package org.caudexorigo.io;
import java.io.IOException;
import java.io.Reader;
public class UnsynchronizedBufferedReader extends Reader
{
private Reader in;
private char cb[];
private int nChars, nextChar;
private static final int INVALIDATED = -2;
private static final int UNMARKED = -1;
private int markedChar = UNMARKED;
private int readAheadLimit = 0; /* Valid only when markedChar > 0 */
/** If the next character is a line feed, skip it */
private boolean skipLF = false;
/** The skipLF flag when the mark was set */
private boolean markedSkipLF = false;
private static int defaultCharBufferSize = 8192;
private static int defaultExpectedLineLength = 80;
/**
* Creates a buffering character-input stream that uses an input buffer of the
* specified size.
*
* @param in
* A Reader
* @param sz
* Input-buffer size
*
* @exception IllegalArgumentException
* If sz is <= 0
*/
public UnsynchronizedBufferedReader(Reader in, int sz)
{
super(in);
if (sz <= 0)
throw new IllegalArgumentException("Buffer size <= 0");
this.in = in;
cb = new char[sz];
nextChar = nChars = 0;
}
/**
* Creates a buffering character-input stream that uses a default-sized input
* buffer.
*
* @param in
* A Reader
*/
public UnsynchronizedBufferedReader(Reader in)
{
this(in, defaultCharBufferSize);
}
/** Checks to make sure that the stream has not been closed */
private void ensureOpen() throws IOException
{
if (in == null)
throw new IOException("Stream closed");
}
/**
* Fills the input buffer, taking the mark into account if it is valid.
*/
private void fill() throws IOException
{
int dst;
if (markedChar <= UNMARKED)
{
/* No mark */
dst = 0;
}
else
{
/* Marked */
int delta = nextChar - markedChar;
if (delta >= readAheadLimit)
{
/* Gone past read-ahead limit: Invalidate mark */
markedChar = INVALIDATED;
readAheadLimit = 0;
dst = 0;
}
else
{
if (readAheadLimit <= cb.length)
{
/* Shuffle in the current buffer */
System.arraycopy(cb, markedChar, cb, 0, delta);
markedChar = 0;
dst = delta;
}
else
{
/* Reallocate buffer to accommodate read-ahead limit */
char ncb[] = new char[readAheadLimit];
System.arraycopy(cb, markedChar, ncb, 0, delta);
cb = ncb;
markedChar = 0;
dst = delta;
}
nextChar = nChars = delta;
}
}
int n;
do
{
n = in.read(cb, dst, cb.length - dst);
}
while (n == 0);
if (n > 0)
{
nChars = dst + n;
nextChar = dst;
}
}
/**
* Reads a single character.
*
* @return The character read, as an integer in the range 0 to 65535 (
* <tt>0x00-0xffff</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
{
ensureOpen();
for (;;)
{
if (nextChar >= nChars)
{
fill();
if (nextChar >= nChars)
return -1;
}
if (skipLF)
{
skipLF = false;
if (cb[nextChar] == '\n')
{
nextChar++;
continue;
}
}
return cb[nextChar++];
}
}
/**
* Reads characters into a portion of an array, reading from the underlying
* stream if necessary.
*/
private int read1(char[] cbuf, int off, int len) throws IOException
{
if (nextChar >= nChars)
{
/*
* If the requested length is at least as large as the buffer, and if
* there is no mark/reset activity, and if line feeds are not being
* skipped, do not bother to copy the characters into the local buffer.
* In this way buffered streams will cascade harmlessly.
*/
if (len >= cb.length && markedChar <= UNMARKED && !skipLF)
{
return in.read(cbuf, off, len);
}
fill();
}
if (nextChar >= nChars)
return -1;
if (skipLF)
{
skipLF = false;
if (cb[nextChar] == '\n')
{
nextChar++;
if (nextChar >= nChars)
fill();
if (nextChar >= nChars)
return -1;
}
}
int n = Math.min(len, nChars - nextChar);
System.arraycopy(cb, nextChar, cbuf, off, n);
nextChar += n;
return n;
}
/**
* Reads characters into a portion of an array.
*
* <p>
* This method implements the general contract of the corresponding
* <code>{@link Reader#read(char[], int, int) read}</code> method of the
* <code>{@link Reader}</code> class. As an additional convenience, it attempts
* to read as many characters as possible by repeatedly invoking the
* <code>read</code> method of the underlying stream. This iterated
* <code>read</code> continues until one of the following conditions becomes
* true:
* <ul>
*
* <li>The specified number of characters have been read,
*
* <li>The <code>read</code> method of the underlying stream returns
* <code>-1</code>, indicating end-of-file, or
*
* <li>The <code>ready</code> method of the underlying stream returns
* <code>false</code>, indicating that further input requests would block.
*
* </ul>
* If the first <code>read</code> on the underlying stream returns
* <code>-1</code> to indicate end-of-file then this method returns
* <code>-1</code>. Otherwise this method returns the number of characters
* actually read.
*
* <p>
* Subclasses of this class are encouraged, but not required, to attempt to read
* as many characters as possible in the same fashion.
*
* <p>
* Ordinarily this method takes characters from this stream's character buffer,
* filling it from the underlying stream as necessary. If, however, the buffer is
* empty, the mark is not valid, and the requested length is at least as large as
* the buffer, then this method will read characters directly from the underlying
* stream into the given array. Thus redundant <code>BufferedReader</code>s will
* not copy data unnecessarily.
*
* @param cbuf
* Destination buffer
* @param off
* Offset at which to start storing characters
* @param len
* 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 cbuf[], int off, int len) throws IOException
{
ensureOpen();
if ((off < 0) || (off > cbuf.length) || (len < 0) || ((off + len) > cbuf.length) || ((off + len) < 0))
{
throw new IndexOutOfBoundsException();
}
else if (len == 0)
{
return 0;
}
int n = read1(cbuf, off, len);
if (n <= 0)
return n;
while ((n < len) && in.ready())
{
int n1 = read1(cbuf, off + n, len - n);
if (n1 <= 0)
break;
n += n1;
}
return n;
}
/**
* Reads a line of text. A line is considered to be terminated by any one of a
* line feed ('\n'), a carriage return ('\r'), or a carriage return followed
* immediately by a linefeed.
*
* @param ignoreLF
* If true, the next '\n' will be skipped
*
* @return A String containing the contents of the line, not including any
* line-termination characters, or null if the end of the stream has been
* reached
*
* @see java.io.LineNumberReader#readLine()
*
* @exception IOException
* If an I/O error occurs
*/
String readLine(boolean ignoreLF) throws IOException
{
StringBuffer s = null;
int startChar;
ensureOpen();
boolean omitLF = ignoreLF || skipLF;
bufferLoop: for (;;)
{
if (nextChar >= nChars)
fill();
if (nextChar >= nChars)
{ /* EOF */
if (s != null && s.length() > 0)
return s.toString();
else
return null;
}
boolean eol = false;
char c = 0;
int i;
/* Skip a leftover '\n', if necessary */
if (omitLF && (cb[nextChar] == '\n'))
nextChar++;
skipLF = false;
omitLF = false;
charLoop: for (i = nextChar; i < nChars; i++)
{
c = cb[i];
if ((c == '\n') || (c == '\r'))
{
eol = true;
break charLoop;
}
}
startChar = nextChar;
nextChar = i;
if (eol)
{
String str;
if (s == null)
{
str = new String(cb, startChar, i - startChar);
}
else
{
s.append(cb, startChar, i - startChar);
str = s.toString();
}
nextChar++;
if (c == '\r')
{
skipLF = true;
}
return str;
}
if (s == null)
s = new StringBuffer(defaultExpectedLineLength);
s.append(cb, startChar, i - startChar);
}
}
/**
* Reads a line of text. A line is considered to be terminated by any one of a
* line feed ('\n'), a carriage return ('\r'), or a carriage return followed
* immediately by a linefeed.
*
* @return A String containing the contents of the line, not including any
* line-termination characters, or null if the end of the stream has been
* reached
*
* @exception IOException
* If an I/O error occurs
*/
public String readLine() throws IOException
{
return readLine(false);
}
/**
* Skips characters.
*
* @param n
* The number of characters to skip
*
* @return The number of characters actually skipped
*
* @exception IllegalArgumentException
* If <code>n</code> is negative.
* @exception IOException
* If an I/O error occurs
*/
public long skip(long n) throws IOException
{
if (n < 0L)
{
throw new IllegalArgumentException("skip value is negative");
}
ensureOpen();
long r = n;
while (r > 0)
{
if (nextChar >= nChars)
fill();
if (nextChar >= nChars) /* EOF */
break;
if (skipLF)
{
skipLF = false;
if (cb[nextChar] == '\n')
{
nextChar++;
}
}
long d = nChars - nextChar;
if (r <= d)
{
nextChar += r;
r = 0;
break;
}
else
{
r -= d;
nextChar = nChars;
}
}
return n - r;
}
/**
* Tells whether this stream is ready to be read. A buffered character stream is
* ready if the buffer is not empty, or if the underlying character stream is
* ready.
*
* @exception IOException
* If an I/O error occurs
*/
public boolean ready() throws IOException
{
ensureOpen();
/*
* If newline needs to be skipped and the next char to be read is a newline
* character, then just skip it right away.
*/
if (skipLF)
{
/*
* Note that in.ready() will return true if and only if the next read on
* the stream will not block.
*/
if (nextChar >= nChars && in.ready())
{
fill();
}
if (nextChar < nChars)
{
if (cb[nextChar] == '\n')
nextChar++;
skipLF = false;
}
}
return (nextChar < nChars) || in.ready();
}
/**
* Tells whether this stream supports the mark() operation, which it does.
*/
public boolean markSupported()
{
return true;
}
/**
* Marks the present position in the stream. Subsequent calls to reset() will
* attempt to reposition the stream to this point.
*
* @param readAheadLimit
* Limit on the number of characters that may be read while still
* preserving the mark. An attempt to reset the stream after reading
* characters up to this limit or beyond may fail. A limit value
* larger than the size of the input buffer will cause a new buffer to
* be allocated whose size is no smaller than limit. Therefore large
* values should be used with care.
*
* @exception IllegalArgumentException
* If readAheadLimit is < 0
* @exception IOException
* If an I/O error occurs
*/
public void mark(int readAheadLimit) throws IOException
{
if (readAheadLimit < 0)
{
throw new IllegalArgumentException("Read-ahead limit < 0");
}
ensureOpen();
this.readAheadLimit = readAheadLimit;
markedChar = nextChar;
markedSkipLF = skipLF;
}
/**
* Resets the stream to the most recent mark.
*
* @exception IOException
* If the stream has never been marked, or if the mark has been
* invalidated
*/
public void reset() throws IOException
{
ensureOpen();
if (markedChar < 0)
throw new IOException((markedChar == INVALIDATED) ? "Mark invalid" : "Stream not marked");
nextChar = markedChar;
skipLF = markedSkipLF;
}
public void close() throws IOException
{
if (in == null)
return;
in.close();
in = null;
cb = null;
}
}