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Added MPL-compatible variants of the minimum-size and value-based integer templates, which fixes #1224

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[SVN r47470]
This commit is contained in:
Daryle Walker
2008-07-16 09:55:31 +00:00
parent f27ad7b337
commit ed80575830
4 changed files with 416 additions and 76 deletions
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125
integer.htm
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@ -53,6 +53,16 @@ namespace boost
};
// MPL-compatible
template< int Bits, typename Signedness >
struct sized_integral
{
static bool const is_specialized = <em>implementation_supplied</em>;
static bool const is_signed = <em>implementation_supplied</em>;
static int const bit_count = Bits;
typedef <em>implementation_supplied</em> type;
};
template&lt; int Bits, typename Signedness &gt;
struct exact_integral
{
@ -63,12 +73,42 @@ namespace boost
typedef <em>implementation_supplied</em> type;
};
template&lt; intmax_t MaxValue &gt;
struct maximum_signed_integral
{
static bool const is_specialized = <em>implementation_supplied</em>;
static bool const is_signed = true;
static intmax_t const bound = MaxValue;
typedef <em>implementation_supplied</em> type;
};
template&lt; intmax_t MinValue &gt;
struct minimum_signed_integral
{
static bool const is_specialized = <em>implementation_supplied</em>;
static bool const is_signed = true;
static intmax_t const bound = MinValue;
typedef <em>implementation_supplied</em> type;
};
template&lt; uintmax_t Value &gt;
struct maximum_unsigned_integral
{
static bool const is_specialized = <em>implementation_supplied</em>;
static bool const is_signed = false;
static uintmax_t const bound = Value;
typedef <em>implementation_supplied</em> type;
};
// signed
template&lt; int Bits &gt;
struct int_t
{
typedef <em>implementation_supplied</em> least;
typedef int_fast_t&lt;least&gt;::fast fast;
typedef typename sized_integral&lt;Bits, signed&gt;::type least;
typedef int_fast_t&lt;least&gt;::fast fast;
};
template&lt; int Bits &gt;
@ -81,8 +121,8 @@ namespace boost
template&lt; int Bits &gt;
struct uint_t
{
typedef <em>implementation_supplied</em> least;
typedef int_fast_t&lt;least&gt;::fast fast;
typedef typename sized_integral&lt;Bits, unsigned&gt;::type least;
typedef int_fast_t&lt;least&gt;::fast fast;
};
template&lt; int Bits &gt;
@ -95,23 +135,23 @@ namespace boost
template&lt; intmax_t MaxValue &gt;
struct int_max_value_t
{
typedef <em>implementation_supplied</em> least;
typedef int_fast_t&lt;least&gt;::fast fast;
typedef typename maximum_signed_integral&lt;MaxValue&gt;::type least;
typedef int_fast_t&lt;least&gt;::fast fast;
};
template&lt; intmax_t MinValue &gt;
struct int_min_value_t
{
typedef <em>implementation_supplied</em> least;
typedef int_fast_t&lt;least&gt;::fast fast;
typedef typename minimum_signed_integral&lt;MinValue&gt;::type least;
typedef int_fast_t&lt;least&gt;::fast fast;
};
// unsigned
template&lt; uintmax_t Value &gt;
struct uint_value_t
{
typedef <em>implementation_supplied</em> least;
typedef int_fast_t&lt;least&gt;::fast fast;
typedef typename maximum_unsigned_integral&lt;Value&gt;::type least;
typedef int_fast_t&lt;least&gt;::fast fast;
};
} // namespace boost
</pre></blockquote>
@ -222,8 +262,10 @@ describes each template's criteria.</p>
incompatible with template meta-programming techniques.</li>
</ul>
<p>The <code>exact_integral</code> class template provides an MPL-compatible
alternative. This alternative has the form:</p>
<p>The <code>sized_integral</code>, <code>exact_integral</code>,
<code>maximum_signed_integral</code>, <code>minimum_signed_integral</code>, and
<code>maximum_unsigned_integral</code> class templates provide MPL-compatible
alternatives. These alternatives generally have the form:</p>
<blockquote><pre>
template&lt; <var>SwitchType</var> <var>SwitchValue</var>, typename Signedness &gt;
@ -299,6 +341,11 @@ struct <var>name</var>
</tr>
</table>
<p>The exceptions are the extreme-value class templates
(<code>maximum_signed_integral</code>, <code>minimum_signed_integral</code>, and
<code>maximum_unsigned_integral</code>), which do not take a <var>Signedness</var>
template parameter because the meta-functions already inherently have signedness.
<p>The following table describes each template's criteria. The classic signed
and unsigned equivalents are the sized-type class templates that each
MPL-compatible class template emulates. (The setting of <var>Signedness</var>
@ -308,24 +355,66 @@ controls the appropriate emulation.)</p>
<caption>Criteria for the MPL-Compatible Class Templates</caption>
<tr>
<th rowspan="2">Class Template (all in name-space <code>boost</code>)</th>
<th rowspan="2">Parameter Type</th>
<th rowspan="2">Parameter Type (in name-space <code>boost</code> as needed)</th>
<th rowspan="2">Parameter Member ID</th>
<th colspan="2">Classic Equivalent</th>
<th rowspan="2">Template Parameter Mapping (when <code>type</code> is defined)</th>
<th rowspan="2" colspan="2">Template Parameter Mapping (when <code>type</code> is defined)</th>
</tr>
<tr>
<th>Signed</th>
<th>Unsigned</th>
</tr>
<tr>
<td><code>sized_integral</code></td>
<td><code>int</code></td>
<td><code>bit_count</code></td>
<td><code>int_t</code></td>
<td><code>uint_t</code></td>
<td colspan="2">The smallest built-in integral type with at least
<code>bit_count</code> bits (including the sign bit when
<var>Signedness</var> is <code>signed</code>). Not present if no
type qualifies.</td>
</tr>
<tr>
<td><code>exact_integral</code></td>
<td><code>int</code></td>
<td><code>bit_count</code></td>
<td><code>int_exact_t</code></td>
<td><code>uint_exact_t</code></td>
<td>The smallest built-in integral type with exactly <code>bit_count</code>
bits (including the sign bit when <var>Signedness</var> is
<code>signed</code>). Not present if no type qualifies.</td>
<td colspan="2">The smallest built-in integral type with exactly
<code>bit_count</code> bits (including the sign bit when
<var>Signedness</var> is <code>signed</code>). Not present if no
type qualifies.</td>
</tr>
<tr>
<td><code>maximum_signed_integral</code></td>
<td><code>intmax_t</code></td>
<td><code>bound</code></td>
<td colspan="2"><code>int_max_value_t</code></td>
<td>The smallest built-in integral type that can perserve the value in
<code>bound</code>. Not present if <code>bound</code> is non-positive.</td>
<td rowspan="3">It is possible for a <code>type</code> to be absent if
a platform supports really-extended integral types (beyond <code>long
long</code> or <code>__int64</code>), support for those types goes
into &lt;<a href="../../boost/cstdint.hpp">boost/cstdint.hpp</a>&gt;,
but said support hadn't yet been added to &lt;<a
href="../../boost/integer.hpp">boost/integer.hpp</a>&gt;</td>
</tr>
<tr>
<td><code>minimum_signed_integral</code></td>
<td><code>intmax_t</code></td>
<td><code>bound</code></td>
<td colspan="2"><code>int_min_value_t</code></td>
<td>The smallest built-in integral type that can perserve the value in
<code>bound</code>. Not present if <code>bound</code> is non-negative.</td>
</tr>
<tr>
<td><code>maximum_unsigned_integral</code></td>
<td><code>uintmax_t</code></td>
<td><code>bound</code></td>
<td colspan="2"><code>uint_value_t</code></td>
<td>The smallest built-in integral type that can perserve the value in
<code>bound</code>. Should always be present.</td>
</tr>
</table>
@ -406,7 +495,7 @@ exact and value-based sized templates, and the MPL-compatible templates.</p>
<hr>
<p>Revised July 15, 2008</p>
<p>Revised July 16, 2008</p>
<p>&copy; Copyright Beman Dawes 1999. Use, modification, and distribution are
subject to the Boost Software License, Version 1.0. (See accompanying file <a