76 lines
1,013 B
C
76 lines
1,013 B
C
/*
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* lru lists are circular with a list head
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* pointing to the start and end of the list
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*/
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#include <u.h>
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#include "lru.h"
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/*
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* Create an lru chain of buffers
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*/
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void
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lruinit(Lru *h)
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{
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h->lprev = h->lnext = h;
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}
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/*
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* Add a member to an lru chain
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*/
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void
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lruadd(Lru *h, Lru *m)
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{
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h->lprev->lnext = m;
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m->lprev = h->lprev;
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h->lprev = m;
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m->lnext = h;
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}
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/*
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* Move to end of lru list
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*/
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void
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lruref(Lru *h, Lru *m)
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{
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if(h->lprev == m)
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return; /* alread at end of list */
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/*
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* remove from list
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*/
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m->lprev->lnext = m->lnext;
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m->lnext->lprev = m->lprev;
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/*
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* add in at end
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*/
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h->lprev->lnext = m;
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m->lprev = h->lprev;
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h->lprev = m;
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m->lnext = h;
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}
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/*
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* Move to head of lru list
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*/
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void
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lruderef(Lru *h, Lru *m)
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{
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if(h->lnext == m)
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return; /* alread at head of list */
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/*
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* remove from list
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*/
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m->lprev->lnext = m->lnext;
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m->lnext->lprev = m->lprev;
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/*
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* add in at head
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*/
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h->lnext->lprev = m;
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m->lnext = h->lnext;
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h->lnext = m;
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m->lprev = h;
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}
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