//----------------------------------------------------------------------

// class: uvm_config_db

//

// All of the functions in uvm_config_db#(T) are static, so they

// must be called using the :: operator.  For example:

//

//|  uvm_config_db#(int)::set(this, "*", "A");

//

// The parameter value "int" identifies the configuration type as

// an int property.

//

// The <set> and <get> methods provide the same API and

// semantics as the set/get_config_* functions in <uvm_component>.

//----------------------------------------------------------------------

class uvm_config_db#(type T=int) extends uvm_resource_db#(T);

  // Internal lookup of config settings so they can be reused

  // The context has a pool that is keyed by the inst/field name.

  static uvm_pool#(string,uvm_resource#(T)) m_rsc[uvm_component];

  // Internal waiter list for wait_modified

  static local uvm_queue#(m_uvm_waiter) m_waiters[string];

  // function: get

  //

  // Get the value for ~field_name~ in ~inst_name~, using component ~cntxt~ as

  // the starting search point. ~inst_name~ is an explicit instance name

  // relative to ~cntxt~ and may be an empty string if the ~cntxt~ is the

  // instance that the configuration object applies to. ~field_name~

  // is the specific field in the scope that is being searched for.

  //

  // The basic ~get_config_*~ methods from <uvm_component> are mapped to

  // this function as:

  //

  //| get_config_int(...) => uvm_config_db#(uvm_bitstream_t)::get(cntxt,...)

  //| get_config_string(...) => uvm_config_db#(string)::get(cntxt,...)

  //| get_config_object(...) => uvm_config_db#(uvm_object)::get(cntxt,...)

  static function bit get(uvm_component cntxt,

                          string inst_name,

                          string field_name,

                          inout T value);

//TBD: add file/line

    int unsigned p;

    uvm_resource#(T) r, rt;

    uvm_resource_pool rp = uvm_resource_pool::get();

    uvm_resource_types::rsrc_q_t rq;

    uvm_coreservice_t cs = uvm_coreservice_t::get();

    if(cntxt == null)

      cntxt = cs.get_root();

    if(inst_name == "")

      inst_name = cntxt.get_full_name();

    else if(cntxt.get_full_name() != "")

      inst_name = {cntxt.get_full_name(), ".", inst_name};

    rq = rp.lookup_regex_names(inst_name, field_name, uvm_resource#(T)::get_type());

    r = uvm_resource#(T)::get_highest_precedence(rq);

    if(uvm_config_db_options::is_tracing())

      m_show_msg("CFGDB/GET", "Configuration","read", inst_name, field_name, cntxt, r);

    if(r == null)

      return ;

    value = r.read(cntxt);

    return ;

  endfunction

  // function: set

  //

  // Create a new or update an existing configuration setting for

  // ~field_name~ in ~inst_name~ from ~cntxt~.

  // The setting is made at ~cntxt~, with the full scope of the set

  // being {~cntxt~,".",~inst_name~}. If ~cntxt~ is ~null~ then ~inst_name~

  // provides the complete scope information of the setting.

  // ~field_name~ is the target field. Both ~inst_name~ and ~field_name~

  // may be glob style or regular expression style expressions.

  //

  // If a setting is made at build time, the ~cntxt~ hierarchy is

  // used to determine the setting's precedence in the database.

  // Settings from hierarchically higher levels have higher

  // precedence. Settings from the same level of hierarchy have

  // a last setting wins semantic. A precedence setting of

  // <uvm_resource_base::default_precedence>  is used for uvm_top, and

  // each hierarchical level below the top is decremented by 1.

  //

  // After build time, all settings use the default precedence and thus

  // have a last wins semantic. So, if at run time, a low level

  // component makes a runtime setting of some field, that setting

  // will have precedence over a setting from the test level that was

  // made earlier in the simulation.

  //

  // The basic ~set_config_*~ methods from <uvm_component> are mapped to

  // this function as:

  //

  //| set_config_int(...) => uvm_config_db#(uvm_bitstream_t)::set(cntxt,...)

  //| set_config_string(...) => uvm_config_db#(string)::set(cntxt,...)

  //| set_config_object(...) => uvm_config_db#(uvm_object)::set(cntxt,...)

  static function void set(uvm_component cntxt,

                           string inst_name,

                           string field_name,

                           T value);

    uvm_root top;

    uvm_phase curr_phase;

    uvm_resource#(T) r;

    bit exists;

    string lookup;

    uvm_pool#(string,uvm_resource#(T)) pool;

    string rstate;

    uvm_coreservice_t cs = uvm_coreservice_t::get();

    //take care of random stability during allocation

    process p = process::self();

    if(p != null)

          rstate = p.get_randstate();

    top = cs.get_root();

    curr_phase = top.m_current_phase;

    if(cntxt == null)

      cntxt = top;

    if(inst_name == "")

      inst_name = cntxt.get_full_name();

    else if(cntxt.get_full_name() != "")

      inst_name = {cntxt.get_full_name(), ".", inst_name};

    if(!m_rsc.exists(cntxt)) begin

      m_rsc[cntxt] = new;

    end

    pool = m_rsc[cntxt];

    // Insert the token in the middle to prevent cache

    // oddities like i=foobar,f=xyz and i=foo,f=barxyz.

    // Can't just use '.', because '.' isn't illegal

    // in field names

    lookup = {inst_name, "__M_UVM__", field_name};

    if(!pool.exists(lookup)) begin

       r = new(field_name, inst_name);

       pool.add(lookup, r);

    end

    else begin

      r = pool.get(lookup);

      exists = ;

    end

    if(curr_phase != null && curr_phase.get_name() == "build")

      r.precedence = uvm_resource_base::default_precedence - (cntxt.get_depth());

    else

      r.precedence = uvm_resource_base::default_precedence;

    r.write(value, cntxt);

    if(exists) begin

      uvm_resource_pool rp = uvm_resource_pool::get();

      rp.set_priority_name(r, uvm_resource_types::PRI_HIGH);

    end

    else begin

      //Doesn't exist yet, so put it in resource db at the head.

      r.set_override();

    end

    //trigger any waiters

    if(m_waiters.exists(field_name)) begin

      m_uvm_waiter w;

      for(int i=; i<m_waiters[field_name].size(); ++i) begin

        w = m_waiters[field_name].get(i);

        if(uvm_re_match(uvm_glob_to_re(inst_name),w.inst_name) == )

           ->w.trigger;

      end

    end

    if(p != null)

        p.set_randstate(rstate);

    if(uvm_config_db_options::is_tracing())

      m_show_msg("CFGDB/SET", "Configuration","set", inst_name, field_name, cntxt, r);

  endfunction

  // function: exists

  //

  // Check if a value for ~field_name~ is available in ~inst_name~, using

  // component ~cntxt~ as the starting search point. ~inst_name~ is an explicit

  // instance name relative to ~cntxt~ and may be an empty string if the

  // ~cntxt~ is the instance that the configuration object applies to.

  // ~field_name~ is the specific field in the scope that is being searched for.

  // The ~spell_chk~ arg can be set to 1 to turn spell checking on if it

  // is expected that the field should exist in the database. The function

  // returns 1 if a config parameter exists and 0 if it doesn't exist.

  //

  static function bit exists(uvm_component cntxt, string inst_name,

    string field_name, bit spell_chk=);

    uvm_coreservice_t cs = uvm_coreservice_t::get();

    if(cntxt == null)

      cntxt = cs.get_root();

    if(inst_name == "")

      inst_name = cntxt.get_full_name();

    else if(cntxt.get_full_name() != "")

      inst_name = {cntxt.get_full_name(), ".", inst_name};

    return (uvm_resource_db#(T)::get_by_name(inst_name,field_name,spell_chk) != null);

  endfunction

  // Function: wait_modified

  //

  // Wait for a configuration setting to be set for ~field_name~

  // in ~cntxt~ and ~inst_name~. The task blocks until a new configuration

  // setting is applied that effects the specified field.

  static task wait_modified(uvm_component cntxt, string inst_name,

      string field_name);

    process p = process::self();

    string rstate = p.get_randstate();

    m_uvm_waiter waiter;

    uvm_coreservice_t cs = uvm_coreservice_t::get();

    if(cntxt == null)

      cntxt = cs.get_root();

    if(cntxt != cs.get_root()) begin

      if(inst_name != "")

        inst_name = {cntxt.get_full_name(),".",inst_name};

      else

        inst_name = cntxt.get_full_name();

    end

    waiter = new(inst_name, field_name);

    if(!m_waiters.exists(field_name))

      m_waiters[field_name] = new;

    m_waiters[field_name].push_back(waiter);

    p.set_randstate(rstate);

    // wait on the waiter to trigger

    @waiter.trigger;

    // Remove the waiter from the waiter list

    for(int i=; i<m_waiters[field_name].size(); ++i) begin

      if(m_waiters[field_name].get(i) == waiter) begin

        m_waiters[field_name].delete(i);

        break;

      end

    end

  endtask

endclass