lib/ringbuffer/iterator.h

   1 #ifndef _LIB_RING_BUFFER_ITERATOR_H
   2 #define _LIB_RING_BUFFER_ITERATOR_H
   3
   4 /*
   5  * lib/ringbuffer/iterator.h
   6  *
   7  * Ring buffer and channel iterators.
   8  *
   9  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; only
  14  * version 2.1 of the License.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  *
  25  * Author:
  26  *      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  27  */
  28
  29 #include <wrapper/ringbuffer/backend.h>
  30 #include <wrapper/ringbuffer/frontend.h>
  31 #include <wrapper/ringbuffer/vfs.h>
  32
  33 /*
  34  * lib_ring_buffer_get_next_record advances the buffer read position to the next
  35  * record. It returns either the size of the next record, -EAGAIN if there is
  36  * currently no data available, or -ENODATA if no data is available and buffer
  37  * is finalized.
  38  */
  39 extern ssize_t lib_ring_buffer_get_next_record(struct channel *chan,
  40                                                struct lib_ring_buffer *buf);
  41
  42 /*
  43  * channel_get_next_record advances the buffer read position to the next record.
  44  * It returns either the size of the next record, -EAGAIN if there is currently
  45  * no data available, or -ENODATA if no data is available and buffer is
  46  * finalized.
  47  * Returns the current buffer in ret_buf.
  48  */
  49 extern ssize_t channel_get_next_record(struct channel *chan,
  50                                        struct lib_ring_buffer **ret_buf);
  51
  52 /**
  53  * read_current_record - copy the buffer current record into dest.
  54  * @buf: ring buffer
  55  * @dest: destination where the record should be copied
  56  *
  57  * dest should be large enough to contain the record. Returns the number of
  58  * bytes copied.
  59  */
  60 static inline size_t read_current_record(struct lib_ring_buffer *buf, void *dest)
  61 {
  62         return lib_ring_buffer_read(&buf->backend, buf->iter.read_offset,
  63                                     dest, buf->iter.payload_len);
  64 }
  65
  66 extern int lib_ring_buffer_iterator_open(struct lib_ring_buffer *buf);
  67 extern void lib_ring_buffer_iterator_release(struct lib_ring_buffer *buf);
  68 extern int channel_iterator_open(struct channel *chan);
  69 extern void channel_iterator_release(struct channel *chan);
  70
  71 extern const struct file_operations channel_payload_file_operations;
  72 extern const struct file_operations lib_ring_buffer_payload_file_operations;
  73
  74 /*
  75  * Used internally.
  76  */
  77 int channel_iterator_init(struct channel *chan);
  78 void channel_iterator_unregister_notifiers(struct channel *chan);
  79 void channel_iterator_free(struct channel *chan);
  80 void channel_iterator_reset(struct channel *chan);
  81 void lib_ring_buffer_iterator_reset(struct lib_ring_buffer *buf);
  82
  83 #endif /* _LIB_RING_BUFFER_ITERATOR_H */