src/common/dynamic-buffer.h

   1 /*
   2  * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This library is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This library is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  11  * for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18 #ifndef LTTNG_DYNAMIC_BUFFER_H
  19 #define LTTNG_DYNAMIC_BUFFER_H
  20
  21 #include <stddef.h>
  22 #include <stdint.h>
  23
  24 struct lttng_dynamic_buffer {
  25         char *data;
  26         size_t size;
  27         size_t capacity;
  28 };
  29
  30 void lttng_dynamic_buffer_init(struct lttng_dynamic_buffer *buffer);
  31
  32 int lttng_dynamic_buffer_append(struct lttng_dynamic_buffer *buffer,
  33                 const void *buf, size_t len);
  34
  35 /*
  36  * Set the buffer's size to new_size. The capacity of the buffer will
  37  * be expanded (if necessary) to accomodate new_size. Areas acquired by
  38  * an enlarging new_size _will be zeroed_.
  39  *
  40  * Be careful to expand the buffer's size _before_ calling out external
  41  * APIs (e.g. read(3)) which may populate the buffer as setting the size
  42  * _after_ will zero-out the result of the operation.
  43  */
  44 int lttng_dynamic_buffer_set_size(struct lttng_dynamic_buffer *buffer,
  45                 size_t new_size);
  46
  47 /*
  48  * Set the buffer's capacity to accomodate the new_capacity, allocating memory
  49  * as necessary. The buffer's content is preserved.
  50  *
  51  * If the current size > new_capacity, the operation will fail.
  52  */
  53 int lttng_dynamic_buffer_set_capacity(struct lttng_dynamic_buffer *buffer,
  54                 size_t new_capacity);
  55
  56 /* Release any memory used by the dynamic buffer. */
  57 void lttng_dynamic_buffer_reset(struct lttng_dynamic_buffer *buffer);
  58
  59 #endif /* LTTNG_DYNAMIC_BUFFER_H */