include/AD/automata/iolexerbuf.h

   1 //////////////////////////////////////////////////////////////////////////////
   2 // NOTICE:
   3 //
   4 // ADLib, Prop and their related set of tools and documentation are in the
   5 // public domain.   The author(s) of this software reserve no copyrights on
   6 // the source code and any code generated using the tools.  You are encouraged
   7 // to use ADLib and Prop to develop software, in both academic and commercial
   8 // settings, and are welcomed to incorporate any part of ADLib and Prop into
   9 // your programs.
  10 //
  11 // Although you are under no obligation to do so, we strongly recommend that
  12 // you give away all software developed using our tools.
  13 //
  14 // We also ask that credit be given to us when ADLib and/or Prop are used in
  15 // your programs, and that this notice be preserved intact in all the source
  16 // code.
  17 //
  18 // This software is still under development and we welcome(read crave for)
  19 // any suggestions and help from the users.
  20 //
  21 // Allen Leung (leunga@cs.nyu.edu)
  22 // 1994-1995
  23 //////////////////////////////////////////////////////////////////////////////
  24
  25 #ifndef iostream_lexer_buffer_h
  26 #define iostream_lexer_buffer_h
  27
  28 #include <AD/automata/lexerbuf.h>  // lexer buffer
  29 #include <iostream>
  30
  31 //////////////////////////////////////////////////////////////////////////////
  32 //  IOstream based lexer buffers.
  33 //////////////////////////////////////////////////////////////////////////////
  34 class IOLexerBuffer : public LexerBuffer {
  35 public:
  36    ///////////////////////////////////////////////////////////////////////////
  37    //  Type definitions
  38    ///////////////////////////////////////////////////////////////////////////
  39    typedef LexerBuffer   Super;
  40    typedef Super::Symbol Symbol;
  41    typedef Super::State  State;
  42    typedef Super::Offset Offset;
  43    typedef Super::Rule   Rule;
  44
  45 protected:
  46    ///////////////////////////////////////////////////////////////////////////
  47    //  Internal buffer and other members
  48    ///////////////////////////////////////////////////////////////////////////
  49    size_t    buffer_size;  // size of the buffer
  50    std::istream * input;        // input stream
  51
  52 public:
  53    ///////////////////////////////////////////////////////////////////////////
  54    //  Constructor and destructor
  55    ///////////////////////////////////////////////////////////////////////////
  56             IOLexerBuffer();
  57             IOLexerBuffer(std::istream&);
  58    virtual ~IOLexerBuffer();
  59
  60    ///////////////////////////////////////////////////////////////////////////
  61    //  Mutators
  62    ///////////////////////////////////////////////////////////////////////////
  63    virtual void set_stream (std::istream&);
  64
  65 protected:
  66    ///////////////////////////////////////////////////////////////////////////
  67    //  Default method for filling the buffer.
  68    //  This should be redefined in derive classes
  69    ///////////////////////////////////////////////////////////////////////////
  70    virtual size_t fill_buffer();
  71    virtual size_t read_buffer(char *, size_t);
  72    void allocate_buffer(size_t);
  73 };
  74
  75 #endif