1 056fe1ba 2003-11-23 devnull #include <u.h>
 2 056fe1ba 2003-11-23 devnull #include <libc.h>
 3 056fe1ba 2003-11-23 devnull #include <venti.h>
 4 056fe1ba 2003-11-23 devnull 
 5 056fe1ba 2003-11-23 devnull void
 6 056fe1ba 2003-11-23 devnull vtzeroextend(int type, uchar *buf, uint n, uint nn)
 7 056fe1ba 2003-11-23 devnull {
 8 056fe1ba 2003-11-23 devnull 	uchar *p, *ep;
 9 056fe1ba 2003-11-23 devnull 
10 056fe1ba 2003-11-23 devnull 	switch(type&7) {
11 056fe1ba 2003-11-23 devnull 	case 0:
12 056fe1ba 2003-11-23 devnull 		memset(buf+n, 0, nn-n);
13 056fe1ba 2003-11-23 devnull 		break;
14 056fe1ba 2003-11-23 devnull 	default:
15 056fe1ba 2003-11-23 devnull 		p = buf + (n/VtScoreSize)*VtScoreSize;
16 056fe1ba 2003-11-23 devnull 		ep = buf + (nn/VtScoreSize)*VtScoreSize;
17 056fe1ba 2003-11-23 devnull 		while(p < ep) {
18 056fe1ba 2003-11-23 devnull 			memmove(p, vtzeroscore, VtScoreSize);
19 056fe1ba 2003-11-23 devnull 			p += VtScoreSize;
20 056fe1ba 2003-11-23 devnull 		}
21 056fe1ba 2003-11-23 devnull 		memset(p, 0, buf+nn-p);
22 056fe1ba 2003-11-23 devnull 		break;
23 056fe1ba 2003-11-23 devnull 	}
24 056fe1ba 2003-11-23 devnull }
25 056fe1ba 2003-11-23 devnull 
26 fa325e9b 2020-01-10 cross uint
27 056fe1ba 2003-11-23 devnull vtzerotruncate(int type, uchar *buf, uint n)
28 056fe1ba 2003-11-23 devnull {
29 056fe1ba 2003-11-23 devnull 	uchar *p;
30 056fe1ba 2003-11-23 devnull 
31 056fe1ba 2003-11-23 devnull 	if(type == VtRootType){
32 056fe1ba 2003-11-23 devnull 		if(n < VtRootSize)
33 056fe1ba 2003-11-23 devnull 			return n;
34 056fe1ba 2003-11-23 devnull 		return VtRootSize;
35 056fe1ba 2003-11-23 devnull 	}
36 056fe1ba 2003-11-23 devnull 
37 056fe1ba 2003-11-23 devnull 	switch(type&7){
38 056fe1ba 2003-11-23 devnull 	case 0:
39 056fe1ba 2003-11-23 devnull 		for(p = buf + n; p > buf; p--) {
40 056fe1ba 2003-11-23 devnull 			if(p[-1] != 0)
41 056fe1ba 2003-11-23 devnull 				break;
42 056fe1ba 2003-11-23 devnull 		}
43 056fe1ba 2003-11-23 devnull 		return p - buf;
44 056fe1ba 2003-11-23 devnull 	default:
45 056fe1ba 2003-11-23 devnull 		/* ignore slop at end of block */
46 056fe1ba 2003-11-23 devnull 		p = buf + (n/VtScoreSize)*VtScoreSize;
47 056fe1ba 2003-11-23 devnull 
48 056fe1ba 2003-11-23 devnull 		while(p > buf) {
49 056fe1ba 2003-11-23 devnull 			if(memcmp(p - VtScoreSize, vtzeroscore, VtScoreSize) != 0)
50 056fe1ba 2003-11-23 devnull 				break;
51 056fe1ba 2003-11-23 devnull 			p -= VtScoreSize;
52 056fe1ba 2003-11-23 devnull 		}
53 056fe1ba 2003-11-23 devnull 		return p - buf;
54 056fe1ba 2003-11-23 devnull 	}
55 056fe1ba 2003-11-23 devnull }