Security-55471.tar.gz

[apple/security.git] / libsecurity_codesigning / antlr2 / src / TokenBuffer.cpp

diff --git a/libsecurity_codesigning/antlr2/src/TokenBuffer.cpp b/libsecurity_codesigning/antlr2/src/TokenBuffer.cpp
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+/* ANTLR Translator Generator
+ * Project led by Terence Parr at http://www.jGuru.com
+ * Software rights: http://www.antlr.org/license.html
+ *
+ * $Id: //depot/code/org.antlr/release/antlr-2.7.7/lib/cpp/src/TokenBuffer.cpp#2 $
+ */
+
+#include "antlr/TokenBuffer.hpp"
+
+#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
+namespace antlr {
+#endif
+
+/**A Stream of Token objects fed to the parser from a TokenStream that can
+ * be rewound via mark()/rewind() methods.
+ * <p>
+ * A dynamic array is used to buffer up all the input tokens.  Normally,
+ * "k" tokens are stored in the buffer.  More tokens may be stored during
+ * guess mode (testing syntactic predicate), or when LT(i>k) is referenced.
+ * Consumption of tokens is deferred.  In other words, reading the next
+ * token is not done by conume(), but deferred until needed by LA or LT.
+ * <p>
+ *
+ * @see antlr.Token
+ * @see antlr.TokenStream
+ * @see antlr.TokenQueue
+ */
+
+/** Create a token buffer */
+TokenBuffer::TokenBuffer( TokenStream& inp )
+: input(inp)
+, nMarkers(0)
+, markerOffset(0)
+, numToConsume(0)
+{
+}
+
+TokenBuffer::~TokenBuffer( void )
+{
+}
+
+/** Ensure that the token buffer is sufficiently full */
+void TokenBuffer::fill(unsigned int amount)
+{
+       syncConsume();
+       // Fill the buffer sufficiently to hold needed tokens
+       while (queue.entries() < (amount + markerOffset))
+       {
+               // Append the next token
+               queue.append(input.nextToken());
+       }
+}
+
+/** Get a lookahead token value */
+int TokenBuffer::LA(unsigned int i)
+{
+       fill(i);
+       return queue.elementAt(markerOffset+i-1)->getType();
+}
+
+/** Get a lookahead token */
+RefToken TokenBuffer::LT(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.
+ */
+unsigned int TokenBuffer::mark()
+{
+       syncConsume();
+       nMarkers++;
+       return markerOffset;
+}
+
+/**Rewind the token buffer to a marker.
+ * @param mark Marker returned previously from mark()
+ */
+void TokenBuffer::rewind(unsigned int mark)
+{
+       syncConsume();
+       markerOffset=mark;
+       nMarkers--;
+}
+
+/// Get number of non-consumed tokens
+unsigned int TokenBuffer::entries() const
+{
+       return (unsigned int)queue.entries() - markerOffset;
+}
+
+#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
+       }
+#endif