Commit | Line | Data |
---|---|---|
dc0d77d7 CE |
1 | /* Public domain. */ |
2 | ||
3 | #include <sys/types.h> | |
4 | #include <sys/stat.h> | |
5 | #include <sys/mman.h> | |
6 | #include <unistd.h> | |
7 | #include "error.h" | |
8 | #include "seek.h" | |
9 | #include "byte.h" | |
10 | #include "cdb.h" | |
11 | ||
12 | void cdb_free(struct cdb *c) | |
13 | { | |
14 | if (c->map) { | |
15 | munmap(c->map,c->size); | |
16 | c->map = 0; | |
17 | } | |
18 | } | |
19 | ||
20 | void cdb_findstart(struct cdb *c) | |
21 | { | |
22 | c->loop = 0; | |
23 | } | |
24 | ||
25 | void cdb_init(struct cdb *c,int fd) | |
26 | { | |
27 | struct stat st; | |
28 | char *x; | |
29 | ||
30 | cdb_free(c); | |
31 | cdb_findstart(c); | |
32 | c->fd = fd; | |
33 | ||
34 | if (fstat(fd,&st) == 0) | |
35 | if (st.st_size <= 0xffffffff) { | |
36 | x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0); | |
37 | if (x + 1) { | |
38 | c->size = st.st_size; | |
39 | c->map = x; | |
40 | } | |
41 | } | |
42 | } | |
43 | ||
44 | int cdb_read(struct cdb *c,char *buf,unsigned int len,uint32 pos) | |
45 | { | |
46 | if (c->map) { | |
47 | if ((pos > c->size) || (c->size - pos < len)) goto FORMAT; | |
48 | byte_copy(buf,len,c->map + pos); | |
49 | } | |
50 | else { | |
51 | if (seek_set(c->fd,pos) == -1) return -1; | |
52 | while (len > 0) { | |
53 | int r; | |
54 | do | |
55 | r = read(c->fd,buf,len); | |
56 | while ((r == -1) && (errno == error_intr)); | |
57 | if (r == -1) return -1; | |
58 | if (r == 0) goto FORMAT; | |
59 | buf += r; | |
60 | len -= r; | |
61 | } | |
62 | } | |
63 | return 0; | |
64 | ||
65 | FORMAT: | |
66 | errno = error_proto; | |
67 | return -1; | |
68 | } | |
69 | ||
70 | static int match(struct cdb *c,const char *key,unsigned int len,uint32 pos) | |
71 | { | |
72 | char buf[32]; | |
73 | int n; | |
74 | ||
75 | while (len > 0) { | |
76 | n = sizeof buf; | |
77 | if (n > len) n = len; | |
78 | if (cdb_read(c,buf,n,pos) == -1) return -1; | |
79 | if (byte_diff(buf,n,key)) return 0; | |
80 | pos += n; | |
81 | key += n; | |
82 | len -= n; | |
83 | } | |
84 | return 1; | |
85 | } | |
86 | ||
87 | int cdb_findnext(struct cdb *c,const char *key,unsigned int len) | |
88 | { | |
89 | char buf[8]; | |
90 | uint32 pos; | |
91 | uint32 u; | |
92 | ||
93 | if (!c->loop) { | |
94 | u = cdb_hash(key,len); | |
95 | if (cdb_read(c,buf,8,(u << 3) & 2047) == -1) return -1; | |
96 | uint32_unpack(buf + 4,&c->hslots); | |
97 | if (!c->hslots) return 0; | |
98 | uint32_unpack(buf,&c->hpos); | |
99 | c->khash = u; | |
100 | u >>= 8; | |
101 | u %= c->hslots; | |
102 | u <<= 3; | |
103 | c->kpos = c->hpos + u; | |
104 | } | |
105 | ||
106 | while (c->loop < c->hslots) { | |
107 | if (cdb_read(c,buf,8,c->kpos) == -1) return -1; | |
108 | uint32_unpack(buf + 4,&pos); | |
109 | if (!pos) return 0; | |
110 | c->loop += 1; | |
111 | c->kpos += 8; | |
112 | if (c->kpos == c->hpos + (c->hslots << 3)) c->kpos = c->hpos; | |
113 | uint32_unpack(buf,&u); | |
114 | if (u == c->khash) { | |
115 | if (cdb_read(c,buf,8,pos) == -1) return -1; | |
116 | uint32_unpack(buf,&u); | |
117 | if (u == len) | |
118 | switch(match(c,key,len,pos + 8)) { | |
119 | case -1: | |
120 | return -1; | |
121 | case 1: | |
122 | uint32_unpack(buf + 4,&c->dlen); | |
123 | c->dpos = pos + 8 + len; | |
124 | return 1; | |
125 | } | |
126 | } | |
127 | } | |
128 | ||
129 | return 0; | |
130 | } | |
131 | ||
132 | int cdb_find(struct cdb *c,const char *key,unsigned int len) | |
133 | { | |
134 | cdb_findstart(c); | |
135 | return cdb_findnext(c,key,len); | |
136 | } |