1 files changed, 61 insertions, 0 deletions
diff --git a/src/wincompat/include/hashtable.h b/src/wincompat/include/hashtable.h
new file mode 100644
index 0000000..bd83bbb
--- /dev/null
+++ b/src/wincompat/include/hashtable.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2018-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+#ifndef _HASHTABLE_H
+#define _HASHTABLE_H
+
+#include <string.h>
+
+enum { HASHTABLE_ENTRY_BUCKETS_POW2 = 1 << 10 };
+
+struct hashtable_entry {
+	char *key;
+	void *value;
+	struct hashtable_entry *next;
+};
+
+struct hashtable {
+	struct hashtable_entry *entry_buckets[HASHTABLE_ENTRY_BUCKETS_POW2];
+};
+
+static unsigned int hashtable_bucket(const char *str)
+{
+	unsigned long hash = 5381;
+	char c;
+	while ((c = *str++))
+		hash = ((hash << 5) + hash) ^ c;
+	return hash & (HASHTABLE_ENTRY_BUCKETS_POW2 - 1);
+}
+
+static struct hashtable_entry *hashtable_find_entry(struct hashtable *hashtable, const char *key)
+{
+	struct hashtable_entry *entry;
+	for (entry = hashtable->entry_buckets[hashtable_bucket(key)]; entry; entry = entry->next) {
+		if (!strcmp(entry->key, key))
+			return entry;
+	}
+	return NULL;
+}
+
+static struct hashtable_entry *hashtable_find_or_insert_entry(struct hashtable *hashtable, const char *key)
+{
+	struct hashtable_entry **entry;
+	for (entry = &hashtable->entry_buckets[hashtable_bucket(key)]; *entry; entry = &(*entry)->next) {
+		if (!strcmp((*entry)->key, key))
+			return *entry;
+	}
+	*entry = calloc(1, sizeof(**entry));
+	if (!*entry)
+		return NULL;
+	(*entry)->key = strdup(key);
+	if (!(*entry)->key) {
+		free(*entry);
+		*entry = NULL;
+		return NULL;
+	}
+	return *entry;
+}
+
+#endif