/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <auth.h>#include <fcall.h>#include <thread.h>#include <9p.h> enum {	NHASH = 128}; typedef struct Intlist	Intlist;struct Intlist{	ulong	id;	void*	aux;	Intlist*	link;}; struct Intmap{	RWLock;	Intlist*	hash[NHASH];	void (*inc)(void*);}; static ulonghashid(ulong id){	return id%NHASH;} static voidnop(void*){} Intmap*allocmap(void (*inc)(void*)){	Intmap *m; 	m = emalloc9p(sizeof(*m));	if(inc == nil)		inc = nop;	m->inc = inc;	return m;} voidfreemap(Intmap *map, void (*destroy)(void*)){	int i;	Intlist *p, *nlink; 	if(destroy == nil)		destroy = nop;	for(i=0; i<NHASH; i++){		for(p=map->hash[i]; p; p=nlink){			nlink = p->link;			destroy(p->aux);			free(p);		}	}				free(map);} static Intlist**llookup(Intmap *map, ulong id){	Intlist **lf; 	for(lf=&map->hash[hashid(id)]; *lf; lf=&(*lf)->link)		if((*lf)->id == id)			break;	return lf;	} /* * The RWlock is used as expected except that we allow * inc() to be called while holding it.  This is because we're * locking changes to the tree structure, not to the references. * Inc() is expected to have its own locking. */void*lookupkey(Intmap *map, ulong id){	Intlist *f;	void *v; 	rlock(map);	if(f = *llookup(map, id)){		v = f->aux;		map->inc(v);	}else		v = nil;	runlock(map);	return v;} void*insertkey(Intmap *map, ulong id, void *v){	Intlist *f;	void *ov;	ulong h; 	wlock(map);	if(f = *llookup(map, id)){		/* no decrement for ov because we're returning it */		ov = f->aux;		f->aux = v;	}else{		f = emalloc9p(sizeof(*f));		f->id = id;		f->aux = v;		h = hashid(id);		f->link = map->hash[h];		map->hash[h] = f;		ov = nil;	}	wunlock(map);	return ov;	} intcaninsertkey(Intmap *map, ulong id, void *v){	Intlist *f;	int rv;	ulong h; 	wlock(map);	if(*llookup(map, id))		rv = 0;	else{		f = emalloc9p(sizeof *f);		f->id = id;		f->aux = v;		h = hashid(id);		f->link = map->hash[h];		map->hash[h] = f;		rv = 1;	}	wunlock(map);	return rv;	} void*deletekey(Intmap *map, ulong id){	Intlist **lf, *f;	void *ov; 	wlock(map);	if(f = *(lf = llookup(map, id))){		ov = f->aux;		*lf = f->link;		free(f);	}else		ov = nil;	wunlock(map);	return ov;}