Merge pull request #21 from srdtrk/serdar/20-imp-std-err

imp: added "std" feature and implemented `std::error::Error`

Cargo.toml

@@ -10,6 +10,10 @@ repository = "https://github.com/noislabs/anybuf"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+default = ["std"]
+std = []
+
 [dependencies]
 
 [dev-dependencies]

src/bufany.rs

@@ -59,6 +59,43 @@ pub enum RepeatedStringError {
     InvalidUtf8,
 }
 
+impl core::fmt::Display for BufanyError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.write_str("Error decoding protobuf: ")?;
+        match self {
+            BufanyError::InvalidTag => f.write_str("Invalid tag"),
+            BufanyError::InvalidFieldNumber => {
+                f.write_str("Invalid field number, must be between 1 and 536,870,911")
+            }
+            BufanyError::UnsupportedWireType(wire_type) => {
+                write!(f, "Unsupported wire type: {}", wire_type)
+            }
+            BufanyError::ErrorDecodingVarint => f.write_str("Error decoding varint"),
+            BufanyError::UnexpectedEndOfData => f.write_str("Unexpected end of data"),
+        }
+    }
+}
+
+impl core::fmt::Display for RepeatedStringError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.write_str("Error decoding repeated string: ")?;
+        match self {
+            RepeatedStringError::TypeMismatch => {
+                f.write_str("Found a value of the wrong wire type")
+            }
+            RepeatedStringError::InvalidUtf8 => {
+                f.write_str("A variable length field did not contain valid UTF-8")
+            }
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for BufanyError {}
+
+#[cfg(feature = "std")]
+impl std::error::Error for RepeatedStringError {}
+
 impl Bufany<'_> {
     /// Creates an empty instance with the given lifetime.
     ///

src/varint.rs

@@ -55,9 +55,7 @@ pub fn read_unsigned_varint(data: &mut SliceReader) -> Option<u64> {
     // If byte_counter becomes 10, the `value << (byte_counter * 7)` performs a
     // left shift of 70 bits on a u64 which leads to an overflow panic.
     for byte_counter in 0..10 {
-        let Some(byte) = data.read_one() else {
-            return None;
-        };
+        let byte = data.read_one()?;
         let value = (byte & 0x7f) as u64;
         out += value << (byte_counter * 7);
         if byte & 0x80 == 0 {