1 files changed, 156 insertions, 0 deletions
diff --git a/lib/antlr/src/TokenStreamHiddenTokenFilter.cpp b/lib/antlr/src/TokenStreamHiddenTokenFilter.cpp
new file mode 100644
index 00000000..431df0c3
--- /dev/null
+++ b/lib/antlr/src/TokenStreamHiddenTokenFilter.cpp
@@ -0,0 +1,156 @@
+/* ANTLR Translator Generator
+ * Project led by Terence Parr at http://www.jGuru.com
+ * Software rights: http://www.antlr.org/license.html
+ *
+ * $Id$
+ */
+#include "antlr/TokenStreamHiddenTokenFilter.hpp"
+#include "antlr/CommonHiddenStreamToken.hpp"
+
+#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
+namespace antlr {
+#endif
+
+/**This object filters a token stream coming from a lexer
+ * or another TokenStream so that only certain token channels
+ * get transmitted to the parser.
+ *
+ * Any of the channels can be filtered off as "hidden" channels whose
+ * tokens can be accessed from the parser.
+ */
+
+TokenStreamHiddenTokenFilter::TokenStreamHiddenTokenFilter(TokenStream& input)
+: TokenStreamBasicFilter(input)
+{
+}
+
+void TokenStreamHiddenTokenFilter::consume()
+{
+	nextMonitoredToken = input->nextToken();
+}
+
+void TokenStreamHiddenTokenFilter::consumeFirst()
+{
+	consume();
+
+	// Handle situation where hidden or discarded tokens
+	// appear first in input stream
+	RefToken p;
+	// while hidden or discarded scarf tokens
+	while ( hideMask.member(LA(1)->getType()) || discardMask.member(LA(1)->getType()) ) {
+		if ( hideMask.member(LA(1)->getType()) ) {
+			if ( !p ) {
+				p = LA(1);
+			}
+			else {
+				static_cast<CommonHiddenStreamToken*>(p.get())->setHiddenAfter(LA(1));
+				static_cast<CommonHiddenStreamToken*>(LA(1).get())->setHiddenBefore(p); // double-link
+				p = LA(1);
+			}
+			lastHiddenToken = p;
+			if (!firstHidden)
+				firstHidden = p; // record hidden token if first
+		}
+		consume();
+	}
+}
+
+BitSet TokenStreamHiddenTokenFilter::getDiscardMask() const
+{
+	return discardMask;
+}
+
+/** Return a ptr to the hidden token appearing immediately after
+ *  token t in the input stream.
+ */
+RefToken TokenStreamHiddenTokenFilter::getHiddenAfter(RefToken t)
+{
+	return static_cast<CommonHiddenStreamToken*>(t.get())->getHiddenAfter();
+}
+
+/** Return a ptr to the hidden token appearing immediately before
+ *  token t in the input stream.
+ */
+RefToken TokenStreamHiddenTokenFilter::getHiddenBefore(RefToken t)
+{
+	return static_cast<CommonHiddenStreamToken*>(t.get())->getHiddenBefore();
+}
+
+BitSet TokenStreamHiddenTokenFilter::getHideMask() const
+{
+	return hideMask;
+}
+
+/** Return the first hidden token if one appears
+ *  before any monitored token.
+ */
+RefToken TokenStreamHiddenTokenFilter::getInitialHiddenToken()
+{
+	return firstHidden;
+}
+
+void TokenStreamHiddenTokenFilter::hide(int m)
+{
+	hideMask.add(m);
+}
+
+void TokenStreamHiddenTokenFilter::hide(const BitSet& mask)
+{
+	hideMask = mask;
+}
+
+RefToken TokenStreamHiddenTokenFilter::LA(int)
+{
+	return nextMonitoredToken;
+}
+
+/** Return the next monitored token.
+*  Test the token following the monitored token.
+*  If following is another monitored token, save it
+*  for the next invocation of nextToken (like a single
+*  lookahead token) and return it then.
+*  If following is unmonitored, nondiscarded (hidden)
+*  channel token, add it to the monitored token.
+*
+*  Note: EOF must be a monitored Token.
+*/
+RefToken TokenStreamHiddenTokenFilter::nextToken()
+{
+	// handle an initial condition; don't want to get lookahead
+	// token of this splitter until first call to nextToken
+	if ( !LA(1) ) {
+		consumeFirst();
+	}
+
+	// we always consume hidden tokens after monitored, thus,
+	// upon entry LA(1) is a monitored token.
+	RefToken monitored = LA(1);
+	// point to hidden tokens found during last invocation
+	static_cast<CommonHiddenStreamToken*>(monitored.get())->setHiddenBefore(lastHiddenToken);
+	lastHiddenToken = nullToken;
+
+	// Look for hidden tokens, hook them into list emanating
+	// from the monitored tokens.
+	consume();
+	RefToken p = monitored;
+	// while hidden or discarded scarf tokens
+	while ( hideMask.member(LA(1)->getType()) || discardMask.member(LA(1)->getType()) ) {
+		if ( hideMask.member(LA(1)->getType()) ) {
+			// attach the hidden token to the monitored in a chain
+			// link forwards
+			static_cast<CommonHiddenStreamToken*>(p.get())->setHiddenAfter(LA(1));
+			// link backwards
+			if (p != monitored) { //hidden cannot point to monitored tokens
+				static_cast<CommonHiddenStreamToken*>(LA(1).get())->setHiddenBefore(p);
+			}
+			p = lastHiddenToken = LA(1);
+		}
+		consume();
+	}
+	return monitored;
+}
+
+#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
+}
+#endif
+