Returns a hash value based on this
struct’s contents (see 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);
}