#ifndef BHLIB_IO_H
#define BHLIB_IO_H

#include "bh.h"

#define BH_IO_ERROR (1 << 0)
#define BH_IO_EOF   (1 << 1)

#define BH_IO_CAST(x) \
    ((bh_io_t *)(x))

struct bh_io_s;

typedef struct bh_io_table_s
{
    size_t (*read)(struct bh_io_s *io,
                   char *data,
                   size_t size);

    size_t (*write)(struct bh_io_s *io,
                    const char *data,
                    size_t size);

    void (*flush)(struct bh_io_s *io);

    void (*seek)(struct bh_io_s *io,
                 bh_off_t offset,
                 int dir);

    bh_off_t (*tell)(struct bh_io_s *io);

    bh_off_t (*available)(struct bh_io_s *io);

    void (*clear)(struct bh_io_s *io);

    void (*destroy)(struct bh_io_s *io);
} bh_io_table_t;

typedef struct bh_io_s
{
    bh_io_table_t *table;
    int flags;
} bh_io_t;

/**
 * @brief   Create new IO object.
 *
 * @param   table   Valid pointer to the IO table.
 * @param   size    Size of the IO object.
 *
 * @return  If the function succeeds, the return value is a pointer to the
 *          new, semi-initalized, IO object.
 * @return  If the function fails, the return value is NULL.
 *
 * @warning This function should be used in context of implementing child
 *          IO objects (files, sockets, streaming compression, etc).
 *
 * @sa      bh_io_free
 */
bh_io_t *bh_io_new(bh_io_table_t *table,
                   size_t size);

/**
 * @brief   Free IO object.
 *
 * @param   io      Valid pointer to the IO object.
 */
void bh_io_free(bh_io_t *io);

/**
 * @brief   Read data from IO.
 *
 * @param   io      Valid pointer to the IO object.
 * @param   data    Valid pointer to the buffer.
 * @param   size    Size of the buffer.
 *
 * @return  If the function succeeds, the return value is the amount
 *          of bytes read from the IO object.
 * @return  If the function fails, the return value is zero and error
 *          flag is set.
 *
 * @sa      bh_io_write, bh_io_eof, bh_io_error
 */
size_t bh_io_read(bh_io_t *io,
                  char *data,
                  size_t size);

/**
 * @brief   Write data to IO.
 *
 * @param   io      Valid pointer to the IO object.
 * @param   data    Valid pointer to the buffer.
 * @param   size    Size of the buffer.
 *
 * @return  If the function succeeds, the return value is the amount
 *          of bytes written to the IO object.
 * @return  If the function fails, the return value is zero and error
 *          flag is set.
 *
 * @sa      bh_io_read, bh_io_error, bh_io_flush
 */
size_t bh_io_write(bh_io_t *io,
                   const char* data,
                   size_t size);

/**
 * @brief   Writes any uncommited changes (if possible).
 *
 * @param   io      Valid pointer to the IO object.
 */
void bh_io_flush(bh_io_t *io);

/**
 * @brief   Seeks IO object to the specified position (if possible).
 *
 * @param   io      Valid pointer to the IO object.
 * @param   offset  Position
 * @param   dir     Direction
 *
 * @sa      bh_io_tell
 */
void bh_io_seek(bh_io_t *io,
                bh_off_t offset,
                int dir);

/**
 * @brief   Return current position in IO.
 *
 * @param   io      Valid pointer to the IO object.
 *
 * @return  If the function succeeds, the return value is current 
 *          position in the IO.
 * @return  If the function fails, the return value is -1.
 * 
 * @sa      bh_io_seek
 */
bh_off_t bh_io_tell(bh_io_t *io);

/**
 * @brief   Return available bytes in the IO.
 *
 * @param   io      Valid pointer to the IO object.
 *
 * @return  If the function succeeds, the return value is the amount
 *          of the available bytes for reading.
 * @return  If the function fails, the return value is zero.
 */
bh_off_t bh_io_available(bh_io_t *io);

/**
 * @brief   Return error flag of the IO.
 *
 * @param   io      Valid pointer to the IO object.
 * 
 * @return  The return value is error flag.
 *
 * @sa      bh_io_eof, bh_io_clear
 */
int bh_io_error(bh_io_t *io);

/**
 * @brief   Return end-of-file flag of the IO.
 *
 * @param   io      Valid pointer to the IO object.
 *
 * @return  The return value is end-of-file flag.
 *
 * @sa      bh_io_error, bh_io_clear
 */
int bh_io_eof(bh_io_t *io);

/**
 * @brief   Crear IO object state.
 *
 * @param   io      Valid pointer to the IO object.
 *
 * @sa      bh_io_error, bh_io_eof
 */
void bh_io_clear(bh_io_t *io);


#endif /* BHLIB_IO_H */