From 2fc06b877430cd58f435659fc04d1e4f0cde30b0 Mon Sep 17 00:00:00 2001
From: beveloper <beveloper@nowhere.fake>
Date: Fri, 29 Aug 2003 00:27:08 +0000
Subject: [PATCH] Replaced the broken BBlockCache implementation. According to
 the BeBook, it is NOT allowed to allocate one large pool, instead the memory
 blocks must be allocated individually. To achieve O(1) for both Save() and
 Get() function, only one list of free blocks is maintained.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4393 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 headers/os/support/BlockCache.h | 91 ++++++++++++++++++++-------------
 1 file changed, 56 insertions(+), 35 deletions(-)

diff --git a/headers/os/support/BlockCache.h b/headers/os/support/BlockCache.h
index 5ea28ef0cf..ce4f56d3e1 100644
--- a/headers/os/support/BlockCache.h
+++ b/headers/os/support/BlockCache.h
@@ -1,56 +1,77 @@
-//******************************************************************************
-//
-// File:			BlockCache.h		
-//
-// Description:		Manages a cache of same size blocks of memory
-//
-// Copyright (c) 2002 Massimiliano Origgi
-//
-// License:			
-//
-//******************************************************************************
-
+/*
+ * Copyright (c) 2003 Marcus Overhagen
+ * 
+ * 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, sublicense, 
+ * 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 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 NONINFRINGEMENT. IN NO EVENT SHALL THE 
+ * AUTHORS OR COPYRIGHT HOLDERS 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.
+ */
 #ifndef _BLOCK_CACHE_H
 #define _BLOCK_CACHE_H
 
 #include <BeBuild.h>
 #include <Locker.h>
 
-// Allocation type
-enum
-{
+/* The OpenBeOS implementation of the BBLockCache.
+ * A class used to manage a pool of memory blocks.
+ */
+
+/* The allocation type to be used in the constructor
+ */
+enum {
 	B_OBJECT_CACHE = 0,
 	B_MALLOC_CACHE = 1
 };
 
-
+/* The BBlockCache class:
+ */
 class BBlockCache
 {
 public:
+				BBlockCache(size_t cacheSize,
+							size_t blockSize,
+							uint32 allocationType);
+	virtual		~BBlockCache();
 
-					BBlockCache(size_t CacheSize, size_t BlockSize,	uint32 Type);
-virtual				~BBlockCache(void);
-
-		void		*Get(size_t BlockSize);
-		void		Save(void *Data, size_t BlockSize);
+	void *		Get(size_t blockSize);
+	void		Save(void *pointer, size_t blockSize);
 
+/* Private or reserved functions and data
+ */
 private:
+	virtual	void _ReservedBlockCache1();
+	virtual	void _ReservedBlockCache2();
 
-virtual	void		_ReservedBlockCache1();
-virtual	void		_ReservedBlockCache2();
+				BBlockCache(const BBlockCache &);
+	BBlockCache	&operator=(const BBlockCache &);
 
-					BBlockCache(const BBlockCache &);
-		BBlockCache	&operator=(const BBlockCache &);
+	struct _FreeBlock
+	{
+		uint32		magic1;
+		_FreeBlock *next;
+		uint32		magic2;
+	};
 
-		size_t		fCacheSize;
-		size_t		fBlockSize;
-		void		*fCache;
-		size_t			fMark;
-		BLocker		fLock;
-		void		*(*fAlloc)(size_t Size);
-		void		(*fFree)(void *Data);
-		
-		uint32		_reserved[2];
+	_FreeBlock *fFreeList;
+	size_t		fBlockSize;
+	int32		fExcessBlocks;
+	BLocker		fLocker;
+	void *		(*fAlloc)(size_t size);
+	void		(*fFree)(void *pointer);
+	uint32		_reserved[3];
 };
 
-#endif
+#endif /* _BLOCK_CACHE_H */