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;
}
}