mrbgems/mruby-struct/src/struct.c

   1 /*
   2 ** struct.c - Struct class
   3 **
   4 ** See Copyright Notice in mruby.h
   5 */
   6
   7 #include <string.h>
   8 #include <stdarg.h>
   9 #include "mruby.h"
  10 #include "mruby/array.h"
  11 #include "mruby/string.h"
  12 #include "mruby/class.h"
  13 #include "mruby/variable.h"
  14 #include "mruby/hash.h"
  15 #include "mruby/range.h"
  16
  17 #define RSTRUCT_LEN(st) RARRAY_LEN(st)
  18 #define RSTRUCT_PTR(st) RARRAY_PTR(st)
  19
  20 static struct RClass *
  21 struct_class(mrb_state *mrb)
  22 {
  23   return mrb_class_get(mrb, "Struct");
  24 }
  25
  26 static inline mrb_value
  27 struct_ivar_get(mrb_state *mrb, mrb_value c, mrb_sym id)
  28 {
  29   struct RClass* kclass;
  30   struct RClass* sclass = struct_class(mrb);
  31   mrb_value ans;
  32
  33   for (;;) {
  34     ans = mrb_iv_get(mrb, c, id);
  35     if (!mrb_nil_p(ans)) return ans;
  36     kclass = RCLASS_SUPER(c);
  37     if (kclass == 0 || kclass == sclass)
  38       return mrb_nil_value();
  39     c = mrb_obj_value(kclass);
  40   }
  41 }
  42
  43 static mrb_value
  44 mrb_struct_iv_get(mrb_state *mrb, mrb_value c, const char *name)
  45 {
  46   return struct_ivar_get(mrb, c, mrb_intern_cstr(mrb, name));
  47 }
  48
  49 static mrb_value
  50 mrb_struct_s_members(mrb_state *mrb, mrb_value klass)
  51 {
  52   mrb_value members = struct_ivar_get(mrb, klass, mrb_intern_lit(mrb, "__members__"));
  53
  54   if (mrb_nil_p(members)) {
  55     mrb_raise(mrb, E_TYPE_ERROR, "uninitialized struct");
  56   }
  57   if (!mrb_array_p(members)) {
  58     mrb_raise(mrb, E_TYPE_ERROR, "corrupted struct");
  59   }
  60   return members;
  61 }
  62
  63 static mrb_value
  64 mrb_struct_members(mrb_state *mrb, mrb_value s)
  65 {
  66   mrb_value members = mrb_struct_s_members(mrb, mrb_obj_value(mrb_obj_class(mrb, s)));
  67   if (!strcmp(mrb_class_name(mrb, mrb_obj_class(mrb, s)), "Struct")) {
  68     if (RSTRUCT_LEN(s) != RARRAY_LEN(members)) {
  69       mrb_raisef(mrb, E_TYPE_ERROR,
  70                  "struct size differs (%S required %S given)",
  71                  mrb_fixnum_value(RARRAY_LEN(members)), mrb_fixnum_value(RSTRUCT_LEN(s)));
  72     }
  73   }
  74   return members;
  75 }
  76
  77 static mrb_value
  78 mrb_struct_s_members_m(mrb_state *mrb, mrb_value klass)
  79 {
  80   mrb_value members, ary;
  81   mrb_value *p, *pend;
  82
  83   members = mrb_struct_s_members(mrb, klass);
  84   ary = mrb_ary_new_capa(mrb, RARRAY_LEN(members));
  85   p = RARRAY_PTR(members); pend = p + RARRAY_LEN(members);
  86   while (p < pend) {
  87     mrb_ary_push(mrb, ary, *p);
  88     p++;
  89   }
  90   return ary;
  91 }
  92
  93 /* 15.2.18.4.6  */
  94 /*
  95  *  call-seq:
  96  *     struct.members    -> array
  97  *
  98  *  Returns an array of strings representing the names of the instance
  99  *  variables.
 100  *
 101  *     Customer = Struct.new(:name, :address, :zip)
 102  *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
 103  *     joe.members   #=> [:name, :address, :zip]
 104  */
 105
 106 static mrb_value
 107 mrb_struct_members_m(mrb_state *mrb, mrb_value obj)
 108 {
 109   return mrb_struct_s_members_m(mrb, mrb_obj_value(mrb_obj_class(mrb, obj)));
 110 }
 111
 112 static mrb_value
 113 mrb_struct_getmember(mrb_state *mrb, mrb_value obj, mrb_sym id)
 114 {
 115   mrb_value members, slot, *ptr, *ptr_members;
 116   mrb_int i, len;
 117
 118   ptr = RSTRUCT_PTR(obj);
 119   members = mrb_struct_members(mrb, obj);
 120   ptr_members = RARRAY_PTR(members);
 121   slot = mrb_symbol_value(id);
 122   len = RARRAY_LEN(members);
 123   for (i=0; i<len; i++) {
 124     if (mrb_obj_equal(mrb, ptr_members[i], slot)) {
 125       return ptr[i];
 126     }
 127   }
 128   mrb_raisef(mrb, E_INDEX_ERROR, "`%S' is not a struct member", mrb_sym2str(mrb, id));
 129   return mrb_nil_value();       /* not reached */
 130 }
 131
 132 static mrb_value
 133 mrb_struct_ref(mrb_state *mrb, mrb_value obj)
 134 {
 135   return mrb_struct_getmember(mrb, obj, mrb->c->ci->mid);
 136 }
 137
 138 static mrb_value mrb_struct_ref0(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[0];}
 139 static mrb_value mrb_struct_ref1(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[1];}
 140 static mrb_value mrb_struct_ref2(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[2];}
 141 static mrb_value mrb_struct_ref3(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[3];}
 142 static mrb_value mrb_struct_ref4(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[4];}
 143 static mrb_value mrb_struct_ref5(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[5];}
 144 static mrb_value mrb_struct_ref6(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[6];}
 145 static mrb_value mrb_struct_ref7(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[7];}
 146 static mrb_value mrb_struct_ref8(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[8];}
 147 static mrb_value mrb_struct_ref9(mrb_state* mrb, mrb_value obj) {return RSTRUCT_PTR(obj)[9];}
 148
 149 #define numberof(array) (int)(sizeof(array) / sizeof((array)[0]))
 150 #define N_REF_FUNC numberof(ref_func)
 151
 152 static mrb_value (*const ref_func[])(mrb_state*, mrb_value) = {
 153   mrb_struct_ref0,
 154   mrb_struct_ref1,
 155   mrb_struct_ref2,
 156   mrb_struct_ref3,
 157   mrb_struct_ref4,
 158   mrb_struct_ref5,
 159   mrb_struct_ref6,
 160   mrb_struct_ref7,
 161   mrb_struct_ref8,
 162   mrb_struct_ref9,
 163 };
 164
 165 static mrb_sym
 166 mrb_id_attrset(mrb_state *mrb, mrb_sym id)
 167 {
 168   const char *name;
 169   char *buf;
 170   mrb_int len;
 171   mrb_sym mid;
 172
 173   name = mrb_sym2name_len(mrb, id, &len);
 174   buf = (char *)mrb_malloc(mrb, (size_t)len+2);
 175   memcpy(buf, name, (size_t)len);
 176   buf[len] = '=';
 177   buf[len+1] = '\0';
 178
 179   mid = mrb_intern(mrb, buf, len+1);
 180   mrb_free(mrb, buf);
 181   return mid;
 182 }
 183
 184 static mrb_value
 185 mrb_struct_set(mrb_state *mrb, mrb_value obj, mrb_value val)
 186 {
 187   const char *name;
 188   size_t i, len;
 189   mrb_int slen;
 190   mrb_sym mid;
 191   mrb_value members, slot, *ptr, *ptr_members;
 192
 193   /* get base id */
 194   name = mrb_sym2name_len(mrb, mrb->c->ci->mid, &slen);
 195   mid = mrb_intern(mrb, name, slen-1); /* omit last "=" */
 196
 197   members = mrb_struct_members(mrb, obj);
 198   ptr_members = RARRAY_PTR(members);
 199   len = RARRAY_LEN(members);
 200   ptr = RSTRUCT_PTR(obj);
 201   for (i=0; i<len; i++) {
 202     slot = ptr_members[i];
 203     if (mrb_symbol(slot) == mid) {
 204       return ptr[i] = val;
 205     }
 206   }
 207   mrb_raisef(mrb, E_INDEX_ERROR, "`%S' is not a struct member", mrb_sym2str(mrb, mid));
 208   return mrb_nil_value();       /* not reached */
 209 }
 210
 211 static mrb_value
 212 mrb_struct_set_m(mrb_state *mrb, mrb_value obj)
 213 {
 214   mrb_value val;
 215
 216   mrb_get_args(mrb, "o", &val);
 217   return mrb_struct_set(mrb, obj, val);
 218 }
 219
 220 #define is_notop_id(id) (id) /* ((id)>tLAST_TOKEN) */
 221 #define is_local_id(id) (is_notop_id(id)) /* &&((id)&ID_SCOPE_MASK)==ID_LOCAL) */
 222 static int
 223 mrb_is_local_id(mrb_sym id)
 224 {
 225   return is_local_id(id);
 226 }
 227
 228 #define is_const_id(id) (is_notop_id(id)) /* &&((id)&ID_SCOPE_MASK)==ID_CONST) */
 229 static int
 230 mrb_is_const_id(mrb_sym id)
 231 {
 232   return is_const_id(id);
 233 }
 234
 235 static mrb_value
 236 make_struct(mrb_state *mrb, mrb_value name, mrb_value members, struct RClass * klass)
 237 {
 238   mrb_value nstr, *ptr_members;
 239   mrb_sym id;
 240   mrb_int i, len;
 241   struct RClass *c;
 242   int ai;
 243
 244   if (mrb_nil_p(name)) {
 245     c = mrb_class_new(mrb, klass);
 246   }
 247   else {
 248     /* old style: should we warn? */
 249     name = mrb_str_to_str(mrb, name);
 250     id = mrb_obj_to_sym(mrb, name);
 251     if (!mrb_is_const_id(id)) {
 252       mrb_name_error(mrb, id, "identifier %S needs to be constant", name);
 253     }
 254     if (mrb_const_defined_at(mrb, klass, id)) {
 255       mrb_warn(mrb, "redefining constant Struct::%S", name);
 256       /* ?rb_mod_remove_const(klass, mrb_sym2name(mrb, id)); */
 257     }
 258     c = mrb_define_class_under(mrb, klass, RSTRING_PTR(name), klass);
 259   }
 260   MRB_SET_INSTANCE_TT(c, MRB_TT_ARRAY);
 261   nstr = mrb_obj_value(c);
 262   mrb_iv_set(mrb, nstr, mrb_intern_lit(mrb, "__members__"), members);
 263
 264   mrb_define_class_method(mrb, c, "new", mrb_instance_new, MRB_ARGS_ANY());
 265   mrb_define_class_method(mrb, c, "[]", mrb_instance_new, MRB_ARGS_ANY());
 266   mrb_define_class_method(mrb, c, "members", mrb_struct_s_members_m, MRB_ARGS_NONE());
 267   /* RSTRUCT(nstr)->basic.c->super = c->c; */
 268   ptr_members = RARRAY_PTR(members);
 269   len = RARRAY_LEN(members);
 270   ai = mrb_gc_arena_save(mrb);
 271   for (i=0; i< len; i++) {
 272     mrb_sym id = mrb_symbol(ptr_members[i]);
 273     if (mrb_is_local_id(id) || mrb_is_const_id(id)) {
 274       if (i < N_REF_FUNC) {
 275         mrb_define_method_id(mrb, c, id, ref_func[i], MRB_ARGS_NONE());
 276       }
 277       else {
 278         mrb_define_method_id(mrb, c, id, mrb_struct_ref, MRB_ARGS_NONE());
 279       }
 280       mrb_define_method_id(mrb, c, mrb_id_attrset(mrb, id), mrb_struct_set_m, MRB_ARGS_REQ(1));
 281       mrb_gc_arena_restore(mrb, ai);
 282     }
 283   }
 284   return nstr;
 285 }
 286
 287 static mrb_value
 288 mrb_struct_define(mrb_state *mrb, const char *name, ...)
 289 {
 290   va_list ar;
 291   mrb_value nm, ary;
 292   char *mem;
 293
 294   if (!name) nm = mrb_nil_value();
 295   else nm = mrb_str_new_cstr(mrb, name);
 296   ary = mrb_ary_new(mrb);
 297
 298   va_start(ar, name);
 299   while ((mem = va_arg(ar, char*)) != 0) {
 300     mrb_sym slot = mrb_intern_cstr(mrb, mem);
 301     mrb_ary_push(mrb, ary, mrb_symbol_value(slot));
 302   }
 303   va_end(ar);
 304
 305   return make_struct(mrb, nm, ary, struct_class(mrb));
 306 }
 307
 308 /* 15.2.18.3.1  */
 309 /*
 310  *  call-seq:
 311  *     Struct.new( [aString] [, aSym]+> )    -> StructClass
 312  *     StructClass.new(arg, ...)             -> obj
 313  *     StructClass[arg, ...]                 -> obj
 314  *
 315  *  Creates a new class, named by <i>aString</i>, containing accessor
 316  *  methods for the given symbols. If the name <i>aString</i> is
 317  *  omitted, an anonymous structure class will be created. Otherwise,
 318  *  the name of this struct will appear as a constant in class
 319  *  <code>Struct</code>, so it must be unique for all
 320  *  <code>Struct</code>s in the system and should start with a capital
 321  *  letter. Assigning a structure class to a constant effectively gives
 322  *  the class the name of the constant.
 323  *
 324  *  <code>Struct::new</code> returns a new <code>Class</code> object,
 325  *  which can then be used to create specific instances of the new
 326  *  structure. The number of actual parameters must be
 327  *  less than or equal to the number of attributes defined for this
 328  *  class; unset parameters default to <code>nil</code>.  Passing too many
 329  *  parameters will raise an <code>ArgumentError</code>.
 330  *
 331  *  The remaining methods listed in this section (class and instance)
 332  *  are defined for this generated class.
 333  *
 334  *     # Create a structure with a name in Struct
 335  *     Struct.new("Customer", :name, :address)    #=> Struct::Customer
 336  *     Struct::Customer.new("Dave", "123 Main")   #=> #<struct Struct::Customer name="Dave", address="123 Main">
 337  *
 338  *     # Create a structure named by its constant
 339  *     Customer = Struct.new(:name, :address)     #=> Customer
 340  *     Customer.new("Dave", "123 Main")           #=> #<struct Customer name="Dave", address="123 Main">
 341  */
 342 static mrb_value
 343 mrb_struct_s_def(mrb_state *mrb, mrb_value klass)
 344 {
 345   mrb_value name, rest;
 346   mrb_value *pargv;
 347   int argcnt;
 348   mrb_int i;
 349   mrb_value b, st;
 350   mrb_sym id;
 351   mrb_value *argv;
 352   mrb_int argc;
 353
 354   name = mrb_nil_value();
 355   rest = mrb_nil_value();
 356   mrb_get_args(mrb, "*&", &argv, &argc, &b);
 357   if (argc == 0) { /* special case to avoid crash */
 358     rest = mrb_ary_new(mrb);
 359   }
 360   else {
 361     if (argc > 0) name = argv[0];
 362     if (argc > 1) rest = argv[1];
 363     if (mrb_array_p(rest)) {
 364       if (!mrb_nil_p(name) && mrb_symbol_p(name)) {
 365         /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
 366         mrb_ary_unshift(mrb, rest, name);
 367         name = mrb_nil_value();
 368       }
 369     }
 370     else {
 371       pargv = &argv[1];
 372       argcnt = argc-1;
 373       if (!mrb_nil_p(name) && mrb_symbol_p(name)) {
 374         /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
 375         name = mrb_nil_value();
 376         pargv = &argv[0];
 377         argcnt++;
 378       }
 379       rest = mrb_ary_new_from_values(mrb, argcnt, pargv);
 380     }
 381     for (i=0; i<RARRAY_LEN(rest); i++) {
 382       id = mrb_obj_to_sym(mrb, RARRAY_PTR(rest)[i]);
 383       RARRAY_PTR(rest)[i] = mrb_symbol_value(id);
 384     }
 385   }
 386   st = make_struct(mrb, name, rest, struct_class(mrb));
 387   if (!mrb_nil_p(b)) {
 388     mrb_yield_with_class(mrb, b, 1, &st, st, mrb_class_ptr(klass));
 389   }
 390
 391   return st;
 392 }
 393
 394 static int
 395 num_members(mrb_state *mrb, struct RClass *klass)
 396 {
 397   mrb_value members;
 398
 399   members = struct_ivar_get(mrb, mrb_obj_value(klass), mrb_intern_lit(mrb, "__members__"));
 400   if (!mrb_array_p(members)) {
 401     mrb_raise(mrb, E_TYPE_ERROR, "broken members");
 402   }
 403   return RARRAY_LEN(members);
 404 }
 405
 406 /* 15.2.18.4.8  */
 407 /*
 408  */
 409 static mrb_value
 410 mrb_struct_initialize_withArg(mrb_state *mrb, int argc, mrb_value *argv, mrb_value self)
 411 {
 412   struct RClass *klass = mrb_obj_class(mrb, self);
 413   int i, n;
 414
 415   n = num_members(mrb, klass);
 416   if (n < argc) {
 417     mrb_raise(mrb, E_ARGUMENT_ERROR, "struct size differs");
 418   }
 419
 420   for (i = 0; i < argc; i++) {
 421     mrb_ary_set(mrb, self, i, argv[i]);
 422   }
 423   for (i = argc; i < n; i++) {
 424     mrb_ary_set(mrb, self, i, mrb_nil_value());
 425   }
 426   return self;
 427 }
 428
 429 static mrb_value
 430 mrb_struct_initialize_m(mrb_state *mrb, /*int argc, mrb_value *argv,*/ mrb_value self)
 431 {
 432   mrb_value *argv;
 433   mrb_int argc;
 434
 435   mrb_get_args(mrb, "*", &argv, &argc);
 436   return mrb_struct_initialize_withArg(mrb, argc, argv, self);
 437 }
 438
 439 static mrb_value
 440 mrb_struct_initialize(mrb_state *mrb, mrb_value self, mrb_value values)
 441 {
 442   return mrb_struct_initialize_withArg(mrb, RARRAY_LEN(values), RARRAY_PTR(values), self);
 443 }
 444
 445 static mrb_value
 446 inspect_struct(mrb_state *mrb, mrb_value s, int recur)
 447 {
 448   const char *cn = mrb_class_name(mrb, mrb_obj_class(mrb, s));
 449   mrb_value members, str = mrb_str_new_lit(mrb, "#<struct ");
 450   mrb_value *ptr, *ptr_members;
 451   mrb_int i, len;
 452
 453   if (cn) {
 454     mrb_str_append(mrb, str, mrb_str_new_cstr(mrb, cn));
 455   }
 456   if (recur) {
 457     return mrb_str_cat_lit(mrb, str, ":...>");
 458   }
 459
 460   members = mrb_struct_members(mrb, s);
 461   ptr_members = RARRAY_PTR(members);
 462   ptr = RSTRUCT_PTR(s);
 463   len = RSTRUCT_LEN(s);
 464   for (i=0; i<len; i++) {
 465     mrb_value slot;
 466     mrb_sym id;
 467
 468     if (i > 0) {
 469       mrb_str_cat_lit(mrb, str, ", ");
 470     }
 471     else if (cn) {
 472       mrb_str_cat_lit(mrb, str, " ");
 473     }
 474     slot = ptr_members[i];
 475     id = mrb_symbol(slot);
 476     if (mrb_is_local_id(id) || mrb_is_const_id(id)) {
 477       const char *name;
 478       mrb_int len;
 479
 480       name = mrb_sym2name_len(mrb, id, &len);
 481       mrb_str_append(mrb, str, mrb_str_new(mrb, name, len));
 482     }
 483     else {
 484       mrb_str_append(mrb, str, mrb_inspect(mrb, slot));
 485     }
 486     mrb_str_cat_lit(mrb, str, "=");
 487     mrb_str_append(mrb, str, mrb_inspect(mrb, ptr[i]));
 488   }
 489   mrb_str_cat_lit(mrb, str, ">");
 490
 491   return str;
 492 }
 493
 494 /*
 495  * call-seq:
 496  *   struct.to_s      -> string
 497  *   struct.inspect   -> string
 498  *
 499  * Describe the contents of this struct in a string.
 500  */
 501 static mrb_value
 502 mrb_struct_inspect(mrb_state *mrb, mrb_value s)
 503 {
 504   return inspect_struct(mrb, s, 0);
 505 }
 506
 507 /* 15.2.18.4.9  */
 508 /* :nodoc: */
 509 static mrb_value
 510 mrb_struct_init_copy(mrb_state *mrb, mrb_value copy)
 511 {
 512   mrb_value s;
 513   mrb_int i, len;
 514
 515   mrb_get_args(mrb, "o", &s);
 516
 517   if (mrb_obj_equal(mrb, copy, s)) return copy;
 518   if (!mrb_obj_is_instance_of(mrb, s, mrb_obj_class(mrb, copy))) {
 519     mrb_raise(mrb, E_TYPE_ERROR, "wrong argument class");
 520   }
 521   if (!mrb_array_p(s)) {
 522     mrb_raise(mrb, E_TYPE_ERROR, "corrupted struct");
 523   }
 524   if (RSTRUCT_LEN(copy) != RSTRUCT_LEN(s)) {
 525     mrb_raise(mrb, E_TYPE_ERROR, "struct size mismatch");
 526   }
 527   len = RSTRUCT_LEN(copy);
 528   for (i = 0; i < len; i++) {
 529     mrb_ary_set(mrb, copy, i, RSTRUCT_PTR(s)[i]);
 530   }
 531   return copy;
 532 }
 533
 534 static mrb_value
 535 struct_aref_sym(mrb_state *mrb, mrb_value s, mrb_sym id)
 536 {
 537   mrb_value *ptr, members, *ptr_members;
 538   mrb_int i, len;
 539
 540   ptr = RSTRUCT_PTR(s);
 541   members = mrb_struct_members(mrb, s);
 542   ptr_members = RARRAY_PTR(members);
 543   len = RARRAY_LEN(members);
 544   for (i=0; i<len; i++) {
 545     if (mrb_symbol(ptr_members[i]) == id) {
 546       return ptr[i];
 547     }
 548   }
 549   mrb_raisef(mrb, E_INDEX_ERROR, "no member '%S' in struct", mrb_sym2str(mrb, id));
 550   return mrb_nil_value();       /* not reached */
 551 }
 552
 553 static mrb_value
 554 struct_aref_int(mrb_state *mrb, mrb_value s, mrb_int i)
 555 {
 556   if (i < 0) i = RSTRUCT_LEN(s) + i;
 557   if (i < 0)
 558       mrb_raisef(mrb, E_INDEX_ERROR,
 559                  "offset %S too small for struct(size:%S)",
 560                  mrb_fixnum_value(i), mrb_fixnum_value(RSTRUCT_LEN(s)));
 561   if (RSTRUCT_LEN(s) <= i)
 562     mrb_raisef(mrb, E_INDEX_ERROR,
 563                "offset %S too large for struct(size:%S)",
 564                mrb_fixnum_value(i), mrb_fixnum_value(RSTRUCT_LEN(s)));
 565   return RSTRUCT_PTR(s)[i];
 566 }
 567
 568 /* 15.2.18.4.2  */
 569 /*
 570  *  call-seq:
 571  *     struct[symbol]    -> anObject
 572  *     struct[fixnum]    -> anObject
 573  *
 574  *  Attribute Reference---Returns the value of the instance variable
 575  *  named by <i>symbol</i>, or indexed (0..length-1) by
 576  *  <i>fixnum</i>. Will raise <code>NameError</code> if the named
 577  *  variable does not exist, or <code>IndexError</code> if the index is
 578  *  out of range.
 579  *
 580  *     Customer = Struct.new(:name, :address, :zip)
 581  *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
 582  *
 583  *     joe["name"]   #=> "Joe Smith"
 584  *     joe[:name]    #=> "Joe Smith"
 585  *     joe[0]        #=> "Joe Smith"
 586  */
 587 static mrb_value
 588 mrb_struct_aref(mrb_state *mrb, mrb_value s)
 589 {
 590   mrb_value idx;
 591
 592   mrb_get_args(mrb, "o", &idx);
 593   if (mrb_string_p(idx)) {
 594     mrb_value sym = mrb_check_intern_str(mrb, idx);
 595
 596     if (mrb_nil_p(sym)) {
 597       mrb_raisef(mrb, E_INDEX_ERROR, "no member '%S' in struct", idx);
 598     }
 599     idx = sym;
 600   }
 601   if (mrb_symbol_p(idx)) {
 602     return struct_aref_sym(mrb, s, mrb_symbol(idx));
 603   }
 604   return struct_aref_int(mrb, s, mrb_int(mrb, idx));
 605 }
 606
 607 static mrb_value
 608 mrb_struct_aset_sym(mrb_state *mrb, mrb_value s, mrb_sym id, mrb_value val)
 609 {
 610   mrb_value members, *ptr, *ptr_members;
 611   mrb_int i, len;
 612
 613   members = mrb_struct_members(mrb, s);
 614   len = RARRAY_LEN(members);
 615   if (RSTRUCT_LEN(s) != len) {
 616     mrb_raisef(mrb, E_TYPE_ERROR,
 617                "struct size differs (%S required %S given)",
 618                mrb_fixnum_value(len), mrb_fixnum_value(RSTRUCT_LEN(s)));
 619   }
 620   ptr = RSTRUCT_PTR(s);
 621   ptr_members = RARRAY_PTR(members);
 622   for (i=0; i<len; i++) {
 623     if (mrb_symbol(ptr_members[i]) == id) {
 624       ptr[i] = val;
 625       return val;
 626     }
 627   }
 628   mrb_raisef(mrb, E_INDEX_ERROR, "no member '%S' in struct", mrb_sym2str(mrb, id));
 629   return val;                   /* not reach */
 630 }
 631
 632 /* 15.2.18.4.3  */
 633 /*
 634  *  call-seq:
 635  *     struct[symbol] = obj    -> obj
 636  *     struct[fixnum] = obj    -> obj
 637  *
 638  *  Attribute Assignment---Assigns to the instance variable named by
 639  *  <i>symbol</i> or <i>fixnum</i> the value <i>obj</i> and
 640  *  returns it. Will raise a <code>NameError</code> if the named
 641  *  variable does not exist, or an <code>IndexError</code> if the index
 642  *  is out of range.
 643  *
 644  *     Customer = Struct.new(:name, :address, :zip)
 645  *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
 646  *
 647  *     joe["name"] = "Luke"
 648  *     joe[:zip]   = "90210"
 649  *
 650  *     joe.name   #=> "Luke"
 651  *     joe.zip    #=> "90210"
 652  */
 653
 654 static mrb_value
 655 mrb_struct_aset(mrb_state *mrb, mrb_value s)
 656 {
 657   mrb_int i;
 658   mrb_value idx;
 659   mrb_value val;
 660
 661   mrb_get_args(mrb, "oo", &idx, &val);
 662
 663   if (mrb_string_p(idx)) {
 664     mrb_value sym = mrb_check_intern_str(mrb, idx);
 665
 666     if (mrb_nil_p(sym)) {
 667       mrb_raisef(mrb, E_INDEX_ERROR, "no member '%S' in struct", idx);
 668     }
 669     idx = sym;
 670   }
 671   if (mrb_symbol_p(idx)) {
 672     return mrb_struct_aset_sym(mrb, s, mrb_symbol(idx), val);
 673   }
 674
 675   i = mrb_int(mrb, idx);
 676   if (i < 0) i = RSTRUCT_LEN(s) + i;
 677   if (i < 0) {
 678     mrb_raisef(mrb, E_INDEX_ERROR,
 679                "offset %S too small for struct(size:%S)",
 680                mrb_fixnum_value(i), mrb_fixnum_value(RSTRUCT_LEN(s)));
 681   }
 682   if (RSTRUCT_LEN(s) <= i) {
 683     mrb_raisef(mrb, E_INDEX_ERROR,
 684                "offset %S too large for struct(size:%S)",
 685                mrb_fixnum_value(i), mrb_fixnum_value(RSTRUCT_LEN(s)));
 686   }
 687   return RSTRUCT_PTR(s)[i] = val;
 688 }
 689
 690 /* 15.2.18.4.1  */
 691 /*
 692  *  call-seq:
 693  *     struct == other_struct     -> true or false
 694  *
 695  *  Equality---Returns <code>true</code> if <i>other_struct</i> is
 696  *  equal to this one: they must be of the same class as generated by
 697  *  <code>Struct::new</code>, and the values of all instance variables
 698  *  must be equal (according to <code>Object#==</code>).
 699  *
 700  *     Customer = Struct.new(:name, :address, :zip)
 701  *     joe   = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
 702  *     joejr = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
 703  *     jane  = Customer.new("Jane Doe", "456 Elm, Anytown NC", 12345)
 704  *     joe == joejr   #=> true
 705  *     joe == jane    #=> false
 706  */
 707
 708 static mrb_value
 709 mrb_struct_equal(mrb_state *mrb, mrb_value s)
 710 {
 711   mrb_value s2;
 712   mrb_value *ptr, *ptr2;
 713   mrb_int i, len;
 714   mrb_bool equal_p;
 715
 716   mrb_get_args(mrb, "o", &s2);
 717   if (mrb_obj_equal(mrb, s, s2)) {
 718     equal_p = 1;
 719   }
 720   else if (!strcmp(mrb_class_name(mrb, mrb_obj_class(mrb, s)), "Struct") ||
 721            mrb_obj_class(mrb, s) != mrb_obj_class(mrb, s2)) {
 722     equal_p = 0;
 723   }
 724   else if (RSTRUCT_LEN(s) != RSTRUCT_LEN(s2)) {
 725     mrb_bug(mrb, "inconsistent struct"); /* should never happen */
 726     equal_p = 0; /* This substuture is just to suppress warnings. never called. */
 727   }
 728   else {
 729     ptr = RSTRUCT_PTR(s);
 730     ptr2 = RSTRUCT_PTR(s2);
 731     len = RSTRUCT_LEN(s);
 732     equal_p = 1;
 733     for (i=0; i<len; i++) {
 734       if (!mrb_equal(mrb, ptr[i], ptr2[i])) {
 735         equal_p = 0;
 736         break;
 737       }
 738     }
 739   }
 740
 741   return mrb_bool_value(equal_p);
 742 }
 743
 744 /* 15.2.18.4.12(x)  */
 745 /*
 746  * code-seq:
 747  *   struct.eql?(other)   -> true or false
 748  *
 749  * Two structures are equal if they are the same object, or if all their
 750  * fields are equal (using <code>eql?</code>).
 751  */
 752 static mrb_value
 753 mrb_struct_eql(mrb_state *mrb, mrb_value s)
 754 {
 755   mrb_value s2;
 756   mrb_value *ptr, *ptr2;
 757   mrb_int i, len;
 758   mrb_bool eql_p;
 759
 760   mrb_get_args(mrb, "o", &s2);
 761   if (mrb_obj_equal(mrb, s, s2)) {
 762     eql_p = 1;
 763   }
 764   else if (strcmp(mrb_class_name(mrb, mrb_obj_class(mrb, s2)), "Struct") ||
 765            mrb_obj_class(mrb, s) != mrb_obj_class(mrb, s2)) {
 766     eql_p = 0;
 767   }
 768   else if (RSTRUCT_LEN(s) != RSTRUCT_LEN(s2)) {
 769     mrb_bug(mrb, "inconsistent struct"); /* should never happen */
 770     eql_p = 0; /* This substuture is just to suppress warnings. never called. */
 771   }
 772   else {
 773     ptr = RSTRUCT_PTR(s);
 774     ptr2 = RSTRUCT_PTR(s2);
 775     len = RSTRUCT_LEN(s);
 776     eql_p = 1;
 777     for (i=0; i<len; i++) {
 778       if (!mrb_eql(mrb, ptr[i], ptr2[i])) {
 779         eql_p = 0;
 780         break;
 781       }
 782     }
 783   }
 784
 785   return mrb_bool_value(eql_p);
 786 }
 787
 788 /*
 789  * call-seq:
 790  *    struct.length   -> Fixnum
 791  *    struct.size     -> Fixnum
 792  *
 793  * Returns number of struct members.
 794  */
 795 static mrb_value
 796 mrb_struct_len(mrb_state *mrb, mrb_value self)
 797 {
 798   return mrb_fixnum_value(RSTRUCT_LEN(self));
 799 }
 800
 801 /*
 802  * call-seq:
 803  *    struct.to_a    -> array
 804  *    struct.values  -> array
 805  *
 806  * Create an array from struct values.
 807  */
 808 static mrb_value
 809 mrb_struct_to_a(mrb_state *mrb, mrb_value self)
 810 {
 811   return mrb_ary_new_from_values(mrb, RSTRUCT_LEN(self), RSTRUCT_PTR(self));
 812 }
 813
 814 /*
 815  * call-seq:
 816  *    struct.to_h -> hash
 817  *
 818  * Create a hash from member names and struct values.
 819  */
 820 static mrb_value
 821 mrb_struct_to_h(mrb_state *mrb, mrb_value self)
 822 {
 823   mrb_value members, ret;
 824   mrb_int i;
 825
 826   members = mrb_struct_s_members(mrb, mrb_obj_value(mrb_class(mrb, self)));
 827   ret = mrb_hash_new_capa(mrb, RARRAY_LEN(members));
 828
 829   for (i = 0; i < RARRAY_LEN(members); ++i) {
 830     mrb_hash_set(mrb, ret, RARRAY_PTR(members)[i], RSTRUCT_PTR(self)[i]);
 831   }
 832
 833   return ret;
 834 }
 835
 836 static mrb_value
 837 mrb_struct_values_at(mrb_state *mrb, mrb_value self)
 838 {
 839   mrb_int argc;
 840   mrb_value *argv;
 841
 842   mrb_get_args(mrb, "*", &argv, &argc);
 843
 844   return mrb_get_values_at(mrb, self, RSTRUCT_LEN(self), argc, argv, struct_aref_int);
 845 }
 846
 847 /*
 848  *  A <code>Struct</code> is a convenient way to bundle a number of
 849  *  attributes together, using accessor methods, without having to write
 850  *  an explicit class.
 851  *
 852  *  The <code>Struct</code> class is a generator of specific classes,
 853  *  each one of which is defined to hold a set of variables and their
 854  *  accessors. In these examples, we'll call the generated class
 855  *  ``<i>Customer</i>Class,'' and we'll show an example instance of that
 856  *  class as ``<i>Customer</i>Inst.''
 857  *
 858  *  In the descriptions that follow, the parameter <i>symbol</i> refers
 859  *  to a symbol, which is either a quoted string or a
 860  *  <code>Symbol</code> (such as <code>:name</code>).
 861  */
 862 void
 863 mrb_mruby_struct_gem_init(mrb_state* mrb)
 864 {
 865   struct RClass *st;
 866   st = mrb_define_class(mrb, "Struct",  mrb->object_class);
 867
 868   mrb_define_class_method(mrb, st, "new",             mrb_struct_s_def,       MRB_ARGS_ANY());  /* 15.2.18.3.1  */
 869
 870   mrb_define_method(mrb, st,       "==",              mrb_struct_equal,       MRB_ARGS_REQ(1)); /* 15.2.18.4.1  */
 871   mrb_define_method(mrb, st,       "[]",              mrb_struct_aref,        MRB_ARGS_REQ(1)); /* 15.2.18.4.2  */
 872   mrb_define_method(mrb, st,       "[]=",             mrb_struct_aset,        MRB_ARGS_REQ(2)); /* 15.2.18.4.3  */
 873   mrb_define_method(mrb, st,       "members",         mrb_struct_members_m,   MRB_ARGS_NONE()); /* 15.2.18.4.6  */
 874   mrb_define_method(mrb, st,       "initialize",      mrb_struct_initialize_m,MRB_ARGS_ANY());  /* 15.2.18.4.8  */
 875   mrb_define_method(mrb, st,       "initialize_copy", mrb_struct_init_copy,   MRB_ARGS_REQ(1)); /* 15.2.18.4.9  */
 876   mrb_define_method(mrb, st,       "inspect",         mrb_struct_inspect,     MRB_ARGS_NONE()); /* 15.2.18.4.10(x)  */
 877   mrb_define_alias(mrb, st,        "to_s", "inspect");                                      /* 15.2.18.4.11(x)  */
 878   mrb_define_method(mrb, st,       "eql?",            mrb_struct_eql,         MRB_ARGS_REQ(1)); /* 15.2.18.4.12(x)  */
 879
 880   mrb_define_method(mrb, st,        "size",           mrb_struct_len,         MRB_ARGS_NONE());
 881   mrb_define_method(mrb, st,        "length",         mrb_struct_len,         MRB_ARGS_NONE());
 882   mrb_define_method(mrb, st,        "to_a",           mrb_struct_to_a,        MRB_ARGS_NONE());
 883   mrb_define_method(mrb, st,        "values",         mrb_struct_to_a,        MRB_ARGS_NONE());
 884   mrb_define_method(mrb, st,        "to_h",           mrb_struct_to_h,        MRB_ARGS_NONE());
 885   mrb_define_method(mrb, st,        "values_at",      mrb_struct_values_at,   MRB_ARGS_NONE());
 886 }
 887
 888 void
 889 mrb_mruby_struct_gem_final(mrb_state* mrb)
 890 {
 891 }