kernel/util: Add bitmap implementation

2013-10-03 04:27:49 +02:00
parent 7087b865e2
commit 149c82a8ec
4 changed files with 168 additions and 0 deletions
@@ -38,5 +38,23 @@ countSetBits(uint32 v)
 }


+static inline uint32
+log2(uint32 v)
+{
+	static const int MultiplyDeBruijnBitPosition[32] = {
+		0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
+		8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31
+	};
+
+	v |= v >> 1;
+	v |= v >> 2;
+	v |= v >> 4;
+	v |= v >> 8;
+	v |= v >> 16;
+
+	return MultiplyDeBruijnBitPosition[(uint32)(v * 0x07C4ACDDU) >> 27];
+}
+
+
 #endif	// KERNEL_UTIL_RANDOM_H

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2013 Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *		Paweł Dziepak, [email protected]
+ */
+#ifndef KERNEL_UTIL_BITMAP_H
+#define KERNEL_UTIL_BITMAP_H
+
+
+#include <Debug.h>
+#include <SupportDefs.h>
+
+
+class Bitmap {
+public:
+						Bitmap(int bitCount);
+						~Bitmap();
+
+	inline	status_t	GetInitStatus();
+
+	inline	bool		Get(int index) const;
+	inline	void		Set(int index);
+	inline	void		Clear(int index);
+
+			int			GetHighestSet() const;
+
+private:
+			status_t	fInitStatus;
+
+			int			fElementsCount;
+			int			fSize;
+			addr_t*		fBits;
+
+	static	const int	kBitsPerElement;
+};
+
+
+status_t
+Bitmap::GetInitStatus()
+{
+	return fInitStatus;
+}
+
+
+bool
+Bitmap::Get(int index) const
+{
+	ASSERT(index < fSize);
+
+	const int kArrayElement = index / kBitsPerElement;
+	const addr_t kBitMask = addr_t(1) << (index % kBitsPerElement);
+	return fBits[kArrayElement] & kBitMask;
+}
+
+
+void
+Bitmap::Set(int index)
+{
+	ASSERT(index < fSize);
+
+	const int kArrayElement = index / kBitsPerElement;
+	const addr_t kBitMask = addr_t(1) << (index % kBitsPerElement);
+	fBits[kArrayElement] |= kBitMask;
+}
+
+
+void
+Bitmap::Clear(int index)
+{
+	ASSERT(index < fSize);
+
+	const int kArrayElement = index / kBitsPerElement;
+	const addr_t kBitMask = addr_t(1) << (index % kBitsPerElement);
+	fBits[kArrayElement] &= ~addr_t(kBitMask);
+}
+
+
+#endif	// KERNEL_UTIL_BITMAP_H
+