src/hd/holofile.c

/* Copyright (c) 1999 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ SGI";
#endif

/*
 * Routines for managing holodeck files
 *
 *      9/30/97 GWLarson
 */

#include "holo.h"

#ifndef CACHESIZE
#ifdef BIGMEM
#define CACHESIZE       17      /* default cache size (Mbytes, 0==inf) */
#else
#define CACHESIZE       5
#endif
#endif
#ifndef FREEBEAMS
#define FREEBEAMS       1500    /* maximum beams to free at a time */
#endif
#ifndef PCTFREE
#define PCTFREE         15      /* maximum fraction to free (%) */
#endif
#ifndef MAXFRAGB
#define MAXFRAGB        16      /* fragment blocks/file to track (0==inf) */
#endif
#ifndef FF_DEFAULT
                                /* when to free a beam fragment */
#define FF_DEFAULT      (FF_WRITE|FF_KILL)
#endif
#ifndef MINDIRSEL
                                /* minimum directory seek length */
#define MINDIRSEL       (4*BUFSIZ/sizeof(BEAMI))
#endif

#ifndef BSD
#define write   writebuf        /* safe i/o routines */
#define read    readbuf
#endif

#define FRAGBLK         512     /* number of fragments to allocate at a time */

int     hdfragflags = FF_DEFAULT;       /* tells when to free fragments */
unsigned        hdcachesize = CACHESIZE*1024*1024;      /* target cache size */
unsigned long   hdclock;                /* clock value */

HOLO    *hdlist[HDMAX+1];       /* holodeck pointers (NULL term.) */

static struct fraglist {
        short   nlinks;         /* number of holodeck sections using us */
        short   writable;       /* 0 read-only, <0 write error encountered */
        int     nfrags;         /* number of known fragments */
        BEAMI   *fi;            /* fragments, descending file position */
        long    flen;           /* last known file length */
} *hdfragl;             /* fragment lists, indexed by file descriptor */

static int      nhdfragls;      /* size of hdfragl array */


HOLO *
hdalloc(hproto)         /* allocate and set holodeck section based on grid */
HDGRID  *hproto;
{
        HOLO    hdhead;
        register HOLO   *hp;
        int     n;
                                /* copy grid to temporary header */
        bcopy((char *)hproto, (char *)&hdhead, sizeof(HDGRID));
                                /* compute grid vectors and sizes */
        hdcompgrid(&hdhead);
                                /* allocate header with directory */
        n = sizeof(HOLO)+nbeams(&hdhead)*sizeof(BEAMI);
        if ((hp = (HOLO *)malloc(n)) == NULL)
                return(NULL);
                                /* copy header information */
        copystruct(hp, &hdhead);
                                /* allocate and clear beam list */
        hp->bl = (BEAM **)malloc((nbeams(hp)+1)*sizeof(BEAM *)+sizeof(BEAM));
        if (hp->bl == NULL) {
                free((char *)hp);
                return(NULL);
        }
        bzero((char *)hp->bl, (nbeams(hp)+1)*sizeof(BEAM *)+sizeof(BEAM));
        hp->bl[0] = (BEAM *)(hp->bl+nbeams(hp)+1);      /* set blglob(hp) */
        hp->fd = -1;
        hp->dirty = 0;
        hp->priv = NULL;
                                /* clear beam directory */
        bzero((char *)hp->bi, (nbeams(hp)+1)*sizeof(BEAMI));
        return(hp);             /* all is well */
}


char *
hdrealloc(ptr, siz, rout)       /* (re)allocate memory, retry then error */
char    *ptr;
unsigned        siz;
char    *rout;
{
        register char   *newp;
                                        /* call malloc/realloc */
        if (ptr == NULL) newp = (char *)malloc(siz);
        else newp = (char *)realloc(ptr, siz);
                                        /* check success */
        if (newp == NULL && rout != NULL) {
                hdfreecache(25, NULL);  /* free some memory */
                errno = 0;              /* retry */
                newp = hdrealloc(ptr, siz, NULL);
                if (newp == NULL) {     /* give up and report error */
                        sprintf(errmsg, "out of memory in %s", rout);
                        error(SYSTEM, errmsg);
                }
        }
        return(newp);
}


hdattach(fd, wr)        /* start tracking file fragments for some section */
register int    fd;
int     wr;
{
        if (fd >= nhdfragls) {
                hdfragl = (struct fraglist *)hdrealloc((char *)hdfragl,
                                (fd+1)*sizeof(struct fraglist), "hdattach");
                bzero((char *)(hdfragl+nhdfragls),
                                (fd+1-nhdfragls)*sizeof(struct fraglist));
                nhdfragls = fd+1;
        }
        hdfragl[fd].nlinks++;
        hdfragl[fd].writable = wr;              /* set writable flag */
        hdfragl[fd].flen = lseek(fd, 0L, 2);    /* get file length */
}


/* Do we need a routine to locate file fragments given known occupants? */


hdrelease(fd)           /* stop tracking file fragments for some section */
register int    fd;
{
        if (fd < 0 | fd >= nhdfragls || !hdfragl[fd].nlinks)
                return;
        if (!--hdfragl[fd].nlinks && hdfragl[fd].nfrags) {
                free((char *)hdfragl[fd].fi);
                hdfragl[fd].fi = NULL;
                hdfragl[fd].nfrags = 0;
        }
}


HOLO *
hdinit(fd, hproto)      /* initialize a holodeck section in a file */
int     fd;                     /* corresponding file descriptor */
HDGRID  *hproto;                /* holodeck section grid */
{
        long    rtrunc;
        long    fpos;
        int     writable;
        register HOLO   *hp;
        register int    n;
                                        /* prepare for system errors */
        errno = 0;
        if ((fpos = lseek(fd, 0L, 1)) < 0)
                error(SYSTEM, "cannot determine holodeck file position");
        if (hproto == NULL) {           /* assume we're loading it */
                HDGRID  hpr;
                                                /* load header */
                if (read(fd, (char *)&hpr, sizeof(HDGRID)) != sizeof(HDGRID))
                        error(SYSTEM, "cannot load holodeck header");
                                                /* allocate grid */
                if ((hp = hdalloc(&hpr)) == NULL)
                        goto memerr;
                                                /* load beam directory */
                n = nbeams(hp)*sizeof(BEAMI);
                if (read(fd, (char *)(hp->bi+1), n) != n)
                        error(SYSTEM, "failure loading holodeck directory");
                                                /* check that it's clean */
                for (n = nbeams(hp); n > 0; n--)
                        if (hp->bi[n].fo < 0) {
                                hp->bi[n].fo = 0;
                                error(WARNING, "dirty holodeck section");
                                break;
                        }
                                                /* check writability */
                if (fd < nhdfragls && hdfragl[fd].nlinks)
                        writable = hdfragl[fd].writable;
                else
                        writable = lseek(fd, fpos, 0) == fpos &&
                                write(fd, (char *)hp, sizeof(HDGRID)) ==
                                                        sizeof(HDGRID);
        } else {                        /* else assume we're creating it */
                if ((hp = hdalloc(hproto)) == NULL)
                        goto memerr;
                                                /* write header and skeleton */
                n = nbeams(hp)*sizeof(BEAMI);
                if (write(fd, (char *)hproto, sizeof(HDGRID)) !=
                                        sizeof(HDGRID) ||
                                write(fd, (char *)(hp->bi+1), n) != n)
                        error(SYSTEM, "cannot write header to holodeck file");
                writable = 1;
        }
        hp->fd = fd;    
        hp->dirty = 0;
        biglob(hp)->fo = fpos + sizeof(HDGRID);
                                        /* start tracking fragments */
        hdattach(fd, writable);
                                        /* check rays on disk */
        fpos = hdfilen(fd);
        biglob(hp)->nrd = rtrunc = 0;
        for (n = hproto == NULL ? nbeams(hp) : 0; n > 0; n--)
                if (hp->bi[n].nrd)
                        if (hp->bi[n].fo+hp->bi[n].nrd*sizeof(RAYVAL) > fpos) {
                                rtrunc += hp->bi[n].nrd;
                                hp->bi[n].nrd = 0;
                        } else
                                biglob(hp)->nrd += hp->bi[n].nrd;
        if (rtrunc) {
                sprintf(errmsg, "truncated section, %ld rays lost (%.1f%%)",
                                rtrunc, 100.*rtrunc/(rtrunc+biglob(hp)->nrd));
                error(WARNING, errmsg);
        }
                                        /* add to holodeck list */
        for (n = 0; n < HDMAX; n++)
                if (hdlist[n] == NULL) {
                        hdlist[n] = hp;
                        break;
                }
                                        /* all done */
        return(hp);
memerr:
        error(SYSTEM, "cannot allocate holodeck grid");
}


hdmarkdirty(hp, i)              /* mark holodeck directory position dirty */
register HOLO   *hp;
int     i;
{
        static BEAMI    smudge = {0, -1};
        int     mindist, minpos;
        register int    j;

        if (!hp->dirty++) {                     /* write smudge first time */
                if (lseek(hp->fd, biglob(hp)->fo+(i-1)*sizeof(BEAMI), 0) < 0
                                || write(hp->fd, (char *)&smudge,
                                        sizeof(BEAMI)) != sizeof(BEAMI))
                        error(SYSTEM, "seek/write error in hdmarkdirty");
                hp->dirseg[0].s = i;
                hp->dirseg[0].n = 1;
                return;
        }
                                                /* insert into segment list */
        for (j = hp->dirty; j--; ) {
                if (!j || hp->dirseg[j-1].s < i) {
                        hp->dirseg[j].s = i;
                        hp->dirseg[j].n = 1;
                        break;
                }
                copystruct(hp->dirseg+j, hp->dirseg+(j-1));
        }
        do {                            /* check neighbors */
                mindist = nbeams(hp);           /* find closest */
                for (j = hp->dirty; --j; )
                        if (hp->dirseg[j].s -
                                        (hp->dirseg[j-1].s + hp->dirseg[j-1].n)
                                        < mindist) {
                                minpos = j;
                                mindist = hp->dirseg[j].s -
                                        (hp->dirseg[j-1].s + hp->dirseg[j-1].n);
                        }
                                                /* good enough? */
                if (hp->dirty <= MAXDIRSE && mindist > MINDIRSEL)
                        break;
                j = minpos - 1;                 /* coalesce neighbors */
                if (hp->dirseg[j].s + hp->dirseg[j].n <
                                hp->dirseg[minpos].s + hp->dirseg[minpos].n)
                        hp->dirseg[j].n = hp->dirseg[minpos].s +
                                        hp->dirseg[minpos].n - hp->dirseg[j].s;
                hp->dirty--;
                while (++j < hp->dirty)         /* close the gap */
                        copystruct(hp->dirseg+j, hp->dirseg+(j+1));
        } while (mindist <= MINDIRSEL);
}


int
hdsync(hp, all)                 /* update beams and directory on disk */
register HOLO   *hp;
int     all;
{
        register int    j, n;

        if (hp == NULL) {               /* do all holodecks */
                n = 0;
                for (j = 0; hdlist[j] != NULL; j++)
                        n += hdsync(hdlist[j], all);
                return(n);
        }
                                        /* sync the beams */
        for (j = (all ? nbeams(hp) : 0); j > 0; j--)
                if (hp->bl[j] != NULL)
                        hdsyncbeam(hp, j);
        if (!hp->dirty)                 /* directory clean? */
                return(0);
        errno = 0;                      /* write dirty segments */
        for (j = 0; j < hp->dirty; j++) {
                if (lseek(hp->fd, biglob(hp)->fo +
                                (hp->dirseg[j].s-1)*sizeof(BEAMI), 0) < 0)
                        error(SYSTEM, "cannot seek on holodeck file");
                n = hp->dirseg[j].n * sizeof(BEAMI);
                if (write(hp->fd, (char *)(hp->bi+hp->dirseg[j].s), n) != n)
                        error(SYSTEM, "cannot update section directory");
        }
        hp->dirty = 0;                  /* all clean */
        return(1);
}


unsigned
hdmemuse(all)           /* return memory usage (in bytes) */
int     all;                    /* include overhead (painful) */
{
        long    total = 0;
        register int    i, j;

        for (j = 0; hdlist[j] != NULL; j++) {
                total += blglob(hdlist[j])->nrm * sizeof(RAYVAL);
                if (all) {
                        total += sizeof(HOLO) + sizeof(BEAM *) +
                                        nbeams(hdlist[j]) *
                                                (sizeof(BEAM *)+sizeof(BEAMI));
                        for (i = nbeams(hdlist[j]); i > 0; i--)
                                if (hdlist[j]->bl[i] != NULL)
                                        total += sizeof(BEAM);
                }
        }
        if (all)
                for (j = 0; j < nhdfragls; j++) {
                        total += sizeof(struct fraglist);
                        if (hdfragl[j].nfrags)
                                total += FRAGBLK*sizeof(BEAMI) *
                                        ((hdfragl[j].nfrags-1)/FRAGBLK + 1) ;
                }
        return(total);
}


long
hdfilen(fd)             /* return file length for fd */
int     fd;
{
        long    fpos, flen;

        if (fd < 0)
                return(-1);
        if (fd >= nhdfragls || !hdfragl[fd].nlinks) {
                if ((fpos = lseek(fd, 0L, 1)) < 0)
                        return(-1);
                flen = lseek(fd, 0L, 2);
                lseek(fd, fpos, 0);
                return(flen);
        }
        return(hdfragl[fd].flen);
}


long
hdfiluse(fd, all)       /* compute file usage (in bytes) */
int     fd;                     /* open file descriptor to check */
int     all;                    /* include overhead and unflushed data */
{
        long    total = 0;
        register int    i, j;

        for (j = 0; hdlist[j] != NULL; j++) {
                if (hdlist[j]->fd != fd)
                        continue;
                total += biglob(hdlist[j])->nrd * sizeof(RAYVAL);
                if (all) {
                        for (i = nbeams(hdlist[j]); i > 0; i--)
                                if (hdlist[j]->bl[i] != NULL)
                                        total += sizeof(RAYVAL) *
                                                (hdlist[j]->bl[i]->nrm -
                                                hdlist[j]->bi[i].nrd);
                        total += sizeof(HDGRID) +
                                        nbeams(hdlist[j])*sizeof(BEAMI);
                }
        }
        return(total);          /* does not include fragments */
}


RAYVAL *
hdnewrays(hp, i, nr)    /* allocate space for add'l rays and return pointer */
register HOLO   *hp;
register int    i;
int     nr;                     /* number of new rays desired */
{
        RAYVAL  *p;
        int     n;

        if (nr <= 0) return(NULL);
        CHECK(i < 1 | i > nbeams(hp),
                        CONSISTENCY, "bad beam index given to hdnewrays");
        if (hp->bl[i] != NULL)
                hp->bl[i]->tick = hdclock;      /* preempt swap */
        if (hdcachesize > 0 && hdmemuse(0) >= hdcachesize)
                hdfreecache(PCTFREE, NULL);     /* free some space */
        if (hp->bl[i] == NULL) {                /* allocate (and load) */
                n = hp->bi[i].nrd + nr;
                hp->bl[i] = (BEAM *)hdrealloc(NULL, hdbsiz(n), "hdnewrays");
                blglob(hp)->nrm += n;
                if ((n = hp->bl[i]->nrm = hp->bi[i].nrd)) {
                        errno = 0;
                        if (lseek(hp->fd, hp->bi[i].fo, 0) < 0)
                                error(SYSTEM, "seek error on holodeck file");
                        n *= sizeof(RAYVAL);
                        if (read(hp->fd, (char *)hdbray(hp->bl[i]), n) != n)
                                error(SYSTEM,
                                "error reading beam from holodeck file");
                }
        } else {                                /* just grow in memory */
                hp->bl[i] = (BEAM *)hdrealloc((char *)hp->bl[i],
                                hdbsiz(hp->bl[i]->nrm + nr), "hdnewrays");
                blglob(hp)->nrm += nr;
        }
        if (hdfragflags&FF_ALLOC && hp->bi[i].nrd)
                hdfreefrag(hp, i);              /* relinquish old fragment */
        p = hdbray(hp->bl[i]) + hp->bl[i]->nrm;
        hp->bl[i]->nrm += nr;                   /* update in-core structure */
        bzero((char *)p, nr*sizeof(RAYVAL));
        blglob(hp)->tick = hp->bl[i]->tick = hdclock++; /* update LRU clock */
        return(p);                              /* point to new rays */
}


BEAM *
hdgetbeam(hp, i)        /* get beam (from file if necessary) */
register HOLO   *hp;
register int    i;
{
        register int    n;

        CHECK(i < 1 | i > nbeams(hp),
                        CONSISTENCY, "bad beam index given to hdgetbeam");
        if (hp->bl[i] == NULL) {                /* load from disk */
                if (!(n = hp->bi[i].nrd))
                        return(NULL);
                if (hdcachesize > 0 && hdmemuse(0) >= hdcachesize)
                        hdfreecache(PCTFREE, NULL);     /* get free space */
                hp->bl[i] = (BEAM *)hdrealloc(NULL, hdbsiz(n), "hdgetbeam");
                blglob(hp)->nrm += hp->bl[i]->nrm = n;
                errno = 0;
                if (lseek(hp->fd, hp->bi[i].fo, 0) < 0)
                        error(SYSTEM, "seek error on holodeck file");
                n *= sizeof(RAYVAL);
                if (read(hp->fd, (char *)hdbray(hp->bl[i]), n) != n)
                        error(SYSTEM, "error reading beam from holodeck file");
                if (hdfragflags&FF_READ)
                        hdfreefrag(hp, i);      /* relinquish old frag. */
        }
        blglob(hp)->tick = hp->bl[i]->tick = hdclock++; /* update LRU clock */
        return(hp->bl[i]);
}


int
hdfilord(hb1, hb2)      /* order beams for quick loading */
register HDBEAMI        *hb1, *hb2;
{
        register long   c;
                                /* residents go first */
        if (hb2->h->bl[hb2->b] != NULL)
                return(hb1->h->bl[hb1->b] == NULL);
        if (hb1->h->bl[hb1->b] != NULL)
                return(-1);
                                /* otherwise sort by file descriptor */
        if ((c = hb1->h->fd - hb2->h->fd))
                return(c);
                                /* then by position in file */
        c = hb1->h->bi[hb1->b].fo - hb2->h->bi[hb2->b].fo;
        return(c > 0 ? 1 : c < 0 ? -1 : 0);
}


hdloadbeams(hb, n, bf)  /* load a list of beams in optimal order */
register HDBEAMI        *hb;    /* list gets sorted by hdfilord() */
int     n;                      /* list length */
int     (*bf)();                /* callback function (optional) */
{
        unsigned        origcachesize, memuse;
        int     bytesloaded, needbytes, bytes2free;
        register BEAM   *bp;
        register int    i;
                                        /* precheck consistency */
        if (n <= 0) return;
        for (i = n; i--; )
                if (hb[i].h==NULL || hb[i].b<1 | hb[i].b>nbeams(hb[i].h))
                        error(CONSISTENCY, "bad beam in hdloadbeams");
                                        /* sort list for optimal access */
        qsort((char *)hb, n, sizeof(HDBEAMI), hdfilord);
        bytesloaded = 0;                /* run through loaded beams */
        for ( ; n && (bp = hb->h->bl[hb->b]) != NULL; n--, hb++) {
                bp->tick = hdclock;     /* preempt swap */
                bytesloaded += bp->nrm;
                if (bf != NULL)
                        (*bf)(bp, hb);
        }
        bytesloaded *= sizeof(RAYVAL);
        if ((origcachesize = hdcachesize) > 0) {
                needbytes = 0;          /* figure out memory needs */
                for (i = n; i--; )
                        needbytes += hb[i].h->bi[hb[i].b].nrd;
                needbytes *= sizeof(RAYVAL);
                do {                            /* free enough memory */
                        memuse = hdmemuse(0);
                        bytes2free = needbytes - (int)(hdcachesize-memuse);
                        if (bytes2free > (int)(memuse - bytesloaded))
                                bytes2free = memuse - bytesloaded;
                } while (bytes2free > 0 &&
                                hdfreecache(100*bytes2free/memuse, NULL) < 0);
                hdcachesize = 0;                /* load beams w/o swap */
        }
        for (i = 0; i < n; i++)
                if ((bp = hdgetbeam(hb[i].h, hb[i].b)) != NULL && bf != NULL)
                        (*bf)(bp, hb+i);
        hdcachesize = origcachesize;    /* resume dynamic swapping */
}


int
hdfreefrag(hp, i)                       /* free a file fragment */
HOLO    *hp;
int     i;
{
        register BEAMI  *bi = &hp->bi[i];
        register struct fraglist        *f;
        register int    j, k;

        if (bi->nrd <= 0)
                return(0);
        DCHECK(hp->fd < 0 | hp->fd >= nhdfragls || !hdfragl[hp->fd].nlinks,
                        CONSISTENCY, "bad file descriptor in hdfreefrag");
        f = &hdfragl[hp->fd];
        if (!f->writable)
                return(0);
        if (f->nfrags % FRAGBLK == 0) { /* delete empty remnants */
                for (j = k = 0; k < f->nfrags; j++, k++) {
                        while (f->fi[k].nrd == 0)
                                if (++k >= f->nfrags)
                                        goto endloop;
                        if (k > j)
                                copystruct(f->fi+j, f->fi+k);
                }
        endloop:
                f->nfrags = j;
        }
        j = f->nfrags++;                /* allocate a slot in free list */
#if MAXFRAGB
        if (j >= MAXFRAGB*FRAGBLK) {
                f->nfrags = j--;        /* stop list growth */
                if (bi->nrd <= f->fi[j].nrd)
                        return(0);      /* new one no better than discard */
        }
#endif
        if (j % FRAGBLK == 0) {         /* more (or less) free list space */
                register BEAMI  *newp;
                if (f->fi == NULL)
                        newp = (BEAMI *)malloc((j+FRAGBLK)*sizeof(BEAMI));
                else
                        newp = (BEAMI *)realloc((char *)f->fi,
                                        (j+FRAGBLK)*sizeof(BEAMI));
                if (newp == NULL) {
                        f->nfrags--;    /* graceful failure */
                        return(0);
                }
                f->fi = newp;
        }
        for ( ; ; j--) {                /* insert in descending list */
                if (!j || bi->fo < f->fi[j-1].fo) {
                        f->fi[j].fo = bi->fo;
                        f->fi[j].nrd = bi->nrd;
                        break;
                }
                copystruct(f->fi+j, f->fi+(j-1));
        }
                                        /* coalesce adjacent fragments */
                                                /* successors never empty */
        if (j && f->fi[j-1].fo == f->fi[j].fo + f->fi[j].nrd*sizeof(RAYVAL)) {
                f->fi[j].nrd += f->fi[j-1].nrd;
                f->fi[j-1].nrd = 0;
        }
        for (k = j+1; k < f->nfrags; k++)       /* get non-empty predecessor */
                if (f->fi[k].nrd) {
                        if (f->fi[j].fo == f->fi[k].fo +
                                        f->fi[k].nrd*sizeof(RAYVAL)) {
                                f->fi[k].nrd += f->fi[j].nrd;
                                f->fi[j].nrd = 0;
                        }
                        break;
                }
        biglob(hp)->nrd -= bi->nrd;             /* tell fragment it's free */
        bi->nrd = 0;
        bi->fo = 0L;
        hdmarkdirty(hp, i);                     /* assume we'll reallocate */
        return(1);
}


int
hdfragOK(fd, listlen, listsiz)  /* get fragment list status for file */
int     fd;
int     *listlen;
register int4   *listsiz;
{
        register struct fraglist        *f;
        register int    i;

        if (fd < 0 | fd >= nhdfragls || !(f = &hdfragl[fd])->nlinks)
                return(0);              /* listless */
        if (listlen != NULL)
                *listlen = f->nfrags;
        if (listsiz != NULL)
                for (i = f->nfrags, *listsiz = 0; i--; )
                        *listsiz += f->fi[i].nrd;
#if MAXFRAGB
        return(f->nfrags < MAXFRAGB*FRAGBLK);
#else
        return(1);                      /* list never fills up */
#endif
}


long
hdallocfrag(fd, nrays)          /* allocate a file fragment */
int     fd;
unsigned int4   nrays;
{
        register struct fraglist        *f;
        register int    j;
        long    nfo;

        if (nrays == 0)
                return(-1L);
        DCHECK(fd < 0 | fd >= nhdfragls || !hdfragl[fd].nlinks,
                        CONSISTENCY, "bad file descriptor in hdallocfrag");
        f = &hdfragl[fd];
        for (j = f->nfrags; j-- > 0; )  /* first fit algorithm */
                if (f->fi[j].nrd >= nrays)
                        break;
        if (j < 0) {                    /* no fragment -- extend file */
                nfo = f->flen;
                f->flen += nrays*sizeof(RAYVAL);
        } else {                        /* else use fragment */
                nfo = f->fi[j].fo;
                f->fi[j].fo += nrays*sizeof(RAYVAL);
                f->fi[j].nrd -= nrays;
        }
        return(nfo);
}


int
hdsyncbeam(hp, i)               /* sync beam in memory with beam on disk */
register HOLO   *hp;
register int    i;
{
        int     fragfreed;
        unsigned int4   nrays;
        unsigned int    n;
        long    nfo;
                                        /* check file status */
        if (hdfragl[hp->fd].writable <= 0)
                return(hdfragl[hp->fd].writable);
        DCHECK(i < 1 | i > nbeams(hp),
                        CONSISTENCY, "bad beam index in hdsyncbeam");
                                        /* is current fragment OK? */
        if (hp->bl[i] == NULL || (nrays = hp->bl[i]->nrm) == hp->bi[i].nrd)
                return(0);
                                        /* relinquish old fragment? */
        fragfreed = hdfragflags&FF_WRITE && hp->bi[i].nrd && hdfreefrag(hp,i);
        if (nrays) {                    /* get and write new fragment */
                nfo = hdallocfrag(hp->fd, nrays);
                errno = 0;
                if (lseek(hp->fd, nfo, 0) < 0)
                        error(SYSTEM, "cannot seek on holodeck file");
                n = hp->bl[i]->nrm * sizeof(RAYVAL);
                if (write(hp->fd, (char *)hdbray(hp->bl[i]), n) != n) {
                        hdfragl[hp->fd].writable = -1;
                        hdsync(NULL, 0);        /* sync directories */
                        error(SYSTEM, "write error in hdsyncbeam");
                }
                hp->bi[i].fo = nfo;
        } else
                hp->bi[i].fo = 0L;
        biglob(hp)->nrd += nrays - hp->bi[i].nrd;
        hp->bi[i].nrd = nrays;
        if (!fragfreed)
                hdmarkdirty(hp, i);             /* need to flag dir. ent. */
        return(1);
}


int
hdfreebeam(hp, i)               /* free beam, writing if dirty */
register HOLO   *hp;
register int    i;
{
        int     nchanged;

        if (hp == NULL) {               /* clear all holodecks */
                nchanged = 0;
                for (i = 0; hdlist[i] != NULL; i++)
                        nchanged += hdfreebeam(hdlist[i], 0);
                return(nchanged);
        }
        if (hdfragl[hp->fd].writable < 0)       /* check for file error */
                return(0);
        if (i == 0) {                   /* clear entire holodeck */
                if (blglob(hp)->nrm == 0)
                        return(0);              /* already clear */
                nchanged = 0;
                for (i = nbeams(hp); i > 0; i--)
                        if (hp->bl[i] != NULL)
                                nchanged += hdfreebeam(hp, i);
                DCHECK(blglob(hp)->nrm != 0,
                                CONSISTENCY, "bad beam count in hdfreebeam");
                return(nchanged);
        }
        DCHECK(i < 1 | i > nbeams(hp),
                        CONSISTENCY, "bad beam index to hdfreebeam");
        if (hp->bl[i] == NULL)
                return(0);
                                        /* check for additions */
        nchanged = hp->bl[i]->nrm - hp->bi[i].nrd;
        if (nchanged)
                hdsyncbeam(hp, i);              /* write new fragment */
        blglob(hp)->nrm -= hp->bl[i]->nrm;
        free((char *)hp->bl[i]);                /* free memory */
        hp->bl[i] = NULL;
        return(nchanged);
}


int
hdkillbeam(hp, i)               /* delete beam from holodeck */
register HOLO   *hp;
register int    i;
{
        int     nchanged;

        if (hp == NULL) {               /* clobber all holodecks */
                nchanged = 0;
                for (i = 0; hdlist[i] != NULL; i++)
                        nchanged += hdkillbeam(hdlist[i], 0);
                return(nchanged);
        }
        if (i == 0) {                   /* clobber entire holodeck */
                if (biglob(hp)->nrd == 0 & blglob(hp)->nrm == 0)
                        return(0);              /* already empty */
                nchanged = 0;
                nchanged = 0;
                for (i = nbeams(hp); i > 0; i--)
                        if (hp->bi[i].nrd > 0 || hp->bl[i] != NULL)
                                nchanged += hdkillbeam(hp, i);
                DCHECK(biglob(hp)->nrd != 0 | blglob(hp)->nrm != 0,
                                CONSISTENCY, "bad beam count in hdkillbeam");
                return(nchanged);
        }
        DCHECK(i < 1 | i > nbeams(hp), CONSISTENCY,
                        "bad beam index to hdkillbeam");
        DCHECK(!hdfragl[hp->fd].writable, CONSISTENCY,
                        "hdkillbeam called on read-only holodeck");
        if (hp->bl[i] != NULL) {        /* free memory */
                blglob(hp)->nrm -= nchanged = hp->bl[i]->nrm;
                free((char *)hp->bl[i]);
                hp->bl[i] = NULL;
        } else
                nchanged = hp->bi[i].nrd;
        if (hp->bi[i].nrd && !(hdfragflags&FF_KILL && hdfreefrag(hp,i))) {
                biglob(hp)->nrd -= hp->bi[i].nrd;       /* free failed */
                hp->bi[i].nrd = 0;
                hp->bi[i].fo = 0L;
                hdmarkdirty(hp, i);
        }
        return(nchanged);
}


int
hdlrulist(hb, nents, n, hp)     /* add beams from holodeck to LRU list */
register HDBEAMI        *hb;            /* beam list */
int     nents;                          /* current list length */
int     n;                              /* maximum list length */
register HOLO   *hp;                    /* section we're adding from */
{
        register int    i, j;
                                        /* insert each beam from hp */
        for (i = 1; i <= nbeams(hp); i++) {
                if (hp->bl[i] == NULL)          /* check if loaded */
                        continue;
#if 0
                if (hp->bl[i]->tick == hdclock) /* preempt swap? */
                        continue;
#endif
                if ((j = ++nents) >= n)         /* grow list if we can */
                        nents--;
                for ( ; ; ) {                   /* bubble into place */
                        if (!--j || hp->bl[i]->tick >=
                                        hb[j-1].h->bl[hb[j-1].b]->tick) {
                                hb[j].h = hp;
                                hb[j].b = i;
                                break;
                        }
                        copystruct(hb+j, hb+(j-1));
                }
        }
        return(nents);                  /* return new list length */
}


int
hdfreecache(pct, honly)         /* free up cache space, writing changes */
int     pct;                            /* maximum percentage to free */
register HOLO   *honly;                 /* NULL means check all */
{
        HDBEAMI hb[FREEBEAMS];
        int     freetarget;
        int     n;
        register int    i;
#ifdef DEBUG
        unsigned        membefore;

        membefore = hdmemuse(0);
#endif
                                                /* compute free target */
        freetarget = (honly != NULL) ? blglob(honly)->nrm :
                        hdmemuse(0)/sizeof(RAYVAL) ;
        freetarget = freetarget*pct/100;
        if (freetarget <= 0)
                return(0);
                                                /* find least recently used */
        n = 0;
        if (honly != NULL)
                n = hdlrulist(hb, n, FREEBEAMS, honly);
        else
                for (i = 0; hdlist[i] != NULL; i++)
                        n = hdlrulist(hb, n, FREEBEAMS, hdlist[i]);
                                                /* free LRU beams */
        for (i = 0; i < n; i++) {
                hdfreebeam(hb[i].h, hb[i].b);
                if ((freetarget -= hb[i].h->bi[hb[i].b].nrd) <= 0)
                        break;
        }
        hdsync(honly, 0);       /* synchronize directories as necessary */
#ifdef DEBUG
        sprintf(errmsg,
        "%dK before, %dK after hdfreecache (%dK total), %d rays short\n",
                membefore>>10, hdmemuse(0)>>10, hdmemuse(1)>>10, freetarget);
        wputs(errmsg);
#endif
        return(-freetarget);    /* return how far past goal we went */
}


hddone(hp)              /* clean up holodeck section and free */
register HOLO   *hp;            /* NULL means clean up all */
{
        register int    i;

        if (hp == NULL) {               /* NULL means clean up everything */
                while (hdlist[0] != NULL)
                        hddone(hdlist[0]);
                free((char *)hdfragl);
                hdfragl = NULL; nhdfragls = 0;
                return;
        }
                                        /* flush all data and free memory */
        hdflush(hp);
                                        /* release fragment resources */
        hdrelease(hp->fd);
                                        /* remove hp from active list */
        for (i = 0; hdlist[i] != NULL; i++)
                if (hdlist[i] == hp) {
                        while ((hdlist[i] = hdlist[i+1]) != NULL)
                                i++;
                        break;
                }
        free((char *)hp->bl);           /* free beam list */
        free((char *)hp);               /* free holodeck struct */
}
Revision:	3.41
Committed:	Thu Aug 5 15:53:09 1999 UTC (26 years, 2 months ago) by gwlarson
Content type:	text/plain
Branch:	MAIN
Changes since 3.40:	+26 -11 lines
Log Message:	added -r option for read-only holodecks