#ifndef _BATCH_QUEUE_COMMON_COMM_H_
#define _BATCH_QUEUE_COMMON_COMM_H_ 1

#include <stdint.h>
#include <unistd.h>

/* Non standard include */
#include <commtech.h>

#ifndef BUF_SIZE
#define BUF_SIZE (32 * CACHE_LINE_SIZE)
#endif

struct channel
{
	/* buf must be the first field to allow the buf_mask test */
	void * volatile buf[2][BUF_SIZE / sizeof(void *)] __attribute__ ((aligned (CACHE_LINE_SIZE)));
	struct channel *mapping1; /* accesses to buf[0] and state */
	struct channel *mapping2; /* accesses to buf[1] */
	uintptr_t buf_mask;
	int unused[20] __attribute__ ((aligned (CACHE_LINE_SIZE)));
	volatile unsigned int  state:1 __attribute__ ((aligned (CACHE_LINE_SIZE)));
	void * volatile *sender_ptr __attribute__ ((aligned (CACHE_LINE_SIZE)));
	void * volatile *receiver_ptr __attribute__ ((aligned (CACHE_LINE_SIZE)));
};

#ifndef _BATCH_QUEUE_C_
#ifndef PAGE_SIZE_HELPER
#define PAGE_SIZE_HELPER 1
uintptr_t _bq_page_mask;
void *create_comm_channel_internal(void);
static void *create_comm_channel_helper(void) __attribute__ ((unused));

static void *create_comm_channel_helper(void)
{
	int ret;
	struct channel *channel;

	ret = sysconf(_SC_PAGESIZE);
	if (ret == -1)
		return NULL;
	_bq_page_mask = ~(ret - 1);
	channel = create_comm_channel_internal();
	channel->buf_mask = sizeof channel->buf[0] - 1;
	return channel;
}

#else
extern unsigned int _bq_page_mask;
#endif /* PAGE_SIZE_HELPER */

#define create_comm_channel() create_comm_channel_helper()

__BEGIN_DECLS

static inline void send(struct channel *channel, void **addr)
{
	uintptr_t sender_ptr_high;

	*channel->sender_ptr++ = addr;
	if (unlikely(!((uintptr_t) channel->sender_ptr & channel->buf_mask)))
	{
		while (channel->state);
		channel->state = 1;
		sender_ptr_high =
			(uintptr_t) channel->sender_ptr & _bq_page_mask;
		if ((void *) sender_ptr_high == channel->mapping1)
			channel->sender_ptr = channel->mapping2->buf[1];
		else
			channel->sender_ptr = channel->mapping1->buf[0];
	}
}

__END_DECLS

#endif /* _BATCH_QUEUE_C_ */

#endif