Return a hash value based on this
struct’s contents.
static VALUE
rb_struct_hash(VALUE s)
{
long i, h;
VALUE n;
h = rb_hash(rb_obj_class(s));
for (i = 0; i < RSTRUCT_LEN(s); i++) {
h = (h << 1) | (h<0 ? 1 : 0);
n = rb_hash(RSTRUCT_PTR(s)[i]);
h ^= NUM2LONG(n);
}
return LONG2FIX(h);
}