From 84adefa331c4159d432d22840663c38f155cd4c1 Mon Sep 17 00:00:00 2001
From: Erlang/OTP <otp@erlang.org>
Date: Fri, 20 Nov 2009 14:54:40 +0000
Subject: The R13B03 release.

---
 lib/erl_interface/src/registry/hash_insert.c | 108 +++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 lib/erl_interface/src/registry/hash_insert.c

(limited to 'lib/erl_interface/src/registry/hash_insert.c')

diff --git a/lib/erl_interface/src/registry/hash_insert.c b/lib/erl_interface/src/registry/hash_insert.c
new file mode 100644
index 0000000000..dbe76282ae
--- /dev/null
+++ b/lib/erl_interface/src/registry/hash_insert.c
@@ -0,0 +1,108 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 1998-2009. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ *
+
+ */
+#include <stdlib.h>
+#include <string.h>
+#include "hash.h"
+
+/* this function returns a bucket - from the freelist if one was found
+ * there, or from malloc(). Only "small" buckets, i.e. those whose
+ * keys are short enough to be stored in the bucket itself, are saved
+ * on the freelist.
+ */
+static ei_bucket *ei_hash_bmalloc(ei_hash *tab)
+{
+  ei_bucket *new;
+  
+  if (tab->freelist) {
+    new = tab->freelist;
+    tab->freelist = new->next;
+    /* fprintf(stderr,"getting bucket from freelist\n"); */
+  }
+  else {
+    new = malloc(sizeof(*new));
+    /* fprintf(stderr,"allocating new (small) bucket\n"); */
+  }
+
+  return new;
+}
+
+/* insert a new key-value pair. The old value (if any) is returned. If
+ * the malloc fails the function returns NULL. This is potentially a
+ * problem since the function returns the same thing when malloc fails
+ * as when a item is inserted that did not previously exist in the
+ * table. */
+void *ei_hash_insert(ei_hash *tab, const char *key, const void *value) 
+{
+  const void *oldval=NULL;
+  ei_bucket *b=NULL;
+  int h, rh;
+
+  rh = tab->hash(key);
+  h =  rh % tab->size;
+
+  b=tab->tab[h];
+  while (b) {
+    if ((rh == b->rawhash) && (!strcmp(key,b->key)))
+      break;
+    b=b->next;
+  }
+
+  if (b) {
+    /* replace existing value, return old value */
+    oldval = b->value;
+    b->value = value;
+  }
+  else {
+    int keylen = strlen(key);
+    
+    /* this element is new */
+    if (keylen < EI_SMALLKEY) {
+      /* short keys stored directly in bucket */
+      /* try to get bucket from freelist */
+      if ((b = ei_hash_bmalloc(tab)) == NULL) return NULL;
+      b->key = b->keybuf;
+    }
+    else {
+      /* for longer keys we allocate space */
+      int keypos=sizeof(*b);
+
+      ei_align(keypos);
+      if ((b = malloc(keypos+keylen+1)) == NULL) return NULL;
+      b->key = (char *)b + keypos;
+      /* fprintf(stderr,"allocating new (large) bucket\n"); */
+    }
+
+    /* fill in the blanks */
+    b->rawhash = rh;
+    strcpy((char *)b->key,key);
+    b->value = value;
+
+    /* some statistiscs */
+    if (!tab->tab[h]) tab->npos++;
+    tab->nelem++;
+
+    /* link in the new element */
+    b->next = tab->tab[h];
+    tab->tab[h] = b;
+  }
+  return (void *)oldval;
+}
+
-- 
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