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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;
}
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