safe_numerics/doc/boostbook/safe_unsigned_range.xml

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<!DOCTYPE section PUBLIC "-//Boost//DTD BoostBook XML V1.1//EN"
"http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
<section id="safe_numerics.safe_unsigned_range">
  <title>safe_unsigned_range&lt;MIN, MAX, PP, EP&gt;</title>

  <section>
    <title>Description</title>

    <para>This type holds an unsigned integer in the closed range [MIN, MAX].
    A <code>safe_unsigned_range&lt;MIN, MAX, PP, EP&gt;</code> can be used
    anywhere an arithmetic type is permitted. Any expression which uses this
    type is guarenteed to return an arithmetically correct value or trap in
    some way.</para>
  </section>

  <section>
    <title>Notation</title>

    <informaltable>
      <tgroup cols="2">
        <colspec align="left" colwidth="2*"/>

        <colspec align="left" colwidth="10*"/>

        <thead>
          <row>
            <entry align="left">Symbol</entry>

            <entry align="left">Description</entry>
          </row>
        </thead>

        <tbody>
          <row>
            <entry><code>MIN, MAX</code></entry>

            <entry>Minimum and maximum unsigned values that the
            safe_unsigned_range can represent.</entry>
          </row>
        </tbody>
      </tgroup>
    </informaltable>
  </section>

  <section>
    <title>Associated Types</title>

    <informaltable>
      <tgroup cols="2">
        <colspec align="left" colwidth="2*"/>

        <colspec align="left" colwidth="10*"/>

        <tbody>
          <row>
            <entry><code>PP</code></entry>

            <entry>A type which specifes the result type of an expression
            using safe types.</entry>
          </row>

          <row>
            <entry><code>EP</code></entry>

            <entry>A type containing members which are called when a correct
            result cannot be returned</entry>
          </row>
        </tbody>
      </tgroup>
    </informaltable>
  </section>

  <section>
    <title>Template Parameters</title>

    <informaltable>
      <tgroup cols="3">
        <colspec align="left" colwidth="2*"/>

        <colspec align="left" colwidth="4*"/>

        <colspec align="left" colwidth="6*"/>

        <thead>
          <row>
            <entry align="left">Parameter</entry>

            <entry align="left">Requirements</entry>

            <entry>Description</entry>
          </row>
        </thead>

        <tbody>
          <row>
            <entry><code>MIN</code></entry>

            <entry>must be non-integer literal</entry>

            <entry>The minimum non-negative integer value that this type may
            hold</entry>
          </row>

          <row>
            <entry><code>MAX</code></entry>

            <entry>must be a non-negative literal</entry>

            <entry>The maximum non-negative integer value that this type may
            hold</entry>
          </row>

          <row>
            <entry/>

            <entry>MIN &lt;= MAX</entry>

            <entry>must be a valid closed range</entry>
          </row>

          <row>
            <entry><code>PP</code></entry>

            <entry><link linkend="safe_numerics.numeric"><link
            linkend="safe_numerics.promotion_policy">PromotionPolicy&lt;PP&gt;</link></link></entry>

            <entry><para>Default value is <link
            linkend="safe_numerics.promotion_policy.models.native">boost::numeric::native</link></para></entry>
          </row>

          <row>
            <entry><code>EP</code></entry>

            <entry><link linkend="safe_numerics.numeric"><link
            linkend="safe_numerics.exception_policy">Exception
            Policy&lt;EP&gt;</link></link></entry>

            <entry><para>Default value is <link
            linkend="safe_numerics.exception_policy.models.thow_exception">boost::throw_exception</link></para></entry>
          </row>
        </tbody>
      </tgroup>
    </informaltable>
  </section>

  <section>
    <title>Model of</title>

    <para><link linkend="safe_numerics.numeric">Integer</link></para>

    <para><link
    linkend="safe_numerics.safe_numeric_concept">SafeNumeric</link></para>
  </section>

  <section>
    <title>Valid Expressions</title>

    <para>Implements all expressions and only those expressions defined by the
    <link linkend="safe_numerics.safe_numeric_concept">SafeNumeric</link> type
    requirements. This, the result type of such an expression will be another
    safe type. The actual type of the result of such an expression will depend
    upon the specific promotion policy template parameter.</para>
  </section>

  <section>
    <title>Header</title>

    <para><filename><ulink url="../../include/safe_range.hpp">#include
    &lt;safe/numeric/safe_range.hpp&gt;</ulink></filename></para>
  </section>

  <section>
    <title>Example of use</title>

    <programlisting>#include &lt;safe/numeric/safe_range.hpp&gt;

void f(){
    boost::numeric::safe_unsigned_range&lt;7, 24&gt; i;
    // since the range is included in [0,255], the underlying type of i 
    // will be an unsigned char.
    i = 0;  // throws out_of_range exception
    i = 9;  // ok
    i *= 9; // throws out_of_range exception
    i = -1; // throws out_of_range exception
    std::uint8_t j = 4;
    auto k = i + j;
        // These types use default promotion policy so standard C++ type promotion rules 
        // will be used in evaluating expressions.   C++ type promotion rules mandate
        // that the result of k = i + j when both are unsigned char types, will be another
        // unsigned char type.
  }</programlisting>
  </section>
</section>