Antlr4.Runtime.UnbufferedTokenStream.Release C# (CSharp) Method

        public virtual void Release(int marker)
        {
            int expectedMark = -numMarkers;
            if (marker != expectedMark)
            {
                throw new InvalidOperationException("release() called with an invalid marker.");
            }
            numMarkers--;
            if (numMarkers == 0)
            {
                // can we release buffer?
                if (p > 0)
                {
                    // Copy tokens[p]..tokens[n-1] to tokens[0]..tokens[(n-1)-p], reset ptrs
                    // p is last valid token; move nothing if p==n as we have no valid char
                    System.Array.Copy(tokens, p, tokens, 0, n - p);
                    // shift n-p tokens from p to 0
                    n = n - p;
                    p = 0;
                }
                lastTokenBufferStart = lastToken;
            }
        }