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quagga

    1: /*
    2:  * Buffering to output and input. 
    3:  * Copyright (C) 1998 Kunihiro Ishiguro
    4:  *
    5:  * This file is part of GNU Zebra.
    6:  *
    7:  * GNU Zebra is free software; you can redistribute it and/or modify
    8:  * it under the terms of the GNU General Public License as published
    9:  * by the Free Software Foundation; either version 2, or (at your
   10:  * option) any later version.
   11:  *
   12:  * GNU Zebra is distributed in the hope that it will be useful, but
   13:  * WITHOUT ANY WARRANTY; without even the implied warranty of
   14:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   15:  * General Public License for more details.
   16:  *
   17:  * You should have received a copy of the GNU General Public License
   18:  * along with GNU Zebra; see the file COPYING.  If not, write to the
   19:  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   20:  * Boston, MA 02111-1307, USA.
   21:  */
   22: 
   23: #ifndef _ZEBRA_BUFFER_H
   24: #define _ZEBRA_BUFFER_H
   25: 
   26: 
   27: /* Create a new buffer.  Memory will be allocated in chunks of the given
   28:    size.  If the argument is 0, the library will supply a reasonable
   29:    default size suitable for buffering socket I/O. */
   30: extern struct buffer *buffer_new (size_t);
   31: 
   32: /* Free all data in the buffer. */
   33: extern void buffer_reset (struct buffer *);
   34: 
   35: /* This function first calls buffer_reset to release all buffered data.
   36:    Then it frees the struct buffer itself. */
   37: extern void buffer_free (struct buffer *);
   38: 
   39: /* Add the given data to the end of the buffer. */
   40: extern void buffer_put (struct buffer *, const void *, size_t);
   41: /* Add a single character to the end of the buffer. */
   42: extern void buffer_putc (struct buffer *, u_char);
   43: /* Add a NUL-terminated string to the end of the buffer. */
   44: extern void buffer_putstr (struct buffer *, const char *);
   45: 
   46: /* Combine all accumulated (and unflushed) data inside the buffer into a
   47:    single NUL-terminated string allocated using XMALLOC(MTYPE_TMP).  Note
   48:    that this function does not alter the state of the buffer, so the data
   49:    is still inside waiting to be flushed. */
   50: char *buffer_getstr (struct buffer *);
   51: 
   52: /* Returns 1 if there is no pending data in the buffer.  Otherwise returns 0. */
   53: int buffer_empty (struct buffer *);
   54: 
   55: typedef enum
   56:   {
   57:     /* An I/O error occurred.  The buffer should be destroyed and the
   58:        file descriptor should be closed. */
   59:     BUFFER_ERROR = -1,
   60: 
   61:     /* The data was written successfully, and the buffer is now empty
   62:        (there is no pending data waiting to be flushed). */
   63:     BUFFER_EMPTY = 0,
   64: 
   65:     /* There is pending data in the buffer waiting to be flushed.  Please
   66:        try flushing the buffer when select indicates that the file descriptor
   67:        is writeable. */
   68:     BUFFER_PENDING = 1
   69:   } buffer_status_t;
   70: 
   71: /* Try to write this data to the file descriptor.  Any data that cannot
   72:    be written immediately is added to the buffer queue. */
   73: extern buffer_status_t buffer_write(struct buffer *, int fd,
   74: 				    const void *, size_t);
   75: 
   76: /* This function attempts to flush some (but perhaps not all) of 
   77:    the queued data to the given file descriptor. */
   78: extern buffer_status_t buffer_flush_available(struct buffer *, int fd);
   79: 
   80: /* The following 2 functions (buffer_flush_all and buffer_flush_window)
   81:    are for use in lib/vty.c only.  They should not be used elsewhere. */
   82: 
   83: /* Call buffer_flush_available repeatedly until either all data has been
   84:    flushed, or an I/O error has been encountered, or the operation would
   85:    block. */
   86: extern buffer_status_t buffer_flush_all (struct buffer *, int fd);
   87: 
   88: /* Attempt to write enough data to the given fd to fill a window of the
   89:    given width and height (and remove the data written from the buffer).
   90: 
   91:    If !no_more, then a message saying " --More-- " is appended. 
   92:    If erase is true, then first overwrite the previous " --More-- " message
   93:    with spaces.
   94: 
   95:    Any write error (including EAGAIN or EINTR) will cause this function
   96:    to return -1 (because the logic for handling the erase and more features
   97:    is too complicated to retry the write later).
   98: */
   99: extern buffer_status_t buffer_flush_window (struct buffer *, int fd, int width,
  100: 					    int height, int erase, int no_more);
  101: 
  102: #endif /* _ZEBRA_BUFFER_H */