Validation checks for RawImage construction

src/error.rs

@@ -1,3 +1,4 @@
+use crate::colors::{BitDepth, ColorType};
 use std::error::Error;
 use std::fmt;
 
@@ -11,6 +12,8 @@ pub enum PngError {
     InvalidData,
     TruncatedData,
     ChunkMissing(&'static str),
+    InvalidDepthForType(BitDepth, ColorType),
+    IncorrectDataLength(usize, usize),
     Other(Box<str>),
 }
 
@@ -30,6 +33,14 @@ impl fmt::Display for PngError {
             }
             PngError::APNGNotSupported => f.write_str("APNG files are not (yet) supported"),
             PngError::ChunkMissing(s) => write!(f, "Chunk {} missing or empty", s),
+            PngError::InvalidDepthForType(d, ref c) => {
+                write!(f, "Invalid bit depth {} for color type {}", d, c)
+            }
+            PngError::IncorrectDataLength(l1, l2) => write!(
+                f,
+                "Data length {} does not match the expected length {}",
+                l1, l2
+            ),
             PngError::Other(ref s) => f.write_str(s),
         }
     }

src/lib.rs

@@ -331,6 +331,24 @@ impl RawImage {
         bit_depth: BitDepth,
         data: Vec<u8>,
     ) -> Result<Self, PngError> {
+        // Validate bit depth
+        let valid_depth = match color_type {
+            ColorType::Grayscale { .. } => true,
+            ColorType::Indexed { .. } => (bit_depth as u8) <= 8,
+            _ => (bit_depth as u8) >= 8,
+        };
+        if !valid_depth {
+            return Err(PngError::InvalidDepthForType(bit_depth, color_type));
+        }
+
+        // Validate data length
+        let bpp = bit_depth as usize * color_type.channels_per_pixel() as usize;
+        let row_bytes = (bpp * width as usize + 7) / 8;
+        let expected_len = row_bytes * height as usize;
+        if data.len() != expected_len {
+            return Err(PngError::IncorrectDataLength(data.len(), expected_len));
+        }
+
         Ok(Self {
             png: Arc::new(PngImage {
                 ihdr: IhdrData {