added comedi_data_read_n()

diff --git a/include/comedilib.h b/include/comedilib.h
index df0104b46e386ec8e79c23b4d56c1c4d2db9b424..3e0fe7b13805dc24ceeee2dc45736fddfe4ca032 100644 (file)
--- a/include/comedilib.h
+++ b/include/comedilib.h
@@ -118,6 +118,8 @@ lsampl_t comedi_from_phys(double data,comedi_range *rng,lsampl_t maxdata);
 /* syncronous stuff */
 int comedi_data_read(comedi_t *it,unsigned int subd,unsigned int chan,
        unsigned int range,unsigned int aref,lsampl_t *data);
+int comedi_data_read_n(comedi_t *it,unsigned int subd,unsigned int chan,
+       unsigned int range,unsigned int aref,lsampl_t *data, unsigned int n);
 int comedi_data_read_hint(comedi_t *it,unsigned int subd,unsigned int chan,
        unsigned int range,unsigned int aref);
 int comedi_data_read_delayed(comedi_t *it,unsigned int subd,unsigned int chan,

diff --git a/lib/data.c b/lib/data.c
index fdec01b4eb1494e0b46120c1716d0bb872482b31..0028fc4e7b13255739f0d52b3e29cfde93d9a5e8 100644 (file)
--- a/lib/data.c
+++ b/lib/data.c
@@ -85,7 +85,7 @@ int comedi_data_write(comedi_t *it,unsigned int subdev,unsigned int chan,unsigne
        }
 }
 
-int comedi_data_read_n(comedi_t *it, unsigned int subdev, unsigned int chan, unsigned int range,
+static inline int comedi_internal_data_read_n(comedi_t *it, unsigned int subdev, unsigned int chan, unsigned int range,
                unsigned int aref, lsampl_t *data, unsigned int n)
 {
        subdevice *s;
@@ -144,17 +144,39 @@ int comedi_data_read_n(comedi_t *it, unsigned int subdev, unsigned int chan, uns
        }
 }
 
+int comedi_data_read_n(comedi_t *it, unsigned int subdev, unsigned int chan, unsigned int range,
+               unsigned int aref, lsampl_t *data, unsigned int n)
+{
+       static const int max_chunk_size = 100;
+       unsigned int chunk_size;
+       unsigned int sample_count = 0;
+       int retval;
+
+       while( n )
+       {
+               if( n > max_chunk_size)
+                       chunk_size = max_chunk_size;
+               else
+                       chunk_size = n;
+               retval = comedi_internal_data_read_n( it, subdev, chan, range, aref, &data[sample_count], chunk_size);
+               if( retval < 0 ) return retval;
+               n -= chunk_size;
+               sample_count += chunk_size;
+       }
+       return 0;
+}
+
 int comedi_data_read(comedi_t *it, unsigned int subdev, unsigned int chan, unsigned int range,
        unsigned int aref, lsampl_t *data)
 {
-       return comedi_data_read_n(it, subdev, chan, range, aref, data, 1);
+       return comedi_internal_data_read_n(it, subdev, chan, range, aref, data, 1);
 }
 
 int comedi_data_read_hint(comedi_t *it,unsigned int subdev,unsigned int chan,unsigned int range,
 unsigned int aref)
 {
        lsampl_t dummy_data;
-       return comedi_data_read_n(it, subdev, chan, range, aref, &dummy_data, 0);
+       return comedi_internal_data_read_n(it, subdev, chan, range, aref, &dummy_data, 0);
 }
 
 int comedi_data_read_delayed( comedi_t *it, unsigned int subdev, unsigned int chan, unsigned int range,