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<div class="header">
  <div class="headertitle"><div class="title">CacheHeader Struct Reference</div></div>
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<p>Cache top-level descriptor encapsulating the hash table root and capacity limit.  
 <a href="#details">More...</a></p>

<p><code>#include &lt;<a class="el" href="lru_8h_source.html">aaruformat/lru.h</a>&gt;</code></p>
<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 id="header-pub-attribs" class="groupheader"><a id="pub-attribs" name="pub-attribs"></a>
Data Fields</h2></td></tr>
<tr class="memitem:af82718ebf5e59a398bc6e9428a389bb2" id="r_af82718ebf5e59a398bc6e9428a389bb2"><td class="memItemLeft">uint64_t&#160;</td><td class="memItemRight"><a class="el" href="#af82718ebf5e59a398bc6e9428a389bb2">max_bytes</a></td></tr>
<tr class="memdesc:af82718ebf5e59a398bc6e9428a389bb2"><td class="mdescLeft">&#160;</td><td class="mdescRight">Memory budget in bytes for the cached values. 0 means unlimited.  <br /></td></tr>
<tr class="memitem:ae6521ccf8e75b0c9c70297af637b1eaa" id="r_ae6521ccf8e75b0c9c70297af637b1eaa"><td class="memItemLeft">uint64_t&#160;</td><td class="memItemRight"><a class="el" href="#ae6521ccf8e75b0c9c70297af637b1eaa">cur_bytes</a></td></tr>
<tr class="memdesc:ae6521ccf8e75b0c9c70297af637b1eaa"><td class="mdescLeft">&#160;</td><td class="mdescRight">Bytes currently held by the cached values.  <br /></td></tr>
<tr class="memitem:a44229bb929d8949f3c2700d07123d224" id="r_a44229bb929d8949f3c2700d07123d224"><td class="memItemLeft">struct <a class="el" href="structCacheEntry.html">CacheEntry</a> *&#160;</td><td class="memItemRight"><a class="el" href="#a44229bb929d8949f3c2700d07123d224">cache</a></td></tr>
<tr class="memdesc:a44229bb929d8949f3c2700d07123d224"><td class="mdescLeft">&#160;</td><td class="mdescRight">Hash root (uthash). NULL when empty.  <br /></td></tr>
<tr class="memitem:a54d553e78f5d90cce34ee684829a410f" id="r_a54d553e78f5d90cce34ee684829a410f"><td class="memItemLeft">void(*)&#160;</td><td class="memItemRight"><a class="el" href="#a54d553e78f5d90cce34ee684829a410f">free_func</a> (void *)</td></tr>
<tr class="memdesc:a54d553e78f5d90cce34ee684829a410f"><td class="mdescLeft">&#160;</td><td class="mdescRight">Optional callback to free cached values. NULL if not needed.  <br /></td></tr>
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<a name="details" id="details"></a><h2 id="header-details" class="groupheader">Detailed Description</h2>
<div class="textblock"><p>Cache top-level descriptor encapsulating the hash table root and capacity limit. </p>
<p>The cache is bounded by the total number of <em>bytes</em> held by its values, not by the number of entries: the caches in this library store values of wildly different sizes (a block header is a few dozen bytes, a decompressed data block is megabytes), so an entry-count limit cannot express a memory budget. On insert, the least recently used entries are evicted until the cache is back under max_bytes.</p>
<p>Fields:</p><ul>
<li>max_bytes: Memory budget in bytes; 0 means unlimited.</li>
<li>cur_bytes: Bytes currently held by the cached values.</li>
<li>cache: uthash root pointer; NULL when the cache is empty.</li>
<li>free_func: Optional callback to free cached values on eviction/clear.</li>
</ul>
<p>The entry just inserted is never evicted, so a caller may keep using the pointer it handed over for the remainder of the call even if the value is larger than max_bytes. </p>

<p class="definition">Definition at line <a class="el" href="lru_8h_source.html#l00050">50</a> of file <a class="el" href="lru_8h_source.html">lru.h</a>.</p>
</div><a name="doc-variable-members" id="doc-variable-members"></a><h2 id="header-doc-variable-members" class="groupheader">Field Documentation</h2>
<a id="a44229bb929d8949f3c2700d07123d224" name="a44229bb929d8949f3c2700d07123d224"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a44229bb929d8949f3c2700d07123d224">&#9670;&#160;</a></span>cache</h2>

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          <td class="memname">struct <a class="el" href="structCacheEntry.html">CacheEntry</a>* CacheHeader::cache</td>
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<p>Hash root (uthash). NULL when empty. </p>

<p class="definition">Definition at line <a class="el" href="lru_8h_source.html#l00054">54</a> of file <a class="el" href="lru_8h_source.html">lru.h</a>.</p>

<p class="reference">Referenced by <a class="el" href="create_8c_source.html#l00291">aaruf_create()</a>, <a class="el" href="open_8c_source.html#l00236">aaruf_open()</a>, <a class="el" href="lru_8c_source.html#l00068">add_to_cache_uint64()</a>, <a class="el" href="lru_8c_source.html#l00020">drop_entry()</a>, <a class="el" href="lru_8c_source.html#l00041">find_in_cache_uint64()</a>, and <a class="el" href="lru_8c_source.html#l00118">free_cache()</a>.</p>

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<a id="ae6521ccf8e75b0c9c70297af637b1eaa" name="ae6521ccf8e75b0c9c70297af637b1eaa"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ae6521ccf8e75b0c9c70297af637b1eaa">&#9670;&#160;</a></span>cur_bytes</h2>

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          <td class="memname">uint64_t CacheHeader::cur_bytes</td>
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<p>Bytes currently held by the cached values. </p>

<p class="definition">Definition at line <a class="el" href="lru_8h_source.html#l00053">53</a> of file <a class="el" href="lru_8h_source.html">lru.h</a>.</p>

<p class="reference">Referenced by <a class="el" href="create_8c_source.html#l00291">aaruf_create()</a>, <a class="el" href="open_8c_source.html#l00236">aaruf_open()</a>, <a class="el" href="lru_8c_source.html#l00068">add_to_cache_uint64()</a>, <a class="el" href="lru_8c_source.html#l00020">drop_entry()</a>, and <a class="el" href="lru_8c_source.html#l00118">free_cache()</a>.</p>

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<a id="a54d553e78f5d90cce34ee684829a410f" name="a54d553e78f5d90cce34ee684829a410f"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a54d553e78f5d90cce34ee684829a410f">&#9670;&#160;</a></span>free_func</h2>

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          <td class="memname">void(*) CacheHeader::free_func(void *)</td>
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<p>Optional callback to free cached values. NULL if not needed. </p>

<p class="definition">Definition at line <a class="el" href="lru_8h_source.html#l00055">55</a> of file <a class="el" href="lru_8h_source.html">lru.h</a>.</p>

<p class="reference">Referenced by <a class="el" href="create_8c_source.html#l00291">aaruf_create()</a>, <a class="el" href="open_8c_source.html#l00236">aaruf_open()</a>, <a class="el" href="lru_8c_source.html#l00068">add_to_cache_uint64()</a>, and <a class="el" href="lru_8c_source.html#l00020">drop_entry()</a>.</p>

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<a id="af82718ebf5e59a398bc6e9428a389bb2" name="af82718ebf5e59a398bc6e9428a389bb2"></a>
<h2 class="memtitle"><span class="permalink"><a href="#af82718ebf5e59a398bc6e9428a389bb2">&#9670;&#160;</a></span>max_bytes</h2>

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          <td class="memname">uint64_t CacheHeader::max_bytes</td>
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<p>Memory budget in bytes for the cached values. 0 means unlimited. </p>

<p class="definition">Definition at line <a class="el" href="lru_8h_source.html#l00052">52</a> of file <a class="el" href="lru_8h_source.html">lru.h</a>.</p>

<p class="reference">Referenced by <a class="el" href="create_8c_source.html#l00291">aaruf_create()</a>, <a class="el" href="open_8c_source.html#l00236">aaruf_open()</a>, and <a class="el" href="lru_8c_source.html#l00068">add_to_cache_uint64()</a>.</p>

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<hr/>The documentation for this struct was generated from the following file:<ul>
<li>include/aaruformat/<a class="el" href="lru_8h_source.html">lru.h</a></li>
</ul>
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