2003/06/28 06:54:18

[org.ibex.core.git] / src / gnu / regexp / RETokenLookAhead.java

diff --git a/src/gnu/regexp/RETokenLookAhead.java b/src/gnu/regexp/RETokenLookAhead.java
new file mode 100644 (file)
index 0000000..74a9bfe
--- /dev/null
+++ b/src/gnu/regexp/RETokenLookAhead.java
@@ -0,0 +1,68 @@
+/*
+ *  gnu/regexp/RETokenOneOf.java
+ *  Copyright (C) 1998-2001 Wes Biggs
+ *
+ *  This library is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published
+ *  by the Free Software Foundation; either version 2.1 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+package gnu.regexp;
+
+/**
+ * @since gnu.regexp 1.1.3
+ * @author Shashank Bapat
+ */
+final class RETokenLookAhead extends REToken
+{
+  REToken re;
+  boolean negative;
+
+  RETokenLookAhead(REToken re, boolean negative) throws REException {
+    super(0);
+    this.re = re;
+    this.negative = negative;
+  }
+
+  boolean match(CharIndexed input, REMatch mymatch)
+  {
+    REMatch trymatch = (REMatch)mymatch.clone();
+    REMatch trymatch1 = (REMatch)mymatch.clone();
+    REMatch newMatch = null;
+    if (re.match(input, trymatch)) {
+      if (negative) return false;
+      if (next(input, trymatch1))
+        newMatch = trymatch1;
+    }
+
+    if (newMatch != null) {
+      if (negative) return false;
+      //else
+      mymatch.assignFrom(newMatch);
+      return true;
+    }
+    else { // no match
+      if (negative)
+        return next(input, mymatch);
+      //else
+      return false;
+    }
+  }
+
+    void dump(StringBuffer os) {
+       os.append("(?");
+       os.append(negative ? '!' : '=');
+       re.dumpAll(os);
+       os.append(')');
+    }
+}
+