Merge pull request #147 from GrantM11235/infallible-fill-params-buf

Make fill_params_buf infallible

mipidsi/src/dcs.rs

@@ -32,7 +32,7 @@ pub trait DcsCommand {
     fn instruction(&self) -> u8;
 
     /// Fills the given buffer with the command parameters.
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error>;
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize;
 }
 
 /// Wrapper around [`WriteOnlyDataCommand`] with support for writing DCS commands.
@@ -66,7 +66,7 @@ where
     /// Sends a DCS command to the display interface.
     pub fn write_command(&mut self, command: impl DcsCommand) -> Result<(), Error> {
         let mut param_bytes: [u8; 16] = [0; 16];
-        let n = command.fill_params_buf(&mut param_bytes)?;
+        let n = command.fill_params_buf(&mut param_bytes);
         self.write_raw(command.instruction(), &param_bytes[..n])
     }
 

mipidsi/src/dcs/macros.rs

@@ -12,8 +12,8 @@ macro_rules! dcs_basic_command {
                 $instr
             }
 
-            fn fill_params_buf(&self, _buffer: &mut [u8]) -> Result<usize, Error> {
-                Ok(0)
+            fn fill_params_buf(&self, _buffer: &mut [u8]) -> usize {
+                0
             }
         }
     };

mipidsi/src/dcs/set_address_mode.rs

@@ -1,6 +1,5 @@
 //! Module for the MADCTL instruction constructors
 
-use crate::error::Error;
 use crate::options::{
     ColorOrder, HorizontalRefreshOrder, MemoryMapping, ModelOptions, Orientation, RefreshOrder,
     VerticalRefreshOrder,
@@ -79,9 +78,9 @@ impl DcsCommand for SetAddressMode {
         0x36
     }
 
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error> {
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize {
         buffer[0] = self.0;
-        Ok(1)
+        1
     }
 }
 
@@ -101,7 +100,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn madctl_bit_operations() -> Result<(), Error> {
+    fn madctl_bit_operations() {
         let madctl = SetAddressMode::default()
             .with_color_order(ColorOrder::Bgr)
             .with_refresh_order(RefreshOrder::new(
@@ -111,21 +110,19 @@ mod tests {
             .with_orientation(Orientation::default().rotate(Rotation::Deg270));
 
         let mut bytes = [0u8];
-        assert_eq!(madctl.fill_params_buf(&mut bytes)?, 1);
+        assert_eq!(madctl.fill_params_buf(&mut bytes), 1);
         assert_eq!(bytes, [0b1011_1100u8]);
 
         let madctl = madctl.with_orientation(Orientation::default());
-        assert_eq!(madctl.fill_params_buf(&mut bytes)?, 1);
+        assert_eq!(madctl.fill_params_buf(&mut bytes), 1);
         assert_eq!(bytes, [0b0001_1100u8]);
 
         let madctl = madctl.with_color_order(ColorOrder::Rgb);
-        assert_eq!(madctl.fill_params_buf(&mut bytes)?, 1);
+        assert_eq!(madctl.fill_params_buf(&mut bytes), 1);
         assert_eq!(bytes, [0b0001_0100u8]);
 
         let madctl = madctl.with_refresh_order(RefreshOrder::default());
-        assert_eq!(madctl.fill_params_buf(&mut bytes)?, 1);
+        assert_eq!(madctl.fill_params_buf(&mut bytes), 1);
         assert_eq!(bytes, [0b0000_0000u8]);
-
-        Ok(())
     }
 }

mipidsi/src/dcs/set_column_address.rs

@@ -1,7 +1,5 @@
 //! Module for the CASET address window instruction constructors
 
-use crate::error::Error;
-
 use super::DcsCommand;
 
 /// Set Column Address
@@ -26,11 +24,11 @@ impl DcsCommand for SetColumnAddress {
         0x2A
     }
 
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error> {
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize {
         buffer[0..2].copy_from_slice(&self.start_column.to_be_bytes());
         buffer[2..4].copy_from_slice(&self.end_column.to_be_bytes());
 
-        Ok(4)
+        4
     }
 }
 
@@ -39,13 +37,11 @@ mod tests {
     use super::*;
 
     #[test]
-    fn caset_fills_data_properly() -> Result<(), Error> {
+    fn caset_fills_data_properly() {
         let caset = SetColumnAddress::new(0, 320);
 
         let mut buffer = [0u8; 4];
-        assert_eq!(caset.fill_params_buf(&mut buffer)?, 4);
+        assert_eq!(caset.fill_params_buf(&mut buffer), 4);
         assert_eq!(buffer, [0, 0, 0x1, 0x40]);
-
-        Ok(())
     }
 }

mipidsi/src/dcs/set_invert_mode.rs

@@ -1,4 +1,3 @@
-use crate::error::Error;
 use crate::options::ColorInversion;
 
 use super::DcsCommand;
@@ -22,8 +21,8 @@ impl DcsCommand for SetInvertMode {
         }
     }
 
-    fn fill_params_buf(&self, _buffer: &mut [u8]) -> Result<usize, Error> {
-        Ok(0)
+    fn fill_params_buf(&self, _buffer: &mut [u8]) -> usize {
+        0
     }
 }
 
@@ -32,13 +31,11 @@ mod tests {
     use super::*;
 
     #[test]
-    fn set_invert_mode_chooses_correct_instruction() -> Result<(), Error> {
+    fn set_invert_mode_chooses_correct_instruction() {
         let ste = SetInvertMode(ColorInversion::Inverted);
 
         let mut buffer = [0u8; 0];
         assert_eq!(ste.instruction(), 0x21);
-        assert_eq!(ste.fill_params_buf(&mut buffer)?, 0);
-
-        Ok(())
+        assert_eq!(ste.fill_params_buf(&mut buffer), 0);
     }
 }

mipidsi/src/dcs/set_page_address.rs

@@ -1,7 +1,5 @@
 //! Module for the RASET address window instruction constructors
 
-use crate::error::Error;
-
 use super::DcsCommand;
 
 /// Set Page Address
@@ -23,11 +21,11 @@ impl DcsCommand for SetPageAddress {
         0x2B
     }
 
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error> {
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize {
         buffer[0..2].copy_from_slice(&self.start_row.to_be_bytes());
         buffer[2..4].copy_from_slice(&self.end_row.to_be_bytes());
 
-        Ok(4)
+        4
     }
 }
 
@@ -36,13 +34,11 @@ mod tests {
     use super::*;
 
     #[test]
-    fn raset_fills_data_properly() -> Result<(), Error> {
+    fn raset_fills_data_properly() {
         let raset = SetPageAddress::new(0, 320);
 
         let mut buffer = [0u8; 4];
-        assert_eq!(raset.fill_params_buf(&mut buffer)?, 4);
+        assert_eq!(raset.fill_params_buf(&mut buffer), 4);
         assert_eq!(buffer, [0, 0, 0x1, 0x40]);
-
-        Ok(())
     }
 }

mipidsi/src/dcs/set_pixel_format.rs

@@ -1,7 +1,5 @@
 //! Module for the COLMOD instruction constructors
 
-use crate::error::Error;
-
 use super::DcsCommand;
 
 /// Set Pixel Format
@@ -20,9 +18,9 @@ impl DcsCommand for SetPixelFormat {
         0x3A
     }
 
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error> {
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize {
         buffer[0] = self.0.as_u8();
-        Ok(1)
+        1
     }
 }
 
@@ -85,45 +83,39 @@ mod tests {
     use super::*;
 
     #[test]
-    fn colmod_rgb565_is_16bit() -> Result<(), Error> {
+    fn colmod_rgb565_is_16bit() {
         let colmod = SetPixelFormat::new(PixelFormat::new(
             BitsPerPixel::Sixteen,
             BitsPerPixel::Sixteen,
         ));
 
         let mut bytes = [0u8];
-        assert_eq!(colmod.fill_params_buf(&mut bytes)?, 1);
+        assert_eq!(colmod.fill_params_buf(&mut bytes), 1);
         assert_eq!(bytes, [0b0101_0101u8]);
-
-        Ok(())
     }
 
     #[test]
-    fn colmod_rgb666_is_18bit() -> Result<(), Error> {
+    fn colmod_rgb666_is_18bit() {
         let colmod = SetPixelFormat::new(PixelFormat::new(
             BitsPerPixel::Eighteen,
             BitsPerPixel::Eighteen,
         ));
 
         let mut bytes = [0u8];
-        assert_eq!(colmod.fill_params_buf(&mut bytes)?, 1);
+        assert_eq!(colmod.fill_params_buf(&mut bytes), 1);
         assert_eq!(bytes, [0b0110_0110u8]);
-
-        Ok(())
     }
 
     #[test]
-    fn colmod_rgb888_is_24bit() -> Result<(), Error> {
+    fn colmod_rgb888_is_24bit() {
         let colmod = SetPixelFormat::new(PixelFormat::new(
             BitsPerPixel::Eighteen,
             BitsPerPixel::TwentyFour,
         ));
 
         let mut bytes = [0u8];
-        assert_eq!(colmod.fill_params_buf(&mut bytes)?, 1);
+        assert_eq!(colmod.fill_params_buf(&mut bytes), 1);
         assert_eq!(bytes, [0b0110_0111u8]);
-
-        Ok(())
     }
 
     #[test]

mipidsi/src/dcs/set_scroll_area.rs

@@ -1,7 +1,5 @@
 //! Module for the VSCRDEF visual scroll definition instruction constructors
 
-use crate::error::Error;
-
 use super::DcsCommand;
 
 /// Set Scroll Area
@@ -26,7 +24,7 @@ impl DcsCommand for SetScrollArea {
         0x33
     }
 
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error> {
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize {
         let tfa_bytes = self.tfa.to_be_bytes();
         let vsa_bytes = self.vsa.to_be_bytes();
         let bfa_bytes = self.bfa.to_be_bytes();
@@ -38,7 +36,7 @@ impl DcsCommand for SetScrollArea {
         buffer[4] = bfa_bytes[0];
         buffer[5] = bfa_bytes[1];
 
-        Ok(6)
+        6
     }
 }
 
@@ -47,13 +45,11 @@ mod tests {
     use super::*;
 
     #[test]
-    fn vscrdef_fills_buffer_properly() -> Result<(), Error> {
+    fn vscrdef_fills_buffer_properly() {
         let vscrdef = SetScrollArea::new(0, 320, 0);
 
         let mut buffer = [0u8; 6];
-        assert_eq!(vscrdef.fill_params_buf(&mut buffer)?, 6);
+        assert_eq!(vscrdef.fill_params_buf(&mut buffer), 6);
         assert_eq!(buffer, [0, 0, 0x1, 0x40, 0, 0]);
-
-        Ok(())
     }
 }

mipidsi/src/dcs/set_scroll_start.rs

@@ -1,7 +1,5 @@
 //! Module for the VSCAD visual scroll offset instruction constructors
 
-use crate::error::Error;
-
 use super::DcsCommand;
 
 /// Set Scroll Start
@@ -20,12 +18,12 @@ impl DcsCommand for SetScrollStart {
         0x37
     }
 
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error> {
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize {
         let bytes = self.0.to_be_bytes();
         buffer[0] = bytes[0];
         buffer[1] = bytes[1];
 
-        Ok(2)
+        2
     }
 }
 
@@ -34,13 +32,11 @@ mod tests {
     use super::*;
 
     #[test]
-    fn vscad_fills_offset_properly() -> Result<(), Error> {
+    fn vscad_fills_offset_properly() {
         let vscad = SetScrollStart::new(320);
 
         let mut buffer = [0u8; 2];
-        assert_eq!(vscad.fill_params_buf(&mut buffer)?, 2);
+        assert_eq!(vscad.fill_params_buf(&mut buffer), 2);
         assert_eq!(buffer, [0x1, 0x40]);
-
-        Ok(())
     }
 }

mipidsi/src/dcs/set_tearing_effect.rs

@@ -1,4 +1,3 @@
-use crate::error::Error;
 use crate::options::TearingEffect;
 
 use super::DcsCommand;
@@ -23,16 +22,16 @@ impl DcsCommand for SetTearingEffect {
         }
     }
 
-    fn fill_params_buf(&self, buffer: &mut [u8]) -> Result<usize, Error> {
+    fn fill_params_buf(&self, buffer: &mut [u8]) -> usize {
         match self.0 {
-            TearingEffect::Off => Ok(0),
+            TearingEffect::Off => 0,
             TearingEffect::Vertical => {
                 buffer[0] = 0x0;
-                Ok(1)
+                1
             }
             TearingEffect::HorizontalAndVertical => {
                 buffer[0] = 0x1;
-                Ok(1)
+                1
             }
         }
     }
@@ -43,25 +42,21 @@ mod tests {
     use super::*;
 
     #[test]
-    fn set_tearing_effect_both_fills_param_properly() -> Result<(), Error> {
+    fn set_tearing_effect_both_fills_param_properly() {
         let ste = SetTearingEffect(TearingEffect::HorizontalAndVertical);
 
         let mut buffer = [0u8; 1];
         assert_eq!(ste.instruction(), 0x35);
-        assert_eq!(ste.fill_params_buf(&mut buffer)?, 1);
+        assert_eq!(ste.fill_params_buf(&mut buffer), 1);
         assert_eq!(buffer, [0x1]);
-
-        Ok(())
     }
 
     #[test]
-    fn set_tearing_effect_off_fills_param_properly() -> Result<(), Error> {
+    fn set_tearing_effect_off_fills_param_properly() {
         let ste = SetTearingEffect(TearingEffect::Off);
 
         let mut buffer = [0u8; 0];
         assert_eq!(ste.instruction(), 0x34);
-        assert_eq!(ste.fill_params_buf(&mut buffer)?, 0);
-
-        Ok(())
+        assert_eq!(ste.fill_params_buf(&mut buffer), 0);
     }
 }