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#include <stdlib.h>
#include <string.h>
#include "misc.h"
#include "dllist.h"
#include "cache.h"
#include "help.h"
static inline int hash(int pgno)
{
// very simple...
return pgno % HASH_SIZE;
}
static void do_erc(struct vt_page *ovtp, struct vt_page *nvtp)
{
int l, c;
if (nvtp->errors == 0 && ovtp->lines == nvtp->lines)
return;
for (l = 0; l < H; ++l)
{
if (~nvtp->lines & (1 << l))
memcpy(nvtp->data[l], ovtp->data[l], W);
else if (ovtp->lines & (1 << l))
for (c = 0; c < W; ++c)
if (nvtp->data[l][c] == BAD_CHAR)
nvtp->data[l][c] = ovtp->data[l][c];
}
nvtp->lines |= ovtp->lines;
}
static void cache_close(struct cache *ca)
{
struct cache_page *cp;
int i;
for (i = 0; i < HASH_SIZE; ++i)
while (not dl_empty(ca->hash + i))
{
cp = PTR ca->hash[i].first;
dl_remove(cp->node);
free(cp);
}
free(ca);
}
static void cache_reset(struct cache *ca)
{
struct cache_page *cp, *cpn;
int i;
for (i = 0; i < HASH_SIZE; ++i)
for (cp = PTR ca->hash[i].first; cpn = PTR cp->node->next; cp = cpn)
if (cp->page->pgno / 256 != 9) // don't remove help pages
{
dl_remove(cp->node);
free(cp);
ca->npages--;
}
memset(ca->hi_subno, 0, sizeof(ca->hi_subno[0]) * 0x900);
}
/* Get a page from the cache.
If subno is SUB_ANY, the newest subpage of that page is returned */
static struct vt_page * cache_get(struct cache *ca, int pgno, int subno)
{
struct cache_page *cp;
int h = hash(pgno);
for (cp = PTR ca->hash[h].first; cp->node->next; cp = PTR cp->node->next)
if (cp->page->pgno == pgno)
if (subno == ANY_SUB || cp->page->subno == subno)
{
// found, move to front (make it 'new')
dl_insert_first(ca->hash + h, dl_remove(cp->node));
return cp->page;
}
return 0;
}
/* Put a page in the cache.
If it's already there, it is updated. */
static struct vt_page * cache_put(struct cache *ca, struct vt_page *vtp)
{
struct cache_page *cp;
int h = hash(vtp->pgno);
for (cp = PTR ca->hash[h].first; cp->node->next; cp = PTR cp->node->next)
if (cp->page->pgno == vtp->pgno && cp->page->subno == vtp->subno)
break;
if (cp->node->next)
{
// move to front.
dl_insert_first(ca->hash + h, dl_remove(cp->node));
if (ca->erc)
do_erc(cp->page, vtp);
}
else
{
cp = malloc(sizeof(*cp));
if (cp == 0)
return 0;
if (vtp->subno >= ca->hi_subno[vtp->pgno])
ca->hi_subno[vtp->pgno] = vtp->subno + 1;
ca->npages++;
dl_insert_first(ca->hash + h, cp->node);
}
*cp->page = *vtp;
return cp->page;
}
/* Same as cache_get but doesn't make the found entry new */
static struct vt_page * cache_lookup(struct cache *ca, int pgno, int subno)
{
struct cache_page *cp;
int h = hash(pgno);
for (cp = PTR ca->hash[h].first; cp->node->next; cp = PTR cp->node->next)
if (cp->page->pgno == pgno)
if (subno == ANY_SUB || cp->page->subno == subno)
return cp->page;
return 0;
}
static struct vt_page * cache_foreach_pg(struct cache *ca, int pgno, int subno,
int dir, int (*func)(), void *data)
{
struct vt_page *vtp, *s_vtp = 0;
if (ca->npages == 0)
return 0;
if (vtp = cache_lookup(ca, pgno, subno))
subno = vtp->subno;
else if (subno == ANY_SUB)
subno = dir < 0 ? 0 : 0xffff;
for (;;)
{
subno += dir;
while (subno < 0 || subno >= ca->hi_subno[pgno])
{
pgno += dir;
if (pgno < 0x100)
pgno = 0x9ff;
if (pgno > 0x9ff)
pgno = 0x100;
subno = dir < 0 ? ca->hi_subno[pgno] - 1 : 0;
}
if (vtp = cache_lookup(ca, pgno, subno))
{
if (s_vtp == vtp)
return 0;
if (s_vtp == 0)
s_vtp = vtp;
if (func(data, vtp))
return vtp;
}
}
}
static int cache_mode(struct cache *ca, int mode, int arg)
{
int res = -1;
switch (mode)
{
case CACHE_MODE_ERC:
res = ca->erc;
ca->erc = arg ? 1 : 0;
break;
}
return res;
}
static struct cache_ops cops =
{
cache_close,
cache_get,
cache_put,
cache_reset,
cache_foreach_pg,
cache_mode,
};
struct cache * cache_open(void)
{
struct cache *ca;
struct vt_page *vtp;
int i;
if (not(ca = malloc(sizeof(*ca))))
goto fail1;
for (i = 0; i < HASH_SIZE; ++i)
dl_init(ca->hash + i);
memset(ca->hi_subno, 0, sizeof(ca->hi_subno));
ca->erc = 1;
ca->npages = 0;
ca->op = &cops;
for (vtp = help_pages; vtp < help_pages + nr_help_pages; vtp++)
cache_put(ca, vtp);
return ca;
fail2:
free(ca);
fail1:
return 0;
}
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