[boost] Re: numeric_cast problem

From: Michael D. Borghardt (michael_at_[hidden])
Date: 2004-01-05 19:28:13

I assumed you wanted text

                           Testing Cases
     c     uc  sc    s    us   ss     i      ui    si     l     ul     sl
f     d
c   N   33   P   15  17   21   27   34   41   47  55   65
uc       N   12  13  18   22   28   35   42   48   56   66
sc        6   N   16  19   23   29   36   43   1,2  57   67
s         P    P    N  20   P     30   37   44   49   58   68
us       P    P    10  N   24   31   38   45   50   59   69   25
ss       P    P     P    9   N    32   39   46   51   60   70
i         P    P     P    P   P    N    40   P     52    61   71          5
ui       P    P     P    P   P    11   N   14    53     62   72
si       P    P     P    P   P    P     7    N     54     63   73
l         P    P     P    P   P    P    P    P     N       64   P
ul       P    P     P    P   P    P    P    P    3,4,75  N   74
sl       P    P     P    P   P    P    P    P    P           8   N
f        P    P     P    P   P    P    P    P    P         26    P   N
d       P    P     P    P   P    P    P    P    P         P      P   P    N

columns are source
rows are targer

N   Not applicable since converting to itself
P    Pass - I have not checked all these

c     char
uc   unsigned char
sc    signed char
s     short
us    unsigned short
ss    signed short
i      int
ui    unsigned int
si    signed int
l      long
ul    unsigned long
sl    signed long
f     float
d    double

Tests  6 -9,15 -23, 26 - 73 use sources MAX value
Here is my latest table with the following changes

Test 10 -14,24,74, 75 use sources MIN value

Test 25 uses 500.5

Tests  52,53,54,62,71,72,73 are not tested as they have the same size on my
platform

The orginal source line fails tests
6-9,17,19,20,26,33,34,36,37,39,40,55,57,58,60,61,63,64 where each
uses the sources MAX value

====> new lines

template <>
struct greater_than_type_max<false, true>
{
    template <class X, class Y>
    static inline bool check(X x, Y y_max)
    {
        return x >=0
        // && static_cast<X>(static_cast<Y>(x)) != x; } // orignal line
===>               && ((static_cast<X>(static_cast<Y>(x)) != x)
===>                      || (sizeof(Y) >= sizeof(X) ? static_cast<Y>(x) >
y_max : x > static_cast<X>(y_max)));
    }
    # if defined(BOOST_MSVC) && BOOST_MSVC <= 1200
// MSVC6 can't static_cast unsigned __int64 -> floating types
# define BOOST_UINT64_CAST(src_type) \
    static inline bool check(src_type x, unsigned __int64) \
    { \
        if (x < 0) return false; \
        unsigned __int64 y = static_cast<unsigned __int64>(x); \
        bool odd = y & 0x1; \
        __int64 div2 = static_cast<__int64>(y >> 1); \
        return ((static_cast<src_type>(div2) * 2.0) + odd) != x; \
    }
    BOOST_UINT64_CAST(long double);
    BOOST_UINT64_CAST(double);
    BOOST_UINT64_CAST(float);
# undef BOOST_UINT64_CAST
# endif
};

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;  // orignal line
    };

With my changes they all the ones that pass still pass and the ones that
failed now pass.