implement Diskblocks; ## adapted from Acme's disk.b# include "sys.m";	sys: Sys; include "diskblocks.m"; init(){	sys = load Sys Sys->PATH;} tempfile(): ref Sys->FD{	user := "inferno";	fd := sys->open("/dev/user", Sys->OREAD);	if(fd != nil){		b := array[Sys->NAMEMAX] of byte;		n := sys->read(fd, b, len b);		if(n > 0)			user = string b[0:n];	}	fd = nil;	buf := sys->sprint("/tmp/X%d.%.4sblks", sys->pctl(0, nil), user);	for(i:='A'; i<='Z'; i++){		buf[5] = i;		if(sys->stat(buf).t0 == 0)			continue;		fd = sys->create(buf, Sys->ORDWR|Sys->ORCLOSE|Sys->OEXCL, 8r600);		if(fd != nil)			return fd;	}	return nil;} Disk.init(fd: ref Sys->FD, gran: int, maxblock: int): ref Disk{	d := ref Disk;	if(gran == 0 || maxblock%gran != 0)		return nil;	d.maxblock = maxblock;	d.gran = gran;	d.free = array[maxblock/gran+1] of list of ref Block;	d.addr = big 0;	d.fd = fd;	d.lock = chan[1] of int;	return d;} ntosize(d: ref Disk, n: int): (int, int){	if (n > d.maxblock)		return (-1, -1);	size := n;	if((size % d.gran) != 0)		size += d.gran - size%d.gran;	# last bucket holds blocks of exactly d.maxblock	return (size, size/d.gran);} Disk.new(d: self ref Disk, n: int): ref Block{	(size, i) := ntosize(d, n);	if(i < 0){		sys->werrstr("illegal Disk allocation");		return nil;	}	b: ref Block;	d.lock <-= 1;	if(d.free[i] != nil){		b = hd d.free[i];		d.free[i] = tl d.free[i];	}else{		b = ref Block(d.addr, 0);		d.addr += big size;	}	<-d.lock;	b.n = n;	return b;} Disk.release(d: self ref Disk, b: ref Block){	(nil, i) := ntosize(d, b.n);	d.lock <-= 1;	d.free[i] = b :: d.free[i];	<-d.lock;} Disk.write(d: self ref Disk, b: ref Block, a: array of byte, n: int): ref Block{	if(b != nil){		(size, nil) := ntosize(d, b.n);		(nsize, nil) := ntosize(d, n);		if(size != nsize){			d.release(b);			b = d.new(n);		}	}else		b = d.new(n);	if(b == nil)		return nil;	if(sys->pwrite(d.fd, a, n, b.addr) != n){		sys->werrstr(sys->sprint("Disk write error: %r"));		return nil;	}	b.n = n;	return b;} Disk.read(d: self ref Disk, b: ref Block, a: array of byte, n: int): int{	if(b == nil || n > b.n){		sys->werrstr("read request bigger than block");		return -1;	}	return sys->pread(d.fd, a, n, b.addr);}