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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"

#ifdef USE_CWGUSI
#include <stdlib.h>
#endif

typedef struct st_table_entry st_table_entry;

struct st_table_entry {
    unsigned int hash;
    char *key;
    char *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();
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 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) (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 long primes[] = {
8 + 3,
16 + 3,
32 + 5,
64 + 3,
128 + 3,
256 + 29,
512 + 17,
1024 + 9,
2048 + 5,
4096 + 83,
8192 + 27,
16384 + 43,
32768 + 3,
65536 + 45,
131072 + 9,
262144 + 39,
524288 + 39,
1048576 + 9,
2097152 + 5,
4194304 + 3,
8388608 + 33,
16777216 + 27,
33554432 + 9,
67108864 + 71,
134217728 + 39,
268435456 + 9,
536870912 + 5,
1073741824 + 83,
0
};

static int
new_size(size)
    int size;
{
    int i, newsize;

    for (i = 0, newsize = MINSIZE;
i < sizeof(primes)/sizeof(primes[0]);
i++, newsize <<= 1)
    {
if (newsize > size) return primes[i];
    }
    /* Ran out of polynomials */
    return -1; /* should raise exception */
}

st_table*
st_init_table_with_size(type, size)
    struct st_hash_type *type;
    int size;
{
    st_table *tbl;

    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()
{
    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()
{
    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))

#define FIND_ENTRY(table, ptr, hash_val, bin_pos) \
bin_pos = hash_val%(table)->num_bins;\
ptr = (table)->bins[bin_pos];\
if (PTR_NOT_EQUAL(table, ptr, hash_val, key)) {\
while (PTR_NOT_EQUAL(table, ptr->next, hash_val, key)) {\
ptr = ptr->next;\
}\
ptr = ptr->next;\
}

int
st_lookup(table, key, value)
    st_table *table;
    register char *key;
    char **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)\
{\
st_table_entry *tbl;\
if (table->num_entries/table->num_bins > ST_DEFAULT_MAX_DENSITY) {\
rehash(table);\
bin_pos = hash_val % table->num_bins;\
}\
\
tbl = alloc(st_table_entry);\
\
tbl->hash = hash_val;\
tbl->key = key;\
tbl->record = value;\
tbl->next = table->bins[bin_pos];\
table->bins[bin_pos] = tbl;\
table->num_entries++;\
}

int
st_insert(table, key, value)
    register st_table *table;
    register char *key;
    char *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;
    char *key;
    char *value;
{
    unsigned int hash_val, bin_pos;
    st_table_entry *tbl;

    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);
    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, *tbl;
    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) {
tbl = alloc(st_table_entry);
if (tbl == 0) {
free(new_table->bins);
free(new_table);
return 0;
}
*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;
{
    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 char **key;
    char **value;
    char *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;
    }

    if (EQUAL(table, *key, ptr->key)) {
table->num_entries--;
*key = ptr->key;
if (value != 0) *value = ptr->record;
ptr->key = ptr->record = never;
return 1;
    }

    for(; ptr->next != 0; ptr = ptr->next) {
if (EQUAL(table, ptr->next->key, *key)) {
table->num_entries--;
*key = ptr->key;
if (value != 0) *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 = 0;
for(ptr = table->bins[i]; ptr != 0;) {
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 == 0) {
table->bins[i] = ptr->next;
} else {
last->next = ptr->next;
}
ptr = ptr->next;
free(tmp);
table->num_entries--;
}
}
    }
}

static int
strhash(string)
    register char *string;
{
    register int val = 0;
    register int c;

    while ((c = *string++) != '\0') {
val = val*997 + c;
    }

    return val;
}

static int
numcmp(x, y)
    int x, y;
{
    return x != y;
}

static int
numhash(n)
    int n;
{
    return n;
}
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