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