netcdf-c/libsrc/nc_hashmap.c

399 lines
8.6 KiB
C

#include "nc3internal.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
/* this should be prime */
#define TABLE_STARTSIZE 1021
#define ACTIVE 1
#define MAX(a,b) ((a) > (b) ? (a) : (b))
extern uint32_t hash_fast(const void *key, size_t length);
static int isPrime(unsigned long val)
{
int i;
for (i = 9; i--;)
{
#ifdef HAVE_RANDOM
unsigned long a = ((unsigned long)random() % (val-4)) + 2;
#else
unsigned long a = ((unsigned long)rand() % (val - 4)) + 2;
#endif
unsigned long p = 1;
unsigned long exp = val-1;
while (exp)
{
if (exp & 1)
p = (p*a)%val;
a = (a*a)%val;
exp >>= 1;
}
if (p != 1)
return 0;
}
return 1;
}
static unsigned long findPrimeGreaterThan(unsigned long val)
{
if (val & 1)
val+=2;
else
val++;
while (!isPrime(val))
val+=2;
return val;
}
static void rehashDim(const NC_dimarray* ncap)
{
NC_hashmap* hm = ncap->hashmap;
unsigned long size = hm->size;
unsigned long count = hm->count;
hEntry* table = hm->table;
hm->size = findPrimeGreaterThan(size<<1);
hm->table = (hEntry*)calloc(sizeof(hEntry), hm->size);
hm->count = 0;
while(size > 0) {
--size;
if (table[size].flags == ACTIVE) {
NC_dim *elem = ncap->value[table[size].data-1];
NC_hashmapAddDim(ncap, table[size].data-1, elem->name->cp);
assert(NC_hashmapGetDim(ncap, elem->name->cp) == table[size].data-1);
}
}
free(table);
assert(count == hm->count);
}
static void rehashVar(const NC_vararray* ncap)
{
NC_hashmap* hm = ncap->hashmap;
unsigned long size = hm->size;
unsigned long count = hm->count;
hEntry* table = hm->table;
hm->size = findPrimeGreaterThan(size<<1);
hm->table = (hEntry*)calloc(sizeof(hEntry), (size_t)hm->size);
hm->count = 0;
while(size > 0) {
--size;
if (table[size].flags == ACTIVE) {
NC_var *elem = ncap->value[table[size].data-1];
NC_hashmapAddVar(ncap, table[size].data-1, elem->name->cp);
assert(NC_hashmapGetVar(ncap, elem->name->cp) == table[size].data-1);
}
}
free(table);
assert(count == hm->count);
}
NC_hashmap* NC_hashmapCreate(unsigned long startsize)
{
NC_hashmap* hm = (NC_hashmap*)malloc(sizeof(NC_hashmap));
if (!startsize)
startsize = TABLE_STARTSIZE;
else {
startsize *= 4;
startsize /= 3;
startsize = findPrimeGreaterThan(startsize-2);
}
hm->table = (hEntry*)calloc(sizeof(hEntry), (size_t)startsize);
hm->size = startsize;
hm->count = 0;
return hm;
}
void NC_hashmapAddDim(const NC_dimarray* ncap, long data, const char *name)
{
unsigned long key = hash_fast(name, strlen(name));
NC_hashmap* hash = ncap->hashmap;
if (hash->size*3/4 <= hash->count) {
rehashDim(ncap);
}
do
{
unsigned long i;
unsigned long index = key % hash->size;
unsigned long step = (key % MAX(1,(hash->size-2))) + 1;
for (i = 0; i < hash->size; i++)
{
if (hash->table[index].flags & ACTIVE)
{
hEntry entry = hash->table[index];
if (entry.key == key &&
strncmp(name, ncap->value[entry.data-1]->name->cp,
ncap->value[entry.data-1]->name->nchars) == 0)
{
hash->table[index].data = data+1;
return;
}
}
else
{
hash->table[index].flags |= ACTIVE;
hash->table[index].data = data+1;
hash->table[index].key = key;
++hash->count;
return;
}
index = (index + step) % hash->size;
}
/* it should not be possible that we EVER come this far, but unfortunately
not every generated prime number is prime (Carmichael numbers...) */
rehashDim(ncap);
}
while (1);
}
void NC_hashmapAddVar(const NC_vararray* ncap, long data, const char *name)
{
unsigned long key = hash_fast(name, strlen(name));
NC_hashmap* hash = ncap->hashmap;
if (hash->size*3/4 <= hash->count) {
rehashVar(ncap);
}
do
{
unsigned long i;
unsigned long index = key % hash->size;
unsigned long step = (key % MAX(1,(hash->size-2))) + 1;
for (i = 0; i < hash->size; i++)
{
if (hash->table[index].flags & ACTIVE)
{
hEntry entry = hash->table[index];
if (entry.key == key &&
strncmp(name, ncap->value[entry.data-1]->name->cp,
ncap->value[entry.data-1]->name->nchars) == 0)
{
hash->table[index].data = data+1;
return;
}
}
else
{
hash->table[index].flags |= ACTIVE;
hash->table[index].data = data+1;
hash->table[index].key = key;
++hash->count;
return;
}
index = (index + step) % hash->size;
}
/* it should not be possible that we EVER come this far, but unfortunately
not every generated prime number is prime (Carmichael numbers...) */
rehashVar(ncap);
}
while (1);
}
long NC_hashmapRemoveDim(const NC_dimarray* ncap, const char *name)
{
unsigned long i;
unsigned long key = hash_fast(name, strlen(name));
NC_hashmap* hash = ncap->hashmap;
unsigned long index = key % hash->size;
unsigned long step = (key % (hash->size-2)) + 1;
for (i = 0; i < hash->size; i++)
{
if (hash->table[index].data > 0)
{
hEntry entry = hash->table[index];
if (entry.key == key &&
strncmp(name, ncap->value[entry.data-1]->name->cp,
ncap->value[entry.data-1]->name->nchars) == 0)
{
if (hash->table[index].flags & ACTIVE)
{
hash->table[index].flags &= ~ACTIVE;
--hash->count;
return hash->table[index].data-1;
}
else /* in, but not active (i.e. deleted) */
return -1;
}
}
else /* found an empty place (can't be in) */
return -1;
index = (index + step) % hash->size;
}
/* everything searched through, but not in */
return -1;
}
long NC_hashmapRemoveVar(const NC_vararray* ncap, const char *name)
{
unsigned long i;
unsigned long key = hash_fast(name, strlen(name));
NC_hashmap* hash = ncap->hashmap;
unsigned long index = key % hash->size;
unsigned long step = (key % (hash->size-2)) + 1;
for (i = 0; i < hash->size; i++)
{
if (hash->table[index].data > 0)
{
hEntry entry = hash->table[index];
if (entry.key == key &&
strncmp(name, ncap->value[entry.data-1]->name->cp,
ncap->value[entry.data-1]->name->nchars) == 0)
{
if (hash->table[index].flags & ACTIVE)
{
hash->table[index].flags &= ~ACTIVE;
--hash->count;
return hash->table[index].data-1;
}
else /* in, but not active (i.e. deleted) */
return -1;
}
}
else /* found an empty place (can't be in) */
return -1;
index = (index + step) % hash->size;
}
/* everything searched through, but not in */
return -1;
}
long NC_hashmapGetDim(const NC_dimarray* ncap, const char *name)
{
NC_hashmap* hash = ncap->hashmap;
if (hash->count)
{
unsigned long key = hash_fast(name, strlen(name));
NC_hashmap* hash = ncap->hashmap;
unsigned long i;
unsigned long index = key % hash->size;
unsigned long step = (key % (hash->size-2)) + 1;
for (i = 0; i < hash->size; i++)
{
hEntry entry = hash->table[index];
if (entry.key == key &&
strncmp(name, ncap->value[entry.data-1]->name->cp,
ncap->value[entry.data-1]->name->nchars) == 0)
{
if (entry.flags & ACTIVE)
return entry.data-1;
break;
}
else
if (!(entry.flags & ACTIVE))
break;
index = (index + step) % hash->size;
}
}
return -1;
}
long NC_hashmapGetVar(const NC_vararray* ncap, const char *name)
{
NC_hashmap* hash = ncap->hashmap;
if (hash->count)
{
unsigned long key = hash_fast(name, strlen(name));
NC_hashmap* hash = ncap->hashmap;
unsigned long i;
unsigned long index = key % hash->size;
unsigned long step = (key % (hash->size-2)) + 1;
for (i = 0; i < hash->size; i++)
{
hEntry entry = hash->table[index];
if (entry.key == key &&
strncmp(name, ncap->value[entry.data-1]->name->cp,
ncap->value[entry.data-1]->name->nchars) == 0)
{
if (entry.flags & ACTIVE)
return entry.data-1;
break;
}
else
if (!(entry.flags & ACTIVE))
break;
index = (index + step) % hash->size;
}
}
return -1;
}
unsigned long NC_hashmapCount(NC_hashmap* hash)
{
return hash->count;
}
void NC_hashmapDelete(NC_hashmap* hash)
{
if (hash) {
free(hash->table);
free(hash);
}
}
void
NC_hashmap_verify(NC_hashmap* hash, NC_dim** dims)
{
unsigned long i;
if(hash->count == 0) {
fprintf(stderr,"<empty>\n");
goto done;
}
for(i=0;i<hash->size;i++) {
hEntry* e = &hash->table[i];
if(e->flags == ACTIVE) {
fprintf(stderr,"[%d] key=%lu data=%ld",(int)i,e->key,e->data-1);
if(dims != NULL) {
fprintf(stderr," name=%s",dims[e->data-1]->name->cp);
}
fprintf(stderr,"\n");
}
}
done:
fflush(stderr);
}