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| <a href="#GstAdapter.synopsis" class="shortcut">Top</a> |
| | |
| <a href="#GstAdapter.description" class="shortcut">Description</a> |
| | |
| <a href="#GstAdapter.object-hierarchy" class="shortcut">Object Hierarchy</a> |
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| <div class="refentry"> |
| <a name="GstAdapter"></a><div class="titlepage"></div> |
| <div class="refnamediv"><table width="100%"><tr> |
| <td valign="top"> |
| <h2><span class="refentrytitle"><a name="GstAdapter.top_of_page"></a>GstAdapter</span></h2> |
| <p>GstAdapter — adapts incoming data on a sink pad into chunks of N bytes</p> |
| </td> |
| <td valign="top" align="right"></td> |
| </tr></table></div> |
| <div class="refsynopsisdiv"> |
| <a name="GstAdapter.synopsis"></a><h2>Synopsis</h2> |
| <pre class="synopsis"> |
| #include <gst/base/gstadapter.h> |
| |
| <a class="link" href="GstAdapter.html#GstAdapter-struct" title="GstAdapter">GstAdapter</a>; |
| <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="returnvalue">GstAdapter</span></a> * <a class="link" href="GstAdapter.html#gst-adapter-new" title="gst_adapter_new ()">gst_adapter_new</a> (<em class="parameter"><code><span class="type">void</span></code></em>); |
| <span class="returnvalue">void</span> <a class="link" href="GstAdapter.html#gst-adapter-clear" title="gst_adapter_clear ()">gst_adapter_clear</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>); |
| <span class="returnvalue">void</span> <a class="link" href="GstAdapter.html#gst-adapter-push" title="gst_adapter_push ()">gst_adapter_push</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="type">GstBuffer</span></a> *buf</code></em>); |
| <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gconstpointer"><span class="returnvalue">gconstpointer</span></a> <a class="link" href="GstAdapter.html#gst-adapter-map" title="gst_adapter_map ()">gst_adapter_map</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>); |
| <span class="returnvalue">void</span> <a class="link" href="GstAdapter.html#gst-adapter-unmap" title="gst_adapter_unmap ()">gst_adapter_unmap</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>); |
| <span class="returnvalue">void</span> <a class="link" href="GstAdapter.html#gst-adapter-copy" title="gst_adapter_copy ()">gst_adapter_copy</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> dest</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> offset</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>); |
| <span class="returnvalue">void</span> <a class="link" href="GstAdapter.html#gst-adapter-flush" title="gst_adapter_flush ()">gst_adapter_flush</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> flush</code></em>); |
| <span class="returnvalue">gsize</span> <a class="link" href="GstAdapter.html#gst-adapter-available" title="gst_adapter_available ()">gst_adapter_available</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>); |
| <span class="returnvalue">gsize</span> <a class="link" href="GstAdapter.html#gst-adapter-available-fast" title="gst_adapter_available_fast ()">gst_adapter_available_fast</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>); |
| <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> <a class="link" href="GstAdapter.html#gst-adapter-take" title="gst_adapter_take ()">gst_adapter_take</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> nbytes</code></em>); |
| <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="returnvalue">GstBuffer</span></a> * <a class="link" href="GstAdapter.html#gst-adapter-take-buffer" title="gst_adapter_take_buffer ()">gst_adapter_take_buffer</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> nbytes</code></em>); |
| <a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GList"><span class="returnvalue">GList</span></a> * <a class="link" href="GstAdapter.html#gst-adapter-take-list" title="gst_adapter_take_list ()">gst_adapter_take_list</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> nbytes</code></em>); |
| <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="returnvalue">GstClockTime</span></a> <a class="link" href="GstAdapter.html#gst-adapter-prev-pts" title="gst_adapter_prev_pts ()">gst_adapter_prev_pts</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint64</span> *distance</code></em>); |
| <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="returnvalue">GstClockTime</span></a> <a class="link" href="GstAdapter.html#gst-adapter-prev-dts" title="gst_adapter_prev_dts ()">gst_adapter_prev_dts</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint64</span> *distance</code></em>); |
| <span class="returnvalue">gsize</span> <a class="link" href="GstAdapter.html#gst-adapter-masked-scan-uint32" title="gst_adapter_masked_scan_uint32 ()">gst_adapter_masked_scan_uint32</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> mask</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> pattern</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> offset</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>); |
| <span class="returnvalue">gsize</span> <a class="link" href="GstAdapter.html#gst-adapter-masked-scan-uint32-peek" title="gst_adapter_masked_scan_uint32_peek ()">gst_adapter_masked_scan_uint32_peek</a> (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> mask</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> pattern</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> offset</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> *value</code></em>); |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="GstAdapter.object-hierarchy"></a><h2>Object Hierarchy</h2> |
| <pre class="synopsis"> |
| <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a> |
| +----GstAdapter |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="GstAdapter.description"></a><h2>Description</h2> |
| <p> |
| This class is for elements that receive buffers in an undesired size. |
| While for example raw video contains one image per buffer, the same is not |
| true for a lot of other formats, especially those that come directly from |
| a file. So if you have undefined buffer sizes and require a specific size, |
| this object is for you. |
| </p> |
| <p> |
| An adapter is created with <a class="link" href="GstAdapter.html#gst-adapter-new" title="gst_adapter_new ()"><code class="function">gst_adapter_new()</code></a>. It can be freed again with |
| <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#g-object-unref"><code class="function">g_object_unref()</code></a>. |
| </p> |
| <p> |
| The theory of operation is like this: All buffers received are put |
| into the adapter using <a class="link" href="GstAdapter.html#gst-adapter-push" title="gst_adapter_push ()"><code class="function">gst_adapter_push()</code></a> and the data is then read back |
| in chunks of the desired size using <a class="link" href="GstAdapter.html#gst-adapter-map" title="gst_adapter_map ()"><code class="function">gst_adapter_map()</code></a>/<a class="link" href="GstAdapter.html#gst-adapter-unmap" title="gst_adapter_unmap ()"><code class="function">gst_adapter_unmap()</code></a> |
| and/or <a class="link" href="GstAdapter.html#gst-adapter-copy" title="gst_adapter_copy ()"><code class="function">gst_adapter_copy()</code></a>. After the data has been processed, it is freed |
| using <a class="link" href="GstAdapter.html#gst-adapter-unmap" title="gst_adapter_unmap ()"><code class="function">gst_adapter_unmap()</code></a>. |
| </p> |
| <p> |
| Other methods such as <a class="link" href="GstAdapter.html#gst-adapter-take" title="gst_adapter_take ()"><code class="function">gst_adapter_take()</code></a> and <a class="link" href="GstAdapter.html#gst-adapter-take-buffer" title="gst_adapter_take_buffer ()"><code class="function">gst_adapter_take_buffer()</code></a> |
| combine <a class="link" href="GstAdapter.html#gst-adapter-map" title="gst_adapter_map ()"><code class="function">gst_adapter_map()</code></a> and <a class="link" href="GstAdapter.html#gst-adapter-unmap" title="gst_adapter_unmap ()"><code class="function">gst_adapter_unmap()</code></a> in one method and are |
| potentially more convenient for some use cases. |
| </p> |
| <p> |
| For example, a sink pad's chain function that needs to pass data to a library |
| in 512-byte chunks could be implemented like this: |
| </p> |
| <div class="informalexample"> |
| <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> |
| <tbody> |
| <tr> |
| <td class="listing_lines" align="right"><pre>1 |
| 2 |
| 3 |
| 4 |
| 5 |
| 6 |
| 7 |
| 8 |
| 9 |
| 10 |
| 11 |
| 12 |
| 13 |
| 14 |
| 15 |
| 16 |
| 17 |
| 18 |
| 19 |
| 20 |
| 21 |
| 22 |
| 23 |
| 24</pre></td> |
| <td class="listing_code"><pre class="programlisting"><span class="gtkdoc kwb">static</span> GstFlowReturn |
| <span class="function">sink_pad_chain</span> <span class="gtkdoc opt">(</span>GstPad <span class="gtkdoc opt">*</span>pad<span class="gtkdoc opt">,</span> GstObject <span class="gtkdoc opt">*</span>parent<span class="gtkdoc opt">,</span> GstBuffer <span class="gtkdoc opt">*</span>buffer<span class="gtkdoc opt">)</span> |
| <span class="gtkdoc opt">{</span> |
| MyElement <span class="gtkdoc opt">*</span><span class="keyword">this</span><span class="gtkdoc opt">;</span> |
| GstAdapter <span class="gtkdoc opt">*</span>adapter<span class="gtkdoc opt">;</span> |
| GstFlowReturn ret <span class="gtkdoc opt">=</span> GST_FLOW_OK<span class="gtkdoc opt">;</span> |
| |
| <span class="keyword">this</span> <span class="gtkdoc opt">=</span> <span class="function">MY_ELEMENT</span> <span class="gtkdoc opt">(</span>parent<span class="gtkdoc opt">);</span> |
| |
| adapter <span class="gtkdoc opt">=</span> <span class="keyword">this</span><span class="gtkdoc opt">-></span>adapter<span class="gtkdoc opt">;</span> |
| |
| <span class="gtkdoc slc">// put buffer into adapter</span> |
| <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstAdapter.html#gst-adapter-push">gst_adapter_push</a></span> <span class="gtkdoc opt">(</span>adapter<span class="gtkdoc opt">,</span> buffer<span class="gtkdoc opt">);</span> |
| |
| <span class="gtkdoc slc">// while we can read out 512 bytes, process them</span> |
| <span class="keyword">while</span> <span class="gtkdoc opt">(</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstAdapter.html#gst-adapter-available">gst_adapter_available</a></span> <span class="gtkdoc opt">(</span>adapter<span class="gtkdoc opt">) >=</span> <span class="number">512</span> <span class="gtkdoc opt">&&</span> ret <span class="gtkdoc opt">==</span> GST_FLOW_OK<span class="gtkdoc opt">) {</span> |
| <span class="gtkdoc kwb">const</span> guint8 <span class="gtkdoc opt">*</span>data <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstAdapter.html#gst-adapter-map">gst_adapter_map</a></span> <span class="gtkdoc opt">(</span>adapter<span class="gtkdoc opt">,</span> <span class="number">512</span><span class="gtkdoc opt">);</span> |
| <span class="gtkdoc slc">// use flowreturn as an error value</span> |
| ret <span class="gtkdoc opt">=</span> <span class="function">my_library_foo</span> <span class="gtkdoc opt">(</span>data<span class="gtkdoc opt">);</span> |
| <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstAdapter.html#gst-adapter-unmap">gst_adapter_unmap</a></span> <span class="gtkdoc opt">(</span>adapter<span class="gtkdoc opt">);</span> |
| <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstAdapter.html#gst-adapter-flush">gst_adapter_flush</a></span> <span class="gtkdoc opt">(</span>adapter<span class="gtkdoc opt">,</span> <span class="number">512</span><span class="gtkdoc opt">);</span> |
| <span class="gtkdoc opt">}</span> |
| <span class="keyword">return</span> ret<span class="gtkdoc opt">;</span> |
| <span class="gtkdoc opt">}</span></pre></td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| |
| <p> |
| </p> |
| <p> |
| For another example, a simple element inside GStreamer that uses GstAdapter |
| is the libvisual element. |
| </p> |
| <p> |
| An element using GstAdapter in its sink pad chain function should ensure that |
| when the FLUSH_STOP event is received, that any queued data is cleared using |
| <a class="link" href="GstAdapter.html#gst-adapter-clear" title="gst_adapter_clear ()"><code class="function">gst_adapter_clear()</code></a>. Data should also be cleared or processed on EOS and |
| when changing state from <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#GST-STATE-PAUSED:CAPS"><span class="type">GST_STATE_PAUSED</span></a> to <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#GST-STATE-READY:CAPS"><span class="type">GST_STATE_READY</span></a>. |
| </p> |
| <p> |
| Also check the GST_BUFFER_FLAG_DISCONT flag on the buffer. Some elements might |
| need to clear the adapter after a discontinuity. |
| </p> |
| <p> |
| The adapter will keep track of the timestamps of the buffers |
| that were pushed. The last seen timestamp before the current position |
| can be queried with <code class="function">gst_adapter_prev_timestamp()</code>. This function can |
| optionally return the amount of bytes between the start of the buffer that |
| carried the timestamp and the current adapter position. The distance is |
| useful when dealing with, for example, raw audio samples because it allows |
| you to calculate the timestamp of the current adapter position by using the |
| last seen timestamp and the amount of bytes since. |
| </p> |
| <p> |
| A last thing to note is that while GstAdapter is pretty optimized, |
| merging buffers still might be an operation that requires a <code class="function">malloc()</code> and |
| <code class="function">memcpy()</code> operation, and these operations are not the fastest. Because of |
| this, some functions like <a class="link" href="GstAdapter.html#gst-adapter-available-fast" title="gst_adapter_available_fast ()"><code class="function">gst_adapter_available_fast()</code></a> are provided to help |
| speed up such cases should you want to. To avoid repeated memory allocations, |
| <a class="link" href="GstAdapter.html#gst-adapter-copy" title="gst_adapter_copy ()"><code class="function">gst_adapter_copy()</code></a> can be used to copy data into a (statically allocated) |
| user provided buffer. |
| </p> |
| <p> |
| GstAdapter is not MT safe. All operations on an adapter must be serialized by |
| the caller. This is not normally a problem, however, as the normal use case |
| of GstAdapter is inside one pad's chain function, in which case access is |
| serialized via the pad's STREAM_LOCK. |
| </p> |
| <p> |
| Note that <a class="link" href="GstAdapter.html#gst-adapter-push" title="gst_adapter_push ()"><code class="function">gst_adapter_push()</code></a> takes ownership of the buffer passed. Use |
| <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#gst-buffer-ref"><code class="function">gst_buffer_ref()</code></a> before pushing it into the adapter if you still want to |
| access the buffer later. The adapter will never modify the data in the |
| buffer pushed in it. |
| </p> |
| <p> |
| Last reviewed on 2009-05-13 (0.10.24). |
| </p> |
| </div> |
| <div class="refsect1"> |
| <a name="GstAdapter.details"></a><h2>Details</h2> |
| <div class="refsect2"> |
| <a name="GstAdapter-struct"></a><h3>GstAdapter</h3> |
| <pre class="programlisting">typedef struct _GstAdapter GstAdapter;</pre> |
| <p> |
| The opaque <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> data structure. |
| </p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-new"></a><h3>gst_adapter_new ()</h3> |
| <pre class="programlisting"><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="returnvalue">GstAdapter</span></a> * gst_adapter_new (<em class="parameter"><code><span class="type">void</span></code></em>);</pre> |
| <p> |
| Creates a new <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a>. Free with <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#g-object-unref"><code class="function">g_object_unref()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody><tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>a new <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a>. <span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span> |
| </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-clear"></a><h3>gst_adapter_clear ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> gst_adapter_clear (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>);</pre> |
| <p> |
| Removes all buffers from <em class="parameter"><code>adapter</code></em>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody><tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-push"></a><h3>gst_adapter_push ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> gst_adapter_push (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="type">GstBuffer</span></a> *buf</code></em>);</pre> |
| <p> |
| Adds the data from <em class="parameter"><code>buf</code></em> to the data stored inside <em class="parameter"><code>adapter</code></em> and takes |
| ownership of the buffer. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>buf</code></em> :</span></p></td> |
| <td>a <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="type">GstBuffer</span></a> to add to queue in the adapter. <span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-map"></a><h3>gst_adapter_map ()</h3> |
| <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gconstpointer"><span class="returnvalue">gconstpointer</span></a> gst_adapter_map (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>);</pre> |
| <p> |
| Gets the first <em class="parameter"><code>size</code></em> bytes stored in the <em class="parameter"><code>adapter</code></em>. The returned pointer is |
| valid until the next function is called on the adapter. |
| </p> |
| <p> |
| Note that setting the returned pointer as the data of a <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="type">GstBuffer</span></a> is |
| incorrect for general-purpose plugins. The reason is that if a downstream |
| element stores the buffer so that it has access to it outside of the bounds |
| of its chain function, the buffer will have an invalid data pointer after |
| your element flushes the bytes. In that case you should use |
| <a class="link" href="GstAdapter.html#gst-adapter-take" title="gst_adapter_take ()"><code class="function">gst_adapter_take()</code></a>, which returns a freshly-allocated buffer that you can set |
| as <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="type">GstBuffer</span></a> memory or the potentially more performant |
| <a class="link" href="GstAdapter.html#gst-adapter-take-buffer" title="gst_adapter_take_buffer ()"><code class="function">gst_adapter_take_buffer()</code></a>. |
| </p> |
| <p> |
| Returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><span class="type">NULL</span></a> if <em class="parameter"><code>size</code></em> bytes are not available. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>size</code></em> :</span></p></td> |
| <td>the number of bytes to map/peek</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>a pointer to the first <em class="parameter"><code>size</code></em> bytes of data, or NULL. <span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=size][<acronym title="Generics and defining elements of containers and arrays."><span class="acronym">element-type</span></acronym> guint8]</span> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-unmap"></a><h3>gst_adapter_unmap ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> gst_adapter_unmap (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>);</pre> |
| <p> |
| Releases the memory obtained with the last <a class="link" href="GstAdapter.html#gst-adapter-map" title="gst_adapter_map ()"><code class="function">gst_adapter_map()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody><tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-copy"></a><h3>gst_adapter_copy ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> gst_adapter_copy (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> dest</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> offset</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>);</pre> |
| <p> |
| Copies <em class="parameter"><code>size</code></em> bytes of data starting at <em class="parameter"><code>offset</code></em> out of the buffers |
| contained in <em class="parameter"><code>GstAdapter</code></em> into an array <em class="parameter"><code>dest</code></em> provided by the caller. |
| </p> |
| <p> |
| The array <em class="parameter"><code>dest</code></em> should be large enough to contain <em class="parameter"><code>size</code></em> bytes. |
| The user should check that the adapter has (<em class="parameter"><code>offset</code></em> + <em class="parameter"><code>size</code></em>) bytes |
| available before calling this function. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>dest</code></em> :</span></p></td> |
| <td>the memory to copy into. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym> caller-allocates][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=size][<acronym title="Generics and defining elements of containers and arrays."><span class="acronym">element-type</span></acronym> guint8]</span> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>offset</code></em> :</span></p></td> |
| <td>the bytes offset in the adapter to start from</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>size</code></em> :</span></p></td> |
| <td>the number of bytes to copy</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-flush"></a><h3>gst_adapter_flush ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> gst_adapter_flush (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> flush</code></em>);</pre> |
| <p> |
| Flushes the first <em class="parameter"><code>flush</code></em> bytes in the <em class="parameter"><code>adapter</code></em>. The caller must ensure that |
| at least this many bytes are available. |
| </p> |
| <p> |
| See also: <a class="link" href="GstAdapter.html#gst-adapter-map" title="gst_adapter_map ()"><code class="function">gst_adapter_map()</code></a>, <a class="link" href="GstAdapter.html#gst-adapter-unmap" title="gst_adapter_unmap ()"><code class="function">gst_adapter_unmap()</code></a> |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>flush</code></em> :</span></p></td> |
| <td>the number of bytes to flush</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-available"></a><h3>gst_adapter_available ()</h3> |
| <pre class="programlisting"><span class="returnvalue">gsize</span> gst_adapter_available (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>);</pre> |
| <p> |
| Gets the maximum amount of bytes available, that is it returns the maximum |
| value that can be supplied to <a class="link" href="GstAdapter.html#gst-adapter-map" title="gst_adapter_map ()"><code class="function">gst_adapter_map()</code></a> without that function |
| returning NULL. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>number of bytes available in <em class="parameter"><code>adapter</code></em> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-available-fast"></a><h3>gst_adapter_available_fast ()</h3> |
| <pre class="programlisting"><span class="returnvalue">gsize</span> gst_adapter_available_fast (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>);</pre> |
| <p> |
| Gets the maximum number of bytes that are immediately available without |
| requiring any expensive operations (like copying the data into a |
| temporary buffer). |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>number of bytes that are available in <em class="parameter"><code>adapter</code></em> without expensive |
| operations</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-take"></a><h3>gst_adapter_take ()</h3> |
| <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> gst_adapter_take (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> nbytes</code></em>);</pre> |
| <p> |
| Returns a freshly allocated buffer containing the first <em class="parameter"><code>nbytes</code></em> bytes of the |
| <em class="parameter"><code>adapter</code></em>. The returned bytes will be flushed from the adapter. |
| </p> |
| <p> |
| Caller owns returned value. g_free after usage. |
| </p> |
| <p> |
| Free-function: g_free |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>nbytes</code></em> :</span></p></td> |
| <td>the number of bytes to take</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>oven-fresh hot data, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><span class="type">NULL</span></a> if <em class="parameter"><code>nbytes</code></em> bytes are not available. <span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=nbytes][<acronym title="Generics and defining elements of containers and arrays."><span class="acronym">element-type</span></acronym> guint8]</span> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-take-buffer"></a><h3>gst_adapter_take_buffer ()</h3> |
| <pre class="programlisting"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="returnvalue">GstBuffer</span></a> * gst_adapter_take_buffer (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> nbytes</code></em>);</pre> |
| <p> |
| Returns a <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="type">GstBuffer</span></a> containing the first <em class="parameter"><code>nbytes</code></em> bytes of the |
| <em class="parameter"><code>adapter</code></em>. The returned bytes will be flushed from the adapter. |
| This function is potentially more performant than <a class="link" href="GstAdapter.html#gst-adapter-take" title="gst_adapter_take ()"><code class="function">gst_adapter_take()</code></a> |
| since it can reuse the memory in pushed buffers by subbuffering |
| or merging. |
| </p> |
| <p> |
| Note that no assumptions should be made as to whether certain buffer |
| flags such as the DISCONT flag are set on the returned buffer, or not. |
| The caller needs to explicitly set or unset flags that should be set or |
| unset. |
| </p> |
| <p> |
| Caller owns a reference to the returned buffer. <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#gst-buffer-unref"><code class="function">gst_buffer_unref()</code></a> after |
| usage. |
| </p> |
| <p> |
| Free-function: gst_buffer_unref |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>nbytes</code></em> :</span></p></td> |
| <td>the number of bytes to take</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>a <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#GstBuffer"><span class="type">GstBuffer</span></a> containing the first <em class="parameter"><code>nbytes</code></em> of |
| the adapter, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><span class="type">NULL</span></a> if <em class="parameter"><code>nbytes</code></em> bytes are not available. |
| <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#gst-buffer-unref"><code class="function">gst_buffer_unref()</code></a> when no longer needed. <span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-take-list"></a><h3>gst_adapter_take_list ()</h3> |
| <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GList"><span class="returnvalue">GList</span></a> * gst_adapter_take_list (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> nbytes</code></em>);</pre> |
| <p> |
| Returns a <a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GList"><span class="type">GList</span></a> of buffers containing the first <em class="parameter"><code>nbytes</code></em> bytes of the |
| <em class="parameter"><code>adapter</code></em>. The returned bytes will be flushed from the adapter. |
| When the caller can deal with individual buffers, this function is more |
| performant because no memory should be copied. |
| </p> |
| <p> |
| Caller owns returned list and contained buffers. <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBuffer.html#gst-buffer-unref"><code class="function">gst_buffer_unref()</code></a> each |
| buffer in the list before freeing the list after usage. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>nbytes</code></em> :</span></p></td> |
| <td>the number of bytes to take</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>a <a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GList"><span class="type">GList</span></a> of buffers |
| containing the first <em class="parameter"><code>nbytes</code></em> of the adapter, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><span class="type">NULL</span></a> if <em class="parameter"><code>nbytes</code></em> bytes |
| are not available. <span class="annotation">[<acronym title="Generics and defining elements of containers and arrays."><span class="acronym">element-type</span></acronym> Gst.Buffer][<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-prev-pts"></a><h3>gst_adapter_prev_pts ()</h3> |
| <pre class="programlisting"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="returnvalue">GstClockTime</span></a> gst_adapter_prev_pts (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint64</span> *distance</code></em>);</pre> |
| <p> |
| Get the pts that was before the current byte in the adapter. When |
| <em class="parameter"><code>distance</code></em> is given, the amount of bytes between the pts and the current |
| position is returned. |
| </p> |
| <p> |
| The pts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when |
| the adapter is first created or when it is cleared. This also means that before |
| the first byte with a pts is removed from the adapter, the pts |
| and distance returned are GST_CLOCK_TIME_NONE and 0 respectively. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>distance</code></em> :</span></p></td> |
| <td>pointer to location for distance, or NULL. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is ok, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>The previously seen pts.</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-prev-dts"></a><h3>gst_adapter_prev_dts ()</h3> |
| <pre class="programlisting"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="returnvalue">GstClockTime</span></a> gst_adapter_prev_dts (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint64</span> *distance</code></em>);</pre> |
| <p> |
| Get the dts that was before the current byte in the adapter. When |
| <em class="parameter"><code>distance</code></em> is given, the amount of bytes between the dts and the current |
| position is returned. |
| </p> |
| <p> |
| The dts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when |
| the adapter is first created or when it is cleared. This also means that before |
| the first byte with a dts is removed from the adapter, the dts |
| and distance returned are GST_CLOCK_TIME_NONE and 0 respectively. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>distance</code></em> :</span></p></td> |
| <td>pointer to location for distance, or NULL. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is ok, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>The previously seen dts.</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-masked-scan-uint32"></a><h3>gst_adapter_masked_scan_uint32 ()</h3> |
| <pre class="programlisting"><span class="returnvalue">gsize</span> gst_adapter_masked_scan_uint32 (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> mask</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> pattern</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> offset</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>);</pre> |
| <p> |
| Scan for pattern <em class="parameter"><code>pattern</code></em> with applied mask <em class="parameter"><code>mask</code></em> in the adapter data, |
| starting from offset <em class="parameter"><code>offset</code></em>. |
| </p> |
| <p> |
| The bytes in <em class="parameter"><code>pattern</code></em> and <em class="parameter"><code>mask</code></em> are interpreted left-to-right, regardless |
| of endianness. All four bytes of the pattern must be present in the |
| adapter for it to match, even if the first or last bytes are masked out. |
| </p> |
| <p> |
| It is an error to call this function without making sure that there is |
| enough data (offset+size bytes) in the adapter. |
| </p> |
| <p> |
| This function calls <a class="link" href="GstAdapter.html#gst-adapter-masked-scan-uint32-peek" title="gst_adapter_masked_scan_uint32_peek ()"><code class="function">gst_adapter_masked_scan_uint32_peek()</code></a> passing NULL |
| for value. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>mask</code></em> :</span></p></td> |
| <td>mask to apply to data before matching against <em class="parameter"><code>pattern</code></em> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>pattern</code></em> :</span></p></td> |
| <td>pattern to match (after mask is applied)</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>offset</code></em> :</span></p></td> |
| <td>offset into the adapter data from which to start scanning, returns |
| the last scanned position.</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>size</code></em> :</span></p></td> |
| <td>number of bytes to scan from offset</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>offset of the first match, or -1 if no match was found. |
| Example: |
| <pre class="programlisting"> |
| // Assume the adapter contains 0x00 0x01 0x02 ... 0xfe 0xff |
| gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 0, 256); |
| // -> returns 0 |
| gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 1, 255); |
| // -> returns -1 |
| gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x01020304, 1, 255); |
| // -> returns 1 |
| gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0001, 0, 256); |
| // -> returns -1 |
| gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0203, 0, 256); |
| // -> returns 0 |
| gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 256); |
| // -> returns 2 |
| gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 4); |
| // -> returns -1 |
| </pre> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-adapter-masked-scan-uint32-peek"></a><h3>gst_adapter_masked_scan_uint32_peek ()</h3> |
| <pre class="programlisting"><span class="returnvalue">gsize</span> gst_adapter_masked_scan_uint32_peek (<em class="parameter"><code><a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> *adapter</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> mask</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> pattern</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> offset</code></em>, |
| <em class="parameter"><code><span class="type">gsize</span> size</code></em>, |
| <em class="parameter"><code><span class="type">guint32</span> *value</code></em>);</pre> |
| <p> |
| Scan for pattern <em class="parameter"><code>pattern</code></em> with applied mask <em class="parameter"><code>mask</code></em> in the adapter data, |
| starting from offset <em class="parameter"><code>offset</code></em>. If a match is found, the value that matched |
| is returned through <em class="parameter"><code>value</code></em>, otherwise <em class="parameter"><code>value</code></em> is left untouched. |
| </p> |
| <p> |
| The bytes in <em class="parameter"><code>pattern</code></em> and <em class="parameter"><code>mask</code></em> are interpreted left-to-right, regardless |
| of endianness. All four bytes of the pattern must be present in the |
| adapter for it to match, even if the first or last bytes are masked out. |
| </p> |
| <p> |
| It is an error to call this function without making sure that there is |
| enough data (offset+size bytes) in the adapter. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>adapter</code></em> :</span></p></td> |
| <td>a <a class="link" href="GstAdapter.html" title="GstAdapter"><span class="type">GstAdapter</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>mask</code></em> :</span></p></td> |
| <td>mask to apply to data before matching against <em class="parameter"><code>pattern</code></em> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>pattern</code></em> :</span></p></td> |
| <td>pattern to match (after mask is applied)</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>offset</code></em> :</span></p></td> |
| <td>offset into the adapter data from which to start scanning, returns |
| the last scanned position.</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>size</code></em> :</span></p></td> |
| <td>number of bytes to scan from offset</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>value</code></em> :</span></p></td> |
| <td>pointer to uint32 to return matching data</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>offset of the first match, or -1 if no match was found.</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| </div> |
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