/*
    Copyright (C) 2008 Andreas Baumann <abaumann@yahoo.com>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "port/time.h"

#if !defined HAVE_LOCALTIME_R || defined TEST_LOCALTIME_R

#if defined HAVE_PTHREADS

#include <pthread.h>		/* for pthread_X */

#include "port/stdbool.h"	/* for bool */
#include "port/string.h"	/* for memcpy */

struct tm *wolf_port_localtime_r( const time_t *timep, struct tm *result ) {
	static pthread_mutex_t mutex;
	static bool first = true;
	struct tm *local_result;

	if( first ) {
		pthread_mutex_init( &mutex, NULL );
		first = false;
	}

	pthread_mutex_lock( &mutex );
	local_result = localtime( timep );
	if( local_result != NULL ) {
		memcpy( result, local_result, sizeof( struct tm ) );
	}
	pthread_mutex_unlock( &mutex );

	return ( local_result != NULL ) ? result : NULL;
}

#else /* defined HAVE_PTHREADS */

#if defined _WIN32

/* localtime on Windows uses thread-local data to make things thread-safe,
 * see MinGW mailing-lists. So we can safely copy the local buffer to the
 * result without locking.
 * TODO: needs testing of the hypothesis!
 */

#include "port/string.h"	/* for memcpy */

struct tm *wolf_port_localtime_r( const time_t *timep, struct tm *result ) {
	struct tm *local_result;

	local_result = localtime( timep );
	if( local_result != NULL ) {
		memcpy( result, local_result, sizeof( struct tm ) );
	}

	return ( local_result != NULL ) ? result : NULL;
}

#else
#error no pthreads, port localtime_r differently!
#endif /* defined _WIN32 */

#endif /* defined HAVE_PTHREADS */

#endif /* !defined HAVE_LOCALTIME_R || defined TEST_LOCALTIME_R */