79 lines
1.3 KiB
C++
79 lines
1.3 KiB
C++
/*
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* Copyright 2009, Haiku, Inc. All Rights Reserved.
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* Distributed under the terms of the MIT License.
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*
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* Authors:
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* Brecht Machiels, brecht@mos6581.org
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*/
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#ifndef _BINARY_UTILS_H
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#define _BINARY_UTILS_H
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/* macro for a one-bit bitmask
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*/
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#define BIT(n) (1ULL << n)
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/* macro/templates to create bitmasks
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*/
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#define BITMASK(high, low) ((unsigned long long)(BitMask<high, low>::value))
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template<int h, int l>
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struct BitMask
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{
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enum { value = (BitMask<h-l-1,0>::value +
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(1ULL << h - l)) << l };
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};
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template<>
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struct BitMask<-1,0>
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{
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enum { value = 0ULL };
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};
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/* macro/templates to enter binary constants
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*/
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#define BINARY(binstring) ((unsigned long long)(Binary<0##binstring>::value))
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// http://www.eptacom.net/pubblicazioni/pub_eng/binary.html
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template<const unsigned long long N> struct Binary
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{
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enum { value = (N % 8ULL) + 2ULL * Binary<N / 8ULL>::value };
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};
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template<>
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struct Binary<0>
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{
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enum { value = 0ULL } ;
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};
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/* macro/templates to determine offset
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NOTE: broken for high bit indices
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*/
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#define MASKOFFSET(mask) (MaskOffset<mask, (mask & 1UL)>::count)
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template<const unsigned long mask, unsigned int firstBit>
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struct MaskOffset
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{
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enum { count = MaskOffset<(mask >> 1), ((mask >> 1) & 1UL)>::count + 1 };
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};
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template<const unsigned long mask>
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struct MaskOffset<mask, 1>
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{
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enum { count = 0 };
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};
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#endif // _BINARY_UTILS_H
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