| /* |
| * Copyright 1999,2004 The Apache Software Foundation. |
| * |
| * Licensed 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.jasper.xmlparser; |
| |
| import java.io.InputStream; |
| import java.io.IOException; |
| import java.io.Reader; |
| import org.apache.jasper.compiler.Localizer; |
| |
| /** |
| * A simple ASCII byte reader. This is an optimized reader for reading |
| * byte streams that only contain 7-bit ASCII characters. |
| * |
| * @author Andy Clark, IBM |
| * |
| * @version $Id$ |
| */ |
| public class ASCIIReader |
| extends Reader { |
| |
| // |
| // Constants |
| // |
| |
| /** Default byte buffer size (2048). */ |
| public static final int DEFAULT_BUFFER_SIZE = 2048; |
| |
| // |
| // Data |
| // |
| |
| /** Input stream. */ |
| protected InputStream fInputStream; |
| |
| /** Byte buffer. */ |
| protected byte[] fBuffer; |
| |
| // |
| // Constructors |
| // |
| |
| /** |
| * Constructs an ASCII reader from the specified input stream |
| * and buffer size. |
| * |
| * @param inputStream The input stream. |
| * @param size The initial buffer size. |
| */ |
| public ASCIIReader(InputStream inputStream, int size) { |
| fInputStream = inputStream; |
| fBuffer = new byte[size]; |
| } |
| |
| // |
| // Reader methods |
| // |
| |
| /** |
| * Read a single character. This method will block until a character is |
| * available, an I/O error occurs, or the end of the stream is reached. |
| * |
| * <p> Subclasses that intend to support efficient single-character input |
| * should override this method. |
| * |
| * @return The character read, as an integer in the range 0 to 127 |
| * (<tt>0x00-0x7f</tt>), or -1 if the end of the stream has |
| * been reached |
| * |
| * @exception IOException If an I/O error occurs |
| */ |
| public int read() throws IOException { |
| int b0 = fInputStream.read(); |
| if (b0 > 0x80) { |
| throw new IOException(Localizer.getMessage("jsp.error.xml.invalidASCII", |
| Integer.toString(b0))); |
| } |
| return b0; |
| } // read():int |
| |
| /** |
| * Read characters into a portion of an array. This method will block |
| * until some input is available, an I/O error occurs, or the end of the |
| * stream is reached. |
| * |
| * @param ch Destination buffer |
| * @param offset Offset at which to start storing characters |
| * @param length Maximum number of characters to read |
| * |
| * @return The number of characters read, or -1 if the end of the |
| * stream has been reached |
| * |
| * @exception IOException If an I/O error occurs |
| */ |
| public int read(char ch[], int offset, int length) throws IOException { |
| if (length > fBuffer.length) { |
| length = fBuffer.length; |
| } |
| int count = fInputStream.read(fBuffer, 0, length); |
| for (int i = 0; i < count; i++) { |
| int b0 = fBuffer[i]; |
| if (b0 > 0x80) { |
| throw new IOException(Localizer.getMessage("jsp.error.xml.invalidASCII", |
| Integer.toString(b0))); |
| } |
| ch[offset + i] = (char)b0; |
| } |
| return count; |
| } // read(char[],int,int) |
| |
| /** |
| * Skip characters. This method will block until some characters are |
| * available, an I/O error occurs, or the end of the stream is reached. |
| * |
| * @param n The number of characters to skip |
| * |
| * @return The number of characters actually skipped |
| * |
| * @exception IOException If an I/O error occurs |
| */ |
| public long skip(long n) throws IOException { |
| return fInputStream.skip(n); |
| } // skip(long):long |
| |
| /** |
| * Tell whether this stream is ready to be read. |
| * |
| * @return True if the next read() is guaranteed not to block for input, |
| * false otherwise. Note that returning false does not guarantee that the |
| * next read will block. |
| * |
| * @exception IOException If an I/O error occurs |
| */ |
| public boolean ready() throws IOException { |
| return false; |
| } // ready() |
| |
| /** |
| * Tell whether this stream supports the mark() operation. |
| */ |
| public boolean markSupported() { |
| return fInputStream.markSupported(); |
| } // markSupported() |
| |
| /** |
| * Mark the present position in the stream. Subsequent calls to reset() |
| * will attempt to reposition the stream to this point. Not all |
| * character-input streams support the mark() operation. |
| * |
| * @param readAheadLimit Limit on the number of characters that may be |
| * read while still preserving the mark. After |
| * reading this many characters, attempting to |
| * reset the stream may fail. |
| * |
| * @exception IOException If the stream does not support mark(), |
| * or if some other I/O error occurs |
| */ |
| public void mark(int readAheadLimit) throws IOException { |
| fInputStream.mark(readAheadLimit); |
| } // mark(int) |
| |
| /** |
| * Reset the stream. If the stream has been marked, then attempt to |
| * reposition it at the mark. If the stream has not been marked, then |
| * attempt to reset it in some way appropriate to the particular stream, |
| * for example by repositioning it to its starting point. Not all |
| * character-input streams support the reset() operation, and some support |
| * reset() without supporting mark(). |
| * |
| * @exception IOException If the stream has not been marked, |
| * or if the mark has been invalidated, |
| * or if the stream does not support reset(), |
| * or if some other I/O error occurs |
| */ |
| public void reset() throws IOException { |
| fInputStream.reset(); |
| } // reset() |
| |
| /** |
| * Close the stream. Once a stream has been closed, further read(), |
| * ready(), mark(), or reset() invocations will throw an IOException. |
| * Closing a previously-closed stream, however, has no effect. |
| * |
| * @exception IOException If an I/O error occurs |
| */ |
| public void close() throws IOException { |
| fInputStream.close(); |
| } // close() |
| |
| } // class ASCIIReader |