1 b2cfc4e2 2003-09-30 devnull #include	"lib9.h"
 2 b2cfc4e2 2003-09-30 devnull #include	<bio.h>
 3 b2cfc4e2 2003-09-30 devnull 
 4 b2cfc4e2 2003-09-30 devnull off_t
 5 b2cfc4e2 2003-09-30 devnull Bseek(Biobuf *bp, off_t offset, int base)
 6 b2cfc4e2 2003-09-30 devnull {
 7 b2cfc4e2 2003-09-30 devnull 	off_t n, d;
 8 b2cfc4e2 2003-09-30 devnull 
 9 b2cfc4e2 2003-09-30 devnull 	switch(bp->state) {
10 b2cfc4e2 2003-09-30 devnull 	default:
11 b2cfc4e2 2003-09-30 devnull 		fprint(2, "Bseek: unknown state %d\n", bp->state);
12 b2cfc4e2 2003-09-30 devnull 		return Beof;
13 b2cfc4e2 2003-09-30 devnull 
14 b2cfc4e2 2003-09-30 devnull 	case Bracteof:
15 b2cfc4e2 2003-09-30 devnull 		bp->state = Bractive;
16 b2cfc4e2 2003-09-30 devnull 		bp->icount = 0;
17 b2cfc4e2 2003-09-30 devnull 		bp->gbuf = bp->ebuf;
18 b2cfc4e2 2003-09-30 devnull 
19 b2cfc4e2 2003-09-30 devnull 	case Bractive:
20 b2cfc4e2 2003-09-30 devnull 		n = offset;
21 b2cfc4e2 2003-09-30 devnull 		if(base == 1) {
22 b2cfc4e2 2003-09-30 devnull 			n += Boffset(bp);
23 b2cfc4e2 2003-09-30 devnull 			base = 0;
24 b2cfc4e2 2003-09-30 devnull 		}
25 b2cfc4e2 2003-09-30 devnull 
26 b2cfc4e2 2003-09-30 devnull 		/*
27 b2cfc4e2 2003-09-30 devnull 		 * try to seek within buffer
28 b2cfc4e2 2003-09-30 devnull 		 */
29 b2cfc4e2 2003-09-30 devnull 		if(base == 0) {
30 b2cfc4e2 2003-09-30 devnull 			d = n - Boffset(bp);
31 b2cfc4e2 2003-09-30 devnull 			bp->icount += d;
32 b2cfc4e2 2003-09-30 devnull 			if(d >= 0) {
33 b2cfc4e2 2003-09-30 devnull 				if(bp->icount <= 0)
34 b2cfc4e2 2003-09-30 devnull 					return n;
35 b2cfc4e2 2003-09-30 devnull 			} else {
36 b2cfc4e2 2003-09-30 devnull 				if(bp->ebuf - bp->gbuf >= -bp->icount)
37 b2cfc4e2 2003-09-30 devnull 					return n;
38 b2cfc4e2 2003-09-30 devnull 			}
39 b2cfc4e2 2003-09-30 devnull 		}
40 b2cfc4e2 2003-09-30 devnull 
41 b2cfc4e2 2003-09-30 devnull 		/*
42 b2cfc4e2 2003-09-30 devnull 		 * reset the buffer
43 b2cfc4e2 2003-09-30 devnull 		 */
44 b2cfc4e2 2003-09-30 devnull 		n = lseek(bp->fid, n, base);
45 b2cfc4e2 2003-09-30 devnull 		bp->icount = 0;
46 b2cfc4e2 2003-09-30 devnull 		bp->gbuf = bp->ebuf;
47 b2cfc4e2 2003-09-30 devnull 		break;
48 b2cfc4e2 2003-09-30 devnull 
49 b2cfc4e2 2003-09-30 devnull 	case Bwactive:
50 b2cfc4e2 2003-09-30 devnull 		Bflush(bp);
51 b2cfc4e2 2003-09-30 devnull 		n = lseek(bp->fid, offset, base);
52 b2cfc4e2 2003-09-30 devnull 		break;
53 b2cfc4e2 2003-09-30 devnull 	}
54 b2cfc4e2 2003-09-30 devnull 	bp->offset = n;
55 b2cfc4e2 2003-09-30 devnull 	return n;
56 b2cfc4e2 2003-09-30 devnull }