/* 
 * Copyright 2010 Stefan Lankes, Chair for Operating Systems,
 *                               RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file is part of MetalSVM.
 */

#ifndef __MAILBOX_H__
#define __MAILBOX_H__

#include <metalsvm/string.h>
#include <metalsvm/mailbox_types.h>
#include <metalsvm/tasks.h>
#include <metalsvm/semaphore.h>

#ifdef __cplusplus
extern "C" {
#endif

#define MAILBOX(name, type) 	\
	inline static int mailbox_##name##_init(mailbox_##name##_t* m) { \
		if (BUILTIN_EXPECT(!m, 0)) \
			return -1; \
	\
		memset(m->buffer, 0x00, sizeof(type)*MAILBOX_SIZE); \
		m->wpos = m->rpos = 0; \
		sem_init(&m->mails, 0); \
		sem_init(&m->boxes, MAILBOX_SIZE); \
		spinlock_init(&m->rlock); \
		spinlock_init(&m->wlock); \
	\
		return 0; \
	}\
	\
	inline static int mailbox_##name##_destroy(mailbox_##name##_t* m) { \
		if (BUILTIN_EXPECT(!m, 0)) \
			return -1; \
	\
		sem_destroy(&m->mails); \
		sem_destroy(&m->boxes); \
		spinlock_destroy(&m->rlock); \
		spinlock_destroy(&m->wlock); \
	\
		return 0; \
	} \
	\
	inline static int mailbox_##name##_post(mailbox_##name##_t* m, type mail) { \
		if (BUILTIN_EXPECT(!m, 0)) \
			return -1; \
	\
		sem_wait(&m->boxes); \
		spinlock_lock(&m->wlock); \
		m->buffer[m->wpos] = mail; \
		m->wpos = (m->wpos+1) % MAILBOX_SIZE; \
		spinlock_unlock(&m->wlock); \
		sem_post(&m->mails); \
	\
		return 0; \
	} \
	\
	inline static int mailbox_##name##_fetch(mailbox_##name##_t* m, type* mail) { \
		if (BUILTIN_EXPECT(!m || !mail, 0)) \
			return -1; \
	\
		sem_wait(&m->mails); \
		spinlock_lock(&m->rlock); \
		*mail = m->buffer[m->rpos]; \
		m->rpos = (m->rpos+1) % MAILBOX_SIZE; \
		spinlock_unlock(&m->rlock); \
		sem_post(&m->boxes); \
	\
		return 0; \
	} \
	\
	inline static int mailbox_##name##_tryfetch(mailbox_##name##_t* m, type* mail) { \
		if (BUILTIN_EXPECT(!m || !mail, 0)) \
			return -1; \
	\
		if (sem_trywait(&m->mails) != 0) \
			return -1; \
		spinlock_lock(&m->rlock); \
		*mail = m->buffer[m->rpos]; \
		m->rpos = (m->rpos+1) % MAILBOX_SIZE; \
		spinlock_unlock(&m->rlock); \
		sem_post(&m->boxes); \
	\
		return 0; \
	}\

MAILBOX(wait_msg, wait_msg_t)
MAILBOX(int32, int32_t)
MAILBOX(int16, int16_t)
MAILBOX(int8, int8_t)
MAILBOX(uint32, uint32_t)
MAILBOX(uint16, uint16_t)
MAILBOX(uint8, uint8_t)
MAILBOX(ptr, void*)

#ifdef __cplusplus
}
#endif

#endif