Pack and Unpack methods in UVM

typedef enum{RED, GREEN, BLUE} color_type;

class temp_class extends uvm_object;
  rand bit [7:0] tmp_addr;
  rand bit [7:0] tmp_data;
  
  function new(string name = "temp_class");
    super.new(name);
  endfunction
  
  `uvm_object_utils(temp_class)
    
  function void do_print(uvm_printer printer);
    super.do_print(printer);
    printer.print_field_int("tmp_addr", tmp_addr, $bits(tmp_addr), UVM_HEX);
    printer.print_field_int("tmp_data", tmp_data, $bits(tmp_data), UVM_HEX);
  endfunction
  
  function void do_pack(uvm_packer packer);
    super.do_pack(packer);
    packer.pack_field_int(tmp_addr, $bits(tmp_addr));
    packer.pack_field_int(tmp_data, $bits(tmp_data));
  endfunction
  
  function void do_unpack(uvm_packer packer);
    super.do_unpack(packer);
    tmp_addr = packer.unpack_field_int($bits(tmp_addr));
    tmp_data = packer.unpack_field_int($bits(tmp_data));
  endfunction
endclass

class my_object extends uvm_object;
  rand int        value;
  rand color_type colors;
  rand byte       data[4];
  rand bit [7:0]  addr;
  rand temp_class tmp;
  
  `uvm_object_utils(my_object)
  
  function new(string name = "my_object");
    super.new(name);
    tmp = new();
  endfunction
  
  function void do_print(uvm_printer printer);
    super.do_print(printer);
    printer.print_field_int("value", value, $bits(value), UVM_HEX);
    printer.print_string("colors", colors.name);
    foreach(data[i])
      printer.print_field_int($sformatf("data[%0d]", i), data[i], $bits(data[i]), UVM_HEX);
    printer.print_field_int("addr", addr, $bits(addr), UVM_HEX);
    printer.print_object("tmp", tmp);
  endfunction
  
  function void do_pack(uvm_packer packer);
    super.do_pack(packer);
    packer.pack_field_int(value, $bits(value));
    packer.pack_field_int(colors, $bits(colors));
    foreach(data[i])
      packer.pack_field_int(data[i], $bits(data[i]));
    packer.pack_field_int(addr, $bits(addr));
    packer.pack_object(tmp);
  endfunction
  
  function void do_unpack(uvm_packer packer);
    super.do_unpack(packer);
    value = packer.unpack_field_int($bits(value));
    colors = packer.unpack_field_int($bits(colors));
    foreach(data[i])
      data[i] = packer.unpack_field_int($bits(data[i]));
    addr = packer.unpack_field_int($bits(addr));
    packer.unpack_object(tmp);
  endfunction
endclass

class my_test extends uvm_test;
  `uvm_component_utils(my_test)
  my_object obj;
  bit packed_data_bits[];
  byte unsigned packed_data_bytes[];
  int unsigned packed_data_ints[];
  
  my_object unpack_obj;
  
  int pack_values[3];
  int unpack_values[3];
  
  function new(string name = "my_test", uvm_component parent = null);
    super.new(name, parent);
  endfunction
  
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    obj = my_object::type_id::create("obj", this);
    assert(obj.randomize());
    `uvm_info(get_full_name(), $sformatf("obj = \n%s", obj.sprint()), UVM_LOW);
    
    // pack methods
    pack_values[0] = obj.pack(packed_data_bits);
    pack_values[1] = obj.pack_bytes(packed_data_bytes);
    pack_values[2] = obj.pack_ints(packed_data_ints);
    `uvm_info(get_full_name(), $sformatf("packed_data_bits = %p", packed_data_bits), UVM_LOW);
    `uvm_info(get_full_name(), $sformatf("packed_data_bytes = %p", packed_data_bytes), UVM_LOW);
    `uvm_info(get_full_name(), $sformatf("packed_data_ints = %p", packed_data_ints), UVM_LOW);
    `uvm_info(get_full_name(), $sformatf("pack_values[BITS] = %0d, pack_values[BYTES] = %0d, pack_values[INTS] = %0d", pack_values[0], pack_values[1], pack_values[2]), UVM_LOW);
    // unpack methods
    unpack_obj = my_object::type_id::create("unpack_obj", this);
    unpack_values[0] = unpack_obj.unpack(packed_data_bits);
    `uvm_info(get_full_name(), $sformatf("bits: unpack_obj = \n%s", unpack_obj.sprint()), UVM_LOW);
    unpack_values[1] = unpack_obj.unpack_bytes(packed_data_bytes);
    `uvm_info(get_full_name(), $sformatf("bytes: unpack_obj = \n%s", unpack_obj.sprint()), UVM_LOW);
    unpack_values[2] = unpack_obj.unpack_ints(packed_data_ints);
    `uvm_info(get_full_name(), $sformatf("ints: unpack_obj = \n%s", unpack_obj.sprint()), UVM_LOW);
    `uvm_info(get_full_name(), $sformatf("unpack_values[BITS] = %0d, unpack_values[BYTES] = %0d, unpack_values[INTS] = %0d", unpack_values[0], unpack_values[1], unpack_values[2]), UVM_LOW);
  endfunction
endclass

module tb_top;
  initial begin
    run_test("my_test");
  end
endmodule