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根据cs源码解析为codedom

/*----------------------------------------------------------------------
Compiler Generator Coco/R,
Copyright (c) 1990, 2004 Hanspeter Moessenboeck, University of Linz
extended by M. Loeberbauer & A. Woess, Univ. of Linz
with improvements by Pat Terry, Rhodes University

This program is free software; you can redistribute it and/or modify it 
under the terms of the GNU General Public License as published by the 
Free Software Foundation; either version 2, or (at your option) any 
later version.

This program 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 General Public License 
for more details.

You should have received a copy of the GNU General Public License along 
with this program; if not, write to the Free Software Foundation, Inc., 
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

As an exception, it is allowed to write an extension of Coco/R that is
used as a plugin in non-free software.

If not otherwise stated, any source code generated by Coco/R (other than 
Coco/R itself) does not fall under the GNU General Public License.
-----------------------------------------------------------------------*/
-->begin
using System;
using System.IO;
using System.Collections;
using System.Text;

-->namespace

public class Token {
	public int kind;    // token kind
	public int pos;     // token position in the source text (starting at 0)
	public int col;     // token column (starting at 0)
	public int line;    // token line (starting at 1)
	public string val;  // token value
	public Token next;  // AW 2003-03-07 Tokens are kept in linked list
}

public class Buffer {
	public const char EOF = (char)256;
	static byte[] buf;
	static int bufLen;
	static int pos;
	// CHANGES by M.KRUEGER
	public static int CountLines(int offset)
	{
		int line = 0;
		for (int i = 0; i <= offset; ++i) {
			if (buf[i] == '\n') {
				++line;
			}
		}
		return line;
	}	
	//EOC
	public static void Fill (Stream s) {
		bufLen = (int) s.Length;
		buf = new byte[bufLen];
		s.Read(buf, 0, bufLen); 
		pos = 0;
	}
	
	public static int Read () {
		if (pos < bufLen) return buf[pos++];
		else return EOF;                          /* pdt */
	}

	public static int Peek () {
		if (pos < bufLen) return buf[pos];
		else return EOF;                          /* pdt */
	}
	
	/* AW 2003-03-10 moved this from ParserGen.cs */
	public static string GetString (int beg, int end) {
		StringBuilder s = new StringBuilder(64);
		int oldPos = Buffer.Pos;
		Buffer.Pos = beg;
		while (beg < end) { s.Append((char)Buffer.Read()); beg++; }
		Buffer.Pos = oldPos;
		return s.ToString();
	}

	public static int Pos {
		get { return pos; }
		set {
			if (value < 0) pos = 0; 
			else if (value >= bufLen) pos = bufLen; 
			else pos = value;
		}
	}
}

public class Scanner {
	const char EOL = '\n';
	const int eofSym = 0; /* pdt */
-->declarations

	static Token t;          // current token
	static char ch;          // current input character
	static int pos;          // column number of current character
	static int line;         // line number of current character
	static int lineStart;    // start position of current line
	static int oldEols;      // EOLs that appeared in a comment;
	static BitArray ignore;  // set of characters to be ignored by the scanner

	static Token tokens;     // the complete input token stream
	static Token pt;         // current peek token
	
	public static void Init (string fileName) {
		FileStream s = null;
		try {
			s = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
			Init(s);
		} catch (IOException) {
			Console.WriteLine("--- Cannot open file {0}", fileName);
			System.Environment.Exit(1);
		} finally {
			if (s != null) s.Close();
		}
	}
	
	public static void Init (Stream s) {
		Buffer.Fill(s);
		pos = -1; line = 1; lineStart = 0;
		oldEols = 0;
		NextCh();
-->initialization
		//--- AW: fill token list
		tokens = new Token();  // first token is a dummy
		Token node = tokens;
		do {
			node.next = NextToken();
			node = node.next;
		} while (node.kind != eofSym);
		node.next = node;
		node.val = "EOF";
		t = pt = tokens;
	}
	
	static void NextCh() {
		if (oldEols > 0) { ch = EOL; oldEols--; } 
		else {
			ch = (char)Buffer.Read(); pos++;
			// replace isolated '\r' by '\n' in order to make
			// eol handling uniform across Windows, Unix and Mac
			if (ch == '\r' && Buffer.Peek() != '\n') ch = EOL;
			if (ch == EOL) { line++; lineStart = pos + 1; }
		}
-->casing
	}

-->comments

	static void CheckLiteral() {
-->literals
	}

	/* AW Scan() renamed to NextToken() */
	static Token NextToken() {
		while (ignore[ch]) NextCh();
-->scan1
		t = new Token();
		t.pos = pos; t.col = pos - lineStart + 1; t.line = line; 
		int state = start[ch];
		StringBuilder buf = new StringBuilder(16);
-->scan2
		
		switch (state) {
			case -1: { t.kind = eofSym; goto done; } // NextCh already done /* pdt */
			case 0: { t.kind = noSym; goto done; }   // NextCh already done
-->scan3
		}
		done: 
		t.val = buf.ToString();
		return t;
	}
	
	/* AW 2003-03-07 get the next token, move on and synch peek token with current */
	public static Token Scan () {
		t = pt = t.next;
		return t;
	}

	/* AW 2003-03-07 get the next token, ignore pragmas */
	public static Token Peek () {
		do {                      // skip pragmas while peeking
			pt = pt.next;
		} while (pt.kind > maxT);
		return pt;
	}
	
	/* AW 2003-03-11 to make sure peek start at current scan position */
	public static void ResetPeek () { pt = t; }

} // end Scanner

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