lily/include/scm-hash.hh

   1 /*
   2   scm-hash.hh -- declare Scheme hasher.
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1999--2001 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7
   8  */
   9
  10 #ifndef SCM_HASH_HH
  11 #define SCM_HASH_HH
  12
  13
  14 #include <map>
  15
  16 #include "lily-guile.hh"
  17 #include "smobs.hh"
  18
  19
  20 struct SCM_less
  21 {
  22   bool operator () (SCM s1, SCM s2) const
  23   {
  24     return long (s1) < long (s2);
  25   }
  26 };
  27
  28 typedef map<SCM,SCM, SCM_less> Scm_stl_map;
  29
  30 /**
  31    auto resizing hash table.
  32
  33    1. ALWAYS USE THIS AS VIA A POINTER, i.e.
  34
  35    class Foo {
  36     Scheme_hash_table * tab;
  37    };
  38
  39    and NOT
  40
  41    class Foo {
  42     Scheme_hash_table tab;
  43    }
  44
  45
  46    2. UPON DESTRUCTION, DO
  47
  48    scm_unprotect_object (tab->self_scm_);
  49
  50
  51
  52
  53    TODO:
  54
  55   - This should come from GUILE. We're typically doing double work,
  56    because KEY already is a symbol, and is looked up in a symbol
  57    hashtable.
  58
  59   - use GUILE hashtables iso STL.
  60  */
  61 class Scheme_hash_table :  private Scm_stl_map
  62 {
  63 public:
  64   bool try_retrieve (SCM key, SCM *val);
  65   bool elem_b (SCM key) const;
  66
  67   /**
  68      WARNING: putting something in assumes responsibility for cleaning
  69      up.  */
  70   void set (SCM k, SCM v);
  71   SCM get (SCM k) const;
  72   void remove (SCM k);
  73   Scheme_hash_table ();
  74   void operator = (Scheme_hash_table const &);
  75   Scheme_hash_table (Scheme_hash_table const &);
  76
  77   SCM to_alist () const;
  78   DECLARE_SMOBS (Scheme_hash_table,foo);
  79 };
  80
  81 #endif /* SCM_HASH_HH */
  82