Import support for hash tables.

git-svn-id: http://svn.apache.org/repos/asf/apr/apr/trunk@60019 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 196 insertions, 0 deletions

diff --git a/include/apr_hash.h b/include/apr_hash.h
new file mode 100644
index 000000000..f93c4b06a
--- /dev/null
+++ b/include/apr_hash.h
@@ -0,0 +1,196 @@
+/* ====================================================================
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2000 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution,
+ *    if any, must include the following acknowledgment:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowledgment may appear in the software itself,
+ *    if and wherever such third-party acknowledgments normally appear.
+ *
+ * 4. The names "Apache" and "Apache Software Foundation" must
+ *    not be used to endorse or promote products derived from this
+ *    software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache",
+ *    nor may "Apache" appear in their name, without prior written
+ *    permission of the Apache Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ * Portions of this software are based upon public domain software
+ * originally written at the National Center for Supercomputing Applications,
+ * University of Illinois, Urbana-Champaign.
+ */
+
+#ifndef ap_HASH_H
+#define ap_HASH_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Abstract type for hash tables.
+ */
+typedef struct ap_hash_t ap_hash_t;
+
+/*
+ * Abstract type for scanning hash tables.
+ */
+typedef struct ap_hash_index_t ap_hash_index_t;
+
+/*
+
+=head1 ap_hash_t *ap_make_hash(ap_pool_t *pool)
+
+B<Create a hash table within a pool.>
+
+=cut
+*/
+ap_hash_t *ap_make_hash(ap_pool_t *pool);
+
+/*
+
+=head1 void ap_hash_set(ap_hash_t *ht, void *key, size_t klen, void *val)
+
+B<Associate a value with a key in a hash table.>
+
+    arg 1) The hash table
+    arg 2) Pointer to the key
+    arg 3) Length of the key
+    arg 4) Value to associate with the key
+
+If the value is NULL the hash entry is deleted.
+
+=cut
+*/
+void ap_hash_set(ap_hash_t *ht, void *key, size_t klen, void *val);
+
+/*
+
+=head1 void *ap_hash_get(ap_hash_t *ht, void *key, size_t klen)
+
+B<Look up the value associated with a key in a hash table.>
+
+    arg 1) The hash table
+    arg 2) Pointer to the key
+    arg 3) Length of the key
+
+Returns NULL if the key is not present.
+
+=cut
+*/
+void *ap_hash_get(ap_hash_t *ht, void *key, size_t klen);
+
+/*
+
+=head1 ap_hash_index_t *ap_hash_first(ap_hash_t *ht)
+
+B<Start iterating over the entries in a hash table.>
+
+    arg 1) The hash table
+
+Returns a pointer to the iteration state, or NULL if there are no
+entries.
+
+=cut
+*/
+ap_hash_index_t *ap_hash_first(ap_hash_t *ht);
+
+/*
+
+=head1 ap_hash_index_t *ap_hash_next(ap_hash_index_t *hi)
+
+B<Continue iterating over the entries in a hash table.>
+
+    arg 1) The iteration state
+
+Returns a pointer to the updated iteration state, or NULL if there are
+no more entries.
+
+*/
+ap_hash_index_t *ap_hash_next(ap_hash_index_t *hi);
+
+/*
+
+=head1 void ap_hash_this(ap_hash_index_t *hi, void **key, size_t *klen, void **val)
+
+B<Get the current entry's details from the iteration state.>
+
+    arg 1) The iteration state
+    arg 2) Return pointer for the pointer to the key.
+    arg 3) Return pointer for the key length.
+    arg 4) Return pointer for the associated value.
+
+The return pointers should point to a variable that will be set to the
+corresponding data, or they may be NULL if the data isn't interesting.
+
+=cut
+*/
+void ap_hash_this(ap_hash_index_t *hi, void **key, size_t *klen, void **val);
+
+/*
+
+=head2 Using the iteration functions
+
+Example:
+
+    int sum_values(ap_hash_t *ht)
+    {
+        ap_hash_index_t *hi;
+	void *val;
+	int sum = 0;
+	for (hi = ap_hash_first(ht); hi; hi = ap_hash_next(hi)) {
+	    ap_hash_this(hi, NULL, NULL, &val);
+	    sum += *(int *)val;
+	}
+	return sum;
+    }
+
+There is no restriction on adding or deleting hash entries during an
+iteration (although the results may be unpredictable unless all you do
+is delete the current entry) and multiple iterations can be in
+progress at the same time.
+
+=cut
+*/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* !ap_HASH_H */