initialize_copy

static VALUE
match_init_copy(VALUE obj, VALUE orig)
{
    struct rmatch *rm;

    if (obj == orig) return obj;

    if (!rb_obj_is_instance_of(orig, rb_obj_class(obj))) {
        rb_raise(rb_eTypeError, "wrong argument class");
    }
    RMATCH(obj)->str = RMATCH(orig)->str;
    RMATCH(obj)->regexp = RMATCH(orig)->regexp;

    rm = RMATCH(obj)->rmatch;
    onig_region_copy(&rm->regs, RMATCH_REGS(orig));

    if (!RMATCH(orig)->rmatch->char_offset_updated) {
        rm->char_offset_updated = 0;
    }
    else {
        if (rm->char_offset_num_allocated < rm->regs.num_regs) {
            REALLOC_N(rm->char_offset, struct rmatch_offset, rm->regs.num_regs);
            rm->char_offset_num_allocated = rm->regs.num_regs;
        }
        MEMCPY(rm->char_offset, RMATCH(orig)->rmatch->char_offset,
               struct rmatch_offset, rm->regs.num_regs);
        rm->char_offset_updated = 1;
    }

    return obj;
}