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DEFINITIONS
This source file includes following definitions.
- new_size
- stat_col
- st_init_table_with_size
- st_init_table
- st_init_numtable
- st_init_numtable_with_size
- st_init_strtable
- st_init_strtable_with_size
- st_free_table
- st_lookup
- st_insert
- st_add_direct
- rehash
- st_copy
- st_delete
- st_delete_safe
- delete_never
- st_cleanup_safe
- st_foreach
- strhash
- numcmp
- numhash
/* This is a public domain general purpose hash table package written by Peter Moore @ UCB. */
/* static char sccsid[] = "@(#) st.c 5.1 89/12/14 Crucible"; */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <malloc.h>
#endif
#include "regint.h"
#include "st.h"
typedef struct st_table_entry st_table_entry;
struct st_table_entry {
unsigned int hash;
st_data_t key;
st_data_t record;
st_table_entry *next;
};
#define ST_DEFAULT_MAX_DENSITY 5
#define ST_DEFAULT_INIT_TABLE_SIZE 11
/*
* DEFAULT_MAX_DENSITY is the default for the largest we allow the
* average number of items per bin before increasing the number of
* bins
*
* DEFAULT_INIT_TABLE_SIZE is the default for the number of bins
* allocated initially
*
*/
static int numcmp(long, long);
static int numhash(long);
static struct st_hash_type type_numhash = {
numcmp,
numhash,
};
/* extern int strcmp(const char *, const char *); */
static int strhash(const char *);
static struct st_hash_type type_strhash = {
strcmp,
strhash,
};
static void rehash(st_table *);
#define alloc(type) (type*)xmalloc((unsigned)sizeof(type))
#define Calloc(n,s) (char*)xcalloc((n),(s))
#define EQUAL(table,x,y) ((x)==(y) || (*table->type->compare)((x),(y)) == 0)
#define do_hash(key,table) (unsigned int)(*(table)->type->hash)((key))
#define do_hash_bin(key,table) (do_hash(key, table)%(table)->num_bins)
/*
* MINSIZE is the minimum size of a dictionary.
*/
#define MINSIZE 8
/*
Table of prime numbers 2^n+a, 2<=n<=30.
*/
static const long primes[] = {
8 + 3,
16 + 3,
32 + 5,
64 + 3,
128 + 3,
256 + 27,
512 + 9,
1024 + 9,
2048 + 5,
4096 + 3,
8192 + 27,
16384 + 43,
32768 + 3,
65536 + 45,
131072 + 29,
262144 + 3,
524288 + 21,
1048576 + 7,
2097152 + 17,
4194304 + 15,
8388608 + 9,
16777216 + 43,
33554432 + 35,
67108864 + 15,
134217728 + 29,
268435456 + 3,
536870912 + 11,
1073741824 + 85,
0
};
static int
new_size(size)
int size;
{
int i;
#if 0
for (i=3; i<31; i++) {
if ((1<<i) > size) return 1<<i;
}
return -1;
#else
int newsize;
for (i = 0, newsize = MINSIZE;
i < (int )(sizeof(primes)/sizeof(primes[0]));
i++, newsize <<= 1)
{
if (newsize > size) return primes[i];
}
/* Ran out of polynomials */
return -1; /* should raise exception */
#endif
}
#ifdef HASH_LOG
static int collision = 0;
static int init_st = 0;
static void
stat_col()
{
FILE *f = fopen("/tmp/col", "w");
fprintf(f, "collision: %d\n", collision);
fclose(f);
}
#endif
st_table*
st_init_table_with_size(type, size)
struct st_hash_type *type;
int size;
{
st_table *tbl;
#ifdef HASH_LOG
if (init_st == 0) {
init_st = 1;
atexit(stat_col);
}
#endif
size = new_size(size); /* round up to prime number */
tbl = alloc(st_table);
tbl->type = type;
tbl->num_entries = 0;
tbl->num_bins = size;
tbl->bins = (st_table_entry **)Calloc(size, sizeof(st_table_entry*));
return tbl;
}
st_table*
st_init_table(type)
struct st_hash_type *type;
{
return st_init_table_with_size(type, 0);
}
st_table*
st_init_numtable(void)
{
return st_init_table(&type_numhash);
}
st_table*
st_init_numtable_with_size(size)
int size;
{
return st_init_table_with_size(&type_numhash, size);
}
st_table*
st_init_strtable(void)
{
return st_init_table(&type_strhash);
}
st_table*
st_init_strtable_with_size(size)
int size;
{
return st_init_table_with_size(&type_strhash, size);
}
void
st_free_table(table)
st_table *table;
{
register st_table_entry *ptr, *next;
int i;
for(i = 0; i < table->num_bins; i++) {
ptr = table->bins[i];
while (ptr != 0) {
next = ptr->next;
free(ptr);
ptr = next;
}
}
free(table->bins);
free(table);
}
#define PTR_NOT_EQUAL(table, ptr, hash_val, key) \
((ptr) != 0 && (ptr->hash != (hash_val) || !EQUAL((table), (key), (ptr)->key)))
#ifdef HASH_LOG
#define COLLISION collision++
#else
#define COLLISION
#endif
#define FIND_ENTRY(table, ptr, hash_val, bin_pos) do {\
bin_pos = hash_val%(table)->num_bins;\
ptr = (table)->bins[bin_pos];\
if (PTR_NOT_EQUAL(table, ptr, hash_val, key)) {\
COLLISION;\
while (PTR_NOT_EQUAL(table, ptr->next, hash_val, key)) {\
ptr = ptr->next;\
}\
ptr = ptr->next;\
}\
} while (0)
int
st_lookup(table, key, value)
st_table *table;
register st_data_t key;
st_data_t *value;
{
unsigned int hash_val, bin_pos;
register st_table_entry *ptr;
hash_val = do_hash(key, table);
FIND_ENTRY(table, ptr, hash_val, bin_pos);
if (ptr == 0) {
return 0;
}
else {
if (value != 0) *value = ptr->record;
return 1;
}
}
#define ADD_DIRECT(table, key, value, hash_val, bin_pos)\
do {\
st_table_entry *entry;\
if (table->num_entries/(table->num_bins) > ST_DEFAULT_MAX_DENSITY) {\
rehash(table);\
bin_pos = hash_val % table->num_bins;\
}\
\
entry = alloc(st_table_entry);\
\
entry->hash = hash_val;\
entry->key = key;\
entry->record = value;\
entry->next = table->bins[bin_pos];\
table->bins[bin_pos] = entry;\
table->num_entries++;\
} while (0)
int
st_insert(table, key, value)
register st_table *table;
register st_data_t key;
st_data_t value;
{
unsigned int hash_val, bin_pos;
register st_table_entry *ptr;
hash_val = do_hash(key, table);
FIND_ENTRY(table, ptr, hash_val, bin_pos);
if (ptr == 0) {
ADD_DIRECT(table, key, value, hash_val, bin_pos);
return 0;
}
else {
ptr->record = value;
return 1;
}
}
void
st_add_direct(table, key, value)
st_table *table;
st_data_t key;
st_data_t value;
{
unsigned int hash_val, bin_pos;
hash_val = do_hash(key, table);
bin_pos = hash_val % table->num_bins;
ADD_DIRECT(table, key, value, hash_val, bin_pos);
}
static void
rehash(table)
register st_table *table;
{
register st_table_entry *ptr, *next, **new_bins;
int i, old_num_bins = table->num_bins, new_num_bins;
unsigned int hash_val;
new_num_bins = new_size(old_num_bins+1);
new_bins = (st_table_entry**)Calloc(new_num_bins, sizeof(st_table_entry*));
for(i = 0; i < old_num_bins; i++) {
ptr = table->bins[i];
while (ptr != 0) {
next = ptr->next;
hash_val = ptr->hash % new_num_bins;
ptr->next = new_bins[hash_val];
new_bins[hash_val] = ptr;
ptr = next;
}
}
free(table->bins);
table->num_bins = new_num_bins;
table->bins = new_bins;
}
st_table*
st_copy(old_table)
st_table *old_table;
{
st_table *new_table;
st_table_entry *ptr, *entry;
int i, num_bins = old_table->num_bins;
new_table = alloc(st_table);
if (new_table == 0) {
return 0;
}
*new_table = *old_table;
new_table->bins = (st_table_entry**)
Calloc((unsigned)num_bins, sizeof(st_table_entry*));
if (new_table->bins == 0) {
free(new_table);
return 0;
}
for(i = 0; i < num_bins; i++) {
new_table->bins[i] = 0;
ptr = old_table->bins[i];
while (ptr != 0) {
entry = alloc(st_table_entry);
if (entry == 0) {
free(new_table->bins);
free(new_table);
return 0;
}
*entry = *ptr;
entry->next = new_table->bins[i];
new_table->bins[i] = entry;
ptr = ptr->next;
}
}
return new_table;
}
int
st_delete(table, key, value)
register st_table *table;
register st_data_t *key;
st_data_t *value;
{
unsigned int hash_val;
st_table_entry *tmp;
register st_table_entry *ptr;
hash_val = do_hash_bin(*key, table);
ptr = table->bins[hash_val];
if (ptr == 0) {
if (value != 0) *value = 0;
return 0;
}
if (EQUAL(table, *key, ptr->key)) {
table->bins[hash_val] = ptr->next;
table->num_entries--;
if (value != 0) *value = ptr->record;
*key = ptr->key;
free(ptr);
return 1;
}
for(; ptr->next != 0; ptr = ptr->next) {
if (EQUAL(table, ptr->next->key, *key)) {
tmp = ptr->next;
ptr->next = ptr->next->next;
table->num_entries--;
if (value != 0) *value = tmp->record;
*key = tmp->key;
free(tmp);
return 1;
}
}
return 0;
}
int
st_delete_safe(table, key, value, never)
register st_table *table;
register st_data_t *key;
st_data_t *value;
st_data_t never;
{
unsigned int hash_val;
register st_table_entry *ptr;
hash_val = do_hash_bin(*key, table);
ptr = table->bins[hash_val];
if (ptr == 0) {
if (value != 0) *value = 0;
return 0;
}
for(; ptr != 0; ptr = ptr->next) {
if ((ptr->key != never) && EQUAL(table, ptr->key, *key)) {
table->num_entries--;
*key = ptr->key;
if (value != 0) *value = ptr->record;
ptr->key = ptr->record = never;
return 1;
}
}
return 0;
}
static int
#if defined(__GNUC__)
delete_never(st_data_t key __attribute__ ((unused)), st_data_t value,
st_data_t never)
#else
delete_never(key, value, never)
st_data_t key, value, never;
#endif
{
if (value == never) return ST_DELETE;
return ST_CONTINUE;
}
void
st_cleanup_safe(table, never)
st_table *table;
st_data_t never;
{
int num_entries = table->num_entries;
st_foreach(table, delete_never, never);
table->num_entries = num_entries;
}
int
st_foreach(table, func, arg)
st_table *table;
int (*func)();
st_data_t arg;
{
st_table_entry *ptr, *last, *tmp;
enum st_retval retval;
int i;
for(i = 0; i < table->num_bins; i++) {
last = 0;
for(ptr = table->bins[i]; ptr != 0;) {
retval = (*func)(ptr->key, ptr->record, arg);
switch (retval) {
case ST_CHECK: /* check if hash is modified during iteration */
tmp = 0;
if (i < table->num_bins) {
for (tmp = table->bins[i]; tmp; tmp=tmp->next) {
if (tmp == ptr) break;
}
}
if (!tmp) {
/* call func with error notice */
return 1;
}
/* fall through */
case ST_CONTINUE:
last = ptr;
ptr = ptr->next;
break;
case ST_STOP:
return 0;
case ST_DELETE:
tmp = ptr;
if (last == 0) {
table->bins[i] = ptr->next;
}
else {
last->next = ptr->next;
}
ptr = ptr->next;
free(tmp);
table->num_entries--;
}
}
}
return 0;
}
static int
strhash(string)
register const char *string;
{
register int c;
#ifdef HASH_ELFHASH
register unsigned int h = 0, g;
while ((c = *string++) != '\0') {
h = ( h << 4 ) + c;
if ( g = h & 0xF0000000 )
h ^= g >> 24;
h &= ~g;
}
return h;
#elif HASH_PERL
register int val = 0;
while ((c = *string++) != '\0') {
val += c;
val += (val << 10);
val ^= (val >> 6);
}
val += (val << 3);
val ^= (val >> 11);
return val + (val << 15);
#else
register int val = 0;
while ((c = *string++) != '\0') {
val = val*997 + c;
}
return val + (val>>5);
#endif
}
static int
numcmp(x, y)
long x, y;
{
return x != y;
}
static int
numhash(n)
long n;
{
return n;
}