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a03950b43c
We have to ensure that the memory location is sufficiently aligned to store any object. This unbreaks the code for CHERI where using gsize results in values that are only aligned to 8 bytes, but we need 16 byte alignment for pointers. This is fully API/ABI compatible since amount of padding before the actual allocation does not change for existing architectures, only for CHERI. Helps: https://gitlab.gnome.org/GNOME/glib/-/issues/2842
70 lines
2.4 KiB
C
70 lines
2.4 KiB
C
/* GObject - GLib Type, Object, Parameter and Signal Library
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* Copyright (C) 2009 Benjamin Otte <otte@gnome.org>
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*
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* SPDX-License-Identifier: LGPL-2.1-or-later
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General
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* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __G_ATOMIC_ARRAY_H__
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#define __G_ATOMIC_ARRAY_H__
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#if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
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#error "Only <glib-object.h> can be included directly."
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#endif
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#include <glib/glib.h>
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G_BEGIN_DECLS
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typedef union _GAtomicArrayMetadata
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{
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gsize size;
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/* We have to ensure that the memory location is sufficiently aligned to
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* store any object. With C11 this would be max_align_t, but in practise
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* gpointer is sufficient for all known architectures. We could change
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* this to `_Alignas(max_align_t) char pad` once we depend on C11. */
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gpointer _alignment_padding;
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} GAtomicArrayMetadata;
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#define G_ATOMIC_ARRAY_DATA_SIZE(mem) (((GAtomicArrayMetadata *) (mem) - 1)->size)
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typedef struct _GAtomicArray GAtomicArray;
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struct _GAtomicArray {
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gpointer data; /* elements - atomic */
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};
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void _g_atomic_array_init (GAtomicArray *array);
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gpointer _g_atomic_array_copy (GAtomicArray *array,
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gsize header_size,
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gsize additional_element_size);
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void _g_atomic_array_update (GAtomicArray *array,
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gpointer new_data);
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#define G_ATOMIC_ARRAY_GET_LOCKED(_array, _type) ((_type *)((_array)->data))
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#define G_ATOMIC_ARRAY_DO_TRANSACTION(_array, _type, _C_) G_STMT_START { \
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gpointer *_datap = &(_array)->data; \
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_type *transaction_data, *__check; \
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\
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__check = g_atomic_pointer_get (_datap); \
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do { \
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transaction_data = __check; \
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{_C_;} \
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__check = g_atomic_pointer_get (_datap); \
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} while (transaction_data != __check); \
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} G_STMT_END
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G_END_DECLS
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#endif /* __G_ATOMIC_ARRAY_H__ */
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