length The number of bytes to read.
+ * @return The number of bytes read. Returns -1 if the
+ * end of the stream has been reached.
+ * @exception IOException If an error occurs while reading the underlying
+ * stream.
+ ***/
+ @Override
+ public int read(byte buffer[], int offset, int length) throws IOException
+ {
+ int ch, off;
+
+ if (length < 1)
+ return 0;
+
+ ch = available();
+
+ __length = (length > ch ? ch : length);
+
+ // If nothing is available, block to read only one character
+ if (__length < 1)
+ __length = 1;
+
+ if (_noConversionRequired)
+ return super.read(buffer, offset, __length);
+
+ if ((ch = __read()) == -1)
+ return -1;
+
+ off = offset;
+
+ do
+ {
+ buffer[offset++] = (byte)ch;
+ }
+ while (--__length > 0 && (ch = __read()) != -1);
+
+
+ return (offset - off);
+ }
+
+
+ // PushbackInputStream in JDK 1.1.3 returns the wrong thing
+ /***
+ * Returns the number of bytes that can be read without blocking EXCEPT
+ * when newline conversions have to be made somewhere within the
+ * available block of bytes. In other words, you really should not
+ * rely on the value returned by this method if you are trying to avoid
+ * blocking.
+ ***/
+ @Override
+ public int available() throws IOException
+ {
+ return (buf.length - pos) + in.available();
+ }
+
+}
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