1 d957951b 2005-02-11 devnull #include <u.h>
2 d957951b 2005-02-11 devnull #include <libc.h>
3 d957951b 2005-02-11 devnull #include <bio.h>
4 d957951b 2005-02-11 devnull #include <ndb.h>
7 d957951b 2005-02-11 devnull * make the hash table completely in memory and then write as a file
10 d957951b 2005-02-11 devnull uchar *ht;
11 d957951b 2005-02-11 devnull ulong hlen;
13 d957951b 2005-02-11 devnull ulong nextchain;
16 d957951b 2005-02-11 devnull syserr(void)
18 d957951b 2005-02-11 devnull static char buf[ERRMAX];
20 d957951b 2005-02-11 devnull errstr(buf, sizeof buf);
21 d957951b 2005-02-11 devnull return buf;
25 d957951b 2005-02-11 devnull enter(char *val, ulong dboff)
28 d957951b 2005-02-11 devnull uchar *last;
29 d957951b 2005-02-11 devnull ulong ptr;
31 d957951b 2005-02-11 devnull h = ndbhash(val, hlen);
32 d957951b 2005-02-11 devnull h *= NDBPLEN;
33 d957951b 2005-02-11 devnull last = &ht[h];
34 d957951b 2005-02-11 devnull ptr = NDBGETP(last);
35 d957951b 2005-02-11 devnull if(ptr == NDBNAP){
36 d957951b 2005-02-11 devnull NDBPUTP(dboff, last);
40 d957951b 2005-02-11 devnull if(ptr & NDBCHAIN){
41 d957951b 2005-02-11 devnull /* walk the chain to the last entry */
43 d957951b 2005-02-11 devnull ptr &= ~NDBCHAIN;
44 d957951b 2005-02-11 devnull last = &ht[ptr+NDBPLEN];
45 d957951b 2005-02-11 devnull ptr = NDBGETP(last);
46 d957951b 2005-02-11 devnull if(ptr == NDBNAP){
47 d957951b 2005-02-11 devnull NDBPUTP(dboff, last);
50 d957951b 2005-02-11 devnull if(!(ptr & NDBCHAIN)){
51 d957951b 2005-02-11 devnull NDBPUTP(nextchain|NDBCHAIN, last);
56 d957951b 2005-02-11 devnull NDBPUTP(nextchain|NDBCHAIN, last);
58 d957951b 2005-02-11 devnull /* add a chained entry */
59 d957951b 2005-02-11 devnull NDBPUTP(ptr, &ht[nextchain]);
60 d957951b 2005-02-11 devnull NDBPUTP(dboff, &ht[nextchain + NDBPLEN]);
61 d957951b 2005-02-11 devnull nextchain += 2*NDBPLEN;
64 d957951b 2005-02-11 devnull uchar nbuf[16*1024];
67 d957951b 2005-02-11 devnull main(int argc, char **argv)
69 d957951b 2005-02-11 devnull Ndbtuple *t, *nt;
72 d957951b 2005-02-11 devnull uchar buf[8];
73 d957951b 2005-02-11 devnull char file[128];
75 d957951b 2005-02-11 devnull ulong off;
76 d957951b 2005-02-11 devnull uchar *p;
78 d957951b 2005-02-11 devnull if(argc != 3){
79 d957951b 2005-02-11 devnull fprint(2, "mkhash: usage file attribute\n");
80 d957951b 2005-02-11 devnull exits("usage");
82 d957951b 2005-02-11 devnull db = ndbopen(argv[1]);
83 d957951b 2005-02-11 devnull if(db == 0){
84 d957951b 2005-02-11 devnull fprint(2, "mkhash: can't open %s\n", argv[1]);
85 d957951b 2005-02-11 devnull exits(syserr());
88 d957951b 2005-02-11 devnull /* try a bigger than normal buffer */
89 d957951b 2005-02-11 devnull Binits(&db->b, Bfildes(&db->b), OREAD, nbuf, sizeof(nbuf));
91 d957951b 2005-02-11 devnull /* count entries to calculate hash size */
94 d957951b 2005-02-11 devnull while(nt = ndbparse(db)){
95 d957951b 2005-02-11 devnull for(t = nt; t; t = t->entry){
96 d957951b 2005-02-11 devnull if(strcmp(t->attr, argv[2]) == 0)
99 d957951b 2005-02-11 devnull ndbfree(nt);
102 d957951b 2005-02-11 devnull /* allocate an array large enough for worst case */
103 d957951b 2005-02-11 devnull hlen = 2*n+1;
104 d957951b 2005-02-11 devnull n = hlen*NDBPLEN + hlen*2*NDBPLEN;
105 d957951b 2005-02-11 devnull ht = mallocz(n, 1);
106 d957951b 2005-02-11 devnull if(ht == 0){
107 d957951b 2005-02-11 devnull fprint(2, "mkhash: not enough memory\n");
108 d957951b 2005-02-11 devnull exits(syserr());
110 d957951b 2005-02-11 devnull for(p = ht; p < &ht[n]; p += NDBPLEN)
111 d957951b 2005-02-11 devnull NDBPUTP(NDBNAP, p);
112 d957951b 2005-02-11 devnull nextchain = hlen*NDBPLEN;
114 d957951b 2005-02-11 devnull /* create the in core hash table */
115 d957951b 2005-02-11 devnull Bseek(&db->b, 0, 0);
116 d957951b 2005-02-11 devnull off = 0;
117 d957951b 2005-02-11 devnull while(nt = ndbparse(db)){
118 d957951b 2005-02-11 devnull for(t = nt; t; t = t->entry){
119 d957951b 2005-02-11 devnull if(strcmp(t->attr, argv[2]) == 0)
120 d957951b 2005-02-11 devnull enter(t->val, off);
122 d957951b 2005-02-11 devnull ndbfree(nt);
123 d957951b 2005-02-11 devnull off = Boffset(&db->b);
126 d957951b 2005-02-11 devnull /* create the hash file */
127 d957951b 2005-02-11 devnull snprint(file, sizeof(file), "%s.%s", argv[1], argv[2]);
128 d957951b 2005-02-11 devnull fd = create(file, ORDWR, 0664);
129 d957951b 2005-02-11 devnull if(fd < 0){
130 d957951b 2005-02-11 devnull fprint(2, "mkhash: can't create %s\n", file);
131 d957951b 2005-02-11 devnull exits(syserr());
133 d957951b 2005-02-11 devnull NDBPUTUL(db->mtime, buf);
134 d957951b 2005-02-11 devnull NDBPUTUL(hlen, buf+NDBULLEN);
135 d957951b 2005-02-11 devnull if(write(fd, buf, NDBHLEN) != NDBHLEN){
136 d957951b 2005-02-11 devnull fprint(2, "mkhash: writing %s\n", file);
137 d957951b 2005-02-11 devnull exits(syserr());
139 d957951b 2005-02-11 devnull if(write(fd, ht, nextchain) != nextchain){
140 d957951b 2005-02-11 devnull fprint(2, "mkhash: writing %s\n", file);
141 d957951b 2005-02-11 devnull exits(syserr());
143 d957951b 2005-02-11 devnull close(fd);
145 d957951b 2005-02-11 devnull /* make sure file didn't change while we were making the hash */
146 d957951b 2005-02-11 devnull d = dirstat(argv[1]);
147 d957951b 2005-02-11 devnull if(d == nil || d->qid.path != db->qid.path
148 d957951b 2005-02-11 devnull || d->qid.vers != db->qid.vers){
149 d957951b 2005-02-11 devnull fprint(2, "mkhash: %s changed underfoot\n", argv[1]);
150 d957951b 2005-02-11 devnull remove(file);
151 d957951b 2005-02-11 devnull exits("changed");
154 d957951b 2005-02-11 devnull exits(0);