<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE concept PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
  "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
<!--
  Hamigaki Library Document Source

  Copyright Takeshi Mouri 2006, 2007.
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE_1_0.txt or copy at
  http://www.boost.org/LICENSE_1_0.txt)
-->
<concept name="Extractor" category="Archivers">
  <param name="E" role="device-type"/>

  <associated-type name="header_type">
    <get-member-type name="header_type">
      <type name="E"/>
    </get-member-type>
    <description><simpara>ヘッダ情報を保持する型</simpara></description>
  </associated-type>

  <refines const="no" concept="Source"/>

  <notation variables="e">
    <sample-value>
      <type name="E"/>
    </sample-value>
  </notation>

  <notation variables="head">
    <sample-value>
      <type name="header_type"/>
    </sample-value>
  </notation>

  <valid-expression name="Switch the next entry">
    <apply-method name="next_entry">
      <sample-value><reference-to><type name="E"/></reference-to></sample-value>
    </apply-method>
    <return-type><require-same-type><type name="bool"/></require-same-type></return-type>
    <semantics><code>e</code>の読み込み対象を次のエントリに切り替える。</semantics>
  </valid-expression>

  <valid-expression name="Entry header">
    <apply-method name="header">
      <sample-value><reference-to><type name="E"/></reference-to></sample-value>
    </apply-method>
    <return-type><require-same-type><type name="header_type"/></require-same-type></return-type>
    <semantics><code>a</code>の現在のエントリのヘッダ情報を返す。</semantics>
  </valid-expression>
</concept>
