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#include <u.h>
#include <libc.h>
#include <draw.h>
#include <cursor.h>
#include <event.h>
#include <bio.h>
#include <plumb.h>
#include <ctype.h>
#include <keyboard.h>
#include <thread.h>
#include "page.h"
typedef struct Cached Cached;
struct Cached
{
Document *doc;
int page;
int angle;
Image *im;
};
static Cached cache[5];
static int rabusy;
static Image*
questionmark(void)
{
static Image *im;
if(im)
return im;
im = xallocimage(display, Rect(0,0,50,50), GREY1, 1, DBlack);
if(im == nil)
return nil;
string(im, ZP, display->white, ZP, display->defaultfont, "?");
return im;
}
void
cacheflush(void)
{
int i;
Cached *c;
for(i=0; i<nelem(cache); i++){
c = &cache[i];
if(c->im)
freeimage(c->im);
c->im = nil;
c->doc = nil;
}
}
static Image*
_cachedpage(Document *doc, int angle, int page, char *ra)
{
int i;
Cached *c, old;
Image *im, *tmp;
if((page < 0 || page >= doc->npage) && !doc->fwdonly)
return nil;
Again:
for(i=0; i<nelem(cache); i++){
c = &cache[i];
if(c->doc == doc && c->angle == angle && c->page == page){
if(chatty) fprint(2, "cache%s hit %d\n", ra, page);
goto Found;
}
if(c->doc == nil)
break;
}
if(i >= nelem(cache))
i = nelem(cache)-1;
c = &cache[i];
if(c->im)
freeimage(c->im);
c->im = nil;
c->doc = nil;
c->page = -1;
if(chatty) fprint(2, "cache%s load %d\n", ra, page);
im = doc->drawpage(doc, page);
if(im == nil){
if(doc->fwdonly) /* end of file */
wexits(0);
im = questionmark();
if(im == nil){
Flush:
if(i > 0){
cacheflush();
goto Again;
}
fprint(2, "out of memory: %r\n");
wexits("memory");
}
return im;
}
if(im->r.min.x != 0 || im->r.min.y != 0){
/* translate to 0,0 */
tmp = xallocimage(display, Rect(0, 0, Dx(im->r), Dy(im->r)), im->chan, 0, DNofill);
if(tmp == nil){
freeimage(im);
goto Flush;
}
drawop(tmp, tmp->r, im, nil, im->r.min, S);
freeimage(im);
im = tmp;
}
switch(angle){
case 90:
im = rot90(im);
break;
case 180:
rot180(im);
break;
case 270:
im = rot270(im);
break;
}
if(im == nil)
goto Flush;
c->doc = doc;
c->page = page;
c->angle = angle;
c->im = im;
Found:
if(chatty) fprint(2, "cache%s mtf %d @%d:", ra, c->page, i);
old = *c;
memmove(cache+1, cache, (c-cache)*sizeof cache[0]);
cache[0] = old;
if(chatty){
for(i=0; i<nelem(cache); i++)
fprint(2, " %d", cache[i].page);
fprint(2, "\n");
}
if(chatty) fprint(2, "cache%s return %d %p\n", ra, old.page, old.im);
return old.im;
}
static void
raproc(void *a)
{
Cached *c;
c = a;
lockdisplay(display);
_cachedpage(c->doc, c->angle, c->page, "-ra");
rabusy = 0;
unlockdisplay(display);
free(c);
threadexits(0);
}
Image*
cachedpage(Document *doc, int angle, int page)
{
static int lastpage = -1;
Cached *c;
Image *im;
int ra;
if(doc->npage < 1)
return display->white;
im = _cachedpage(doc, angle, page, "");
if(im == nil)
return nil;
/* readahead */
ra = -1;
if(!rabusy){
if(page == lastpage+1)
ra = page+1;
else if(page == lastpage-1)
ra = page-1;
}
lastpage = page;
if(ra >= 0){
c = emalloc(sizeof(*c));
c->doc = doc;
c->angle = angle;
c->page = ra;
c->im = nil;
rabusy = 1;
if(proccreate(raproc, c, mainstacksize) == -1)
rabusy = 0;
}
return im;
}
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