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Alex Rivera
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I found some interesting bit twiddling in "source\common\unicode\utf.h" file of ICU library (International Components for Unicode). The bit twiddling is intended for checking whether a number is in a particular range. // Is a code point in a range of U+d800..U+dbff? #define U_IS_LEAD(c) (((c)&0xfffffc00)==0xd800) I have figured out the magic number (0xfffffc00) come from: MagicNumber = 0xffffffff - (HighBound - LowBound) However, I also found that the formula doesn't apply to every arbitrary range. Does somebody here know in what circumstance the formula works? Is there another bit twiddling for checking whether a number is in particular range?
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