Subversion Repositories planix.SVN

#include        <u.h>
#include        <libc.h>
#include        <bio.h>

static  Biobufhdr*      wbufs[20];
static  int             atexitflag;

static
void
batexit(void)
{
        Biobufhdr *bp;
        int i;

        for(i=0; i<nelem(wbufs); i++) {
                bp = wbufs[i];
                if(bp != 0) {
                        wbufs[i] = 0;
                        Bflush(bp);
                }
        }
}

static
void
deinstall(Biobufhdr *bp)
{
        int i;

        for(i=0; i<nelem(wbufs); i++)
                if(wbufs[i] == bp)
                        wbufs[i] = 0;
}

static
void
install(Biobufhdr *bp)
{
        int i;

        deinstall(bp);
        for(i=0; i<nelem(wbufs); i++)
                if(wbufs[i] == 0) {
                        wbufs[i] = bp;
                        break;
                }
        if(atexitflag == 0) {
                atexitflag = 1;
                atexit(batexit);
        }
}

int
Binits(Biobufhdr *bp, int f, int mode, uchar *p, int size)
{

        p += Bungetsize;        /* make room for Bungets */
        size -= Bungetsize;

        switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
        default:
                fprint(2, "Binits: unknown mode %d\n", mode);
                return Beof;

        case OREAD:
                bp->state = Bractive;
                bp->ocount = 0;
                break;

        case OWRITE:
                install(bp);
                bp->state = Bwactive;
                bp->ocount = -size;
                break;
        }
        bp->bbuf = p;
        bp->ebuf = p+size;
        bp->bsize = size;
        bp->icount = 0;
        bp->gbuf = bp->ebuf;
        bp->fid = f;
        bp->flag = 0;
        bp->rdline = 0;
        bp->offset = 0;
        bp->runesize = 0;
        return 0;
}


int
Binit(Biobuf *bp, int f, int mode)
{
        return Binits(bp, f, mode, bp->b, sizeof(bp->b));
}

Biobuf*
Bopen(char *name, int mode)
{
        Biobuf *bp;
        int f;

        switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
        default:
                fprint(2, "Bopen: unknown mode %#x\n", mode);
                return 0;
        case OREAD:
                f = open(name, mode);
                break;
        case OWRITE:
                f = create(name, mode, 0666);
                break;
        }
        if(f < 0)
                return 0;
        bp = malloc(sizeof(Biobuf));
        Binits(bp, f, mode, bp->b, sizeof(bp->b));
        bp->flag = Bmagic;                      /* mark bp open & malloced */
        return bp;
}

int
Bterm(Biobufhdr *bp)
{
        int r;

        deinstall(bp);
        r = Bflush(bp);
        if(bp->flag == Bmagic) {
                bp->flag = 0;
                close(bp->fid);
                bp->fid = -1;                   /* prevent accidents */
                free(bp);
        }
        /* otherwise opened with Binit(s) */
        return r;
}