add better panic messages on oob index

servicepoint2/src/bit_vec.rs

@@ -1,6 +1,7 @@
 /// A vector of bits
 #[derive(Clone, PartialEq)]
 pub struct BitVec {
+    size: usize,
     data: Vec<u8>,
 }
 
@@ -15,6 +16,7 @@ impl BitVec {
     pub fn new(size: usize) -> BitVec {
         assert_eq!(size % 8, 0);
         Self {
+            size,
             data: vec![0; size / 8],
         }
     }
@@ -73,7 +75,7 @@ impl BitVec {
 
     /// Gets the length in bits
     pub fn len(&self) -> usize {
-        self.data.len() * 8
+        self.size
     }
 
     /// returns true if length is 0.
@@ -87,9 +89,13 @@ impl BitVec {
     }
 
     /// Calculates the byte index and bitmask for a specific bit in the vector
-    fn get_indexes(&self, index: usize) -> (usize, u8) {
+    fn get_indexes(&self, bit_index: usize) -> (usize, u8) {
-        let byte_index = index / 8;
+        if bit_index >= self.size {
-        let bit_in_byte_index = 7 - index % 8;
+            panic!("bit index {bit_index} is outside of range 0..<{}", self.size)
+        }
+
+        let byte_index = bit_index / 8;
+        let bit_in_byte_index = 7 - bit_index % 8;
         let bit_mask: u8 = 1 << bit_in_byte_index;
         (byte_index, bit_mask)
     }
@@ -106,6 +112,7 @@ impl From<&[u8]> for BitVec {
     /// Interpret the data as a series of bits and load then into a new `BitVec` instance.
     fn from(value: &[u8]) -> Self {
         Self {
+            size: value.len() * 8,
             data: Vec::from(value),
         }
     }

servicepoint2/src/byte_grid.rs

@@ -38,11 +38,13 @@ impl ByteGrid {
     ///
     /// returns: current byte value
     pub fn get(&self, x: usize, y: usize) -> u8 {
+        self.check_indexes(x, y);
         self.data[x + y * self.width]
     }
 
     /// Sets the byte value at the specified position
     pub fn set(&mut self, x: usize, y: usize, value: u8) {
+        self.check_indexes(x, y);
         self.data[x + y * self.width] = value;
     }
 
@@ -65,6 +67,15 @@ impl ByteGrid {
     pub fn height(&self) -> usize {
         self.height
     }
+
+    fn check_indexes(&self, x: usize, y: usize) {
+        if x >= self.width {
+            panic!("cannot access byte {x}-{y} because x is outside of bounds 0..{}", self.width)
+        }
+        if y >= self.height {
+            panic!("cannot access byte {x}-{y} because y is outside of bounds 0..{}", self.height)
+        }
+    }
 }
 
 impl From<ByteGrid> for Vec<u8> {

servicepoint2/src/command.rs

@@ -706,7 +706,7 @@ mod tests {
     fn error_reserved_used() {
         let Packet(header, payload)
             = Command::BitmapLinear(0, BitVec::new(8), CompressionCode::Uncompressed).into();
-        let Header(command, offset, length, sub, reserved) = header;
+        let Header(command, offset, length, sub, _reserved) = header;
         let p = Packet(Header(command, offset, length, sub, 69), payload);
         assert_eq!(
             Command::try_from(p),
@@ -717,7 +717,7 @@ mod tests {
     fn error_invalid_compression() {
         let Packet(header, payload)
             = Command::BitmapLinear(0, BitVec::new(8), CompressionCode::Uncompressed).into();
-        let Header(command, offset, length, sub, reserved) = header;
+        let Header(command, offset, length, _sub, reserved) = header;
         let p = Packet(Header(command, offset, length, 42, reserved), payload);
         assert_eq!(
             Command::try_from(p),

servicepoint2/src/connection.rs

@@ -51,7 +51,7 @@ impl Connection {
     ///  pixels.fill(true);
     ///
     ///  // send pixels to display
-    ///  connection.send(servicepoint2::Command::BitmapLinearWin(servicepoint2::Origin::top_left(), pixels, CompressionCode::Lzma).into())
+    ///  connection.send(servicepoint2::Command::BitmapLinearWin(servicepoint2::Origin(0, 0), pixels, CompressionCode::Lzma).into())
     ///     .expect("send failed");
     /// ```
     pub fn send(&self, packet: Packet) -> Result<(), std::io::Error> {

servicepoint2/src/pixel_grid.rs

@@ -60,6 +60,7 @@ impl PixelGrid {
 
     /// Sets the byte value at the specified position
     pub fn set(&mut self, x: usize, y: usize, value: bool) -> bool {
+        self.check_indexes(x, y);
         self.bit_vec.set(x + y * self.width, value)
     }
 
@@ -88,6 +89,15 @@ impl PixelGrid {
     pub fn height(&self) -> usize {
         self.height
     }
+
+    fn check_indexes(&self, x: usize, y: usize) {
+        if x >= self.width {
+            panic!("cannot access pixel {x}-{y} because x is outside of bounds 0..{}", self.width)
+        }
+        if y >= self.height {
+            panic!("cannot access pixel {x}-{y} because y is outside of bounds 0..{}", self.height)
+        }
+    }
 }
 
 impl From<PixelGrid> for Vec<u8> {