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7 Commits
| Author | SHA1 | Date | |
|---|---|---|---|
 Daniel James
|
878cd7bb2a | ||
|
Daniel James
|
ccd33cb77d | ||
|
Daniel James
|
a3eb0b8470 | ||
|
Marshall Clow
|
6dc956e342 | ||
|
John Maddock
|
2994de17ef | ||
|
Matias Capeletto
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9487756e4b | ||
|
Matias Capeletto
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35a5859da6 |
@@ -0,0 +1,30 @@
|
||||
# Boost.Numeric/Conversion
|
||||
#
|
||||
# Copyright (c) 2004-2007 Fernando Luis Cacciola Carballal
|
||||
#
|
||||
# Distributed under the Boost Software License, Version 1.0.
|
||||
# (See accompanying file LICENSE_1_0.txt or copy at
|
||||
# http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
|
||||
# Quickbook
|
||||
# -----------------------------------------------------------------------------
|
||||
|
||||
import quickbook ;
|
||||
|
||||
xml conversion
|
||||
:
|
||||
conversion.qbk
|
||||
;
|
||||
|
||||
boostbook standalone
|
||||
:
|
||||
conversion
|
||||
:
|
||||
<xsl:param>boost.root=../../../../..
|
||||
<xsl:param>boost.libraries=../../../../libraries.htm
|
||||
<xsl:param>toc.max.depth=2
|
||||
<xsl:param>toc.section.depth=2
|
||||
<xsl:param>chunk.section.depth=1
|
||||
;
|
||||
|
||||
-109
@@ -1,109 +0,0 @@
|
||||
<HTML>
|
||||
<HEAD>
|
||||
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
|
||||
<LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css">
|
||||
<TITLE>Boost Numeric Conversion Library - Bounds</TITLE>
|
||||
</HEAD>
|
||||
<BODY BGCOLOR="#FFFFFF" TEXT="#000000">
|
||||
<TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%"
|
||||
SUMMARY="header">
|
||||
<TR>
|
||||
<TH VALIGN="top" WIDTH="300">
|
||||
<H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277"
|
||||
ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH>
|
||||
<TH VALIGN="top">
|
||||
<H1 ALIGN="center">Boost Numeric Conversion Library</H1>
|
||||
|
||||
<H1><A HREF="http://www.boost.org">Header </A><A
|
||||
HREF="../../../../boost/numeric/conversion/bounds.hpp">boost/numeric/conversion/bounds.hpp</A></H1>
|
||||
</TH>
|
||||
</TR>
|
||||
</TABLE><HR>
|
||||
<H2>Contents</H2>
|
||||
<UL>
|
||||
<LI><A HREF="#introduction">Introduction</A></LI>
|
||||
<LI><A HREF="#bounds"><code>template class bounds<N></CODE></A></LI>
|
||||
<LI><A HREF="#examples">Examples</A></LI>
|
||||
<!--<LI><A HREF="#implementation">Implementation</A></LI>-->
|
||||
<!--<LI><A HREF="#portability">Portability</A></LI>-->
|
||||
</UL> <HR>
|
||||
<H2><A NAME="introduction">Introduction</A></H2>
|
||||
<P>To determine the ranges of numeric types with std:: numeric_limits
|
||||
[18.2.1], different syntax have to be used depending on numeric type.
|
||||
Specifically, numeric_limits<T>::min() for integral types returns the
|
||||
minimum finite value, whereas for floating point types it returns the minimum
|
||||
positive normalized value. The difference in semantics makes client code
|
||||
unnecessarily complex and error prone. <BR> <BR>
|
||||
boost::numeric::bounds<> provides a consistent interface for retrieving
|
||||
the maximum finite value, the minimum finite value and the minimum positive
|
||||
normalized value (0 for integral types) for numeric types. The selection of
|
||||
implementation is performed at compile time, so there is no runtime overhead.
|
||||
<BR>
|
||||
<BR> </P> <HR>
|
||||
<H2><A NAME="bounds"><CODE>traits class bounds<N></CODE></A></H2>
|
||||
<BLOCKQUOTE>
|
||||
|
||||
<PRE>template<class N>
|
||||
struct bounds
|
||||
{
|
||||
static N lowest () { return <i>implementation_defined</i>; }
|
||||
static N highest () { return <i>implementation_defined</i>; }
|
||||
static N smallest() { return <i>implementation_defined</i>; }
|
||||
};</PRE>
|
||||
</BLOCKQUOTE>
|
||||
<H3>Members</H3>
|
||||
<PRE>lowest()</PRE>
|
||||
<P>Returns the minimum finite value, equivalent to
|
||||
numeric_limits<T>::min() when T is an integral type, and to
|
||||
-numeric_limits<T>::max() when T is a floating point type. </P>
|
||||
<PRE>highest()</PRE>
|
||||
<P>Returns the maximum finite value, equivalent to
|
||||
numeric_limits<T>::max(). </P>
|
||||
<PRE>smallest()</PRE>
|
||||
|
||||
<P>Returns the smallest positive normalized value for floating point types with
|
||||
denormalization, or returns 0 for integral types. <BR>
|
||||
<BR>
|
||||
</P> <HR>
|
||||
<H2><A NAME="examples">Examples</A></H2>
|
||||
|
||||
<P>The following example demonstrates the use of numeric::bounds<> and the
|
||||
equivalent code using numeric_limits: </P>
|
||||
|
||||
<BLOCKQUOTE>
|
||||
<PRE>#include <iostream>
|
||||
|
||||
#include <boost/numeric/conversion/bounds.hpp>
|
||||
#include <boost/limits.hpp>
|
||||
|
||||
int main() {
|
||||
|
||||
std::cout << "numeric::bounds versus numeric_limits example.\n";
|
||||
|
||||
std::cout << "The maximum value for float:\n";
|
||||
std::cout << boost::numeric::bounds<float>::highest() << "\n";
|
||||
std::cout << std::numeric_limits<float>::max() << "\n";
|
||||
|
||||
std::cout << "The minimum value for float:\n";
|
||||
std::cout << boost::numeric::bounds<float>::lowest() << "\n";
|
||||
std::cout << -std::numeric_limits<float>::max() << "\n";
|
||||
|
||||
std::cout << "The smallest positive value for float:\n";
|
||||
std::cout << boost::numeric::bounds<float>::smallest() << "\n";
|
||||
std::cout << std::numeric_limits<float>::min() << "\n";
|
||||
|
||||
return 0;
|
||||
}</PRE>
|
||||
</BLOCKQUOTE>
|
||||
|
||||
<hr>
|
||||
<P>Back to <A HREF="index.html">Numeric Conversion library index</A></P>
|
||||
<HR>
|
||||
<P>Revised 23 June 2004</P>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</BODY>
|
||||
</HTML>
|
||||
+1
-1
@@ -21,7 +21,7 @@ Distributed under the Boost Software License, Version 1.0.
|
||||
|
||||
[/ Cited Boost resources ]
|
||||
|
||||
[def __MPL_INTEGRAL_CONSTANT__ [@../../../../mpl/refmanual/integral-constant.html MPL's Integral Constant] ]
|
||||
[def __MPL_INTEGRAL_CONSTANT__ [@/libs/mpl/doc/refmanual/integral-constant.html MPL's Integral Constant] ]
|
||||
|
||||
|
||||
|
||||
|
||||
@@ -1,337 +0,0 @@
|
||||
<HTML>
|
||||
<HEAD>
|
||||
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
|
||||
<LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css">
|
||||
<TITLE>Boost Numeric Conversion Library - Conversion Traits</TITLE>
|
||||
</HEAD>
|
||||
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000ff" VLINK="#800080">
|
||||
<TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%"
|
||||
SUMMARY="header">
|
||||
<TR>
|
||||
<TH VALIGN="top" WIDTH="300">
|
||||
<H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277"
|
||||
ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH>
|
||||
<TH VALIGN="top">
|
||||
<H1 ALIGN="center">Boost Numeric Conversion Library</H1>
|
||||
|
||||
<H1><A HREF="http://www.boost.org">Header </A><A
|
||||
HREF="../../../../boost/numeric/conversion/conversion_traits.hpp">boost/numeric/conversion/conversion_traits.hpp</A></H1>
|
||||
</TH>
|
||||
</TR>
|
||||
</TABLE> <HR>
|
||||
<H2>Contents</H2>
|
||||
<DL CLASS="page-index">
|
||||
<DT><A HREF="#types">Types</A></DT>
|
||||
</DL>
|
||||
<UL>
|
||||
|
||||
<LI><A HREF="#ncm"><CODE>enumeration boost::numeric::int_float_mixture_enum;</CODE></A></LI>
|
||||
<LI><A HREF="#ncsm"><CODE>enumeration boost::numeric::sign_mixture_enum;</CODE></A></LI>
|
||||
<LI><A HREF="#ncum"><CODE>enumeration boost::numeric::udt_builtin_mixture_enum;</CODE></A></LI>
|
||||
<LI><A HREF="#ifm"><CODE>template class boost::numeric::int_float_mixture<T,S></CODE></A></LI>
|
||||
<LI><A HREF="#sm"><CODE>template class boost::numeric::sign_mixture<T,S></CODE></A></LI>
|
||||
<LI><A HREF="#ubm"><CODE>template class boost::numeric::udt_builtin_mixture<T,S></CODE></A></LI>
|
||||
<LI><A HREF="#isr"><CODE>template class boost::numeric::is_subranged<T,S></CODE></A></LI>
|
||||
<LI><A HREF="#nct"><CODE>template class boost::numeric::conversion_traits<T,S></CODE></A></LI>
|
||||
</UL>
|
||||
<DL><DT><A HREF="#examples">Example(s)</A></DT></DL>
|
||||
<HR>
|
||||
|
||||
<H2><A NAME="types"></A>Types</H2>
|
||||
|
||||
<H2><CODE><A NAME="ncm">enumeration int_float_mixture</A>_enum</CODE></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
enum int_float_mixture_enum
|
||||
{
|
||||
integral_to_integral
|
||||
,integral_to_float
|
||||
,float_to_integral
|
||||
,float_to_float
|
||||
} ;
|
||||
|
||||
} } // namespace boost::numeric
|
||||
</PRE>
|
||||
|
||||
<H2><CODE><A NAME="ncsm">enumeration sign_mixture</A>_enum</CODE></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
enum sign_mixture_enum
|
||||
{
|
||||
unsigned_to_unsigned
|
||||
,signed_to_signed
|
||||
,signed_to_unsigned
|
||||
,unsigned_to_signed
|
||||
} ;
|
||||
|
||||
} } // namespace boost::numeric</PRE>
|
||||
|
||||
<H2><CODE><A NAME="ncum">enumeration udt_builtin_mixture</A>_enum</CODE></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
enum udt_builtin_mixture_enum
|
||||
{
|
||||
builtin_to_builtin
|
||||
,builtin_to_udt
|
||||
,udt_to_builtin
|
||||
,udt_to_udt
|
||||
} ;
|
||||
|
||||
} } // namespace boost::numeric</PRE>
|
||||
|
||||
<hr>
|
||||
|
||||
<H2><A NAME="ifm"><CODE>template class int_float_mixture<></CODE></A></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
template <class T, class S>
|
||||
struct int_float_mixture : mpl::integral_c<int_float_mixture_enum, <i>impl-def-value</i>> {} ;
|
||||
|
||||
} } // namespace boost::numeric
|
||||
</PRE>
|
||||
<p>Classifying <code>S</code> and <code>T</code> as either <code>integral</code>
|
||||
or <code>float</code>, this <a href="../../../mpl/doc/refmanual/integral-constant.html">MPL's Integral Constant</a>
|
||||
indicates the combination of these attributes. <br>
|
||||
Its <code>::value</code> is of enumeration type <A HREF="#ncm"><CODE>boost::numeric::int_float_mixture_enum</CODE></A>
|
||||
</p>
|
||||
|
||||
<hr>
|
||||
|
||||
<H2><A NAME="sm"><CODE>template class sign_mixture<></CODE></A></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
template <class T, class S>
|
||||
struct sign_mixture : mpl::integral_c<sign_mixture_enum, <i>impl-def-value</i>> {} ;
|
||||
|
||||
} } // namespace boost::numeric
|
||||
</PRE>
|
||||
<p>Classifying <code>S</code> and <code>T</code> as either <code>signed</code>
|
||||
or <code>unsigned</code>, this <a href="../../../mpl/doc/refmanual/integral-constant.html">MPL's Integral Constant</a>
|
||||
indicates the combination of these attributes. <br>
|
||||
Its <code>::value</code> is of enumeration type <A HREF="#ncm"><CODE>boost::numeric::sign_mixture_enum</CODE></A>
|
||||
</p>
|
||||
|
||||
<hr>
|
||||
|
||||
<H2><A NAME="ubm"><CODE>template class udt_builtin_mixture<></CODE></A></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
template <class T, class S>
|
||||
struct udt_builtin_mixture : mpl::integral_c<udt_builtin__mixture_enum, <i>impl-def-value</i>> {} ;
|
||||
|
||||
} } // namespace boost::numeric
|
||||
</PRE>
|
||||
<p>Classifying <code>S</code> and <code>T</code> as either <code>user-defined</code>
|
||||
or <code>builtin</code>, this <a href="../../../mpl/doc/refmanual/integral-constant.html">MPL's Integral Constant</a>
|
||||
indicates the combination of these attributes. <br>
|
||||
Its <code>::value</code> is of enumeration type <A HREF="#ncm"><CODE>boost::numeric::udt_builtin_mixture_enum</CODE></A>
|
||||
</p>
|
||||
|
||||
<hr>
|
||||
|
||||
<H2><A NAME="isr"><CODE>template class is_subranged<></CODE></A></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
template <class T, class S>
|
||||
struct is_subranged : mpl::bool_<<i>impl-def-value</i>> {} ;
|
||||
|
||||
} } // namespace boost::numeric
|
||||
</PRE>
|
||||
<p>Indicates if the range of the target type T is a subset of the range of the source type S.
|
||||
That is: if there are some source values which fall out of the Target type's range.<br>
|
||||
It is a boolean <a href="../../../mpl/doc/refmanual/integral-constant.html">MPL's Integral Constant</a>..<br>
|
||||
It does not indicate if
|
||||
a <i>particular</i> conversion is effectively out of range; it indicates that
|
||||
some conversion <i>might be</i> out of range because not all the source values
|
||||
are representable as Target type.</p>
|
||||
|
||||
<hr>
|
||||
|
||||
<H2><A NAME="nct"><CODE>template class conversion_traits<></CODE></A></H2>
|
||||
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
|
||||
template <class T, class S>
|
||||
struct conversion_traits
|
||||
{
|
||||
mpl::integral_c<int_float_mixture_enum , ...> int_float_mixture ;
|
||||
mpl::integral_c<sign_mixture_enum , ...> sign_mixture;
|
||||
mpl::integral_c<udt_builtin_mixture_enum, ...> udt_builtin_mixture ;
|
||||
|
||||
mpl::bool_<...> subranged ;
|
||||
mpl::bool_<...> trivial ;
|
||||
|
||||
typedef T target_type ;
|
||||
typedef S source_type ;
|
||||
typedef ... argument_type ;
|
||||
typedef ... result_type ;
|
||||
typedef ... supertype ;
|
||||
typedef ... subtype ;
|
||||
} ;
|
||||
|
||||
} } // namespace numeric, namespace boost
|
||||
</PRE>
|
||||
<BLOCKQUOTE>
|
||||
|
||||
<P>This traits class indicates some properties of a <i>numeric conversion direction</i>:
|
||||
from a source type <code>S</code> to a target type <code>T</code>. It does not indicate the properties of
|
||||
a <i>specific</i> conversion, but of the conversion <i>direction</i>. See
|
||||
<A href="definitions.html#subranged">Definitions</A> for details.<br>
|
||||
</P>
|
||||
|
||||
<P>The traits class provides the following
|
||||
<a href="../../../mpl/doc/refmanual/integral-constant.html">MPL's Integral Constants</a>
|
||||
of enumeration type. They express the <i>combination</i> of certain attributes of the Source and
|
||||
Target types (thus they are call <i>mixture</i>):</P>
|
||||
<TABLE BORDER="1">
|
||||
<TR>
|
||||
<TD> <CODE><B>int_float_mixture</B></CODE> </TD>
|
||||
|
||||
<TD>
|
||||
<P>Same as given by the traits class <A HREF="#ifm"><CODE>int_float_mixture</CODE></A></P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE><B>sign_mixture</B></CODE> </TD>
|
||||
|
||||
<TD>
|
||||
<P>Same as given by the traits class <A HREF="#sm"><CODE>sign_mixture</CODE></A></P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE><B>udt_builtin_mixture</B></CODE> </TD>
|
||||
|
||||
<TD>
|
||||
<P>Same as given by the traits class <A HREF="#ubm"><CODE>udt_builtin_mixture</CODE></A></P>
|
||||
</TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
|
||||
<P>The traits class provides the following
|
||||
<a href="../../../mpl/doc/refmanual/integral-constant.html">MPL's Integral Constants</a>
|
||||
of boolean type which indicates indirectly the relation between the Source and Target
|
||||
<i>ranges</i>
|
||||
(see <A href="definitions.html#range">Definitions</A> for details).</P>
|
||||
<TABLE BORDER="1">
|
||||
<TR>
|
||||
<TD> <CODE> <B>subranged</B></CODE> </TD>
|
||||
|
||||
<TD>
|
||||
<P>Same as given by <A HREF="#isr"><CODE>is_subranged</CODE></A></P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE> <B>trivial</B></CODE> </TD>
|
||||
|
||||
<TD>
|
||||
<P>Indicates if both Source and Target, <u>without cv-qualifications</u>, are
|
||||
the same type.<br>
|
||||
Its <code>::value</code> is of boolean type.</P>
|
||||
</TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
|
||||
<P>The traits class provides the following types. They are the Source and Target
|
||||
types classified and qualified for different purposes.</P>
|
||||
|
||||
<TABLE BORDER="1" width="720">
|
||||
<TR>
|
||||
<TD> <CODE><B>target_type</B></CODE> </TD>
|
||||
<TD>
|
||||
|
||||
<P>The template parameter <CODE>T</CODE><EM> without cv-qualifications</EM></P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE><B>source_type</B></CODE> </TD>
|
||||
<TD>
|
||||
|
||||
<P>The template parameter <CODE>S</CODE><EM> without cv-qualifications</EM></P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE><B>argument_type</B></CODE> </TD>
|
||||
<TD>
|
||||
<P>This type is either <CODE>source_type</CODE> or <CODE>source_type
|
||||
const&</CODE>. <BR> It represents the <I>optimal</I> argument type for the
|
||||
<A HREF="converter.html">converter</A> member functions.<BR>
|
||||
If <CODE>S</CODE> is a built-in type, this is <CODE>source_type</CODE>,
|
||||
otherwise, this is <CODE>source_type const&</CODE>. </P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE><B>result_type</B></CODE></TD>
|
||||
<TD>
|
||||
<P>This type is either <CODE>target_type</CODE> or <CODE>target_type
|
||||
const&</CODE> <BR> It represents the return type of the
|
||||
<A HREF="converter.html">converter</A> member functions.<BR>
|
||||
If <CODE>T==S</CODE>, it is <CODE>target_type const&</CODE>, otherwise,
|
||||
it is <CODE>target_type</CODE>.</P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
|
||||
<TD height="37"> <CODE><B>supertype</B></CODE></TD>
|
||||
|
||||
<TD height="37">
|
||||
<P>If the conversion is <CODE>subranged</CODE>, it is <CODE>source_type</CODE>,
|
||||
otherwise, it is <CODE>target_type</CODE></P>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE><B>subtype</B></CODE></TD>
|
||||
<TD height="37">
|
||||
<P>If the conversion is <CODE>subranged</CODE>, it is <CODE>target_type</CODE>,
|
||||
otherwise, it is <CODE>source_type</CODE></P>
|
||||
</TD>
|
||||
</TR>
|
||||
</TABLE> </BLOCKQUOTE> <HR>
|
||||
|
||||
<H2><A NAME="examples">Examples</A></H2>
|
||||
<BLOCKQUOTE>
|
||||
<PRE>#include <cassert>
|
||||
#include <typeinfo>
|
||||
#include <boost/numeric/conversion/conversion_traits.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
|
||||
// A trivial conversion.
|
||||
typedef boost::numeric::conversion_traits<short,short> Short2Short_Traits ;
|
||||
assert ( Short2Short_Traits::trivial::value ) ;
|
||||
|
||||
// A subranged conversion.
|
||||
typedef boost::numeric::conversion_traits<double,unsigned int> UInt2Double_Traits ;
|
||||
assert ( UInt2Double_Traits::int_float_mixture::value == boost::numeric::integral_to_float ) ;
|
||||
assert ( UInt2Double_Traits::sign_mixture::value == boost::numeric::unsigned_to_signed ) ;
|
||||
assert ( !UInt2Double_Traits::subranged::value ) ;
|
||||
assert ( typeid(UInt2Double_Traits::supertype) == typeid(double) ) ;
|
||||
assert ( typeid(UInt2Double_Traits::subtype) == typeid(unsigned int) ) ;
|
||||
|
||||
// A doubly subranged conversion.
|
||||
assert ( (boost::numeric::conversion_traits<short, unsigned short>::subranged::value) );
|
||||
assert ( (boost::numeric::conversion_traits<unsigned short, short>::subranged::value) );
|
||||
|
||||
return 0;
|
||||
}
|
||||
</PRE>
|
||||
</BLOCKQUOTE>
|
||||
<HR>
|
||||
<P>Back to <A HREF="index.html">Numeric Conversion library index</A></P>
|
||||
<HR>
|
||||
<P>Revised 16 May 2005</P>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</BODY>
|
||||
</HTML>
|
||||
@@ -1,279 +0,0 @@
|
||||
<HTML>
|
||||
|
||||
<HEAD>
|
||||
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
|
||||
<LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css">
|
||||
<TITLE>Boost Numeric Conversion Library - Policy-based Converter</TITLE>
|
||||
</HEAD>
|
||||
|
||||
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000ff" VLINK="#800080">
|
||||
<TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%"
|
||||
SUMMARY="header">
|
||||
<TR>
|
||||
<TD VALIGN="top" WIDTH="300"> <H3><A HREF="http://www.boost.org"><IMG
|
||||
HEIGHT="86" WIDTH="277" ALT="C++ Boost" SRC="../../../../boost.png"
|
||||
BORDER="0"></A> </H3>
|
||||
</TD>
|
||||
<TD VALIGN="top"> <H1 ALIGN="center">Boost Numeric Conversion Library</H1>
|
||||
<H1><A HREF="http://www.boost.org">Header </A><A
|
||||
HREF="../../../../boost/numeric/conversion/converter.hpp">boost/numeric/conversion/converter.hpp</A></H1>
|
||||
</TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
<HR>
|
||||
<H2>Contents</H2>
|
||||
<DT><A HREF="#synopsis">Synopsis</A></DT>
|
||||
<DT><A HREF="requirements.html">User Defined Types support</A></DT>
|
||||
<DT><A HREF="#rchklogic">Range Checking Logic</A></DT>
|
||||
<DT><A HREF="#examples">Examples</A></DT>
|
||||
|
||||
<HR>
|
||||
<H2><A NAME="synopsis">Synopsis</A></H2>
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
|
||||
template<class T,
|
||||
class S,
|
||||
class Traits, = conversion_traits<T,S>
|
||||
class OverflowHandler = def_overflow_handler,
|
||||
class Float2IntRounder = Trunc< typename Traits::source_type >,
|
||||
class RawConverter = raw_converter<Traits>,
|
||||
class UserRangeChecker = UseInternalRangeChecker
|
||||
>
|
||||
struct converter
|
||||
{
|
||||
typedef Traits traits ;
|
||||
|
||||
typedef typename Traits::source_type source_type ;
|
||||
typedef typename Traits::argument_type argument_type ;
|
||||
typedef typename Traits::result_type result_type ;
|
||||
|
||||
static result_type convert ( argument_type s ) ;
|
||||
|
||||
result_type operator() ( argument_type s ) const ;
|
||||
|
||||
// Internal member functions:
|
||||
|
||||
static range_check_result out_of_range ( argument_type s ) ;
|
||||
static void validate_range ( argument_type s ) ;
|
||||
static result_type low_level_convert ( argument_type s ) ;
|
||||
static source_type nearbyint ( argument_type s ) ;
|
||||
|
||||
} ;
|
||||
|
||||
} } // namespace numeric, boost
|
||||
</PRE>
|
||||
|
||||
<P><code>boost::numeric::converter<></code> is a
|
||||
<a href="http://www.sgi.com/tech/stl/UnaryFunction.html">Unary Function Object</a>
|
||||
encapsulating the code to perform a numeric conversion with the direction and properties specified
|
||||
by the <CODE>Traits</CODE> template parameter. It can optionally take some
|
||||
<A HREF="converter_policies.html">policies</a>
|
||||
which can be used to customize its behavior. The Traits parameter is not a policy but
|
||||
the parameter that defines the conversion.
|
||||
</P>
|
||||
<hr>
|
||||
<h2>Template parameters:</h2>
|
||||
<TABLE BORDER="1">
|
||||
<TR>
|
||||
<TD> T</TD>
|
||||
<TD> The <A HREF="definitions.html#numtypes">Numeric Type</A> which is
|
||||
the <i>Target</i> of the conversion.</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> S</TD>
|
||||
<TD> The <A HREF="definitions.html#numtypes">Numeric Type</A> which is
|
||||
the <i>Source</i> of the conversion.</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <CODE>Traits</CODE> </TD>
|
||||
<TD> This must be a conversion traits class with the interface of
|
||||
<A HREF="conversion_traits.html">boost::numeric::conversion_traits</A>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <A HREF="converter_policies.html#oh"><CODE>OverflowHandler</CODE></A> </TD>
|
||||
<TD> <B>Stateless Policy</B> called to administrate the result of the
|
||||
range checking.<br>
|
||||
It is a <b>Function Object</b> which receives the result of <CODE>out_of_range()</CODE>
|
||||
and is called inside the <CODE>validate_range()</CODE> static member function
|
||||
exposed by the converter.</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <A HREF="converter_policies.html#f2i"><CODE>Float2IntRounder</CODE></A> </TD>
|
||||
<TD> <B>Stateless Policy</B> which specifies the rounding mode used for
|
||||
float to integral conversions.<br>
|
||||
It supplies the <CODE>nearbyint()</CODE> static member function exposed
|
||||
by the converter.</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <A HREF="converter_policies.html#rawc"><CODE>RawConverter</CODE></A> </TD>
|
||||
<TD> <B>Stateless Policy</B> which is used to perform the actual conversion.
|
||||
<br>
|
||||
It supplies the<CODE> low_level_convert()</CODE> static member function
|
||||
exposed by the converter.</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD> <A HREF="converter_policies.html#rc"><CODE>UserRangeChecker</CODE></A> </TD>
|
||||
<TD><i>Special and Optional</i> <b>Stateless Policy</b> which can be used to override
|
||||
the internal range checking logic.<br>
|
||||
If given, supplies alternative code for the out_of_range() and validate_range()
|
||||
static member functions exposed by the converter.</TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
<br>
|
||||
<hr>
|
||||
<h2>Member functions:</h2>
|
||||
<P><CODE>static result_type converter<>::convert ( argument_type s ) ; //
|
||||
throw</CODE></P>
|
||||
<BLOCKQUOTE>
|
||||
<P>This static member function converts an rvalue of type source_type to an rvalue
|
||||
of type target_type.<BR>
|
||||
If the conversion requires it, it performs a range checking before the conversion
|
||||
and passes the result of the check to the overflow handler policy (the default
|
||||
policy throws an exception if out-of-range is detected)<BR>
|
||||
The implementation of this function is actually built from the policies and
|
||||
is basically as follows:</P>
|
||||
<PRE> result_type converter<>::convert ( argument_type s )
|
||||
{
|
||||
validate_range(s); // Implemented by the internal range checking logic
|
||||
// (which also calls the OverflowHandler policy)
|
||||
// or externally supplied by the UserRangeChecker policy.
|
||||
|
||||
s = nearbyint(s); // Externally supplied by the Float2IntRounder policy.
|
||||
// NOTE: This is actually called only for float to int conversions.
|
||||
|
||||
return low_level_convert(s); // Externally supplied by the RawConverter policy.
|
||||
}
|
||||
</PRE>
|
||||
|
||||
<P>"converter<>::operator() const" just calls <CODE>convert()</CODE></P>
|
||||
</BLOCKQUOTE>
|
||||
<P><CODE>static range_check_result numeric_converter<>::out_of_range (
|
||||
argument_type s ) ;</CODE></P>
|
||||
<BLOCKQUOTE>
|
||||
<P>This <A HREF="#int">internal</A> static member function determines if the
|
||||
value 's' can be represented by the target type without overflow. <BR>
|
||||
It does not determine if the conversion is <EM>exact</EM>; that is, it does
|
||||
not detect <i>inexact</i> conversions, only <i>out-of-range</i> conversions
|
||||
(see the <a href="definitions.html#roundoff">Definitions</a> for further details).<BR>
|
||||
The return value is of enum type
|
||||
<A HREF="converter_policies.html#rcr"><CODE>boost::numeric::range_check_result</CODE></A><BR>
|
||||
The actual code for the range checking logic is optimized for the combined
|
||||
properties of the source and target types. For example, a non-subranged conversion
|
||||
(i.e: int->float), requires no range checking, so out_of_range() returns
|
||||
cInRange directly. See the following <A HREF="#rchklogic">table</A> for more
|
||||
details.<br>
|
||||
If the user supplied a <a href="converter_policies.html#rc">UserRangeChecker</a>
|
||||
policy, is this policy which implements this function, so the implementation
|
||||
is user defined, although it is expected to perform the same conceptual check
|
||||
and return the appropriate result.</P>
|
||||
</BLOCKQUOTE>
|
||||
<P><CODE>static void numeric_converter<>::validate_range ( argument_type
|
||||
s ) ; // no throw</CODE></P>
|
||||
<BLOCKQUOTE>
|
||||
<P>This <A HREF="#int">internal</A> static member function calls <CODE>out_of_range(s)</CODE>,
|
||||
and passes the result to the <A
|
||||
HREF="converter_policies.html#oh"><CODE>OverflowHandler</CODE></A> policy class
|
||||
<BR>
|
||||
For those Target/Source combinations which don't require range checking, this
|
||||
is an <U>empty inline function</U>.<br>
|
||||
If the user supplied a <a href="converter_policies.html#rc">UserRangeChecker</a>
|
||||
policy, is this policy which implements this function, so the implementation
|
||||
is user defined, although it is expected to perform the same action as the
|
||||
default. In particular, it is expected to pass the result of the check to
|
||||
the overflow handler.</P>
|
||||
</BLOCKQUOTE>
|
||||
<P><CODE>static result_type numeric_converter<>::low_level_convert (
|
||||
argument_type s ) ;</CODE></P>
|
||||
<BLOCKQUOTE>
|
||||
<P>This <A HREF="#int">internal</A> static member function performs the actual
|
||||
conversion.<BR>
|
||||
This function is externally supplied by the <A
|
||||
HREF="converter_policies.html#rawc"><CODE>RawConverter</CODE></A> policy class.</P>
|
||||
</BLOCKQUOTE>
|
||||
<P><CODE>static source_type converter<>::nearbyint (
|
||||
argument_type s ) ;</CODE></P>
|
||||
<BLOCKQUOTE>
|
||||
<P>This <A HREF="#int">internal</A> static member function, which is <U>only
|
||||
used</U> for float to int conversions, returns an <I>integer value of <U>floating-point
|
||||
type</U></I> according to some rounding direction. <BR>
|
||||
This function is externally supplied by the <A
|
||||
HREF="converter_policies.html#f2i"><CODE>Float2IntRounder</CODE></A> policy class
|
||||
which encapsulates the specific rounding mode.</P>
|
||||
</BLOCKQUOTE>
|
||||
<hr>
|
||||
<P><A NAME="int"><B>Internal Member Functions</B>:</A> These static member functions
|
||||
build the actual conversion code used by <CODE>convert()</CODE>. The user does
|
||||
not have to call these if calling convert(), since convert() calls them infernally,
|
||||
but they can be called separately for specific needs.</P>
|
||||
<hr>
|
||||
<H2><A NAME="rchklogic">Range Checking Logic</A></H2>
|
||||
<P>The Following table summarizes the internal range checking logic performed
|
||||
for each combination of the properties of Source and Target.<br>
|
||||
LowestT/HighestT denotes the highest and lowest values of the Target type, respectively.<br>
|
||||
S(n) is short for "static_cast<S>(n)" (S denotes the Source
|
||||
type).<br>
|
||||
"NONE" indicates that for this case there is no range checking.</P>
|
||||
<Pre> int_to_int |--> sig_to_sig |--> subranged |--> ( s >= S(LowestT) ) && ( s <= S(HighestT) )
|
||||
| |--> not subranged |--> NONE
|
||||
|
|
||||
|--> unsig_to_unsig |--> subranged |--> ( s >= S(LowestT) ) && ( s <= S(HighestT) )
|
||||
| |--> not subranged |--> NONE
|
||||
|
|
||||
|--> sig_to_unsig |--> pos subranged |--> ( s >= S(0) ) && ( s <= S(HighestT) )
|
||||
| |--> not pos subranged |--> ( s >= S(0) )
|
||||
|
|
||||
|--> unsig_to_sig |--> subranged |--> ( s <= S(HighestT) )
|
||||
| |--> not subranged |--> NONE
|
||||
|
||||
int_to_float |--> NONE
|
||||
|
||||
float_to_int |--> round_to_zero |--> ( s > S(LowestT)-S(1) ) && ( s < S(HighestT)+S(1) )
|
||||
|--> round_to_even_nearest |--> ( s >= S(LowestT)-S(0.5) ) && ( s < S(HighestT)+S(0.5) )
|
||||
|--> round_to_infinity |--> ( s > S(LowestT)-S(1) ) && ( s <= S(HighestT) )
|
||||
|--> round_to_neg_infinity |--> ( s >= S(LowestT) ) && ( s < S(HighestT)+S(1) )
|
||||
|
||||
float_to_float |--> subranged |--> ( s >= S(LowestT) ) && ( s <= S(HighestT) )
|
||||
|--> not subranged |--> NONE
|
||||
|
||||
</Pre>
|
||||
<HR>
|
||||
<H2><A NAME="examples">Examples</A></H2>
|
||||
<BLOCKQUOTE>
|
||||
<PRE> #include <cassert>
|
||||
#include <boost/numeric/conversion/converter.hpp>
|
||||
|
||||
int main() {
|
||||
|
||||
typedef boost::numeric::converter<int,double> Double2Int ;
|
||||
|
||||
int x = Double2Int::convert(2.0);
|
||||
assert ( x == 2 );
|
||||
|
||||
int y = Double2Int()(3.14); // As a function object.
|
||||
assert ( y == 3 ) ; // The default rounding is trunc.
|
||||
|
||||
try
|
||||
{
|
||||
double m = boost::numeric::bounds<double>::highest();
|
||||
int z = Double2Int::convert(m); // By default throws positive_overflow()
|
||||
}
|
||||
catch ( boost::numeric::positive_overflow const& )
|
||||
{
|
||||
}
|
||||
|
||||
return 0;
|
||||
}</PRE>
|
||||
</BLOCKQUOTE>
|
||||
<HR>
|
||||
<P>Back to <A HREF="index.html">Numeric Conversion library index</A></P>
|
||||
<HR>
|
||||
<P>Revised 16 May 2005</P>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</BODY>
|
||||
</HTML>
|
||||
@@ -1,466 +0,0 @@
|
||||
<HTML>
|
||||
|
||||
<HEAD>
|
||||
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
|
||||
<LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css">
|
||||
<TITLE>Boost Numeric Conversion Library - Converter Policies</TITLE>
|
||||
</HEAD>
|
||||
|
||||
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000ff" VLINK="#800080">
|
||||
<TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%"
|
||||
SUMMARY="header">
|
||||
<TR>
|
||||
<TD VALIGN="top" WIDTH="300"> <H3><A HREF="http://www.boost.org"><IMG
|
||||
HEIGHT="86" WIDTH="277" ALT="C++ Boost" SRC="../../../../boost.png"
|
||||
BORDER="0"></A> </H3>
|
||||
</TD>
|
||||
<TD VALIGN="top"> <H1 ALIGN="center">Boost Numeric Conversion Library</H1>
|
||||
<H1><A HREF="http://www.boost.org">Header </A><A
|
||||
HREF="../../../../boost/numeric/conversion/converter_policies.hpp">boost/numeric/conversion/converter_policies.hpp</A></H1>
|
||||
</TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
<HR>
|
||||
<H2>Contents</H2>
|
||||
<ol>
|
||||
<LI><A HREF="#rcr"><CODE>enumeration range_check_result</CODE></A> </LI>
|
||||
<LI><A HREF="#oh"><CODE>Policy OverflowHandler</CODE></A>
|
||||
<UL>
|
||||
<LI>class <A HREF="#oh_silent"><CODE>silent_overflow_handler</CODE></A></LI>
|
||||
<LI>class <A HREF="#oh_def"><CODE>def_overflow_handler</CODE></A> (Default Policy)</LI>
|
||||
<ul>
|
||||
<LI>class <CODE> <A HREF="#bad_numc">bad_numeric_cast</A></CODE> <a href="#x-note">(see IMPORTANT note)</a></LI>
|
||||
<LI>class <A HREF="#negovr"><CODE>negative_overflow</CODE></A></LI>
|
||||
<LI>class <A HREF="#posovr"><CODE>positive_overflow</CODE></A></LI>
|
||||
</ul>
|
||||
</UL>
|
||||
</LI>
|
||||
<LI><A HREF="#f2i"><CODE>Policy FloatToIntRounder</CODE></A> <UL>
|
||||
<LI>class <A HREF="#trunc"><CODE>Trunc<T></CODE></A> (Default Policy)</LI>
|
||||
<LI>class <A HREF="#round"><CODE>RoundEven<T></CODE></A></LI>
|
||||
<LI>class <A HREF="#ceil"><CODE>Ceil<T></CODE></A></LI>
|
||||
<LI>class <A HREF="#floor"><CODE>Floor<T></CODE></A></LI>
|
||||
</UL>
|
||||
</LI>
|
||||
<LI><A HREF="#rawc"><CODE>Policy RawConverter</CODE></A><UL>
|
||||
<LI>class <A HREF="#rawnumc"><CODE>raw_converter class</CODE></A> (Default)</LI>
|
||||
</UL>
|
||||
</LI>
|
||||
<LI><A HREF="#rc"><CODE>Policy UserRangeChecker</CODE></A><UL>
|
||||
<LI>class <A HREF="#int_rc"><CODE>UseInternalRangeChecker class</CODE></A> (Default)</LI>
|
||||
</UL>
|
||||
</LI>
|
||||
</ol>
|
||||
|
||||
<HR>
|
||||
<H2><A NAME="types">Types</A></H2>
|
||||
<H2><A NAME="rcr"><CODE>enum range_check_result</CODE></A></H2>
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
enum range_check_result
|
||||
|
||||
{
|
||||
|
||||
cInRange ,
|
||||
|
||||
cNegOverflow ,
|
||||
|
||||
cPosOverflow
|
||||
|
||||
} ;
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
} }</PRE>
|
||||
|
||||
<P>Defines the values returned by <CODE>boost::numeric::converter<>::out_of_range()</CODE>
|
||||
</P>
|
||||
<HR>
|
||||
<H2><A NAME="oh">Policy <CODE>OverflowHandler</CODE></A></H2>
|
||||
<P>This <EM>stateless</EM> non-template policy class must be a <I>function object</I>
|
||||
and is called to administrate the result of the range checking. It can throw
|
||||
an exception if overflow has been detected by the range checking as indicated
|
||||
by its argument. If it throws, is is recommended that it be <CODE>std::bad_cast</CODE>
|
||||
or derived.</P>
|
||||
<P>It must have the following interface (it does not has to be a template class):</P>
|
||||
<PRE> struct YourOverflowHandlerPolicy
|
||||
|
||||
{
|
||||
|
||||
void operator() ( boost::range_check_result ) ; // throw bad_cast or derived
|
||||
|
||||
} ;
|
||||
|
||||
</PRE>
|
||||
<P>It is called with the result of the converter's <CODE>out_of_range()</CODE>
|
||||
inside <CODE>validate_range()</CODE>.</P>
|
||||
<P>These are the two overflow handler classes provided by the
|
||||
library:</P>
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
struct <A NAME="oh_def">def_overflow_handler</a>
|
||||
|
||||
{
|
||||
|
||||
void operator() ( range_check_result r ) // throw bad_numeric_conversion derived
|
||||
|
||||
{
|
||||
|
||||
if ( r == cNegOverflow )
|
||||
|
||||
throw negative_overflow() ;
|
||||
|
||||
else if ( r == cPosOverflow )
|
||||
|
||||
throw positive_overflow() ;
|
||||
|
||||
}
|
||||
|
||||
} ;
|
||||
|
||||
|
||||
|
||||
struct <A NAME="oh_silent">silent_overflow_handler</a>
|
||||
|
||||
{
|
||||
|
||||
void operator() ( range_check_result ) // no-throw
|
||||
|
||||
{}
|
||||
|
||||
} ;
|
||||
|
||||
|
||||
|
||||
} }
|
||||
|
||||
</PRE>
|
||||
|
||||
<P>And these are the Exception Classes thrown by the default
|
||||
overflow handler <a href="#x-note">(see IMPORTANT note)</a></P>
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
class <a name="bad_numc">bad_numeric_cast</a> : public std::bad_cast
|
||||
|
||||
{
|
||||
|
||||
public:
|
||||
|
||||
|
||||
|
||||
virtual const char *what() const // throw()
|
||||
|
||||
{ return "bad numeric conversion: overflow"; }
|
||||
|
||||
};
|
||||
|
||||
|
||||
|
||||
class <a name="negovr">negative_overflow</a> : public bad_numeric_cast
|
||||
{
|
||||
|
||||
public:
|
||||
|
||||
|
||||
|
||||
virtual const char *what() const // throw()
|
||||
|
||||
{ return "bad numeric conversion: negative overflow"; }
|
||||
|
||||
};
|
||||
|
||||
class <a name="posovr">positive_overflow</a> : public bad_numeric_cast
|
||||
{
|
||||
|
||||
public:
|
||||
|
||||
|
||||
|
||||
virtual const char *what() const // throw()
|
||||
|
||||
{ return "bad numeric conversion: positive overflow"; }
|
||||
|
||||
};
|
||||
|
||||
} }
|
||||
|
||||
</PRE>
|
||||
|
||||
<a name="x-note"><p><b>IMPORTANT RELEASE NOTE for 1.33</b></p></a>
|
||||
<blockquote>
|
||||
<p>Previous to boost version 1.33, the exception class <code>bad_numeric_cast</code> was
|
||||
named <code>bad_numeric_conversion</code>. However, in 1.33, the old function
|
||||
<code>numeric_cast<></code> from <code>boost/cast.hpp</code> was completly replaced by the new
|
||||
<code>numeric_cast<></code> in <code>boost/numeric/conversion/cast.hpp</code>
|
||||
(and <code>boost/cast.hpp</code> is including <code>boost/numeric/conversion/cast.hpp</code> now). That old function which
|
||||
existed in boost for quite some time used the <code>bad_numeric_cast</code> as its
|
||||
exception type so I decided to avoid backward compatibility problems by adopting it (guessing
|
||||
that the user base for the old code is wider than for the new code).</p>
|
||||
</blockquote>
|
||||
|
||||
<HR>
|
||||
<H2><A NAME="f2i">Policy <CODE>FloatToIntRounder</CODE></A></H2>
|
||||
<P>This <EM>stateless</EM> template policy class specifies the rounding mode used
|
||||
for<U> float to integral</U> conversions. It supplies the <CODE>"nearbyint()"</CODE>
|
||||
static member function exposed by the converter, which means that it <U>publicly
|
||||
inherits from this policy.</U></P>
|
||||
<P>The policy must have the following interface:</P>
|
||||
<PRE> template<class S>
|
||||
|
||||
struct YourFloat2IntRounderPolicy
|
||||
|
||||
{
|
||||
|
||||
typedef S source_type ;
|
||||
|
||||
typedef <I>{S or S const&}</I> argument_type ;
|
||||
|
||||
|
||||
|
||||
static source_type nearbyint ( argument_type s ) { ... }
|
||||
|
||||
|
||||
|
||||
typedef mpl::integral_c<std::float_round_style,std::<i>round_...</i>> round_style ;
|
||||
|
||||
} ;
|
||||
|
||||
</PRE>
|
||||
|
||||
<P>These are the rounder classes provided by the library:</P>
|
||||
|
||||
<BLOCKQUOTE>
|
||||
<P><EM>NOTE: These classes are not intended to be general purpose rounding functions
|
||||
but specific policies for converter<>. This is why <U>they are not function
|
||||
objects</U>.</EM></P>
|
||||
<P>(only the specific parts are shown, see the general policy form above)</P>
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
|
||||
|
||||
<A NAME="trunc"></A>template<class S>
|
||||
|
||||
struct Trunc
|
||||
|
||||
{
|
||||
|
||||
static source_type nearbyint ( argument_type s )
|
||||
|
||||
{
|
||||
|
||||
using std::floor ;
|
||||
|
||||
using std::ceil ;
|
||||
|
||||
return s >= static_cast<S>(0) ? floor(s) : ceil(s) ;
|
||||
|
||||
}
|
||||
|
||||
|
||||
|
||||
typedef mpl::integral_c<std::float_round_style,std::round_toward_zero> round_style ;
|
||||
|
||||
} ;
|
||||
|
||||
</PRE>
|
||||
<PRE> <A NAME="round"></A>template<class S>
|
||||
|
||||
struct RoundEven
|
||||
|
||||
{
|
||||
|
||||
static source_type nearbyint ( argument_type s )
|
||||
|
||||
{
|
||||
|
||||
return <i>impl-defined-value</i> ;
|
||||
|
||||
}
|
||||
|
||||
|
||||
|
||||
typedef mpl::integral_c<std::float_round_style,std::round_to_nearest> round_style ;
|
||||
|
||||
} ;
|
||||
|
||||
</PRE>
|
||||
<PRE> <A NAME="ceil"></A>template<class S>
|
||||
|
||||
struct Ceil
|
||||
|
||||
{
|
||||
|
||||
static source_type nearbyint ( argument_type s )
|
||||
|
||||
{<br> using std::ceil ;<br> return ceil(s) ;<br> }
|
||||
|
||||
|
||||
|
||||
typedef mpl::integral_c<std::float_round_style,std::round_toward_infinity> round_style ;
|
||||
|
||||
} ;
|
||||
|
||||
</PRE>
|
||||
<PRE> <A NAME="floor"></A>template<class S>
|
||||
|
||||
struct Floor
|
||||
|
||||
{
|
||||
|
||||
static source_type nearbyint ( argument_type s )
|
||||
|
||||
{<br> using std::floor ;<br> return floor(s) ;<br> }
|
||||
|
||||
|
||||
|
||||
typedef mpl::integral_c<std::float_round_style,std::round_toward_neg_infinity> round_style ;
|
||||
|
||||
} ;
|
||||
|
||||
|
||||
|
||||
} } // namespace numeric, namespace boost</PRE>
|
||||
|
||||
</BLOCKQUOTE>
|
||||
<H3>Math Functions used by the rounder policies</H3>
|
||||
<P>The rounder policies supplied by this header use math functions floor() and
|
||||
ceil(). The standard versions of these functions are introduced in context by
|
||||
a using directive, so in normal conditions, the standard functions will be used.
|
||||
<br>
|
||||
However, if there are other visible corresponding overloads an ambiguity could
|
||||
arise. In this case, the user can supply her own rounder policy which could,
|
||||
for instance, use a fully qualified call.<br>
|
||||
This technique allows the default rounder policies to be used directly with
|
||||
user defined types. The user only requires that suitable overloads of floor()
|
||||
and ceil() be visible. See also <a HREF="requirements.html">User Defined Numeric Types support</a><br>
|
||||
</P>
|
||||
<HR>
|
||||
<H2><A NAME="rawc">Policy <CODE>RawConverter</CODE></A></H2>
|
||||
<P>This <EM>stateless</EM> template policy class is used to perform the actual
|
||||
conversion from Source to Target. It supplies the <CODE>"low_level_convert()"</CODE>
|
||||
static member function exposed by the converter, which means that it <U>publicly
|
||||
inherits from this policy.</U></P>
|
||||
<P>The policy must have the following interface:</P>
|
||||
<PRE> template<class Traits>
|
||||
|
||||
struct YourRawConverterPolicy
|
||||
|
||||
{
|
||||
|
||||
typedef typename Traits::result_type result_type ;
|
||||
|
||||
typedef typename Traits::argument_type argument_type ;
|
||||
|
||||
|
||||
|
||||
static result_type low_level_convert ( argument_type s ) { return <I><impl defined></I> ; }
|
||||
|
||||
} ;
|
||||
|
||||
</PRE>
|
||||
|
||||
<P>This policy is mostly provided as a hook for user defined types which don't
|
||||
support <CODE>static_cast<></CODE> conversions to some types</P>
|
||||
|
||||
<P>This is the only raw converter policy class provided
|
||||
by the library:</P>
|
||||
<PRE>namespace boost { namespace numeric {
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
template<class Traits>
|
||||
|
||||
struct <A NAME="rawnumc">raw_numeric_converter</A>
|
||||
|
||||
{
|
||||
|
||||
typedef typename Traits::result_type result_type ;
|
||||
|
||||
typedef typename Traits::argument_type argument_type ;
|
||||
|
||||
|
||||
|
||||
static result_type low_level_convert ( argument_type s )
|
||||
|
||||
{ return static_cast<result_type>(s) ; }
|
||||
|
||||
} ;
|
||||
|
||||
|
||||
|
||||
}
|
||||
|
||||
</PRE>
|
||||
|
||||
<HR>
|
||||
<H2><A NAME="rc">Policy <CODE>UserRangeChecker</CODE></A></H2>
|
||||
<P>This <EM>stateless</EM> template policy class is used -<u>only if supplied</u>-
|
||||
to <b>override</b> the internal range checking logic.<br>
|
||||
It supplies the <CODE>"validate_range()"</CODE> static member function
|
||||
exposed by the converter, which means that it <U>publicly inherits from this
|
||||
policy.</U></P>
|
||||
<P>The policy must have the following interface:</P>
|
||||
<PRE> template<class Traits>
|
||||
|
||||
struct YourRangeCheckerPolicy
|
||||
|
||||
{
|
||||
|
||||
typedef typename Traits::argument_type argument_type ;
|
||||
|
||||
|
||||
|
||||
// Determines if the value 's' fits in the range of the Target type.
|
||||
|
||||
static range_check_result out_of_range ( argument_type s ) ;
|
||||
|
||||
|
||||
|
||||
// Checks whether the value 's' is out_of_range()
|
||||
|
||||
// and passes the result of the check to the OverflowHandler policy.
|
||||
|
||||
static void validate_range ( argument_type s )
|
||||
|
||||
{
|
||||
|
||||
OverflowHandler()( out_of_range(s) ) ;
|
||||
|
||||
}
|
||||
|
||||
} ;
|
||||
|
||||
</PRE>
|
||||
<P>This policy is <b>only</b> provided as a hook for user defined types which
|
||||
require range checking (which is disabled by default when a UDT is involved).<br>
|
||||
The library provides a class: <A NAME="int_rc"><code>UseInternalRangeChecker{};</code></a> which
|
||||
is a <i>fake</i> RangeChecker policy used to signal the converter to use its
|
||||
internal range checking implementation.
|
||||
</P>
|
||||
<HR>
|
||||
<P>Back to <A HREF="index.html">Numeric Conversion library index</A></P>
|
||||
<HR>
|
||||
<P>Revised 23 June 2004</P>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</BODY>
|
||||
</HTML>
|
||||
@@ -1,471 +0,0 @@
|
||||
<HTML>
|
||||
<HEAD>
|
||||
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
|
||||
<LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css">
|
||||
<TITLE>Boost Numeric Conversion Library - Definitions</TITLE>
|
||||
</HEAD>
|
||||
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000ff" VLINK="#800080">
|
||||
<TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%"
|
||||
SUMMARY="header">
|
||||
<TR>
|
||||
<TH VALIGN="top" WIDTH="300">
|
||||
<H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277"
|
||||
ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH>
|
||||
<TH VALIGN="top">
|
||||
<H1 ALIGN="center">Boost Numeric Conversion Library</H1>
|
||||
<H1 ALIGN="center">Definitions</H1>
|
||||
</TH>
|
||||
</TR>
|
||||
</TABLE>
|
||||
<HR>
|
||||
<H2>Contents</H2>
|
||||
<DL CLASS="page-index">
|
||||
<dt><A HREF="#intro">Introduction</A></dt>
|
||||
<dt><A HREF="#typeval">Types and Values</A></dt>
|
||||
<dt><A HREF="#stdtypes">C++ Arithmetic Types</A></dt>
|
||||
<dt><A HREF="#numtypes">Numeric Types</A></dt>
|
||||
<dt><A HREF="#range">Range and Precision</A></dt>
|
||||
<dt><A HREF="#roundoff">Exact, Correctly Rounded and Out-Of-Range Representations</A></dt>
|
||||
<dt><A HREF="#stdconv">Standard (numeric) Conversions</A></dt>
|
||||
<dt><A HREF="#subranged">Subranged Conversion Direction, Subtype and Supertype</A></dt>
|
||||
</DL>
|
||||
|
||||
|
||||
|
||||
<h2><A NAME="intro">Introduction</A></h2>
|
||||
<P>This section provides definitions of terms used in the Numeric Conversion library.</p>
|
||||
<p><b>Notation:</b>
|
||||
<li><u>underlined text</u> denotes terms defined in the C++ standard.</li>
|
||||
<li><b>bold face</b> denotes terms defined here but not in the standard.</li>
|
||||
<p></p>
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<h2><A NAME="typeval">Types and Values</A></h2>
|
||||
<p>As defined by the <u>C++ Object Model</u> (§1.7) the <u>storage</u> or
|
||||
memory on which a C++ program runs is a contiguous sequence of <u>bytes</u>
|
||||
where each byte is a contiguous sequence of <u>bits</u>.<br>
|
||||
An <u>object</u> is a region of storage (§1.8) and has a type (§3.9).<br>
|
||||
A <u>type</u> is a discrete set of values. <br>
|
||||
An object of type T has an <u>object representation</u> which is the sequence
|
||||
of bytes stored in the object (§3.9/4)<br>
|
||||
An object of type T has a <u>value representation</u> which is the set of bits
|
||||
that determine the <i>value</i> of an object of that type (§3.9/4). For
|
||||
<u>POD</u> types (§3.9/10), this bitset is given by the object representation,
|
||||
but not all the bits in the storage need to participate in the value representation
|
||||
(except for character types): for example, some bits might be used for padding
|
||||
or there may be trap-bits.</p>
|
||||
<p>The <b>typed value</b> that is held by an object is
|
||||
the value which is determined by its value representation.<br>
|
||||
An <b>abstract value</b> (untyped) is
|
||||
the conceptual information that is represented in a type
|
||||
(i.e. the number π).<br>
|
||||
The <b>intrinsic value</b> of an object is
|
||||
the binary value of the sequence of unsigned characters which form its object representation.</p>
|
||||
<p><i>Abstract values</i> can be <b>represented</b> in a given type.<br>
|
||||
To <b>represent</b> an abstract value 'V' in a type 'T'
|
||||
is to obtain a typed value 'v' which <i>corresponds</i> to the abstract value 'V'.<br>
|
||||
The operation is denoted using the 'rep()' operator, as in: <code>v=rep(V)</code>.<br>
|
||||
'v' is the <b>representation</b> of 'V' in the type 'T'.<br>
|
||||
For example, the abstract value π can be represented in the type <code>'double'</code> as the
|
||||
'double value M_PI' and in the type <code>'int'</code> as the 'int value 3'</p>
|
||||
<p>Conversely, <i>typed values</i> can be <b>abstracted</b>.<br>
|
||||
To <b>abstract</b> a typed value 'v' of type 'T' is to obtain the
|
||||
abstract value 'V' whose representation in 'T' is 'v'.<br>
|
||||
The operation is denoted using the 'abt()' operator, as in: <code>V=abt(v)</code>.<br>
|
||||
'V' is the <b>abstraction</b> of 'v' of type 'T'.<br>
|
||||
Abstraction is just an abstract operation (you can't do it); but it is defined nevertheless
|
||||
because it will be used to give the definitions in the rest of this document.</p>
|
||||
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<h2><A NAME="stdtypes">C++ Arithmetic Types</A></h2>
|
||||
<P>The C++ language defines <u>fundamental types</u> (§3.9.1). The following
|
||||
subsets of the fundamental types are intended to represent <i>numbers</i>:</p>
|
||||
<li><u>signed integer types</u> (§3.9.1/2):<br>
|
||||
<blockquote>
|
||||
<code>{signed char, signed short int, signed int, signed long int}</code><br>
|
||||
Can be used to represent general integer numbers (both negative and positive).
|
||||
</blockquote>
|
||||
</li>
|
||||
<li><u>unsigned integer types</u> (§3.9.1/3):<br>
|
||||
<blockquote>
|
||||
<code>{unsigned char, unsigned short int, unsigned int, unsigned long int}</code><br>
|
||||
Can be used to represent positive integer numbers <u>with modulo-arithmetic</u>.<br>
|
||||
</blockquote>
|
||||
<li><u>floating-point types</u> (§3.9.1/8):<br>
|
||||
<blockquote>
|
||||
<code>{float,double,long double}</code><br>
|
||||
Can be used to represent real numbers.
|
||||
</blockquote>
|
||||
</li>
|
||||
<li><u>integral or integer types</u> (§3.9.1/7):<br>
|
||||
<blockquote>
|
||||
<code>{{signed integers},{unsigned integers}, bool, char and wchar_t}</code>
|
||||
</blockquote>
|
||||
</li>
|
||||
<li><u>arithmetic types</u> (§3.9.1/8):<br>
|
||||
<blockquote>
|
||||
<code>{{integer types},{floating types}}</code>
|
||||
</blockquote>
|
||||
</li>
|
||||
<P>The integer types are required to have a <i>binary</i> value representation.<br>
|
||||
Additionally, the signed/unsigned integer types of the same base type (short, int or long)
|
||||
are required to have the same value representation, that is:</P>
|
||||
<pre> int i = -3 ; // suppose value representation is: 10011 (sign bit + 4 magnitude bits)
|
||||
unsigned int u = i ; // u is required to have the same 10011 as its value representation.
|
||||
</pre>
|
||||
<P>In other words, the integer types signed/unsigned X use the same value representation
|
||||
but a different <i>interpretation</i> of it; that is, their <i>typed values</i>
|
||||
might differ.<br>
|
||||
Another consequence of this is that the range for signed X is always a smaller subset
|
||||
of the range of unsigned X, as required by §3.9.1/3.</P>
|
||||
<P>Note: always remember that unsigned types, unlike signed types, have modulo-arithmetic;
|
||||
that is, they do not overflow.<br>
|
||||
This means that:
|
||||
<li> Always be extra careful when mixing signed/unsigned types</li>
|
||||
<li> Use unsigned types only when you need modulo arithmetic or very very large numbers.
|
||||
Don't use unsigned types just because you intend to deal with positive values only
|
||||
(you can do this with signed types as well).</li>.
|
||||
<p></P>
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<h2><A NAME="numtypes">Numeric Types</A></h2>
|
||||
<p>This section introduces the following definitions intended to integrate arithmetic
|
||||
types with user-defined types which behave like numbers. Some definitions are
|
||||
purposely broad in order to include a vast variety of user-defined number
|
||||
types.</p>
|
||||
<p>Within this library, the term <i>number</i> refers to an abstract numeric value.</p>
|
||||
<p>A type is <b>numeric</b> if:</p>
|
||||
<li>It is an arithmetic type, or,</li>
|
||||
<li>It is a user-defined type which</li>
|
||||
<blockquote>
|
||||
<li>Represents numeric abstract values (i.e. numbers).</li>
|
||||
|
||||
<li>Can be converted (either implicitly or explicitly) to/from at least one
|
||||
arithmetic type.</li>
|
||||
<li>Has <a href="#range">range</a> (possibly unbounded) and <a href="#range">precision</a>
|
||||
(possibly dynamic or unlimited).</li>
|
||||
<li>Provides an specialization of <code>std::numeric_limits</code>.</li>
|
||||
</blockquote>
|
||||
<p></p>
|
||||
<p>A numeric type is <b>signed</b> if the abstract values it represent include negative numbers.<br>
|
||||
A numeric type is <b>unsigned</b> if the abstract values it represent exclude negative numbers.<br>
|
||||
A numeric type is <b>modulo</b> if it has modulo-arithmetic (does not overflow).<br>
|
||||
A numeric type is <b>integer</b> if the abstract values it represent are whole numbers.<br>
|
||||
A numeric type is <b>floating</b> if the abstract values it represent are real numbers.<br>
|
||||
An <b>arithmetic value</b> is the typed value of an arithmetic type<br>
|
||||
A <b>numeric value</b> is the typed value of a numeric type</p>
|
||||
<p></p>
|
||||
<p>These definitions simply generalize the standard notions of arithmetic types
|
||||
and values by introducing a superset called <u>numeric</u>. All arithmetic types
|
||||
and values are numeric types and values, but not vice versa, since user-defined
|
||||
numeric types are not arithmetic types.</p>
|
||||
<p>The following examples clarify the differences between arithmetic and numeric types (and values):</p>
|
||||
<pre>// A numeric type which is not an arithmetic type (is user-defined)
|
||||
// and which is intended to represent integer numbers (i.e., an 'integer' numeric type)
|
||||
class MyInt
|
||||
{
|
||||
MyInt ( long long v ) ;
|
||||
long long to_builtin();
|
||||
} ;
|
||||
namespace std {
|
||||
template<> numeric_limits<MyInt> { ... } ;
|
||||
}
|
||||
|
||||
// A 'floating' numeric type (double) which is also an arithmetic type (built-in),
|
||||
// with a float numeric value.
|
||||
double pi = M_PI ;
|
||||
|
||||
// A 'floating' numeric type with a whole numeric value.
|
||||
// NOTE: numeric values are typed valued, hence, they are, for instance,
|
||||
// integer or floating, despite the value itself being whole or including
|
||||
// a fractional part.
|
||||
double two = 2.0 ;
|
||||
|
||||
// An integer numeric type with an integer numeric value.
|
||||
MyInt i(1234);
|
||||
</pre>
|
||||
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<h2><A NAME="range">Range and Precision</A></h2>
|
||||
<p>Given a number set 'N', some of its elements are representable in a numeric type 'T'.<br>
|
||||
The set of representable values of type 'T', or numeric set of 'T', is a set of numeric values
|
||||
whose elements are the representation of some <i>subset</i> of 'N'.<br>
|
||||
For example, the interval of 'int' values [INT_MIN,INT_MAX] is the set of representable values
|
||||
of type 'int', i.e. the 'int' numeric set, and corresponds to the representation of the elements
|
||||
of the interval of abstract values [abt(INT_MIN),abt(INT_MAX)] from the integer numbers.<br>
|
||||
Similarly, the interval of 'double' values [-DBL_MAX,DBL_MAX] is the 'double' numeric set,
|
||||
which corresponds to the subset of the real numbers from abt(-DBL_MAX) to abt(DBL_MAX).
|
||||
</p>
|
||||
<p>Let <b>next(x)</b> denote the lowest numeric value greater than x.<br>
|
||||
Let <b>prev(x)</b> denote the highest numeric value lower then x.</p>
|
||||
<p>Let <code><b>v=prev(next(V))</b></code> and <code><b>v=next(prev(V))</b></code> be identities that relate a numeric
|
||||
typed value 'v' with a number 'V'.</p>
|
||||
<p>An ordered pair of numeric values <i>x,y</i> s.t. <i>x<y</i> are <b>consecutive</b> iff
|
||||
<code>next(x)==y</code>.</p>
|
||||
<p>The abstract distance between consecutive numeric values is usually referred
|
||||
to as a <u>Unit in the Last Place</u>, or <b>ulp</b> for short. A ulp is a quantity whose abstract
|
||||
magnitude is <i>relative</i> to the numeric values it corresponds to: If the numeric set is not evenly
|
||||
distributed, that is, if the abstract distance between consecutive numeric values varies along the set
|
||||
-as is the case with the floating-point types-, the magnitude of 1ulp after the numeric value x
|
||||
might be (usually is) different from the magnitude of a 1ulp after the numeric value y for x!=y.</p>
|
||||
<p>Since numbers are inherently ordered, a <b>numeric set</b> of type 'T'
|
||||
is an ordered sequence of numeric values (of type 'T') of the form:
|
||||
</p>
|
||||
<p><code>REP(T)={l,next(l),next(next(l)),...,prev(prev(h)),prev(h),h}</code>
|
||||
</p>
|
||||
<p>where 'l' and 'h' are respectively the lowest and highest values of type 'T', called the
|
||||
<b>boundary values</b> of type T.</p>
|
||||
<p>A numeric set is discrete. It has a <b>size</b> which is the number
|
||||
of numeric values in the set, a <b>width</b> which is the abstract difference between
|
||||
the highest and lowest boundary values: [abt(h)-abt(l)], and a <b>density</b>
|
||||
which is the relation between its size and width: 'density=size/width'.<br>
|
||||
The integer types have density 1, which means that there are no unrepresentable integer numbers
|
||||
between abt(l) and abt(h) (i.e. there are no gaps). On the other hand,
|
||||
floating types have density much smaller than 1, which means that there are
|
||||
real numbers unrepresented between consecutive floating values (i.e. there are gaps).
|
||||
</p>
|
||||
<p>The interval of <u>abstract values</u> [abt(l),abt(h)] is the <b>range</b> of the type 'T',
|
||||
denoted 'R(T)'.<br>
|
||||
A range is a set of abstract values and not a set of numeric values. In other
|
||||
documents, such as the C++ standard, the word 'range' is <i>sometimes</i> used
|
||||
as synonym for 'numeric set', that is, as the ordered sequence of numeric values
|
||||
from 'l' to 'h'. In this document, however, a range is an abstract interval
|
||||
which subtends the numeric set.<br>
|
||||
For example, the sequence [-DBL_MAX,DBL_MAX] is the numeric set of the type 'double', and
|
||||
the real interval [abt(-DBL_MAX),abt(DBL_MAX)] is its range.<br>
|
||||
Notice, for instance, that the range of a floating-point type is <i>continuous</i> unlike
|
||||
its numeric set.<br>
|
||||
This definition was chosen because:
|
||||
<li>(a) The discrete set of numeric values is already given by the numeric set.</li>
|
||||
<li>(b) Abstract intervals are easier to compare and overlap since only boundary values
|
||||
need to be considered.</li><br>
|
||||
This definition allows for a concise definition of 'subranged' as given in the last section.<br>
|
||||
The width of a numeric set, as defined, is exactly equivalent to the width of a range.
|
||||
<p></p>
|
||||
<p>The <b>precision</b> of a type is given by the width or density of the numeric set.<br>
|
||||
For integer types, which have density 1, the precision is conceptually equivalent to the range
|
||||
and is determined by the number of bits used in the value representation: The higher the
|
||||
number of bits the bigger the size of the numeric set, the wider the range, and the higher
|
||||
the precision.<br>
|
||||
For floating types, which have density <<1, the precision is given not by the
|
||||
width of the range but by the density. In a typical implementation,
|
||||
the range is determined by the number of bits used in the exponent, and the precision by
|
||||
the number of bits used in the mantissa (giving the maximum number of significant digits
|
||||
that can be exactly represented). The higher the number of exponent bits the
|
||||
wider the range, while the higher the number of mantissa bits, the higher the precision.
|
||||
</p>
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<h2><A NAME="roundoff">Exact, Correctly Rounded and Out-Of-Range Representations</A></h2>
|
||||
<p>Given an abstract value 'V' and a type 'T' with its corresponding range [abt(l),abt(h)]:</p>
|
||||
<p>If <code>V < abt(l)</code> or <code>V > abt(h)</code>, 'V' is <b>not representable</b>
|
||||
(cannot be represented) in the type T, or, equivalently, it's representation in the type 'T'
|
||||
is <b>out of range</b>, or <b>overflows</b>.<br>
|
||||
If <code>V < abt(l)</code>, the <b>overflow is negative</b>.<br>
|
||||
If <code>V > abt(h)</code>, the <b>overflow is positive</b>.
|
||||
</p>
|
||||
<p>If <code>V ≥ abt(l)</code> and <code>V ≤ abt(h)</code>,'V' is <b>representable</b>
|
||||
(can be represented) in the type T, or, equivalently, its representation in the type 'T'
|
||||
is in <b>in range</b>, or <b>does not overflow</b>.</p>
|
||||
<p>Notice that a numeric type, such as a C++ unsigned type, can define that any 'V' does not
|
||||
overflow by always representing not 'V' itself but the abstract value <code>U = [ V % (abt(h)+1) ]</code>,
|
||||
which is always in range.</p>
|
||||
<p>Given an abstract value 'V' represented in the type 'T' as 'v', the <b>roundoff</b> error
|
||||
of the representation is the abstract difference: (abt(v)-V).<br>
|
||||
Notice that a representation is an <i>operation</i>, hence, the roundoff error corresponds to
|
||||
the representation operation and not to the numeric value itself (i.e. numeric values do not
|
||||
have any error themselves)<br>
|
||||
If the roundoff is 0, the representation is <b>exact</b>, and 'V' is <b>exactly representable</b>
|
||||
in the type T.<br>
|
||||
If the roundoff is not 0, the representation is <b>inexact</b>, and 'V' is <b>inexactly representable</b>
|
||||
in the type T.</p>
|
||||
<p>Given an abstract value 'V' representable in a type 'T', there are always two consecutive
|
||||
numeric values of type 'T', 'prev' and 'next', such that <code>abt(prev) ≤ V ≤ abt(next)</code>.
|
||||
These are called the <b>adjacents</b> of 'V' in the type 'T'.<br>
|
||||
If a representation 'v' in a type 'T' -either exact or inexact-, is any of the adjacents of 'V'
|
||||
in that type, that is, if <code>v==prev or v==next</code>, the representation is
|
||||
<b>faithfully rounded</b>. If the choice between 'prev' and 'next'
|
||||
matches a given <b>rounding direction</b>, it is <b>correctly rounded</b>.<br>
|
||||
All exact representations are correctly rounded, but not all inexact representations are. In particular,
|
||||
C++ requires numeric conversions (described below) and the result of arithmetic operations
|
||||
(not covered by this document) to be correctly rounded, but batch operations propagate roundoff, thus
|
||||
final results are usually incorrectly rounded, that is, the numeric value 'r' which is the computed
|
||||
result is neither of the adjacents of the abstract value 'R' which is the theoretical result.<br>
|
||||
Because a correctly rounded representation is always one of adjacents of the abstract value being
|
||||
represented, the roundoff is guaranteed to be at most 1ulp.</p>
|
||||
<P>The following examples summarize the given definitions. Consider:</p>
|
||||
<li>A numeric type 'Int' representing integer numbers with a <i>numeric set</i>: {-2,-1,0,1,2}
|
||||
and <i>range</i>: [-2,2]</li>.
|
||||
<li>A numeric type 'Cardinal' representing integer numbers with a <i>numeric set</i>:
|
||||
{0,1,2,3,4,5,6,7,8,9} and <i>range</i>: [0,9] (no modulo-arithmetic here)</li>.
|
||||
<li>A numeric type 'Real' representing real numbers with a <i>numeric set</i>:
|
||||
{-2.0,-1.5,-1.0,-0.5,-0.0,+0.0,+0.5,+1.0,+1.5,+2.0} and <i>range</i>: [-2.0,+2.0]</li>
|
||||
<li>A numeric type 'Whole' representing real numbers with a <i>numeric set</i>:
|
||||
{-2.0,-1.0,0.0,+1.0,+2.0} and <i>range</i>: [-2.0,+2.0]</li>
|
||||
<p>First, notice that the types 'Real' and 'Whole' both represent real numbers, have the
|
||||
same range, but different precision.</p>
|
||||
<p>The integer number 1 (an abstract value) can be exactly represented in any of these types.<br>
|
||||
The integer number -1 can be exactly represented in 'Int', 'Real' and 'Whole', but cannot
|
||||
be represented in 'Cardinal', yielding negative overflow.<br>
|
||||
The real number 1.5 can be exactly represented in 'Real', and inexactly represented in the
|
||||
other types.<br>
|
||||
If 1.5 is represented as either 1 or 2 in any of the types (except Real), the
|
||||
representation is correctly rounded.<br>
|
||||
If 0.5 is represented as +1.5 in the type 'Real', it is incorrectly rounded.<br>
|
||||
(-2.0,-1.5) are the 'Real' adjacents of any real number in the interval [-2.0,-1.5],
|
||||
yet there are no 'Real' adjacents for x < -2.0, nor for x > +2.0.
|
||||
</p>
|
||||
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<h2><A NAME="stdconv">Standard (numeric) Conversions</A></h2>
|
||||
<P>The C++ language defines <u>Standard Conversions</u> (§4) some of which are
|
||||
conversions between arithmetic types.<br>
|
||||
These are <u>Integral promotions</u> (§4.5), <u>Integral conversions</u> (§4.7),
|
||||
<u>Floating point promotions</u> (§4.6), <u>Floating point conversions</u> (§4.8)
|
||||
and <u>Floating-integral conversions</u> (§4.9).<br>
|
||||
In the sequel, integral and floating point promotions are called <b>arithmetic promotions</b>,
|
||||
and these plus integral, floating-point and floating-integral conversions are called
|
||||
<b>arithmetic conversions</b> (i.e, promotions are conversions).
|
||||
</P>
|
||||
<P>Promotions, both Integral and Floating point, are <i>value-preserving</i>, which means
|
||||
that the typed value is not changed with the conversion.</p>
|
||||
<p>In the sequel, consider a source typed value 's' of type 'S', the source abstract value 'N=abt(s)',
|
||||
a destination type 'T'; and whenever possible, a result typed value 't' of type 'T'.</p>
|
||||
<p>Integer to integer conversions are always defined:<br>
|
||||
If 'T' is unsigned, the abstract value which is effectively represented is not 'N' but
|
||||
'M=[ N % ( abt(h) + 1 ) ]', where 'h' is the highest unsigned typed value of type 'T'.<br>
|
||||
If 'T' is signed and 'N' is not directly representable, the result 't' is
|
||||
<u>implementation-defined</u>, which means that the C++ implementation is required to produce
|
||||
a value 't' even if it is totally unrelated to 's'.</p>
|
||||
<p>Floating to Floating conversions are defined only if 'N' is representable;
|
||||
if it is not, the conversion has <u>undefined behavior.</u><br>
|
||||
If 'N' is exactly representable, 't' is required to be the exact representation.<br>
|
||||
If 'N' is inexactly representable, 't' is required to be one of the two adjacents, with
|
||||
an implementation-defined choice of rounding direction; that is, the conversion is required
|
||||
to be correctly rounded.</p>
|
||||
<p>Floating to Integer conversions represent not 'N' but 'M=trunc(N)', were trunc() is to truncate: i.e.
|
||||
to remove the fractional part, if any.<br>
|
||||
If 'M' is not representable in 'T', the conversion has <u>undefined behavior</u>
|
||||
(unless 'T' is bool, see §4.12).</p>
|
||||
<p>Integer to Floating conversions are always defined.<br>
|
||||
If 'N' is exactly representable, 't' is required to be the exact representation.<br>
|
||||
If 'N' is inexactly representable, 't' is required to be one of the two adjacents, with
|
||||
an implementation-defined choice of rounding direction; that is, the conversion is required
|
||||
to be correctly rounded.</p>
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<h2><A NAME="subranged">Subranged Conversion Direction, Subtype and Supertype</A></h2>
|
||||
<P>Given a source type 'S' and a destination type 'T', there is a <b>conversion direction</b>
|
||||
denoted: <code>'S->T'</code>.<br>
|
||||
For any two ranges the following <i>range relation</i> can be defined: A range
|
||||
'X' can be <i>entirely contained</i> in a range 'Y', in which case it is said that
|
||||
'X' is enclosed by 'Y'.<br>
|
||||
Formally: R(S) is <b>enclosed</b> by R(T) iif (R(S) intersection R(T)) == R(S).</P>
|
||||
<P>If the source type range, R(S), is <i>not enclosed</i> in the target type range, R(T);
|
||||
that is, if (R(S) & R(T)) != R(S), the conversion direction is said to be <b>subranged</b>,
|
||||
which means that R(S) is not entirely contained in R(T) and therefore there is
|
||||
some portion of the source range which falls outside the target range. In other words,
|
||||
if a conversion direction S->T is subranged, there are values in S which cannot be represented
|
||||
in T because they are out of range.<br>
|
||||
Notice that for S->T, the adjective subranged applies to 'T'.</p>
|
||||
<p>Examples:<br>
|
||||
Given the following numeric types all representing real numbers:<br>
|
||||
<br>
|
||||
X with numeric set {-2.0,-1.0,0.0,+1.0,+2.0} and range [-2.0,+2.0]<br>
|
||||
Y with numeric set {-2.0,-1.5,-1.0,-0.5,0.0,+0.5,+1.0,+1.5,+2.0} and range [-2.0,+2.0]<br>
|
||||
Z with numeric set {-1.0,0.0,+1.0} and range [-1.0,+1.0]<br>
|
||||
<br>
|
||||
For:<br>
|
||||
<br>
|
||||
(a) X->Y:
|
||||
<blockquote>
|
||||
R(X) & R(Y) == R(X), then X->Y is not subranged.
|
||||
Thus, all values of type X are representable in the type Y.
|
||||
</blockquote>
|
||||
(b) Y->X:
|
||||
<blockquote>
|
||||
R(Y) & R(X) == R(Y), then Y->X is not subranged.
|
||||
Thus, all values of type Y are representable in the type X, but in this case, some values
|
||||
are <i>inexactly</i> representable (all the halves).<br>
|
||||
(note: it is to permit this case that a range is an interval of abstract values
|
||||
and not an interval of typed values)
|
||||
</blockquote>
|
||||
(b) X->Z:
|
||||
<blockquote>
|
||||
R(X) & R(Z) != R(X), then X->Z is subranged.
|
||||
Thus, some values of type X are not representable in the type Z, they fall out of range
|
||||
(-2.0 and +2.0)
|
||||
</blockquote>
|
||||
<p></p>
|
||||
<p>It is possible that R(S) is not enclosed by R(T), while neither is R(T) enclosed
|
||||
by R(S); for example, UNSIG=[0,255] is not enclosed by SIG=[-128,127]; neither is SIG
|
||||
enclosed by UNSIG.<br>
|
||||
This implies that is possible that a conversion direction is subranged both
|
||||
ways. This occurs when a mixture of signed/unsigned types are involved and indicates
|
||||
that in both directions there are values which can fall out of range.</P>
|
||||
<P>Given the range relation (subranged or not) of a conversion direction S->T,
|
||||
it is possible to classify 'S' and 'T' as <b>supertype</b> and <b>subtype</b>:<br>
|
||||
If the conversion is subranged, which means that 'T' cannot represent all possible values of type 'S',
|
||||
'S' is the supertype and 'T' the subtype; otherwise, 'T' is the supertype and 'S' the subtype.<br>
|
||||
<br>
|
||||
For example:<br>
|
||||
R(float)=[-FLT_MAX,FLT_MAX] and R(double)=[-DBL_MAX,DBL_MAX].<br>
|
||||
If FLT_MAX < DBL_MAX:<br>
|
||||
'double->float' is subranged and supertype=double, subtype=float.<br>
|
||||
'float->double' is not subranged and supertype=double, subtype=float.<br>
|
||||
Notice that while 'double->float' is subranged, 'float->double' is not,
|
||||
which yields the same supertype,subtype for both directions.<br>
|
||||
<br>
|
||||
Now consider:<br>
|
||||
R(int)=[INT_MIN,INT_MAX] and R(unsigned int)=[0,UINT_MAX].<br>
|
||||
A C++ implementation is required to have UINT_MAX > INT_MAX (§3.9/3), so:<br>
|
||||
'int->unsigned' is subranged (negative values fall out of range) and supertype=int, subtype=unsigned.<br>
|
||||
'unsigned->int' is <em>also</em> subranged (high positive values fall out of range)
|
||||
and supertype=unsigned, subtype=int.<br>
|
||||
In this case, the conversion is subranged in both directions and the supertype,subtype pairs
|
||||
are not invariant (under inversion of direction). This indicates that none of the types can
|
||||
represent all the values of the other.</p>
|
||||
<p>When the supertype is the same for both 'S->T' and 'T->S', it is effectively indicating
|
||||
a type which can represent all the values of the subtype.<br>
|
||||
Consequently, if a conversion X->Y is not subranged, but the opposite (Y->X)
|
||||
is, so that the supertype is always 'Y', it is said that the direction X->Y
|
||||
is <b>correctly rounded value preserving</b>, meaning that all such conversions
|
||||
are guaranteed to produce results in range and correctly rounded (even if inexact).<br>
|
||||
For example, all integer to floating conversions are correctly rounded value preserving.
|
||||
</p>
|
||||
<HR>
|
||||
<P>Back to <A HREF="index.html">Numeric Conversion library index</A></P>
|
||||
<HR>
|
||||
<P>Revised 23 June 2004</P>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</body>
|
||||
</HTML>
|
||||
@@ -13,17 +13,17 @@
|
||||
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|
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@@ -73,7 +73,7 @@
|
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<span class="special">};</span>
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</pre>
|
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<a name="boost_numericconversion.bounds___traits_class.traits_class_bounds_n_.members"></a><h5>
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@@ -153,11 +153,15 @@
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="right"><div class="copyright-footer">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal<p>
|
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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<div class="toc"><dl>
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int_float_mixture_enum</a></span></dt>
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<dt><span class="section"><a href="conversion_traits___traits_class.html#boost_numericconversion.conversion_traits___traits_class.types.enumeration_sign_mixture_enum">enumeration
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sign_mixture_enum</a></span></dt>
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<dt><span class="section"><a href="conversion_traits___traits_class.html#boost_numericconversion.conversion_traits___traits_class.types.template_class_int_float_mixture__">template
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class int_float_mixture<></a></span></dt>
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<dt><span class="section"><a href="conversion_traits___traits_class.html#boost_numericconversion.conversion_traits___traits_class.types.template_class_sign_mixture__">template
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class sign_mixture<></a></span></dt>
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<dt><span class="section"><a href="conversion_traits___traits_class.html#boost_numericconversion.conversion_traits___traits_class.types.template_class_udt_builtin_mixture__">template
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class udt_builtin_mixture<></a></span></dt>
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<dt><span class="section"><a href="conversion_traits___traits_class.html#boost_numericconversion.conversion_traits___traits_class.types.template_class_is_subranged__">template
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class is_subranged<></a></span></dt>
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<dt><span class="section"><a href="conversion_traits___traits_class.html#boost_numericconversion.conversion_traits___traits_class.types.template_class_conversion_traits__">template
|
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class conversion_traits<></a></span></dt>
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</dl></dd>
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<dt><span class="section"><a href="conversion_traits___traits_class.html#boost_numericconversion.conversion_traits___traits_class.examples">Examples</a></span></dt>
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@@ -555,11 +537,15 @@
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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@@ -401,7 +401,7 @@
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<a name="numeric_conversion_converter_internal"></a><p>
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|
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<a name="boost_numericconversion.converter___function_object.member_functions.internal_member_functions"></a><h5>
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Member Functions</a>
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@@ -497,11 +497,15 @@ float_to_float |--> subranged |--> ( s >= S(LowestT) ) && (
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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<a accesskey="p" href="../index.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="converter___function_object.html"><img src="../images/next.png" alt="Next"></a>
|
||||
<a accesskey="p" href="../index.html"><img src="../../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="converter___function_object.html"><img src="../../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section" lang="en">
|
||||
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
|
||||
@@ -179,35 +179,42 @@
|
||||
<dl>
|
||||
<dt><span class="term"><span class="underline">signed integer
|
||||
types</span> (§3.9.1/2):</span></dt>
|
||||
<dd>
|
||||
<code class="computeroutput"><span class="special">{</span><span class="keyword">signed</span>
|
||||
<span class="keyword">char</span><span class="special">,</span>
|
||||
<span class="keyword">signed</span> <span class="keyword">short</span>
|
||||
<span class="keyword">int</span><span class="special">,</span> <span class="keyword">signed</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">signed</span> <span class="keyword">long</span> <span class="keyword">int</span><span class="special">}</span></code> Can be used to represent general integer
|
||||
numbers (both negative and positive).
|
||||
</dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="special">{</span><span class="keyword">signed</span>
|
||||
<span class="keyword">char</span><span class="special">,</span>
|
||||
<span class="keyword">signed</span> <span class="keyword">short</span>
|
||||
<span class="keyword">int</span><span class="special">,</span>
|
||||
<span class="keyword">signed</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">signed</span> <span class="keyword">long</span> <span class="keyword">int</span><span class="special">}</span></code> Can be used to represent general integer
|
||||
numbers (both negative and positive).
|
||||
</p></dd>
|
||||
<dt><span class="term"><span class="underline">unsigned integer
|
||||
types</span> (§3.9.1/3):</span></dt>
|
||||
<dd>
|
||||
<code class="computeroutput"><span class="special">{</span><span class="keyword">unsigned</span>
|
||||
<span class="keyword">char</span><span class="special">,</span>
|
||||
<span class="keyword">unsigned</span> <span class="keyword">short</span>
|
||||
<span class="keyword">int</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="keyword">int</span><span class="special">}</span></code> Can be used to represent positive integer
|
||||
numbers with modulo-arithmetic.
|
||||
</dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="special">{</span><span class="keyword">unsigned</span>
|
||||
<span class="keyword">char</span><span class="special">,</span>
|
||||
<span class="keyword">unsigned</span> <span class="keyword">short</span>
|
||||
<span class="keyword">int</span><span class="special">,</span>
|
||||
<span class="keyword">unsigned</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="keyword">int</span><span class="special">}</span></code> Can be used to represent positive integer
|
||||
numbers with modulo-arithmetic.
|
||||
</p></dd>
|
||||
<dt><span class="term"><span class="underline">floating-point
|
||||
types</span> (§3.9.1/8):</span></dt>
|
||||
<dd>
|
||||
<code class="computeroutput"><span class="special">{</span><span class="keyword">float</span><span class="special">,</span><span class="keyword">double</span><span class="special">,</span><span class="keyword">long</span> <span class="keyword">double</span><span class="special">}</span></code> Can be used to represent real numbers.
|
||||
</dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="special">{</span><span class="keyword">float</span><span class="special">,</span><span class="keyword">double</span><span class="special">,</span><span class="keyword">long</span> <span class="keyword">double</span><span class="special">}</span></code>
|
||||
Can be used to represent real numbers.
|
||||
</p></dd>
|
||||
<dt><span class="term"><span class="underline">integral or
|
||||
integer types</span> (§3.9.1/7):</span></dt>
|
||||
<dd><code class="computeroutput"><span class="special">{{</span><span class="keyword">signed</span>
|
||||
<span class="identifier">integers</span><span class="special">},{</span><span class="keyword">unsigned</span> <span class="identifier">integers</span><span class="special">},</span> <span class="keyword">bool</span><span class="special">,</span> <span class="keyword">char</span> <span class="keyword">and</span> <span class="keyword">wchar_t</span><span class="special">}</span></code></dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="special">{{</span><span class="keyword">signed</span>
|
||||
<span class="identifier">integers</span><span class="special">},{</span><span class="keyword">unsigned</span> <span class="identifier">integers</span><span class="special">},</span> <span class="keyword">bool</span><span class="special">,</span> <span class="keyword">char</span> <span class="keyword">and</span> <span class="keyword">wchar_t</span><span class="special">}</span></code>
|
||||
</p></dd>
|
||||
<dt><span class="term"><span class="underline">arithmetic
|
||||
types</span> (§3.9.1/8):</span></dt>
|
||||
<dd><code class="computeroutput"><span class="special">{{</span><span class="identifier">integer</span>
|
||||
<span class="identifier">types</span><span class="special">},{</span><span class="identifier">floating</span> <span class="identifier">types</span><span class="special">}}</span></code></dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="special">{{</span><span class="identifier">integer</span>
|
||||
<span class="identifier">types</span><span class="special">},{</span><span class="identifier">floating</span> <span class="identifier">types</span><span class="special">}}</span></code>
|
||||
</p></dd>
|
||||
</dl>
|
||||
</div>
|
||||
<p>
|
||||
@@ -234,31 +241,23 @@
|
||||
</p>
|
||||
<div class="note"><table border="0" summary="Note">
|
||||
<tr>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../doc/html/images/note.png"></td>
|
||||
<th align="left">Note</th>
|
||||
</tr>
|
||||
<tr><td align="left" valign="top">
|
||||
<p>
|
||||
</p>
|
||||
Always remember that unsigned types, unlike signed types, have modulo-arithmetic;
|
||||
that is, they do not overflow. This means that:
|
||||
</p>
|
||||
<p>
|
||||
Always remember that unsigned types, unlike signed types, have modulo-arithmetic;
|
||||
that is, they do not overflow. This means that:
|
||||
</p>
|
||||
<p>
|
||||
</p>
|
||||
<p>
|
||||
<span class="bold"><strong>-</strong></span> Always be extra careful when mixing
|
||||
signed/unsigned types
|
||||
</p>
|
||||
<p>
|
||||
</p>
|
||||
<p>
|
||||
<span class="bold"><strong>-</strong></span> Use unsigned types only when you need
|
||||
modulo arithmetic or very very large numbers. Don't use unsigned types
|
||||
just because you intend to deal with positive values only (you can do
|
||||
this with signed types as well).
|
||||
</p>
|
||||
<span class="bold"><strong>-</strong></span> Always be extra careful when mixing
|
||||
signed/unsigned types
|
||||
</p>
|
||||
<p>
|
||||
<span class="bold"><strong>-</strong></span> Use unsigned types only when you need
|
||||
modulo arithmetic or very very large numbers. Don't use unsigned types
|
||||
just because you intend to deal with positive values only (you can do this
|
||||
with signed types as well).
|
||||
</p>
|
||||
</td></tr>
|
||||
</table></div>
|
||||
@@ -875,37 +874,31 @@
|
||||
<p class="title"><b></b></p>
|
||||
<dl>
|
||||
<dt><span class="term">(a) X->Y:</span></dt>
|
||||
<dd>
|
||||
<code class="computeroutput"><span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span> <span class="special">&</span>
|
||||
<span class="identifier">R</span><span class="special">(</span><span class="identifier">Y</span><span class="special">)</span> <span class="special">==</span>
|
||||
<span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span></code>, then
|
||||
<code class="computeroutput"><span class="identifier">X</span><span class="special">-></span><span class="identifier">Y</span></code> is not subranged. Thus, all values
|
||||
of type <code class="computeroutput"><span class="identifier">X</span></code> are representable
|
||||
in the type <code class="computeroutput"><span class="identifier">Y</span></code>.
|
||||
</dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span> <span class="special">&</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">Y</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span></code>,
|
||||
then <code class="computeroutput"><span class="identifier">X</span><span class="special">-></span><span class="identifier">Y</span></code> is not subranged. Thus, all values
|
||||
of type <code class="computeroutput"><span class="identifier">X</span></code> are representable
|
||||
in the type <code class="computeroutput"><span class="identifier">Y</span></code>.
|
||||
</p></dd>
|
||||
<dt><span class="term">(b) Y->X:</span></dt>
|
||||
<dd>
|
||||
<code class="computeroutput"><span class="identifier">R</span><span class="special">(</span><span class="identifier">Y</span><span class="special">)</span> <span class="special">&</span>
|
||||
<span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span> <span class="special">==</span>
|
||||
<span class="identifier">R</span><span class="special">(</span><span class="identifier">Y</span><span class="special">)</span></code>, then
|
||||
<code class="computeroutput"><span class="identifier">Y</span><span class="special">-></span><span class="identifier">X</span></code> is not subranged. Thus, all values
|
||||
of type <code class="computeroutput"><span class="identifier">Y</span></code> are representable
|
||||
in the type <code class="computeroutput"><span class="identifier">X</span></code>, but in this
|
||||
case, some values are <span class="emphasis"><em>inexactly</em></span> representable (all
|
||||
the halves). (note: it is to permit this case that a range is an interval
|
||||
of abstract values and not an interval of typed values)
|
||||
</dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="identifier">R</span><span class="special">(</span><span class="identifier">Y</span><span class="special">)</span> <span class="special">&</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">Y</span><span class="special">)</span></code>,
|
||||
then <code class="computeroutput"><span class="identifier">Y</span><span class="special">-></span><span class="identifier">X</span></code> is not subranged. Thus, all values
|
||||
of type <code class="computeroutput"><span class="identifier">Y</span></code> are representable
|
||||
in the type <code class="computeroutput"><span class="identifier">X</span></code>, but in
|
||||
this case, some values are <span class="emphasis"><em>inexactly</em></span> representable
|
||||
(all the halves). (note: it is to permit this case that a range is an
|
||||
interval of abstract values and not an interval of typed values)
|
||||
</p></dd>
|
||||
<dt><span class="term">(b) X->Z:</span></dt>
|
||||
<dd>
|
||||
<code class="computeroutput"><span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span> <span class="special">&</span>
|
||||
<span class="identifier">R</span><span class="special">(</span><span class="identifier">Z</span><span class="special">)</span> <span class="special">!=</span>
|
||||
<span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span></code>, then
|
||||
<code class="computeroutput"><span class="identifier">X</span><span class="special">-></span><span class="identifier">Z</span></code> is subranged. Thus, some values of
|
||||
type <code class="computeroutput"><span class="identifier">X</span></code> are not representable
|
||||
in the type <code class="computeroutput"><span class="identifier">Z</span></code>, they fall
|
||||
out of range <code class="computeroutput"><span class="special">(-</span><span class="number">2.0</span>
|
||||
<span class="keyword">and</span> <span class="special">+</span><span class="number">2.0</span><span class="special">)</span></code>.
|
||||
</dd>
|
||||
<dd><p>
|
||||
<code class="computeroutput"><span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span> <span class="special">&</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">Z</span><span class="special">)</span> <span class="special">!=</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span></code>,
|
||||
then <code class="computeroutput"><span class="identifier">X</span><span class="special">-></span><span class="identifier">Z</span></code> is subranged. Thus, some values of
|
||||
type <code class="computeroutput"><span class="identifier">X</span></code> are not representable
|
||||
in the type <code class="computeroutput"><span class="identifier">Z</span></code>, they fall
|
||||
out of range <code class="computeroutput"><span class="special">(-</span><span class="number">2.0</span>
|
||||
<span class="keyword">and</span> <span class="special">+</span><span class="number">2.0</span><span class="special">)</span></code>.
|
||||
</p></dd>
|
||||
</dl>
|
||||
</div>
|
||||
<p>
|
||||
@@ -1007,11 +1000,15 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><small>Copyright © 2004 -2007 Fernando Luis Cacciola Carballal</small></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal<p>
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
|
||||
</p>
|
||||
</div></td>
|
||||
</tr></table>
|
||||
<hr>
|
||||
<div class="spirit-nav">
|
||||
<a accesskey="p" href="../index.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="converter___function_object.html"><img src="../images/next.png" alt="Next"></a>
|
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|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
@@ -13,17 +13,17 @@
|
||||
and Acknowledgments">
|
||||
</head>
|
||||
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
|
||||
<table cellpadding="2" width="100%">
|
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<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td>
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<td align="center"><a href="../../../index.htm">Home</a></td>
|
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<td align="center"><a href="../libraries.html">Libraries</a></td>
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<a accesskey="p" href="numeric_converter_policy_classes.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="../numeric_conversion/history_and_acknowledgments.html"><img src="../images/next.png" alt="Next"></a>
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<a accesskey="p" href="numeric_converter_policy_classes.html"><img src="../../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="../numeric_conversion/history_and_acknowledgments.html"><img src="../../../../../../doc/html/images/next.png" alt="Next"></a>
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</div>
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<div class="section" lang="en">
|
||||
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
|
||||
@@ -174,11 +174,15 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><small>Copyright © 2004 -2007 Fernando Luis Cacciola Carballal</small></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal<p>
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
|
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</p>
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</div></td>
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</tr></table>
|
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<hr>
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<div class="spirit-nav">
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<a accesskey="p" href="numeric_converter_policy_classes.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="../numeric_conversion/history_and_acknowledgments.html"><img src="../images/next.png" alt="Next"></a>
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<a accesskey="p" href="numeric_converter_policy_classes.html"><img src="../../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="../numeric_conversion/history_and_acknowledgments.html"><img src="../../../../../../doc/html/images/next.png" alt="Next"></a>
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</body>
|
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</html>
|
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|
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@@ -13,17 +13,17 @@
|
||||
numeric_cast<>">
|
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</head>
|
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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<table cellpadding="2" width="100%">
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<td align="center"><a href="http://www.boost.org/people/people.htm">People</a></td>
|
||||
<td align="center"><a href="http://www.boost.org/more/faq.htm">FAQ</a></td>
|
||||
<td align="center"><a href="../../../../../../more/index.htm">More</a></td>
|
||||
</tr></table>
|
||||
<hr>
|
||||
<div class="spirit-nav">
|
||||
<a accesskey="p" href="conversion_traits___traits_class.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="improved_numeric_cast__.html"><img src="../images/next.png" alt="Next"></a>
|
||||
<a accesskey="p" href="conversion_traits___traits_class.html"><img src="../../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="improved_numeric_cast__.html"><img src="../../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section" lang="en">
|
||||
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
|
||||
@@ -165,28 +165,22 @@
|
||||
</p>
|
||||
<div class="important"><table border="0" summary="Important">
|
||||
<tr>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../images/important.png"></td>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../../doc/html/images/important.png"></td>
|
||||
<th align="left">Important</th>
|
||||
</tr>
|
||||
<tr><td align="left" valign="top">
|
||||
<p>
|
||||
</p>
|
||||
<p>
|
||||
<span class="bold"><strong>RELEASE NOTE for 1.33</strong></span> Previous to boost
|
||||
version 1.33, the exception class <code class="computeroutput"><span class="identifier">bad_numeric_cast</span></code>
|
||||
was named <code class="computeroutput"><span class="identifier">bad_numeric_conversion</span></code>.
|
||||
However, in 1.33, the old function <code class="computeroutput"><span class="identifier">numeric_cast</span><span class="special"><></span></code> from <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code>
|
||||
was completly replaced by the new <code class="computeroutput"><span class="identifier">numeric_cast</span><span class="special"><></span></code> in <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">numeric</span><span class="special">/</span><span class="identifier">conversion</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code>
|
||||
(and <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code> is including <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">numeric</span><span class="special">/</span><span class="identifier">conversion</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code>
|
||||
now). That old function which existed in boost for quite some time used
|
||||
the <code class="computeroutput"><span class="identifier">bad_numeric_cast</span></code>
|
||||
as its exception type so I decided to avoid backward compatibility problems
|
||||
by adopting it (guessing that the user base for the old code is wider
|
||||
than for the new code).
|
||||
</p>
|
||||
<p>
|
||||
</p>
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top"><p>
|
||||
<span class="bold"><strong>RELEASE NOTE for 1.33</strong></span> Previous to boost
|
||||
version 1.33, the exception class <code class="computeroutput"><span class="identifier">bad_numeric_cast</span></code>
|
||||
was named <code class="computeroutput"><span class="identifier">bad_numeric_conversion</span></code>.
|
||||
However, in 1.33, the old function <code class="computeroutput"><span class="identifier">numeric_cast</span><span class="special"><></span></code> from <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code>
|
||||
was completly replaced by the new <code class="computeroutput"><span class="identifier">numeric_cast</span><span class="special"><></span></code> in <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">numeric</span><span class="special">/</span><span class="identifier">conversion</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code>
|
||||
(and <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code> is including <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">numeric</span><span class="special">/</span><span class="identifier">conversion</span><span class="special">/</span><span class="identifier">cast</span><span class="special">.</span><span class="identifier">hpp</span></code>
|
||||
now). That old function which existed in boost for quite some time used
|
||||
the <code class="computeroutput"><span class="identifier">bad_numeric_cast</span></code> as
|
||||
its exception type so I decided to avoid backward compatibility problems
|
||||
by adopting it (guessing that the user base for the old code is wider than
|
||||
for the new code).
|
||||
</p></td></tr>
|
||||
</table></div>
|
||||
</div>
|
||||
<a name="numeric_conversion_policy_float_to_int_rounder"></a><p>
|
||||
@@ -226,20 +220,14 @@
|
||||
</p>
|
||||
<div class="note"><table border="0" summary="Note">
|
||||
<tr>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../doc/html/images/note.png"></td>
|
||||
<th align="left">Note</th>
|
||||
</tr>
|
||||
<tr><td align="left" valign="top">
|
||||
<p>
|
||||
</p>
|
||||
<p>
|
||||
These classes are not intended to be general purpose rounding functions
|
||||
but specific policies for <code class="computeroutput"><span class="identifier">converter</span><span class="special"><></span></code>. This is why they are not function
|
||||
objects.
|
||||
</p>
|
||||
<p>
|
||||
</p>
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top"><p>
|
||||
These classes are not intended to be general purpose rounding functions
|
||||
but specific policies for <code class="computeroutput"><span class="identifier">converter</span><span class="special"><></span></code>. This is why they are not function
|
||||
objects.
|
||||
</p></td></tr>
|
||||
</table></div>
|
||||
<pre class="programlisting">
|
||||
<span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">numeric</span> <span class="special">{</span>
|
||||
@@ -299,7 +287,7 @@
|
||||
<span class="special">}</span> <span class="special">}</span> <span class="comment">// namespace numeric, namespace boost
|
||||
</span></pre>
|
||||
<a name="boost_numericconversion.numeric_converter_policy_classes.policy_float2introunder.math_functions_used_by_the_rounder_policies"></a><h5>
|
||||
<a name="id2633882"></a>
|
||||
<a name="id2634042"></a>
|
||||
<a href="numeric_converter_policy_classes.html#boost_numericconversion.numeric_converter_policy_classes.policy_float2introunder.math_functions_used_by_the_rounder_policies">Math
|
||||
Functions used by the rounder policies</a>
|
||||
</h5>
|
||||
@@ -422,11 +410,15 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><small>Copyright © 2004 -2007 Fernando Luis Cacciola Carballal</small></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal<p>
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
|
||||
</p>
|
||||
</div></td>
|
||||
</tr></table>
|
||||
<hr>
|
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<div class="spirit-nav">
|
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|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
+17
-13
@@ -13,17 +13,17 @@
|
||||
traits class">
|
||||
</head>
|
||||
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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<table cellpadding="2" width="100%">
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<table cellpadding="2" width="100%"><tr>
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<a accesskey="p" href="converter___function_object.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="bounds___traits_class.html"><img src="../images/next.png" alt="Next"></a>
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<a accesskey="p" href="converter___function_object.html"><img src="../../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="bounds___traits_class.html"><img src="../../../../../../doc/html/images/next.png" alt="Next"></a>
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</div>
|
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<div class="section" lang="en">
|
||||
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
|
||||
@@ -86,7 +86,7 @@
|
||||
special semantics</a>
|
||||
</h3></div></div></div>
|
||||
<a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.conversion_traits"></a><h5>
|
||||
<a name="id2625220"></a>
|
||||
<a name="id2625386"></a>
|
||||
<a href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.conversion_traits">Conversion
|
||||
Traits</a>
|
||||
</h5>
|
||||
@@ -130,7 +130,7 @@
|
||||
above.
|
||||
</p>
|
||||
<a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.range_checking"></a><h5>
|
||||
<a name="id2625640"></a>
|
||||
<a name="id2625806"></a>
|
||||
<a href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.range_checking">Range
|
||||
Checking</a>
|
||||
</h5>
|
||||
@@ -183,11 +183,15 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><small>Copyright © 2004 -2007 Fernando Luis Cacciola Carballal</small></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal<p>
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
|
||||
</p>
|
||||
</div></td>
|
||||
</tr></table>
|
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<hr>
|
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<div class="spirit-nav">
|
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<a accesskey="p" href="converter___function_object.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="bounds___traits_class.html"><img src="../images/next.png" alt="Next"></a>
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</html>
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|
||||
Executable → Regular
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+13
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@@ -8,16 +8,16 @@
|
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<link rel="next" href="boost_numericconversion/definitions.html" title="Definitions">
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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<div class="chapter" lang="en">
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<div class="titlepage"><div>
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<div><h2 class="title">
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@@ -27,7 +27,7 @@
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</h3></div></div>
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<div><p class="copyright">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal</p></div>
|
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<div><div class="legalnotice">
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<a name="id2604797"></a><p>
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<a name="id2604942"></a><p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
|
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</p>
|
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@@ -178,10 +178,10 @@
|
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</p>
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"><small><p>Last revised: June 04, 2007 at 03:08:57 GMT</p></small></td>
|
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<td align="right"><small></small></td>
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<td align="left"><p><small>Last revised: February 12, 2008 at 22:56:38 GMT</small></p></td>
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</body>
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</html>
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@@ -10,17 +10,17 @@
|
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and Acknowledgments">
|
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</head>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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<table cellpadding="2" width="100%">
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<div class="section" lang="en">
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
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@@ -73,11 +73,15 @@
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"></td>
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<td align="right"><small>Copyright © 2004 -2007 Fernando Luis Cacciola Carballal</small></td>
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<td align="right"><div class="copyright-footer">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal<p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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</p>
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</div></td>
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</tr></table>
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<hr>
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@@ -31,7 +31,7 @@
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and Acknowledgments</a>
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</h2></div></div></div>
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<a name="numeric_conversion.history_and_acknowledgments.pre_formal_review"></a><h4>
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<a href="history_and_acknowledgments.html#numeric_conversion.history_and_acknowledgments.pre_formal_review">Pre-formal
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review</a>
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</h4>
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@@ -67,7 +67,7 @@
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</li>
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</ul></div>
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<a name="numeric_conversion.history_and_acknowledgments.post_formal_review"></a><h4>
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<a href="history_and_acknowledgments.html#numeric_conversion.history_and_acknowledgments.post_formal_review">Post-formal
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review</a>
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@@ -85,11 +85,15 @@
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"></td>
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<td align="right"><small>Copyright © 2004 -2007 Fernando Luis Cacciola Carballal</small></td>
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<td align="right"><div class="copyright-footer">Copyright © 2004 -2007 Fernando Luis Cacciola Carballal<p>
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
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file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000ff" VLINK="#800080">
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<TH VALIGN="top" WIDTH="300">
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<H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277"
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ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH>
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<TH VALIGN="top">
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<H1 ALIGN="center">Boost Numeric Conversion Library</H1> </TH>
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</TR>
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</TABLE>
|
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<HR>
|
||||
<table border="0" cellpadding="0" width="100%">
|
||||
<tr>
|
||||
<td width="50%" valign="top"><font size="4">This Document</font><br><br>
|
||||
<a href="#Overview">Overview</a><br>
|
||||
<a href="#Ack">History and Acknowledgments</a><br>
|
||||
<a href="#Ref">Bibliography</a><br>
|
||||
</td>
|
||||
<td width="50%"><font size="4">Other Documents</font><br><br>
|
||||
<A HREF="definitions.html">Definitions</A><br>
|
||||
<A HREF="converter.html"><code>converter<></code> function object</A><br>
|
||||
<A HREF="requirements.html">Type Requirements and User-defined-types support</A><br>
|
||||
<A HREF="bounds.html"><code>bounds<></code> traits class</A><br>
|
||||
<A HREF="conversion_traits.html"><code>conversion_traits<></code> traits class</A><br>
|
||||
<A HREF="converter_policies.html">Numeric Converter Policy Classes</A><br>
|
||||
<A HREF="numeric_cast.html">Improved numeric_cast<></A><br>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<hr>
|
||||
<H2><A NAME="Overview"></A>Overview</H2>
|
||||
<P>The Boost Numeric Conversion library is a collection of tools to describe and perform
|
||||
conversions between values of different <a href="definitions.html#numtypes">numeric types</a>.</p>
|
||||
<p>The library includes a special alternative for a subset of <code>std::numeric_limits<></code>,
|
||||
the <A HREF="bounds.html"><code>bounds<></code></A> traits class, which provides
|
||||
a consistent way to obtain the <a href="definitions.html#range">boundary</a> values for the
|
||||
<a href="definitions.html#range">range</a> of a numeric type.</p>
|
||||
<p>It also includes a set of <A HREF="conversion_traits.html">trait classes</A> which
|
||||
describes the compile-time properties of a conversion from a source to a target
|
||||
numeric type. Both <a href="definitions.html#stdtypes">arithmetic</a> and <a href="definitions.html#numtypes">user-defined
|
||||
numeric types</a> can be used.</p>
|
||||
<p>A policy-based <A HREF="converter.html">converter</A> object which uses <code>conversion_traits</code>
|
||||
to select an optimized implementation is supplied.
|
||||
Such implementation uses an optimal range checking code suitable for the source/target combination.<br>
|
||||
The converter's out-of-range behavior can be customized via an <A HREF="converter_policies.html#oh">OverflowHandler</A>
|
||||
policy.<br>
|
||||
For floating-point to integral conversions, the rounding mode can be selected via
|
||||
the <A HREF="converter_policies.html#f2i">Float2IntRounder</A> policy.<br>
|
||||
A custom low-level conversion routine (for UDTs for instance) can be passed
|
||||
via a <A HREF="converter_policies.html#rawc">RawConverter</A> policy.<br>
|
||||
The optimized automatic range-checking logic can be overridden via a <A HREF="converter_policies.html#rc">UserRangeChecker</A>
|
||||
policy.</p>
|
||||
<hr>
|
||||
<H2><A NAME="Ack"></A>History and Acknowledgments</H2>
|
||||
<p>Pre-formal review:</p>
|
||||
<blockquote>
|
||||
<p>Kevlin Henney, with help from David Abrahams and Beman Dawes, originally contributed
|
||||
the previous version of numeric_cast<> which already presented the idea of a runtime range check.<br>
|
||||
Later, Eric Ford, Kevin Lynch and the author spotted some genericity problems
|
||||
with that numeric_cast<> which prevented it from being used in a generic
|
||||
layer of math functions.<br>
|
||||
An improved numeric_cast<> which properly handled all combinations of arithmetic types was presented.<br>
|
||||
David Abrahams and Beman Dawes acknowledged the need of an improved version
|
||||
of numeric_cast<> and supported the submission as originally laid out.
|
||||
Daryl Walker and Darin Adler made some important comments and proposed fixes
|
||||
to the original submission.</p>
|
||||
<p>Special thanks go to Björn Karlsoon who helped the author considerably. Having
|
||||
found the problems with numeric_cast<> himself, he revised very carefully
|
||||
the original submission and spot a subtle bug in the range checking implementation.
|
||||
He also wrote part of this documentation and proof-read and corrected other
|
||||
parts. And most importantly: the features now presented here in this library
|
||||
evolved from the original submission as a result of the useful private communications
|
||||
between Björn and the author.</p>
|
||||
</blockquote>
|
||||
<p>Post-formal review:</p>
|
||||
<p>Guillaume Melquiond spoted some documentation and code issues, particularly about rounding conversions.<br>
|
||||
The following people contributed an important review of the design, documentation and code: Kevin Lynch, Thorsten Ottosen, Paul Bristow,
|
||||
Daryle Walker, Jhon Torjo, Eric Ford, Gennadiy Rozental.
|
||||
</p>
|
||||
<hr>
|
||||
<H2><A NAME="Ref"></A>Bibliography</H2>
|
||||
<ul>
|
||||
<li>Standard Documents:
|
||||
<ol>
|
||||
<li>ISO/IEC 14882:98 (C++98 Standard)</li>
|
||||
<li>ISO/IEC 9899:1999 (C99 Standard)</li>
|
||||
<li>ISO/IEC 10967-1 (Language Independent Arithmetic (LIA), Part I, 1994)</li>
|
||||
<li>ISO/IEC 2382-1:1993 (Information Technology - Vocabulary - Part I: Fundamental Terms)</li>
|
||||
<li>ANSI/IEEE 754-1985 [and IEC 60559:1989] (Binary floating-point)</li>
|
||||
<li>ANSI/IEEE 854-1988 (Radix Independent floating-point)</li>
|
||||
<li>ANSI X3/TR-1-82 (Dictionary for Information Processing Systems)</li>
|
||||
<li><a href="http://anubis.dkuug.dk/JTC1/SC22/WG14/www/docs/n753.htm">ISO/IEC JTC1/SC22/WG14/N753</a> C9X Revision Proposal: LIA-1 Binding: Rationale</li>
|
||||
</ol>
|
||||
</li>
|
||||
<li>Papers:
|
||||
<ol>
|
||||
<li>David Goldberg <A href="http://citeseer.ist.psu.edu/goldberg91what.html">
|
||||
What Every Computer Scientist Should Know About Floating-Point Arithmetic</A></li>
|
||||
<li><A href="http://www.cs.berkeley.edu/~wkahan/">Prof. William Kahan</A> papers on floating-point.</li>
|
||||
</ol>
|
||||
</li>
|
||||
</ul>
|
||||
<HR>
|
||||
<P>Revised 23 June 2004</P>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</body>
|
||||
</HTML>
|
||||
@@ -1,134 +0,0 @@
|
||||
<HTML>
|
||||
<HEAD>
|
||||
<LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css">
|
||||
<TITLE>Boost Numeric Conversion Library - numeric_cast</TITLE>
|
||||
</HEAD>
|
||||
<BODY BGCOLOR="#FFFFFF" TEXT="#000000">
|
||||
<TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%"
|
||||
SUMMARY="header">
|
||||
<TR>
|
||||
<TH VALIGN="top" WIDTH="300">
|
||||
<H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277"
|
||||
ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH>
|
||||
<TH VALIGN="top">
|
||||
<H1 ALIGN="center">Boost Numeric Conversion Library</H1>
|
||||
<H1><A HREF="http://www.boost.org">Header </A><A
|
||||
HREF="../../../../boost/numeric/conversion/cast.hpp">boost/numeric/conversion/cast.hpp</A></H1> </TH>
|
||||
</TR>
|
||||
</TABLE><HR>
|
||||
<H2>Contents</H2>
|
||||
<UL>
|
||||
<LI><A HREF="#introduction">Introduction</A></LI>
|
||||
<LI><A HREF="#numeric_cast"><CODE>numeric_cast</CODE></A></LI>
|
||||
<LI><A HREF="#examples">Examples</A></LI>
|
||||
</UL> <HR>
|
||||
<H2><A NAME="introduction">Introduction</A></H2>
|
||||
<P>The lack of preservation of range makes conversions between numeric
|
||||
types error prone. This is true for both implicit conversions and explicit
|
||||
conversions (through static_cast). <A HREF="#numeric_cast"> numeric_cast</A>
|
||||
detects loss of range when a numeric type is converted, and throws an
|
||||
exception if the range cannot be preserved.</P>
|
||||
<P>There are several situations where conversions are unsafe: </P>
|
||||
<UL>
|
||||
<LI>Conversions from an integral type with a wider range than the target
|
||||
integral type.</LI>
|
||||
<LI> Conversions from unsigned to signed (and vice versa) integral
|
||||
types.</LI>
|
||||
<LI> Conversions from floating point types to integral types.</LI>
|
||||
</UL>
|
||||
<P>The C++ Standard does not specify the behavior when a numeric type is
|
||||
assigned a value that cannot be represented by the type, except for unsigned
|
||||
integral types [3.9.1.4], which must obey the laws of arithmetic modulo
|
||||
2<SUP>n</SUP> (this implies that the result will be reduced modulo the number
|
||||
that is one greater than the largest value that can be represented). The fact
|
||||
that the behavior for overflow is undefined for all conversions (except the
|
||||
aforementioned unsigned to unsigned) makes any code that may produce positive
|
||||
or negative overflows exposed to portability issues.</P>
|
||||
<P>numeric_cast adheres to the rules for implicit conversions mandated by
|
||||
the C++ Standard, such as truncating floating point types when converting to
|
||||
integral types. The implementation must guarantee that for a conversion to a
|
||||
type that can hold all possible values of the source type, there will be no
|
||||
runtime overhead. <BR> <BR> </P> <HR>
|
||||
<H2><A NAME="numeric_cast"><CODE>numeric_cast</CODE></A></H2>
|
||||
<BLOCKQUOTE>
|
||||
<PRE>template<typename Target, typename Source> inline
|
||||
typename boost::numeric::converter<Target,Source>::result_type
|
||||
numeric_cast ( Source arg )
|
||||
{
|
||||
return boost::numeric::converter<Target,Source>::convert(arg);
|
||||
}
|
||||
</PRE> </BLOCKQUOTE>
|
||||
<P>numeric_cast returns the result of converting a value of type Source to a value of type
|
||||
Target. If out-of-range is detected, an exception is thrown (see
|
||||
<A HREF="converter_policies.html#bad_numc">bad_numeric_cast</A>, <A
|
||||
HREF="converter_policies.html#posovr">positive_overflow</A> and
|
||||
<A HREF="converter_policies.html#negovr">negative_overflow</A>). <BR> <BR> </P> <HR>
|
||||
<H2><A NAME="examples">Examples</A></H2>
|
||||
<P>The following example performs some typical conversions between numeric
|
||||
types: </P>
|
||||
<BLOCKQUOTE>
|
||||
<PRE>#include <boost/numeric/conversion/cast.hpp>
|
||||
#include <iostream>
|
||||
|
||||
int main()
|
||||
{
|
||||
using boost::numeric_cast;
|
||||
|
||||
using boost::numeric::bad_numeric_cast;
|
||||
using boost::numeric::positive_overflow;
|
||||
using boost::numeric::negative_overflow;
|
||||
|
||||
try
|
||||
{
|
||||
int i=42;
|
||||
short s=numeric_cast<short>(i); // This conversion succeeds (is in range)
|
||||
}
|
||||
catch(negative_overflow& e) {
|
||||
std::cout << e.what();
|
||||
}
|
||||
catch(positive_overflow& e) {
|
||||
std::cout << e.what();
|
||||
}
|
||||
|
||||
try
|
||||
{
|
||||
float f=-42.1234;
|
||||
|
||||
// This will cause a boost::numeric::negative_overflow exception to be thrown
|
||||
unsigned int i=numeric_cast<unsigned int>(f);
|
||||
}
|
||||
catch(bad_numeric_cast& e) {
|
||||
std::cout << e.what();
|
||||
}
|
||||
|
||||
double d= f + numeric_cast<double>(123); // int -> double
|
||||
|
||||
unsigned long l=std::numeric_limits<unsigned long>::max();
|
||||
|
||||
try
|
||||
{
|
||||
// This will cause a boost::numeric::positive_overflow exception to be thrown
|
||||
// NOTE: *operations* on unsigned integral types cannot cause overflow
|
||||
// but *conversions* to a signed type ARE range checked by numeric_cast.
|
||||
|
||||
unsigned char c=numeric_cast<unsigned char>(l);
|
||||
}
|
||||
catch(positive_overflow& e) {
|
||||
std::cout << e.what();
|
||||
}
|
||||
|
||||
|
||||
return 0;
|
||||
}</PRE> </BLOCKQUOTE> <BR> <BR> <HR>
|
||||
<HR>
|
||||
<P>Back to <A HREF="index.html">Numeric Conversion library index</A></P>
|
||||
<HR>
|
||||
<P>Revised 20 May 2006</P>
|
||||
<p>© Copyright Boost 1999</p>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 1999,2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
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</BODY>
|
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</HTML>
|
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@@ -1,116 +0,0 @@
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<HTML>
|
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<HEAD>
|
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<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
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||||
<LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css">
|
||||
<TITLE>Boost Numeric Conversion Library - Type Requirements and User-defined-types support</TITLE>
|
||||
</HEAD>
|
||||
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000ff" VLINK="#800080">
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<TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%"
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SUMMARY="header">
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<TR>
|
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<TH VALIGN="top" WIDTH="300">
|
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<H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277"
|
||||
ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH>
|
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<TH VALIGN="top">
|
||||
<H1 ALIGN="center">Boost Numeric Conversion Library</H1>
|
||||
<H1 ALIGN="center">Type Requirements<br>and<br>User-defined-types support</H1>
|
||||
</TH>
|
||||
</TR>
|
||||
</TABLE> <HR>
|
||||
<H2>Contents</H2>
|
||||
<DL CLASS="page-index">
|
||||
<DT><A HREF="#req">Type Requirements</A></DT>
|
||||
<DT><A HREF="#sem">UDT's special semantics</A></DT>
|
||||
<DT><A HREF="#hooks">Special Policies</A></DT>
|
||||
</DL>
|
||||
|
||||
|
||||
<HR>
|
||||
|
||||
<H2><A NAME="req"></A>Type Requirements</H2>
|
||||
<P>Both arithmetic (built-in) and user-defined numeric types require proper specialization of
|
||||
<CODE>std::numeric_limits<></CODE> (that is, with (in-class) integral constants).<br>
|
||||
The library uses <CODE>std::numeric_limits<T>::is_specialized</CODE> to detect whether
|
||||
the type is builtin or user defined, and <CODE>std::numeric_limits<T>::is_integer,
|
||||
std::numeric_limits<T>::is_signed</CODE>
|
||||
to detect whether the type is integer or floating point; and whether it is signed/unsigned.</P>
|
||||
<P>The default Float2IntRounder policies uses unqualified calls to functions <CODE>floor()
|
||||
and ceil()</CODE>; but the standard functions are introduced in scope by a
|
||||
using directive:</P>
|
||||
<PRE>using std::floor ; return floor(s); </PRE>
|
||||
<P>Therefore, for builtin arithmetic types, the std functions will be used.
|
||||
User defined types should provide overloaded versions of these functions in
|
||||
order to use the default rounder policies. If these overloads are defined within a user namespace
|
||||
argument dependent lookup (ADL) should find them, but if your compiler has a weak ADL
|
||||
you might need to put these functions some place else or write your own rounder policy.</P>
|
||||
<P>The default Trunc<> rounder policy needs to determine if the source value
|
||||
is positive or not, and for this it evaluates the expression "s < static_cast<S>(0)".
|
||||
Therefore, user defined types require a visible operator < in order to use
|
||||
the Trunc<> policy (the default).<br>
|
||||
</P>
|
||||
|
||||
<HR>
|
||||
<H2><A NAME="sem"></A>UDT's special semantics</H2>
|
||||
|
||||
<p><u>Conversion Traits</u></p>
|
||||
<p>If a User Defined Type is involved in a conversion, it is <i>assumed</i> that
|
||||
the UDT has <a href="definitions.html#range">wider range</a> than any built-in
|
||||
type, and consequently the values of some <code>converter_traits<></code>
|
||||
members are hardwired regardless of the reality. The following table summarizes
|
||||
this:</p>
|
||||
|
||||
<li>Target=UDT and Source=built-in
|
||||
<blockquote><code>subranged=false</code><br>
|
||||
<code>supertype=Target</code><br>
|
||||
<code>subtype=Source</code></blockquote>
|
||||
</li>
|
||||
|
||||
<li>Target=built-in and Source=UDT
|
||||
<blockquote><code>subranged=true</code><br>
|
||||
<code>supertype=Source</code><br>
|
||||
<code>subtype=Target</code></blockquote>
|
||||
</li>
|
||||
|
||||
<li>Target=UDT and Source=UDT
|
||||
<blockquote><code>subranged=false</code><br>
|
||||
<code>supertype=Target</code><br>
|
||||
<code>subtype=Source</code></blockquote>
|
||||
</li>
|
||||
<p>The Traits member <code>udt_mixture</code> can be used to detect whether a
|
||||
UDT is involved and to infer the validity of the other members as shown above.</p>
|
||||
<p><u>Range Checking</u></p>
|
||||
<p>Because User Defined Numeric Types might have peculiar ranges (such as an unbounded
|
||||
range), this library does not attempt to supply a meaningful range checking
|
||||
logic when UDTs are involved in a conversion. Therefore, if either Target or
|
||||
Source are not built-in types, the bundled range checking of the <code>converter<></code>
|
||||
function object is automatically disabled. However, it is possible to supply
|
||||
a user-defined range-checker. See <A HREF="#hooks">Special Policies</A></p>
|
||||
|
||||
<HR>
|
||||
<H2><A NAME="hooks"></A>Special Policies</H2>
|
||||
<p>There are two components of the <code>converter<></code> class that might
|
||||
require special behavior if User Defined Numeric Types are involved: the Range
|
||||
Checking and the Raw Conversion.</p>
|
||||
<p>When both Target and Source are built-in types, the converter class uses an
|
||||
<i>internal</i> range checking logic which is optimized and customized for the
|
||||
combined properties of the types.<br>
|
||||
However, this internal logic is disabled when either type is User Defined. In
|
||||
this case, the user can specify an <i>external</i> range checking policy which
|
||||
will be used in place of the internal code.
|
||||
See <a HREF="converter_policies.html#rc">UserRangeChecker</a> policy for details.</p>
|
||||
<p>The converter class performs the actual conversion using a Raw Converter policy.
|
||||
The default raw converter simply performs a <code>"static_cast<Target>(source)".</code><br>
|
||||
However, if the a UDT is involved, the static_cast might not work. In this case,
|
||||
the user can implement and pass a different raw converter policy.
|
||||
See <a HREF="converter_policies.html#rawc">RawConverter</a> policy for details </p>
|
||||
<HR>
|
||||
<P>Back to <A HREF="index.html">Numeric Conversion library index</A></P>
|
||||
<HR>
|
||||
<P>Revised 23 June 2004</P>
|
||||
<p>© Copyright Fernando Luis Cacciola Carballal, 2004</p>
|
||||
<p> Use, modification, and distribution are subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</BODY>
|
||||
</HTML>
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
Executable → Regular
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
+5
-5
@@ -1,13 +1,13 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="refresh" content="0; URL=doc/index.html">
|
||||
<meta http-equiv="refresh" content="0; URL=doc/html/index.html">
|
||||
</head>
|
||||
<body>
|
||||
Automatic redirection failed, please go to
|
||||
<a href="doc/index.html">doc/index.html</a>. <hr>
|
||||
<p>© Copyright Beman Dawes, 2001</p>
|
||||
<a href="doc/html/index.html">doc/index.html</a>. <hr>
|
||||
<p>� Copyright Beman Dawes, 2001</p>
|
||||
<p>Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file <a href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or copy
|
||||
file <a href="../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or copy
|
||||
at <a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</body>
|
||||
</html>
|
||||
</html>
|
||||
|
||||
@@ -1,4 +1,10 @@
|
||||
# Boost Numeric Conversion Library test Jamfile
|
||||
#
|
||||
# Copyright (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
#
|
||||
# Distributed under the Boost Software License, Version 1.0. (See
|
||||
# accompanying file LICENSE_1_0.txt or copy at
|
||||
# http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
test-suite numeric/conversion :
|
||||
[ run bounds_test.cpp ]
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// © Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
|
||||
// Use, modification, and distribution is subject to the Boost Software
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
// Copyright (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0. (See
|
||||
// accompanying file LICENSE_1_0.txt or copy at
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
// Copyright (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0. (See
|
||||
// accompanying file LICENSE_1_0.txt or copy at
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
// Copyright (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0. (See
|
||||
// accompanying file LICENSE_1_0.txt or copy at
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
// Copyright (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0. (See
|
||||
// accompanying file LICENSE_1_0.txt or copy at
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// (C) 2005, Fernando Luis Cacciola Carballal.
|
||||
// Copyright (C) 2005, Fernando Luis Cacciola Carballal.
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0. (See
|
||||
// accompanying file LICENSE_1_0.txt or copy at
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
// (C) 2003, Fernando Luis Cacciola Carballal.
|
||||
// (C) Copyright 2003, Fernando Luis Cacciola Carballal.
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0. (See
|
||||
// accompanying file LICENSE_1_0.txt or copy at
|
||||
|
||||
Reference in New Issue
Block a user