#ifndef	ANTLR3REWRITESTREAM_HPP
#define	ANTLR3REWRITESTREAM_HPP

// [The "BSD licence"]
// Copyright (c) 2005-2009 Gokulakannan Somasundaram, ElectronDB

//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
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// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
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// 3. The name of the author may not be used to endorse or promote products
//    derived from this software without specific prior written permission.
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namespace antlr3 {

/// This is an implementation of a token stream, which is basically an element
///  stream that deals with tokens only.
///
template<class ImplTraits>
class RewriteRuleTokenStream
{
public:
	typedef typename ImplTraits::StringType StringType;
	typedef typename ImplTraits::AllocPolicyType AllocPolicyType;
	typedef typename ImplTraits::TreeAdaptorType TreeAdaptorType;
	typedef typename ImplTraits::ParserType ComponentType;
	typedef typename ComponentType::StreamType StreamType;
	typedef typename ImplTraits::CommonTokenType TokenType;
	typedef typename ImplTraits::TreeType TreeType;
	typedef typename ImplTraits::TreeTypePtr TreeTypePtr;
	typedef typename AllocPolicyType::template VectorType<const TokenType* > ElementsType;
	typedef typename ImplTraits::template RecognizerType< StreamType > RecognizerType;
	typedef typename ImplTraits::CommonTokenType ElementType;
public:
	RewriteRuleTokenStream(TreeAdaptorType* adaptor, const char* description);
	RewriteRuleTokenStream(TreeAdaptorType* adaptor, const char* description, const TokenType* oneElement);
	RewriteRuleTokenStream(TreeAdaptorType* adaptor, const char* description, const ElementsType& elements);
	~RewriteRuleTokenStream();

    /// Reset the condition of this stream so that it appears we have
    ///  not consumed any of its elements.  Elements themselves are untouched.
    ///
    void	reset();

	TreeTypePtr	nextNode();
	const TokenType*  nextToken();

	/// TODO copied from RewriteRuleElementStreamType
    /// Add a new pANTLR3_BASE_TREE to this stream
    ///
    void	add(const ElementType* el);

	/// When constructing trees, sometimes we need to dup a token or AST
    ///	subtree.  Dup'ing a token means just creating another AST node
    /// around it.  For trees, you must call the adaptor.dupTree().
    ///
	ElementType* dup( ElementType* el );

    /// Ensure stream emits trees; tokens must be converted to AST nodes.
    /// AST nodes can be passed through unmolested.
    ///
    TreeTypePtr toTree(const ElementType* el);

	/// Pointer to the tree adaptor in use for this stream
	///
    TreeAdaptorType*	m_adaptor;
    ElementType nextTree();
	typename ElementsType::iterator _next();

    /// Returns true if there is a next element available
    ///
    bool	hasNext();

    /// Number of elements available in the stream
    ///
    ANTLR_UINT32	size();

    /// Returns the description string if there is one available (check for NULL).
    ///
    StringType getDescription();

private:
	ElementType* dupImpl(typename ImplTraits::CommonTokenType* el);
	ElementType* dupImpl(typename ImplTraits::TreeTypePtr el);

	/// Cursor 0..n-1.  If singleElement!=NULL, cursor is 0 until you next(),
    /// which bumps it to 1 meaning no more elements.
    ///
	typename ElementsType::iterator m_cursor;

    /// The element or stream description; usually has name of the token or
    /// rule reference that this list tracks.  Can include rulename too, but
    /// the exception would track that info.
    ///
    StringType		m_elementDescription;

    /// The list of tokens or subtrees we are tracking
    ///
    ElementsType		m_elements;

	/// Once a node / subtree has been used in a stream, it must be dup'ed
	/// from then on.  Streams are reset after sub rules so that the streams
	/// can be reused in future sub rules.  So, reset must set a dirty bit.
	/// If dirty, then next() always returns a dup.
	///
	bool m_dirty;
};

}

#include "antlr3rewriteruletokenstream.inl"

#endif