lib/ringbuf.h

   1 /*
   2  * Circular buffer implementation.
   3  * Copyright (C) 2017 Cumulus Networks
   4  * Quentin Young
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20 #ifndef _FRR_RINGBUF_H_
  21 #define _FRR_RINGBUF_H_
  22
  23 #include <zebra.h>
  24 #include <stdint.h>
  25
  26 #include "memory.h"
  27
  28 #ifdef __cplusplus
  29 extern "C" {
  30 #endif
  31
  32 struct ringbuf {
  33         size_t size;
  34         ssize_t start;
  35         ssize_t end;
  36         bool empty;
  37         uint8_t *data;
  38 };
  39
  40 /*
  41  * Creates a new ring buffer.
  42  *
  43  * @param size  buffer size, in bytes
  44  * @return the newly created buffer
  45  */
  46 struct ringbuf *ringbuf_new(size_t size);
  47
  48 /*
  49  * Deletes a ring buffer and frees all associated resources.
  50  *
  51  * @param buf   the ring buffer to destroy
  52  */
  53 void ringbuf_del(struct ringbuf *buf);
  54
  55 /*
  56  * Get amount of data left to read from the buffer.
  57  *
  58  * @return number of readable bytes
  59  */
  60 size_t ringbuf_remain(struct ringbuf *buf);
  61
  62 /*
  63  * Get amount of space left to write to the buffer
  64  *
  65  * @return number of writeable bytes
  66  */
  67 size_t ringbuf_space(struct ringbuf *buf);
  68
  69
  70 /*
  71  * Put data into the ring buffer.
  72  *
  73  * @param data  the data to put in the buffer
  74  * @param size  how much of data to put in
  75  * @return number of bytes written; will be less than size if there was not
  76  * enough space
  77  */
  78 size_t ringbuf_put(struct ringbuf *buf, const void *data, size_t size);
  79
  80 /*
  81  * Get data from the ring buffer.
  82  *
  83  * @param data  where to put the data
  84  * @param size  how much of data to get
  85  * @return number of bytes read into data; will be less than size if there was
  86  * not enough data to read
  87  */
  88 size_t ringbuf_get(struct ringbuf *buf, void *data, size_t size);
  89
  90 /*
  91  * Peek data from the ring buffer.
  92  *
  93  * @param offset        where to get the data from, in bytes offset from the
  94  *                      start of the data
  95  * @param data          where to put the data
  96  * @param size          how much data to get
  97  * @return              number of bytes read into data; will be less than size
  98  *                      if there was not enough data to read; will be -1 if the
  99  *                      offset exceeds the amount of data left in the ring
 100  *                      buffer
 101  */
 102 size_t ringbuf_peek(struct ringbuf *buf, size_t offset, void *data,
 103                     size_t size);
 104
 105 /*
 106  * Copy data from one ringbuf to another.
 107  *
 108  * @param to    destination ringbuf
 109  * @param from  source ringbuf
 110  * @param size  how much data to copy
 111  * @return amount of data copied
 112  */
 113 size_t ringbuf_copy(struct ringbuf *to, struct ringbuf *from, size_t size);
 114
 115 /*
 116  * Reset buffer. Does not wipe.
 117  *
 118  * @param buf
 119  */
 120 void ringbuf_reset(struct ringbuf *buf);
 121
 122 /*
 123  * Reset buffer. Wipes.
 124  *
 125  * @param buf
 126  */
 127 void ringbuf_wipe(struct ringbuf *buf);
 128
 129 #ifdef __cplusplus
 130 }
 131 #endif
 132
 133 #endif /* _FRR_RINGBUF_H_ */