glib2.0/glib/gslice.c

326 lines
8.8 KiB
C

/* GLIB sliced memory - fast concurrent memory chunk allocator
* Copyright (C) 2005 Tim Janik
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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 library; if not, see <http://www.gnu.org/licenses/>.
*/
/* MT safe */
#include "config.h"
#include "glibconfig.h"
#include <stdio.h>
#include <string.h>
#include "gslice.h"
#include "gmem.h" /* gslice.h */
#include "glib_trace.h"
#include "gprintf.h"
/* --- auxiliary functions --- */
void
g_slice_set_config (GSliceConfig ckey,
gint64 value)
{
/* deprecated, no implementation */
}
gint64
g_slice_get_config (GSliceConfig ckey)
{
/* deprecated, no implementation */
return 0;
}
gint64*
g_slice_get_config_state (GSliceConfig ckey,
gint64 address,
guint *n_values)
{
/* deprecated, no implementation */
return NULL;
}
/* --- API functions --- */
/**
* g_slice_new:
* @type: the type to allocate, typically a structure name
*
* A convenience macro to allocate a block of memory from the
* slice allocator.
*
* It calls g_slice_alloc() with `sizeof (@type)` and casts the
* returned pointer to a pointer of the given type, avoiding a type
* cast in the source code.
*
* This can never return %NULL as the minimum allocation size from
* `sizeof (@type)` is 1 byte.
*
* Since GLib 2.76 this always uses the system malloc() implementation
* internally.
*
* Returns: (not nullable): a pointer to the allocated block, cast to a pointer
* to @type
*
* Since: 2.10
*/
/**
* g_slice_new0:
* @type: the type to allocate, typically a structure name
*
* A convenience macro to allocate a block of memory from the
* slice allocator and set the memory to 0.
*
* It calls g_slice_alloc0() with `sizeof (@type)`
* and casts the returned pointer to a pointer of the given type,
* avoiding a type cast in the source code.
*
* This can never return %NULL as the minimum allocation size from
* `sizeof (@type)` is 1 byte.
*
* Since GLib 2.76 this always uses the system malloc() implementation
* internally.
*
* Returns: (not nullable): a pointer to the allocated block, cast to a pointer
* to @type
*
* Since: 2.10
*/
/**
* g_slice_dup:
* @type: the type to duplicate, typically a structure name
* @mem: (not nullable): the memory to copy into the allocated block
*
* A convenience macro to duplicate a block of memory using
* the slice allocator.
*
* It calls g_slice_copy() with `sizeof (@type)`
* and casts the returned pointer to a pointer of the given type,
* avoiding a type cast in the source code.
*
* This can never return %NULL.
*
* Since GLib 2.76 this always uses the system malloc() implementation
* internally.
*
* Returns: (not nullable): a pointer to the allocated block, cast to a pointer
* to @type
*
* Since: 2.14
*/
/**
* g_slice_free:
* @type: the type of the block to free, typically a structure name
* @mem: (nullable): a pointer to the block to free
*
* A convenience macro to free a block of memory that has
* been allocated from the slice allocator.
*
* It calls g_slice_free1() using `sizeof (type)`
* as the block size.
* Note that the exact release behaviour can be changed with the
* [`G_DEBUG=gc-friendly`][G_DEBUG] environment variable.
*
* If @mem is %NULL, this macro does nothing.
*
* Since GLib 2.76 this always uses the system free() implementation internally.
*
* Since: 2.10
*/
/**
* g_slice_free_chain:
* @type: the type of the @mem_chain blocks
* @mem_chain: (nullable): a pointer to the first block of the chain
* @next: the field name of the next pointer in @type
*
* Frees a linked list of memory blocks of structure type @type.
*
* The memory blocks must be equal-sized, allocated via
* g_slice_alloc() or g_slice_alloc0() and linked together by
* a @next pointer (similar to #GSList). The name of the
* @next field in @type is passed as third argument.
* Note that the exact release behaviour can be changed with the
* [`G_DEBUG=gc-friendly`][G_DEBUG] environment variable.
*
* If @mem_chain is %NULL, this function does nothing.
*
* Since GLib 2.76 this always uses the system free() implementation internally.
*
* Since: 2.10
*/
/**
* g_slice_alloc:
* @block_size: the number of bytes to allocate
*
* Allocates a block of memory from the libc allocator.
*
* The block address handed out can be expected to be aligned
* to at least `1 * sizeof (void*)`.
*
* Since GLib 2.76 this always uses the system malloc() implementation
* internally.
*
* Returns: (nullable): a pointer to the allocated memory block, which will
* be %NULL if and only if @mem_size is 0
*
* Since: 2.10
*/
gpointer
g_slice_alloc (gsize mem_size)
{
gpointer mem;
mem = g_malloc (mem_size);
TRACE (GLIB_SLICE_ALLOC((void*)mem, mem_size));
return mem;
}
/**
* g_slice_alloc0:
* @block_size: the number of bytes to allocate
*
* Allocates a block of memory via g_slice_alloc() and initializes
* the returned memory to 0.
*
* Since GLib 2.76 this always uses the system malloc() implementation
* internally.
*
* Returns: (nullable): a pointer to the allocated block, which will be %NULL
* if and only if @mem_size is 0
*
* Since: 2.10
*/
gpointer
g_slice_alloc0 (gsize mem_size)
{
gpointer mem = g_slice_alloc (mem_size);
if (mem)
memset (mem, 0, mem_size);
return mem;
}
/**
* g_slice_copy:
* @block_size: the number of bytes to allocate
* @mem_block: the memory to copy
*
* Allocates a block of memory from the slice allocator
* and copies @block_size bytes into it from @mem_block.
*
* @mem_block must be non-%NULL if @block_size is non-zero.
*
* Since GLib 2.76 this always uses the system malloc() implementation
* internally.
*
* Returns: (nullable): a pointer to the allocated memory block,
* which will be %NULL if and only if @mem_size is 0
*
* Since: 2.14
*/
gpointer
g_slice_copy (gsize mem_size,
gconstpointer mem_block)
{
gpointer mem = g_slice_alloc (mem_size);
if (mem)
memcpy (mem, mem_block, mem_size);
return mem;
}
/**
* g_slice_free1:
* @block_size: the size of the block
* @mem_block: (nullable): a pointer to the block to free
*
* Frees a block of memory.
*
* The memory must have been allocated via g_slice_alloc() or
* g_slice_alloc0() and the @block_size has to match the size
* specified upon allocation. Note that the exact release behaviour
* can be changed with the [`G_DEBUG=gc-friendly`][G_DEBUG] environment
* variable.
*
* If @mem_block is %NULL, this function does nothing.
*
* Since GLib 2.76 this always uses the system free_sized() implementation
* internally.
*
* Since: 2.10
*/
void
g_slice_free1 (gsize mem_size,
gpointer mem_block)
{
if (G_UNLIKELY (g_mem_gc_friendly && mem_block))
memset (mem_block, 0, mem_size);
g_free_sized (mem_block, mem_size);
TRACE (GLIB_SLICE_FREE((void*)mem_block, mem_size));
}
/**
* g_slice_free_chain_with_offset:
* @block_size: the size of the blocks
* @mem_chain: (nullable): a pointer to the first block of the chain
* @next_offset: the offset of the @next field in the blocks
*
* Frees a linked list of memory blocks of structure type @type.
*
* The memory blocks must be equal-sized, allocated via
* g_slice_alloc() or g_slice_alloc0() and linked together by a
* @next pointer (similar to #GSList). The offset of the @next
* field in each block is passed as third argument.
* Note that the exact release behaviour can be changed with the
* [`G_DEBUG=gc-friendly`][G_DEBUG] environment variable.
*
* If @mem_chain is %NULL, this function does nothing.
*
* Since GLib 2.76 this always uses the system free_sized() implementation
* internally.
*
* Since: 2.10
*/
void
g_slice_free_chain_with_offset (gsize mem_size,
gpointer mem_chain,
gsize next_offset)
{
gpointer slice = mem_chain;
while (slice)
{
guint8 *current = slice;
slice = *(gpointer *) (current + next_offset);
if (G_UNLIKELY (g_mem_gc_friendly))
memset (current, 0, mem_size);
g_free_sized (current, mem_size);
}
}
#ifdef G_ENABLE_DEBUG
void
g_slice_debug_tree_statistics (void)
{
g_fprintf (stderr, "GSlice: Implementation dropped in GLib 2.76\n");
}
#endif /* G_ENABLE_DEBUG */