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type_requirements_and_user_defined_types_support.html

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  27. <a name="boost_numericconversion.type_requirements_and_user_defined_types_support"></a><a class="link" href="type_requirements_and_user_defined_types_support.html" title="Type Requirements and User-defined-types support">Type
    28. 

  28.     Requirements and User-defined-types support</a>
    29. 

  29. </h2></div></div></div>
    30. 

  30. <div class="toc"><dl class="toc">
    31. 

  31. <dt><span class="section"><a href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.type_requirements">Type
    32. 

  32.       Requirements</a></span></dt>
    33. 

  33. <dt><span class="section"><a href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics">UDT's
    34. 

  34.       special semantics</a></span></dt>
    35. 

  35. <dt><span class="section"><a href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.special_policies">Special
    36. 

  36.       Policies</a></span></dt>
    37. 

  37. <dt><span class="section"><a href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.udts_with_numeric_cast">UDTs
    38. 

  38.       with numeric_cast</a></span></dt>
    39. 

  39. </dl></div>
    40. 

  40. <div class="section">
    41. 

  41. <div class="titlepage"><div><div><h3 class="title">
    42. 

  42. <a name="boost_numericconversion.type_requirements_and_user_defined_types_support.type_requirements"></a><a class="link" href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.type_requirements" title="Type Requirements">Type
    43. 

  43.       Requirements</a>
    44. 

  44. </h3></div></div></div>
    45. 

  45. <p>
    46. 

  46.         Both arithmetic (built-in) and user-defined numeric types require proper
    47. 

  47.         specialization of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;&gt;</span></code>
    48. 

  48.         (that is, with (in-class) integral constants).
    49. 

  49.       </p>
    50. 

  50. <p>
    51. 

  51.         The library uses <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">is_specialized</span></code> to detect whether the type
    52. 

  52.         is builtin or user defined, and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">is_integer</span></code>, <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">is_signed</span></code> to detect whether the type is
    53. 

  53.         integer or floating point; and whether it is signed/unsigned.
    54. 

  54.       </p>
    55. 

  55. <p>
    56. 

  56.         The default <code class="computeroutput"><span class="identifier">Float2IntRounder</span></code>
    57. 

  57.         policies uses unqualified calls to functions <code class="computeroutput"><span class="identifier">floor</span><span class="special">()</span></code> and <code class="computeroutput"><span class="identifier">ceil</span><span class="special">()</span></code>; but the standard functions are introduced
    58. 

  58.         in scope by a using directive:
    59. 

  59.       </p>
    60. 

  60. <pre class="programlisting"><span class="keyword">using</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">floor</span> <span class="special">;</span> <span class="keyword">return</span> <span class="identifier">floor</span><span class="special">(</span><span class="identifier">s</span><span class="special">);</span>
    61. 

  61. </pre>
    62. 

  62. <p>
    63. 

  63.         Therefore, for builtin arithmetic types, the std functions will be used.
    64. 

  64.         User defined types should provide overloaded versions of these functions
    65. 

  65.         in order to use the default rounder policies. If these overloads are defined
    66. 

  66.         within a user namespace argument dependent lookup (ADL) should find them,
    67. 

  67.         but if your compiler has a weak ADL you might need to put these functions
    68. 

  68.         some place else or write your own rounder policy.
    69. 

  69.       </p>
    70. 

  70. <p>
    71. 

  71.         The default <code class="computeroutput"><span class="identifier">Trunc</span><span class="special">&lt;&gt;</span></code>
    72. 

  72.         rounder policy needs to determine if the source value is positive or not,
    73. 

  73.         and for this it evaluates the expression <code class="computeroutput"><span class="identifier">s</span>
    74. 

  74.         <span class="special">&lt;</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;(</span><span class="number">0</span><span class="special">)</span></code>. Therefore,
    75. 

  75.         user defined types require a visible <code class="computeroutput"><span class="keyword">operator</span><span class="special">&lt;</span></code> in order to use the <code class="computeroutput"><span class="identifier">Trunc</span><span class="special">&lt;&gt;</span></code> policy (the default).
    76. 

  76.       </p>
    77. 

  77. </div>
    78. 

  78. <div class="section">
    79. 

  79. <div class="titlepage"><div><div><h3 class="title">
    80. 

  80. <a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics"></a><a class="link" href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics" title="UDT's special semantics">UDT's
    81. 

  81.       special semantics</a>
    82. 

  82. </h3></div></div></div>
    83. 

  83. <h5>
    84. 

  84. <a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.h0"></a>
    85. 

  85.         <span class="phrase"><a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.conversion_traits"></a></span><a class="link" 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
    86. 

  86.         Traits</a>
    87. 

  87.       </h5>
    88. 

  88. <p>
    89. 

  89.         If a User Defined Type is involved in a conversion, it is <span class="emphasis"><em>assumed</em></span>
    90. 

  90.         that the UDT has <a class="link" href="definitions.html#boost_numericconversion.definitions.range_and_precision" title="Range and Precision">wider
    91. 

  91.         range</a> than any built-in type, and consequently the values of some
    92. 

  92.         <code class="computeroutput"><span class="identifier">converter_traits</span><span class="special">&lt;&gt;</span></code>
    93. 

  93.         members are hardwired regardless of the reality. The following table summarizes
    94. 

  94.         this:
    95. 

  95.       </p>
    96. 

  96. <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
    97. 

  97. <li class="listitem">
    98. 

  98.             <code class="computeroutput"><span class="identifier">Target</span><span class="special">=</span></code><span class="emphasis"><em>UDT</em></span>
    99. 

  99.             and <code class="computeroutput"><span class="identifier">Source</span><span class="special">=</span></code><span class="emphasis"><em>built-in</em></span>
    100. 

  100.             <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; ">
    101. 

  101. <li class="listitem">
    102. 

  102.                   <code class="computeroutput"><span class="identifier">subranged</span><span class="special">=</span><span class="keyword">false</span></code>
    103. 

  103.                 </li>
    104. 

  104. <li class="listitem">
    105. 

  105.                   <code class="computeroutput"><span class="identifier">supertype</span><span class="special">=</span><span class="identifier">Target</span></code>
    106. 

  106.                 </li>
    107. 

  107. <li class="listitem">
    108. 

  108.                   <code class="computeroutput"><span class="identifier">subtype</span><span class="special">=</span><span class="identifier">Source</span></code>
    109. 

  109.                 </li>
    110. 

  110. </ul></div>
    111. 

  111.           </li>
    112. 

  112. <li class="listitem">
    113. 

  113.             <code class="computeroutput"><span class="identifier">Target</span><span class="special">=</span></code><span class="emphasis"><em>built-in</em></span>
    114. 

  114.             and <code class="computeroutput"><span class="identifier">Source</span><span class="special">=</span></code><span class="emphasis"><em>UDT</em></span>
    115. 

  115.             <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; ">
    116. 

  116. <li class="listitem">
    117. 

  117.                   <code class="computeroutput"><span class="identifier">subranged</span><span class="special">=</span><span class="keyword">true</span></code>
    118. 

  118.                 </li>
    119. 

  119. <li class="listitem">
    120. 

  120.                   <code class="computeroutput"><span class="identifier">supertype</span><span class="special">=</span><span class="identifier">Source</span></code>
    121. 

  121.                 </li>
    122. 

  122. <li class="listitem">
    123. 

  123.                   <code class="computeroutput"><span class="identifier">subtype</span><span class="special">=</span><span class="identifier">Target</span></code>
    124. 

  124.                 </li>
    125. 

  125. </ul></div>
    126. 

  126.           </li>
    127. 

  127. <li class="listitem">
    128. 

  128.             <code class="computeroutput"><span class="identifier">Target</span><span class="special">=</span></code><span class="emphasis"><em>UDT</em></span>
    129. 

  129.             and <code class="computeroutput"><span class="identifier">Source</span><span class="special">=</span></code><span class="emphasis"><em>UDT</em></span>
    130. 

  130.             <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; ">
    131. 

  131. <li class="listitem">
    132. 

  132.                   <code class="computeroutput"><span class="identifier">subranged</span><span class="special">=</span><span class="keyword">false</span></code>
    133. 

  133.                 </li>
    134. 

  134. <li class="listitem">
    135. 

  135.                   <code class="computeroutput"><span class="identifier">supertype</span><span class="special">=</span><span class="identifier">Target</span></code>
    136. 

  136.                 </li>
    137. 

  137. <li class="listitem">
    138. 

  138.                   <code class="computeroutput"><span class="identifier">subtype</span><span class="special">=</span><span class="identifier">Source</span></code>
    139. 

  139.                 </li>
    140. 

  140. </ul></div>
    141. 

  141.           </li>
    142. 

  142. </ul></div>
    143. 

  143. <p>
    144. 

  144.         The <code class="computeroutput"><span class="identifier">Traits</span></code> member <code class="computeroutput"><span class="identifier">udt_mixture</span></code> can be used to detect whether
    145. 

  145.         a UDT is involved and to infer the validity of the other members as shown
    146. 

  146.         above.
    147. 

  147.       </p>
    148. 

  148. <h5>
    149. 

  149. <a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.h1"></a>
    150. 

  150.         <span class="phrase"><a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udt_s_special_semantics.range_checking"></a></span><a class="link" 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
    151. 

  151.         Checking</a>
    152. 

  152.       </h5>
    153. 

  153. <p>
    154. 

  154.         Because User Defined Numeric Types might have peculiar ranges (such as an
    155. 

  155.         unbounded range), this library does not attempt to supply a meaningful range
    156. 

  156.         checking logic when UDTs are involved in a conversion. Therefore, if either
    157. 

  157.         Target or Source are not built-in types, the bundled range checking of the
    158. 

  158.         <code class="computeroutput"><span class="identifier">converter</span><span class="special">&lt;&gt;</span></code>
    159. 

  159.         function object is automatically disabled. However, it is possible to supply
    160. 

  160.         a user-defined range-checker. See <a class="link" href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.special_policies" title="Special Policies">Special
    161. 

  161.         Policies</a>
    162. 

  162.       </p>
    163. 

  163. </div>
    164. 

  164. <div class="section">
    165. 

  165. <div class="titlepage"><div><div><h3 class="title">
    166. 

  166. <a name="boost_numericconversion.type_requirements_and_user_defined_types_support.special_policies"></a><a class="link" href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.special_policies" title="Special Policies">Special
    167. 

  167.       Policies</a>
    168. 

  168. </h3></div></div></div>
    169. 

  169. <p>
    170. 

  170.         There are two components of the <code class="computeroutput"><span class="identifier">converter</span><span class="special">&lt;&gt;</span></code> class that might require special
    171. 

  171.         behavior if User Defined Numeric Types are involved: the Range Checking and
    172. 

  172.         the Raw Conversion.
    173. 

  173.       </p>
    174. 

  174. <p>
    175. 

  175.         When both Target and Source are built-in types, the converter class uses
    176. 

  176.         an internal range checking logic which is optimized and customized for the
    177. 

  177.         combined properties of the types.
    178. 

  178.       </p>
    179. 

  179. <p>
    180. 

  180.         However, this internal logic is disabled when either type is User Defined.
    181. 

  181.         In this case, the user can specify an <span class="emphasis"><em>external</em></span> range
    182. 

  182.         checking policy which will be used in place of the internal code. See <a class="link" href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.udts_with_numeric_cast" title="UDTs with numeric_cast">numeric_cast_traits</a>
    183. 

  183.         for details on using UDTs with <code class="computeroutput"><span class="identifier">numeric_cast</span></code>.
    184. 

  184.       </p>
    185. 

  185. <p>
    186. 

  186.         The converter class performs the actual conversion using a Raw Converter
    187. 

  187.         policy. The default raw converter simply performs a <code class="computeroutput"><span class="keyword">static_cast</span><span class="special">&lt;</span><span class="identifier">Target</span><span class="special">&gt;(</span><span class="identifier">source</span><span class="special">)</span></code>.
    188. 

  188.       </p>
    189. 

  189. <p>
    190. 

  190.         However, if the a UDT is involved, the <code class="computeroutput"><span class="keyword">static_cast</span></code>
    191. 

  191.         might not work. In this case, the user can implement and pass a different
    192. 

  192.         raw converter policy. See <a class="link" href="numeric_converter_policy_classes.html#boost_numericconversion.numeric_converter_policy_classes.policy_rawconverter" title="Policy RawConverter">RawConverter</a>
    193. 

  193.         policy for details.
    194. 

  194.       </p>
    195. 

  195. </div>
    196. 

  196. <div class="section">
    197. 

  197. <div class="titlepage"><div><div><h3 class="title">
    198. 

  198. <a name="boost_numericconversion.type_requirements_and_user_defined_types_support.udts_with_numeric_cast"></a><a class="link" href="type_requirements_and_user_defined_types_support.html#boost_numericconversion.type_requirements_and_user_defined_types_support.udts_with_numeric_cast" title="UDTs with numeric_cast">UDTs
    199. 

  199.       with numeric_cast</a>
    200. 

  200. </h3></div></div></div>
    201. 

  201. <p>
    202. 

  202.         In order to employ UDTs with <code class="computeroutput"><span class="identifier">numeric_cast</span></code>,
    203. 

  203.         the user should define a <code class="computeroutput"><span class="identifier">numeric_cast_traits</span></code>
    204. 

  204.         specialization on the UDT for each conversion. Here is an example of specializations
    205. 

  205.         for converting between the UDT and any other type:
    206. 

  206.       </p>
    207. 

  207. <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>
    208. 

  208. <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Source</span><span class="special">&gt;</span>
    209. 

  209. <span class="keyword">struct</span> <span class="identifier">numeric_cast_traits</span><span class="special">&lt;</span><span class="identifier">UDT</span><span class="special">,</span> <span class="identifier">Source</span><span class="special">&gt;</span>
    210. 

  210. <span class="special">{</span>
    211. 

  211.     <span class="keyword">typedef</span> <span class="identifier">conversion_traits</span><span class="special">&lt;</span><span class="identifier">UDT</span><span class="special">,</span> <span class="identifier">Source</span><span class="special">&gt;</span>      <span class="identifier">conv_traits</span><span class="special">;</span>
    212. 

  212. 

  213.     <span class="comment">//! The following are required:</span>
    214. 

  214.     <span class="keyword">typedef</span> <span class="identifier">YourOverflowHandlerPolicy</span>           <span class="identifier">overflow_policy</span><span class="special">;</span>
    215. 

  215.     <span class="keyword">typedef</span> <span class="identifier">YourRangeCheckerPolicy</span><span class="special">&lt;</span><span class="identifier">conv_traits</span><span class="special">&gt;</span> <span class="identifier">range_checking_policy</span><span class="special">;</span>
    216. 

  216.     <span class="keyword">typedef</span> <span class="identifier">YourFloat2IntRounderPolicy</span><span class="special">&lt;</span><span class="identifier">Source</span><span class="special">&gt;</span>  <span class="identifier">rounding_policy</span><span class="special">;</span>
    217. 

  217. <span class="special">};</span>
    218. 

  218. <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Target</span><span class="special">&gt;</span>
    219. 

  219. <span class="keyword">struct</span> <span class="identifier">numeric_cast_traits</span><span class="special">&lt;</span><span class="identifier">Target</span><span class="special">,</span> <span class="identifier">UDT</span><span class="special">&gt;</span>
    220. 

  220. <span class="special">{</span>
    221. 

  221.     <span class="keyword">typedef</span> <span class="identifier">conversion_traits</span><span class="special">&lt;</span><span class="identifier">Target</span><span class="special">,</span> <span class="identifier">UDT</span><span class="special">&gt;</span>      <span class="identifier">conv_traits</span><span class="special">;</span>
    222. 

  222. 

  223.     <span class="comment">//! The following are required:</span>
    224. 

  224.     <span class="keyword">typedef</span> <span class="identifier">YourOverflowHandlerPolicy</span>           <span class="identifier">overflow_policy</span><span class="special">;</span>
    225. 

  225.     <span class="keyword">typedef</span> <span class="identifier">YourRangeCheckerPolicy</span><span class="special">&lt;</span><span class="identifier">conv_traits</span><span class="special">&gt;</span> <span class="identifier">range_checking_policy</span><span class="special">;</span>
    226. 

  226.     <span class="keyword">typedef</span> <span class="identifier">YourFloat2IntRounderPolicy</span><span class="special">&lt;</span><span class="identifier">UDT</span><span class="special">&gt;</span>     <span class="identifier">rounding_policy</span><span class="special">;</span>
    227. 

  227. <span class="special">};</span>
    228. 

  228. <span class="special">}}//</span><span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">;</span>
    229. 

  229. </pre>
    230. 

  230. <p>
    231. 

  231.         These specializations are already defined with default values for the built-in
    232. 

  232.         numeric types. It is possible to disable the generation of specializations
    233. 

  233.         for built-in types by defining <code class="computeroutput"><span class="identifier">BOOST_NUMERIC_CONVERSION_RELAX_BUILT_IN_CAST_TRAITS</span></code>.
    234. 

  234.         For details on defining custom policies see <a class="link" href="numeric_converter_policy_classes.html" title="Numeric Converter Policy Classes">Converter
    235. 

  235.         Policies</a>.
    236. 

  236.       </p>
    237. 

  237. <p>
    238. 

  238.         Here is a full example of how to define a custom UDT for use with <code class="computeroutput"><span class="identifier">numeric_cast</span></code>:
    239. 

  239.       </p>
    240. 

  240. <pre class="programlisting"><span class="comment">//! Define a simple custom number</span>
    241. 

  241. <span class="keyword">struct</span> <span class="identifier">Double</span>
    242. 

  242.     <span class="special">:</span>   <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators</span>
    243. 

  243.         <span class="special">&lt;</span>
    244. 

  244.             <span class="identifier">Double</span>
    245. 

  245.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">long</span> <span class="keyword">double</span>
    246. 

  246.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">double</span>
    247. 

  247.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">float</span>
    248. 

  248.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">int</span>
    249. 

  249.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span>
    250. 

  250.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">long</span>
    251. 

  251.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">long</span>
    252. 

  252.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">long</span> <span class="keyword">long</span>
    253. 

  253.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="keyword">long</span>
    254. 

  254.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">char</span>
    255. 

  255.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">char</span>
    256. 

  256.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">short</span>
    257. 

  257.           <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ordered_field_operators2</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">short</span>
    258. 

  258.         <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="special">&gt;</span>
    259. 

  259. <span class="special">{</span>
    260. 

  260.     <span class="identifier">Double</span><span class="special">()</span>
    261. 

  261.         <span class="special">:</span> <span class="identifier">v</span><span class="special">(</span><span class="number">0</span><span class="special">)</span>
    262. 

  262.     <span class="special">{}</span>
    263. 

  263. 

  264.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    265. 

  265.     <span class="keyword">explicit</span> <span class="identifier">Double</span><span class="special">(</span> <span class="identifier">T</span> <span class="identifier">v</span> <span class="special">)</span>
    266. 

  266.         <span class="special">:</span> <span class="identifier">v</span><span class="special">(</span><span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">v</span><span class="special">))</span>
    267. 

  267.     <span class="special">{}</span>
    268. 

  268. 

  269.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    270. 

  270.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span> <span class="identifier">t</span> <span class="special">)</span>
    271. 

  271.     <span class="special">{</span>
    272. 

  272.         <span class="identifier">v</span> <span class="special">=</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">t</span><span class="special">);</span>
    273. 

  273.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    274. 

  274.     <span class="special">}</span>
    275. 

  275. 

  276.     <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">&lt;</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">const</span>
    277. 

  277.     <span class="special">{</span>
    278. 

  278.         <span class="keyword">return</span> <span class="identifier">v</span> <span class="special">&lt;</span> <span class="identifier">rhs</span><span class="special">.</span><span class="identifier">v</span><span class="special">;</span>
    279. 

  279.     <span class="special">}</span>
    280. 

  280. 

  281.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    282. 

  282.     <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">&lt;</span> <span class="special">(</span> <span class="identifier">T</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">const</span>
    283. 

  283.     <span class="special">{</span>
    284. 

  284.         <span class="keyword">return</span> <span class="identifier">v</span> <span class="special">&lt;</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">rhs</span><span class="special">);</span>
    285. 

  285.     <span class="special">}</span>
    286. 

  286. 

  287.     <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">&gt;</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">const</span>
    288. 

  288.     <span class="special">{</span>
    289. 

  289.         <span class="keyword">return</span> <span class="identifier">v</span> <span class="special">&gt;</span> <span class="identifier">rhs</span><span class="special">.</span><span class="identifier">v</span><span class="special">;</span>
    290. 

  290.     <span class="special">}</span>
    291. 

  291. 

  292.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    293. 

  293.     <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">&gt;</span> <span class="special">(</span> <span class="identifier">T</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">const</span>
    294. 

  294.     <span class="special">{</span>
    295. 

  295.         <span class="keyword">return</span> <span class="identifier">v</span> <span class="special">&gt;</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">rhs</span><span class="special">);</span>
    296. 

  296.     <span class="special">}</span>
    297. 

  297. 

  298.     <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">==(</span> <span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">const</span>
    299. 

  299.     <span class="special">{</span>
    300. 

  300.         <span class="keyword">return</span> <span class="identifier">v</span> <span class="special">==</span> <span class="identifier">rhs</span><span class="special">.</span><span class="identifier">v</span><span class="special">;</span>
    301. 

  301.     <span class="special">}</span>
    302. 

  302. 

  303.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    304. 

  304.     <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">==</span> <span class="special">(</span> <span class="identifier">T</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">const</span>
    305. 

  305.     <span class="special">{</span>
    306. 

  306.         <span class="keyword">return</span> <span class="identifier">v</span> <span class="special">==</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">rhs</span><span class="special">);</span>
    307. 

  307.     <span class="special">}</span>
    308. 

  308. 

  309.     <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">!()</span> <span class="keyword">const</span>
    310. 

  310.     <span class="special">{</span>
    311. 

  311.         <span class="keyword">return</span> <span class="identifier">v</span> <span class="special">==</span> <span class="number">0</span><span class="special">;</span>
    312. 

  312.     <span class="special">}</span>
    313. 

  313. 

  314.     <span class="identifier">Double</span> <span class="keyword">operator</span> <span class="special">-()</span> <span class="keyword">const</span>
    315. 

  315.     <span class="special">{</span>
    316. 

  316.         <span class="keyword">return</span> <span class="identifier">Double</span><span class="special">(-</span><span class="identifier">v</span><span class="special">);</span>
    317. 

  317.     <span class="special">}</span>
    318. 

  318. 

  319.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">+=(</span> <span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">t</span> <span class="special">)</span>
    320. 

  320.     <span class="special">{</span>
    321. 

  321.         <span class="identifier">v</span> <span class="special">+=</span> <span class="identifier">t</span><span class="special">.</span><span class="identifier">v</span><span class="special">;</span>
    322. 

  322.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    323. 

  323.     <span class="special">}</span>
    324. 

  324. 

  325.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    326. 

  326.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">+=(</span> <span class="identifier">T</span> <span class="identifier">t</span> <span class="special">)</span>
    327. 

  327.     <span class="special">{</span>
    328. 

  328.         <span class="identifier">v</span> <span class="special">+=</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">t</span><span class="special">);</span>
    329. 

  329.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    330. 

  330.     <span class="special">}</span>
    331. 

  331. 

  332.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">-=(</span> <span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">t</span> <span class="special">)</span>
    333. 

  333.     <span class="special">{</span>
    334. 

  334.         <span class="identifier">v</span> <span class="special">-=</span> <span class="identifier">t</span><span class="special">.</span><span class="identifier">v</span><span class="special">;</span>
    335. 

  335.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    336. 

  336.     <span class="special">}</span>
    337. 

  337. 

  338.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    339. 

  339.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">-=(</span> <span class="identifier">T</span> <span class="identifier">t</span> <span class="special">)</span>
    340. 

  340.     <span class="special">{</span>
    341. 

  341.         <span class="identifier">v</span> <span class="special">-=</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">t</span><span class="special">);</span>
    342. 

  342.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    343. 

  343.     <span class="special">}</span>
    344. 

  344. 

  345.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">*=</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">factor</span> <span class="special">)</span>
    346. 

  346.     <span class="special">{</span>
    347. 

  347.         <span class="identifier">v</span> <span class="special">*=</span> <span class="identifier">factor</span><span class="special">.</span><span class="identifier">v</span><span class="special">;</span>
    348. 

  348.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    349. 

  349.     <span class="special">}</span>
    350. 

  350. 

  351.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    352. 

  352.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">*=(</span> <span class="identifier">T</span> <span class="identifier">t</span> <span class="special">)</span>
    353. 

  353.     <span class="special">{</span>
    354. 

  354.         <span class="identifier">v</span> <span class="special">*=</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">t</span><span class="special">);</span>
    355. 

  355.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    356. 

  356.     <span class="special">}</span>
    357. 

  357. 

  358.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">/=</span> <span class="special">(</span><span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">divisor</span><span class="special">)</span>
    359. 

  359.     <span class="special">{</span>
    360. 

  360.         <span class="identifier">v</span> <span class="special">/=</span> <span class="identifier">divisor</span><span class="special">.</span><span class="identifier">v</span><span class="special">;</span>
    361. 

  361.         <span class="keyword">return</span> <span class="special">*</span><span class="keyword">this</span><span class="special">;</span>
    362. 

  362.     <span class="special">}</span>
    363. 

  363. 

  364.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    365. 

  365.     <span class="identifier">Double</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">/=(</span> <span class="identifier">T</span> <span class="identifier">t</span> <span class="special">)</span>
    366. 

  366.     <span class="special">{</span>
    367. 

  367.          <span class="identifier">v</span> <span class="special">/=</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;(</span><span class="identifier">t</span><span class="special">);</span>
    368. 

  368.         <span class="keyword">return</span> <span class="special">(*</span><span class="keyword">this</span><span class="special">);</span>
    369. 

  369.     <span class="special">}</span>
    370. 

  370. 

  371.     <span class="keyword">double</span> <span class="identifier">v</span><span class="special">;</span>
    372. 

  372. <span class="special">};</span>
    373. 

  373. 

  374. <span class="comment">//! Define numeric_limits for the custom type.</span>
    375. 

  375. <span class="keyword">namespace</span> <span class="identifier">std</span>
    376. 

  376. <span class="special">{</span>
    377. 

  377.     <span class="keyword">template</span><span class="special">&lt;&gt;</span>
    378. 

  378.     <span class="keyword">class</span> <span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">Double</span><span class="special">&gt;</span> <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;</span>
    379. 

  379.     <span class="special">{</span>
    380. 

  380.     <span class="keyword">public</span><span class="special">:</span>
    381. 

  381. 

  382.         <span class="comment">//! Limit our Double to a range of +/- 100.0</span>
    383. 

  383.         <span class="keyword">static</span> <span class="identifier">Double</span> <span class="special">(</span><span class="identifier">min</span><span class="special">)()</span>
    384. 

  384.         <span class="special">{</span>
    385. 

  385.             <span class="keyword">return</span> <span class="identifier">Double</span><span class="special">(</span><span class="number">1.e-2</span><span class="special">);</span>
    386. 

  386.         <span class="special">}</span>
    387. 

  387. 

  388.         <span class="keyword">static</span> <span class="identifier">Double</span> <span class="special">(</span><span class="identifier">max</span><span class="special">)()</span>
    389. 

  389.         <span class="special">{</span>
    390. 

  390.             <span class="keyword">return</span> <span class="identifier">Double</span><span class="special">(</span><span class="number">1.e2</span><span class="special">);</span>
    391. 

  391.         <span class="special">}</span>
    392. 

  392. 

  393.         <span class="keyword">static</span> <span class="identifier">Double</span> <span class="identifier">epsilon</span><span class="special">()</span>
    394. 

  394.         <span class="special">{</span>
    395. 

  395.             <span class="keyword">return</span> <span class="identifier">Double</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;::</span><span class="identifier">epsilon</span><span class="special">()</span> <span class="special">);</span>
    396. 

  396.         <span class="special">}</span>
    397. 

  397.     <span class="special">};</span>
    398. 

  398. <span class="special">}</span>
    399. 

  399. 

  400. <span class="comment">//! Define range checking and overflow policies.</span>
    401. 

  401. <span class="keyword">namespace</span> <span class="identifier">custom</span>
    402. 

  402. <span class="special">{</span>
    403. 

  403.     <span class="comment">//! Define a custom range checker</span>
    404. 

  404.     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Traits</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">OverFlowHandler</span><span class="special">&gt;</span>
    405. 

  405.     <span class="keyword">struct</span> <span class="identifier">range_checker</span>
    406. 

  406.     <span class="special">{</span>
    407. 

  407.         <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">Traits</span><span class="special">::</span><span class="identifier">argument_type</span> <span class="identifier">argument_type</span> <span class="special">;</span>
    408. 

  408.         <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">Traits</span><span class="special">::</span><span class="identifier">source_type</span> <span class="identifier">S</span><span class="special">;</span>
    409. 

  409.         <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">Traits</span><span class="special">::</span><span class="identifier">target_type</span> <span class="identifier">T</span><span class="special">;</span>
    410. 

  410. 

  411.         <span class="comment">//! Check range of integral types.</span>
    412. 

  412.         <span class="keyword">static</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">range_check_result</span> <span class="identifier">out_of_range</span><span class="special">(</span> <span class="identifier">argument_type</span> <span class="identifier">s</span> <span class="special">)</span>
    413. 

  413.         <span class="special">{</span>
    414. 

  414.             <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">;</span>
    415. 

  415.             <span class="keyword">if</span><span class="special">(</span> <span class="identifier">s</span> <span class="special">&gt;</span> <span class="identifier">bounds</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">highest</span><span class="special">()</span> <span class="special">)</span>
    416. 

  416.                 <span class="keyword">return</span> <span class="identifier">cPosOverflow</span><span class="special">;</span>
    417. 

  417.             <span class="keyword">else</span> <span class="keyword">if</span><span class="special">(</span> <span class="identifier">s</span> <span class="special">&lt;</span> <span class="identifier">bounds</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">lowest</span><span class="special">()</span> <span class="special">)</span>
    418. 

  418.                 <span class="keyword">return</span> <span class="identifier">cNegOverflow</span><span class="special">;</span>
    419. 

  419.             <span class="keyword">else</span>
    420. 

  420.                 <span class="keyword">return</span> <span class="identifier">cInRange</span><span class="special">;</span>
    421. 

  421.         <span class="special">}</span>
    422. 

  422. 

  423.         <span class="keyword">static</span> <span class="keyword">void</span> <span class="identifier">validate_range</span> <span class="special">(</span> <span class="identifier">argument_type</span> <span class="identifier">s</span> <span class="special">)</span>
    424. 

  424.         <span class="special">{</span>
    425. 

  425.             <span class="identifier">BOOST_STATIC_ASSERT</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">is_bounded</span> <span class="special">);</span>
    426. 

  426.             <span class="identifier">OverFlowHandler</span><span class="special">()(</span> <span class="identifier">out_of_range</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span> <span class="special">);</span>
    427. 

  427.         <span class="special">}</span>
    428. 

  428.     <span class="special">};</span>
    429. 

  429. 

  430.     <span class="comment">//! Overflow handler</span>
    431. 

  431.     <span class="keyword">struct</span> <span class="identifier">positive_overflow</span><span class="special">{};</span>
    432. 

  432.     <span class="keyword">struct</span> <span class="identifier">negative_overflow</span><span class="special">{};</span>
    433. 

  433. 

  434.     <span class="keyword">struct</span> <span class="identifier">overflow_handler</span>
    435. 

  435.     <span class="special">{</span>
    436. 

  436.         <span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()</span> <span class="special">(</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">range_check_result</span> <span class="identifier">r</span> <span class="special">)</span>
    437. 

  437.         <span class="special">{</span>
    438. 

  438.             <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">;</span>
    439. 

  439.             <span class="keyword">if</span><span class="special">(</span> <span class="identifier">r</span> <span class="special">==</span> <span class="identifier">cNegOverflow</span> <span class="special">)</span>
    440. 

  440.                 <span class="keyword">throw</span> <span class="identifier">negative_overflow</span><span class="special">()</span> <span class="special">;</span>
    441. 

  441.             <span class="keyword">else</span> <span class="keyword">if</span><span class="special">(</span> <span class="identifier">r</span> <span class="special">==</span> <span class="identifier">cPosOverflow</span> <span class="special">)</span>
    442. 

  442.                 <span class="keyword">throw</span> <span class="identifier">positive_overflow</span><span class="special">()</span> <span class="special">;</span>
    443. 

  443.         <span class="special">}</span>
    444. 

  444.     <span class="special">};</span>
    445. 

  445. 

  446.     <span class="comment">//! Define a rounding policy and specialize on the custom type.</span>
    447. 

  447.     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">S</span><span class="special">&gt;</span>
    448. 

  448.     <span class="keyword">struct</span> <span class="identifier">Ceil</span> <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">Ceil</span><span class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;{};</span>
    449. 

  449. 

  450.     <span class="keyword">template</span><span class="special">&lt;&gt;</span>
    451. 

  451.     <span class="keyword">struct</span> <span class="identifier">Ceil</span><span class="special">&lt;</span><span class="identifier">Double</span><span class="special">&gt;</span>
    452. 

  452.     <span class="special">{</span>
    453. 

  453.       <span class="keyword">typedef</span> <span class="identifier">Double</span> <span class="identifier">source_type</span><span class="special">;</span>
    454. 

  454. 

  455.       <span class="keyword">typedef</span> <span class="identifier">Double</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">argument_type</span><span class="special">;</span>
    456. 

  456. 

  457.       <span class="keyword">static</span> <span class="identifier">source_type</span> <span class="identifier">nearbyint</span> <span class="special">(</span> <span class="identifier">argument_type</span> <span class="identifier">s</span> <span class="special">)</span>
    458. 

  458.       <span class="special">{</span>
    459. 

  459. <span class="preprocessor">#if</span> <span class="special">!</span><span class="identifier">defined</span><span class="special">(</span><span class="identifier">BOOST_NO_STDC_NAMESPACE</span><span class="special">)</span>
    460. 

  460.           <span class="keyword">using</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">ceil</span> <span class="special">;</span>
    461. 

  461. <span class="preprocessor">#endif</span>
    462. 

  462.           <span class="keyword">return</span> <span class="identifier">Double</span><span class="special">(</span> <span class="identifier">ceil</span><span class="special">(</span><span class="identifier">s</span><span class="special">.</span><span class="identifier">v</span><span class="special">)</span> <span class="special">);</span>
    463. 

  463.       <span class="special">}</span>
    464. 

  464. 

  465.       <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">integral_c</span><span class="special">&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">float_round_style</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">round_toward_infinity</span><span class="special">&gt;</span> <span class="identifier">round_style</span><span class="special">;</span>
    466. 

  466.     <span class="special">};</span>
    467. 

  467. 

  468.     <span class="comment">//! Define a rounding policy and specialize on the custom type.</span>
    469. 

  469.     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">S</span><span class="special">&gt;</span>
    470. 

  470.     <span class="keyword">struct</span> <span class="identifier">Trunc</span><span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">Trunc</span><span class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;{};</span>
    471. 

  471. 

  472.     <span class="keyword">template</span><span class="special">&lt;&gt;</span>
    473. 

  473.     <span class="keyword">struct</span> <span class="identifier">Trunc</span><span class="special">&lt;</span><span class="identifier">Double</span><span class="special">&gt;</span>
    474. 

  474.     <span class="special">{</span>
    475. 

  475.       <span class="keyword">typedef</span> <span class="identifier">Double</span> <span class="identifier">source_type</span><span class="special">;</span>
    476. 

  476. 

  477.       <span class="keyword">typedef</span> <span class="identifier">Double</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">argument_type</span><span class="special">;</span>
    478. 

  478. 

  479.       <span class="keyword">static</span> <span class="identifier">source_type</span> <span class="identifier">nearbyint</span> <span class="special">(</span> <span class="identifier">argument_type</span> <span class="identifier">s</span> <span class="special">)</span>
    480. 

  480.       <span class="special">{</span>
    481. 

  481. <span class="preprocessor">#if</span> <span class="special">!</span><span class="identifier">defined</span><span class="special">(</span><span class="identifier">BOOST_NO_STDC_NAMESPACE</span><span class="special">)</span>
    482. 

  482.           <span class="keyword">using</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">floor</span><span class="special">;</span>
    483. 

  483. <span class="preprocessor">#endif</span>
    484. 

  484.           <span class="keyword">return</span> <span class="identifier">Double</span><span class="special">(</span> <span class="identifier">floor</span><span class="special">(</span><span class="identifier">s</span><span class="special">.</span><span class="identifier">v</span><span class="special">)</span> <span class="special">);</span>
    485. 

  485.       <span class="special">}</span>
    486. 

  486. 

  487.       <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">integral_c</span><span class="special">&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">float_round_style</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">round_toward_zero</span><span class="special">&gt;</span> <span class="identifier">round_style</span><span class="special">;</span>
    488. 

  488.     <span class="special">};</span>
    489. 

  489. <span class="special">}//</span><span class="keyword">namespace</span> <span class="identifier">custom</span><span class="special">;</span>
    490. 

  490. 

  491. <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>
    492. 

  492. 

  493.     <span class="comment">//! Define the numeric_cast_traits specializations on the custom type.</span>
    494. 

  494.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">S</span><span class="special">&gt;</span>
    495. 

  495.     <span class="keyword">struct</span> <span class="identifier">numeric_cast_traits</span><span class="special">&lt;</span><span class="identifier">Double</span><span class="special">,</span> <span class="identifier">S</span><span class="special">&gt;</span>
    496. 

  496.     <span class="special">{</span>
    497. 

  497.         <span class="keyword">typedef</span> <span class="identifier">custom</span><span class="special">::</span><span class="identifier">overflow_handler</span>                         <span class="identifier">overflow_policy</span><span class="special">;</span>
    498. 

  498.         <span class="keyword">typedef</span> <span class="identifier">custom</span><span class="special">::</span><span class="identifier">range_checker</span>
    499. 

  499.                 <span class="special">&lt;</span>
    500. 

  500.                     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">conversion_traits</span><span class="special">&lt;</span><span class="identifier">Double</span><span class="special">,</span> <span class="identifier">S</span><span class="special">&gt;</span>
    501. 

  501.                   <span class="special">,</span> <span class="identifier">overflow_policy</span>
    502. 

  502.                 <span class="special">&gt;</span>                                                <span class="identifier">range_checking_policy</span><span class="special">;</span>
    503. 

  503.         <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">Trunc</span><span class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;</span>                         <span class="identifier">rounding_policy</span><span class="special">;</span>
    504. 

  504.     <span class="special">};</span>
    505. 

  505. 

  506.     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    507. 

  507.     <span class="keyword">struct</span> <span class="identifier">numeric_cast_traits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">Double</span><span class="special">&gt;</span>
    508. 

  508.     <span class="special">{</span>
    509. 

  509.         <span class="keyword">typedef</span> <span class="identifier">custom</span><span class="special">::</span><span class="identifier">overflow_handler</span>                         <span class="identifier">overflow_policy</span><span class="special">;</span>
    510. 

  510.         <span class="keyword">typedef</span> <span class="identifier">custom</span><span class="special">::</span><span class="identifier">range_checker</span>
    511. 

  511.                 <span class="special">&lt;</span>
    512. 

  512.                     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">conversion_traits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">Double</span><span class="special">&gt;</span>
    513. 

  513.                   <span class="special">,</span> <span class="identifier">overflow_policy</span>
    514. 

  514.                 <span class="special">&gt;</span>                                                <span class="identifier">range_checking_policy</span><span class="special">;</span>
    515. 

  515.         <span class="keyword">typedef</span> <span class="identifier">custom</span><span class="special">::</span><span class="identifier">Trunc</span><span class="special">&lt;</span><span class="identifier">Double</span><span class="special">&gt;</span>                            <span class="identifier">rounding_policy</span><span class="special">;</span>
    516. 

  516.     <span class="special">};</span>
    517. 

  517. 

  518.     <span class="comment">//! Define the conversion from the custom type to built-in types and vice-versa.</span>
    519. 

  519.     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
    520. 

  520.     <span class="keyword">struct</span> <span class="identifier">raw_converter</span><span class="special">&lt;</span> <span class="identifier">conversion_traits</span><span class="special">&lt;</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">Double</span> <span class="special">&gt;</span> <span class="special">&gt;</span>
    521. 

  521.     <span class="special">{</span>
    522. 

  522.         <span class="keyword">static</span> <span class="identifier">T</span> <span class="identifier">low_level_convert</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">Double</span><span class="special">&amp;</span> <span class="identifier">n</span> <span class="special">)</span>
    523. 

  523.         <span class="special">{</span>
    524. 

  524.             <span class="keyword">return</span> <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;(</span> <span class="identifier">n</span><span class="special">.</span><span class="identifier">v</span> <span class="special">);</span>
    525. 

  525.         <span class="special">}</span>
    526. 

  526.     <span class="special">};</span>
    527. 

  527. 

  528.     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">S</span><span class="special">&gt;</span>
    529. 

  529.     <span class="keyword">struct</span> <span class="identifier">raw_converter</span><span class="special">&lt;</span> <span class="identifier">conversion_traits</span><span class="special">&lt;</span> <span class="identifier">Double</span><span class="special">,</span> <span class="identifier">S</span> <span class="special">&gt;</span> <span class="special">&gt;</span>
    530. 

  530.     <span class="special">{</span>
    531. 

  531.         <span class="keyword">static</span> <span class="identifier">Double</span> <span class="identifier">low_level_convert</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">S</span><span class="special">&amp;</span> <span class="identifier">n</span> <span class="special">)</span>
    532. 

  532.         <span class="special">{</span>
    533. 

  533.             <span class="keyword">return</span> <span class="identifier">Double</span><span class="special">(</span><span class="identifier">n</span><span class="special">);</span>
    534. 

  534.         <span class="special">}</span>
    535. 

  535.     <span class="special">};</span>
    536. 

  536. <span class="special">}}//</span><span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">;</span>
    537. 

  537. </pre>
    538. 

  538. </div>
    539. 

  539. </div>
    540. 

  540. <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
    541. 

  541. <td align="left"></td>
    542. 

  542. <td align="right"><div class="copyright-footer">Copyright &#169; 2004-2007 Fernando
    543. 

  543.       Luis Cacciola Carballal<p>
    544. 

  544.         Distributed under the Boost Software License, Version 1.0. (See accompanying
    545. 

  545.         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>)
    546. 

  546.       </p>
    547. 

  547. </div></td>
    548. 

  548. </tr></table>
    549. 

  549. <hr>
    550. 

  550. <div class="spirit-nav">
    551. 

  551. <a accesskey="p" href="converter___function_object.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="bounds___traits_class.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
    552. 

  552. </div>
    553. 

  553. </body>
    554. 

  554. </html>
    555.