implement Diskm; include "common.m"; sys : Sys;acme : Acme;utils : Utils; SZSHORT, Block, Blockincr, Astring : import Dat;error : import utils; init(mods : ref Dat->Mods){	sys = mods.sys;	acme = mods.acme;	utils = mods.utils;} blist : ref Block; tempfile() : ref Sys->FD{	buf := sys->sprint("/tmp/X%d.%.4sacme", sys->pctl(0, nil), utils->getuser());	for(i:='A'; i<='Z'; i++){		buf[5] = i;		(ok, nil) := sys->stat(buf);		if(ok == 0)			continue;		fd := sys->create(buf, Sys->ORDWR|Sys->ORCLOSE, 8r600);		if(fd != nil)			return fd;	}	return nil;} Disk.init() : ref Disk{	d : ref Disk; 	d = ref Disk;	d.free = array[Dat->Maxblock/Dat->Blockincr+1] of ref Block;	d.addr = 0;	d.fd = tempfile();	if(d.fd == nil){		error(sys->sprint("can't create temp file %r"));		acme->acmeexit("temp create");	}	return d;} ntosize(n : int) : (int, int){	size : int; 	if (n > Dat->Maxblock)		error("bad assert in ntosize");	size = n;	if(size & (Blockincr-1))		size += Blockincr - (size & (Blockincr-1));	# last bucket holds blocks of exactly Maxblock	return (size * SZSHORT, size/Blockincr);} Disk.new(d : self ref Disk, n : int) : ref Block{	i, j, size : int;	b, bl : ref Block; 	(size, i) = ntosize(n);	b = d.free[i];	if(b != nil)		d.free[i] = b.next;	else{		# allocate in chunks to reduce malloc overhead		if(blist == nil){			blist = ref Block;			bl = blist;			for(j=0; j<100-1; j++) {				bl.next = ref Block;				bl = bl.next;			}		}		b = blist;		blist = b.next;		b.addr = d.addr;		d.addr += size;	}	b.n = n;	return b;} Disk.release(d : self ref Disk, b : ref Block){	(nil, i) := ntosize(b.n);	b.next = d.free[i];	d.free[i] = b;} Disk.write(d : self ref Disk, bp : ref Block, r : string, n : int) : ref Block{	size, nsize, i : int;	b : ref Block;	ab : array of byte; 	b = bp;	(size, i) = ntosize(b.n);	(nsize, i) = ntosize(n);	if(size != nsize){		d.release(b);		b = d.new(n);	}	if(sys->seek(d.fd, big b.addr, 0) < big 0)		error("seek error in temp file");	ab = utils->stob(r, n);	if(sys->write(d.fd, ab, len ab) != len ab)		error("write error to temp file");	ab = nil;	b.n = n;	return b;} Disk.read(d : self ref Disk, b : ref Block, r : ref Astring, n : int){	ab : array of byte; 	if (n > b.n)		error("bad assert in Disk.read");	(nil, nil) := ntosize(b.n);	if(sys->seek(d.fd, big b.addr, 0) < big 0)		error("seek error in temp file");	ab = array[n*SZSHORT] of byte;	if(sys->read(d.fd, ab, len ab) != len ab)		error("read error from temp file");	utils->btos(ab, r);	ab = nil;}