docs/c_glib/arrow-glib/method.StreamDecoder.get_next_required_size.html - arrow-site - Git at Google

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     <h3>Method</h3>
     <h1><a href="index.html">Arrow</a><span class="sep"></span><a href="class.StreamDecoder.html">StreamDecoder</a><span class="sep"></span>get_next_required_size</h1>
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       <p><span class="emblem available">since: 18.0.0</span></p>
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       <h4 style="display:flex;" id="declaration">
         Declaration
         <a class="anchor" href="#declaration"></a>

         <a class="srclink" title="go to source location" href="https://github.com/apache/arrow/blob/main/c_glib/arrow-glib/decoder.h#L94">[src]</a>

       </h4>

       <div class="docblock c-decl">
         <pre><code><div class="highlight"><pre><span></span><span class="n">gsize</span>
 <span class="n">garrow_stream_decoder_get_next_required_size</span><span class="w"> </span><span class="p">(</span>
 <span class="w">  </span><span class="n">GArrowStreamDecoder</span><span class="o">*</span><span class="w"> </span><span class="n">decoder</span>
 <span class="p">)</span>
 </pre></div>
 </code></pre>
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       <h4 style="display:flex;" id="description">
         Description
         <a class="anchor" href="#description"></a>

         <a class="srclink" title="go to source location" href="https://github.com/apache/arrow/blob/main/c_glib/arrow-glib/decoder.cpp#L509">[src]</a>

       </h4>

       <div class="docblock">
         <p>This method is provided for users who want to optimize performance.
 Normal users don&#8217;t need to use this&nbsp;method.</p>
 <p>Here is an example usage for normal&nbsp;users:</p>
 <div class="codehilite"><pre><span></span><code>garrow_stream_decoder_consume_buffer(decoder, buffer1);
 garrow_stream_decoder_consume_buffer(decoder, buffer2);
 garrow_stream_decoder_consume_buffer(decoder, buffer3);
 </code></pre></div>

 <p>Decoder has internal buffer. If consumed data isn&#8217;t enough to
 advance the state of the decoder, consumed data is buffered to
 the internal buffer. It causes performance&nbsp;overhead.</p>
 <p>If you pass <code>garrow_stream_decoer_get_next_required_size()</code> size data
 to each
 garrow_stream_decoder_consume_bytes()/garrow_stream_decoder_consume_buffer()
 call, the decoder doesn&#8217;t use its internal buffer. It improves&nbsp;performance.</p>
 <p>Here is an example usage to avoid using internal&nbsp;buffer:</p>
 <div class="codehilite"><pre><span></span><code>buffer1 = get_data(garrow_stream_decoder_get_next_required_size(decoder));
 garrow_stream_decoder_consume_buffer(buffer1);
 buffer2 = get_data(garrow_stream_decoder_get_next_required_size(decoder));
 garrow_stream_decoder_consume_buffer(buffer2);
 </code></pre></div>

 <p>Users can use this method to avoid creating small chunks. Record
 batch data must be contiguous data. If users pass small chunks to
 the decoder, the decoder needs concatenate small chunks
 internally. It causes performance&nbsp;overhead.</p>
 <p>Here is an example usage to reduce small&nbsp;chunks:</p>
 <div class="codehilite"><pre><span></span><code>GArrowResizablBuffer *buffer = garrow_resizable_buffer_new(1024, NULL);
 while ((small_chunk = get_data(&amp;small_chunk_size))) {
   size_t current_buffer_size = garrow_buffer_get_size(GARROW_BUFFER(buffer));
   garrow_resizable_buffer_resize(buffer, current_buffer_size + small_chunk_size,
 </code></pre></div>

 <p><span class="caps">NULL</span>);
       garrow_mutable_buffer_set_data(GARROW_MUTABLE_BUFFER(buffer),
                                      current_buffer_size,
                                      small_chunk,
                                      small_chunk_size,
                                      <span class="caps">NULL</span>);
       if (garrow_buffer_get_size(GARROW_BUFFER(buffer)) &lt;
           garrow_stream_decoder_get_next_required_size(decoder)) {
         continue;
       }
       garrow_stream_decoder_consume_buffer(decoder, GARROW_BUFFER(buffer), <span class="caps">NULL</span>);
       g_object_unref(buffer);
       buffer = garrow_resizable_buffer_new(1024, <span class="caps">NULL</span>);
     }
     if (garrow_buffer_get_size(GARROW_BUFFER(buffer)) &gt; 0) {
       garrow_stream_decoder_consume_buffer(decoder, GARROW_BUFFER(buffer), <span class="caps">NULL</span>);
     }&nbsp;g_object_unref(buffer);</p>
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         <p>Available since: 18.0.0</p>


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       </h4>

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         <div class="returns">
           <div class="arg-description">
             <p><em>Type:</em>&nbsp;<code>gsize</code></p>
             <p><p>The number of bytes needed to advance the state of
   the&nbsp;decoder.</p></p>
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	<div class="section namespace">
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	<p>API Version: 1.0</p>

	<p>Library Version: 22.0.0</p>

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	<div class="section">
	<h5>Type</h5>
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	<a href="class.StreamDecoder.html">StreamDecoder</a>
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	<section id="main" class="content">
	<header>
	<h3>Method</h3>
	<h1><a href="index.html">Arrow</a><span class="sep"></span><a href="class.StreamDecoder.html">StreamDecoder</a><span class="sep"></span>get_next_required_size</h1>
	</header>

	<section>
	<div class="docblock">
	<p><span class="emblem available">since: 18.0.0</span></p>
	</div>

	<div class="declaration toggle-wrapper">
	<h4 style="display:flex;" id="declaration">
	Declaration
	<a class="anchor" href="#declaration"></a>

	<a class="srclink" title="go to source location" href="https://github.com/apache/arrow/blob/main/c_glib/arrow-glib/decoder.h#L94">[src]</a>

	</h4>

	<div class="docblock c-decl">
	<pre><code><div class="highlight"><pre><span></span><span class="n">gsize</span>
	<span class="n">garrow_stream_decoder_get_next_required_size</span><span class="w"> </span><span class="p">(</span>
	<span class="w"> </span><span class="n">GArrowStreamDecoder</span><span class="o">*</span><span class="w"> </span><span class="n">decoder</span>
	<span class="p">)</span>
	</pre></div>
	</code></pre>
	</div>
	</div>

	<div class="description toggle-wrapper">
	<h4 style="display:flex;" id="description">
	Description
	<a class="anchor" href="#description"></a>

	<a class="srclink" title="go to source location" href="https://github.com/apache/arrow/blob/main/c_glib/arrow-glib/decoder.cpp#L509">[src]</a>

	</h4>

	<div class="docblock">
	<p>This method is provided for users who want to optimize performance.
	Normal users don’t need to use this method.</p>
	<p>Here is an example usage for normal users:</p>
	<div class="codehilite"><pre><span></span><code>garrow_stream_decoder_consume_buffer(decoder, buffer1);
	garrow_stream_decoder_consume_buffer(decoder, buffer2);
	garrow_stream_decoder_consume_buffer(decoder, buffer3);
	</code></pre></div>

	<p>Decoder has internal buffer. If consumed data isn’t enough to
	advance the state of the decoder, consumed data is buffered to
	the internal buffer. It causes performance overhead.</p>
	<p>If you pass <code>garrow_stream_decoer_get_next_required_size()</code> size data
	to each
	garrow_stream_decoder_consume_bytes()/garrow_stream_decoder_consume_buffer()
	call, the decoder doesn’t use its internal buffer. It improves performance.</p>
	<p>Here is an example usage to avoid using internal buffer:</p>
	<div class="codehilite"><pre><span></span><code>buffer1 = get_data(garrow_stream_decoder_get_next_required_size(decoder));
	garrow_stream_decoder_consume_buffer(buffer1);
	buffer2 = get_data(garrow_stream_decoder_get_next_required_size(decoder));
	garrow_stream_decoder_consume_buffer(buffer2);
	</code></pre></div>

	<p>Users can use this method to avoid creating small chunks. Record
	batch data must be contiguous data. If users pass small chunks to
	the decoder, the decoder needs concatenate small chunks
	internally. It causes performance overhead.</p>
	<p>Here is an example usage to reduce small chunks:</p>
	<div class="codehilite"><pre><span></span><code>GArrowResizablBuffer *buffer = garrow_resizable_buffer_new(1024, NULL);
	while ((small_chunk = get_data(&small_chunk_size))) {
	size_t current_buffer_size = garrow_buffer_get_size(GARROW_BUFFER(buffer));
	garrow_resizable_buffer_resize(buffer, current_buffer_size + small_chunk_size,
	</code></pre></div>

	<p><span class="caps">NULL</span>);
	garrow_mutable_buffer_set_data(GARROW_MUTABLE_BUFFER(buffer),
	current_buffer_size,
	small_chunk,
	small_chunk_size,
	<span class="caps">NULL</span>);
	if (garrow_buffer_get_size(GARROW_BUFFER(buffer)) <
	garrow_stream_decoder_get_next_required_size(decoder)) {
	continue;
	}
	garrow_stream_decoder_consume_buffer(decoder, GARROW_BUFFER(buffer), <span class="caps">NULL</span>);
	g_object_unref(buffer);
	buffer = garrow_resizable_buffer_new(1024, <span class="caps">NULL</span>);
	}
	if (garrow_buffer_get_size(GARROW_BUFFER(buffer)) > 0) {
	garrow_stream_decoder_consume_buffer(decoder, GARROW_BUFFER(buffer), <span class="caps">NULL</span>);
	} g_object_unref(buffer);</p>
	</div>

	<div class="docblock">

	<p>Available since: 18.0.0</p>




	</div>


	</div>




	<div class="return-value toggle-wrapper">
	<h4 id="return-value">
	Return value
	<a href="#return-value" class="anchor"></a>
	</h4>

	<div class="docblock">
	<div class="returns">
	<div class="arg-description">
	<p><em>Type:</em> <code>gsize</code></p>
	<p><p>The number of bytes needed to advance the state of
	the decoder.</p></p>
	</div>
	<div>
	<table>






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