#include <stdlib.h>
#include <stdio.h>
#include <string.h>
-#include "misc.h"
#include "xmalloc.h"
#ifdef PSET
# include "pset.h"
#define SEGMENT_SIZE (1 << SEGMENT_SIZE_SHIFT)
#define DIRECTORY_SIZE_SHIFT 8
#define DIRECTORY_SIZE (1 << DIRECTORY_SIZE_SHIFT)
-#define MAX_LOAD_FACTOR 4
+#define MAX_LOAD_FACTOR 4
typedef struct element {
- struct element *chain;
+ struct element *chain; /* for chaining Elements */
MANGLEP (entry) entry;
} Element, *Segment;
struct SET {
- short p; /* Next bucket to be split */
- short maxp; /* upper bound on p during expansion */
- int nkey; /* current # keys */
- short nseg; /* current # segments */
+ unsigned p; /* Next bucket to be split */
+ unsigned maxp; /* upper bound on p during expansion */
+ unsigned nkey; /* current # keys */
+ unsigned nseg; /* current # segments */
Segment *dir[DIRECTORY_SIZE];
MANGLEP(cmp_fun) cmp; /* function comparing entries */
- int iter_i, iter_j;
+ unsigned iter_i, iter_j;
Element *iter_tail; /* non-NULL while iterating over elts */
#ifdef PSET
- Element *free_list;
+ Element *free_list; /* list of free Elements */
#endif
- struct obstack obst;
+ struct obstack obst; /* obstack for allocation all data */
#ifdef STATS
int naccess, ncollision, ndups;
int max_chain_len;
const char *MANGLEP(tag);
-static void
+void
MANGLEP(describe) (SET *table)
{
- int i, j, collide;
+ unsigned i, j, collide;
Element *ptr;
Segment *seg;
- printf ("p=%d maxp=%d nkey=%d nseg=%d\n",
+ printf ("p=%u maxp=%u nkey=%u nseg=%u\n",
table->p, table->maxp, table->nkey, table->nseg);
for (i = 0; i < table->nseg; i++) {
seg = table->dir[i];
while (ptr) {
if (collide) printf ("<%3d>", collide);
else printf ("table");
- printf ("[%d][%3d]: %u %p\n", i, j, ptr->entry.hash, ptr->entry.dptr);
+ printf ("[%d][%3d]: %u %p\n", i, j, ptr->entry.hash, (void *)ptr->entry.dptr);
ptr = ptr->chain;
collide++;
}
int i;
SET *table = xmalloc (sizeof (SET));
- /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
- assert (nslots >= 0);
- for (i = SEGMENT_SIZE; i < nslots; i <<= 1) assert (i < (i << 1));
- nslots = i >> SEGMENT_SIZE_SHIFT;
+ if (nslots > SEGMENT_SIZE * DIRECTORY_SIZE)
+ nslots = DIRECTORY_SIZE;
+ else {
+ assert (nslots >= 0);
+ /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
+ for (i = SEGMENT_SIZE; i < nslots; i <<= 1);
+ nslots = i >> SEGMENT_SIZE_SHIFT;
+ }
table->nseg = table->p = table->nkey = 0;
table->maxp = nslots << SEGMENT_SIZE_SHIFT;
table->dir[i] = (Segment *)obstack_alloc (&table->obst,
sizeof (Segment) * SEGMENT_SIZE);
- memset (table->dir[i], 0, sizeof (Segment) * SEGMENT_SIZE);
+ memset(table->dir[i], 0, sizeof (Segment) * SEGMENT_SIZE);
table->nseg++;
}
xfree (table);
}
+int
+MANGLEP(count) (SET *table)
+{
+ return table->nkey;
+}
+/*
+ * do one iteration step, return 1
+ * if still data in the set, 0 else
+ */
static INLINE int
iter_step (SET *table)
{
return 1;
}
-
+/*
+ * finds the first entry in the table
+ */
void *
MANGLEP(first) (SET *table)
{
return table->iter_tail->entry.dptr;
}
-
+/*
+ * returns next entry in the table
+ */
void *
MANGLEP(next) (SET *table)
{
- assert (table->iter_tail);
+ if (!table->iter_tail)
+ return NULL;
+
+ /* follow collision chain */
table->iter_tail = table->iter_tail->chain;
if (!table->iter_tail) {
+ /* go to next segment */
do {
if (!iter_step (table)) return NULL;
} while (!table->dir[table->iter_i][table->iter_j]);
void
MANGLEP(break) (SET *table)
{
- assert (table->iter_tail);
table->iter_tail = NULL;
}
-
+/*
+ * limit the hash value
+ */
static INLINE unsigned
Hash (SET *table, unsigned h)
{
unsigned address;
- address = h & (table->maxp - 1);
+ address = h & (table->maxp - 1); /* h % table->maxp */
if (address < (unsigned)table->p)
address = h & ((table->maxp << 1) - 1); /* h % (2*table->maxp) */
return address;
}
-
+/*
+ * returns non-zero if the number of elements in
+ * the set is greater then number of segments * MAX_LOAD_FACTOR
+ */
static INLINE int
loaded (SET *table)
{
> (table->nseg << SEGMENT_SIZE_SHIFT) * MAX_LOAD_FACTOR);
}
-
+/*
+ * expand the hash-table: the algorithm is split, so on every
+ * insert, only ONE segment is rehashed!
+ *
+ * table->p contains the current segment to split
+ * after all segments were split, table->p is set to zero and
+ * table->maxp is duplicated.
+ */
static void
expand_table (SET *table)
{
if (table->maxp + table->p < (DIRECTORY_SIZE << SEGMENT_SIZE_SHIFT)) {
/* Locate the bucket to be split */
- OldSegmentDir = table->p >> SEGMENT_SIZE_SHIFT;
- OldSegment = table->dir[OldSegmentDir];
+ OldSegmentDir = table->p >> SEGMENT_SIZE_SHIFT;
+ OldSegment = table->dir[OldSegmentDir];
OldSegmentIndex = table->p & (SEGMENT_SIZE-1);
/* Expand address space; if necessary create a new segment */
- NewAddress = table->maxp + table->p;
- NewSegmentDir = NewAddress >> SEGMENT_SIZE_SHIFT;
+ NewAddress = table->maxp + table->p;
+ NewSegmentDir = NewAddress >> SEGMENT_SIZE_SHIFT;
NewSegmentIndex = NewAddress & (SEGMENT_SIZE-1);
if (NewSegmentIndex == 0) {
table->dir[NewSegmentDir] =
(Segment *)obstack_alloc (&table->obst,
sizeof(Segment) * SEGMENT_SIZE);
+ memset(table->dir[NewSegmentDir], 0, sizeof(Segment) * SEGMENT_SIZE);
+ table->nseg++;
}
NewSegment = table->dir[NewSegmentDir];
table->maxp <<= 1; /* table->maxp *= 2 */
table->p = 0;
}
- table->nseg++;
/* Relocate records to the new bucket */
Previous = &OldSegment[OldSegmentIndex];
if (Hash (table, Current->entry.hash) == NewAddress) {
/* move to new chain */
*LastOfNew = Current;
- *Previous = Current->chain;
- LastOfNew = &Current->chain;
- Current = Current->chain;
+ *Previous = Current->chain;
+ LastOfNew = &Current->chain;
+ Current = Current->chain;
*LastOfNew = NULL;
} else {
/* leave on old chain */
/* Find collision chain */
h = Hash (table, hash);
- SegmentIndex = h & (SEGMENT_SIZE-1);
+ SegmentIndex = h & (SEGMENT_SIZE-1);
CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
assert (CurrentSegment != NULL);
q = CurrentSegment[SegmentIndex];
stat_chain_len (table, chain_len);
q = *p;
+
+ if (q == table->iter_tail) {
+ /* removing current element */
+ table->iter_tail = q->chain;
+ if (!table->iter_tail) {
+ /* go to next segment */
+ do {
+ if (!iter_step (table))
+ break;
+ } while (!table->dir[table->iter_i][table->iter_j]);
+ table->iter_tail = table->dir[table->iter_i][table->iter_j];
+ }
+ }
+
*p = (*p)->chain;
q->chain = table->free_list;
table->free_list = q;
+ --table->nkey;
return q->entry.dptr;
}