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GEL
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GEL is a library for Geometry and Linear Algebra
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/Users/jab/Documents/Teaching/02585/GEL2_and_demos/GEL/src/CGLA/BitMask.h
00001 #ifndef __CGLA__BITMASK_H__ 00002 #define __CGLA__BITMASK_H__ 00003 00004 #include "Vec3i.h" 00005 00006 namespace CGLA 00007 { 00008 const int MASKS[33] = 00009 { 00010 0x00000000, 00011 0x00000001, 00012 0x00000003, 00013 0x00000007, 00014 0x0000000f, 00015 0x0000001f, 00016 0x0000003f, 00017 0x0000007f, 00018 0x000000ff, 00019 0x000001ff, 00020 0x000003ff, 00021 0x000007ff, 00022 0x00000fff, 00023 0x00001fff, 00024 0x00003fff, 00025 0x00007fff, 00026 0x0000ffff, 00027 0x0001ffff, 00028 0x0003ffff, 00029 0x0007ffff, 00030 0x000fffff, 00031 0x001fffff, 00032 0x003fffff, 00033 0x007fffff, 00034 0x00ffffff, 00035 0x01ffffff, 00036 0x03ffffff, 00037 0x07ffffff, 00038 0x0fffffff, 00039 0x1fffffff, 00040 0x3fffffff, 00041 0x7fffffff, 00042 0xffffffff 00043 }; 00044 00050 class BitMask 00051 { 00052 int fb, lb, bdiff; 00053 int msk; 00054 00055 public: 00056 00059 BitMask(int _fb, int _lb): 00060 fb(_fb), lb(_lb), 00061 bdiff(lb-fb+1), msk(MASKS[bdiff]<<fb) 00062 {} 00063 00065 BitMask(int num): 00066 fb(0),lb(two_to_what_power(num)-1), 00067 bdiff(lb-fb+1), msk(MASKS[bdiff]<<fb) 00068 {} 00069 00071 BitMask(): 00072 fb(0), lb(15), 00073 bdiff(lb-fb+1), msk(MASKS[bdiff]<<fb) 00074 {} 00075 00077 int first_bit() const {return fb;} 00078 00080 int last_bit() const {return lb;} 00081 00083 int no_bits() const {return bdiff;} 00084 00086 int mask(int var) const {return msk&var;} 00087 00090 int mask_shift(int var) const {return (msk&var)>>fb;} 00091 00093 Vec3i mask(const Vec3i& v) const 00094 { 00095 return Vec3i(mask(v[0]),mask(v[1]),mask(v[2])); 00096 } 00097 00099 Vec3i maskshift(const Vec3i& v) const 00100 { 00101 return Vec3i(mask_shift(v[0]),mask_shift(v[1]),mask_shift(v[2])); 00102 } 00103 00104 }; 00105 00106 } 00107 #endif
