Commit | Line | Data |
---|---|---|
dc7ddb87 MW |
1 | /* Public domain. */ |
2 | /* Adapted from DJB's original cdb-0.75 package */ | |
3 | ||
4 | #include <sys/types.h> | |
5 | #include <sys/stat.h> | |
6 | #include <sys/mman.h> | |
7 | #include <unistd.h> | |
8 | #include <string.h> | |
9 | #include <errno.h> | |
10 | #include "cdb.h" | |
11 | ||
12 | #ifndef EPROTO | |
13 | #define EPROTO -15 /* cdb 0.75's default for PROTOless systems */ | |
14 | #endif | |
15 | ||
16 | void cdb_free(struct cdb *c) | |
17 | { | |
18 | if (c->map) { | |
19 | munmap(c->map,c->size); | |
20 | c->map = 0; | |
21 | } | |
22 | } | |
23 | ||
24 | void cdb_findstart(struct cdb *c) | |
25 | { | |
26 | c->loop = 0; | |
27 | } | |
28 | ||
29 | void cdb_init(struct cdb *c,int fd) | |
30 | { | |
31 | struct stat st; | |
32 | char *x; | |
33 | ||
34 | cdb_free(c); | |
35 | cdb_findstart(c); | |
36 | c->fd = fd; | |
37 | ||
38 | if (fstat(fd,&st) == 0) | |
39 | if (st.st_size <= 0xffffffff) { | |
40 | x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0); | |
41 | if (x + 1) { | |
42 | c->size = st.st_size; | |
43 | c->map = x; | |
44 | } | |
45 | } | |
46 | } | |
47 | ||
48 | int cdb_read(struct cdb *c,char *buf,unsigned int len,uint32 pos) | |
49 | { | |
50 | if (c->map) { | |
51 | if ((pos > c->size) || (c->size - pos < len)) goto FORMAT; | |
52 | memcpy(buf,c->map + pos,len); | |
53 | } | |
54 | else { | |
55 | if (lseek(c->fd,pos,SEEK_SET) == -1) return -1; | |
56 | /* if (seek_set(c->fd,pos) == -1) return -1; */ | |
57 | while (len > 0) { | |
58 | int r; | |
59 | do | |
60 | r = read(c->fd,buf,len); | |
61 | while ((r == -1) && (errno == EINTR)); | |
62 | if (r == -1) return -1; | |
63 | if (r == 0) goto FORMAT; | |
64 | buf += r; | |
65 | len -= r; | |
66 | } | |
67 | } | |
68 | return 0; | |
69 | ||
70 | FORMAT: | |
71 | errno = EPROTO; | |
72 | return -1; | |
73 | } | |
74 | ||
75 | static int match(struct cdb *c,char *key,unsigned int len,uint32 pos) | |
76 | { | |
77 | char buf[32]; | |
78 | int n; | |
79 | ||
80 | while (len > 0) { | |
81 | n = sizeof buf; | |
82 | if (n > len) n = len; | |
83 | if (cdb_read(c,buf,n,pos) == -1) return -1; | |
84 | if (memcmp(buf,key,n)) return 0; | |
85 | pos += n; | |
86 | key += n; | |
87 | len -= n; | |
88 | } | |
89 | return 1; | |
90 | } | |
91 | ||
92 | int cdb_findnext(struct cdb *c,char *key,unsigned int len) | |
93 | { | |
94 | char buf[8]; | |
95 | uint32 pos; | |
96 | uint32 u; | |
97 | ||
98 | if (!c->loop) { | |
99 | u = cdb_hash(key,len); | |
100 | if (cdb_read(c,buf,8,(u << 3) & 2047) == -1) return -1; | |
101 | uint32_unpack(buf + 4,&c->hslots); | |
102 | if (!c->hslots) return 0; | |
103 | uint32_unpack(buf,&c->hpos); | |
104 | c->khash = u; | |
105 | u >>= 8; | |
106 | u %= c->hslots; | |
107 | u <<= 3; | |
108 | c->kpos = c->hpos + u; | |
109 | } | |
110 | ||
111 | while (c->loop < c->hslots) { | |
112 | if (cdb_read(c,buf,8,c->kpos) == -1) return -1; | |
113 | uint32_unpack(buf + 4,&pos); | |
114 | if (!pos) return 0; | |
115 | c->loop += 1; | |
116 | c->kpos += 8; | |
117 | if (c->kpos == c->hpos + (c->hslots << 3)) c->kpos = c->hpos; | |
118 | uint32_unpack(buf,&u); | |
119 | if (u == c->khash) { | |
120 | if (cdb_read(c,buf,8,pos) == -1) return -1; | |
121 | uint32_unpack(buf,&u); | |
122 | if (u == len) | |
123 | switch(match(c,key,len,pos + 8)) { | |
124 | case -1: | |
125 | return -1; | |
126 | case 1: | |
127 | uint32_unpack(buf + 4,&c->dlen); | |
128 | c->dpos = pos + 8 + len; | |
129 | return 1; | |
130 | } | |
131 | } | |
132 | } | |
133 | ||
134 | return 0; | |
135 | } | |
136 | ||
137 | int cdb_find(struct cdb *c,char *key,unsigned int len) | |
138 | { | |
139 | cdb_findstart(c); | |
140 | return cdb_findnext(c,key,len); | |
141 | } |