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src/gallium/auxiliary/cso_cache/cso_hash.h

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+/**************************************************************************
+ *
+ * Copyright 2007 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+/**
+ * @file
+ * Hash table implementation.
+ *
+ * This file provides a hash implementation that is capable of dealing
+ * with collisions. It stores colliding entries in linked list. All
+ * functions operating on the hash return an iterator. The iterator
+ * itself points to the collision list. If there wasn't any collision
+ * the list will have just one entry, otherwise client code should
+ * iterate over the entries to find the exact entry among ones that
+ * had the same key (e.g. memcmp could be used on the data to check
+ * that)
+ *
+ * @author Zack Rusin <[email protected]>
+ */
+
+#ifndef CSO_HASH_H
+#define CSO_HASH_H
+
+#include "util/compiler.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+struct cso_node {
+   struct cso_node *next;
+   void *value;
+   unsigned key;
+};
+
+struct cso_hash_iter {
+   struct cso_hash *hash;
+   struct cso_node *node;
+};
+
+struct cso_hash {
+   struct cso_node *fakeNext;
+   struct cso_node **buckets;
+   struct cso_node *end;
+   int size;
+   short userNumBits;
+   short numBits;
+   int numBuckets;
+};
+
+
+void
+cso_hash_init(struct cso_hash *hash);
+
+void
+cso_hash_deinit(struct cso_hash *hash);
+
+int
+cso_hash_size(const struct cso_hash *hash);
+
+
+/**
+ * Adds a data with the given key to the hash. If entry with the given
+ * key is already in the hash, this current entry is instered before it
+ * in the collision list.
+ * Function returns iterator pointing to the inserted item in the hash.
+ */
+struct cso_hash_iter
+cso_hash_insert(struct cso_hash *hash, unsigned key, void *data);
+
+
+/**
+ * Removes the item pointed to by the current iterator from the hash.
+ * Note that the data itself is not erased and if it was a malloc'ed pointer
+ * it will have to be freed after calling this function by the callee.
+ * Function returns iterator pointing to the item after the removed one in
+ * the hash.
+ */
+struct cso_hash_iter
+cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter);
+
+void *
+cso_hash_take(struct cso_hash *hash, unsigned key);
+
+struct cso_hash_iter
+cso_hash_first_node(struct cso_hash *hash);
+
+/**
+ * Returns true if a value with the given key exists in the hash
+ */
+bool
+cso_hash_contains(struct cso_hash *hash, unsigned key);
+
+unsigned
+cso_hash_iter_key(struct cso_hash_iter iter);
+
+
+/**
+ * Convenience routine to iterate over the collision list while doing a memory
+ * comparison to see which entry in the list is a direct copy of our template
+ * and returns that entry.
+ */
+void *
+cso_hash_find_data_from_template(struct cso_hash *hash,
+                                 unsigned hash_key,
+                                 void *templ,
+                                 int size);
+
+struct cso_node *
+cso_hash_data_next(struct cso_node *node);
+
+
+static inline bool
+cso_hash_iter_is_null(struct cso_hash_iter iter)
+{
+   return !iter.node || iter.node == iter.hash->end;
+}
+
+
+static inline void *
+cso_hash_iter_data(struct cso_hash_iter iter)
+{
+   if (!iter.node || iter.hash->end == iter.node)
+      return NULL;
+   return iter.node->value;
+}
+
+
+static inline struct cso_node **
+cso_hash_find_node(struct cso_hash *hash, unsigned akey)
+{
+   struct cso_node **node;
+
+   if (hash->numBuckets) {
+      node = &hash->buckets[akey % hash->numBuckets];
+      assert(*node == hash->end || (*node)->next);
+      while (*node != hash->end && (*node)->key != akey)
+         node = &(*node)->next;
+   } else {
+      node = &hash->end;
+   }
+   return node;
+}
+
+
+/**
+ * Return an iterator pointing to the first entry in the collision list.
+ */
+static inline struct cso_hash_iter
+cso_hash_find(struct cso_hash *hash, unsigned key)
+{
+   struct cso_node **nextNode = cso_hash_find_node(hash, key);
+   struct cso_hash_iter iter = {hash, *nextNode};
+   return iter;
+}
+
+
+static inline struct cso_hash_iter
+cso_hash_iter_next(struct cso_hash_iter iter)
+{
+   struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
+   return next;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif