Flee

Parsing/Matcher.cs

@@ -0,0 +1,107 @@
+namespace Flee.Parsing
+{
+    /**
+     * A regular expression string matcher. This class handles the
+     * matching of a specific string with a specific regular
+     * expression. It contains state information about the matching
+     * process, as for example the position of the latest match, and a
+     * number of flags that were set. This class is not thread-safe.
+     */
+    internal class Matcher
+    {
+        private readonly Element _element;
+        private ReaderBuffer _buffer;
+        private readonly bool _ignoreCase;
+        private int _start;
+        private int _length;
+        private bool _endOfString;
+
+        internal Matcher(Element e, ReaderBuffer buffer, bool ignoreCase)
+        {
+            this._element = e;
+            this._buffer = buffer;
+            this._ignoreCase = ignoreCase;
+            this._start = 0;
+            Reset();
+        }
+
+        public bool IsCaseInsensitive()
+        {
+            return _ignoreCase;
+        }
+
+        public void Reset()
+        {
+            _length = -1;
+            _endOfString = false;
+        }
+
+        public void Reset(string str)
+        {
+            Reset(new ReaderBuffer(new StringReader(str)));
+        }
+
+        public void Reset(ReaderBuffer buffer)
+        {
+            this._buffer = buffer;
+            Reset();
+        }
+
+        public int Start()
+        {
+            return _start;
+        }
+
+        public int End()
+        {
+            if (_length > 0)
+            {
+                return _start + _length;
+            }
+            else
+            {
+                return _start;
+            }
+        }
+
+        public int Length()
+        {
+            return _length;
+        }
+
+        public bool HasReadEndOfString()
+        {
+            return _endOfString;
+        }
+
+        public bool MatchFromBeginning()
+        {
+            return MatchFrom(0);
+        }
+
+        public bool MatchFrom(int pos)
+        {
+            Reset();
+            _start = pos;
+            _length = _element.Match(this, _buffer, _start, 0);
+            return _length >= 0;
+        }
+
+        public override string ToString()
+        {
+            if (_length <= 0)
+            {
+                return "";
+            }
+            else
+            {
+                return _buffer.Substring(_buffer.Position, _length);
+            }
+        }
+
+        internal void SetReadEndOfString()
+        {
+            _endOfString = true;
+        }
+    }
+}