rtl: fix large output buffers handling

When size of output buffer was larger than size of input buffer,
uderflow occured because no check on number of avalilable data was done.

This also improves buffer filling for large output buffers, fill output
until anny input is available.

1 files changed, 17 insertions, 23 deletions

diff --git a/lib/rtl/rtl_source_c.cc b/lib/rtl/rtl_source_c.cc
index 3c29e42..ed307bf 100644
--- a/lib/rtl/rtl_source_c.cc
+++ b/lib/rtl/rtl_source_c.cc
@@ -347,37 +347,31 @@ int rtl_source_c::work( int noutput_items,
   if (!_running)
     return WORK_DONE;
 
-  unsigned short *buf = _buf[_buf_head] + _buf_offset;
+  while (noutput_items && _buf_used) {
+    const int nout = std::min(noutput_items, _samp_avail);
+    const unsigned short *buf = _buf[_buf_head] + _buf_offset;
 
-  if (noutput_items <= _samp_avail) {
-    for (int i = 0; i < noutput_items; ++i)
+    for (int i = 0; i < nout; ++i)
       *out++ = _lut[ *(buf + i) ];
 
-    _buf_offset += noutput_items;
-    _samp_avail -= noutput_items;
-  } else {
-    for (int i = 0; i < _samp_avail; ++i)
-      *out++ = _lut[ *(buf + i) ];
+    noutput_items -= nout;
+    _samp_avail -= nout;
 
-    {
-      boost::mutex::scoped_lock lock( _buf_mutex );
+    if (!_samp_avail) {
+      {
+        boost::mutex::scoped_lock lock( _buf_mutex );
 
-      _buf_head = (_buf_head + 1) % _buf_num;
-      _buf_used--;
+        _buf_head = (_buf_head + 1) % _buf_num;
+        _buf_used--;
+      }
+      _samp_avail = _buf_len / BYTES_PER_SAMPLE;
+      _buf_offset = 0;
+    } else {
+      _buf_offset += nout;
     }
-
-    buf = _buf[_buf_head];
-
-    int remaining = noutput_items - _samp_avail;
-
-    for (int i = 0; i < remaining; ++i)
-      *out++ = _lut[ *(buf + i) ];
-
-    _buf_offset = remaining;
-    _samp_avail = (_buf_len / BYTES_PER_SAMPLE) - remaining;
   }
 
-  return noutput_items;
+  return (out - ((gr_complex *)output_items[0]));
 }
 
 std::vector<std::string> rtl_source_c::get_devices()