#ifndef KVM__DISK_IMAGE_H
#define KVM__DISK_IMAGE_H

#include <stdint.h>
#include <stdbool.h>
#include <sys/uio.h>

#define SECTOR_SHIFT		9
#define SECTOR_SIZE		(1UL << SECTOR_SHIFT)

struct disk_image;

struct disk_image_operations {
	int (*read_sector)(struct disk_image *self, uint64_t sector, void *dst, uint32_t dst_len);
	int (*write_sector)(struct disk_image *self, uint64_t sector, void *src, uint32_t src_len);
	ssize_t (*read_sector_sg)(struct disk_image *self, uint64_t sector, const struct iovec *iov, int iovcount);
	ssize_t (*write_sector_sg)(struct disk_image *self, uint64_t sector, const struct iovec *iov, int iovcount);
	void (*close)(struct disk_image *self);
};

struct disk_image {
	int				fd;
	uint64_t			size;
	struct disk_image_operations	*ops;
	void				*priv;
};

struct disk_image *disk_image__open(const char *filename, bool readonly);
struct disk_image *disk_image__new(int fd, uint64_t size, struct disk_image_operations *ops);
struct disk_image *disk_image__new_readonly(int fd, uint64_t size, struct disk_image_operations *ops);
void disk_image__close(struct disk_image *self);

static inline int disk_image__read_sector(struct disk_image *self, uint64_t sector, void *dst, uint32_t dst_len)
{
	return self->ops->read_sector(self, sector, dst, dst_len);
}

static inline int disk_image__write_sector(struct disk_image *self, uint64_t sector, void *src, uint32_t src_len)
{
	return self->ops->write_sector(self, sector, src, src_len);
}

static inline ssize_t disk_image__read_sector_sg(struct disk_image *self, uint64_t sector, const struct iovec *iov, int iovcount)
{
	if (self->ops->read_sector_sg)
		return self->ops->read_sector_sg(self, sector, iov, iovcount);

	while (iovcount--) {
		self->ops->read_sector(self, sector, iov->iov_base, iov->iov_len);
		sector += iov->iov_len >> SECTOR_SHIFT;
		iov++;
	}

	return sector << SECTOR_SHIFT;
}

static inline ssize_t disk_image__write_sector_sg(struct disk_image *self, uint64_t sector, const struct iovec *iov, int iovcount)
{
	if (self->ops->write_sector_sg)
		return self->ops->write_sector_sg(self, sector, iov, iovcount);

	while (iovcount--) {
		self->ops->write_sector(self, sector, iov->iov_base, iov->iov_len);
		sector += iov->iov_len >> SECTOR_SHIFT;
		iov++;
	}

	return sector << SECTOR_SHIFT;
}

#endif /* KVM__DISK_IMAGE_H */