170 lines
4.5 KiB
C
170 lines
4.5 KiB
C
/*-
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* Copyright (c) 2000 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _SYS_KOBJ_H_
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#define _SYS_KOBJ_H_
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/*
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* Forward declarations
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*/
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typedef struct kobj *kobj_t;
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typedef struct kobj_class *kobj_class_t;
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typedef struct kobj_method kobj_method_t;
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typedef int (*kobjop_t)(void);
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typedef struct kobj_ops *kobj_ops_t;
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typedef struct kobjop_desc *kobjop_desc_t;
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struct malloc_type;
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struct kobj_method {
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kobjop_desc_t desc;
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kobjop_t func;
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};
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/*
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* A class is simply a method table and a sizeof value. When the first
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* instance of the class is created, the method table will be compiled
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* into a form more suited to efficient method dispatch. This compiled
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* method table is always the first field of the object.
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*/
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#define KOBJ_CLASS_FIELDS \
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const char *name; /* class name */ \
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kobj_method_t *methods; /* method table */ \
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size_t size; /* object size */ \
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u_int refs; /* reference count */ \
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kobj_ops_t ops /* compiled method table */
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struct kobj_class {
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KOBJ_CLASS_FIELDS;
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};
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/*
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* Implementation of kobj.
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*/
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#define KOBJ_FIELDS \
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kobj_ops_t ops
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struct kobj {
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KOBJ_FIELDS;
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};
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/*
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* The ops table is used as a cache of results from kobj_lookup_method().
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*/
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#define KOBJ_CACHE_SIZE 256
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struct kobj_ops {
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kobj_method_t cache[KOBJ_CACHE_SIZE];
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kobj_class_t cls;
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};
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struct kobjop_desc {
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unsigned int id; /* unique ID */
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kobjop_t deflt; /* default implementation */
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};
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/*
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* Shorthand for constructing method tables.
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*/
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#define KOBJMETHOD(NAME, FUNC) { &NAME##_desc, (kobjop_t) FUNC }
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#define DEFINE_CLASS(name, methods, size) \
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\
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struct kobj_class name ## _class = { \
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#name, methods, size \
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}
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/*
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* Compile the method table in a class.
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*/
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void kobj_class_compile(kobj_class_t cls);
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/*
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* Compile the method table, with the caller providing the space for
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* the ops table.(for use before malloc is initialised).
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*/
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void kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops);
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/*
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* Free the compiled method table in a class.
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*/
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void kobj_class_free(kobj_class_t cls);
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/*
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* Allocate memory for and initialise a new object.
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*/
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kobj_t kobj_create(kobj_class_t cls,
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struct malloc_type *mtype,
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int mflags);
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/*
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* Initialise a pre-allocated object.
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*/
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void kobj_init(kobj_t obj, kobj_class_t cls);
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/*
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* Delete an object. If mtype is non-zero, free the memory.
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*/
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void kobj_delete(kobj_t obj, struct malloc_type *mtype);
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/*
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* Maintain stats on hits/misses in lookup caches.
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*/
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#ifdef KOBJ_STATS
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extern u_int kobj_lookup_hits;
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extern u_int kobj_lookup_misses;
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#define KOBJOPHIT do { kobj_lookup_hits++; } while (0)
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#define KOBJOPMISS do { kobj_lookup_misses++; } while (0)
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#else
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#define KOBJOPHIT do { } while (0)
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#define KOBJOPMISS do { } while (0)
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#endif
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/*
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* Lookup the method in the cache and if it isn't there look it up the
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* slow way.
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*/
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#define KOBJOPLOOKUP(OPS,OP) do { \
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kobjop_desc_t _desc = &OP##_##desc; \
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kobj_method_t *_ce = \
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&OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \
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if (_ce->desc != _desc) { \
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KOBJOPMISS; \
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kobj_lookup_method(OPS->cls->methods, _ce, _desc); \
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} else { \
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KOBJOPHIT; \
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} \
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_m = _ce->func; \
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} while(0)
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void kobj_lookup_method(kobj_method_t *methods,
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kobj_method_t *ce,
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kobjop_desc_t desc);
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#endif /* !_SYS_KOBJ_H_ */
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