Add SGB module

src/sgb.rs

@@ -0,0 +1,37 @@
+// SPDX-FileCopyrightText: 2024 Joshua Goins <josh@redstrate.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+use std::io::Cursor;
+
+use crate::ByteSpan;
+use binrw::binrw;
+use binrw::BinRead;
+
+#[binrw]
+#[derive(Debug)]
+#[brw(little)]
+struct SgbHeader {
+    #[br(count = 4)]
+    #[bw(pad_size_to = 4)]
+    #[bw(map = |x : &String | x.as_bytes())]
+    #[br(map = | x: Vec<u8> | String::from_utf8(x).unwrap().trim_matches(char::from(0)).to_string())]
+    pub identifier: String,
+
+    file_size: i32,
+    total_chunk_count: i32
+}
+
+#[derive(Debug)]
+pub struct Sgb {
+
+}
+
+impl Sgb {
+    /// Reads an existing SGB file
+    pub fn from_existing(buffer: ByteSpan) -> Option<Self> {
+        let mut cursor = Cursor::new(buffer);
+        let header = SgbHeader::read(&mut cursor).ok()?;
+
+        Some(Sgb{})
+    }
+}