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 5f6612ba 2008-05-31 rsc long long
 5 5f6612ba 2008-05-31 rsc Bseek(Biobuf *bp, long long offset, int base)
 6 b2cfc4e2 2003-09-30 devnull {
 7 75a69d3b 2004-06-16 devnull 	vlong n, d;
 8 39ef727f 2004-06-16 devnull 	int bufsz;
 9 b2cfc4e2 2003-09-30 devnull 
10 b2cfc4e2 2003-09-30 devnull 	switch(bp->state) {
11 b2cfc4e2 2003-09-30 devnull 	default:
12 b2cfc4e2 2003-09-30 devnull 		fprint(2, "Bseek: unknown state %d\n", bp->state);
13 b2cfc4e2 2003-09-30 devnull 		return Beof;
14 b2cfc4e2 2003-09-30 devnull 
15 b2cfc4e2 2003-09-30 devnull 	case Bracteof:
16 b2cfc4e2 2003-09-30 devnull 		bp->state = Bractive;
17 b2cfc4e2 2003-09-30 devnull 		bp->icount = 0;
18 b2cfc4e2 2003-09-30 devnull 		bp->gbuf = bp->ebuf;
19 b2cfc4e2 2003-09-30 devnull 
20 b2cfc4e2 2003-09-30 devnull 	case Bractive:
21 b2cfc4e2 2003-09-30 devnull 		n = offset;
22 b2cfc4e2 2003-09-30 devnull 		if(base == 1) {
23 b2cfc4e2 2003-09-30 devnull 			n += Boffset(bp);
24 b2cfc4e2 2003-09-30 devnull 			base = 0;
25 b2cfc4e2 2003-09-30 devnull 		}
26 b2cfc4e2 2003-09-30 devnull 
27 b2cfc4e2 2003-09-30 devnull 		/*
28 b2cfc4e2 2003-09-30 devnull 		 * try to seek within buffer
29 b2cfc4e2 2003-09-30 devnull 		 */
30 b2cfc4e2 2003-09-30 devnull 		if(base == 0) {
31 b2cfc4e2 2003-09-30 devnull 			d = n - Boffset(bp);
32 39ef727f 2004-06-16 devnull 			bufsz = bp->ebuf - bp->gbuf;
33 39ef727f 2004-06-16 devnull 			if(-bufsz <= d && d <= bufsz){
34 39ef727f 2004-06-16 devnull 				bp->icount += d;
35 39ef727f 2004-06-16 devnull 				if(d >= 0) {
36 39ef727f 2004-06-16 devnull 					if(bp->icount <= 0)
37 39ef727f 2004-06-16 devnull 						return n;
38 39ef727f 2004-06-16 devnull 				} else {
39 39ef727f 2004-06-16 devnull 					if(bp->ebuf - bp->gbuf >= -bp->icount)
40 39ef727f 2004-06-16 devnull 						return n;
41 39ef727f 2004-06-16 devnull 				}
42 b2cfc4e2 2003-09-30 devnull 			}
43 b2cfc4e2 2003-09-30 devnull 		}
44 b2cfc4e2 2003-09-30 devnull 
45 b2cfc4e2 2003-09-30 devnull 		/*
46 b2cfc4e2 2003-09-30 devnull 		 * reset the buffer
47 b2cfc4e2 2003-09-30 devnull 		 */
48 b2cfc4e2 2003-09-30 devnull 		n = lseek(bp->fid, n, base);
49 b2cfc4e2 2003-09-30 devnull 		bp->icount = 0;
50 b2cfc4e2 2003-09-30 devnull 		bp->gbuf = bp->ebuf;
51 b2cfc4e2 2003-09-30 devnull 		break;
52 b2cfc4e2 2003-09-30 devnull 
53 b2cfc4e2 2003-09-30 devnull 	case Bwactive:
54 b2cfc4e2 2003-09-30 devnull 		Bflush(bp);
55 5f6612ba 2008-05-31 rsc 		n = seek(bp->fid, offset, base);
56 b2cfc4e2 2003-09-30 devnull 		break;
57 b2cfc4e2 2003-09-30 devnull 	}
58 b2cfc4e2 2003-09-30 devnull 	bp->offset = n;
59 b2cfc4e2 2003-09-30 devnull 	return n;
60 b2cfc4e2 2003-09-30 devnull }