X-Git-Url: http://andersk.mit.edu/gitweb/moira.git/blobdiff_plain/07d9123cf8f28a777794f567b36490841300b6a6..fc2f4a27ed42bcff7c3c5ce00573210110b45b21:/lib/hash.c

diff --git a/lib/hash.c b/lib/hash.c
index 1d61cbb3..e34e289f 100644
--- a/lib/hash.c
+++ b/lib/hash.c
@@ -1,12 +1,21 @@
 /* $Header$
  *
  * Generic hash table routines.  Uses integer keys to store char * values.
+ *
+ *  (c) Copyright 1988 by the Massachusetts Institute of Technology.
+ *  For copying and distribution information, please see the file
+ *  <mit-copyright.h>.
  */
 
+#include <mit-copyright.h>
 #include <ctype.h>
-#include "sms_app.h"
-#define NULL 0
+#include <moira.h>
+#include <string.h>
 
+extern char *malloc();
+
+#define NULL 0
+#define hash_func(h, key) (key >= 0 ? (key % h->size) : (-key % h->size))
 
 /* Create a hash table.  The size is just a hint, not a maximum. */
 
@@ -16,9 +25,15 @@ int size;
     struct hash *h;
 
     h = (struct hash *) malloc(sizeof(struct hash));
+    if (h == (struct hash *) NULL)
+      return((struct hash *) NULL);
     h->size = size;
     h->data = (struct bucket **) malloc(size * sizeof(char *));
-    bzero(h->data, size * sizeof(char *));
+    if (h->data == (struct bucket **) NULL) {
+	free(h);
+	return((struct hash *) NULL);
+    }
+    memset(h->data, 0, size * sizeof(char *));
     return(h);
 }
 
@@ -32,7 +47,7 @@ register int key;
 {
     register struct bucket *b;
 
-    b = h->data[key % h->size];
+    b = h->data[hash_func(h, key)];
     while (b && b->key != key)
       b = b->next;
     if (b && b->key == key)
@@ -53,7 +68,7 @@ char *value;
 {
     register struct bucket *b;
 
-    b = h->data[key % h->size];
+    b = h->data[hash_func(h, key)];
     while (b && b->key != key)
       b = b->next;
     if (b && b->key == key) {
@@ -65,7 +80,7 @@ char *value;
 
 
 /* Store an item in the hash table.  Returns 0 if the key was not previously
- * there, or 1 if it was.
+ * there, 1 if it was, or -1 if we ran out of memory.
  */
 
 int hash_store(h, key, value)
@@ -75,9 +90,11 @@ char *value;
 {
     register struct bucket *b, **p;
 
-    p = &(h->data[key % h->size]);
+    p = &(h->data[hash_func(h, key)]);
     if (*p == NULL) {
 	b = *p = (struct bucket *) malloc(sizeof(struct bucket));
+	if (b == (struct bucket *) NULL)
+	  return(-1);
 	b->next = NULL;
 	b->key = key;
 	b->data = value;
@@ -91,6 +108,8 @@ char *value;
 	return(1);
     }
     b = *p = (struct bucket *) malloc(sizeof(struct bucket));
+    if (b == (struct bucket *) NULL)
+      return(-1);
     b->next = NULL;
     b->key = key;
     b->data = value;