1*368c31abSDavid du Colombier #include <u.h>
2*368c31abSDavid du Colombier #include <libc.h>
3*368c31abSDavid du Colombier #include <oventi.h>
4*368c31abSDavid du Colombier
5*368c31abSDavid du Colombier /* score of a zero length block */
6*368c31abSDavid du Colombier uchar vtZeroScore[VtScoreSize] = {
7*368c31abSDavid du Colombier 0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d, 0x32, 0x55,
8*368c31abSDavid du Colombier 0xbf, 0xef, 0x95, 0x60, 0x18, 0x90, 0xaf, 0xd8, 0x07, 0x09
9*368c31abSDavid du Colombier };
10*368c31abSDavid du Colombier
11*368c31abSDavid du Colombier
12*368c31abSDavid du Colombier int
vtZeroExtend(int type,uchar * buf,int n,int nn)13*368c31abSDavid du Colombier vtZeroExtend(int type, uchar *buf, int n, int nn)
14*368c31abSDavid du Colombier {
15*368c31abSDavid du Colombier uchar *p, *ep;
16*368c31abSDavid du Colombier
17*368c31abSDavid du Colombier switch(type) {
18*368c31abSDavid du Colombier default:
19*368c31abSDavid du Colombier memset(buf+n, 0, nn-n);
20*368c31abSDavid du Colombier break;
21*368c31abSDavid du Colombier case VtPointerType0:
22*368c31abSDavid du Colombier case VtPointerType1:
23*368c31abSDavid du Colombier case VtPointerType2:
24*368c31abSDavid du Colombier case VtPointerType3:
25*368c31abSDavid du Colombier case VtPointerType4:
26*368c31abSDavid du Colombier case VtPointerType5:
27*368c31abSDavid du Colombier case VtPointerType6:
28*368c31abSDavid du Colombier case VtPointerType7:
29*368c31abSDavid du Colombier case VtPointerType8:
30*368c31abSDavid du Colombier case VtPointerType9:
31*368c31abSDavid du Colombier p = buf + (n/VtScoreSize)*VtScoreSize;
32*368c31abSDavid du Colombier ep = buf + (nn/VtScoreSize)*VtScoreSize;
33*368c31abSDavid du Colombier while(p < ep) {
34*368c31abSDavid du Colombier memmove(p, vtZeroScore, VtScoreSize);
35*368c31abSDavid du Colombier p += VtScoreSize;
36*368c31abSDavid du Colombier }
37*368c31abSDavid du Colombier memset(p, 0, buf+nn-p);
38*368c31abSDavid du Colombier break;
39*368c31abSDavid du Colombier }
40*368c31abSDavid du Colombier return 1;
41*368c31abSDavid du Colombier }
42*368c31abSDavid du Colombier
43*368c31abSDavid du Colombier int
vtZeroTruncate(int type,uchar * buf,int n)44*368c31abSDavid du Colombier vtZeroTruncate(int type, uchar *buf, int n)
45*368c31abSDavid du Colombier {
46*368c31abSDavid du Colombier uchar *p;
47*368c31abSDavid du Colombier
48*368c31abSDavid du Colombier switch(type) {
49*368c31abSDavid du Colombier default:
50*368c31abSDavid du Colombier for(p = buf + n; p > buf; p--) {
51*368c31abSDavid du Colombier if(p[-1] != 0)
52*368c31abSDavid du Colombier break;
53*368c31abSDavid du Colombier }
54*368c31abSDavid du Colombier return p - buf;
55*368c31abSDavid du Colombier case VtRootType:
56*368c31abSDavid du Colombier if(n < VtRootSize)
57*368c31abSDavid du Colombier return n;
58*368c31abSDavid du Colombier return VtRootSize;
59*368c31abSDavid du Colombier case VtPointerType0:
60*368c31abSDavid du Colombier case VtPointerType1:
61*368c31abSDavid du Colombier case VtPointerType2:
62*368c31abSDavid du Colombier case VtPointerType3:
63*368c31abSDavid du Colombier case VtPointerType4:
64*368c31abSDavid du Colombier case VtPointerType5:
65*368c31abSDavid du Colombier case VtPointerType6:
66*368c31abSDavid du Colombier case VtPointerType7:
67*368c31abSDavid du Colombier case VtPointerType8:
68*368c31abSDavid du Colombier case VtPointerType9:
69*368c31abSDavid du Colombier /* ignore slop at end of block */
70*368c31abSDavid du Colombier p = buf + (n/VtScoreSize)*VtScoreSize;
71*368c31abSDavid du Colombier
72*368c31abSDavid du Colombier while(p > buf) {
73*368c31abSDavid du Colombier if(memcmp(p - VtScoreSize, vtZeroScore, VtScoreSize) != 0)
74*368c31abSDavid du Colombier break;
75*368c31abSDavid du Colombier p -= VtScoreSize;
76*368c31abSDavid du Colombier }
77*368c31abSDavid du Colombier return p - buf;
78*368c31abSDavid du Colombier }
79*368c31abSDavid du Colombier }
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