internal/struct.h

   1 #ifndef INTERNAL_STRUCT_H                                /*-*-C-*-vi:se ft=c:*/
   2 #define INTERNAL_STRUCT_H
   3 /**
   4  * @author     Ruby developers <ruby-core@ruby-lang.org>
   5  * @copyright  This  file  is   a  part  of  the   programming  language  Ruby.
   6  *             Permission  is hereby  granted,  to  either redistribute  and/or
   7  *             modify this file, provided that  the conditions mentioned in the
   8  *             file COPYING are met.  Consult the file for details.
   9  * @brief      Internal header for Struct.
  10  */
  11 #include "ruby/internal/stdbool.h"     /* for bool */
  12 #include "ruby/ruby.h"          /* for struct RBasic */
  13
  14 enum {
  15     RSTRUCT_EMBED_LEN_MASK = RUBY_FL_USER7 | RUBY_FL_USER6 | RUBY_FL_USER5 | RUBY_FL_USER4 |
  16                                  RUBY_FL_USER3 | RUBY_FL_USER2 | RUBY_FL_USER1,
  17     RSTRUCT_EMBED_LEN_SHIFT = (RUBY_FL_USHIFT+1),
  18 };
  19
  20 struct RStruct {
  21     struct RBasic basic;
  22     union {
  23         struct {
  24             long len;
  25             const VALUE *ptr;
  26         } heap;
  27         /* This is a length 1 array because:
  28          *   1. GCC has a bug that does not optimize C flexible array members
  29          *      (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102452)
  30          *   2. Zero length arrays are not supported by all compilers
  31          */
  32         const VALUE ary[1];
  33     } as;
  34 };
  35
  36 #define RSTRUCT(obj) ((struct RStruct *)(obj))
  37
  38 #ifdef RSTRUCT_LEN
  39 # undef RSTRUCT_LEN
  40 #endif
  41
  42 #ifdef RSTRUCT_PTR
  43 # undef RSTRUCT_PTR
  44 #endif
  45
  46 #ifdef RSTRUCT_SET
  47 # undef RSTRUCT_SET
  48 #endif
  49
  50 #ifdef RSTRUCT_GET
  51 # undef RSTRUCT_GET
  52 #endif
  53
  54 #define RSTRUCT_LEN internal_RSTRUCT_LEN
  55 #define RSTRUCT_SET internal_RSTRUCT_SET
  56 #define RSTRUCT_GET internal_RSTRUCT_GET
  57
  58 /* struct.c */
  59 VALUE rb_struct_init_copy(VALUE copy, VALUE s);
  60 VALUE rb_struct_lookup(VALUE s, VALUE idx);
  61 VALUE rb_struct_s_keyword_init(VALUE klass);
  62 static inline long RSTRUCT_EMBED_LEN(VALUE st);
  63 static inline long RSTRUCT_LEN(VALUE st);
  64 static inline int RSTRUCT_LENINT(VALUE st);
  65 static inline const VALUE *RSTRUCT_CONST_PTR(VALUE st);
  66 static inline void RSTRUCT_SET(VALUE st, long k, VALUE v);
  67 static inline VALUE RSTRUCT_GET(VALUE st, long k);
  68
  69 static inline long
  70 RSTRUCT_EMBED_LEN(VALUE st)
  71 {
  72     long ret = FL_TEST_RAW(st, RSTRUCT_EMBED_LEN_MASK);
  73     ret >>= RSTRUCT_EMBED_LEN_SHIFT;
  74     return ret;
  75 }
  76
  77 static inline long
  78 RSTRUCT_LEN(VALUE st)
  79 {
  80     if (FL_TEST_RAW(st, RSTRUCT_EMBED_LEN_MASK)) {
  81         return RSTRUCT_EMBED_LEN(st);
  82     }
  83     else {
  84         return RSTRUCT(st)->as.heap.len;
  85     }
  86 }
  87
  88 static inline int
  89 RSTRUCT_LENINT(VALUE st)
  90 {
  91     return rb_long2int(RSTRUCT_LEN(st));
  92 }
  93
  94 static inline const VALUE *
  95 RSTRUCT_CONST_PTR(VALUE st)
  96 {
  97     const struct RStruct *p = RSTRUCT(st);
  98
  99     if (FL_TEST_RAW(st, RSTRUCT_EMBED_LEN_MASK)) {
 100         return p->as.ary;
 101     }
 102     else {
 103         return p->as.heap.ptr;
 104     }
 105 }
 106
 107 static inline void
 108 RSTRUCT_SET(VALUE st, long k,  VALUE v)
 109 {
 110     RB_OBJ_WRITE(st, &RSTRUCT_CONST_PTR(st)[k], v);
 111 }
 112
 113 static inline VALUE
 114 RSTRUCT_GET(VALUE st, long k)
 115 {
 116     return RSTRUCT_CONST_PTR(st)[k];
 117 }
 118
 119 #endif /* INTERNAL_STRUCT_H */