A helper datastructure for network buffers. Defines a fixed-size region of same-size data blocks, and maintains a reference count for each

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18896 a95241bf-73f2-0310-859d-f6bbb57e9c96
2006-09-21 02:40:20 +00:00
parent 46564600a4
commit b425ce77ad
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+/* General data region of fixed size data blocks
+ *
+ * Copyright 2006, Haiku, Inc.  All Rights Reserved
+ * Distributed under the terms of the MIT liscence.
+ *
+ * Authors:
+ *     Andrew Galante, [email protected]
+ */
+
+struct datastore {
+	void *store;		// ptr to data region
+	size_t blocksize;	// size of the blocks in the datastore
+	size_t blockcount;	// total number of blocks in the datastore
+	int32 *refcounts;		// array containing refcounts for each block.  a refcount of 0 is a free block
+	int lastfreed;		// index of last freed block
+	int nextfree;		// index of next free block
+};
+
+status_t init_datastore(struct datastore *store, size_t blocksize, int blockcount);	// initializes the datastore
+status_t uninit_datastore(struct datastore *store); // frees the memory used by the datastore
+void *get_datablock(struct datastore *store);	// returns a ptr to the first found free block, and increments its refcount
+void *get_datablock(struct datastore *store, void *block);	// increments the refcount of the specified block
+status_t put_datablock(struct datastore *store, void *block);	// decrements the refcount of the specified block
+
+// not thread safe - for amusement purposes only:
+int is_empty_datastore(struct datastore *store);	// returns nonzero if all refcounts are zero
+int is_full_datastore(struct datastore *store);		// returns nonzero if all refcounts are greater than zero