nbbio.h

[詳解]

#ifndef _NBBIO_H_INCLUDED_
#define _NBBIO_H_INCLUDED_

/*++
/* NAME
/*  nbbio 3h
/* SUMMARY
/*  non-blocking buffered I/O
/* SYNOPSIS
/*  #include "nbbio.h"
/* DESCRIPTION
/* .nf

 /*
  * Utility library.
  */
#include <events.h>         /* Needed for EVENT_READ etc. */

 /*
  * External interface. All structure members are private.
  */
typedef void (*NBBIO_ACTION) (int, void *);

typedef struct {
    int     fd;             /* socket file descriptor */
    ssize_t bufsize;            /* read/write buffer size */
    char   *label;          /* diagnostics */
    NBBIO_ACTION action;        /* call-back routine */
    void   *context;            /* call-back context */
    int     flags;          /* buffer-pair status */

    char   *read_buf;           /* start of buffer */
    ssize_t read_pend;          /* nr of unread bytes */

    char   *write_buf;          /* start of buffer */
    ssize_t write_pend;         /* nr of unwritten bytes */
} NBBIO;

#define NBBIO_FLAG_READ     (1<<0)
#define NBBIO_FLAG_WRITE    (1<<1)
#define NBBIO_FLAG_EOF      (1<<2)
#define NBBIO_FLAG_ERROR    (1<<3)
#define NBBIO_FLAG_TIMEOUT  (1<<4)

#define NBBIO_OP_NAME(np) \
    (((np)->flags & NBBIO_FLAG_READ) ? "read" : \
     ((np)->flags & NBBIO_FLAG_WRITE) ? "write" : \
     "unknown")

#define NBBIO_MASK_ACTIVE \
    (NBBIO_FLAG_READ | NBBIO_FLAG_WRITE)

#define NBBIO_MASK_ERROR \
    (NBBIO_FLAG_EOF | NBBIO_FLAG_ERROR | NBBIO_FLAG_TIMEOUT)

#define NBBIO_BUFSIZE(np)       (((np)->bufsize) + 0)   /* Read-only */

#define NBBIO_READ_PEND(np)     ((np)->read_pend)
#define NBBIO_READ_BUF(np)      ((np)->read_buf + 0)    /* Read-only */

#define NBBIO_WRITE_PEND(np)        ((np)->write_pend)
#define NBBIO_WRITE_BUF(np)     ((np)->write_buf + 0)   /* Read-only */

#define NBBIO_ACTIVE_FLAGS(np)      ((np)->flags & NBBIO_MASK_ACTIVE)
#define NBBIO_ERROR_FLAGS(np)       ((np)->flags & NBBIO_MASK_ERROR)

extern NBBIO *nbbio_create(int, ssize_t, const char *, NBBIO_ACTION, void *);
extern void nbbio_free(NBBIO *);
extern void nbbio_enable_read(NBBIO *, int);
extern void nbbio_enable_write(NBBIO *, int);
extern void nbbio_disable_readwrite(NBBIO *);
extern void nbbio_slumber(NBBIO *, int);

/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*--*/

#endif