//========================================================================

//

// Lexer.h

//

// Copyright 1996-2003 Glyph & Cog, LLC

//

//========================================================================

#ifndef LEXER_H

#define LEXER_H

#include <aconf.h>

#include "Object.h"

#include "Stream.h"

class XRef;

#define tokBufSize 128    // size of token buffer

//------------------------------------------------------------------------

// Lexer

//------------------------------------------------------------------------

class Lexer {

public:

  // Construct a lexer for a single stream.  Deletes the stream when

  // lexer is deleted.

  Lexer(XRef *xref, Stream *str);

  // Construct a lexer for a stream or array of streams (assumes obj

  // is either a stream or array of streams).

  Lexer(XRef *xref, Object *obj);

  // Destructor.

  ~Lexer();

  // Get the next object from the input stream.

  Object *getObj(Object *obj);

  // Skip to the beginning of the next line in the input stream.

  void skipToNextLine();

  // Skip to the end of the input stream.

  void skipToEOF();

  // Skip over one character.

  void skipChar() { getChar(); }

  // Get stream index (for arrays of streams).

  int getStreamIndex() { return strPtr; }

  // Get stream.

  Stream *getStream()

    { return curStr.isNone() ? (Stream *)NULL : curStr.getStream(); }

  // Get current position in file.

  GFileOffset getPos()

    { return curStr.isNone() ? -1 : curStr.streamGetPos(); }

  // Set position in file.

  void setPos(GFileOffset pos, int dir = 0)

    { if (!curStr.isNone()) curStr.streamSetPos(pos, dir); }

  // Returns true if <c> is a whitespace character.

  static GBool isSpace(int c);

private:

  int getChar();

  int lookChar();

  Array *streams;   // array of input streams

  int strPtr;     // index of current stream

  Object curStr;    // current stream

  GBool freeArray;    // should lexer free the streams array?

  char tokBuf[tokBufSize];  // temporary token buffer

};

#endif