/*****************************************************************************

  The following code is derived, directly or indirectly, from the SystemC
  source code Copyright (c) 1996-2002 by all Contributors.
  All Rights reserved.

  The contents of this file are subject to the restrictions and limitations
  set forth in the SystemC Open Source License Version 2.3 (the "License");
  You may not use this file except in compliance with such restrictions and
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 *****************************************************************************/

/*****************************************************************************

  sc_semaphore.cpp -- The sc_semaphore primitive channel class.

  Original Author: Martin Janssen, Synopsys, Inc., 2001-05-21

 *****************************************************************************/

/*****************************************************************************

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

      Name, Affiliation, Date:
  Description of Modification:
    
 *****************************************************************************/


#include "systemc/communication/sc_communication_ids.h"
#include "systemc/communication/sc_semaphore.h"
#include "systemc/kernel/sc_simcontext.h"


// ----------------------------------------------------------------------------
//  CLASS : sc_semaphore
//
//  The sc_semaphore primitive channel class.
// ----------------------------------------------------------------------------

const char* const sc_semaphore::kind_string = "sc_semaphore";


// error reporting

void
sc_semaphore::report_error( int id, const char* add_msg ) const
{
    char msg[BUFSIZ];
    if( add_msg != 0 ) {
	sprintf( msg, "%s: semaphore '%s'", add_msg, name() );
    } else {
	sprintf( msg, "semaphore '%s'", name() );
    }
    SC_REPORT_ERROR( id, msg );
}


// constructors

sc_semaphore::sc_semaphore( int init_value_ )
: sc_prim_channel( sc_gen_unique_name( "semaphore" ) ),
  m_value( init_value_ )
{
    if( m_value < 0 ) {
	report_error( SC_ID_INVALID_SEMAPHORE_VALUE_ );
    }
}

sc_semaphore::sc_semaphore( const char* name_, int init_value_ )
: sc_prim_channel( name_ ), m_value( init_value_ )
{
    if( m_value < 0 ) {
	report_error( SC_ID_INVALID_SEMAPHORE_VALUE_ );
    }
}


// interface methods

// lock (take) the semaphore, block if not available

int
sc_semaphore::wait()
{
    while( in_use() ) {
	sc_prim_channel::wait( m_free );
    }
    -- m_value;
    return 0;
}


// lock (take) the semaphore, return -1 if not available

int
sc_semaphore::trywait()
{
    if( in_use() ) {
	return -1;
    }
    -- m_value;
    return 0;
}


// unlock (give) the semaphore

int
sc_semaphore::post()
{
    ++ m_value;
    m_free.notify();
    return 0;
}


// Taf!
