libosmovty  0.9.6-17.20170220git32ee5af8.an8
Osmocom VTY library
buffer.h
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., 51 Franklin Street, Fifth Floor,
20  * Boston, MA 02110-1301, USA.
21  */
22 
23 #pragma once
24 
25 #include <sys/types.h>
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 struct buffer *buffer_new(void *ctx, size_t);
31 
32 /* Free all data in the buffer. */
33 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 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 *, unsigned 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  /* An I/O error occurred. The buffer should be destroyed and the
57  file descriptor should be closed. */
58  BUFFER_ERROR = -1,
59 
60  /* The data was written successfully, and the buffer is now empty
61  (there is no pending data waiting to be flushed). */
62  BUFFER_EMPTY = 0,
63 
64  /* There is pending data in the buffer waiting to be flushed. Please
65  try flushing the buffer when select indicates that the file descriptor
66  is writeable. */
67  BUFFER_PENDING = 1
68 } buffer_status_t;
69 
70 /* Try to write this data to the file descriptor. Any data that cannot
71  be written immediately is added to the buffer queue. */
72 extern buffer_status_t buffer_write(struct buffer *, int fd,
73  const void *, size_t);
74 
75 /* This function attempts to flush some (but perhaps not all) of
76  the queued data to the given file descriptor. */
77 extern buffer_status_t buffer_flush_available(struct buffer *, int fd);
78 
79 /* The following 2 functions (buffer_flush_all and buffer_flush_window)
80  are for use in lib/vty.c only. They should not be used elsewhere. */
81 
82 /* Call buffer_flush_available repeatedly until either all data has been
83  flushed, or an I/O error has been encountered, or the operation would
84  block. */
85 extern buffer_status_t buffer_flush_all(struct buffer *, int fd);
86 
87 /* Attempt to write enough data to the given fd to fill a window of the
88  given width and height (and remove the data written from the buffer).
89 
90  If !no_more, then a message saying " --More-- " is appended.
91  If erase is true, then first overwrite the previous " --More-- " message
92  with spaces.
93 
94  Any write error (including EAGAIN or EINTR) will cause this function
95  to return -1 (because the logic for handling the erase and more features
96  is too complicated to retry the write later).
97 */
98 extern buffer_status_t buffer_flush_window(struct buffer *, int fd, int width,
99  int height, int erase, int no_more);
Definition: buffer.c:36