/* recursive to search the matched record */
static void _xdb_rec_get(xdb_t x, xrec_t rec, const char *key, int len)
{
unsigned char buf[XDB_MAXKLEN + 2]; // greater than: 255
int cmp;
if (rec->me.len == 0)
return;
// [left][right] = 16\0
_xdb_read_data(x, buf, rec->me.off + 16, len + 1);
cmp = memcmp(key, buf+1, len);
if (!cmp)
cmp = len - buf[0];
if (cmp > 0)
{
// right
rec->poff = rec->me.off + sizeof(xptr_st);
_xdb_read_data(x, &rec->me, rec->me.off + sizeof(xptr_st), sizeof(xptr_st));
_xdb_rec_get(x, rec, key, len);
}
else if (cmp < 0)
{
// left
rec->poff = rec->me.off;
_xdb_read_data(x, &rec->me, rec->me.off, sizeof(xptr_st));
_xdb_rec_get(x, rec, key, len);
}
else
{
// found!
rec->value.off = rec->me.off + 17 + len;
rec->value.len = rec->me.len - 17 - len;
}
}
static void _xdb_count_nodes(xdb_t x, xptr_t ptr, int *count)
{
int off;
if (ptr->len == 0)
return;
*count += 1;
off = ptr->off;
/* left & right */
_xdb_read_data(x, ptr, off, sizeof(xptr_st));
_xdb_count_nodes(x, ptr, count);
_xdb_read_data(x, ptr, off + sizeof(xptr_st), sizeof(xptr_st));
_xdb_count_nodes(x, ptr, count);
}
static void _xdb_load_nodes(xdb_t x, xptr_t ptr, xcmper_st *nodes, int *count)
{
int i;
unsigned char buf[XDB_MAXKLEN + 18];
if (ptr->len == 0)
return;
i = sizeof(buf)-1;
if (i > (int)ptr->len)
i = ptr->len;
_xdb_read_data(x, buf, ptr->off, i);
i = *count;
nodes[i].ptr.off = ptr->off;
nodes[i].ptr.len = ptr->len;
nodes[i].key = (char *) _mem_ndup(buf + 17, buf[16]);
*count = i+1;
/* left & right */
memcpy(ptr, buf, sizeof(xptr_st));
_xdb_load_nodes(x, ptr, nodes, count);
memcpy(ptr, buf + sizeof(xptr_st), sizeof(xptr_st));
_xdb_load_nodes(x, ptr, nodes, count);
}
static void _xdb_draw_node(xdb_t x, xptr_t ptr, struct draw_arg *arg, int depth, char *icon1)
{
char *icon2;
icon2 = malloc(strlen(icon1) + 4);
strcpy(icon2, icon1);
// output the flag & icon
if (arg->flag == 'T')
printf("(Ｔ) ");
else
{
printf("%s", icon2);
if (arg->flag == 'L')
{
strcat(icon2, " ┃");
printf(" ┟(Ｌ) ");
}
else
{
strcat(icon2, " ");
printf(" └(Ｒ) ");
}
}
// draw the node data
if (ptr->len == 0)
printf("<NULL>\n");
else
{
unsigned char buf[XDB_MAXKLEN + 18]; // greater than 18 = sizeof(xptr_st)*2+1
int vlen, voff;
vlen = sizeof(buf) - 1;
if (vlen > ptr->len)
vlen = ptr->len;
_xdb_read_data(x, buf, ptr->off, vlen);
vlen = ptr->len - buf[16] - 17;
voff = ptr->off + buf[16] + 17;
printf("%.*s (vlen=%d, voff=%d)\n", buf[16], buf+17, vlen, voff);
arg->count++;
depth++;
if (depth > arg->depth)
arg->depth = depth;
// draw the left & right;
arg->flag = 'L';
memcpy(ptr, buf, sizeof(xptr_st));
_xdb_draw_node(x, ptr, arg, depth, icon2);
arg->flag = 'R';
memcpy(ptr, buf + sizeof(xptr_st), sizeof(xptr_st));
_xdb_draw_node(x, ptr, arg, depth, icon2);
}
free(icon2);
}
/* 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));
}
}
static xrec_t _xdb_rec_find(xdb_t x, const char *key, int len, xrec_t rec)
{
int i;
if (rec == NULL)
rec = (xrec_t) malloc(sizeof(xrec_st));
memset(rec, 0, sizeof(xrec_st));
i = (x->prime > 1 ? _xdb_hasher(x, key, len) : 0);
rec->poff = i * sizeof(xptr_st) + sizeof(struct xdb_header);
_xdb_read_data(x, &rec->me, rec->poff, sizeof(xptr_st));
_xdb_rec_get(x, rec, key, len);
return rec;
}
/* 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;
}
void xdb_draw(xdb_t x)
{
int i;
struct draw_arg arg;
xptr_st ptr;
if (!x) return;
xdb_version(x);
for (i = 0; i < x->prime; i++)
{
arg.depth = 0;
arg.count = 0;
arg.flag = 'T';
_xdb_read_data(x, &ptr, i * sizeof(xptr_st) + sizeof(struct xdb_header), sizeof(xptr_st));
_xdb_draw_node(x, &ptr, &arg, 0, "");
printf("-----------------------------------------\n");
printf("Tree(xdb) [%d] max_depth: %d nodes_num: %d\n", i, arg.depth, arg.count);
}
}
