simple_number.h
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00023 #ifndef _KJS_SIMPLE_NUMBER_H_
00024 #define _KJS_SIMPLE_NUMBER_H_
00025 
00026 #include <limits.h>
00027 #include <math.h>
00028 #include <string.h>
00029 
00030 #define IS_NEGATIVE_ZERO(num) (num == 0.0 && !memcmp(&num,&SimpleNumber::negZero,sizeof(double)))
00031 
00032 namespace KJS {
00033     class ValueImp;
00034 
00035     class SimpleNumber {
00036     public:
00037     enum { tag = 1, shift = 2, mask = (1 << shift) - 1, sign = 1L << (sizeof(long) * 8 - 1 ), max = (1L << ((sizeof(long) * 8 - 1) - shift)) - 1, min = -max - 1, imax = (1L << ((sizeof(int) * 8 - 1) - shift)) - 1, imin = -imax - 1 };
00038 
00039     static inline bool is(const ValueImp *imp) { return ((long)imp & mask) == tag; }
00040     static inline long value(const ValueImp *imp) { return ((long)imp >> shift) | (((long)imp & sign) ? ~max : 0); }
00041 
00042     static inline bool fits(int i) { return i <= imax && i >= imin; }
00043     static inline bool fits(unsigned i) { return i <= (unsigned)max; }
00044     static inline bool fits(long i) { return i <= max && i >= min; }
00045     static inline bool fits(unsigned long i) { return i <= (unsigned)max; }
00046     static inline bool fits(double d) { return d <= max && d >= min && d == (double)(long)d &&
00047                         !IS_NEGATIVE_ZERO(d); }
00048     static inline ValueImp *make(long i) { return (ValueImp *)((i << shift) | tag); }
00049 
00050     static double negZero;
00051 
00052     };
00053 }
00054 
00055 #endif
 
This file is part of the documentation for kjs Library Version 3.2.0.