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/* This is a general purpose hash table package written by Peter Moore @ UCB. */
static char sccsid[] = "@(#) st.c 5.1 89/12/14 Crucible";
#include "config.h"
#include <stdio.h>
#include "st.h"
#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();
static int numhash();
static struct st_hash_type type_numhash = {
numcmp,
numhash,
};
extern int strcmp();
static int strhash();
static struct st_hash_type type_strhash = {
strcmp,
strhash,
};
void *xmalloc();
void *xcalloc();
void *xrealloc();
static void rehash();
#define max(a,b) ((a) > (b) ? (a) : (b))
#define nil(type) ((type*)0)
#define alloc(type) (type*)xmalloc((unsigned)sizeof(type))
#define Calloc(n,s) (char*)xcalloc((n),(s))
#define EQUAL(table, x, y) ((*table->type->compare)(x, y) == 0)
#define do_hash(key, table) (*(table)->type->hash)((key), (table)->num_bins)
st_table*
st_init_table_with_size(type, size)
struct st_hash_type *type;
int size;
{
st_table *tbl;
if (size == 0) size = ST_DEFAULT_INIT_TABLE_SIZE;
else size /= ST_DEFAULT_MAX_DENSITY*0.87;
if (size < ST_DEFAULT_INIT_TABLE_SIZE)
size = ST_DEFAULT_INIT_TABLE_SIZE;
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()
{
return st_init_table(&type_numhash);
}
st_table*
st_init_strtable()
{
return st_init_table(&type_strhash);
}
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 != nil(st_table_entry)) {
next = ptr->next;
free((char*)ptr);
ptr = next;
}
}
free((char*)table->bins);
free((char*)table);
}
#define PTR_NOT_EQUAL(table, ptr, key) \
(ptr != nil(st_table_entry) && !EQUAL(table, key, (ptr)->key))
#define FIND_ENTRY(table, ptr, hash_val) \
ptr = (table)->bins[hash_val];\
if (PTR_NOT_EQUAL(table, ptr, key)) {\
while (PTR_NOT_EQUAL(table, ptr->next, key)) {\
ptr = ptr->next;\
}\
ptr = ptr->next;\
}
int
st_lookup(table, key, value)
st_table *table;
register char *key;
char **value;
{
int hash_val;
register st_table_entry *ptr;
hash_val = do_hash(key, table);
FIND_ENTRY(table, ptr, hash_val);
if (ptr == nil(st_table_entry)) {
return 0;
} else {
if (value != nil(char*)) *value = ptr->record;
return 1;
}
}
#define ADD_DIRECT(table, key, value, hash_val, tbl)\
{\
if (table->num_entries/table->num_bins > ST_DEFAULT_MAX_DENSITY) {\
rehash(table);\
hash_val = do_hash(key, table);\
}\
\
tbl = alloc(st_table_entry);\
\
tbl->key = key;\
tbl->record = value;\
tbl->next = table->bins[hash_val];\
table->bins[hash_val] = tbl;\
table->num_entries++;\
}
int
st_insert(table, key, value)
register st_table *table;
register char *key;
char *value;
{
int hash_val;
st_table_entry *tbl;
register st_table_entry *ptr;
hash_val = do_hash(key, table);
FIND_ENTRY(table, ptr, hash_val);
if (ptr == nil(st_table_entry)) {
ADD_DIRECT(table,key,value,hash_val,tbl);
return 0;
} else {
ptr->record = value;
return 1;
}
}
void
st_add_direct(table, key, value)
st_table *table;
char *key;
char *value;
{
int hash_val;
st_table_entry *tbl;
hash_val = do_hash(key, table);
ADD_DIRECT(table, key, value, hash_val, tbl);
}
int
st_find_or_add(table, key, slot)
st_table *table;
char *key;
char ***slot;
{
int hash_val;
st_table_entry *tbl, *ptr;
hash_val = do_hash(key, table);
FIND_ENTRY(table, ptr, hash_val);
if (ptr == nil(st_table_entry)) {
ADD_DIRECT(table, key, (char*)0, hash_val, tbl)
if (slot != nil(char**)) *slot = &tbl->record;
return 0;
} else {
if (slot != nil(char**)) *slot = &ptr->record;
return 1;
}
}
static void
rehash(table)
register st_table *table;
{
register st_table_entry *ptr, *next, **old_bins = table->bins;
int i, old_num_bins = table->num_bins, hash_val;
table->num_bins = 1.79*old_num_bins;
if (table->num_bins%2 == 0) {
table->num_bins += 1;
}
table->num_entries = 0;
table->bins = (st_table_entry **)
Calloc((unsigned)table->num_bins, sizeof(st_table_entry*));
for(i = 0; i < old_num_bins ; i++) {
ptr = old_bins[i];
while (ptr != nil(st_table_entry)) {
next = ptr->next;
hash_val = do_hash(ptr->key, table);
ptr->next = table->bins[hash_val];
table->bins[hash_val] = ptr;
table->num_entries++;
ptr = next;
}
}
free((char*)old_bins);
}
st_table*
st_copy(old_table)
st_table *old_table;
{
st_table *new_table;
st_table_entry *ptr, *tbl;
int i, num_bins = old_table->num_bins;
new_table = alloc(st_table);
if (new_table == nil(st_table)) {
return nil(st_table);
}
*new_table = *old_table;
new_table->bins = (st_table_entry**)
Calloc((unsigned)num_bins, sizeof(st_table_entry*));
if (new_table->bins == nil(st_table_entry*)) {
free((char*)new_table);
return nil(st_table);
}
for(i = 0; i < num_bins ; i++) {
new_table->bins[i] = nil(st_table_entry);
ptr = old_table->bins[i];
while (ptr != nil(st_table_entry)) {
tbl = alloc(st_table_entry);
if (tbl == nil(st_table_entry)) {
free((char*)new_table->bins);
free((char*)new_table);
return nil(st_table);
}
*tbl = *ptr;
tbl->next = new_table->bins[i];
new_table->bins[i] = tbl;
ptr = ptr->next;
}
}
return new_table;
}
int
st_delete(table, key, value)
register st_table *table;
register char **key;
char **value;
{
int hash_val;
st_table_entry *tmp;
register st_table_entry *ptr;
hash_val = do_hash(*key, table);
ptr = table->bins[hash_val];
if (ptr == nil(st_table_entry)) {
if (value != nil(char*)) *value = nil(char);
return 0;
}
if (EQUAL(table, *key, ptr->key)) {
table->bins[hash_val] = ptr->next;
table->num_entries--;
if (value != nil(char*)) *value = ptr->record;
*key = ptr->key;
free((char*)ptr);
return 1;
}
for(; ptr->next != nil(st_table_entry); ptr = ptr->next) {
if (EQUAL(table, ptr->next->key, *key)) {
tmp = ptr->next;
ptr->next = ptr->next->next;
table->num_entries--;
if (value != nil(char*)) *value = tmp->record;
*key = tmp->key;
free((char*)tmp);
return 1;
}
}
return 0;
}
int
st_delete_safe(table, key, value, never)
register st_table *table;
register char **key;
char **value;
char *never;
{
int hash_val;
register st_table_entry *ptr;
hash_val = do_hash(*key, table);
ptr = table->bins[hash_val];
if (ptr == nil(st_table_entry)) {
if (value != nil(char*)) *value = nil(char);
return 0;
}
if (EQUAL(table, *key, ptr->key)) {
table->num_entries--;
*key = ptr->key;
if (value != nil(char*)) *value = ptr->record;
ptr->key = ptr->record = never;
return 1;
}
for(; ptr->next != nil(st_table_entry); ptr = ptr->next) {
if (EQUAL(table, ptr->next->key, *key)) {
table->num_entries--;
*key = ptr->key;
if (value != nil(char*)) *value = ptr->record;
ptr->key = ptr->record = never;
return 1;
}
}
return 0;
}
void
st_foreach(table, func, arg)
st_table *table;
enum st_retval (*func)();
char *arg;
{
st_table_entry *ptr, *last, *tmp;
enum st_retval retval;
int i;
for(i = 0; i < table->num_bins; i++) {
last = nil(st_table_entry);
for(ptr = table->bins[i]; ptr != nil(st_table_entry);) {
retval = (*func)(ptr->key, ptr->record, arg);
switch (retval) {
case ST_CONTINUE:
last = ptr;
ptr = ptr->next;
break;
case ST_STOP:
return;
case ST_DELETE:
tmp = ptr;
if (last == nil(st_table_entry)) {
table->bins[i] = ptr->next;
} else {
last->next = ptr->next;
}
ptr = ptr->next;
free((char*)tmp);
table->num_entries--;
}
}
}
}
static int
strhash(string, modulus)
register char *string;
int modulus;
{
register int val = 0;
register int c;
while ((c = *string++) != '\0') {
val = val*997 + c;
}
return ((val < 0) ? -val : val)%modulus;
}
static int
numcmp(x, y)
int x, y;
{
return x != y;
}
static int
numhash(n, modulus)
int n;
int modulus;
{
return n % modulus;
}
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