1 files changed, 95 insertions, 0 deletions
diff --git a/src/error/mod.rs b/src/error/mod.rs
new file mode 100644
index 0000000..4582394
--- /dev/null
+++ b/src/error/mod.rs
@@ -0,0 +1,95 @@
+// Copyright 2022-2024 Gabriel Bjørnager Jensen.
+
+use crate::checksum::Checksum;
+
+use std::error::Error as StdError;
+use std::fmt::{Display, Formatter};
+use std::process::{ExitCode, Termination};
+
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Debug)]
+pub enum Error {
+	ArrayLengthMismatch { len: usize, ok_len: usize },
+
+	DeserialiseFailure { source: Box<dyn StdError> },
+
+	EndOfDStream { len: usize, ok_len: usize },
+
+	InvalidBoolean { value: u8 },
+
+	InvalidCodePoint { value: u32 },
+
+	FixedStringTooShort { len: usize, s: String },
+
+	InvalidPackageLength { len: usize, ok_len: usize },
+
+	NullInteger,
+
+	PackageChecksumMismatch { sum: Checksum, ok_sum: Checksum },
+}
+
+impl Display for Error {
+	fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
+		use Error::*;
+
+		match *self {
+			ArrayLengthMismatch { len, ok_len } => {
+				write!(f, "expected array of length ({ok_len}) but got ({len}) elements")
+			},
+
+			DeserialiseFailure { ref source } => {
+				write!(f, "unable to deserialise: \"{source}\"")
+			},
+
+			EndOfDStream { len, ok_len } => {
+				write!(f, "({ok_len}) byte(s) were requested but only ({len}) byte(s) were left")
+			},
+
+			FixedStringTooShort { len, ref s } => {
+				write!(f, "fixed string with `N = {len}` cannot hold {s:?}")
+			},
+
+			InvalidBoolean { value } => {
+				write!(f, "expected boolean but got {value:#02X}")
+			},
+
+			InvalidCodePoint { value } => {
+				write!(f, "code point U+{value:04X} is not valid")
+			}
+
+			InvalidPackageLength { len, ok_len } => {
+				write!(f, "invalid packet length: expected at most ({ok_len}) byte(s) but got ({len}) byte(s)")
+			},
+
+			NullInteger => {
+				write!(f, "expected non-zero integer but got (0)")
+			},
+
+			PackageChecksumMismatch { ref sum, ref ok_sum } => {
+				write!(f, "expected packet checksum {ok_sum} but got {sum}")
+			},
+		}
+	}
+}
+
+impl StdError for Error {
+	fn source(&self) -> Option<&(dyn StdError + 'static)> {
+		use Error::*;
+
+		match *self {
+			DeserialiseFailure { ref source } => Some(source.as_ref()),
+
+			_ => None,
+		}
+	}
+}
+
+impl From<Error> for i32 {
+	fn from(_: Error) -> Self { 0x1 }
+}
+
+impl Termination for Error {
+	#[inline(always)]
+	fn report(self) -> ExitCode { ExitCode::FAILURE }
+}