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