Add initial support for SVB files

Don't know what these are yet, but very similar to the other ones
I just implemented.

src/lib.rs

@@ -146,6 +146,9 @@ pub mod lcb;
 /// Reading LVB files
 pub mod lvb;
 
+/// Reading SVB files
+pub mod svb;
+
 mod bcn;
 
 mod error;

src/svb.rs

@@ -0,0 +1,88 @@
+// SPDX-FileCopyrightText: 2025 Joshua Goins <josh@redstrate.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+use std::io::Cursor;
+
+use crate::ByteBuffer;
+use crate::ByteSpan;
+use binrw::BinRead;
+use binrw::BinWrite;
+use binrw::binrw;
+
+#[binrw]
+#[derive(Debug)]
+#[brw(little)]
+#[brw(magic = b"SVB1")]
+pub struct Svb {
+    /// Including this header
+    pub file_size: u32,
+    /// Number of Svc's
+    #[br(temp)]
+    #[bw(calc = svcs.len() as u32)]
+    svc_count: u32,
+    #[br(count = svc_count)]
+    pub svcs: Vec<Svc>,
+}
+
+#[binrw]
+#[derive(Debug)]
+#[brw(little)]
+#[brw(magic = b"SVC1")]
+pub struct Svc {
+    #[br(temp)]
+    #[bw(calc = entries.len() as u32 + 1)]
+    pub num_entries: u32,
+    #[brw(pad_before = 4)] // empty?
+    pub unk1: u32,
+    pub unk2: u32,
+    // TODO: figure out what this is
+    // TODO: why is it -1?
+    #[br(count = num_entries - 1)]
+    pub entries: Vec<SvcEntry>,
+}
+
+#[binrw]
+#[derive(Debug)]
+#[brw(little)]
+pub struct SvcEntry {
+    // TODO: figure out what this is
+    #[br(count = 48)]
+    pub unk1: Vec<u8>,
+}
+
+impl Svb {
+    /// Reads an existing UWB file
+    pub fn from_existing(buffer: ByteSpan) -> Option<Self> {
+        let mut cursor = Cursor::new(buffer);
+        Svb::read(&mut cursor).ok()
+    }
+
+    pub fn write_to_buffer(&self) -> Option<ByteBuffer> {
+        let mut buffer = ByteBuffer::new();
+
+        {
+            let mut cursor = Cursor::new(&mut buffer);
+            self.write_le(&mut cursor).ok()?;
+        }
+
+        Some(buffer)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::fs::read;
+    use std::path::PathBuf;
+
+    use super::*;
+
+    #[test]
+    fn test_invalid() {
+        let mut d = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+        d.push("resources/tests");
+        d.push("random");
+
+        // Feeding it invalid data should not panic
+        Svb::from_existing(&read(d).unwrap());
+    }
+}