feat: add initial implementation of rsli crate

- Created Cargo.toml for the rsli crate with flate2 dependency.
- Implemented ResourceData enum for handling borrowed and owned byte slices.
- Added OutputBuffer trait and its Vec<u8> implementation for writing data.
- Defined a comprehensive Error enum for error handling in the library.
- Developed the Library struct to manage resource entries and provide methods for loading and unpacking resources.
- Implemented various packing methods and decompression algorithms, including LZSS and Deflate.
- Added tests for validating the functionality of the rsli library against sample data.

crates/rsli/src/data.rs

@@ -0,0 +1,41 @@
+use std::io;
+
+#[derive(Clone, Debug)]
+pub enum ResourceData<'a> {
+    Borrowed(&'a [u8]),
+    Owned(Vec<u8>),
+}
+
+impl<'a> ResourceData<'a> {
+    pub fn as_slice(&self) -> &[u8] {
+        match self {
+            Self::Borrowed(slice) => slice,
+            Self::Owned(buf) => buf.as_slice(),
+        }
+    }
+
+    pub fn into_owned(self) -> Vec<u8> {
+        match self {
+            Self::Borrowed(slice) => slice.to_vec(),
+            Self::Owned(buf) => buf,
+        }
+    }
+}
+
+impl AsRef<[u8]> for ResourceData<'_> {
+    fn as_ref(&self) -> &[u8] {
+        self.as_slice()
+    }
+}
+
+pub trait OutputBuffer {
+    fn write_exact(&mut self, data: &[u8]) -> io::Result<()>;
+}
+
+impl OutputBuffer for Vec<u8> {
+    fn write_exact(&mut self, data: &[u8]) -> io::Result<()> {
+        self.clear();
+        self.extend_from_slice(data);
+        Ok(())
+    }
+}

crates/rsli/src/error.rs

@@ -0,0 +1,129 @@
+use core::fmt;
+
+#[derive(Debug)]
+#[non_exhaustive]
+pub enum Error {
+    Io(std::io::Error),
+
+    InvalidMagic {
+        got: [u8; 2],
+    },
+    UnsupportedVersion {
+        got: u8,
+    },
+    InvalidEntryCount {
+        got: i16,
+    },
+
+    EntryTableOutOfBounds {
+        table_offset: u64,
+        table_len: u64,
+        file_len: u64,
+    },
+    EntryTableDecryptFailed,
+    CorruptEntryTable(&'static str),
+
+    EntryIdOutOfRange {
+        id: u32,
+        entry_count: u32,
+    },
+    EntryDataOutOfBounds {
+        id: u32,
+        offset: u64,
+        size: u32,
+        file_len: u64,
+    },
+
+    AoTrailerInvalid,
+    MediaOverlayOutOfBounds {
+        overlay: u32,
+        file_len: u64,
+    },
+
+    UnsupportedMethod {
+        raw: u32,
+    },
+    PackedSizePastEof {
+        id: u32,
+        offset: u64,
+        packed_size: u32,
+        file_len: u64,
+    },
+    DeflateEofPlusOneQuirkRejected {
+        id: u32,
+    },
+
+    DecompressionFailed(&'static str),
+    OutputSizeMismatch {
+        expected: u32,
+        got: u32,
+    },
+
+    IntegerOverflow,
+}
+
+impl From<std::io::Error> for Error {
+    fn from(value: std::io::Error) -> Self {
+        Self::Io(value)
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Error::Io(e) => write!(f, "I/O error: {e}"),
+            Error::InvalidMagic { got } => write!(f, "invalid RsLi magic: {got:02X?}"),
+            Error::UnsupportedVersion { got } => write!(f, "unsupported RsLi version: {got:#x}"),
+            Error::InvalidEntryCount { got } => write!(f, "invalid entry_count: {got}"),
+            Error::EntryTableOutOfBounds {
+                table_offset,
+                table_len,
+                file_len,
+            } => write!(
+                f,
+                "entry table out of bounds: off={table_offset}, len={table_len}, file={file_len}"
+            ),
+            Error::EntryTableDecryptFailed => write!(f, "failed to decrypt entry table"),
+            Error::CorruptEntryTable(s) => write!(f, "corrupt entry table: {s}"),
+            Error::EntryIdOutOfRange { id, entry_count } => {
+                write!(f, "entry id out of range: id={id}, count={entry_count}")
+            }
+            Error::EntryDataOutOfBounds {
+                id,
+                offset,
+                size,
+                file_len,
+            } => write!(
+                f,
+                "entry data out of bounds: id={id}, off={offset}, size={size}, file={file_len}"
+            ),
+            Error::AoTrailerInvalid => write!(f, "invalid AO trailer"),
+            Error::MediaOverlayOutOfBounds { overlay, file_len } => {
+                write!(
+                    f,
+                    "media overlay out of bounds: overlay={overlay}, file={file_len}"
+                )
+            }
+            Error::UnsupportedMethod { raw } => write!(f, "unsupported packing method: {raw:#x}"),
+            Error::PackedSizePastEof {
+                id,
+                offset,
+                packed_size,
+                file_len,
+            } => write!(
+                f,
+                "packed range past EOF: id={id}, off={offset}, size={packed_size}, file={file_len}"
+            ),
+            Error::DeflateEofPlusOneQuirkRejected { id } => {
+                write!(f, "deflate EOF+1 quirk rejected for entry {id}")
+            }
+            Error::DecompressionFailed(s) => write!(f, "decompression failed: {s}"),
+            Error::OutputSizeMismatch { expected, got } => {
+                write!(f, "output size mismatch: expected={expected}, got={got}")
+            }
+            Error::IntegerOverflow => write!(f, "integer overflow"),
+        }
+    }
+}
+
+impl std::error::Error for Error {}