mirror of
https://github.com/9fans/plan9port.git
synced 2025-01-21 11:40:03 +00:00
122 lines
2 KiB
C
122 lines
2 KiB
C
#include "sam.h"
|
|
|
|
static Block *blist;
|
|
|
|
#if 0
|
|
static int
|
|
tempdisk(void)
|
|
{
|
|
char buf[128];
|
|
int i, fd;
|
|
|
|
snprint(buf, sizeof buf, "/tmp/X%d.%.4ssam", getpid(), getuser());
|
|
for(i='A'; i<='Z'; i++){
|
|
buf[5] = i;
|
|
if(access(buf, AEXIST) == 0)
|
|
continue;
|
|
fd = create(buf, ORDWR|ORCLOSE|OCEXEC, 0600);
|
|
if(fd >= 0)
|
|
return fd;
|
|
}
|
|
return -1;
|
|
}
|
|
#else
|
|
extern int tempdisk(void);
|
|
#endif
|
|
|
|
Disk*
|
|
diskinit()
|
|
{
|
|
Disk *d;
|
|
|
|
d = emalloc(sizeof(Disk));
|
|
d->fd = tempdisk();
|
|
if(d->fd < 0){
|
|
fprint(2, "sam: can't create temp file: %r\n");
|
|
exits("diskinit");
|
|
}
|
|
return d;
|
|
}
|
|
|
|
static
|
|
uint
|
|
ntosize(uint n, uint *ip)
|
|
{
|
|
uint size;
|
|
|
|
if(n > Maxblock)
|
|
panic("internal error: ntosize");
|
|
size = n;
|
|
if(size & (Blockincr-1))
|
|
size += Blockincr - (size & (Blockincr-1));
|
|
/* last bucket holds blocks of exactly Maxblock */
|
|
if(ip)
|
|
*ip = size/Blockincr;
|
|
return size * sizeof(Rune);
|
|
}
|
|
|
|
Block*
|
|
disknewblock(Disk *d, uint n)
|
|
{
|
|
uint i, j, size;
|
|
Block *b;
|
|
|
|
size = ntosize(n, &i);
|
|
b = d->free[i];
|
|
if(b)
|
|
d->free[i] = b->u.next;
|
|
else{
|
|
/* allocate in chunks to reduce malloc overhead */
|
|
if(blist == nil){
|
|
blist = emalloc(100*sizeof(Block));
|
|
for(j=0; j<100-1; j++)
|
|
blist[j].u.next = &blist[j+1];
|
|
}
|
|
b = blist;
|
|
blist = b->u.next;
|
|
b->addr = d->addr;
|
|
d->addr += size;
|
|
}
|
|
b->u.n = n;
|
|
return b;
|
|
}
|
|
|
|
void
|
|
diskrelease(Disk *d, Block *b)
|
|
{
|
|
uint i;
|
|
|
|
ntosize(b->u.n, &i);
|
|
b->u.next = d->free[i];
|
|
d->free[i] = b;
|
|
}
|
|
|
|
void
|
|
diskwrite(Disk *d, Block **bp, Rune *r, uint n)
|
|
{
|
|
int size, nsize;
|
|
Block *b;
|
|
|
|
b = *bp;
|
|
size = ntosize(b->u.n, nil);
|
|
nsize = ntosize(n, nil);
|
|
if(size != nsize){
|
|
diskrelease(d, b);
|
|
b = disknewblock(d, n);
|
|
*bp = b;
|
|
}
|
|
if(pwrite(d->fd, r, n*sizeof(Rune), b->addr) != n*sizeof(Rune))
|
|
panic("write error to temp file");
|
|
b->u.n = n;
|
|
}
|
|
|
|
void
|
|
diskread(Disk *d, Block *b, Rune *r, uint n)
|
|
{
|
|
if(n > b->u.n)
|
|
panic("internal error: diskread");
|
|
|
|
ntosize(b->u.n, nil); /* called only for sanity check on Maxblock */
|
|
if(pread(d->fd, r, n*sizeof(Rune), b->addr) != n*sizeof(Rune))
|
|
panic("read error from temp file");
|
|
}
|