X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fdynamic-buffer.c;h=7005ef501776c0801f951e00b3a01aa17c699c85;hp=c295a5d2eb378f58b557fdfa6c841de6667db810;hb=38b6c4f5eb49d404ff3f2248b017cea415c49618;hpb=1c6def05e37f4a8a828a94aa0ca0e6236877f26f

diff --git a/src/common/dynamic-buffer.c b/src/common/dynamic-buffer.c
index c295a5d2e..7005ef501 100644
--- 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)
 {
@@ -100,23 +97,13 @@ int lttng_dynamic_buffer_set_size(struct lttng_dynamic_buffer *buffer,
 		goto end;
 	}
 
-	if (new_size > buffer->capacity) {
-		size_t original_size = buffer->size;
-		size_t original_capacity = buffer->capacity;
-
+	if (new_size > buffer->_capacity) {
 		ret = lttng_dynamic_buffer_set_capacity(buffer, new_size);
 		if (ret) {
 			goto end;
 		}
 
-		/*
-		 * Zero-initialize the space that was left in the buffer at the
-		 * before we increased its capacity (original capacity - original size).
-		 * The newly acquired capacity (new capacity - original capacity)
-		 * is zeroed by lttng_dynamic_buffer_set_capacity().
-		 */
-		memset(buffer->data + original_size, 0,
-				original_capacity - original_size);
+		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 {
@@ -135,60 +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;
+}