interpreter/preprocessor/faust-0.9.47mr3/compiler/tlib/symbol.hh

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   3     FAUST compiler
   4         Copyright (C) 2003-2004 GRAME, Centre National de Creation Musicale
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  19  ************************************************************************
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  21
  22 /** \file symbol.hh
  23  * A library to create and manipulate symbols with a unique name.
  24  * A library of functions to create and manipulate symbols with a unique name.
  25  *
  26  *  <b>API:</b>
  27  *
  28  *   - Sym q = symbol("abcd");     <i>returns the symbol of name "abcd"</i>
  29  *   - const char* s = name(q);    <i>returns the name of symbol q</i>
  30  *   - Sym q = unique("TOTO");     <i>returns a new unique symbol of name "TOTOnnn"</i>
  31  *
  32  *  <b>Properties:</b>
  33  *
  34  *     If p and q are two symbols then :
  35  *         p != q  <=>  name(p) != name(q)
  36  *
  37  */
  38
  39
  40 #ifndef     __SYMBOL__
  41 #define     __SYMBOL__
  42
  43 #include <string>
  44 #include <map>
  45
  46 using namespace std;
  47
  48 //--------------------------------SYMBOL-------------------------------------
  49
  50 /**
  51  * Symbols are unique objects with a name stored in a hash table.
  52  */
  53 class Symbol
  54 {
  55
  56  private:
  57
  58         static const int        kHashTableSize = 511;                                   ///< Size of the hash table (a prime number is recommended)
  59     static Symbol*              gSymbolTable[kHashTableSize];                   ///< Hash table used to store the symbols
  60
  61
  62  // Fields
  63     char*                       fName;                                                                          ///< Name of the symbol
  64     unsigned int                        fHash;                                                                          ///< Hash key computed from the name and used to determine the hash table entry
  65     Symbol*                     fNext;                                                                          ///< Next symbol in the hash table entry
  66         void*                   fData;                                                                          ///< Field to user disposal to store additional data
  67
  68  // Constructors & destructors
  69     Symbol (const char* str, unsigned int hsh, Symbol* nxt);    ///< Constructs a new symbol ready to be placed in the hash table
  70    ~Symbol ();                                                                                                  ///< The Destructor is never used
  71
  72  // Others
  73         bool                    equiv (unsigned int hash, const char* str) const ;      ///< Check if the name of the symbol is equal to string \p str
  74         static unsigned int     calcHashKey (const char* str);                          ///< Compute the 32-bits hash key of string \p str
  75
  76  // Static methods
  77         static Symbol*          get (const string& str);                                ///< Get the symbol of name \p str
  78         static Symbol*          get (const char* str);                                  ///< Get the symbol of name \p str
  79         static Symbol*          prefix (const char* str);                               ///< Creates a new symbol of name prefixed by \p str
  80         static bool             isnew (const char* str);                                ///< Returns \b true if no symbol of name \p str exists
  81
  82  public:
  83         ostream&                                print (ostream& fout) const;                                                            ///< print a symbol on a stream
  84
  85         friend Symbol*                  symbol (const char* str);
  86         friend Symbol*                  symbol (const string& str);
  87         friend Symbol*                  unique (const char* str);
  88         friend const char*      name (Symbol* sym);
  89
  90         friend void*                    getUserData (Symbol* sym);
  91         friend void                     setUserData (Symbol* sym, void* d);
  92
  93 };
  94
  95 inline Symbol*                  symbol (const char* str)        { return Symbol::get(str); }    ///< Returns (and creates if new) the symbol of name \p str
  96 inline Symbol*                  symbol (const string& str)      { return Symbol::get(str); }    ///< Returns (and creates if new) the symbol of name \p str
  97 inline Symbol*                  unique (const char* str)        { return Symbol::prefix(str);}  ///< Returns a new unique symbol of name strxxx
  98 inline const char*      name (Symbol* sym)                      { return sym->fName; }                  ///< Returns the name of a symbol
  99
 100 inline void*                    getUserData (Symbol* sym)                       { return sym->fData; }          ///< Returns user data
 101 inline void                     setUserData (Symbol* sym, void* d)      { sym->fData=d; }                       ///< Set user data
 102
 103 inline ostream& operator << (ostream& s, const Symbol& n) { return n.print(s); }
 104
 105
 106 typedef Symbol* Sym;
 107
 108 #endif