/* write mode */
void xdb_nput(xdb_t x, void *value, unsigned int vlen, const char *key, int len)
{
xrec_st rec;
if (x == NULL || x->fd < 0 || key == NULL || len > XDB_MAXKLEN)
return;
/* not found, return the poff(for write) */
_xdb_rec_find(x, key, len, &rec);
if (rec.value.len > 0 && vlen <= rec.value.len)
{
/* just replace */
if (vlen > 0)
{
lseek(x->fd, rec.value.off, SEEK_SET);
write(x->fd, value, vlen);
}
if (vlen < rec.value.len)
{
vlen += rec.me.len - rec.value.len;
lseek(x->fd, rec.poff + 4, SEEK_SET);
write(x->fd, &vlen, sizeof(vlen));
}
}
else if (vlen > 0)
{
/* insert for new data */
unsigned char buf[512];
xptr_st pnew;
pnew.off = x->fsize;
memset(buf, 0, sizeof(buf));
pnew.len = rec.me.len - rec.value.len;
if (pnew.len > 0)
{
_xdb_read_data(x, buf, rec.me.off, pnew.len);
}
else
{
buf[16] = len; // key len
strncpy(buf + 17, key, len);
pnew.len = 17 + len;
}
lseek(x->fd, pnew.off, SEEK_SET);
write(x->fd, buf, pnew.len);
write(x->fd, value, vlen);
pnew.len += vlen;
x->fsize += pnew.len;
/* update noff & vlen -> poff */
lseek(x->fd, rec.poff, SEEK_SET);
write(x->fd, &pnew, sizeof(pnew));
}
}
/* read mode (value require free by user) */
void *xdb_nget(xdb_t x, const char *key, int len, unsigned int *vlen)
{
xrec_st rec;
void *value = NULL;
if (x == NULL || key == NULL || len > XDB_MAXKLEN)
return NULL;
/* not found, return the poff(for write) */
_xdb_rec_find(x, key, len, &rec);
if (rec.value.len > 0)
{
/* auto append one byte with '\0' */
value = malloc(rec.value.len + 1);
if (vlen != NULL)
*vlen = rec.value.len;
_xdb_read_data(x, value, rec.value.off, rec.value.len);
}
return value;
}
