fix parsing demos that have game events before the definitions

src/demo/message/gameevent.rs

@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use std::iter::FromIterator;
 
 use bitstream_reader::{BitRead, LittleEndian};
+use parse_display::Display;
 
 use crate::demo::gameevent_gen::GameEventType;
 use crate::demo::gamevent::{
@@ -34,6 +35,17 @@ impl Parse for GameEventMessage {
         let length: u16 = stream.read_sized(11)?;
         let mut data = stream.read_bits(length as usize)?;
         let event_type: GameEventTypeId = data.read()?;
+
+        // game event definitions haven't been sent yet, ignore
+        if state.event_definitions.len() == 0 {
+            return Ok(GameEventMessage {
+                event: Box::new(GameEvent::Unknown(RawGameEvent {
+                    event_type: GameEventType::Unknown,
+                    values: Vec::new(),
+                })),
+            });
+        }
+
         let raw_event = match state.event_definitions.get(usize::from(event_type)) {
             Some(definition) => {
                 let mut values: Vec<GameEventValue> = Vec::with_capacity(definition.entries.len());
@@ -46,7 +58,12 @@ impl Parse for GameEventMessage {
                     values,
                 }
             }
-            None => return Err(ParseError::MalformedGameEvent(GameEventError::UnknownType)),
+            None => {
+                dbg!(state.event_definitions.len());
+                return Err(ParseError::MalformedGameEvent(GameEventError::UnknownType(
+                    event_type,
+                )));
+            }
         };
         let event = GameEvent::from_raw_event(raw_event)?;
         Ok(GameEventMessage {
@@ -62,7 +79,7 @@ impl ParseBitSkip for GameEventMessage {
     }
 }
 
-#[derive(BitRead, Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[derive(BitRead, Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Display)]
 pub struct GameEventTypeId(#[size = 9] u16);
 
 impl From<GameEventTypeId> for usize {

src/demo/message/packetentities.rs

@@ -154,7 +154,7 @@ impl Parse for PacketEntitiesMessage {
 
         for _ in 0..updated_entries {
             let diff: u32 = read_bit_var(&mut data)?;
-            last_index += diff as i32 + 1;
+            last_index = last_index.saturating_add(diff as i32).saturating_add(1);
             let entity_index = EntityId::from(last_index as u32);
 
             let pvs = data.read()?;

src/demo/parser/error.rs

@@ -1,4 +1,5 @@
 use crate::demo::gamevent::GameEventValueType;
+use crate::demo::message::gameevent::GameEventTypeId;
 use crate::demo::message::packetentities::EntityId;
 use crate::demo::packet::datatable::{ClassId, SendTableName};
 use bitstream_reader::{FromUtf8Error, ReadError};
@@ -46,7 +47,7 @@ pub enum ParseError {
     DataRemaining(usize),
     #[error(display = "String table with index {} not found", _0)]
     StringTableNotFound(u8),
-    #[error(display = "A malformed game event was read")]
+    #[error(display = "A malformed game event was read: {}", _0)]
     MalformedGameEvent(#[error(source)] GameEventError),
     #[error(
         display = "A read game event doesn't contain the expected values, expected type {} for {} event, got type {}",
@@ -95,8 +96,8 @@ pub enum GameEventError {
     IncorrectValueCount,
     #[error(display = "Event with 'none' value")]
     NoneValue,
-    #[error(display = "Unknown type")]
-    UnknownType,
+    #[error(display = "Unknown type: {}", _0)]
+    UnknownType(GameEventTypeId),
 }
 
 impl From<ReadError> for ParseError {