#include	<u.h>#include	<libc.h>#include	<bio.h> static	Biobufhdr*	wbufs[20];static	int		atexitflag; staticvoidbatexit(void){	Biobufhdr *bp;	int i; 	for(i=0; i<nelem(wbufs); i++) {		bp = wbufs[i];		if(bp != 0) {			wbufs[i] = 0;			Bflush(bp);		}	}} staticvoiddeinstall(Biobufhdr *bp){	int i; 	for(i=0; i<nelem(wbufs); i++)		if(wbufs[i] == bp)			wbufs[i] = 0;} staticvoidinstall(Biobufhdr *bp){	int i; 	deinstall(bp);	for(i=0; i<nelem(wbufs); i++)		if(wbufs[i] == 0) {			wbufs[i] = bp;			break;		}	if(atexitflag == 0) {		atexitflag = 1;		atexit(batexit);	}} static intbiodummy(Biobufhdr*, void*, long){	return 0;} static intbioread(Biobufhdr *bp, void *v, long n){	return read(bp->fid, v, n);} static intbiowrite(Biobufhdr *bp, void *v, long n){	return write(bp->fid, v, n);} intBinits(Biobufhdr *bp, int f, int mode, uchar *p, int size){	p += Bungetsize;	/* make room for Bungets */	size -= Bungetsize; 	switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {	default:		fprint(2, "Binits: unknown mode %d\n", mode);		return Beof; 	case OREAD:		bp->state = Bractive;		bp->ocount = 0;		bp->iof = bioread;		break; 	case OWRITE:		install(bp);		bp->state = Bwactive;		bp->ocount = -size;		bp->iof = biowrite;		break;	}	bp->bbuf = p;	bp->ebuf = p+size;	bp->bsize = size;	bp->icount = 0;	bp->gbuf = bp->ebuf;	bp->fid = f;	bp->flag = 0;	bp->rdline = 0;	bp->offset = 0;	bp->runesize = 0;	bp->errorf = nil;	return 0;}  intBinit(Biobuf *bp, int f, int mode){	return Binits(bp, f, mode, bp->b, sizeof(bp->b));} Biobuf*Bfdopen(int fd, int mode){	Biobuf *bp; 	bp = malloc(sizeof(Biobuf));	if(bp == nil)		return nil;	if(Binits(bp, fd, mode, bp->b, sizeof(bp->b)) != 0){		free(bp);		return nil;	}	bp->flag = Bmagic;			/* mark bp open & malloced */	setmalloctag(bp, getcallerpc(&fd));	return bp;} Biobuf*Bopen(char *name, int mode){	Biobuf *bp;	int fd; 	switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {	default:		fprint(2, "Bopen: unknown mode %#x\n", mode);		return nil;	case OREAD:		fd = open(name, mode);		break;	case OWRITE:		fd = create(name, mode, 0666);		break;	}	if(fd < 0)		return nil;	bp = Bfdopen(fd, mode);	if(bp == nil){		close(fd);		return nil;	}	setmalloctag(bp, getcallerpc(&name));	return bp;} Bstr*Bstropen(void *p, int size){	Bstr *b; 	b = malloc(sizeof(Bstr) + Bungetsize + size);	if(b == nil)		return nil;	memmove(b->b + Bungetsize, p, size);	Binits(b, -1, OREAD, b->b, size + Bungetsize);	b->iof = biodummy;	b->icount = -size;	b->flag = Bmagic;	setmalloctag(b, getcallerpc(&p));	return b;} intBterm(Biobufhdr *bp){	int r; 	deinstall(bp);	r = Bflush(bp);	if(bp->flag == Bmagic) {		bp->flag = 0;		close(bp->fid);		bp->fid = -1;			/* prevent accidents */		free(bp);	}	/* otherwise opened with Binit(s) */	return r;} voidBiofn(Biobufhdr *bp, int (*f)(Biobufhdr *, void *, long)){	if(f == nil)		if(bp->state == Bwactive)			bp->iof = biowrite;		else			bp->iof = bioread;	else		bp->iof = f;}