summaryrefslogtreecommitdiff
path: root/st.c
diff options
context:
space:
mode:
Diffstat (limited to 'st.c')
-rw-r--r--st.c483
1 files changed, 483 insertions, 0 deletions
diff --git a/st.c b/st.c
new file mode 100644
index 0000000..8c0a386
--- /dev/null
+++ b/st.c
@@ -0,0 +1,483 @@
+/* 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 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;
+
+ 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;
+}