Support connection via serial number

badcel · Oct 9, 2022 · 553e166 · 553e166
1 parent d1d3c72
commit 553e166
Show file tree

Hide file tree

Showing 5 changed files with 52 additions and 2 deletions.
diff --git a/src/HidApi.Net/Device.cs b/src/HidApi.Net/Device.cs
@@ -1,3 +1,5 @@
+using System.Runtime.CompilerServices;
+
 namespace HidApi;
 
 /// <summary>
@@ -15,7 +17,21 @@ public class Device : IDisposable
     /// <param name="productId">product id of target device</param>
     public Device(ushort vendorId, ushort productId)
     {
-        handle = NativeMethods.Open(vendorId, productId, string.Empty);
+        handle = NativeMethods.Open(vendorId, productId, ref Unsafe.NullRef<byte>());
+
+        if (handle.IsInvalid)
+            HidException.Throw(handle);
+    }
+
+    /// <summary>
+    /// Connects to a given device.
+    /// </summary>
+    /// <param name="vendorId">Vendor id of target device</param>
+    /// <param name="productId">Product id of target device</param>
+    /// <param name="serialNumber">Serial number of target device</param>
+    public Device(ushort vendorId, ushort productId, string serialNumber)
+    {
+        handle = NativeMethods.Open(vendorId, productId, ref WCharT.CreateNullTerminatedString(serialNumber));
 
         if (handle.IsInvalid)
             HidException.Throw(handle);

diff --git a/src/HidApi.Net/Internal/NativeMethods.cs b/src/HidApi.Net/Internal/NativeMethods.cs
@@ -99,7 +99,7 @@ public static int GetInputReport(DeviceSafeHandle device, ReadOnlySpan<byte> dat
     public static extern unsafe void FreeEnumeration(NativeDeviceInfo* devices);
 
     [DllImport(Library, EntryPoint = "hid_open")]
-    public static extern DeviceSafeHandle Open(ushort vendorId, ushort productId, [MarshalAs(UnmanagedType.LPWStr)] string serialNumber);
+    public static extern DeviceSafeHandle Open(ushort vendorId, ushort productId, ref byte serialNumber);
 
     [DllImport(Library, EntryPoint = "hid_open_path")]
     public static extern DeviceSafeHandle OpenPath([MarshalAs(UnmanagedType.LPStr)] string path);

diff --git a/src/HidApi.Net/Internal/Unicode.cs b/src/HidApi.Net/Internal/Unicode.cs
@@ -1,9 +1,19 @@
+using System.Runtime.InteropServices;
 using System.Text;
 
 namespace HidApi;
 
 internal static class Unicode
 {
+    public static ref byte CreateNullTerminatedString(string str)
+    {
+        var src = Encoding.Unicode.GetBytes(str);
+        var dest = new byte[src.Length + sizeof(uint)];
+        Array.Copy(src, dest, src.Length);
+
+        return ref MemoryMarshal.AsRef<byte>(dest);
+    }
+
     public static ReadOnlySpan<byte> CreateBuffer(int size)
     {
         return new byte[size * sizeof(ushort)];

diff --git a/src/HidApi.Net/Internal/Utf32.cs b/src/HidApi.Net/Internal/Utf32.cs
@@ -1,9 +1,19 @@
+using System.Runtime.InteropServices;
 using System.Text;
 
 namespace HidApi;
 
 internal static class Utf32
 {
+    public static ref byte CreateNullTerminatedString(string str)
+    {
+        var src = Encoding.UTF32.GetBytes(str);
+        var dest = new byte[src.Length + sizeof(uint)];
+        Array.Copy(src, dest, src.Length);
+
+        return ref MemoryMarshal.AsRef<byte>(dest);
+    }
+
     public static ReadOnlySpan<byte> CreateBuffer(int size)
     {
         return new byte[size * sizeof(uint)];

diff --git a/src/HidApi.Net/Internal/WCharT.cs b/src/HidApi.Net/Internal/WCharT.cs
@@ -46,4 +46,18 @@ public static ReadOnlySpan<byte> CreateBuffer(int size)
 
         throw new Exception("Unsupported platform to create a buffer");
     }
+
+    public static ref byte CreateNullTerminatedString(string str)
+    {
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            return ref Utf32.CreateNullTerminatedString(str);
+
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            return ref Unicode.CreateNullTerminatedString(str);
+
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            return ref Utf32.CreateNullTerminatedString(str);
+
+        throw new Exception("Unsupported platform to create a string");
+    }
 }