1 /* Public domain. */
2
3 #include "seek.h"
4 #include "error.h"
5 #include "alloc.h"
6 #include "cdb.h"
7 #include "cdb_make.h"
8
cdb_make_start(struct cdb_make * c,int fd)9 int cdb_make_start(struct cdb_make *c,int fd)
10 {
11 c->head = 0;
12 c->split = 0;
13 c->hash = 0;
14 c->numentries = 0;
15 c->fd = fd;
16 c->pos = sizeof c->final;
17 buffer_init(&c->b,buffer_unixwrite,fd,c->bspace,sizeof c->bspace);
18 return seek_set(fd,c->pos);
19 }
20
posplus(struct cdb_make * c,uint32 len)21 static int posplus(struct cdb_make *c,uint32 len)
22 {
23 uint32 newpos = c->pos + len;
24 if (newpos < len) { errno = error_nomem; return -1; }
25 c->pos = newpos;
26 return 0;
27 }
28
cdb_make_addend(struct cdb_make * c,unsigned int keylen,unsigned int datalen,uint32 h)29 int cdb_make_addend(struct cdb_make *c,unsigned int keylen,unsigned int datalen,uint32 h)
30 {
31 struct cdb_hplist *head;
32
33 head = c->head;
34 if (!head || (head->num >= CDB_HPLIST)) {
35 head = (struct cdb_hplist *) alloc(sizeof(struct cdb_hplist));
36 if (!head) return -1;
37 head->num = 0;
38 head->next = c->head;
39 c->head = head;
40 }
41 head->hp[head->num].h = h;
42 head->hp[head->num].p = c->pos;
43 ++head->num;
44 ++c->numentries;
45 if (posplus(c,8) == -1) return -1;
46 if (posplus(c,keylen) == -1) return -1;
47 if (posplus(c,datalen) == -1) return -1;
48 return 0;
49 }
50
cdb_make_addbegin(struct cdb_make * c,unsigned int keylen,unsigned int datalen)51 int cdb_make_addbegin(struct cdb_make *c,unsigned int keylen,unsigned int datalen)
52 {
53 char buf[8];
54
55 if (keylen > 0xffffffff) { errno = error_nomem; return -1; }
56 if (datalen > 0xffffffff) { errno = error_nomem; return -1; }
57
58 uint32_pack(buf,keylen);
59 uint32_pack(buf + 4,datalen);
60 if (buffer_putalign(&c->b,buf,8) == -1) return -1;
61 return 0;
62 }
63
cdb_make_add(struct cdb_make * c,const char * key,unsigned int keylen,const char * data,unsigned int datalen)64 int cdb_make_add(struct cdb_make *c,const char *key,unsigned int keylen,const char *data,unsigned int datalen)
65 {
66 if (cdb_make_addbegin(c,keylen,datalen) == -1) return -1;
67 if (buffer_putalign(&c->b,key,keylen) == -1) return -1;
68 if (buffer_putalign(&c->b,data,datalen) == -1) return -1;
69 return cdb_make_addend(c,keylen,datalen,cdb_hash(key,keylen));
70 }
71
cdb_make_finish(struct cdb_make * c)72 int cdb_make_finish(struct cdb_make *c)
73 {
74 char buf[8];
75 int i;
76 uint32 len;
77 uint32 u;
78 uint32 memsize;
79 uint32 count;
80 uint32 where;
81 struct cdb_hplist *x;
82 struct cdb_hp *hp;
83
84 for (i = 0;i < 256;++i)
85 c->count[i] = 0;
86
87 for (x = c->head;x;x = x->next) {
88 i = x->num;
89 while (i--)
90 ++c->count[255 & x->hp[i].h];
91 }
92
93 memsize = 1;
94 for (i = 0;i < 256;++i) {
95 u = c->count[i] * 2;
96 if (u > memsize)
97 memsize = u;
98 }
99
100 memsize += c->numentries; /* no overflow possible up to now */
101 u = (uint32) 0 - (uint32) 1;
102 u /= sizeof(struct cdb_hp);
103 if (memsize > u) { errno = error_nomem; return -1; }
104
105 c->split = (struct cdb_hp *) alloc(memsize * sizeof(struct cdb_hp));
106 if (!c->split) return -1;
107
108 c->hash = c->split + c->numentries;
109
110 u = 0;
111 for (i = 0;i < 256;++i) {
112 u += c->count[i]; /* bounded by numentries, so no overflow */
113 c->start[i] = u;
114 }
115
116 for (x = c->head;x;x = x->next) {
117 i = x->num;
118 while (i--)
119 c->split[--c->start[255 & x->hp[i].h]] = x->hp[i];
120 }
121
122 for (i = 0;i < 256;++i) {
123 count = c->count[i];
124
125 len = count + count; /* no overflow possible */
126 uint32_pack(c->final + 8 * i,c->pos);
127 uint32_pack(c->final + 8 * i + 4,len);
128
129 for (u = 0;u < len;++u)
130 c->hash[u].h = c->hash[u].p = 0;
131
132 hp = c->split + c->start[i];
133 for (u = 0;u < count;++u) {
134 where = (hp->h >> 8) % len;
135 while (c->hash[where].p)
136 if (++where == len)
137 where = 0;
138 c->hash[where] = *hp++;
139 }
140
141 for (u = 0;u < len;++u) {
142 uint32_pack(buf,c->hash[u].h);
143 uint32_pack(buf + 4,c->hash[u].p);
144 if (buffer_putalign(&c->b,buf,8) == -1) return -1;
145 if (posplus(c,8) == -1) return -1;
146 }
147 }
148
149 if (buffer_flush(&c->b) == -1) return -1;
150 if (seek_begin(c->fd) == -1) return -1;
151 return buffer_putflush(&c->b,c->final,sizeof c->final);
152 }
153