lib/ringbuf.h

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Circular buffer implementation.
   4  * Copyright (C) 2017 Cumulus Networks
   5  * Quentin Young
   6  */
   7 #ifndef _FRR_RINGBUF_H_
   8 #define _FRR_RINGBUF_H_
   9
  10 #include <zebra.h>
  11 #include <stdint.h>
  12
  13 #include "memory.h"
  14
  15 #ifdef __cplusplus
  16 extern "C" {
  17 #endif
  18
  19 struct ringbuf {
  20         size_t size;
  21         ssize_t start;
  22         ssize_t end;
  23         bool empty;
  24         uint8_t *data;
  25 };
  26
  27 /*
  28  * Creates a new ring buffer.
  29  *
  30  * @param size  buffer size, in bytes
  31  * @return the newly created buffer
  32  */
  33 struct ringbuf *ringbuf_new(size_t size);
  34
  35 /*
  36  * Deletes a ring buffer and frees all associated resources.
  37  *
  38  * @param buf   the ring buffer to destroy
  39  */
  40 void ringbuf_del(struct ringbuf *buf);
  41
  42 /*
  43  * Get amount of data left to read from the buffer.
  44  *
  45  * @return number of readable bytes
  46  */
  47 size_t ringbuf_remain(struct ringbuf *buf);
  48
  49 /*
  50  * Get amount of space left to write to the buffer
  51  *
  52  * @return number of writeable bytes
  53  */
  54 size_t ringbuf_space(struct ringbuf *buf);
  55
  56
  57 /*
  58  * Put data into the ring buffer.
  59  *
  60  * @param data  the data to put in the buffer
  61  * @param size  how much of data to put in
  62  * @return number of bytes written; will be less than size if there was not
  63  * enough space
  64  */
  65 size_t ringbuf_put(struct ringbuf *buf, const void *data, size_t size);
  66
  67 /*
  68  * Get data from the ring buffer.
  69  *
  70  * @param data  where to put the data
  71  * @param size  how much of data to get
  72  * @return number of bytes read into data; will be less than size if there was
  73  * not enough data to read
  74  */
  75 size_t ringbuf_get(struct ringbuf *buf, void *data, size_t size);
  76
  77 /*
  78  * Peek data from the ring buffer.
  79  *
  80  * @param offset        where to get the data from, in bytes offset from the
  81  *                      start of the data
  82  * @param data          where to put the data
  83  * @param size          how much data to get
  84  * @return              number of bytes read into data; will be less than size
  85  *                      if there was not enough data to read; will be -1 if the
  86  *                      offset exceeds the amount of data left in the ring
  87  *                      buffer
  88  */
  89 size_t ringbuf_peek(struct ringbuf *buf, size_t offset, void *data,
  90                     size_t size);
  91
  92 /*
  93  * Copy data from one ringbuf to another.
  94  *
  95  * @param to    destination ringbuf
  96  * @param from  source ringbuf
  97  * @param size  how much data to copy
  98  * @return amount of data copied
  99  */
 100 size_t ringbuf_copy(struct ringbuf *to, struct ringbuf *from, size_t size);
 101
 102 /*
 103  * Reset buffer. Does not wipe.
 104  *
 105  * @param buf
 106  */
 107 void ringbuf_reset(struct ringbuf *buf);
 108
 109 /*
 110  * Reset buffer. Wipes.
 111  *
 112  * @param buf
 113  */
 114 void ringbuf_wipe(struct ringbuf *buf);
 115
 116 #ifdef __cplusplus
 117 }
 118 #endif
 119
 120 #endif /* _FRR_RINGBUF_H_ */