lily/include/ly-smobs.icc

   1 /*
   2   ly-smobs.icc -- implement smob glue.
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1999 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7
   8  */
   9
  10 #ifndef LY_SMOBS_ICC
  11 #define LY_SMOBS_ICC
  12
  13 #define IMPLEMENT_SMOBS(CL)\
  14 long CL::smob_tag_;\
  15 static scm_smobfuns CL ## _funs = {                                     \
  16   CL::mark_smob, CL::free_smob,                                         \
  17   CL::print_smob, 0,                                                    \
  18 };                                                                      \
  19 void                                                                    \
  20 CL::init_smobs ()                                                       \
  21 {                                                                       \
  22   smob_tag_ = scm_newsmob (&CL ## _funs);                                       \
  23 }                                                                       \
  24                                                                         \
  25                                                                          \
  26 void                                                                     \
  27 CL::unsmobify_self ()                                                    \
  28 {                                                                        \
  29   SCM s = self_scm_;                                                     \
  30   scm_unprotect_object (s);                                              \
  31                                                                          \
  32   SCM_CAR(self_scm_) = SCM_EOL;  \
  33   SCM_CDR(self_scm_) = SCM_EOL;                                          \
  34   self_scm_ = SCM_EOL;                                                   \
  35 }                                                                        \
  36 \
  37 SCM                                                                     \
  38 CL::smobify_self ()                                                     \
  39 {                                                                       \
  40   if (self_scm_ != SCM_EOL)                                             \
  41     return self_scm_;                                                   \
  42                                                                         \
  43   /*                                                                    \
  44     This is local. We don't assign to self_scm_ directly, to assure     \
  45     that S isn't GC-ed from under us.                                   \
  46    */                                                                   \
  47   SCM s;                                                                \
  48                                                                         \
  49   SCM_NEWCELL(s);                                                       \
  50   self_scm_ = s;                                                        \
  51                                                                         \
  52   SCM_SETCAR(s,smob_tag_);                                              \
  53   void * me_p = this;                                                   \
  54   SCM_SETCDR(s,me_p);                                                   \
  55   scm_protect_object (s);                                               \
  56                                                                         \
  57   do_smobify_self();                                                    \
  58   return s;                                     \
  59 }                                               \
  60 scm_sizet                                       \
  61 CL::free_smob (SCM ses)                         \
  62 {                                               \
  63   CL * s = (CL*) SCM_CDR(ses);                  \
  64   /* someone else did the deed already; this might be an automatic var.*/ \
  65   if (s->self_scm_ != ses)\
  66      return 0; \
  67   SCM_CAR(ses) = SCM_EOL;\
  68                                         \
  69   return sizeof(CL);                            \
  70 }                                               \
  71 ADD_SCM_INIT_FUNC(CL, CL::init_smobs)\
  72
  73
  74 #endif /* LY_SMOBS_ICC */
  75