#ifndef LIB_URING_H
#define LIB_URING_H

#include <sys/uio.h>
#include <signal.h>
#include <string.h>
#include "../../include/uapi/linux/io_uring.h"

/*
 * Library interface to io_uring
 */
struct io_uring_sq {
	unsigned *khead;
	unsigned *ktail;
	unsigned *kring_mask;
	unsigned *kring_entries;
	unsigned *kflags;
	unsigned *kdropped;
	unsigned *array;
	struct io_uring_sqe *sqes;

	unsigned sqe_head;
	unsigned sqe_tail;

	size_t ring_sz;
};

struct io_uring_cq {
	unsigned *khead;
	unsigned *ktail;
	unsigned *kring_mask;
	unsigned *kring_entries;
	unsigned *koverflow;
	struct io_uring_cqe *cqes;

	size_t ring_sz;
};

struct io_uring {
	struct io_uring_sq sq;
	struct io_uring_cq cq;
	int ring_fd;
};

/*
 * System calls
 */
extern int io_uring_setup(unsigned entries, struct io_uring_params *p);
extern int io_uring_enter(unsigned fd, unsigned to_submit,
	unsigned min_complete, unsigned flags, sigset_t *sig);
extern int io_uring_register(int fd, unsigned int opcode, void *arg,
	unsigned int nr_args);

/*
 * Library interface
 */
extern int io_uring_queue_init(unsigned entries, struct io_uring *ring,
	unsigned flags);
extern int io_uring_queue_mmap(int fd, struct io_uring_params *p,
	struct io_uring *ring);
extern void io_uring_queue_exit(struct io_uring *ring);
extern int io_uring_get_completion(struct io_uring *ring,
	struct io_uring_cqe **cqe_ptr);
extern int io_uring_wait_completion(struct io_uring *ring,
	struct io_uring_cqe **cqe_ptr);
extern int io_uring_submit(struct io_uring *ring);
extern struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring);

/*
 * Command prep helpers
 */
static inline void io_uring_sqe_set_data(struct io_uring_sqe *sqe, void *data)
{
	sqe->user_data = (unsigned long) data;
}

static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
				    void *addr, unsigned len, off_t offset)
{
	memset(sqe, 0, sizeof(*sqe));
	sqe->opcode = op;
	sqe->fd = fd;
	sqe->off = offset;
	sqe->addr = (unsigned long) addr;
	sqe->len = len;
}

static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
				       struct iovec *iovecs, unsigned nr_vecs,
				       off_t offset)
{
	io_uring_prep_rw(IORING_OP_READV, sqe, fd, iovecs, nr_vecs, offset);
}

static inline void io_uring_prep_read_fixed(struct io_uring_sqe *sqe, int fd,
					    void *buf, unsigned nbytes,
					    off_t offset)
{
	io_uring_prep_rw(IORING_OP_READ_FIXED, sqe, fd, buf, nbytes, offset);
}

static inline void io_uring_prep_writev(struct io_uring_sqe *sqe, int fd,
				        struct iovec *iovecs, unsigned nr_vecs,
					off_t offset)
{
	io_uring_prep_rw(IORING_OP_WRITEV, sqe, fd, iovecs, nr_vecs, offset);
}

static inline void io_uring_prep_write_fixed(struct io_uring_sqe *sqe, int fd,
					     void *buf, unsigned nbytes,
					     off_t offset)
{
	io_uring_prep_rw(IORING_OP_WRITE_FIXED, sqe, fd, buf, nbytes, offset);
}

static inline void io_uring_prep_poll_add(struct io_uring_sqe *sqe, int fd,
					  short poll_mask)
{
	memset(sqe, 0, sizeof(*sqe));
	sqe->opcode = IORING_OP_POLL_ADD;
	sqe->fd = fd;
	sqe->poll_events = poll_mask;
}

static inline void io_uring_prep_poll_remove(struct io_uring_sqe *sqe,
					     void *user_data)
{
	memset(sqe, 0, sizeof(*sqe));
	sqe->opcode = IORING_OP_POLL_REMOVE;
	sqe->addr = (unsigned long) user_data;
}

static inline void io_uring_prep_fsync(struct io_uring_sqe *sqe, int fd,
				       int datasync)
{
	memset(sqe, 0, sizeof(*sqe));
	sqe->opcode = IORING_OP_FSYNC;
	sqe->fd = fd;
	if (datasync)
		sqe->fsync_flags = IORING_FSYNC_DATASYNC;
}

#endif