Move BitUtils.h outside of kernel directory

It is not specific to the kernel Change-Id: I334c39b39d74f61b30215fb5489dec09e318dacd Reviewed-on: https://review.haiku-os.org/c/haiku/+/10049 Tested-by: Commit checker robot <[email protected]> Reviewed-by: Adrien Destugues <[email protected]>
2025-12-09 10:08:25 +00:00
parent 2172f376f8
commit cf930b7e6c
7 changed files with 10 additions and 6 deletions
@@ -1,140 +0,0 @@
-/*
- * Copyright 2013 Haiku, Inc. All rights reserved.
- * Distributed under the terms of the MIT License.
- *
- * Authors:
- *		Paweł Dziepak, [email protected]
- */
-#ifndef KERNEL_UTIL_BITUTIL_H
-#define KERNEL_UTIL_BITUTIL_H
-
-
-#include <string.h>
-
-#include <SupportDefs.h>
-
-
-// http://graphics.stanford.edu/~seander/bithacks.html
-static inline uint32
-next_power_of_2(uint32 v)
-{
-	v--;
-	v |= v >> 1;
-	v |= v >> 2;
-	v |= v >> 4;
-	v |= v >> 8;
-	v |= v >> 16;
-	v++;
-
-	return v;
-}
-
-
-// http://graphics.stanford.edu/~seander/bithacks.html
-static inline uint32
-count_set_bits(uint32 v)
-{
-	v = v - ((v >> 1) & 0x55555555);
-	v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
-	return (((v + (v >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24;
-}
-
-
-static inline uint32
-fls(uint32 value)
-{
-	if (value == 0)
-		return 0;
-
-#if __has_builtin(__builtin_clz)
-	return ((sizeof(value) * 8) - __builtin_clz(value));
-#else
-	// https://graphics.stanford.edu/~seander/bithacks.html#IntegerLog
-	static const uint32 masks[] = {
-		0xaaaaaaaa,
-		0xcccccccc,
-		0xf0f0f0f0,
-		0xff00ff00,
-		0xffff0000
-	};
-	uint32 result = (value & masks[0]) != 0;
-	for (int i = 4; i > 0; i--)
-		result |= ((value & masks[i]) != 0) << i;
-	return result + 1;
-#endif
-}
-
-
-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];
-}
-
-
-template<typename T>
-void
-bitmap_shift(T* bits, size_t bitCount, ssize_t shift)
-{
-	if (shift == 0)
-		return;
-
-	const size_t bitsPerElement = sizeof(T) * 8;
-	const size_t elementsCount = (bitCount + bitsPerElement - 1) / bitsPerElement;
-	const size_t absoluteShift = (shift > 0) ? shift : -shift;
-	const size_t nElements = absoluteShift / bitsPerElement;
-	const size_t nBits = absoluteShift % bitsPerElement;
-	if (nElements != 0) {
-		if (shift > 0) {
-			// "Left" shift.
-			memmove(&bits[nElements], bits, sizeof(T) * (elementsCount - nElements));
-			memset(bits, 0, sizeof(T) * nElements);
-		} else if (shift < 0) {
-			// "Right" shift.
-			memmove(bits, &bits[nElements], sizeof(T) * (elementsCount - nElements));
-			memset(&bits[elementsCount - nElements], 0, sizeof(T) * nElements);
-		}
-	}
-
-	// If the shift was by a multiple of the element size, nothing more to do.
-	if (nBits == 0)
-		return;
-
-	// One set of bits comes from the "current" element and are shifted in the
-	// direction of the shift; the other set comes from the next-processed
-	// element and are shifted in the opposite direction.
-	if (shift > 0) {
-		// "Left" shift.
-		for (ssize_t i = elementsCount - 1; i >= 0; i--) {
-			T low = 0;
-			if (i != 0)
-				low = bits[i - 1] >> (bitsPerElement - nBits);
-			const T high = bits[i] << nBits;
-			bits[i] = low | high;
-		}
-	} else if (shift < 0) {
-		// "Right" shift.
-		for (size_t i = 0; i < elementsCount; i++) {
-			const T low = bits[i] >> nBits;
-			T high = 0;
-			if (i != (elementsCount - 1))
-				high = bits[i + 1] << (bitsPerElement - nBits);
-			bits[i] = low | high;
-		}
-	}
-}
-
-
-#endif	// KERNEL_UTIL_BITUTIL_H
-