/*  * 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 <draw.h>#include <cursor.h>#include <event.h>#include <bio.h>#include <plumb.h>#include <ctype.h>#include <keyboard.h>#include "page.h" typedef struct Cached Cached;struct Cached{	Document *doc;	int page;	int angle;	Image *im;}; static Cached cache[5]; 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;} voidcacheflush(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;	static int lastpage = -1; 	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;} Image*cachedpage(Document *doc, int angle, int page){	static int lastpage = -1;	static int rabusy;	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){		rabusy = 1;		switch(rfork(RFPROC|RFMEM|RFNOWAIT)){		case -1:			rabusy = 0;			break;		case 0:			lockdisplay(display);			_cachedpage(doc, angle, ra, "-ra");			rabusy = 0;			unlockdisplay(display);			_exits(nil);		default:			break;		}	}	return im;}