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-rw-r--r--st.c365
1 files changed, 365 insertions, 0 deletions
diff --git a/st.c b/st.c
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--- /dev/null
+++ b/st.c
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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";
+#ifndef lint
+static char *rcsid = "$Header: /work/cvsroot/ruby/st.c,v 1.2 1994/06/27 15:48:41 matz Exp $";
+#endif
+
+#include <stdio.h>
+#include "st.h"
+
+extern void *xmalloc();
+static 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))
+
+ /*
+ * 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
+ *
+ * DEFAULT_GROW_FACTOR is the amount the hash table is expanded after
+ * the density has reached max_density
+ */
+
+#define EQUAL(func, x, y) \
+ ((func == ST_NUMCMP) ? ((x) == (y)) : ((*func)((x), (y)) == 0))
+
+/*#define do_hash(key, table) (*table->hash)(key, table->num_bins)*/
+
+#define do_hash(key, table)\
+ ((table->hash == ST_PTRHASH) ? (((int) (key) >> 2) % table->num_bins) :\
+ (table->hash == ST_NUMHASH) ? ((int) (key) % table->num_bins) :\
+ (*table->hash)((key), table->num_bins))
+
+st_table *st_init_table_with_params(compare, hash, size, density, grow_factor,
+ reorder_flag)
+int (*compare)();
+int (*hash)();
+int size;
+int density;
+double grow_factor;
+int reorder_flag;
+{
+ st_table *tbl;
+
+ tbl = alloc(st_table);
+ tbl->compare = compare;
+ tbl->hash = hash;
+ tbl->num_entries = 0;
+ tbl->max_density = density;
+ tbl->grow_factor = grow_factor;
+ tbl->reorder_flag = reorder_flag;
+ tbl->num_bins = size;
+ tbl->bins =
+ (st_table_entry **) Calloc((unsigned)size, sizeof(st_table_entry *));
+ return tbl;
+}
+
+st_table *st_init_table(compare, hash)
+int (*compare)();
+int (*hash)();
+{
+ return st_init_table_with_params(compare, hash, ST_DEFAULT_INIT_TABLE_SIZE,
+ ST_DEFAULT_MAX_DENSITY,
+ ST_DEFAULT_GROW_FACTOR,
+ ST_DEFAULT_REORDER_FLAG);
+}
+
+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->compare, 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;\
+ }\
+ if (ptr->next != nil(st_table_entry) && (table)->reorder_flag) {\
+ st_table_entry *_tmp = (ptr)->next;\
+ (ptr)->next = (ptr)->next->next;\
+ _tmp->next = (table)->bins[hash_val];\
+ (table)->bins[hash_val] = _tmp;\
+ ptr = _tmp;\
+ } else {\
+ ptr = ptr->next;\
+ }\
+}
+
+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 > table->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++;\
+}
+
+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;
+ }
+}
+
+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);
+}
+
+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 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 = table->grow_factor*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;
+}
+
+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->compare, *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->compare, 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;
+}
+
+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);
+ }
+ }
+ }
+}
+
+st_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;
+}