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136 lines
2.6 KiB
136 lines
2.6 KiB
/* Public domain. */
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#include <stdint.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include "readwrite.h"
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#include "error.h"
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#include "seek.h"
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#include "byte.h"
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#include "cdb.h"
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void cdb_free(struct cdb *c)
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{
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if (c->map) {
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munmap(c->map,c->size);
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c->map = 0;
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}
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}
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void cdb_findstart(struct cdb *c)
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{
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c->loop = 0;
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}
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void cdb_init(struct cdb *c,int fd)
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{
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struct stat st;
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char *x;
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cdb_free(c);
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cdb_findstart(c);
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c->fd = fd;
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if (fstat(fd,&st) == 0)
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if (st.st_size <= 0xffffffff) {
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x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0);
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if (x + 1) {
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c->size = (uint32_t)st.st_size;
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c->map = x;
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}
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}
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}
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int cdb_read(struct cdb *c,char *buf,unsigned int len,uint32 pos)
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{
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if (c->map) {
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if ((pos > c->size) || (c->size - pos < len)) goto FORMAT;
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byte_copy(buf,len,c->map + pos);
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}
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else {
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if (seek_set(c->fd,pos) == -1) return -1;
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while (len > 0) {
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int32_t r;
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do
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r = (int32_t)read(c->fd,buf,len);
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while ((r == -1) && (errno == error_intr));
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if (r == -1) return -1;
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if (r == 0) goto FORMAT;
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buf += r;
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len -= r;
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}
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}
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return 0;
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FORMAT:
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errno = error_proto;
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return -1;
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}
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static int match(struct cdb *c,char *key,unsigned int len,uint32 pos)
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{
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char buf[32];
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int n;
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while (len > 0) {
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n = sizeof buf;
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if (n > len) n = len;
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if (cdb_read(c,buf,n,pos) == -1) return -1;
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if (byte_diff(buf,n,key)) return 0;
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pos += n;
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key += n;
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len -= n;
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}
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return 1;
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}
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int cdb_findnext(struct cdb *c,char *key,unsigned int len)
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{
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char buf[8];
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uint32 pos;
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uint32 u;
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if (!c->loop) {
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u = cdb_hash(key,len);
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if (cdb_read(c,buf,8,(u << 3) & 2047) == -1) return -1;
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uint32_unpack(buf + 4,&c->hslots);
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if (!c->hslots) return 0;
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uint32_unpack(buf,&c->hpos);
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c->khash = u;
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u >>= 8;
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u %= c->hslots;
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u <<= 3;
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c->kpos = c->hpos + u;
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}
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while (c->loop < c->hslots) {
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if (cdb_read(c,buf,8,c->kpos) == -1) return -1;
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uint32_unpack(buf + 4,&pos);
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if (!pos) return 0;
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c->loop += 1;
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c->kpos += 8;
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if (c->kpos == c->hpos + (c->hslots << 3)) c->kpos = c->hpos;
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uint32_unpack(buf,&u);
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if (u == c->khash) {
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if (cdb_read(c,buf,8,pos) == -1) return -1;
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uint32_unpack(buf,&u);
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if (u == len)
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switch(match(c,key,len,pos + 8)) {
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case -1:
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return -1;
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case 1:
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uint32_unpack(buf + 4,&c->dlen);
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c->dpos = pos + 8 + len;
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return 1;
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}
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}
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}
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return 0;
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}
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int cdb_find(struct cdb *c,char *key,unsigned int len)
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{
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cdb_findstart(c);
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return cdb_findnext(c,key,len);
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}
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