| 1 | <HTML> |
|---|
| 2 | <HEAD> |
|---|
| 3 | <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> |
|---|
| 4 | <LINK REL="stylesheet" TYPE="text/css" HREF="../../../../boost.css"> |
|---|
| 5 | <TITLE>Boost Numeric Conversion Library - Index</TITLE> |
|---|
| 6 | </HEAD> |
|---|
| 7 | <BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000ff" VLINK="#800080"> |
|---|
| 8 | <TABLE BORDER="0" CELLPADDING="7" CELLSPACING="0" WIDTH="100%" |
|---|
| 9 | SUMMARY="header"> |
|---|
| 10 | <TR> |
|---|
| 11 | <TH VALIGN="top" WIDTH="300"> |
|---|
| 12 | <H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277" |
|---|
| 13 | ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH> |
|---|
| 14 | <TH VALIGN="top"> |
|---|
| 15 | <H1 ALIGN="center">Boost Numeric Conversion Library</H1> </TH> |
|---|
| 16 | </TR> |
|---|
| 17 | </TABLE> |
|---|
| 18 | <HR> |
|---|
| 19 | <table border="0" cellpadding="0" width="100%"> |
|---|
| 20 | <tr> |
|---|
| 21 | <td width="50%" valign="top"><font size="4">This Document</font><br><br> |
|---|
| 22 | <a href="#Overview">Overview</a><br> |
|---|
| 23 | <a href="#Ack">History and Acknowledgments</a><br> |
|---|
| 24 | <a href="#Ref">Bibliography</a><br> |
|---|
| 25 | </td> |
|---|
| 26 | <td width="50%"><font size="4">Other Documents</font><br><br> |
|---|
| 27 | <A HREF="definitions.html">Definitions</A><br> |
|---|
| 28 | <A HREF="converter.html"><code>converter<></code> function object</A><br> |
|---|
| 29 | <A HREF="requirements.html">Type Requirements and User-defined-types support</A><br> |
|---|
| 30 | <A HREF="bounds.html"><code>bounds<></code> traits class</A><br> |
|---|
| 31 | <A HREF="conversion_traits.html"><code>conversion_traits<></code> traits class</A><br> |
|---|
| 32 | <A HREF="converter_policies.html">Numeric Converter Policy Classes</A><br> |
|---|
| 33 | <A HREF="numeric_cast.html">Improved numeric_cast<></A><br> |
|---|
| 34 | </td> |
|---|
| 35 | </tr> |
|---|
| 36 | </table> |
|---|
| 37 | |
|---|
| 38 | <hr> |
|---|
| 39 | <H2><A NAME="Overview"></A>Overview</H2> |
|---|
| 40 | <P>The Boost Numeric Conversion library is a collection of tools to describe and perform |
|---|
| 41 | conversions between values of different <a href="definitions.html#numtypes">numeric types</a>.</p> |
|---|
| 42 | <p>The library includes a special alternative for a subset of <code>std::numeric_limits<></code>, |
|---|
| 43 | the <A HREF="bounds.html"><code>bounds<></code></A> traits class, which provides |
|---|
| 44 | a consistent way to obtain the <a href="definitions.html#range">boundary</a> values for the |
|---|
| 45 | <a href="definitions.html#range">range</a> of a numeric type.</p> |
|---|
| 46 | <p>It also includes a set of <A HREF="conversion_traits.html">trait classes</A> which |
|---|
| 47 | describes the compile-time properties of a conversion from a source to a target |
|---|
| 48 | numeric type. Both <a href="definitions.html#stdtypes">arithmetic</a> and <a href="definitions.html#numtypes">user-defined |
|---|
| 49 | numeric types</a> can be used.</p> |
|---|
| 50 | <p>A policy-based <A HREF="converter.html">converter</A> object which uses <code>conversion_traits</code> |
|---|
| 51 | to select an optimized implementation is supplied. |
|---|
| 52 | Such implementation uses an optimal range checking code suitable for the source/target combination.<br> |
|---|
| 53 | The converter's out-of-range behavior can be customized via an <A HREF="converter_policies.html#oh">OverflowHandler</A> |
|---|
| 54 | policy.<br> |
|---|
| 55 | For floating-point to integral conversions, the rounding mode can be selected via |
|---|
| 56 | the <A HREF="converter_policies.html#f2i">Float2IntRounder</A> policy.<br> |
|---|
| 57 | A custom low-level conversion routine (for UDTs for instance) can be passed |
|---|
| 58 | via a <A HREF="converter_policies.html#rawc">RawConverter</A> policy.<br> |
|---|
| 59 | The optimized automatic range-checking logic can be overridden via a <A HREF="converter_policies.html#rc">UserRangeChecker</A> |
|---|
| 60 | policy.</p> |
|---|
| 61 | <hr> |
|---|
| 62 | <H2><A NAME="Ack"></A>History and Acknowledgments</H2> |
|---|
| 63 | <p>Pre-formal review:</p> |
|---|
| 64 | <blockquote> |
|---|
| 65 | <p>Kevlin Henney, with help from David Abrahams and Beman Dawes, originally contributed |
|---|
| 66 | the previous version of numeric_cast<> which already presented the idea of a runtime range check.<br> |
|---|
| 67 | Later, Eric Ford, Kevin Lynch and the author spotted some genericity problems |
|---|
| 68 | with that numeric_cast<> which prevented it from being used in a generic |
|---|
| 69 | layer of math functions.<br> |
|---|
| 70 | An improved numeric_cast<> which properly handled all combinations of arithmetic types was presented.<br> |
|---|
| 71 | David Abrahams and Beman Dawes acknowledged the need of an improved version |
|---|
| 72 | of numeric_cast<> and supported the submission as originally laid out. |
|---|
| 73 | Daryl Walker and Darin Adler made some important comments and proposed fixes |
|---|
| 74 | to the original submission.</p> |
|---|
| 75 | <p>Special thanks go to Björn Karlsoon who helped the author considerably. Having |
|---|
| 76 | found the problems with numeric_cast<> himself, he revised very carefully |
|---|
| 77 | the original submission and spot a subtle bug in the range checking implementation. |
|---|
| 78 | He also wrote part of this documentation and proof-read and corrected other |
|---|
| 79 | parts. And most importantly: the features now presented here in this library |
|---|
| 80 | evolved from the original submission as a result of the useful private communications |
|---|
| 81 | between Björn and the author.</p> |
|---|
| 82 | </blockquote> |
|---|
| 83 | <p>Post-formal review:</p> |
|---|
| 84 | <p>Guillaume Melquiond spoted some documentation and code issues, particularly about rounding conversions.<br> |
|---|
| 85 | The following people contributed an important review of the design, documentation and code: Kevin Lynch, Thorsten Ottosen, Paul Bristow, |
|---|
| 86 | Daryle Walker, Jhon Torjo, Eric Ford, Gennadiy Rozental. |
|---|
| 87 | </p> |
|---|
| 88 | <hr> |
|---|
| 89 | <H2><A NAME="Ref"></A>Bibliography</H2> |
|---|
| 90 | <ul> |
|---|
| 91 | <li>Standard Documents: |
|---|
| 92 | <ol> |
|---|
| 93 | <li>ISO/IEC 14882:98 (C++98 Standard)</li> |
|---|
| 94 | <li>ISO/IEC 9899:1999 (C99 Standard)</li> |
|---|
| 95 | <li>ISO/IEC 10967-1 (Language Independent Arithmetic (LIA), Part I, 1994)</li> |
|---|
| 96 | <li>ISO/IEC 2382-1:1993 (Information Technology - Vocabulary - Part I: Fundamental Terms)</li> |
|---|
| 97 | <li>ANSI/IEEE 754-1985 [and IEC 60559:1989] (Binary floating-point)</li> |
|---|
| 98 | <li>ANSI/IEEE 854-1988 (Radix Independent floating-point)</li> |
|---|
| 99 | <li>ANSI X3/TR-1-82 (Dictionary for Information Processing Systems)</li> |
|---|
| 100 | <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> |
|---|
| 101 | </ol> |
|---|
| 102 | </li> |
|---|
| 103 | <li>Papers: |
|---|
| 104 | <ol> |
|---|
| 105 | <li>David Goldberg <A href="http://citeseer.ist.psu.edu/goldberg91what.html"> |
|---|
| 106 | What Every Computer Scientist Should Know About Floating-Point Arithmetic</A></li> |
|---|
| 107 | <li><A href="http://www.cs.berkeley.edu/~wkahan/">Prof. William Kahan</A> papers on floating-point.</li> |
|---|
| 108 | </ol> |
|---|
| 109 | </li> |
|---|
| 110 | </ul> |
|---|
| 111 | <HR> |
|---|
| 112 | <P>Revised 23 June 2004</P> |
|---|
| 113 | <p>© Copyright Fernando Luis Cacciola Carballal, 2004</p> |
|---|
| 114 | <p> Use, modification, and distribution are subject to the Boost Software |
|---|
| 115 | License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt"> |
|---|
| 116 | LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt"> |
|---|
| 117 | www.boost.org/LICENSE_1_0.txt</a>)</p> |
|---|
| 118 | </body> |
|---|
| 119 | </HTML> |
|---|
