You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 

585 lines
18 KiB

/* /////////////////////////////////////////////////////////////////////////
* File: stlsoft/conversion/truncation_test.hpp
*
* Purpose: Runtime checking for numeric conversions.
*
* Created: 10th August 2006
* Updated: 24th November 2011
*
* Home: http://stlsoft.org/
*
* Copyright (c) 2006-2011, Matthew Wilson and Synesis Software
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of
* any contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* ////////////////////////////////////////////////////////////////////// */
/** \file stlsoft/conversion/truncation_test.hpp
*
* \brief [C++ only] Definition of the stlsoft::truncation_test functions
* (\ref group__library__conversion "Conversion" Library).
*/
#ifndef STLSOFT_INCL_STLSOFT_CONVERSION_HPP_TRUNCATION_TEST
#define STLSOFT_INCL_STLSOFT_CONVERSION_HPP_TRUNCATION_TEST
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_TRUNCATION_TEST_MAJOR 1
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_TRUNCATION_TEST_MINOR 0
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_TRUNCATION_TEST_REVISION 6
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_TRUNCATION_TEST_EDIT 48
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/* /////////////////////////////////////////////////////////////////////////
* Auto-generation and compatibility
*/
/*
*/
/* /////////////////////////////////////////////////////////////////////////
* Includes
*/
#ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT
# include <stlsoft/stlsoft.h>
#endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */
#ifndef STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS
# include <stlsoft/util/limit_traits.h>
#endif /* !STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS */
#ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_SIGN_TRAITS
# include <stlsoft/util/sign_traits.hpp>
#endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_SIGN_TRAITS */
#ifndef STLSOFT_INCL_STLSOFT_META_HPP_IS_INTEGRAL_TYPE
# include <stlsoft/meta/is_integral_type.hpp>
#endif /* !STLSOFT_INCL_STLSOFT_META_HPP_IS_INTEGRAL_TYPE */
#ifndef STLSOFT_INCL_STLSOFT_META_HPP_IS_SIGNED_TYPE
# include <stlsoft/meta/is_signed_type.hpp>
#endif /* !STLSOFT_INCL_STLSOFT_META_HPP_IS_SIGNED_TYPE */
#ifdef STLSOFT_UNITTEST
# include <limits.h>
#endif /* STLSOFT_UNITTEST */
#if defined(STLSOFT_UNITTEST) || \
defined(_DEBUG)
# include <typeinfo>
# if defined(STLSOFT_COMPILER_IS_MSVC)
# include <crtdbg.h>
# endif /* VC++ */
#endif /* STLSOFT_UNITTEST || _DEBUG */
/* /////////////////////////////////////////////////////////////////////////
* Namespace
*/
#ifndef _STLSOFT_NO_NAMESPACE
namespace stlsoft
{
#endif /* _STLSOFT_NO_NAMESPACE */
/* /////////////////////////////////////////////////////////////////////////
* Functions
*
*
* Assume 11 types:
* char, signed char, unsigned char
* short, unsigned short
* int, unsigned int
* long, unsigned long
* long long, unsigned long long
*
* That gives 121 permutations:
* (a) 11 where the type is the same
* (b) 20 where the sign is the same and sizeof(FROM) <= sizeof(TO); superset of (a)
* (c) 10 where FROM is unsigned and sizeof(FROM) < sizeof(TO)
* (d) 80 that must be determined dynamically
*
*
* The strategy is as follows:
*
if( signof(FROM) == signof(TO) && // Compile-time test 1
sizeof(FROM) <= sizeof(TO))
{
return true;
}
else if(unsigned == signof(FROM) && // Compile-time test 2
sizeof(FROM) < sizeof(TO))
{
return true;
}
else
{
return runtime_test<TO>(from);
}
*
* The runtime test evaluates to the following:
*
* If the FROM type is signed, then
*/
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
// The permutations are:
//
// 1a FROM signed | TO signed | sizeof(FROM) < sizeof(TO) => Always yes
// 1b FROM signed | TO signed | sizeof(FROM) = sizeof(TO) => Always yes
// 1c FROM signed | TO signed | sizeof(FROM) > sizeof(TO) => Runtime test
//
// 2a FROM unsigned | TO signed | sizeof(FROM) < sizeof(TO) => Always yes
// 2b FROM unsigned | TO signed | sizeof(FROM) = sizeof(TO) => Runtime test
// 2c FROM unsigned | TO signed | sizeof(FROM) > sizeof(TO) => Runtime test
//
// 3a FROM signed | TO unsigned | sizeof(FROM) < sizeof(TO) => Runtime test
// 3b FROM signed | TO unsigned | sizeof(FROM) = sizeof(TO) => Runtime test
// 3c FROM signed | TO unsigned | sizeof(FROM) > sizeof(TO) => Runtime test
//
// 4a FROM unsigned | TO unsigned | sizeof(FROM) < sizeof(TO) => Always yes
// 4b FROM unsigned | TO unsigned | sizeof(FROM) = sizeof(TO) => Always yes
// 4c FROM unsigned | TO unsigned | sizeof(FROM) > sizeof(TO) => Runtime test
template< ss_typename_param_k TO
, ss_typename_param_k FROM
>
inline bool truncation_test_helper_runtime_test_different_sign_FROM_is_signed(FROM from, yes_type, TO)
{
#ifdef _DEBUG
# if defined(STLSOFT_COMPILER_IS_MSVC)
int const flags = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
_CrtSetDbgFlag(flags & ~(_CRTDBG_ALLOC_MEM_DF));
# endif /* VC++ */
char const* TO_ = typeid(TO).name();
char const* FROM_ = typeid(FROM).name();
STLSOFT_SUPPRESS_UNUSED(TO_);
STLSOFT_SUPPRESS_UNUSED(FROM_);
# if defined(STLSOFT_COMPILER_IS_MSVC)
_CrtSetDbgFlag(flags);
# endif /* VC++ */
#endif /* _DEBUG */
enum { TO_is_signed = is_signed_type<TO>::value };
enum { FROM_is_signed = is_signed_type<FROM>::value };
const ss_size_t sizeofFROM = sizeof(FROM);
const ss_size_t sizeofTO = sizeof(TO);
STLSOFT_SUPPRESS_UNUSED(sizeofFROM);
STLSOFT_SUPPRESS_UNUSED(sizeofTO);
STLSOFT_STATIC_ASSERT((0 == int(TO_is_signed)) != (0 == int(FROM_is_signed)));
STLSOFT_STATIC_ASSERT(0 != int(FROM_is_signed));
STLSOFT_STATIC_ASSERT(0 == int(TO_is_signed));
// FROM is signed
// TO is unsigned
//
// Truncation occurs if:
//
// - from < 0
// - from > toMax
// - from
if(from < 0)
{
return false;
}
else if(sizeofFROM < sizeofTO) // 3a
{
return true;
}
else
{
if(sizeofFROM == sizeofTO)
{
TO toMax = limit_traits<TO>::maximum();
if(toMax < static_cast<TO>(from))
{
return false;
}
else
{
return true;
}
}
else // 3b & 3c
{
FROM toMax = static_cast<FROM>(limit_traits<TO>::maximum());
if(from > toMax)
{
return false;
}
else
{
return true;
}
}
}
}
template< ss_typename_param_k TO
, ss_typename_param_k FROM
>
inline bool truncation_test_helper_runtime_test_different_sign_FROM_is_signed(FROM from, no_type, TO)
{
#ifdef _DEBUG
# if defined(STLSOFT_COMPILER_IS_MSVC)
int const flags = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
_CrtSetDbgFlag(flags & ~(_CRTDBG_ALLOC_MEM_DF));
# endif /* VC++ */
char const* TO_ = typeid(TO).name();
char const* FROM_ = typeid(FROM).name();
STLSOFT_SUPPRESS_UNUSED(TO_);
STLSOFT_SUPPRESS_UNUSED(FROM_);
# if defined(STLSOFT_COMPILER_IS_MSVC)
_CrtSetDbgFlag(flags);
# endif /* VC++ */
#endif /* _DEBUG */
enum { TO_is_signed = is_signed_type<TO>::value };
enum { FROM_is_signed = is_signed_type<FROM>::value };
const ss_size_t sizeofFROM = sizeof(FROM);
const ss_size_t sizeofTO = sizeof(TO);
STLSOFT_SUPPRESS_UNUSED(sizeofFROM);
STLSOFT_SUPPRESS_UNUSED(sizeofTO);
STLSOFT_STATIC_ASSERT((0 == int(TO_is_signed)) != (0 == int(FROM_is_signed)));
STLSOFT_STATIC_ASSERT(0 == int(FROM_is_signed));
STLSOFT_STATIC_ASSERT(0 != int(TO_is_signed));
// FROM is unsigned
// TO is signed
//
// Truncation occurs if from > toMax
FROM toMax = static_cast<FROM>(limit_traits<TO>::maximum());
if(from > toMax)
{
return false;
}
else
{
return true;
}
}
template< ss_typename_param_k TO
, ss_typename_param_k FROM
>
inline bool truncation_test_helper_runtime_test_same_sign(FROM from, yes_type, TO) // The use of the dummy variable is to fix a bug with VC++ 5-7.0
{
#ifdef _DEBUG
# if defined(STLSOFT_COMPILER_IS_MSVC)
int const flags = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
_CrtSetDbgFlag(flags & ~(_CRTDBG_ALLOC_MEM_DF));
# endif /* VC++ */
char const* TO_ = typeid(TO).name();
char const* FROM_ = typeid(FROM).name();
STLSOFT_SUPPRESS_UNUSED(TO_);
STLSOFT_SUPPRESS_UNUSED(FROM_);
# if defined(STLSOFT_COMPILER_IS_MSVC)
_CrtSetDbgFlag(flags);
# endif /* VC++ */
#endif /* _DEBUG */
const ss_size_t sizeofFROM = sizeof(FROM);
const ss_size_t sizeofTO = sizeof(TO);
STLSOFT_STATIC_ASSERT(sizeofTO < sizeofFROM);
// This is a fully runtime test: does FROM fit into TO's limits?
//
// To do this we elicit TO's min and max. The values are held in
// FROM, which involves no truncation because sizeof(FROM) > sizeof(TO)
FROM toMax = static_cast<FROM>(limit_traits<TO>::maximum());
FROM toMin = static_cast<FROM>(limit_traits<TO>::minimum());
if( from < toMin ||
from > toMax)
{
return false;
}
else
{
return true;
}
}
template< ss_typename_param_k TO
, ss_typename_param_k FROM
>
inline bool truncation_test_helper_runtime_test_same_sign(FROM from, no_type, TO)
{
#ifdef _DEBUG
# if defined(STLSOFT_COMPILER_IS_MSVC)
int const flags = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
_CrtSetDbgFlag(flags & ~(_CRTDBG_ALLOC_MEM_DF));
# endif /* VC++ */
char const* TO_ = typeid(TO).name();
char const* FROM_ = typeid(FROM).name();
STLSOFT_SUPPRESS_UNUSED(TO_);
STLSOFT_SUPPRESS_UNUSED(FROM_);
# if defined(STLSOFT_COMPILER_IS_MSVC)
_CrtSetDbgFlag(flags);
# endif /* VC++ */
#endif /* _DEBUG */
enum { TO_is_signed = is_signed_type<TO>::value };
enum { FROM_is_signed = is_signed_type<FROM>::value };
const ss_size_t sizeofFROM = sizeof(FROM);
const ss_size_t sizeofTO = sizeof(TO);
STLSOFT_SUPPRESS_UNUSED(sizeofFROM);
STLSOFT_SUPPRESS_UNUSED(sizeofTO);
STLSOFT_STATIC_ASSERT((0 == int(TO_is_signed)) != (0 == int(FROM_is_signed)));
typedef ss_typename_param_k value_to_yesno_type<FROM_is_signed>::type same_sign_yesno_t;
return truncation_test_helper_runtime_test_different_sign_FROM_is_signed<TO>(from, same_sign_yesno_t(), TO());
}
template< ss_typename_param_k TO
, ss_typename_param_k FROM
>
inline bool truncation_test_helper_runtime_test(FROM from, no_type, TO ) // The use of the dummy variable is to fix a bug with VC++ 5-7.0
{
#ifdef _DEBUG
# if defined(STLSOFT_COMPILER_IS_MSVC)
int const flags = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
_CrtSetDbgFlag(flags & ~(_CRTDBG_ALLOC_MEM_DF));
# endif /* VC++ */
char const* TO_ = typeid(TO).name();
char const* FROM_ = typeid(FROM).name();
STLSOFT_SUPPRESS_UNUSED(TO_);
STLSOFT_SUPPRESS_UNUSED(FROM_);
# if defined(STLSOFT_COMPILER_IS_MSVC)
_CrtSetDbgFlag(flags);
# endif /* VC++ */
#endif /* _DEBUG */
// Types are different
// Next test for same sign
enum { TO_is_signed = is_signed_type<TO>::value };
enum { FROM_is_signed = is_signed_type<FROM>::value };
enum { types_have_same_sign = int(TO_is_signed) == int(FROM_is_signed) };
const ss_size_t sizeofFROM = sizeof(FROM);
const ss_size_t sizeofTO = sizeof(TO);
STLSOFT_STATIC_ASSERT(sizeofFROM >= sizeofTO || FROM_is_signed);
typedef ss_typename_param_k value_to_yesno_type<types_have_same_sign>::type same_sign_yesno_t;
return truncation_test_helper_runtime_test_same_sign<TO>(from, same_sign_yesno_t(), TO());
}
template <typename T>
inline bool truncation_test_helper_runtime_test(T, yes_type, ...)
{
return true;
}
template< ss_typename_param_k TO
, ss_typename_param_k FROM
>
inline bool truncation_test_(FROM from, TO dummy = TO()) // The use of the dummy variable is to fix a bug with VC++ 5-7.0
{
#ifdef _DEBUG
# if defined(STLSOFT_COMPILER_IS_MSVC)
int const flags = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
_CrtSetDbgFlag(flags & ~(_CRTDBG_ALLOC_MEM_DF));
# endif /* VC++ */
char const* TO_ = typeid(TO).name();
char const* FROM_ = typeid(FROM).name();
STLSOFT_SUPPRESS_UNUSED(TO_);
STLSOFT_SUPPRESS_UNUSED(FROM_);
# if defined(STLSOFT_COMPILER_IS_MSVC)
_CrtSetDbgFlag(flags);
# endif /* VC++ */
#endif /* _DEBUG */
// First, we must check that the types are compatible, with constraints
// Both types must be integral
STLSOFT_STATIC_ASSERT(0 != is_integral_type<TO>::value);
STLSOFT_STATIC_ASSERT(0 != is_integral_type<FROM>::value);
// Now calculate the sizes
const ss_size_t sizeofFROM = sizeof(FROM);
const ss_size_t sizeofTO = sizeof(TO);
// Now determine the signs
enum { TO_is_signed = is_signed_type<TO>::value };
enum { FROM_is_signed = is_signed_type<FROM>::value };
// We know at compile time that FROM fits into TO if:
//
// - they have the same sign, and sizeof(FROM) <= sizeof(TO), OR
// - FROM is unsigned (and TO is signed), and sizeof(FROM) < sizeof(TO)
//
// If either of these hold, then the answer is true: the yes_type overload
// of truncation_test_helper_runtime_test() is selected.
//
// If not, then a runtime test is required: the no_type overload
// of truncation_test_helper_runtime_test() is selected.
enum { types_are_statically_compatible =
( int(TO_is_signed) == int(FROM_is_signed) &&
sizeofFROM <= sizeofTO)
||
( !FROM_is_signed &&
sizeofFROM < sizeofTO) };
typedef ss_typename_param_k value_to_yesno_type<types_are_statically_compatible>::type yesno_t;
# if defined(STLSOFT_COMPILER_IS_MSVC) && \
defined(_Wp64) && \
!defined(_WIN64)
# pragma warning(push)
# pragma warning(disable : 4267)
# endif /* VC++ + Win32 + _Wp32 */
return truncation_test_helper_runtime_test<TO>(from, yesno_t(), dummy);
# if defined(STLSOFT_COMPILER_IS_MSVC) && \
defined(_Wp64) && \
!defined(_WIN64)
# pragma warning(pop)
# endif /* VC++ + Win32 + _Wp32 */
}
#if 0
template<ss_typename_param_k TO>
class truncation_test
{
public:
template <ss_typename_param_k FROM>
truncation_test(FROM from)
: m_b(truncation_test_(from, get_to_()))
{}
public:
operator bool () const
{
return m_b;
}
private:
static TO get_to_()
{
return TO();
}
private:
const bool m_b;
};
#else /* ? 0 */
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/** Indicates whether a given value can be cast to a given type without
* truncation
*
* \ingroup group__library__conversion
*
* Example:
<pre>
truncation_cast&lt;unsigned>(-1); // Will return false, since negatives cannot fit in unsigned
truncation_cast&lt;short>(30000); // Will return true, since 30000 will fit inside short (assuming short has >= 16-bits)
</pre>
*
* \param from The value to be tested
*
* \retval false The value will experience truncation
* \retval true The value will not be truncated
*/
template< ss_typename_param_k TO
, ss_typename_param_k FROM
>
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
inline bool truncation_test(FROM from, TO dummy = TO()) // The use of the dummy variable is to fix a bug with VC++ 5-7.0
#else /* ? STLSOFT_DOCUMENTATION_SKIP_SECTION */
inline bool truncation_test(FROM from)
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
{
return truncation_test_(from, dummy);
}
#endif /* 0 */
////////////////////////////////////////////////////////////////////////////
// Unit-testing
#ifdef STLSOFT_UNITTEST
# include "./unittest/truncation_test_unittest_.h"
#endif /* STLSOFT_UNITTEST */
/* ////////////////////////////////////////////////////////////////////// */
#ifndef _STLSOFT_NO_NAMESPACE
} // namespace stlsoft
#endif /* _STLSOFT_NO_NAMESPACE */
/* ////////////////////////////////////////////////////////////////////// */
#endif /* !STLSOFT_INCL_STLSOFT_CONVERSION_HPP_TRUNCATION_TEST */
/* ///////////////////////////// end of file //////////////////////////// */