1 files changed, 146 insertions, 0 deletions
diff --git a/lib/antlr/antlr/InputBuffer.h b/lib/antlr/antlr/InputBuffer.h
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+++ b/lib/antlr/antlr/InputBuffer.h
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+#ifndef INC_InputBuffer_h__
+#define INC_InputBuffer_h__
+
+/* ANTLR Translator Generator
+ * Project led by Terence Parr at http://www.jGuru.com
+ * Software rights: http://www.antlr.org/license.html
+ *
+ * $Id$
+ */
+
+#include <antlr/config.h>
+#include <antlr/CircularQueue.h>
+#include <string>
+
+#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
+namespace antlr {
+#endif
+
+/** 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
+ */
+class ANTLR_API InputBuffer {
+public:
+	/** Create a character buffer */
+	InputBuffer()
+	: nMarkers(0)
+	, markerOffset(0)
+	, numToConsume(0)
+	{
+	}
+
+	virtual ~InputBuffer()
+	{
+	}
+
+	/// Reset the input buffer to empty state
+	virtual inline void reset( void )
+	{
+		nMarkers = 0;
+		markerOffset = 0;
+		numToConsume = 0;
+		queue.clear();
+	}
+
+	/** This method updates the state of the input buffer so that
+	 * the text matched since the most recent mark() is no longer
+	 * held by the buffer.  So, you either do a mark/rewind for
+	 * failed predicate or mark/commit to keep on parsing without
+	 * rewinding the input.
+	 */
+	inline void commit( void )
+	{
+		nMarkers--;
+	}
+
+	/** Mark another character for deferred consumption */
+	virtual inline void consume()
+	{
+		numToConsume++;
+	}
+
+	/** Ensure that the character buffer is sufficiently full */
+	virtual void fill(unsigned int amount);
+
+	/** Override this in subclasses to get the next character */
+	virtual int getChar()=0;
+
+	/** Get a lookahead character */
+	virtual inline int LA(unsigned int i)
+	{
+		fill(i);
+		return queue.elementAt(markerOffset + i - 1);
+	}
+
+	/** Return an integer marker that can be used to rewind the buffer to
+	 * its current state.
+	 */
+	virtual unsigned int mark();
+	/// Are there any marks active in the InputBuffer
+	virtual inline bool isMarked() const
+	{
+		return (nMarkers != 0);
+	}
+	/** Rewind the character buffer to a marker.
+	 * @param mark Marker returned previously from mark()
+	 */
+	virtual void rewind(unsigned int mark);
+
+	/** Get the number of non-consumed characters
+	 */
+	virtual unsigned int entries() const;
+
+	ANTLR_USE_NAMESPACE(std)string getLAChars() const;
+
+	ANTLR_USE_NAMESPACE(std)string getMarkedChars() const;
+
+protected:
+	// char source
+	// leave to subclasses
+
+	// Number of active markers
+	unsigned int nMarkers; // = 0;
+
+	// Additional offset used when markers are active
+	unsigned int markerOffset; // = 0;
+
+	// Number of calls to consume() since last LA() or LT() call
+	unsigned int numToConsume; // = 0;
+
+	// Circular queue
+	CircularQueue<int> queue;
+
+	/** Sync up deferred consumption */
+	void syncConsume();
+
+private:
+	InputBuffer(const InputBuffer& other);
+	InputBuffer& operator=(const InputBuffer& other);
+};
+
+/** Sync up deferred consumption */
+inline void InputBuffer::syncConsume() {
+	if (numToConsume > 0)
+	{
+		if (nMarkers > 0)
+			markerOffset += numToConsume;
+		else
+			queue.removeItems( numToConsume );
+		numToConsume = 0;
+	}
+}
+
+#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
+}
+#endif
+
+#endif //INC_InputBuffer_h__