Fresh start

1 files changed, 1104 insertions, 0 deletions

diff --git a/jni/ruby/struct.c b/jni/ruby/struct.c
new file mode 100644
index 0000000..35f618e
--- /dev/null
+++ b/jni/ruby/struct.c
@@ -0,0 +1,1104 @@
+/**********************************************************************
+
+  struct.c -
+
+  $Author: nobu $
+  created at: Tue Mar 22 18:44:30 JST 1995
+
+  Copyright (C) 1993-2007 Yukihiro Matsumoto
+
+**********************************************************************/
+
+#include "internal.h"
+#include "vm_core.h"
+#include "method.h"
+
+VALUE rb_method_for_self_aref(VALUE name, VALUE arg, rb_insn_func_t func);
+VALUE rb_method_for_self_aset(VALUE name, VALUE arg, rb_insn_func_t func);
+
+VALUE rb_cStruct;
+static ID id_members;
+
+static VALUE struct_alloc(VALUE);
+
+static inline VALUE
+struct_ivar_get(VALUE c, ID id)
+{
+    for (;;) {
+	if (rb_ivar_defined(c, id))
+	    return rb_ivar_get(c, id);
+	c = RCLASS_SUPER(c);
+	if (c == 0 || c == rb_cStruct)
+	    return Qnil;
+    }
+}
+
+VALUE
+rb_struct_s_members(VALUE klass)
+{
+    VALUE members = struct_ivar_get(klass, id_members);
+
+    if (NIL_P(members)) {
+	rb_raise(rb_eTypeError, "uninitialized struct");
+    }
+    if (!RB_TYPE_P(members, T_ARRAY)) {
+	rb_raise(rb_eTypeError, "corrupted struct");
+    }
+    return members;
+}
+
+VALUE
+rb_struct_members(VALUE s)
+{
+    VALUE members = rb_struct_s_members(rb_obj_class(s));
+
+    if (RSTRUCT_LEN(s) != RARRAY_LEN(members)) {
+	rb_raise(rb_eTypeError, "struct size differs (%ld required %ld given)",
+		 RARRAY_LEN(members), RSTRUCT_LEN(s));
+    }
+    return members;
+}
+
+static VALUE
+rb_struct_s_members_m(VALUE klass)
+{
+    VALUE members = rb_struct_s_members(klass);
+
+    return rb_ary_dup(members);
+}
+
+/*
+ *  call-seq:
+ *     struct.members    -> array
+ *
+ *  Returns the struct members as an array of symbols:
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joe.members   #=> [:name, :address, :zip]
+ */
+
+static VALUE
+rb_struct_members_m(VALUE obj)
+{
+    return rb_struct_s_members_m(rb_obj_class(obj));
+}
+
+NORETURN(static void not_a_member(ID id));
+static void
+not_a_member(ID id)
+{
+    rb_name_error(id, "`%"PRIsVALUE"' is not a struct member", QUOTE_ID(id));
+}
+
+VALUE
+rb_struct_getmember(VALUE obj, ID id)
+{
+    VALUE members, slot;
+    long i, len;
+
+    members = rb_struct_members(obj);
+    slot = ID2SYM(id);
+    len = RARRAY_LEN(members);
+    for (i=0; i<len; i++) {
+	if (RARRAY_AREF(members, i) == slot) {
+	    return RSTRUCT_GET(obj, i);
+	}
+    }
+    not_a_member(id);
+
+    UNREACHABLE;
+}
+
+static VALUE rb_struct_ref0(VALUE obj) {return RSTRUCT_GET(obj, 0);}
+static VALUE rb_struct_ref1(VALUE obj) {return RSTRUCT_GET(obj, 1);}
+static VALUE rb_struct_ref2(VALUE obj) {return RSTRUCT_GET(obj, 2);}
+static VALUE rb_struct_ref3(VALUE obj) {return RSTRUCT_GET(obj, 3);}
+static VALUE rb_struct_ref4(VALUE obj) {return RSTRUCT_GET(obj, 4);}
+static VALUE rb_struct_ref5(VALUE obj) {return RSTRUCT_GET(obj, 5);}
+static VALUE rb_struct_ref6(VALUE obj) {return RSTRUCT_GET(obj, 6);}
+static VALUE rb_struct_ref7(VALUE obj) {return RSTRUCT_GET(obj, 7);}
+static VALUE rb_struct_ref8(VALUE obj) {return RSTRUCT_GET(obj, 8);}
+static VALUE rb_struct_ref9(VALUE obj) {return RSTRUCT_GET(obj, 9);}
+
+#define N_REF_FUNC numberof(ref_func)
+
+static VALUE (*const ref_func[])(VALUE) = {
+    rb_struct_ref0,
+    rb_struct_ref1,
+    rb_struct_ref2,
+    rb_struct_ref3,
+    rb_struct_ref4,
+    rb_struct_ref5,
+    rb_struct_ref6,
+    rb_struct_ref7,
+    rb_struct_ref8,
+    rb_struct_ref9,
+};
+
+static void
+rb_struct_modify(VALUE s)
+{
+    rb_check_frozen(s);
+    rb_check_trusted(s);
+}
+
+static VALUE
+anonymous_struct(VALUE klass)
+{
+    VALUE nstr;
+
+    nstr = rb_class_new(klass);
+    rb_make_metaclass(nstr, RBASIC(klass)->klass);
+    rb_class_inherited(klass, nstr);
+    return nstr;
+}
+
+static VALUE
+new_struct(VALUE name, VALUE super)
+{
+    /* old style: should we warn? */
+    ID id;
+    name = rb_str_to_str(name);
+    if (!rb_is_const_name(name)) {
+	rb_name_error_str(name, "identifier %"PRIsVALUE" needs to be constant",
+			  QUOTE(name));
+    }
+    id = rb_to_id(name);
+    if (rb_const_defined_at(super, id)) {
+	rb_warn("redefining constant %"PRIsVALUE"::%"PRIsVALUE, super, name);
+	rb_mod_remove_const(super, ID2SYM(id));
+    }
+    return rb_define_class_id_under(super, id, super);
+}
+
+static void
+define_aref_method(VALUE nstr, VALUE name, VALUE off)
+{
+    rb_control_frame_t *FUNC_FASTCALL(rb_vm_opt_struct_aref)(rb_thread_t *, rb_control_frame_t *);
+    VALUE iseqval = rb_method_for_self_aref(name, off, rb_vm_opt_struct_aref);
+    rb_iseq_t *iseq = DATA_PTR(iseqval);
+
+    rb_add_method(nstr, SYM2ID(name), VM_METHOD_TYPE_ISEQ, iseq, NOEX_PUBLIC);
+    RB_GC_GUARD(iseqval);
+}
+
+static void
+define_aset_method(VALUE nstr, VALUE name, VALUE off)
+{
+    rb_control_frame_t *FUNC_FASTCALL(rb_vm_opt_struct_aset)(rb_thread_t *, rb_control_frame_t *);
+    VALUE iseqval = rb_method_for_self_aset(name, off, rb_vm_opt_struct_aset);
+    rb_iseq_t *iseq = DATA_PTR(iseqval);
+
+    rb_add_method(nstr, SYM2ID(name), VM_METHOD_TYPE_ISEQ, iseq, NOEX_PUBLIC);
+    RB_GC_GUARD(iseqval);
+}
+
+static VALUE
+setup_struct(VALUE nstr, VALUE members)
+{
+    const VALUE *ptr_members;
+    long i, len;
+
+    OBJ_FREEZE(members);
+    rb_ivar_set(nstr, id_members, members);
+
+    rb_define_alloc_func(nstr, struct_alloc);
+    rb_define_singleton_method(nstr, "new", rb_class_new_instance, -1);
+    rb_define_singleton_method(nstr, "[]", rb_class_new_instance, -1);
+    rb_define_singleton_method(nstr, "members", rb_struct_s_members_m, 0);
+    ptr_members = RARRAY_CONST_PTR(members);
+    len = RARRAY_LEN(members);
+    for (i=0; i< len; i++) {
+	ID id = SYM2ID(ptr_members[i]);
+	VALUE off = LONG2NUM(i);
+
+	if (i < N_REF_FUNC) {
+	    rb_define_method_id(nstr, id, ref_func[i], 0);
+	}
+	else {
+	    define_aref_method(nstr, ptr_members[i], off);
+	}
+	define_aset_method(nstr, ID2SYM(rb_id_attrset(id)), off);
+    }
+
+    return nstr;
+}
+
+VALUE
+rb_struct_alloc_noinit(VALUE klass)
+{
+    return struct_alloc(klass);
+}
+
+static VALUE
+struct_define_without_accessor(VALUE outer, const char *class_name, VALUE super, rb_alloc_func_t alloc, VALUE members)
+{
+    VALUE klass;
+
+    if (class_name) {
+	if (outer) {
+	    klass = rb_define_class_under(outer, class_name, super);
+	}
+	else {
+	    klass = rb_define_class(class_name, super);
+	}
+    }
+    else {
+	klass = anonymous_struct(super);
+    }
+
+    rb_ivar_set(klass, id_members, members);
+
+    if (alloc) {
+	rb_define_alloc_func(klass, alloc);
+    }
+    else {
+	rb_define_alloc_func(klass, struct_alloc);
+    }
+
+    return klass;
+}
+
+VALUE
+rb_struct_define_without_accessor_under(VALUE outer, const char *class_name, VALUE super, rb_alloc_func_t alloc, ...)
+{
+    va_list ar;
+    VALUE members;
+    char *name;
+
+    members = rb_ary_tmp_new(0);
+    va_start(ar, alloc);
+    while ((name = va_arg(ar, char*)) != NULL) {
+        rb_ary_push(members, ID2SYM(rb_intern(name)));
+    }
+    va_end(ar);
+    OBJ_FREEZE(members);
+
+    return struct_define_without_accessor(outer, class_name, super, alloc, members);
+}
+
+VALUE
+rb_struct_define_without_accessor(const char *class_name, VALUE super, rb_alloc_func_t alloc, ...)
+{
+    va_list ar;
+    VALUE members;
+    char *name;
+
+    members = rb_ary_tmp_new(0);
+    va_start(ar, alloc);
+    while ((name = va_arg(ar, char*)) != NULL) {
+        rb_ary_push(members, ID2SYM(rb_intern(name)));
+    }
+    va_end(ar);
+    OBJ_FREEZE(members);
+
+    return struct_define_without_accessor(0, class_name, super, alloc, members);
+}
+
+VALUE
+rb_struct_define(const char *name, ...)
+{
+    va_list ar;
+    VALUE st, ary;
+    char *mem;
+
+    ary = rb_ary_tmp_new(0);
+
+    va_start(ar, name);
+    while ((mem = va_arg(ar, char*)) != 0) {
+	ID slot = rb_intern(mem);
+	rb_ary_push(ary, ID2SYM(slot));
+    }
+    va_end(ar);
+
+    if (!name) st = anonymous_struct(rb_cStruct);
+    else st = new_struct(rb_str_new2(name), rb_cStruct);
+    return setup_struct(st, ary);
+}
+
+VALUE
+rb_struct_define_under(VALUE outer, const char *name, ...)
+{
+    va_list ar;
+    VALUE ary;
+    char *mem;
+
+    ary = rb_ary_tmp_new(0);
+
+    va_start(ar, name);
+    while ((mem = va_arg(ar, char*)) != 0) {
+	ID slot = rb_intern(mem);
+	rb_ary_push(ary, ID2SYM(slot));
+    }
+    va_end(ar);
+
+    return setup_struct(rb_define_class_under(outer, name, rb_cStruct), ary);
+}
+
+/*
+ *  call-seq:
+ *    Struct.new([class_name] [, member_name]+>)                        -> StructClass
+ *    Struct.new([class_name] [, member_name]+>) {|StructClass| block } -> StructClass
+ *    StructClass.new(value, ...)                                       -> obj
+ *    StructClass[value, ...]                                           -> obj
+ *
+ *  The first two forms are used to create a new Struct subclass +class_name+
+ *  that can contain a value for each +member_name+.  This subclass can be
+ *  used to create instances of the structure like any other Class.
+ *
+ *  If the +class_name+ is omitted an anonymous structure class will be
+ *  created.  Otherwise, the name of this struct will appear as a constant in
+ *  class Struct, so it must be unique for all Structs in the system and
+ *  must start with a capital letter.  Assigning a structure class to a
+ *  constant also gives the class the name of the constant.
+ *
+ *     # Create a structure with a name under Struct
+ *     Struct.new("Customer", :name, :address)
+ *     #=> Struct::Customer
+ *     Struct::Customer.new("Dave", "123 Main")
+ *     #=> #<struct Struct::Customer name="Dave", address="123 Main">
+ *
+ *  If a block is given it will be evaluated in the context of
+ *  +StructClass+, passing the created class as a parameter:
+ *
+ *     Customer = Struct.new(:name, :address) do
+ *       def greeting
+ *         "Hello #{name}!"
+ *       end
+ *     end
+ *     Customer.new("Dave", "123 Main").greeting  # => "Hello Dave!"
+ *
+ *  This is the recommended way to customize a struct.  Subclassing an
+ *  anonymous struct creates an extra anonymous class that will never be used.
+ *
+ *  The last two forms create a new instance of a struct subclass.  The number
+ *  of +value+ parameters must be less than or equal to the number of
+ *  attributes defined for the structure.  Unset parameters default to +nil+.
+ *  Passing more parameters than number of attributes will raise
+ *  an ArgumentError.
+ *
+ *     # Create a structure named by its constant
+ *     Customer = Struct.new(:name, :address)
+ *     #=> Customer
+ *     Customer.new("Dave", "123 Main")
+ *     #=> #<struct Customer name="Dave", address="123 Main">
+ */
+
+static VALUE
+rb_struct_s_def(int argc, VALUE *argv, VALUE klass)
+{
+    VALUE name, rest;
+    long i;
+    VALUE st;
+    ID id;
+
+    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
+    name = argv[0];
+    if (SYMBOL_P(name)) {
+	name = Qnil;
+    }
+    else {
+	--argc;
+	++argv;
+    }
+    rest = rb_ary_tmp_new(argc);
+    for (i=0; i<argc; i++) {
+	id = rb_to_id(argv[i]);
+	RARRAY_ASET(rest, i, ID2SYM(id));
+	rb_ary_set_len(rest, i+1);
+    }
+    if (NIL_P(name)) {
+	st = anonymous_struct(klass);
+    }
+    else {
+	st = new_struct(name, klass);
+    }
+    setup_struct(st, rest);
+    if (rb_block_given_p()) {
+	rb_mod_module_eval(0, 0, st);
+    }
+
+    return st;
+}
+
+static long
+num_members(VALUE klass)
+{
+    VALUE members;
+    members = struct_ivar_get(klass, id_members);
+    if (!RB_TYPE_P(members, T_ARRAY)) {
+	rb_raise(rb_eTypeError, "broken members");
+    }
+    return RARRAY_LEN(members);
+}
+
+/*
+ */
+
+static VALUE
+rb_struct_initialize_m(int argc, const VALUE *argv, VALUE self)
+{
+    VALUE klass = rb_obj_class(self);
+    long i, n;
+
+    rb_struct_modify(self);
+    n = num_members(klass);
+    if (n < argc) {
+	rb_raise(rb_eArgError, "struct size differs");
+    }
+    for (i=0; i<argc; i++) {
+	RSTRUCT_SET(self, i, argv[i]);
+    }
+    if (n > argc) {
+	rb_mem_clear((VALUE *)RSTRUCT_CONST_PTR(self)+argc, n-argc);
+    }
+    return Qnil;
+}
+
+VALUE
+rb_struct_initialize(VALUE self, VALUE values)
+{
+    return rb_struct_initialize_m(RARRAY_LENINT(values), RARRAY_CONST_PTR(values), self);
+}
+
+static VALUE
+struct_alloc(VALUE klass)
+{
+    long n;
+    NEWOBJ_OF(st, struct RStruct, klass, T_STRUCT | (RGENGC_WB_PROTECTED_STRUCT ? FL_WB_PROTECTED : 0));
+
+    n = num_members(klass);
+
+    if (0 < n && n <= RSTRUCT_EMBED_LEN_MAX) {
+        RBASIC(st)->flags &= ~RSTRUCT_EMBED_LEN_MASK;
+        RBASIC(st)->flags |= n << RSTRUCT_EMBED_LEN_SHIFT;
+	rb_mem_clear((VALUE *)st->as.ary, n);
+    }
+    else {
+	st->as.heap.ptr = ALLOC_N(VALUE, n);
+	rb_mem_clear((VALUE *)st->as.heap.ptr, n);
+	st->as.heap.len = n;
+    }
+
+    return (VALUE)st;
+}
+
+VALUE
+rb_struct_alloc(VALUE klass, VALUE values)
+{
+    return rb_class_new_instance(RARRAY_LENINT(values), RARRAY_CONST_PTR(values), klass);
+}
+
+VALUE
+rb_struct_new(VALUE klass, ...)
+{
+    VALUE tmpargs[N_REF_FUNC], *mem = tmpargs;
+    int size, i;
+    va_list args;
+
+    size = rb_long2int(num_members(klass));
+    if (size > numberof(tmpargs)) {
+	tmpargs[0] = rb_ary_tmp_new(size);
+	mem = RARRAY_PTR(tmpargs[0]);
+    }
+    va_start(args, klass);
+    for (i=0; i<size; i++) {
+	mem[i] = va_arg(args, VALUE);
+    }
+    va_end(args);
+
+    return rb_class_new_instance(size, mem, klass);
+}
+
+static VALUE
+rb_struct_size(VALUE s);
+
+static VALUE
+struct_enum_size(VALUE s, VALUE args, VALUE eobj)
+{
+    return rb_struct_size(s);
+}
+
+/*
+ *  call-seq:
+ *     struct.each {|obj| block }  -> struct
+ *     struct.each                 -> an_enumerator
+ *
+ *  Yields the value of each struct member in order.  If no block is given an
+ *  enumerator is returned.
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joe.each {|x| puts(x) }
+ *
+ *  Produces:
+ *
+ *     Joe Smith
+ *     123 Maple, Anytown NC
+ *     12345
+ */
+
+static VALUE
+rb_struct_each(VALUE s)
+{
+    long i;
+
+    RETURN_SIZED_ENUMERATOR(s, 0, 0, struct_enum_size);
+    for (i=0; i<RSTRUCT_LEN(s); i++) {
+	rb_yield(RSTRUCT_GET(s, i));
+    }
+    return s;
+}
+
+/*
+ *  call-seq:
+ *     struct.each_pair {|sym, obj| block }     -> struct
+ *     struct.each_pair                         -> an_enumerator
+ *
+ *  Yields the name and value of each struct member in order.  If no block is
+ *  given an enumerator is returned.
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joe.each_pair {|name, value| puts("#{name} => #{value}") }
+ *
+ *  Produces:
+ *
+ *     name => Joe Smith
+ *     address => 123 Maple, Anytown NC
+ *     zip => 12345
+ */
+
+static VALUE
+rb_struct_each_pair(VALUE s)
+{
+    VALUE members;
+    long i;
+
+    RETURN_SIZED_ENUMERATOR(s, 0, 0, struct_enum_size);
+    members = rb_struct_members(s);
+    if (rb_block_arity() > 1) {
+	for (i=0; i<RSTRUCT_LEN(s); i++) {
+	    VALUE key = rb_ary_entry(members, i);
+	    VALUE value = RSTRUCT_GET(s, i);
+	    rb_yield_values(2, key, value);
+	}
+    }
+    else {
+	for (i=0; i<RSTRUCT_LEN(s); i++) {
+	    VALUE key = rb_ary_entry(members, i);
+	    VALUE value = RSTRUCT_GET(s, i);
+	    rb_yield(rb_assoc_new(key, value));
+	}
+    }
+    return s;
+}
+
+static VALUE
+inspect_struct(VALUE s, VALUE dummy, int recur)
+{
+    VALUE cname = rb_class_path(rb_obj_class(s));
+    VALUE members, str = rb_str_new2("#<struct ");
+    long i, len;
+    char first = RSTRING_PTR(cname)[0];
+
+    if (recur || first != '#') {
+	rb_str_append(str, cname);
+    }
+    if (recur) {
+	return rb_str_cat2(str, ":...>");
+    }
+
+    members = rb_struct_members(s);
+    len = RSTRUCT_LEN(s);
+
+    for (i=0; i<len; i++) {
+	VALUE slot;
+	ID id;
+
+	if (i > 0) {
+	    rb_str_cat2(str, ", ");
+	}
+	else if (first != '#') {
+	    rb_str_cat2(str, " ");
+	}
+	slot = RARRAY_AREF(members, i);
+	id = SYM2ID(slot);
+	if (rb_is_local_id(id) || rb_is_const_id(id)) {
+	    rb_str_append(str, rb_id2str(id));
+	}
+	else {
+	    rb_str_append(str, rb_inspect(slot));
+	}
+	rb_str_cat2(str, "=");
+	rb_str_append(str, rb_inspect(RSTRUCT_GET(s, i)));
+    }
+    rb_str_cat2(str, ">");
+    OBJ_INFECT(str, s);
+
+    return str;
+}
+
+/*
+ * call-seq:
+ *   struct.to_s      -> string
+ *   struct.inspect   -> string
+ *
+ * Describe the contents of this struct in a string.
+ */
+
+static VALUE
+rb_struct_inspect(VALUE s)
+{
+    return rb_exec_recursive(inspect_struct, s, 0);
+}
+
+/*
+ *  call-seq:
+ *     struct.to_a     -> array
+ *     struct.values   -> array
+ *
+ *  Returns the values for this struct as an Array.
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joe.to_a[1]   #=> "123 Maple, Anytown NC"
+ */
+
+static VALUE
+rb_struct_to_a(VALUE s)
+{
+    return rb_ary_new4(RSTRUCT_LEN(s), RSTRUCT_CONST_PTR(s));
+}
+
+/*
+ *  call-seq:
+ *     struct.to_h     -> hash
+ *
+ *  Returns a Hash containing the names and values for the struct's members.
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joe.to_h[:address]   #=> "123 Maple, Anytown NC"
+ */
+
+static VALUE
+rb_struct_to_h(VALUE s)
+{
+    VALUE h = rb_hash_new();
+    VALUE members = rb_struct_members(s);
+    long i;
+
+    for (i=0; i<RSTRUCT_LEN(s); i++) {
+	rb_hash_aset(h, rb_ary_entry(members, i), RSTRUCT_GET(s, i));
+    }
+    return h;
+}
+
+/* :nodoc: */
+VALUE
+rb_struct_init_copy(VALUE copy, VALUE s)
+{
+    long i, len;
+
+    if (!OBJ_INIT_COPY(copy, s)) return copy;
+    if (RSTRUCT_LEN(copy) != RSTRUCT_LEN(s)) {
+	rb_raise(rb_eTypeError, "struct size mismatch");
+    }
+
+    for (i=0, len=RSTRUCT_LEN(copy); i<len; i++) {
+	RSTRUCT_SET(copy, i, RSTRUCT_GET(s, i));
+    }
+
+    return copy;
+}
+
+static VALUE
+rb_struct_aref_sym(VALUE s, VALUE name)
+{
+    VALUE members = rb_struct_members(s);
+    long i, len = RARRAY_LEN(members);
+
+    for (i=0; i<len; i++) {
+	if (RARRAY_AREF(members, i) == name) {
+	    return RSTRUCT_GET(s, i);
+	}
+    }
+    rb_name_error_str(name, "no member '% "PRIsVALUE"' in struct", name);
+
+    UNREACHABLE;
+}
+
+/*
+ *  call-seq:
+ *     struct[member]   -> anObject
+ *     struct[index]    -> anObject
+ *
+ *  Attribute Reference---Returns the value of the given struct +member+ or
+ *  the member at the given +index+.   Raises NameError if the +member+ does
+ *  not exist and IndexError if the +index+ is out of range.
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *
+ *     joe["name"]   #=> "Joe Smith"
+ *     joe[:name]    #=> "Joe Smith"
+ *     joe[0]        #=> "Joe Smith"
+ */
+
+VALUE
+rb_struct_aref(VALUE s, VALUE idx)
+{
+    long i;
+
+    if (RB_TYPE_P(idx, T_SYMBOL)) {
+	return rb_struct_aref_sym(s, idx);
+    }
+    else if (RB_TYPE_P(idx, T_STRING)) {
+	ID id = rb_check_id(&idx);
+	if (!id) {
+	    rb_name_error_str(idx, "no member '%"PRIsVALUE"' in struct",
+			      QUOTE(idx));
+	}
+	return rb_struct_aref_sym(s, ID2SYM(id));
+    }
+
+    i = NUM2LONG(idx);
+    if (i < 0) i = RSTRUCT_LEN(s) + i;
+    if (i < 0)
+        rb_raise(rb_eIndexError, "offset %ld too small for struct(size:%ld)",
+		 i, RSTRUCT_LEN(s));
+    if (RSTRUCT_LEN(s) <= i)
+        rb_raise(rb_eIndexError, "offset %ld too large for struct(size:%ld)",
+		 i, RSTRUCT_LEN(s));
+    return RSTRUCT_GET(s, i);
+}
+
+static VALUE
+rb_struct_aset_sym(VALUE s, VALUE name, VALUE val)
+{
+    VALUE members = rb_struct_members(s);
+    long i, len = RARRAY_LEN(members);
+
+    if (RSTRUCT_LEN(s) != len) {
+	rb_raise(rb_eTypeError, "struct size differs (%ld required %ld given)",
+		 len, RSTRUCT_LEN(s));
+    }
+
+    for (i=0; i<len; i++) {
+	if (RARRAY_AREF(members, i) == name) {
+	    rb_struct_modify(s);
+	    RSTRUCT_SET(s, i, val);
+	    return val;
+	}
+    }
+    rb_name_error_str(name, "no member '% "PRIsVALUE"' in struct", name);
+
+    UNREACHABLE;
+}
+
+/*
+ *  call-seq:
+ *     struct[name]  = obj    -> obj
+ *     struct[index] = obj    -> obj
+ *
+ *  Attribute Assignment---Sets the value of the given struct +member+ or
+ *  the member at the given +index+.  Raises NameError if the +name+ does not
+ *  exist and IndexError if the +index+ is out of range.
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *
+ *     joe["name"] = "Luke"
+ *     joe[:zip]   = "90210"
+ *
+ *     joe.name   #=> "Luke"
+ *     joe.zip    #=> "90210"
+ */
+
+VALUE
+rb_struct_aset(VALUE s, VALUE idx, VALUE val)
+{
+    long i;
+
+    if (RB_TYPE_P(idx, T_SYMBOL)) {
+	return rb_struct_aset_sym(s, idx, val);
+    }
+    if (RB_TYPE_P(idx, T_STRING)) {
+	ID id = rb_check_id(&idx);
+	if (!id) {
+	    rb_name_error_str(idx, "no member '%"PRIsVALUE"' in struct",
+			      QUOTE(idx));
+	}
+	return rb_struct_aset_sym(s, ID2SYM(id), val);
+    }
+
+    i = NUM2LONG(idx);
+    if (i < 0) i = RSTRUCT_LEN(s) + i;
+    if (i < 0) {
+        rb_raise(rb_eIndexError, "offset %ld too small for struct(size:%ld)",
+		 i, RSTRUCT_LEN(s));
+    }
+    if (RSTRUCT_LEN(s) <= i) {
+        rb_raise(rb_eIndexError, "offset %ld too large for struct(size:%ld)",
+		 i, RSTRUCT_LEN(s));
+    }
+    rb_struct_modify(s);
+    RSTRUCT_SET(s, i, val);
+    return val;
+}
+
+static VALUE
+struct_entry(VALUE s, long n)
+{
+    return rb_struct_aref(s, LONG2NUM(n));
+}
+
+/*
+ *  call-seq:
+ *     struct.values_at(selector, ...)  -> an_array
+ *
+ *  Returns the struct member values for each +selector+ as an Array.  A
+ *  +selector+ may be either an Integer offset or a Range of offsets (as in
+ *  Array#values_at).
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joe.values_at 0, 2 #=> ["Joe Smith", 12345]
+ *
+ */
+
+static VALUE
+rb_struct_values_at(int argc, VALUE *argv, VALUE s)
+{
+    return rb_get_values_at(s, RSTRUCT_LEN(s), argc, argv, struct_entry);
+}
+
+/*
+ *  call-seq:
+ *     struct.select {|i| block }    -> array
+ *     struct.select                 -> an_enumerator
+ *
+ *  Yields each member value from the struct to the block and returns an Array
+ *  containing the member values from the +struct+ for which the given block
+ *  returns a true value (equivalent to Enumerable#select).
+ *
+ *     Lots = Struct.new(:a, :b, :c, :d, :e, :f)
+ *     l = Lots.new(11, 22, 33, 44, 55, 66)
+ *     l.select {|v| (v % 2).zero? }   #=> [22, 44, 66]
+ */
+
+static VALUE
+rb_struct_select(int argc, VALUE *argv, VALUE s)
+{
+    VALUE result;
+    long i;
+
+    rb_check_arity(argc, 0, 0);
+    RETURN_SIZED_ENUMERATOR(s, 0, 0, struct_enum_size);
+    result = rb_ary_new();
+    for (i = 0; i < RSTRUCT_LEN(s); i++) {
+	if (RTEST(rb_yield(RSTRUCT_GET(s, i)))) {
+	    rb_ary_push(result, RSTRUCT_GET(s, i));
+	}
+    }
+
+    return result;
+}
+
+static VALUE
+recursive_equal(VALUE s, VALUE s2, int recur)
+{
+    const VALUE *ptr, *ptr2;
+    long i, len;
+
+    if (recur) return Qtrue; /* Subtle! */
+    ptr = RSTRUCT_CONST_PTR(s);
+    ptr2 = RSTRUCT_CONST_PTR(s2);
+    len = RSTRUCT_LEN(s);
+    for (i=0; i<len; i++) {
+	if (!rb_equal(ptr[i], ptr2[i])) return Qfalse;
+    }
+    return Qtrue;
+}
+
+/*
+ *  call-seq:
+ *     struct == other     -> true or false
+ *
+ *  Equality---Returns +true+ if +other+ has the same struct subclass and has
+ *  equal member values (according to Object#==).
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe   = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joejr = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     jane  = Customer.new("Jane Doe", "456 Elm, Anytown NC", 12345)
+ *     joe == joejr   #=> true
+ *     joe == jane    #=> false
+ */
+
+static VALUE
+rb_struct_equal(VALUE s, VALUE s2)
+{
+    if (s == s2) return Qtrue;
+    if (!RB_TYPE_P(s2, T_STRUCT)) return Qfalse;
+    if (rb_obj_class(s) != rb_obj_class(s2)) return Qfalse;
+    if (RSTRUCT_LEN(s) != RSTRUCT_LEN(s2)) {
+	rb_bug("inconsistent struct"); /* should never happen */
+    }
+
+    return rb_exec_recursive_paired(recursive_equal, s, s2, s2);
+}
+
+/*
+ * call-seq:
+ *   struct.hash   -> fixnum
+ *
+ * Returns a hash value based on this struct's contents (see Object#hash).
+ *
+ * See also Object#hash.
+ */
+
+static VALUE
+rb_struct_hash(VALUE s)
+{
+    long i, len;
+    st_index_t h;
+    VALUE n;
+    const VALUE *ptr;
+
+    h = rb_hash_start(rb_hash(rb_obj_class(s)));
+    ptr = RSTRUCT_CONST_PTR(s);
+    len = RSTRUCT_LEN(s);
+    for (i = 0; i < len; i++) {
+	n = rb_hash(ptr[i]);
+	h = rb_hash_uint(h, NUM2LONG(n));
+    }
+    h = rb_hash_end(h);
+    return INT2FIX(h);
+}
+
+static VALUE
+recursive_eql(VALUE s, VALUE s2, int recur)
+{
+    const VALUE *ptr, *ptr2;
+    long i, len;
+
+    if (recur) return Qtrue; /* Subtle! */
+    ptr = RSTRUCT_CONST_PTR(s);
+    ptr2 = RSTRUCT_CONST_PTR(s2);
+    len = RSTRUCT_LEN(s);
+    for (i=0; i<len; i++) {
+	if (!rb_eql(ptr[i], ptr2[i])) return Qfalse;
+    }
+    return Qtrue;
+}
+
+/*
+ * call-seq:
+ *   struct.eql?(other)   -> true or false
+ *
+ * Hash equality---+other+ and +struct+ refer to the same hash key if they
+ * have the same struct subclass and have equal member values (according to
+ * Object#eql?).
+ */
+
+static VALUE
+rb_struct_eql(VALUE s, VALUE s2)
+{
+    if (s == s2) return Qtrue;
+    if (!RB_TYPE_P(s2, T_STRUCT)) return Qfalse;
+    if (rb_obj_class(s) != rb_obj_class(s2)) return Qfalse;
+    if (RSTRUCT_LEN(s) != RSTRUCT_LEN(s2)) {
+	rb_bug("inconsistent struct"); /* should never happen */
+    }
+
+    return rb_exec_recursive_paired(recursive_eql, s, s2, s2);
+}
+
+/*
+ *  call-seq:
+ *     struct.length    -> fixnum
+ *     struct.size      -> fixnum
+ *
+ *  Returns the number of struct members.
+ *
+ *     Customer = Struct.new(:name, :address, :zip)
+ *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
+ *     joe.length   #=> 3
+ */
+
+static VALUE
+rb_struct_size(VALUE s)
+{
+    return LONG2FIX(RSTRUCT_LEN(s));
+}
+
+/*
+ *  A Struct is a convenient way to bundle a number of attributes together,
+ *  using accessor methods, without having to write an explicit class.
+ *
+ *  The Struct class generates new subclasses that hold a set of members and
+ *  their values.  For each member a reader and writer method is created
+ *  similar to Module#attr_accessor.
+ *
+ *     Customer = Struct.new(:name, :address) do
+ *       def greeting
+ *         "Hello #{name}!"
+ *       end
+ *     end
+ *
+ *     dave = Customer.new("Dave", "123 Main")
+ *     dave.name     #=> "Dave"
+ *     dave.greeting #=> "Hello Dave!"
+ *
+ *  See Struct::new for further examples of creating struct subclasses and
+ *  instances.
+ *
+ *  In the method descriptions that follow a "member" parameter refers to a
+ *  struct member which is either a quoted string (<code>"name"</code>) or a
+ *  Symbol (<code>:name</code>).
+ */
+void
+InitVM_Struct(void)
+{
+    rb_cStruct = rb_define_class("Struct", rb_cObject);
+    rb_include_module(rb_cStruct, rb_mEnumerable);
+
+    rb_undef_alloc_func(rb_cStruct);
+    rb_define_singleton_method(rb_cStruct, "new", rb_struct_s_def, -1);
+
+    rb_define_method(rb_cStruct, "initialize", rb_struct_initialize_m, -1);
+    rb_define_method(rb_cStruct, "initialize_copy", rb_struct_init_copy, 1);
+
+    rb_define_method(rb_cStruct, "==", rb_struct_equal, 1);
+    rb_define_method(rb_cStruct, "eql?", rb_struct_eql, 1);
+    rb_define_method(rb_cStruct, "hash", rb_struct_hash, 0);
+
+    rb_define_method(rb_cStruct, "inspect", rb_struct_inspect, 0);
+    rb_define_alias(rb_cStruct,  "to_s", "inspect");
+    rb_define_method(rb_cStruct, "to_a", rb_struct_to_a, 0);
+    rb_define_method(rb_cStruct, "to_h", rb_struct_to_h, 0);
+    rb_define_method(rb_cStruct, "values", rb_struct_to_a, 0);
+    rb_define_method(rb_cStruct, "size", rb_struct_size, 0);
+    rb_define_method(rb_cStruct, "length", rb_struct_size, 0);
+
+    rb_define_method(rb_cStruct, "each", rb_struct_each, 0);
+    rb_define_method(rb_cStruct, "each_pair", rb_struct_each_pair, 0);
+    rb_define_method(rb_cStruct, "[]", rb_struct_aref, 1);
+    rb_define_method(rb_cStruct, "[]=", rb_struct_aset, 2);
+    rb_define_method(rb_cStruct, "select", rb_struct_select, -1);
+    rb_define_method(rb_cStruct, "values_at", rb_struct_values_at, -1);
+
+    rb_define_method(rb_cStruct, "members", rb_struct_members_m, 0);
+}
+
+#undef rb_intern
+void
+Init_Struct(void)
+{
+    id_members = rb_intern("__members__");
+
+    InitVM(Struct);
+}