[boost] Re: numeric_cast problem

From: Michael D. Borghardt (michael_at_[hidden])
Date: 2004-01-05 04:55:41

How about this to handle unsigned to signed conversion?

template <>
struct greater_than_type_max<false, false>
{
    template <class X, class Y>
    static inline bool check(X x, Y y_max)
    { return (sizeof(Y) > sizeof(X) ? static_cast<Y>(x) > y_max : x >
static_cast<X>(y_max));}
// { return static_cast<X>(static_cast<Y>(x)) != x; }  // this is the
original line
};

I created the matrix below with test cases and I have tested the following
so far

The orginal line fails tests 6-9,17,19,20,26,33,34,36,37,39,40 where each
uses the sources MAX value

columns represent the source and the rows represent the target

        char unsigned char signed char short unsigned short signed short int
unsigned int signed int long unsigned long signed long float double
      char   33 PASS 15 17 21 27 34 41
      unsigned char   12 13 18 22 28 35 42
      signed char   6   16 19 23 29 36 43 1,2
      short   PASS PASS   20 PASS 30 37 44
      unsigned short PASS PASS 10   24 31 38 45    25
      signed short   PASS PASS PASS 9   32 39 46
      int   PASS PASS PASS PASS PASS   40 PASS      5
      unsigned int   PASS PASS PASS PASS PASS 11   14
      signed int   PASS PASS PASS PASS PASS PASS 7
      long   PASS PASS PASS PASS PASS PASS PASS PASS
      unsigned long PASS PASS PASS PASS PASS PASS PASS PASS 3,4
      signed long   PASS PASS PASS PASS PASS PASS PASS PASS PASS 8
      float   PASS PASS PASS PASS PASS PASS PASS PASS PASS 26
      double   PASS PASS PASS PASS PASS PASS PASS PASS PASS PASS