Re: [Boost-bugs] [Boost C++ Libraries] #819: uniform_int<> with type's maximum availaible range error

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #819: uniform_int<> with type's maximum availaible range error
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2008-02-09 01:13:05

#819: uniform_int<> with type's maximum availaible range error
---------------------+------------------------------------------------------
  Reporter:  nobody  |       Owner:  no-maintainer
      Type:  Bugs    |      Status:  new          
 Milestone:          |   Component:  random       
   Version:  None    |    Severity:  Problem      
Resolution:  None    |    Keywords:               
---------------------+------------------------------------------------------
Changes (by marshall):

  * owner:  jmaurer => no-maintainer
  * status:  assigned => new
  * severity:  => Problem

Old description:

> {{{
> using boost 1_33_1, MSVC 8.0
> using namespace boost;
> using namespace std;
>
> typedef int32_t IntType;// the same bug for int8_t int16_t int64_t
>
> uniform_int<IntType> ui(numeric_limits<IntType>::min(),
> numeric_limits<IntType>::max());
> rand48 rng;
> variate_generator<rand48, uniform_int<int32_t> > gen(rng, ui);
> IntType x = gen();  // infinite loop here
> If we makes range smaller or if we using unsigned types - everything is
> OK
> So if we will look to  uniform_int.hpp we will see.....
> template<class IntType = int>
> class uniform_int
> {
> public:
> ....
>   typedef IntType result_type;
> ....
>   explicit uniform_int(IntType min = 0, IntType max = 9)
>     : _min(min), _max(max)
>   {
> ......
>     assert(min <= max);     init();
>   }.....
> private:
>   result_type _min, _max, _range;
>   void init()
>   {
>     _range = _max - _min;// for SIGNED types and maximum available range
> we will receive..... of course -1 !!!!!!  }
> ......}Also i want to draw the attention russian-speaking boost
> developers to the http://rsdn.ru/Forum/Message.aspx?mid=2252961&only=1

> }}}

New description:

 {{{
 using boost 1_33_1, MSVC 8.0
 using namespace boost;
 using namespace std;

 typedef int32_t IntType;// the same bug for int8_t int16_t int64_t

 uniform_int<IntType> ui(numeric_limits<IntType>::min(),
 numeric_limits<IntType>::max());
 rand48 rng;
 variate_generator<rand48, uniform_int<int32_t> > gen(rng, ui);
 IntType x = gen();  // infinite loop here
 If we makes range smaller or if we using unsigned types - everything is OK
 So if we will look to  uniform_int.hpp we will see.....
 template<class IntType = int>
 class uniform_int
 {
 public:
 ....
   typedef IntType result_type;
 ....
   explicit uniform_int(IntType min = 0, IntType max = 9)
     : _min(min), _max(max)
   {
 ......
     assert(min <= max);     init();
   }.....
 private:
   result_type _min, _max, _range;
   void init()
   {
     _range = _max - _min;// for SIGNED types and maximum available range
 we will receive..... of course -1 !!!!!!  }
 ......}Also i want to draw the attention russian-speaking boost developers
 to the http://rsdn.ru/Forum/Message.aspx?mid=2252961&only=1

 }}}

-- 
Ticket URL: <http://svn.boost.org/trac/boost/ticket/819#comment:1>
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