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<h3>Methods</h3>
<ul class="link-list" role="directory">
<li ><a href="#method-c-from">::from</a>
<li ><a href="#method-c-new">::new</a>
<li ><a href="#method-c-oct_or_256based">::oct_or_256based</a>
<li ><a href="#method-c-strict_oct">::strict_oct</a>
<li ><a href="#method-i-calculate_checksum">#calculate_checksum</a>
<li ><a href="#method-i-empty-3F">#empty?</a>
<li ><a href="#method-i-header">#header</a>
<li ><a href="#method-i-oct">#oct</a>
<li ><a href="#method-i-update_checksum">#update_checksum</a>
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<main role="main" aria-labelledby="class-Gem::Package::TarHeader">
<h1 id="class-Gem::Package::TarHeader" class="class">
class Gem::Package::TarHeader
</h1>
<section class="description">
<p>A header for a tar file</p>
</section>
<section id="5Buntitled-5D" class="documentation-section">
<section class="constants-list">
<header>
<h3>Constants</h3>
</header>
<dl>
<dt id="FIELDS">FIELDS
<dd><p>Fields in the tar header</p>
<dt id="PACK_FORMAT">PACK_FORMAT
<dd><p>Pack format for a tar header</p>
<dt id="UNPACK_FORMAT">UNPACK_FORMAT
<dd><p>Unpack format for a tar header</p>
</dl>
</section>
<section id="public-class-5Buntitled-5D-method-details" class="method-section">
<header>
<h3>Public Class Methods</h3>
</header>
<div id="method-c-from" class="method-detail ">
<div class="method-heading">
<span class="method-name">from</span><span
class="method-args">(stream)</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<p>Creates a tar header from <a href="../../IO.html"><code>IO</code></a> <code>stream</code></p>
<div class="method-source-code" id="from-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 101</span>
<span class="ruby-keyword">def</span> <span class="ruby-keyword">self</span>.<span class="ruby-identifier ruby-title">from</span>(<span class="ruby-identifier">stream</span>)
<span class="ruby-identifier">header</span> = <span class="ruby-identifier">stream</span>.<span class="ruby-identifier">read</span> <span class="ruby-value">512</span>
<span class="ruby-identifier">empty</span> = (<span class="ruby-constant">EMPTY_HEADER</span> <span class="ruby-operator">==</span> <span class="ruby-identifier">header</span>)
<span class="ruby-identifier">fields</span> = <span class="ruby-identifier">header</span>.<span class="ruby-identifier">unpack</span> <span class="ruby-constant">UNPACK_FORMAT</span>
<span class="ruby-identifier">new</span> <span class="ruby-value">:name</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>,
<span class="ruby-value">:mode</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:uid</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">oct_or_256based</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:gid</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">oct_or_256based</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:size</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:mtime</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:checksum</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:typeflag</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>,
<span class="ruby-value">:linkname</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>,
<span class="ruby-value">:magic</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>,
<span class="ruby-value">:version</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:uname</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>,
<span class="ruby-value">:gname</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>,
<span class="ruby-value">:devmajor</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:devminor</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>),
<span class="ruby-value">:prefix</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">fields</span>.<span class="ruby-identifier">shift</span>,
<span class="ruby-value">:empty</span> <span class="ruby-operator">=></span> <span class="ruby-identifier">empty</span>
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
<div id="method-c-new" class="method-detail ">
<div class="method-heading">
<span class="method-name">new</span><span
class="method-args">(vals)</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<p>Creates a new <a href="TarHeader.html"><code>TarHeader</code></a> using <code>vals</code></p>
<div class="method-source-code" id="new-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 144</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">initialize</span>(<span class="ruby-identifier">vals</span>)
<span class="ruby-keyword">unless</span> <span class="ruby-identifier">vals</span>[<span class="ruby-value">:name</span>] <span class="ruby-operator">&&</span> <span class="ruby-identifier">vals</span>[<span class="ruby-value">:size</span>] <span class="ruby-operator">&&</span> <span class="ruby-identifier">vals</span>[<span class="ruby-value">:prefix</span>] <span class="ruby-operator">&&</span> <span class="ruby-identifier">vals</span>[<span class="ruby-value">:mode</span>]
<span class="ruby-identifier">raise</span> <span class="ruby-constant">ArgumentError</span>, <span class="ruby-string">":name, :size, :prefix and :mode required"</span>
<span class="ruby-keyword">end</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:uid</span>] <span class="ruby-operator">||=</span> <span class="ruby-value">0</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:gid</span>] <span class="ruby-operator">||=</span> <span class="ruby-value">0</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:mtime</span>] <span class="ruby-operator">||=</span> <span class="ruby-value">0</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:checksum</span>] <span class="ruby-operator">||=</span> <span class="ruby-string">""</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:typeflag</span>] = <span class="ruby-string">"0"</span> <span class="ruby-keyword">if</span> <span class="ruby-identifier">vals</span>[<span class="ruby-value">:typeflag</span>].<span class="ruby-identifier">nil?</span> <span class="ruby-operator">||</span> <span class="ruby-identifier">vals</span>[<span class="ruby-value">:typeflag</span>].<span class="ruby-identifier">empty?</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:magic</span>] <span class="ruby-operator">||=</span> <span class="ruby-string">"ustar"</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:version</span>] <span class="ruby-operator">||=</span> <span class="ruby-string">"00"</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:uname</span>] <span class="ruby-operator">||=</span> <span class="ruby-string">"wheel"</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:gname</span>] <span class="ruby-operator">||=</span> <span class="ruby-string">"wheel"</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:devmajor</span>] <span class="ruby-operator">||=</span> <span class="ruby-value">0</span>
<span class="ruby-identifier">vals</span>[<span class="ruby-value">:devminor</span>] <span class="ruby-operator">||=</span> <span class="ruby-value">0</span>
<span class="ruby-constant">FIELDS</span>.<span class="ruby-identifier">each</span> <span class="ruby-keyword">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">name</span><span class="ruby-operator">|</span>
<span class="ruby-identifier">instance_variable_set</span> <span class="ruby-node">"@#{name}"</span>, <span class="ruby-identifier">vals</span>[<span class="ruby-identifier">name</span>]
<span class="ruby-keyword">end</span>
<span class="ruby-ivar">@empty</span> = <span class="ruby-identifier">vals</span>[<span class="ruby-value">:empty</span>]
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
<div id="method-c-oct_or_256based" class="method-detail ">
<div class="method-heading">
<span class="method-name">oct_or_256based</span><span
class="method-args">(str)</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<div class="method-source-code" id="oct_or_256based-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 132</span>
<span class="ruby-keyword">def</span> <span class="ruby-keyword">self</span>.<span class="ruby-identifier ruby-title">oct_or_256based</span>(<span class="ruby-identifier">str</span>)
<span class="ruby-comment"># \x80 flags a positive 256-based number</span>
<span class="ruby-comment"># \ff flags a negative 256-based number</span>
<span class="ruby-comment"># In case we have a match, parse it as a signed binary value</span>
<span class="ruby-comment"># in big-endian order, except that the high-order bit is ignored.</span>
<span class="ruby-keyword">return</span> <span class="ruby-identifier">str</span>.<span class="ruby-identifier">unpack</span>(<span class="ruby-string">'N2'</span>).<span class="ruby-identifier">last</span> <span class="ruby-keyword">if</span> <span class="ruby-identifier">str</span> <span class="ruby-operator">=~</span> <span class="ruby-regexp">/\A[\x80\xff]/n</span>
<span class="ruby-identifier">strict_oct</span>(<span class="ruby-identifier">str</span>)
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
<div id="method-c-strict_oct" class="method-detail ">
<div class="method-heading">
<span class="method-name">strict_oct</span><span
class="method-args">(str)</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<div class="method-source-code" id="strict_oct-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 127</span>
<span class="ruby-keyword">def</span> <span class="ruby-keyword">self</span>.<span class="ruby-identifier ruby-title">strict_oct</span>(<span class="ruby-identifier">str</span>)
<span class="ruby-keyword">return</span> <span class="ruby-identifier">str</span>.<span class="ruby-identifier">oct</span> <span class="ruby-keyword">if</span> <span class="ruby-identifier">str</span> <span class="ruby-operator">=~</span> <span class="ruby-regexp">/\A[0-7]*\z/</span>
<span class="ruby-identifier">raise</span> <span class="ruby-constant">ArgumentError</span>, <span class="ruby-node">"#{str.inspect} is not an octal string"</span>
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
</section>
<section id="public-instance-5Buntitled-5D-method-details" class="method-section">
<header>
<h3>Public Instance Methods</h3>
</header>
<div id="method-i-empty-3F" class="method-detail ">
<div class="method-heading">
<span class="method-name">empty?</span><span
class="method-args">()</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<p>Is the tar entry empty?</p>
<div class="method-source-code" id="empty-3F-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 171</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">empty?</span>
<span class="ruby-ivar">@empty</span>
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
<div id="method-i-update_checksum" class="method-detail ">
<div class="method-heading">
<span class="method-name">update_checksum</span><span
class="method-args">()</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<p>Updates the TarHeader's checksum</p>
<div class="method-source-code" id="update_checksum-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 203</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">update_checksum</span>
<span class="ruby-identifier">header</span> = <span class="ruby-identifier">header</span> <span class="ruby-string">" "</span> <span class="ruby-operator">*</span> <span class="ruby-value">8</span>
<span class="ruby-ivar">@checksum</span> = <span class="ruby-identifier">oct</span> <span class="ruby-identifier">calculate_checksum</span>(<span class="ruby-identifier">header</span>), <span class="ruby-value">6</span>
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
</section>
<section id="private-instance-5Buntitled-5D-method-details" class="method-section">
<header>
<h3>Private Instance Methods</h3>
</header>
<div id="method-i-calculate_checksum" class="method-detail ">
<div class="method-heading">
<span class="method-name">calculate_checksum</span><span
class="method-args">(header)</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<div class="method-source-code" id="calculate_checksum-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 210</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">calculate_checksum</span>(<span class="ruby-identifier">header</span>)
<span class="ruby-identifier">header</span>.<span class="ruby-identifier">unpack</span>(<span class="ruby-string">"C*"</span>).<span class="ruby-identifier">inject</span> { <span class="ruby-operator">|</span><span class="ruby-identifier">a</span>, <span class="ruby-identifier">b</span><span class="ruby-operator">|</span> <span class="ruby-identifier">a</span> <span class="ruby-operator">+</span> <span class="ruby-identifier">b</span> }
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
<div id="method-i-header" class="method-detail ">
<div class="method-heading">
<span class="method-name">header</span><span
class="method-args">(checksum = @checksum)</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<div class="method-source-code" id="header-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 214</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">header</span>(<span class="ruby-identifier">checksum</span> = <span class="ruby-ivar">@checksum</span>)
<span class="ruby-identifier">header</span> = [
<span class="ruby-identifier">name</span>,
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">mode</span>, <span class="ruby-value">7</span>),
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">uid</span>, <span class="ruby-value">7</span>),
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">gid</span>, <span class="ruby-value">7</span>),
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">size</span>, <span class="ruby-value">11</span>),
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">mtime</span>, <span class="ruby-value">11</span>),
<span class="ruby-identifier">checksum</span>,
<span class="ruby-string">" "</span>,
<span class="ruby-identifier">typeflag</span>,
<span class="ruby-identifier">linkname</span>,
<span class="ruby-identifier">magic</span>,
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">version</span>, <span class="ruby-value">2</span>),
<span class="ruby-identifier">uname</span>,
<span class="ruby-identifier">gname</span>,
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">devmajor</span>, <span class="ruby-value">7</span>),
<span class="ruby-identifier">oct</span>(<span class="ruby-identifier">devminor</span>, <span class="ruby-value">7</span>),
<span class="ruby-identifier">prefix</span>
]
<span class="ruby-identifier">header</span> = <span class="ruby-identifier">header</span>.<span class="ruby-identifier">pack</span> <span class="ruby-constant">PACK_FORMAT</span>
<span class="ruby-identifier">header</span> <span class="ruby-operator"><<</span> (<span class="ruby-string">"\0"</span> <span class="ruby-operator">*</span> ((<span class="ruby-value">512</span> <span class="ruby-operator">-</span> <span class="ruby-identifier">header</span>.<span class="ruby-identifier">size</span>) <span class="ruby-operator">%</span> <span class="ruby-value">512</span>))
<span class="ruby-keyword">end</span></pre>
</div>
</div>
</div>
<div id="method-i-oct" class="method-detail ">
<div class="method-heading">
<span class="method-name">oct</span><span
class="method-args">(num, len)</span>
<span class="method-click-advice">click to toggle source</span>
</div>
<div class="method-description">
<div class="method-source-code" id="oct-source">
<pre><span class="ruby-comment"># File lib/rubygems/package/tar_header.rb, line 240</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">oct</span>(<span class="ruby-identifier">num</span>, <span class="ruby-identifier">len</span>)
<span class="ruby-node">"%0#{len}o"</span> <span class="ruby-operator">%</span> <span class="ruby-identifier">num</span>
<span class="ruby-keyword">end</span></pre>
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