Initial checkin of gRPC to third_party/

third_party/grpc/include/grpc/support/avl.h

Index: third_party/grpc/include/grpc/support/avl.h
diff --git a/third_party/grpc/include/grpc/support/avl.h b/third_party/grpc/include/grpc/support/avl.h
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+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS 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 COPYRIGHT
+ * OWNER OR 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.
+ *
+ */
+
+#ifndef GRPC_SUPPORT_AVL_H
+#define GRPC_SUPPORT_AVL_H
+
+#include <grpc/support/sync.h>
+
+/** internal node of an AVL tree */
+typedef struct gpr_avl_node {
+  gpr_refcount refs;
+  void *key;
+  void *value;
+  struct gpr_avl_node *left;
+  struct gpr_avl_node *right;
+  long height;
+} gpr_avl_node;
+
+typedef struct gpr_avl_vtable {
+  /** destroy a key */
+  void (*destroy_key)(void *key);
+  /** copy a key, returning new value */
+  void *(*copy_key)(void *key);
+  /** compare key1, key2; return <0 if key1 < key2,
+      >0 if key1 > key2, 0 if key1 == key2 */
+  long (*compare_keys)(void *key1, void *key2);
+  /** destroy a value */
+  void (*destroy_value)(void *value);
+  /** copy a value */
+  void *(*copy_value)(void *value);
+} gpr_avl_vtable;
+
+/** "pointer" to an AVL tree - this is a reference
+    counted object - use gpr_avl_ref to add a reference,
+    gpr_avl_unref when done with a reference */
+typedef struct gpr_avl {
+  const gpr_avl_vtable *vtable;
+  gpr_avl_node *root;
+} gpr_avl;
+
+/** create an immutable AVL tree */
+GPRAPI gpr_avl gpr_avl_create(const gpr_avl_vtable *vtable);
+/** add a reference to an existing tree - returns
+    the tree as a convenience */
+GPRAPI gpr_avl gpr_avl_ref(gpr_avl avl);
+/** remove a reference to a tree - destroying it if there
+    are no references left */
+GPRAPI void gpr_avl_unref(gpr_avl avl);
+/** return a new tree with (key, value) added to avl.
+    implicitly unrefs avl to allow easy chaining.
+    if key exists in avl, the new tree's key entry updated
+    (i.e. a duplicate is not created) */
+GPRAPI gpr_avl gpr_avl_add(gpr_avl avl, void *key, void *value);
+/** return a new tree with key deleted
+    implicitly unrefs avl to allow easy chaining. */
+GPRAPI gpr_avl gpr_avl_remove(gpr_avl avl, void *key);
+/** lookup key, and return the associated value.
+    does not mutate avl.
+    returns NULL if key is not found. */
+GPRAPI void *gpr_avl_get(gpr_avl avl, void *key);
+
+#endif /* GRPC_SUPPORT_AVL_H */