file: expose seek function in public API

include/osmosdr/source.h

@@ -57,6 +57,15 @@ public:
    */
   virtual size_t get_num_channels( void ) = 0;
 
+  /*!
+   * \brief seek file to \p seek_point relative to \p whence
+   *
+   * \param seek_point	sample offset in file
+   * \param whence	one of SEEK_SET, SEEK_CUR, SEEK_END (man fseek)
+   * \return true on success
+   */
+  virtual bool seek( long seek_point, int whence, size_t chan = 0 ) = 0;
+
   /*!
    * Get the possible sample rates for the underlying radio hardware.
    * \return a range of rates in Sps

lib/file/file_source_c.cc

@@ -26,7 +26,6 @@
 #include <boost/format.hpp>
 
 #include <gnuradio/io_signature.h>
-#include <gnuradio/blocks/file_source.h>
 
 #include "file_source_c.h"
 
@@ -78,18 +77,17 @@ file_source_c::file_source_c(const std::string &args) :
 
   _file_rate = _rate;
 
-  gr::blocks::file_source::sptr src = \
-      gr::blocks::file_source::make( sizeof(gr_complex),
-                                     filename.c_str(),
-                                     repeat );
+  _source = gr::blocks::file_source::make( sizeof(gr_complex),
+                                           filename.c_str(),
+                                           repeat );
 
   _throttle = gr::blocks::throttle::make( sizeof(gr_complex), _file_rate );
 
   if (throttle) {
-    connect( src, 0, _throttle, 0 );
+    connect( _source, 0, _throttle, 0 );
     connect( _throttle, 0, self(), 0 );
   } else {
-    connect( src, 0, self(), 0 );
+    connect( _source, 0, self(), 0 );
   }
 }
 
@@ -122,6 +120,11 @@ size_t file_source_c::get_num_channels( void )
   return 1;
 }
 
+bool file_source_c::seek( long seek_point, int whence , size_t chan )
+{
+    return _source->seek( seek_point, whence );
+}
+
 osmosdr::meta_range_t file_source_c::get_sample_rates( void )
 {
   osmosdr::meta_range_t range;

lib/file/file_source_c.h

@@ -21,6 +21,7 @@
 #define FILE_SOURCE_C_H
 
 #include <gnuradio/hier_block2.h>
+#include <gnuradio/blocks/file_source.h>
 #include <gnuradio/blocks/throttle.h>
 
 #include "source_iface.h"
@@ -49,6 +50,8 @@ public:
 
   size_t get_num_channels( void );
 
+  bool seek( long seek_point, int whence, size_t chan );
+
   osmosdr::meta_range_t get_sample_rates( void );
   double set_sample_rate( double rate );
   double get_sample_rate( void );
@@ -72,6 +75,7 @@ public:
   std::string get_antenna( size_t chan = 0 );
 
 private:
+  gr::blocks::file_source::sptr _source;
   gr::blocks::throttle::sptr _throttle;
   double _file_rate;
   double _freq, _rate;

lib/source_iface.h

@@ -37,6 +37,15 @@ public:
    */
   virtual size_t get_num_channels( void ) = 0;
 
+  /*!
+   * \brief seek file to \p seek_point relative to \p whence
+   *
+   * \param seek_point	sample offset in file
+   * \param whence	one of SEEK_SET, SEEK_CUR, SEEK_END (man fseek)
+   * \return true on success
+   */
+  virtual bool seek( long seek_point, int whence, size_t chan = 0 ) { return false; }
+
   /*!
    * Get the possible sample rates for the underlying radio hardware.
    * \return a range of rates in Sps

lib/source_impl.cc

@@ -376,6 +376,17 @@ size_t source_impl::get_num_channels()
   return channels;
 }
 
+bool source_impl::seek( long seek_point, int whence, size_t chan )
+{
+  size_t channel = 0;
+  BOOST_FOREACH( source_iface *dev, _devs )
+    for (size_t dev_chan = 0; dev_chan < dev->get_num_channels(); dev_chan++)
+      if ( chan == channel++ )
+        return dev->seek( seek_point, whence, dev_chan );
+
+  return false;
+}
+
 #define NO_DEVICES_MSG  "FATAL: No device(s) available to work with."
 
 osmosdr::meta_range_t source_impl::get_sample_rates()

lib/source_impl.h

@@ -38,6 +38,8 @@ public:
 
   size_t get_num_channels( void );
 
+  bool seek( long seek_point, int whence, size_t chan );
+
   osmosdr::meta_range_t get_sample_rates( void );
   double set_sample_rate( double rate );
   double get_sample_rate( void );