feat: use cursors instead of byte arrays

src/ext.rs

@@ -0,0 +1,40 @@
+use std::io::{Cursor, Read};
+
+pub trait CursorExt {
+    fn read_u8(&mut self) -> anyhow::Result<u8>;
+    fn read_u16(&mut self) -> anyhow::Result<u16>;
+    fn read_u32(&mut self) -> anyhow::Result<u32>;
+    fn read_bytes(&mut self, len: usize) -> anyhow::Result<Vec<u8>>;
+    fn read_string(&mut self, len: usize) -> anyhow::Result<String>;
+}
+
+impl CursorExt for Cursor<&[u8]> {
+    fn read_u8(&mut self) -> anyhow::Result<u8> {
+        let mut result = [0u8; 1];
+        self.read_exact(&mut result)?;
+        Ok(result[0])
+    }
+
+    fn read_u16(&mut self) -> anyhow::Result<u16> {
+        let mut result = [0u8; 2];
+        self.read_exact(&mut result)?;
+        Ok(u16::from_be_bytes(result))
+    }
+
+    fn read_u32(&mut self) -> anyhow::Result<u32> {
+        let mut result = [0u8; 4];
+        self.read_exact(&mut result)?;
+        Ok(u32::from_be_bytes(result))
+    }
+
+    fn read_bytes(&mut self, len: usize) -> anyhow::Result<Vec<u8>> {
+        let mut result = vec![0u8; len];
+        self.read_exact(&mut result)?;
+        Ok(result)
+    }
+
+    fn read_string(&mut self, len: usize) -> anyhow::Result<String> {
+        let result = self.read_bytes(len)?;
+        Ok(String::from_utf8_lossy(&result).to_string())
+    }
+}