Make lttng_dynamic_buffer_append_buffer const-correct

[lttng-tools.git] / src / common / dynamic-buffer.c

diff --git a/src/common/dynamic-buffer.c b/src/common/dynamic-buffer.c
index 7184a3400888ce602c9ec59377ee9c426fc3a5ee..7005ef501776c0801f951e00b3a01aa17c699c85 100644 (file)
--- a/src/common/dynamic-buffer.c
+++ b/src/common/dynamic-buffer.c
@@ -1,25 +1,18 @@
 /*
- * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License, version 2.1 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
- * for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <common/dynamic-buffer.h>
-#include <common/macros.h>
 #include <common/utils.h>
 #include <assert.h>
 
+/*
+ * Round to (upper) power of two, val is returned if it already is a power of
+ * two.
+ */
 static
 size_t round_to_power_of_2(size_t val)
 {
@@ -34,12 +27,14 @@ size_t round_to_power_of_2(size_t val)
        return rounded;
 }
 
+LTTNG_HIDDEN
 void lttng_dynamic_buffer_init(struct lttng_dynamic_buffer *buffer)
 {
        assert(buffer);
        memset(buffer, 0, sizeof(*buffer));
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_append(struct lttng_dynamic_buffer *buffer,
                const void *buf, size_t len)
 {
@@ -55,11 +50,11 @@ int lttng_dynamic_buffer_append(struct lttng_dynamic_buffer *buffer,
                goto end;
        }
 
-       assert(buffer->capacity >= buffer->size);
-       if (buffer->capacity < (len + buffer->size)) {
+       assert(buffer->_capacity >= buffer->size);
+       if (buffer->_capacity < (len + buffer->size)) {
                ret = lttng_dynamic_buffer_set_capacity(buffer,
-                               buffer->capacity +
-                               (len - (buffer->capacity - buffer->size)));
+                               buffer->_capacity +
+                               (len - (buffer->_capacity - buffer->size)));
                if (ret) {
                        goto end;
                }
@@ -71,8 +66,9 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_append_buffer(struct lttng_dynamic_buffer *dst_buffer,
-               struct lttng_dynamic_buffer *src_buffer)
+               const struct lttng_dynamic_buffer *src_buffer)
 {
        int ret;
 
@@ -87,6 +83,7 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_set_size(struct lttng_dynamic_buffer *buffer,
                size_t new_size)
 {
@@ -100,11 +97,13 @@ int lttng_dynamic_buffer_set_size(struct lttng_dynamic_buffer *buffer,
                goto end;
        }
 
-       if (new_size > buffer->capacity) {
+       if (new_size > buffer->_capacity) {
                ret = lttng_dynamic_buffer_set_capacity(buffer, new_size);
                if (ret) {
                        goto end;
                }
+
+               memset(buffer->data + buffer->size, 0, new_size - buffer->size);
        } else if (new_size > buffer->size) {
                memset(buffer->data + buffer->size, 0, new_size - buffer->size);
        } else {
@@ -123,60 +122,58 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_set_capacity(struct lttng_dynamic_buffer *buffer,
-               size_t new_capacity)
+               size_t demanded_capacity)
 {
        int ret = 0;
-       size_t rounded_capacity = round_to_power_of_2(new_capacity);
+       void *new_buf;
+       size_t new_capacity = demanded_capacity ?
+                       round_to_power_of_2(demanded_capacity) : 0;
 
-       if (!buffer || new_capacity < buffer->size) {
+       if (!buffer || demanded_capacity < buffer->size) {
+               /*
+                * Shrinking a buffer's size by changing its capacity is
+                * unsupported.
+                */
                ret = -1;
                goto end;
        }
 
-       if (rounded_capacity == buffer->capacity) {
+       if (new_capacity == buffer->_capacity) {
                goto end;
        }
 
-       if (!buffer->data) {
-               buffer->data = zmalloc(rounded_capacity);
-               if (!buffer->data) {
-                       ret = -1;
-                       goto end;
-               }
-       } else {
-               void *new_buf;
-
-               new_buf = realloc(buffer->data, rounded_capacity);
-               if (new_buf) {
-                       if (rounded_capacity > buffer->capacity) {
-                               memset(new_buf + buffer->capacity, 0,
-                                               rounded_capacity - buffer->capacity);
-                       }
-               } else {
-                       /* Realloc failed, try to acquire a new block. */
-                       new_buf = zmalloc(rounded_capacity);
-                       if (!new_buf) {
-                               ret = -1;
-                               goto end;
-                       }
-                       memcpy(new_buf, buffer->data, buffer->size);
-                       free(buffer->data);
-               }
-               buffer->data = new_buf;
+       /* Memory is initialized by the size increases. */
+       new_buf = realloc(buffer->data, new_capacity);
+       if (!new_buf) {
+               ret = -1;
+               goto end;
        }
-       buffer->capacity = rounded_capacity;
+       buffer->data = new_buf;
+       buffer->_capacity = new_capacity;
 end:
        return ret;
 }
 
 /* Release any memory used by the dynamic buffer. */
+LTTNG_HIDDEN
 void lttng_dynamic_buffer_reset(struct lttng_dynamic_buffer *buffer)
 {
        if (!buffer) {
                return;
        }
        buffer->size = 0;
-       buffer->capacity = 0;
+       buffer->_capacity = 0;
        free(buffer->data);
 }
+
+LTTNG_HIDDEN
+size_t lttng_dynamic_buffer_get_capacity_left(
+               struct lttng_dynamic_buffer *buffer)
+{
+       if (!buffer) {
+               return 0;
+       }
+       return buffer->_capacity - buffer->size;
+}