bindings/csharp: Update the C# bindings to match the new libiio API.

Add new objects for iio_attr and iio_event, fix existing IIO objects
and update the ExampleProgram.cs file.
Add a new C# example for IIO events similar to the iio_event.c.

Signed-off-by: AlexandraTrifan <Alexandra.Trifan@analog.com>

bindings/csharp/Attr.cs

@@ -10,35 +10,69 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading.Tasks;
 
 namespace iio
 {
     /// <summary><see cref="iio.Attr"/> class:
-    /// Contains the representation of a channel or device attribute.</summary>
-    public abstract class Attr
+    /// Contains the representation of an iio_attr.</summary>
+    public class Attr
     {
+        [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
+        private static extern int iio_attr_read_raw(IntPtr attr,
+                [Out()] StringBuilder dst, uint len);
+
+        [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
+        private static extern int iio_attr_write_raw(IntPtr attr, IntPtr src,
+                uint len);
+
+        [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
+        private static extern IntPtr iio_attr_get_name(IntPtr attr);
+
+        [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
+        private static extern IntPtr iio_attr_get_filename(IntPtr attr);
+
+        [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
+        private static extern IntPtr iio_attr_get_static_value(IntPtr attr);
+
+        internal IntPtr attr;
+
         /// <summary>The name of this attribute.</summary>
         public readonly string name;
 
         /// <summary>The filename in sysfs to which this attribute is bound.</summary>
         public readonly string filename;
 
-        internal Attr(string name, string filename = null)
+        internal Attr(IntPtr attr)
         {
-            this.filename = filename == null ? name : filename;
-            this.name = name;
+            this.attr = attr;
+            this.name = Marshal.PtrToStringAnsi(iio_attr_get_name(attr));
+            this.filename = Marshal.PtrToStringAnsi(iio_attr_get_filename(attr));
         }
 
         /// <summary>Read the value of this attribute as a <c>string</c>.</summary>
         /// <exception cref="IioLib.IIOException">The attribute could not be read.</exception>
-        public abstract string read();
+        public string read()
+        {
+            StringBuilder builder = new StringBuilder(1024);
+            int err = iio_attr_read_raw(attr, builder, (uint)builder.Capacity);
+            if (err < 0)
+                throw new IIOException("Unable to read attribute", err);
+            return builder.ToString();
+        }
 
         /// <summary>Set this attribute to the value contained in the <c>string</c> argument.</summary>
         /// <param name="val">The <c>string</c> value to set the parameter to.</param>
         /// <exception cref="IioLib.IIOException">The attribute could not be written.</exception>
-        public abstract void write(string val);
+        public void write(string val)
+        {
+            IntPtr valptr = Marshal.StringToHGlobalAnsi(val);
+            int err = iio_attr_write_raw(attr, valptr, (uint)val.Length);
+            if (err < 0)
+                throw new IIOException("Unable to write attribute", err);
+        }
 
         /// <summary>Read the value of this attribute as a <c>bool</c>.</summary>
         /// <exception cref="IioLib.IIOException">The attribute could not be read.</exception>

bindings/csharp/Block.cs

@@ -66,7 +66,9 @@ public Block(IOBuffer buf, uint size)
 
         protected override void Destroy()
         {
-            iio_block_destroy(hdl);
+            if (!stream_block) {
+                iio_block_destroy(hdl);
+            }
         }
 
         public int enqueue(uint bytes_used = 0, bool cyclic = false)

bindings/csharp/CMakeLists.txt

@@ -43,7 +43,9 @@ if (MCS_EXECUTABLE)
 		${CMAKE_CURRENT_SOURCE_DIR}/ChannelsMask.cs
 		${CMAKE_CURRENT_SOURCE_DIR}/Context.cs
 		${CMAKE_CURRENT_SOURCE_DIR}/Device.cs
+		${CMAKE_CURRENT_SOURCE_DIR}/EventStream.cs
 		${CMAKE_CURRENT_SOURCE_DIR}/IOBuffer.cs
+		${CMAKE_CURRENT_SOURCE_DIR}/IIOEvent.cs
 		${CMAKE_CURRENT_SOURCE_DIR}/Trigger.cs
 		${CMAKE_CURRENT_SOURCE_DIR}/IioLib.cs
 		${CMAKE_CURRENT_SOURCE_DIR}/Scan.cs

bindings/csharp/Channel.cs

@@ -20,42 +20,6 @@ namespace iio
     /// Contains the representation of an input or output channel.</summary>
     public class Channel
     {
-        private class ChannelAttr : Attr
-        {
-            private IntPtr chn;
-
-            [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
-            private static extern int iio_channel_attr_read_raw(IntPtr chn, [In()] string name, [Out()] StringBuilder val, uint len);
-
-            [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
-            private static extern int iio_channel_attr_write_string(IntPtr chn, [In()] string name, string val);
-
-            [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
-            private static extern IntPtr iio_channel_attr_get_filename(IntPtr chn, [In()] string attr);
-
-            public ChannelAttr(IntPtr chn, string name) : base(name, Marshal.PtrToStringAnsi(iio_channel_attr_get_filename(chn, name)))
-            {
-                this.chn = chn;
-            }
-
-            public override string read()
-            {
-                StringBuilder builder = new StringBuilder(1024);
-                int err = iio_channel_attr_read_raw(chn, name, builder, (uint) builder.Capacity);
-                if (err < 0)
-                    throw new IIOException("Unable to read channel attribute", err);
-
-                return builder.ToString();
-            }
-
-            public override void write(string str)
-            {
-                int err = iio_channel_attr_write_string(chn, name, str);
-                if (err < 0)
-                    throw new IIOException("Unable to write channel attribute", err);
-            }
-        }
-
         /// <summary><see cref="iio.Channel.ChannelModifier"/> class:
         /// Contains the available channel modifiers.</summary>
         public enum ChannelModifier
@@ -104,7 +68,15 @@ public enum ChannelModifier
             IIO_MOD_PM10,
             IIO_MOD_ETHANOL,
             IIO_MOD_H2,
-            IIO_MOD_O2
+            IIO_MOD_O2,
+            IIO_MOD_LINEAR_X,
+            IIO_MOD_LINEAR_Y,
+            IIO_MOD_LINEAR_Z,
+            IIO_MOD_PITCH,
+            IIO_MOD_YAW,
+            IIO_MOD_ROLL,
+            IIO_MOD_LIGHT_UVA,
+            IIO_MOD_LIGHT_UVB
         }
 
         /// <summary><see cref="iio.Channel.ChannelType"/> class:
@@ -146,6 +118,10 @@ public enum ChannelType
             IIO_POSITIONRELATIVE,
             IIO_PHASE,
             IIO_MASSCONCENTRATION,
+            IIO_DELTA_ANGL,
+            IIO_DELTA_VELOCITY,
+            IIO_COLORTEMP,
+            IIO_CHROMATICITY,
             IIO_CHAN_TYPE_UNKNOWN = Int32.MaxValue
         }
 
@@ -177,6 +153,9 @@ public struct DataFormat
 
             /// <summary>Number of times length repeats</summary>
             public uint repeat;
+
+            /// <summary>Contains a value to be added to the raw sample before applying the scale.</summary>
+            public double offset;
         }
 
         internal IntPtr chn;
@@ -281,7 +260,7 @@ internal Channel(Device dev, IntPtr chn)
 
             for (uint i = 0; i < nb_attrs; i++)
             {
-                attrs.Add(new ChannelAttr(this.chn, Marshal.PtrToStringAnsi(iio_channel_get_attr(chn, i))));
+                attrs.Add(new Attr(iio_channel_get_attr(chn, i)));
             }
 
             IntPtr name_ptr = iio_channel_get_name(this.chn);

bindings/csharp/Context.cs

@@ -91,7 +91,7 @@ private static extern IIOPtr iio_create_context(IntPtr ctx_params,
         private static extern uint iio_context_get_attrs_count(IntPtr ctx);
 
         [DllImport(IioLib.dllname, CallingConvention = CallingConvention.Cdecl)]
-        private static extern int iio_context_get_attr(IntPtr ctx, uint index, out IntPtr name_ptr, out IntPtr value_ptr);
+        private static extern IntPtr iio_context_get_attr(IntPtr ctx, uint index);
 
         /// <summary>A XML representation of the current context.</summary>
         public readonly string xml;
@@ -153,14 +153,8 @@ private Context(IIOPtr ptr)
 
             for (uint i = 0; i < nbAttrs; i++)
             {
-                IntPtr name_ptr;
-                IntPtr value_ptr;
-
-                iio_context_get_attr(hdl, i, out name_ptr, out value_ptr);
-                string attr_name = Marshal.PtrToStringAnsi(name_ptr);
-                string attr_value = Marshal.PtrToStringAnsi(value_ptr);
-
-                attrs[attr_name] = attr_value;
+                Attr attr = new Attr(iio_context_get_attr(hdl, i));
+                attrs[attr.name] = attr.read();
             }
         }