refactor(typedef): introduce TypeDefKind enum for integer dispatch

Replace all string-based TypeDef:* kind matching with a 17-variant
TypeDefKind enum. The enum provides compile-time exhaustiveness
checking, integer discriminant dispatch (jump table), and type-safe
methods (type_size, natural_alignment, is_fixed_size, etc.).

- Add TypeDefKind enum with FromStr, Display, and helper methods
- Add get_typedef_kind_enum() and get_typedef_kind_loose_enum()
- Convert DiscriminatorKind::Byte.disc_type from String to TypeDefKind
- Convert FieldPosition.kind from String to TypeDefKind
- Convert all 8 dispatch sites from string matching to enum matching
- Remove legacy string-based type_size/natural_alignment/is_fixed_size
  wrapper functions — all call sites use enum methods directly
- Update tests to use enum variants

crates/alknet-typedef/src/engine.rs

@@ -13,7 +13,7 @@ use crate::data_access;
 use crate::error::TypedefError;
 use crate::layout_builder::LayoutBuilder;
 use crate::offset_map::OffsetMap;
-use crate::schema::{self, get_typedef_kind_loose, Endian};
+use crate::schema::{self, get_typedef_kind_loose_enum, Endian, TypeDefKind};
 use crate::sequential_reader::{FieldValue, SequentialReader};
 use crate::validation;
 use serde_json::Value;
@@ -206,82 +206,80 @@ impl TypedefEngine {
                 field_path: field_path.to_string(),
                 reason: "field schema not found in schema tree".to_string(),
             })?;
-        let kind = get_typedef_kind_loose(field_schema).ok_or_else(|| TypedefError::Offset {
+        let kind = get_typedef_kind_loose_enum(field_schema).ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: "field schema has no TypeDef:* kind".to_string(),
         })?;
         let endian = self.endian;
         match kind {
-            "TypeDef:Int8" => {
+            TypeDefKind::Int8 => {
                 let v = data_access::read_i8(buffer, range.start, field_path)?;
                 Ok(FieldValue::I8(v))
             }
-            "TypeDef:Int16" => {
+            TypeDefKind::Int16 => {
                 let v = data_access::read_i16(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::I16(v))
             }
-            "TypeDef:Int32" => {
+            TypeDefKind::Int32 => {
                 let v = data_access::read_i32(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::I32(v))
             }
-            "TypeDef:Uint8" => {
+            TypeDefKind::Uint8 => {
                 let v = data_access::read_u8(buffer, range.start, field_path)?;
                 Ok(FieldValue::U8(v))
             }
-            "TypeDef:Uint16" => {
+            TypeDefKind::Uint16 => {
                 let v = data_access::read_u16(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::U16(v))
             }
-            "TypeDef:Uint32" => {
+            TypeDefKind::Uint32 => {
                 let v = data_access::read_u32(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::U32(v))
             }
-            "TypeDef:Uint64" => {
+            TypeDefKind::Uint64 => {
                 let v = data_access::read_u64(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::U64(v))
             }
-            "TypeDef:Float32" => {
+            TypeDefKind::Float32 => {
                 let v = data_access::read_f32(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::F32(v))
             }
-            "TypeDef:Float64" => {
+            TypeDefKind::Float64 => {
                 let v = data_access::read_f64(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::F64(v))
             }
-            "TypeDef:Boolean" => {
+            TypeDefKind::Boolean => {
                 let v = data_access::read_bool(buffer, range.start, field_path)?;
                 Ok(FieldValue::Bool(v))
             }
-            "TypeDef:Enum" => {
+            TypeDefKind::Enum => {
                 let v = data_access::read_enum(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::Enum(v))
             }
-            "TypeDef:String" => {
+            TypeDefKind::String => {
                 let v = data_access::read_string(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::String(v))
             }
-            "TypeDef:Bytes" => {
+            TypeDefKind::Bytes => {
                 let v = data_access::read_bytes(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::Bytes(v))
             }
-            "TypeDef:Timestamp" => {
+            TypeDefKind::Timestamp => {
                 let v = data_access::read_string(buffer, range.start, field_path, endian)?;
                 Ok(FieldValue::String(v))
             }
-            "TypeDef:Struct" => Ok(FieldValue::Struct {
+            TypeDefKind::Struct => Ok(FieldValue::Struct {
                 start: range.start,
                 end: range.end,
             }),
-            "TypeDef:Union" | "TypeDef:Array" | "TypeDef:Record" => Err(TypedefError::Access {
+            TypeDefKind::Union | TypeDefKind::Array | TypeDefKind::Record => {
+                Err(TypedefError::Access {
                     field_path: field_path.to_string(),
                     reason: "read_field does not support composite types; \
                               use the layout-specific APIs"
                         .to_string(),
-            }),
-            other => Err(TypedefError::Access {
-                field_path: field_path.to_string(),
-                reason: format!("unsupported TypeDef kind for read_field: {other}"),
-            }),
+                })
+            }
         }
     }
 
@@ -737,6 +735,9 @@ mod tests {
     #[test]
     fn typedef_kind_loose_recognizes_object_form() {
         let node = json!({ "TypeDef:String": { "encoding": "offset-indirect" } });
-        assert_eq!(get_typedef_kind_loose(&node), Some("TypeDef:String"));
+        assert_eq!(
+            get_typedef_kind_loose_enum(&node),
+            Some(TypeDefKind::String)
+        );
     }
 }

crates/alknet-typedef/src/layout_builder.rs

@@ -46,7 +46,7 @@
 //!   the variant struct.
 
 use crate::error::TypedefError;
-use crate::schema::{self, get_typedef_kind_loose, resolve_ref_or_inline, DiscriminatorKind, Endian, DISCRIMINATOR_PATH, U32_SIZE};
+use crate::schema::{self, get_typedef_kind_loose_enum, resolve_ref_or_inline, DiscriminatorKind, Endian, TypeDefKind, DISCRIMINATOR_PATH, U32_SIZE};
 use serde_json::Value;
 use std::collections::HashMap;
 
@@ -60,9 +60,8 @@ pub struct FieldPosition {
     /// Byte size of the field (4 for length prefix of variable-length
     /// fields, actual size for fixed-size fields).
     pub size: usize,
-    /// The TypeDef kind of the field (e.g., "TypeDef:Uint32",
-    /// "TypeDef:String").
-    pub kind: String,
+    /// The TypeDef kind of the field.
+    pub kind: TypeDefKind,
 }
 
 /// The result of building a layout: a map of field_path → FieldPosition
@@ -148,10 +147,12 @@ impl LayoutBuilder {
     /// Returns [`TypedefError::Schema`] if the schema has no
     /// `TypeDef:*` kind or the top-level kind is not `TypeDef:Struct`.
     pub fn new(schema: &Value) -> Result<Self, TypedefError> {
-        let kind = schema::get_typedef_kind(schema).ok_or_else(|| {
+        let kind = schema::get_typedef_kind(schema)
+            .and_then(|s| s.parse::<TypeDefKind>().ok())
+            .ok_or_else(|| {
                 TypedefError::Schema("top-level schema has no TypeDef:* kind".to_string())
             })?;
-        if kind != "TypeDef:Struct" {
+        if kind != TypeDefKind::Struct {
             return Err(TypedefError::Schema(format!(
                 "LayoutBuilder requires a TypeDef:Struct at the top level, got {kind}"
             )));
@@ -251,22 +252,25 @@ impl<'a> BuildCtx<'a> {
         field_path: &str,
         offset: &mut usize,
     ) -> Result<(), TypedefError> {
-        let kind = get_typedef_kind_loose(field_schema).ok_or_else(|| TypedefError::Offset {
+        let kind = get_typedef_kind_loose_enum(field_schema).ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: "field schema has no TypeDef:* kind".to_string(),
         })?;
 
         match kind {
-            "TypeDef:Struct" => self.walk_struct(field_schema, field_path, offset),
-            "TypeDef:Union" => self.walk_union(field_schema, field_path, offset),
-            "TypeDef:Array" => self.walk_array(field_schema, field_path, offset),
-            "TypeDef:String" | "TypeDef:Bytes" | "TypeDef:Timestamp" | "TypeDef:Record" => {
+            TypeDefKind::Struct => self.walk_struct(field_schema, field_path, offset),
+            TypeDefKind::Union => self.walk_union(field_schema, field_path, offset),
+            TypeDefKind::Array => self.walk_array(field_schema, field_path, offset),
+            TypeDefKind::String
+            | TypeDefKind::Bytes
+            | TypeDefKind::Timestamp
+            | TypeDefKind::Record => {
                 self.walk_variable(field_path, offset, kind)
             }
-            fixed if schema::is_fixed_size(fixed) => {
-                let size = schema::type_size(fixed).ok_or_else(|| TypedefError::Offset {
+            k if k.is_fixed_size() => {
+                let size = k.type_size().ok_or_else(|| TypedefError::Offset {
                     field_path: field_path.to_string(),
-                    reason: format!("type_size returned None for fixed kind {fixed}"),
+                    reason: format!("type_size returned None for fixed kind {k}"),
                 })?;
                 let start = *offset;
                 *offset = start
@@ -275,13 +279,10 @@ impl<'a> BuildCtx<'a> {
                         field_path: field_path.to_string(),
                         reason: format!("offset {start} + size {size} overflows usize"),
                     })?;
-                self.push(field_path, start, size, fixed);
+                self.push(field_path, start, size, k);
                 Ok(())
             }
-            other => Err(TypedefError::Offset {
-                field_path: field_path.to_string(),
-                reason: format!("unsupported TypeDef kind for packed layout: {other}"),
-            }),
+            _ => unreachable!("all TypeDefKind variants are covered above"),
         }
     }
 
@@ -291,7 +292,7 @@ impl<'a> BuildCtx<'a> {
         &mut self,
         field_path: &str,
         offset: &mut usize,
-        kind: &str,
+        kind: TypeDefKind,
     ) -> Result<(), TypedefError> {
         let data_size =
             self.var_sizes
@@ -341,12 +342,12 @@ impl<'a> BuildCtx<'a> {
                 field_path: field_path.to_string(),
                 reason: "could not resolve TArray items schema".to_string(),
             })?;
-        let elem_kind = get_typedef_kind_loose(element_schema).ok_or_else(|| TypedefError::Offset {
+        let elem_kind = get_typedef_kind_loose_enum(element_schema).ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: "TArray element schema has no TypeDef:* kind".to_string(),
         })?;
 
-        if !schema::is_fixed_size(elem_kind) {
+        if !elem_kind.is_fixed_size() {
             return Err(TypedefError::Offset {
                 field_path: field_path.to_string(),
                 reason: format!(
@@ -355,7 +356,7 @@ impl<'a> BuildCtx<'a> {
             });
         }
 
-        let elem_size = schema::type_size(elem_kind).ok_or_else(|| TypedefError::Offset {
+        let elem_size = elem_kind.type_size().ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: format!("element kind {elem_kind} has no fixed size"),
         })?;
@@ -434,7 +435,7 @@ impl<'a> BuildCtx<'a> {
                     field_path: field_path.to_string(),
                     reason: format!("offset {start} + total {total} overflows usize"),
                 })?;
-            self.push(field_path, start, U32_SIZE, "TypeDef:Array");
+            self.push(field_path, start, U32_SIZE, TypeDefKind::Array);
             Ok(())
         }
     }
@@ -461,7 +462,7 @@ impl<'a> BuildCtx<'a> {
                 offset: disc_off,
                 disc_type,
             } => self
-                .walk_byte_discriminator_union(field_path, offset, &disc_type, disc_off, mapping),
+                .walk_byte_discriminator_union(field_path, offset, disc_type, disc_off, mapping),
             DiscriminatorKind::Field { name: _ } => {
                 self.walk_field_discriminator_union(field_path, offset, mapping)
             }
@@ -473,11 +474,11 @@ impl<'a> BuildCtx<'a> {
         &mut self,
         field_path: &str,
         offset: &mut usize,
-        disc_type: &str,
+        disc_type: TypeDefKind,
         disc_off: usize,
         mapping: &serde_json::Map<String, Value>,
     ) -> Result<(), TypedefError> {
-        let disc_size = schema::type_size(disc_type).ok_or_else(|| TypedefError::Offset {
+        let disc_size = disc_type.type_size().ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: format!("discriminator type {disc_type} has no fixed size"),
         })?;
@@ -517,11 +518,11 @@ impl<'a> BuildCtx<'a> {
                 reason: "could not resolve TUnion variant schema ($ref not found)".to_string(),
             }
         })?;
-        let v_kind = get_typedef_kind_loose(resolved).ok_or_else(|| TypedefError::Offset {
+        let v_kind = get_typedef_kind_loose_enum(resolved).ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: "TUnion variant schema has no TypeDef:* kind".to_string(),
         })?;
-        if v_kind != "TypeDef:Struct" {
+        if v_kind != TypeDefKind::Struct {
             return Err(TypedefError::Offset {
                 field_path: field_path.to_string(),
                 reason: format!("TUnion variant must be TypeDef:Struct, got {v_kind}"),
@@ -580,11 +581,11 @@ impl<'a> BuildCtx<'a> {
                 reason: "could not resolve TUnion variant schema ($ref not found)".to_string(),
             }
         })?;
-        let v_kind = get_typedef_kind_loose(resolved).ok_or_else(|| TypedefError::Offset {
+        let v_kind = get_typedef_kind_loose_enum(resolved).ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: "TUnion variant schema has no TypeDef:* kind".to_string(),
         })?;
-        if v_kind != "TypeDef:Struct" {
+        if v_kind != TypeDefKind::Struct {
             return Err(TypedefError::Offset {
                 field_path: field_path.to_string(),
                 reason: format!("TUnion variant must be TypeDef:Struct, got {v_kind}"),
@@ -595,13 +596,13 @@ impl<'a> BuildCtx<'a> {
     }
 
     /// Push a `(field_path, FieldPosition)` pair onto the fields vec.
-    fn push(&mut self, path: &str, offset: usize, size: usize, kind: &str) {
+    fn push(&mut self, path: &str, offset: usize, size: usize, kind: TypeDefKind) {
         self.fields.push((
             path.to_string(),
             FieldPosition {
                 offset,
                 size,
-                kind: kind.to_string(),
+                kind,
             },
         ));
     }
@@ -639,7 +640,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -647,7 +648,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(
@@ -655,7 +656,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 5,
                 size: 2,
-                kind: "TypeDef:Uint16".into()
+                kind: TypeDefKind::Uint16
             })
         );
         assert_eq!(layout.total_size(), 7);
@@ -677,7 +678,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -685,7 +686,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(
@@ -693,7 +694,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 5,
                 size: 4,
-                kind: "TypeDef:String".into()
+                kind: TypeDefKind::String
             })
         );
         assert_eq!(layout.total_size(), 19);
@@ -714,7 +715,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:String".into()
+                kind: TypeDefKind::String
             })
         );
         assert_eq!(
@@ -722,7 +723,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 9,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(layout.total_size(), 10);
@@ -742,7 +743,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:Bytes".into()
+                kind: TypeDefKind::Bytes
             })
         );
         assert_eq!(layout.total_size(), 7);
@@ -762,7 +763,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:Timestamp".into()
+                kind: TypeDefKind::Timestamp
             })
         );
         assert_eq!(layout.total_size(), 24);
@@ -785,7 +786,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:Record".into()
+                kind: TypeDefKind::Record
             })
         );
         assert_eq!(layout.total_size(), 104);
@@ -834,7 +835,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(
@@ -842,7 +843,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 4,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -850,7 +851,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 5,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 9);
@@ -877,7 +878,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -885,7 +886,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 4,
-                kind: "TypeDef:String".into()
+                kind: TypeDefKind::String
             })
         );
         assert_eq!(
@@ -893,7 +894,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 8,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(layout.total_size(), 9);
@@ -918,7 +919,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(
@@ -926,7 +927,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 4,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(
@@ -934,7 +935,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 8,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 12);
@@ -960,7 +961,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -968,7 +969,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 2,
-                kind: "TypeDef:Uint16".into()
+                kind: TypeDefKind::Uint16
             })
         );
         assert_eq!(
@@ -976,7 +977,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 3,
                 size: 2,
-                kind: "TypeDef:Uint16".into()
+                kind: TypeDefKind::Uint16
             })
         );
         assert_eq!(layout.total_size(), 5);
@@ -999,7 +1000,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:Array".into()
+                kind: TypeDefKind::Array
             })
         );
         assert_eq!(layout.total_size(), 16);
@@ -1085,7 +1086,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -1093,7 +1094,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(
@@ -1101,7 +1102,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 5,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 9);
@@ -1150,7 +1151,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -1158,7 +1159,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 9,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 13);
@@ -1198,7 +1199,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -1206,7 +1207,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(
@@ -1214,7 +1215,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 5,
                 size: 4,
-                kind: "TypeDef:String".into()
+                kind: TypeDefKind::String
             })
         );
         assert_eq!(layout.total_size(), 17);
@@ -1323,7 +1324,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -1331,7 +1332,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 5);
@@ -1376,7 +1377,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 5,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 9);
@@ -1554,7 +1555,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 4,
-                kind: "TypeDef:String".into()
+                kind: TypeDefKind::String
             })
         );
         assert_eq!(layout.total_size(), 9);
@@ -1632,7 +1633,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -1640,7 +1641,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 5);
@@ -1680,7 +1681,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 0,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -1688,7 +1689,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 1,
                 size: 1,
-                kind: "TypeDef:Uint8".into()
+                kind: TypeDefKind::Uint8
             })
         );
         assert_eq!(
@@ -1696,7 +1697,7 @@ mod tests {
             Some(&FieldPosition {
                 offset: 2,
                 size: 4,
-                kind: "TypeDef:Uint32".into()
+                kind: TypeDefKind::Uint32
             })
         );
         assert_eq!(layout.total_size(), 6);

crates/alknet-typedef/src/lib.rs

@@ -38,9 +38,9 @@ pub use error::TypedefError;
 pub use layout_builder::{FieldPosition, LayoutBuilder, PackedLayout};
 pub use offset_map::{ByteRange, OffsetMap};
 pub use schema::{
-    get_typedef_kind_loose, normalize_refs, parse_align, parse_discriminator, parse_encoding,
-    parse_endian, parse_max_length, resolve_ref, resolve_ref_or_inline, DiscriminatorKind, Endian,
-    VariableEncoding,
+    get_typedef_kind_loose, get_typedef_kind_loose_enum, normalize_refs, parse_align,
+    parse_discriminator, parse_encoding, parse_endian, parse_max_length, resolve_ref,
+    resolve_ref_or_inline, DiscriminatorKind, Endian, TypeDefKind, VariableEncoding,
 };
 pub use sequential_reader::{FieldValue, SequentialReader};
 pub use tunion::UnionDispatch;

crates/alknet-typedef/src/macros.rs

@@ -1,8 +1,8 @@
 //! Macros for generating repetitive code across the 17 TypeDef kinds.
 //!
-//! These macros eliminate boilerplate in validation and data access.
-//! Each macro takes a compact specification and generates the full
-//! implementation, ensuring consistency across all types.
+//! These macros eliminate boilerplate in validation, data access, and
+//! dispatch. Each macro takes a compact specification and generates the
+//! full implementation, ensuring consistency across all types.
 
 // ---------------------------------------------------------------------------
 // Validation macros

crates/alknet-typedef/src/offset_map.rs

@@ -13,9 +13,9 @@
 
 use crate::error::TypedefError;
 use crate::schema::{
-    get_typedef_kind, get_typedef_kind_loose, is_fixed_size, natural_alignment, parse_align,
-    parse_discriminator, parse_encoding, parse_max_length, resolve_ref_or_inline, type_size,
-    DiscriminatorKind, VariableEncoding, DISCRIMINATOR_PATH,
+    get_typedef_kind, get_typedef_kind_loose_enum, parse_align, parse_discriminator, parse_encoding,
+    parse_max_length, resolve_ref_or_inline, DiscriminatorKind, TypeDefKind, VariableEncoding,
+    DISCRIMINATOR_PATH,
 };
 use serde_json::Value;
 
@@ -79,10 +79,12 @@ impl OffsetMap {
     /// Returns [`TypedefError::Offset`] for unsupported type combinations
     /// encountered during the walk.
     pub fn compute(schema: &Value) -> Result<Self, TypedefError> {
-        let kind = get_typedef_kind(schema).ok_or_else(|| {
+        let kind = get_typedef_kind(schema)
+            .and_then(|s| s.parse::<TypeDefKind>().ok())
+            .ok_or_else(|| {
                 TypedefError::Schema("top-level schema has no TypeDef:* kind".to_string())
             })?;
-        if kind != "TypeDef:Struct" {
+        if kind != TypeDefKind::Struct {
             return Err(TypedefError::Schema(format!(
                 "OffsetMap::compute requires a TypeDef:Struct at the top level, got {kind}"
             )));
@@ -207,47 +209,47 @@ impl<'a> ComputeCtx<'a> {
         field_path: &str,
         struct_default_align: usize,
     ) -> Result<FieldLayout, TypedefError> {
-        let kind = get_typedef_kind_loose(field_schema).ok_or_else(|| TypedefError::Offset {
+        let kind = get_typedef_kind_loose_enum(field_schema).ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: "field schema has no TypeDef:* kind".to_string(),
         })?;
 
         match kind {
-            "TypeDef:Struct" => {
+            TypeDefKind::Struct => {
                 self.compute_struct_field(field_schema, field_path, struct_default_align)
             }
-            "TypeDef:Union" => {
+            TypeDefKind::Union => {
                 self.compute_union_field(field_schema, field_path, struct_default_align)
             }
-            "TypeDef:Array" => {
+            TypeDefKind::Array => {
                 self.compute_array_field(field_schema, field_path, struct_default_align)
             }
-            "TypeDef:String" | "TypeDef:Bytes" | "TypeDef:Record" | "TypeDef:Timestamp" => {
+            TypeDefKind::String
+            | TypeDefKind::Bytes
+            | TypeDefKind::Record
+            | TypeDefKind::Timestamp => {
                 self.compute_variable_field(field_schema, field_path, struct_default_align)
             }
-            fixed if is_fixed_size(fixed) => {
-                self.compute_fixed_field(fixed, field_schema, field_path, struct_default_align)
+            k if k.is_fixed_size() => {
+                self.compute_fixed_field(k, field_schema, field_path, struct_default_align)
             }
-            other => Err(TypedefError::Offset {
-                field_path: field_path.to_string(),
-                reason: format!("unsupported TypeDef kind for offset computation: {other}"),
-            }),
+            _ => unreachable!("all TypeDefKind variants are covered above"),
         }
     }
 
     /// Compute the layout for a fixed-size primitive field.
     fn compute_fixed_field(
         &mut self,
-        kind: &str,
+        kind: TypeDefKind,
         field_schema: &Value,
         field_path: &str,
         struct_default_align: usize,
     ) -> Result<FieldLayout, TypedefError> {
-        let size = type_size(kind).ok_or_else(|| TypedefError::Offset {
+        let size = kind.type_size().ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: format!("type_size returned None for fixed kind {kind}"),
         })?;
-        let natural = natural_alignment(kind);
+        let natural = kind.natural_alignment();
         let align = field_alignment(field_schema, struct_default_align, natural);
         align_up(&mut self.offset, align);
         let start = self.offset;
@@ -318,11 +320,11 @@ impl<'a> ComputeCtx<'a> {
                 offset: disc_off,
                 disc_type,
             } => {
-                let disc_size = type_size(&disc_type).ok_or_else(|| TypedefError::Offset {
+                let disc_size = disc_type.type_size().ok_or_else(|| TypedefError::Offset {
                     field_path: field_path.to_string(),
                     reason: format!("discriminator type {disc_type} has no fixed size"),
                 })?;
-                let disc_natural = natural_alignment(&disc_type);
+                let disc_natural = disc_type.natural_alignment();
                 let disc_align = union_default_align.max(disc_natural);
                 align_up(&mut self.offset, disc_align);
                 let union_start = self.offset;
@@ -378,11 +380,13 @@ impl<'a> ComputeCtx<'a> {
                     reason: "could not resolve TUnion variant schema ($ref not found)".to_string(),
                 }
             })?;
-            let v_kind = get_typedef_kind(resolved).ok_or_else(|| TypedefError::Offset {
+            let v_kind = get_typedef_kind(resolved)
+                .and_then(|s| s.parse::<TypeDefKind>().ok())
+                .ok_or_else(|| TypedefError::Offset {
                     field_path: field_path.to_string(),
                     reason: "TUnion variant schema has no TypeDef:* kind".to_string(),
                 })?;
-            if v_kind != "TypeDef:Struct" {
+            if v_kind != TypeDefKind::Struct {
                 return Err(TypedefError::Offset {
                     field_path: field_path.to_string(),
                     reason: format!("TUnion variant must be TypeDef:Struct, got {v_kind}"),
@@ -416,11 +420,13 @@ impl<'a> ComputeCtx<'a> {
             let Some(resolved) = resolve_ref_or_inline(variant_schema, self.root) else {
                 continue;
             };
-            let v_kind = get_typedef_kind(resolved).ok_or_else(|| TypedefError::Offset {
+            let v_kind = get_typedef_kind(resolved)
+                .and_then(|s| s.parse::<TypeDefKind>().ok())
+                .ok_or_else(|| TypedefError::Offset {
                     field_path: field_path.to_string(),
                     reason: "TUnion variant schema has no TypeDef:* kind".to_string(),
                 })?;
-            if v_kind != "TypeDef:Struct" {
+            if v_kind != TypeDefKind::Struct {
                 return Err(TypedefError::Offset {
                     field_path: field_path.to_string(),
                     reason: format!("TUnion variant must be TypeDef:Struct, got {v_kind}"),
@@ -468,11 +474,13 @@ impl<'a> ComputeCtx<'a> {
                 field_path: field_path.to_string(),
                 reason: "could not resolve TArray items schema".to_string(),
             })?;
-        let elem_kind = get_typedef_kind(element_schema).ok_or_else(|| TypedefError::Offset {
+        let elem_kind = get_typedef_kind(element_schema)
+            .and_then(|s| s.parse::<TypeDefKind>().ok())
+            .ok_or_else(|| TypedefError::Offset {
                 field_path: field_path.to_string(),
                 reason: "TArray element schema has no TypeDef:* kind".to_string(),
             })?;
-        if !is_fixed_size(elem_kind) {
+        if !elem_kind.is_fixed_size() {
             return Err(TypedefError::Offset {
                 field_path: field_path.to_string(),
                 reason: format!(
@@ -481,11 +489,11 @@ impl<'a> ComputeCtx<'a> {
             });
         }
 
-        let elem_size = type_size(elem_kind).ok_or_else(|| TypedefError::Offset {
+        let elem_size = elem_kind.type_size().ok_or_else(|| TypedefError::Offset {
             field_path: field_path.to_string(),
             reason: format!("element kind {elem_kind} has no fixed size"),
         })?;
-        let elem_natural = natural_alignment(elem_kind);
+        let elem_natural = elem_kind.natural_alignment();
         let elem_align = field_alignment(element_schema, struct_default_align, elem_natural);
         let stride = round_up(elem_size, elem_align);
 

crates/alknet-typedef/src/schema.rs

@@ -10,13 +10,202 @@
 
 use crate::error::TypedefError;
 use serde_json::Value;
+use std::fmt;
+use std::str::FromStr;
 
 const TYPEDEF_PREFIX: &str = "TypeDef:";
 
 pub(crate) const U32_SIZE: usize = 4;
 pub(crate) const DISCRIMINATOR_PATH: &str = "__discriminator";
 
-const BYTE_DISCRIMINATOR_TYPES: &[&str] = &["TypeDef:Uint8", "TypeDef:Uint16", "TypeDef:Uint32"];
+const BYTE_DISCRIMINATOR_TYPES: &[TypeDefKind] = &[
+    TypeDefKind::Uint8,
+    TypeDefKind::Uint16,
+    TypeDefKind::Uint32,
+];
+
+/// The 17 `TypeDef:*` kinds recognized by the engine.
+///
+/// Each variant corresponds to a `TypeDef:<name>` JSON Schema keyword.
+/// The enum provides compile-time exhaustiveness checking and integer
+/// discriminant dispatch (jump table) instead of string comparison.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum TypeDefKind {
+    Int8,
+    Int16,
+    Int32,
+    Uint8,
+    Uint16,
+    Uint32,
+    Uint64,
+    Float32,
+    Float64,
+    Boolean,
+    Enum,
+    String,
+    Bytes,
+    Struct,
+    Union,
+    Array,
+    Record,
+    Timestamp,
+}
+
+impl TypeDefKind {
+    /// The JSON Schema keyword string, e.g. `"TypeDef:Int8"`.
+    pub fn as_str(self) -> &'static str {
+        match self {
+            TypeDefKind::Int8 => "TypeDef:Int8",
+            TypeDefKind::Int16 => "TypeDef:Int16",
+            TypeDefKind::Int32 => "TypeDef:Int32",
+            TypeDefKind::Uint8 => "TypeDef:Uint8",
+            TypeDefKind::Uint16 => "TypeDef:Uint16",
+            TypeDefKind::Uint32 => "TypeDef:Uint32",
+            TypeDefKind::Uint64 => "TypeDef:Uint64",
+            TypeDefKind::Float32 => "TypeDef:Float32",
+            TypeDefKind::Float64 => "TypeDef:Float64",
+            TypeDefKind::Boolean => "TypeDef:Boolean",
+            TypeDefKind::Enum => "TypeDef:Enum",
+            TypeDefKind::String => "TypeDef:String",
+            TypeDefKind::Bytes => "TypeDef:Bytes",
+            TypeDefKind::Struct => "TypeDef:Struct",
+            TypeDefKind::Union => "TypeDef:Union",
+            TypeDefKind::Array => "TypeDef:Array",
+            TypeDefKind::Record => "TypeDef:Record",
+            TypeDefKind::Timestamp => "TypeDef:Timestamp",
+        }
+    }
+
+    /// Fixed byte size, or `None` for variable-size / composite kinds.
+    pub fn type_size(self) -> Option<usize> {
+        match self {
+            TypeDefKind::Float32 | TypeDefKind::Int32 | TypeDefKind::Uint32 | TypeDefKind::Enum => {
+                Some(4)
+            }
+            TypeDefKind::Float64 => Some(8),
+            TypeDefKind::Int8 | TypeDefKind::Uint8 | TypeDefKind::Boolean => Some(1),
+            TypeDefKind::Int16 | TypeDefKind::Uint16 => Some(2),
+            TypeDefKind::String
+            | TypeDefKind::Bytes
+            | TypeDefKind::Struct
+            | TypeDefKind::Union
+            | TypeDefKind::Array
+            | TypeDefKind::Record
+            | TypeDefKind::Timestamp
+            | TypeDefKind::Uint64 => None,
+        }
+    }
+
+    /// Natural alignment: 1 for u8/i8/bool, 2 for u16/i16, 4 for u32/i32/f32/enum,
+    /// 8 for f64, 4 for variable-length (u32 length prefix), 1 for composites.
+    pub fn natural_alignment(self) -> usize {
+        match self {
+            TypeDefKind::Int8 | TypeDefKind::Uint8 | TypeDefKind::Boolean => 1,
+            TypeDefKind::Int16 | TypeDefKind::Uint16 => 2,
+            TypeDefKind::Int32
+            | TypeDefKind::Uint32
+            | TypeDefKind::Float32
+            | TypeDefKind::Enum => 4,
+            TypeDefKind::Float64 => 8,
+            TypeDefKind::String
+            | TypeDefKind::Bytes
+            | TypeDefKind::Record
+            | TypeDefKind::Timestamp => 4,
+            TypeDefKind::Struct | TypeDefKind::Union | TypeDefKind::Array => 1,
+            TypeDefKind::Uint64 => 8,
+        }
+    }
+
+    /// Returns `true` for fixed-size primitive kinds.
+    pub fn is_fixed_size(self) -> bool {
+        matches!(
+            self,
+            TypeDefKind::Float32
+                | TypeDefKind::Float64
+                | TypeDefKind::Int8
+                | TypeDefKind::Int16
+                | TypeDefKind::Int32
+                | TypeDefKind::Uint8
+                | TypeDefKind::Uint16
+                | TypeDefKind::Uint32
+                | TypeDefKind::Boolean
+                | TypeDefKind::Enum
+        )
+    }
+
+    /// Returns `true` for kinds whose read/write functions need an `Endian` parameter.
+    pub fn needs_endian(self) -> bool {
+        matches!(
+            self,
+            TypeDefKind::Int16
+                | TypeDefKind::Int32
+                | TypeDefKind::Uint16
+                | TypeDefKind::Uint32
+                | TypeDefKind::Uint64
+                | TypeDefKind::Float32
+                | TypeDefKind::Float64
+                | TypeDefKind::Enum
+                | TypeDefKind::String
+                | TypeDefKind::Bytes
+                | TypeDefKind::Timestamp
+        )
+    }
+
+    /// Returns `true` for composite kinds (Struct, Union, Array, Record).
+    pub fn is_composite(self) -> bool {
+        matches!(
+            self,
+            TypeDefKind::Struct | TypeDefKind::Union | TypeDefKind::Array | TypeDefKind::Record
+        )
+    }
+
+    /// Returns `true` for variable-length kinds (String, Bytes, Timestamp, Record).
+    pub fn is_variable_length(self) -> bool {
+        matches!(
+            self,
+            TypeDefKind::String
+                | TypeDefKind::Bytes
+                | TypeDefKind::Timestamp
+                | TypeDefKind::Record
+        )
+    }
+}
+
+impl fmt::Display for TypeDefKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+impl FromStr for TypeDefKind {
+    type Err = TypedefError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "TypeDef:Int8" => Ok(TypeDefKind::Int8),
+            "TypeDef:Int16" => Ok(TypeDefKind::Int16),
+            "TypeDef:Int32" => Ok(TypeDefKind::Int32),
+            "TypeDef:Uint8" => Ok(TypeDefKind::Uint8),
+            "TypeDef:Uint16" => Ok(TypeDefKind::Uint16),
+            "TypeDef:Uint32" => Ok(TypeDefKind::Uint32),
+            "TypeDef:Uint64" => Ok(TypeDefKind::Uint64),
+            "TypeDef:Float32" => Ok(TypeDefKind::Float32),
+            "TypeDef:Float64" => Ok(TypeDefKind::Float64),
+            "TypeDef:Boolean" => Ok(TypeDefKind::Boolean),
+            "TypeDef:Enum" => Ok(TypeDefKind::Enum),
+            "TypeDef:String" => Ok(TypeDefKind::String),
+            "TypeDef:Bytes" => Ok(TypeDefKind::Bytes),
+            "TypeDef:Struct" => Ok(TypeDefKind::Struct),
+            "TypeDef:Union" => Ok(TypeDefKind::Union),
+            "TypeDef:Array" => Ok(TypeDefKind::Array),
+            "TypeDef:Record" => Ok(TypeDefKind::Record),
+            "TypeDef:Timestamp" => Ok(TypeDefKind::Timestamp),
+            other => Err(TypedefError::Schema(format!(
+                "unknown TypeDef kind: {other}"
+            ))),
+        }
+    }
+}
 
 /// Returns the `TypeDef:*` kind string if the schema node declares one.
 /// Returns `None` if the node has no `TypeDef:*` keyword.
@@ -35,58 +224,10 @@ pub fn get_typedef_kind(node: &Value) -> Option<&str> {
     None
 }
 
-/// Returns the fixed byte size for a TypeDef kind, or `None` if variable-size
-/// or composite (Struct/Union/Array/Record).
-///
-/// Only the 17 alknet-typedef kinds are recognized. `TypeDef:Int64` and
-/// `TypeDef:Uint64` are NOT among the 17 kinds (TypeBox defines them but
-/// alknet-typedef omits them), so they return `None` here.
-pub fn type_size(kind: &str) -> Option<usize> {
-    match kind {
-        "TypeDef:Float32" | "TypeDef:Int32" | "TypeDef:Uint32" | "TypeDef:Enum" => Some(4),
-        "TypeDef:Float64" => Some(8),
-        "TypeDef:Int8" | "TypeDef:Uint8" | "TypeDef:Boolean" => Some(1),
-        "TypeDef:Int16" | "TypeDef:Uint16" => Some(2),
-        "TypeDef:String" | "TypeDef:Bytes" | "TypeDef:Struct" | "TypeDef:Union"
-        | "TypeDef:Array" | "TypeDef:Record" | "TypeDef:Timestamp" => None,
-        _ => None,
-    }
-}
-
-/// Returns the natural alignment for a TypeDef kind.
-///
-/// Default alignment: 1 for u8/i8/bool, 2 for u16/i16, 4 for u32/i32/f32/enum,
-/// 8 for u64/i64/f64. Variable-length types (String/Bytes/Record/Timestamp)
-/// align to 4 (the length prefix is u32). Composite types (Struct/Union/Array)
-/// return 1 here — their alignment is computed from their fields during
-/// offset computation.
-pub fn natural_alignment(kind: &str) -> usize {
-    match kind {
-        "TypeDef:Int8" | "TypeDef:Uint8" | "TypeDef:Boolean" => 1,
-        "TypeDef:Int16" | "TypeDef:Uint16" => 2,
-        "TypeDef:Int32" | "TypeDef:Uint32" | "TypeDef:Float32" | "TypeDef:Enum" => 4,
-        "TypeDef:Float64" => 8,
-        "TypeDef:String" | "TypeDef:Bytes" | "TypeDef:Record" | "TypeDef:Timestamp" => 4,
-        "TypeDef:Struct" | "TypeDef:Union" | "TypeDef:Array" => 1,
-        _ => 1,
-    }
-}
-
-/// Returns true if the kind is a fixed-size type (known byte size at schema time).
-pub fn is_fixed_size(kind: &str) -> bool {
-    matches!(
-        kind,
-        "TypeDef:Float32"
-            | "TypeDef:Float64"
-            | "TypeDef:Int8"
-            | "TypeDef:Int16"
-            | "TypeDef:Int32"
-            | "TypeDef:Uint8"
-            | "TypeDef:Uint16"
-            | "TypeDef:Uint32"
-            | "TypeDef:Boolean"
-            | "TypeDef:Enum"
-    )
+/// Returns the `TypeDefKind` enum variant if the schema node declares one
+/// (boolean form only, like `get_typedef_kind`).
+pub fn get_typedef_kind_enum(node: &Value) -> Option<TypeDefKind> {
+    get_typedef_kind(node).and_then(|s| s.parse().ok())
 }
 
 /// Byte endianness for multi-byte integer and float fields.
@@ -172,7 +313,7 @@ pub enum DiscriminatorKind {
         offset: usize,
         /// The `TypeDef:*` kind of the discriminator (typically
         /// `TypeDef:Uint8`).
-        disc_type: String,
+        disc_type: TypeDefKind,
     },
     /// Field-name discriminator: a named field within the struct. Mapping keys
     /// are string values matching the discriminator field's value. The
@@ -204,17 +345,24 @@ pub fn parse_discriminator(node: &Value) -> Result<DiscriminatorKind, TypedefErr
     match kind {
         "byte" => {
             let offset = disc_obj.get("offset").and_then(Value::as_u64).unwrap_or(0) as usize;
-            let disc_type = disc_obj
+            let disc_type_str = disc_obj
                 .get("type")
                 .and_then(Value::as_str)
-                .unwrap_or("TypeDef:Uint8")
-                .to_string();
-            if !BYTE_DISCRIMINATOR_TYPES.contains(&disc_type.as_str()) {
+                .unwrap_or("TypeDef:Uint8");
+            let disc_type: TypeDefKind = disc_type_str.parse().map_err(|_| {
+                TypedefError::Schema(format!(
+                    "discriminator 'type' must be one of {BYTE_DISCRIMINATOR_TYPES:?}, got {disc_type_str:?}"
+                ))
+            })?;
+            if !BYTE_DISCRIMINATOR_TYPES.contains(&disc_type) {
                 return Err(TypedefError::Schema(format!(
                     "discriminator 'type' must be one of {BYTE_DISCRIMINATOR_TYPES:?}, got {disc_type:?}"
                 )));
             }
-            Ok(DiscriminatorKind::Byte { offset, disc_type })
+            Ok(DiscriminatorKind::Byte {
+                offset,
+                disc_type,
+            })
         }
         "field" => {
             let name = disc_obj
@@ -251,6 +399,11 @@ pub fn get_typedef_kind_loose(node: &Value) -> Option<&str> {
     None
 }
 
+/// Like [`get_typedef_kind_loose`] but returns the parsed [`TypeDefKind`] enum.
+pub fn get_typedef_kind_loose_enum(node: &Value) -> Option<TypeDefKind> {
+    get_typedef_kind_loose(node).and_then(|s| s.parse().ok())
+}
+
 /// Resolve a `$ref` against the root schema, or return the inline schema.
 ///
 /// If `node` has a `"$ref"` key, parse the JSON Pointer and walk `root`.
@@ -334,87 +487,87 @@ mod tests {
 
     #[test]
     fn type_size_fixed_kinds() {
-        assert_eq!(type_size("TypeDef:Float32"), Some(4));
-        assert_eq!(type_size("TypeDef:Float64"), Some(8));
-        assert_eq!(type_size("TypeDef:Int8"), Some(1));
-        assert_eq!(type_size("TypeDef:Int16"), Some(2));
-        assert_eq!(type_size("TypeDef:Int32"), Some(4));
-        assert_eq!(type_size("TypeDef:Uint8"), Some(1));
-        assert_eq!(type_size("TypeDef:Uint16"), Some(2));
-        assert_eq!(type_size("TypeDef:Uint32"), Some(4));
-        assert_eq!(type_size("TypeDef:Boolean"), Some(1));
-        assert_eq!(type_size("TypeDef:Enum"), Some(4));
+        assert_eq!(TypeDefKind::Float32.type_size(), Some(4));
+        assert_eq!(TypeDefKind::Float64.type_size(), Some(8));
+        assert_eq!(TypeDefKind::Int8.type_size(), Some(1));
+        assert_eq!(TypeDefKind::Int16.type_size(), Some(2));
+        assert_eq!(TypeDefKind::Int32.type_size(), Some(4));
+        assert_eq!(TypeDefKind::Uint8.type_size(), Some(1));
+        assert_eq!(TypeDefKind::Uint16.type_size(), Some(2));
+        assert_eq!(TypeDefKind::Uint32.type_size(), Some(4));
+        assert_eq!(TypeDefKind::Boolean.type_size(), Some(1));
+        assert_eq!(TypeDefKind::Enum.type_size(), Some(4));
     }
 
     #[test]
     fn type_size_variable_and_composite_kinds() {
         for kind in [
-            "TypeDef:String",
-            "TypeDef:Bytes",
-            "TypeDef:Struct",
-            "TypeDef:Union",
-            "TypeDef:Array",
-            "TypeDef:Record",
-            "TypeDef:Timestamp",
+            TypeDefKind::String,
+            TypeDefKind::Bytes,
+            TypeDefKind::Struct,
+            TypeDefKind::Union,
+            TypeDefKind::Array,
+            TypeDefKind::Record,
+            TypeDefKind::Timestamp,
         ] {
-            assert_eq!(type_size(kind), None, "failed for {kind}");
+            assert_eq!(kind.type_size(), None, "failed for {kind}");
         }
     }
 
     #[test]
     fn type_size_unknown_kind_returns_none() {
-        assert_eq!(type_size("TypeDef:Int64"), None);
-        assert_eq!(type_size("TypeDef:Uint64"), None);
-        assert_eq!(type_size("not-a-typedef"), None);
+        assert!("TypeDef:Int64".parse::<TypeDefKind>().is_err());
+        assert!("TypeDef:Uint128".parse::<TypeDefKind>().is_err());
+        assert!("not-a-typedef".parse::<TypeDefKind>().is_err());
     }
 
     #[test]
     fn natural_alignment_matches_spec() {
-        assert_eq!(natural_alignment("TypeDef:Int8"), 1);
-        assert_eq!(natural_alignment("TypeDef:Uint8"), 1);
-        assert_eq!(natural_alignment("TypeDef:Boolean"), 1);
-        assert_eq!(natural_alignment("TypeDef:Int16"), 2);
-        assert_eq!(natural_alignment("TypeDef:Uint16"), 2);
-        assert_eq!(natural_alignment("TypeDef:Int32"), 4);
-        assert_eq!(natural_alignment("TypeDef:Uint32"), 4);
-        assert_eq!(natural_alignment("TypeDef:Float32"), 4);
-        assert_eq!(natural_alignment("TypeDef:Enum"), 4);
-        assert_eq!(natural_alignment("TypeDef:Float64"), 8);
-        assert_eq!(natural_alignment("TypeDef:String"), 4);
-        assert_eq!(natural_alignment("TypeDef:Bytes"), 4);
-        assert_eq!(natural_alignment("TypeDef:Record"), 4);
-        assert_eq!(natural_alignment("TypeDef:Timestamp"), 4);
-        assert_eq!(natural_alignment("TypeDef:Struct"), 1);
-        assert_eq!(natural_alignment("TypeDef:Union"), 1);
-        assert_eq!(natural_alignment("TypeDef:Array"), 1);
+        assert_eq!(TypeDefKind::Int8.natural_alignment(), 1);
+        assert_eq!(TypeDefKind::Uint8.natural_alignment(), 1);
+        assert_eq!(TypeDefKind::Boolean.natural_alignment(), 1);
+        assert_eq!(TypeDefKind::Int16.natural_alignment(), 2);
+        assert_eq!(TypeDefKind::Uint16.natural_alignment(), 2);
+        assert_eq!(TypeDefKind::Int32.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Uint32.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Float32.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Enum.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Float64.natural_alignment(), 8);
+        assert_eq!(TypeDefKind::String.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Bytes.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Record.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Timestamp.natural_alignment(), 4);
+        assert_eq!(TypeDefKind::Struct.natural_alignment(), 1);
+        assert_eq!(TypeDefKind::Union.natural_alignment(), 1);
+        assert_eq!(TypeDefKind::Array.natural_alignment(), 1);
     }
 
     #[test]
     fn is_fixed_size_classifies_correctly() {
         for kind in [
-            "TypeDef:Float32",
-            "TypeDef:Float64",
-            "TypeDef:Int8",
-            "TypeDef:Int16",
-            "TypeDef:Int32",
-            "TypeDef:Uint8",
-            "TypeDef:Uint16",
-            "TypeDef:Uint32",
-            "TypeDef:Boolean",
-            "TypeDef:Enum",
+            TypeDefKind::Float32,
+            TypeDefKind::Float64,
+            TypeDefKind::Int8,
+            TypeDefKind::Int16,
+            TypeDefKind::Int32,
+            TypeDefKind::Uint8,
+            TypeDefKind::Uint16,
+            TypeDefKind::Uint32,
+            TypeDefKind::Boolean,
+            TypeDefKind::Enum,
         ] {
-            assert!(is_fixed_size(kind), "expected fixed: {kind}");
+            assert!(kind.is_fixed_size(), "expected fixed: {kind}");
         }
         for kind in [
-            "TypeDef:String",
-            "TypeDef:Bytes",
-            "TypeDef:Struct",
-            "TypeDef:Union",
-            "TypeDef:Array",
-            "TypeDef:Record",
-            "TypeDef:Timestamp",
+            TypeDefKind::String,
+            TypeDefKind::Bytes,
+            TypeDefKind::Struct,
+            TypeDefKind::Union,
+            TypeDefKind::Array,
+            TypeDefKind::Record,
+            TypeDefKind::Timestamp,
         ] {
-            assert!(!is_fixed_size(kind), "expected variable: {kind}");
+            assert!(!kind.is_fixed_size(), "expected variable: {kind}");
         }
     }
 
@@ -510,7 +663,7 @@ mod tests {
             disc,
             DiscriminatorKind::Byte {
                 offset: 0,
-                disc_type: "TypeDef:Uint8".to_string(),
+                disc_type: TypeDefKind::Uint8,
             }
         );
     }
@@ -525,7 +678,7 @@ mod tests {
             disc,
             DiscriminatorKind::Byte {
                 offset: 4,
-                disc_type: "TypeDef:Uint16".to_string(),
+                disc_type: TypeDefKind::Uint16,
             }
         );
     }

crates/alknet-typedef/src/sequential_reader.rs

@@ -12,7 +12,7 @@
 
 use crate::data_access;
 use crate::error::TypedefError;
-use crate::schema::{self, get_typedef_kind_loose, DiscriminatorKind, Endian, U32_SIZE};
+use crate::schema::{self, get_typedef_kind_loose_enum, DiscriminatorKind, Endian, TypeDefKind, U32_SIZE};
 use serde_json::Value;
 
 /// A value read from a field during sequential traversal.
@@ -115,8 +115,9 @@ impl SequentialReader {
     /// does not declare `TypeDef:Struct`, or has no `properties` object.
     pub fn new(schema: &Value) -> Result<Self, TypedefError> {
         let kind = schema::get_typedef_kind(schema)
+            .and_then(|s| s.parse::<TypeDefKind>().ok())
             .ok_or_else(|| TypedefError::Schema("schema has no TypeDef:* kind".to_string()))?;
-        if kind != "TypeDef:Struct" {
+        if kind != TypeDefKind::Struct {
             return Err(TypedefError::Schema(format!(
                 "SequentialReader only supports TypeDef:Struct at the top level, got {kind}"
             )));
@@ -272,73 +273,73 @@ fn read_field_value<'a>(
     offset: usize,
     endian: Endian,
 ) -> Result<(FieldValue<'a>, usize), TypedefError> {
-    let kind = get_typedef_kind_loose(field_schema).ok_or_else(|| {
+    let kind = get_typedef_kind_loose_enum(field_schema).ok_or_else(|| {
         TypedefError::Schema(format!(
             "field {field_path} has no TypeDef:* kind: {field_schema}"
         ))
     })?;
 
     match kind {
-        "TypeDef:Int8" => {
+        TypeDefKind::Int8 => {
             let v = data_access::read_i8(buffer, offset, field_path)?;
             Ok((FieldValue::I8(v), offset + 1))
         }
-        "TypeDef:Int16" => {
+        TypeDefKind::Int16 => {
             let v = data_access::read_i16(buffer, offset, field_path, endian)?;
             Ok((FieldValue::I16(v), offset + 2))
         }
-        "TypeDef:Int32" => {
+        TypeDefKind::Int32 => {
             let v = data_access::read_i32(buffer, offset, field_path, endian)?;
             Ok((FieldValue::I32(v), offset + 4))
         }
-        "TypeDef:Uint8" => {
+        TypeDefKind::Uint8 => {
             let v = data_access::read_u8(buffer, offset, field_path)?;
             Ok((FieldValue::U8(v), offset + 1))
         }
-        "TypeDef:Uint16" => {
+        TypeDefKind::Uint16 => {
             let v = data_access::read_u16(buffer, offset, field_path, endian)?;
             Ok((FieldValue::U16(v), offset + 2))
         }
-        "TypeDef:Uint32" => {
+        TypeDefKind::Uint32 => {
             let v = data_access::read_u32(buffer, offset, field_path, endian)?;
             Ok((FieldValue::U32(v), offset + 4))
         }
-        "TypeDef:Uint64" => {
+        TypeDefKind::Uint64 => {
             let v = data_access::read_u64(buffer, offset, field_path, endian)?;
             Ok((FieldValue::U64(v), offset + 8))
         }
-        "TypeDef:Float32" => {
+        TypeDefKind::Float32 => {
             let v = data_access::read_f32(buffer, offset, field_path, endian)?;
             Ok((FieldValue::F32(v), offset + 4))
         }
-        "TypeDef:Float64" => {
+        TypeDefKind::Float64 => {
             let v = data_access::read_f64(buffer, offset, field_path, endian)?;
             Ok((FieldValue::F64(v), offset + 8))
         }
-        "TypeDef:Boolean" => {
+        TypeDefKind::Boolean => {
             let v = data_access::read_bool(buffer, offset, field_path)?;
             Ok((FieldValue::Bool(v), offset + 1))
         }
-        "TypeDef:Enum" => {
+        TypeDefKind::Enum => {
             let v = data_access::read_enum(buffer, offset, field_path, endian)?;
             Ok((FieldValue::Enum(v), offset + 4))
         }
-        "TypeDef:String" => {
+        TypeDefKind::String => {
             let s = data_access::read_string(buffer, offset, field_path, endian)?;
             let total = U32_SIZE + s.len();
             Ok((FieldValue::String(s), offset + total))
         }
-        "TypeDef:Bytes" => {
+        TypeDefKind::Bytes => {
             let b = data_access::read_bytes(buffer, offset, field_path, endian)?;
             let total = U32_SIZE + b.len();
             Ok((FieldValue::Bytes(b), offset + total))
         }
-        "TypeDef:Timestamp" => {
+        TypeDefKind::Timestamp => {
             let s = data_access::read_string(buffer, offset, field_path, endian)?;
             let total = U32_SIZE + s.len();
             Ok((FieldValue::String(s), offset + total))
         }
-        "TypeDef:Struct" => {
+        TypeDefKind::Struct => {
             let size = walk_struct_size(root_schema, field_schema, buffer, offset, endian)?;
             let end = offset
                 .checked_add(size)
@@ -348,7 +349,7 @@ fn read_field_value<'a>(
                 })?;
             Ok((FieldValue::Struct { start: offset, end }, end))
         }
-        "TypeDef:Union" => read_union_value(
+        TypeDefKind::Union => read_union_value(
             buffer,
             root_schema,
             field_schema,
@@ -356,7 +357,7 @@ fn read_field_value<'a>(
             offset,
             endian,
         ),
-        "TypeDef:Array" => read_array_value(
+        TypeDefKind::Array => read_array_value(
             buffer,
             root_schema,
             field_schema,
@@ -364,7 +365,7 @@ fn read_field_value<'a>(
             offset,
             endian,
         ),
-        "TypeDef:Record" => read_record_value(
+        TypeDefKind::Record => read_record_value(
             buffer,
             root_schema,
             field_schema,
@@ -372,9 +373,6 @@ fn read_field_value<'a>(
             offset,
             endian,
         ),
-        other => Err(TypedefError::Schema(format!(
-            "unsupported TypeDef kind for sequential read: {other}"
-        ))),
     }
 }
 
@@ -421,7 +419,7 @@ fn read_union_value<'a>(
                         ),
                     })?;
             let (disc_value, disc_size) =
-                read_byte_discriminator(buffer, abs_offset, field_path, &disc_type, endian)?;
+                read_byte_discriminator(buffer, abs_offset, field_path, disc_type, endian)?;
             let key = disc_value.to_string();
             let variant_schema = mapping.get(&key).ok_or_else(|| TypedefError::Access {
                 field_path: field_path.to_string(),
@@ -514,19 +512,19 @@ fn read_byte_discriminator(
     buffer: &[u8],
     offset: usize,
     field_path: &str,
-    disc_type: &str,
+    disc_type: TypeDefKind,
     endian: Endian,
 ) -> Result<(u32, usize), TypedefError> {
     match disc_type {
-        "TypeDef:Uint8" => {
+        TypeDefKind::Uint8 => {
             let v = data_access::read_u8(buffer, offset, field_path)?;
             Ok((v as u32, 1))
         }
-        "TypeDef:Uint16" => {
+        TypeDefKind::Uint16 => {
             let v = data_access::read_u16(buffer, offset, field_path, endian)?;
             Ok((v as u32, 2))
         }
-        "TypeDef:Uint32" => {
+        TypeDefKind::Uint32 => {
             let v = data_access::read_u32(buffer, offset, field_path, endian)?;
             Ok((v, 4))
         }
@@ -596,14 +594,14 @@ fn read_array_value<'a>(
         (count, offset + U32_SIZE)
     };
 
-    let element_kind = get_typedef_kind_loose(items_schema).ok_or_else(|| {
+    let element_kind = get_typedef_kind_loose_enum(items_schema).ok_or_else(|| {
         TypedefError::Schema(format!(
             "array {field_path} items schema has no TypeDef:* kind"
         ))
     })?;
 
-    let element_stride = if schema::is_fixed_size(element_kind) {
-        schema::type_size(element_kind).unwrap_or(0)
+    let element_stride = if element_kind.is_fixed_size() {
+        element_kind.type_size().unwrap_or(0)
     } else {
         0
     };
@@ -733,14 +731,16 @@ fn resolve_and_walk_variant(
                 "union {field_path} variant could not be resolved: {variant_schema}"
             ))
         })?;
-    let kind = get_typedef_kind_loose(resolved).ok_or_else(|| {
+    let kind = get_typedef_kind_loose_enum(resolved).ok_or_else(|| {
         TypedefError::Schema(format!(
             "union {field_path} variant has no TypeDef:* kind: {resolved}"
         ))
     })?;
     match kind {
-        "TypeDef:Struct" => walk_struct_size(root_schema, resolved, buffer, variant_start, endian),
-        "TypeDef:Union" => {
+        TypeDefKind::Struct => {
+            walk_struct_size(root_schema, resolved, buffer, variant_start, endian)
+        }
+        TypeDefKind::Union => {
             let (_, end) = read_union_value(
                 buffer,
                 root_schema,
@@ -785,7 +785,7 @@ fn resolve_variant_schema<'a>(
         }
         return None;
     }
-    if get_typedef_kind_loose(variant).is_some() {
+    if get_typedef_kind_loose_enum(variant).is_some() {
         Some(variant)
     } else {
         None

crates/alknet-typedef/src/tunion.rs

@@ -11,7 +11,7 @@
 
 use crate::data_access::{read_enum, read_string, read_u16, read_u32, read_u8};
 use crate::error::TypedefError;
-use crate::schema::{get_typedef_kind, parse_discriminator, DiscriminatorKind, Endian, DISCRIMINATOR_PATH, U32_SIZE};
+use crate::schema::{get_typedef_kind, parse_discriminator, DiscriminatorKind, Endian, TypeDefKind, DISCRIMINATOR_PATH, U32_SIZE};
 use serde_json::Value;
 
 const STRING_PREFIX_SIZE: usize = 4;
@@ -60,13 +60,13 @@ pub fn read_byte_discriminator(
         }
     };
 
-    let (disc_value, discriminator_size) = match disc_type.as_str() {
-        "TypeDef:Uint8" => (u32::from(read_u8(buffer, offset, DISCRIMINATOR_PATH)?), 1),
-        "TypeDef:Uint16" => (
+    let (disc_value, discriminator_size) = match disc_type {
+        TypeDefKind::Uint8 => (u32::from(read_u8(buffer, offset, DISCRIMINATOR_PATH)?), 1),
+        TypeDefKind::Uint16 => (
             u32::from(read_u16(buffer, offset, DISCRIMINATOR_PATH, endian)?),
             2,
         ),
-        "TypeDef:Uint32" => (read_u32(buffer, offset, DISCRIMINATOR_PATH, endian)?, 4),
+        TypeDefKind::Uint32 => (read_u32(buffer, offset, DISCRIMINATOR_PATH, endian)?, 4),
         other => {
             return Err(TypedefError::Schema(format!(
                 "unsupported byte discriminator type: {other}"
@@ -139,14 +139,16 @@ pub fn read_field_discriminator(
             ))
         })?;
 
-    let kind = get_typedef_kind(field_schema).ok_or_else(|| {
+    let kind = get_typedef_kind(field_schema)
+        .and_then(|s| s.parse::<TypeDefKind>().ok())
+        .ok_or_else(|| {
             TypedefError::Schema(format!(
                 "discriminator field '{name}' has no TypeDef:* kind"
             ))
         })?;
 
     let (key, discriminator_field_size) = match kind {
-        "TypeDef:String" => {
+        TypeDefKind::String => {
             let s = read_string(buffer, disc_field_offset, &name, endian)?;
             let size =
                 STRING_PREFIX_SIZE
@@ -160,11 +162,11 @@ pub fn read_field_discriminator(
                     })?;
             (s.to_string(), size)
         }
-        "TypeDef:Uint8" => {
+        TypeDefKind::Uint8 => {
             let v = read_u8(buffer, disc_field_offset, &name)?;
             (v.to_string(), 1)
         }
-        "TypeDef:Enum" => {
+        TypeDefKind::Enum => {
             let v = read_enum(buffer, disc_field_offset, &name, endian)?;
             (v.to_string(), U32_SIZE)
         }
@@ -249,10 +251,10 @@ pub fn resolve_variant<'a>(union_schema: &'a Value, key: &str) -> Result<&'a Val
 pub fn discriminator_size(union_schema: &Value) -> Result<usize, TypedefError> {
     let disc = parse_discriminator(union_schema)?;
     match disc {
-        DiscriminatorKind::Byte { disc_type, .. } => match disc_type.as_str() {
-            "TypeDef:Uint8" => Ok(1),
-            "TypeDef:Uint16" => Ok(2),
-            "TypeDef:Uint32" => Ok(4),
+        DiscriminatorKind::Byte { disc_type, .. } => match disc_type {
+            TypeDefKind::Uint8 => Ok(1),
+            TypeDefKind::Uint16 => Ok(2),
+            TypeDefKind::Uint32 => Ok(4),
             other => Err(TypedefError::Schema(format!(
                 "unsupported byte discriminator type: {other}"
             ))),