105 lines
3.0 KiB
C
105 lines
3.0 KiB
C
#ifndef UNIVERSAL_SERVICE_H
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#define UNIVERSAL_SERVICE_H
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/* Copyright (C) 2024 Peter McGoron
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program 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
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* GNU 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 Public
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* License along with this program. If not, see
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* <https://www.gnu.org/licenses/>.
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*/
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#include <stddef.h>
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#if !defined(UNS_WORD) && __STDC_VERSION__ >= 199101L
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# include <stdint.h>
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# include <limits.h>
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# define UNS_WORD uintptr_t
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# define UNS_SIGNED_WORD intptr_t
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# define UNS_WORD_MAX UINTPTR_MAX
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# define UNS_SWORD_MAX INTPTR_MAX
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# define UNS_SWORD_MIN INTPTR_MIN
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#elif !defined(UNS_WORD)
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# include <limits.h>
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# define UNS_WORD unsigned long
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# define UNS_WORD_MAX ULONG_MAX
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# define UNS_SIGNED_WORD long
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# define UNS_SWORD_MAX LONG_MAX
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# define UNS_SWORD_MIN LONG_MIN
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#endif
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typedef UNS_WORD uns_word;
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typedef UNS_SIGNED_WORD uns_sword;
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/** Doubly linked list used to
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*
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* 1) Store roots of the GC,
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* 2) Store GC pointers used in C and possibly not pointed-to anywhere
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* else in GC space,
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* 3) Preserve the location of a pointer after it moves.
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*
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* A root that is not a part of any GC MUST have ``prev`` and ``next``
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* set to NULL.
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*/
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struct uns_ctr {
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struct uns_ctr *prev;
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void *p;
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struct uns_ctr *next;
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};
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struct uns_gc {
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void *ctx;
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/* The collector only changes the pointer values of "p".
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*
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* * The collector never adds or removes roots.
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* * The collector never rearranges the order of the container structures.
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*
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* The roots list can have repeated values.
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*/
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struct uns_ctr *roots;
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size_t next_alloc;
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void (*oom)(struct uns_gc *);
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void (*after_gc)(struct uns_gc *);
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size_t before_collection;
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size_t after_collection;
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long collection_number;
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void (*deinit)(struct uns_gc *);
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/* These functions, and only these functions, may invalidate
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* pointers by either moving them or freeing them.
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*/
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int (*collect)(struct uns_gc *);
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void *(*alloc)(struct uns_gc *, size_t);
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void *(*alloc_record)(struct uns_gc *, size_t);
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/* These functions MUST NOT cause collections. */
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/* This function is optional. It is only provided if the GC can
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* calculate the length of the pointer quickly.
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*/
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size_t (*len)(void *);
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void (*record_set_ptr)(void *, size_t, void *);
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void *(*record_get_ptr)(void *, size_t);
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};
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/** Add a root to the GC. The root must point to valid memory, or NULL. */
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void uns_root_add(struct uns_gc *gc, struct uns_ctr *root);
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/** Remove a root from the GC. It is OK to remove a root that is not a
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* part of any GC using this function (the call will have no effect).
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*/
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void uns_root_remove(struct uns_gc *gc, struct uns_ctr *root);
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#endif
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