package antlr;
/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.cs.usfca.edu
* Software rights: http://www.antlr.org/license.html
*
* $Id: //depot/code/org.antlr/release/antlr-2.7.7/antlr/CharBuffer.java#2 $
*/
/**A Stream of characters fed to the lexer from a InputStream that can
* be rewound via mark()/rewind() methods.
* <p>
* A dynamic array is used to buffer up all the input characters. Normally,
* "k" characters are stored in the buffer. More characters may be stored during
* guess mode (testing syntactic predicate), or when LT(i>k) is referenced.
* Consumption of characters is deferred. In other words, reading the next
* character is not done by conume(), but deferred until needed by LA or LT.
* <p>
*
* @see antlr.CharQueue
*/
import java.io.
IOException;
import java.io.
Reader;
// SAS: Move most functionality into InputBuffer -- just the file-specific
// stuff is in here
public class
CharBuffer extends
InputBuffer {
// char source
public transient
Reader input;
/** Create a character buffer */
public
CharBuffer(
Reader input_) { // SAS: for proper text i/o
super();
input =
input_;
}
/** Ensure that the character buffer is sufficiently full */
public void
fill(int
amount) throws
CharStreamException {
try {
syncConsume();
// Fill the buffer sufficiently to hold needed characters
while (
queue.
nbrEntries <
amount +
markerOffset) {
// Append the next character
queue.
append((char)
input.
read());
}
}
catch (
IOException io) {
throw new
CharStreamIOException(
io);
}
}
}