Fix saturating overflow in ExtraData parsing

- Fix overflow in ExtraData by casting byte_len to usize before
multiplication. This was previously multiplying a u16 with
saturating_mul and would overflow when the extra data in string
tables reaches a certain size.
- Add test case for parsing large string table to verify correct
stream position after read.

src/demo/packet/stringtable.rs

@@ -154,7 +154,7 @@ fn test_string_table_roundtrip() {
 #[serde(bound(deserialize = "'a: 'static"))]
 pub struct ExtraData<'a> {
     pub byte_len: u16,
-    #[size = "byte_len.saturating_mul(8)"]
+    #[size = "(byte_len as usize).saturating_mul(8)"]
     pub data: Stream<'a>,
 }
 

test_data/string_tables/ServerMapCycleLarge_meta.json

@@ -0,0 +1,4 @@
+{
+  "name": "ServerMapCycle",
+  "marker": 4039822362
+}

tests/stringtable.rs

@@ -4,7 +4,7 @@ use test_case::test_case;
 use tf_demo_parser::demo::message::stringtable::{
     parse_string_table_update, write_string_table_update, StringTableMeta,
 };
-use tf_demo_parser::demo::packet::stringtable::FixedUserDataSize;
+use tf_demo_parser::demo::packet::stringtable::{FixedUserDataSize, StringTable};
 
 #[test_case("test_data/string_tables/decalprecache.bin", "test_data/string_tables/decalprecache_meta.json"; "decalprecache")]
 #[test_case("test_data/string_tables/downloadables.bin", "test_data/string_tables/downloadables_meta.json"; "downloadables")]
@@ -67,3 +67,23 @@ fn string_table_reencode(input_file: &str, meta_file: &str) {
         pretty_assertions::assert_eq!(data, out);
     }
 }
+
+#[test_case("test_data/string_tables/ServerMapCycleLarge.bin", "test_data/string_tables/ServerMapCycleLarge_meta.json"; "ServerMapCycleLarge")]
+fn large_string_table_parsing(input_file: &str, meta_file: &str) {
+    let data = fs::read(input_file).unwrap();
+    let meta: serde_json::Value =
+        serde_json::from_str(&fs::read_to_string(meta_file).unwrap()).unwrap();
+
+    let expected_table_name = meta["name"].as_str().unwrap();
+    let expected_marker = meta["marker"].as_u64().unwrap() as u32;
+
+    let mut stream = BitReadStream::new(BitReadBuffer::new(&data, LittleEndian));
+
+    // Parse the table data
+    let table: StringTable<'_> = stream.read().unwrap();
+    pretty_assertions::assert_eq!(expected_table_name, table.name);
+
+    // Ensure the stream position is correct (previously the byte_len.saturated_mul(8) in ExtraData could overflow and would leave the BitReadStream in a bad state).
+    let marker: u32 = stream.read().unwrap();
+    pretty_assertions::assert_eq!(expected_marker, marker);
+}