♻️ Extract zero-copy interface

.gitignore

@@ -1 +1,2 @@
 /target
+/Cargo.lock

src/lib.rs

@@ -7,65 +7,11 @@ use std::mem::size_of;
 
 use byteorder::{ByteOrder, LittleEndian, ReadBytesExt};
 
-pub mod consts {
-use iota::iota;
-iota! {
-	pub const VERSION: usize = iota;
-			, FILESIZE
-			, FLAGS
-			, NUM_TEXT
-			, OFS_TEXT
-			, NUM_MESHES
-			, OFS_MESHES
-			, NUM_VERTEXARRAYS
-			, NUM_VERTEXES
-			, OFS_VERTEXARRAYS
-			, NUM_TRIANGLES
-			, OFS_TRIANGLES
-			, OFS_ADJACENCY
-			, NUM_JOINTS
-			, OFS_JOINTS
-			, NUM_POSES
-			, OFS_POSES
-			, NUM_ANIMS
-			, OFS_ANIMS
-			, NUM_FRAMES
-			, NUM_FRAMECHANNELS
-			, OFS_FRAMES
-			, OFS_BOUNDS
-			, NUM_COMMENT
-			, OFS_COMMENT
-			, NUM_EXTENSIONS
-			, OFS_EXTENSIONS
-}
-}
+pub mod names;
+pub mod zero_copy;
 
-pub mod types {
-iota! {
-	pub const POSITION: usize = iota;
-			, TEXCOORD
-			, NORMAL
-			, TANGENT
-			, BLENDINDEXES
-			, BLENDWEIGHTS
-			, COLOR
-}
-	pub const CUSTOM: usize       = 0x10;
-}
-
-pub mod formats {
-iota! {
-	pub const BYTE: u32 = iota;
-			, UBYTE
-			, SHORT
-			, USHORT
-			, INT
-			, UINT
-			, HALF
-			, FLOAT
-			, DOUBLE
-}
-}
+pub use crate::names::consts;
+pub use crate::names::types;
 
 #[derive (Debug, Default)]
 pub struct Mesh {
@@ -109,13 +55,14 @@ pub enum ModelLoadErr {
 	ParseVertexArrayFailed,
 }
 
+use crate::names::MAGIC;
+
 impl Header {
 	pub fn from_slice (input: &[u8]) -> Result <Header, ModelLoadErr> {
-		let magic = b"INTERQUAKEMODEL\0";
-		if &input [0..magic.len ()] != magic {
+		if &input [0..MAGIC.len ()] != MAGIC {
 			return Err (ModelLoadErr::BadMagic);
 		}
-		let input = &input [magic.len ()..];
+		let input = &input [MAGIC.len ()..];
 		
 		let mut header = Header::default ();
 		LittleEndian::read_u32_into (&input [0..header.fields.len () * size_of::<u32> ()], &mut header.fields);
@@ -288,18 +235,14 @@ impl <'a> Model <'a> {
 
 #[cfg (test)]
 mod test {
-	use super::*;
-	
-	use std::fs::File;
-	use std::io::Read;
 	use std::path::Path;
 	
-	#[test]
-	pub fn nothing () {
-		
-	}
-	
 	fn load_file <P: AsRef <Path>> (filename: P) -> Vec <u8> {
+		use std::convert::TryInto;
+		use std::fs::File;
+		use std::io::Read;
+		
+		
 		let mut f = File::open (filename).unwrap ();
 		let mut data = vec! [0u8; f.metadata ().unwrap ().len ().try_into ().unwrap ()];
 		f.read_exact (&mut data).unwrap ();
@@ -308,6 +251,8 @@ mod test {
 	
 	#[test]
 	pub fn load_models () {
+		use super::*;
+		
 		let airplane_bytes = load_file ("airplane.iqm");
 		let arrow_bytes = load_file ("arrow.iqm");
 		let truk_bytes = load_file ("truk.iqm");
@@ -316,7 +261,7 @@ mod test {
 		let arrow = Model::from_slice (&arrow_bytes).unwrap ();
 		let truk = Model::from_slice (&truk_bytes).unwrap ();
 		
-		use consts::*;
+		use crate::names::consts::*;
 		
 		assert_eq! (airplane.header.fields [NUM_VERTEXES], 304);
 		assert_eq! (airplane.header.fields [NUM_TRIANGLES], 156);
@@ -333,4 +278,17 @@ mod test {
 		assert_eq! (truk.meshes.len (), 5);
 		assert_eq! (truk.vertexarrays.len (), 4);
 	}
+	
+	#[test]
+	pub fn load_zero_copy () {
+		use crate::zero_copy::*;
+		
+		let airplane_bytes = load_file ("airplane.iqm");
+		let arrow_bytes = load_file ("arrow.iqm");
+		let truk_bytes = load_file ("truk.iqm");
+		
+		let airplane = Model::get_root (&airplane_bytes);
+		let arrow = Model::get_root (&arrow_bytes);
+		let truk = Model::get_root (&truk_bytes);
+	}
 }

src/names.rs

@@ -0,0 +1,82 @@
+pub const MAGIC: &[u8] = b"INTERQUAKEMODEL\0";
+
+pub mod consts {
+use iota::iota;
+iota! {
+	pub const VERSION: usize = iota;
+			, FILESIZE
+			, FLAGS
+			, NUM_TEXT
+			, OFS_TEXT
+			, NUM_MESHES
+			, OFS_MESHES
+			, NUM_VERTEXARRAYS
+			, NUM_VERTEXES
+			, OFS_VERTEXARRAYS
+			, NUM_TRIANGLES
+			, OFS_TRIANGLES
+			, OFS_ADJACENCY
+			, NUM_JOINTS
+			, OFS_JOINTS
+			, NUM_POSES
+			, OFS_POSES
+			, NUM_ANIMS
+			, OFS_ANIMS
+			, NUM_FRAMES
+			, NUM_FRAMECHANNELS
+			, OFS_FRAMES
+			, OFS_BOUNDS
+			, NUM_COMMENT
+			, OFS_COMMENT
+			, NUM_EXTENSIONS
+			, OFS_EXTENSIONS
+}
+
+iota! {
+	pub const 
+		  VA_TYPE: usize = iota;
+		, VA_FLAGS
+		, VA_FORMAT
+		, VA_SIZE
+		, VA_OFFSET
+		, VA_FIELD_COUNT
+}
+
+iota! {
+	pub const
+		  MESH_NAME: usize = iota;
+		, MESH_MATERIAL
+		, MESH_FIRST_VERTEX
+		, MESH_NUM_VERTEXES
+		, MESH_FIRST_TRIANGLE
+		, MESH_NUM_TRIANGLES
+		, MESH_FIELD_COUNT
+}
+}
+
+pub mod types {
+iota! {
+	pub const POSITION: usize = iota;
+			, TEXCOORD
+			, NORMAL
+			, TANGENT
+			, BLENDINDEXES
+			, BLENDWEIGHTS
+			, COLOR
+}
+	pub const CUSTOM: usize       = 0x10;
+}
+
+pub mod formats {
+iota! {
+	pub const BYTE: u32 = iota;
+			, UBYTE
+			, SHORT
+			, USHORT
+			, INT
+			, UINT
+			, HALF
+			, FLOAT
+			, DOUBLE
+}
+}

src/zero_copy.rs

@@ -0,0 +1,166 @@
+use std::convert::TryFrom;
+use std::mem::size_of;
+
+use byteorder::{ByteOrder, LittleEndian};
+
+pub struct Model <'data> {
+	pub data: &'data [u8],
+}
+
+pub struct VertexArray <'data> {
+	pub model: &'data Model <'data>,
+	ofs: usize,
+}
+
+pub struct Mesh <'data> {
+	pub model: &'data Model <'data>,
+	ofs: usize,
+}
+
+pub struct VertexArrays <'data> {
+	model: &'data Model <'data>,
+	idx: usize,
+}
+
+pub struct Meshes <'data> {
+	model: &'data Model <'data>,
+	idx: usize,
+}
+
+#[derive (Debug)]
+pub enum Error {
+	BadMagic,
+	UnsupportedVersion,
+	HeaderTooShort,
+	ParseMeshFailed,
+	ParseVertexArrayFailed,
+}
+
+use crate::names;
+use names::consts;
+use names::MAGIC;
+
+pub const HEADER_FIELD_COUNT: usize = 27;
+
+// If you are using IQM models on an 8-bit or 16-bit microcontroller
+// you're smarter than me anyway
+
+fn usize_from (x: u32) -> usize {
+	usize::try_from (x).unwrap ()
+}
+
+impl <'data> Iterator for VertexArrays <'data> {
+	type Item = VertexArray <'data>;
+	
+	fn next (&mut self) -> Option <Self::Item> {
+		if self.idx >= usize_from (self.model.header_field (crate::names::consts::NUM_VERTEXARRAYS)) {
+			return None;
+		}
+		
+		let result = self.model.vertexarray (self.idx);
+		
+		self.idx += 1;
+		Some (result)
+	}
+}
+
+impl <'data> Iterator for Meshes <'data> {
+	type Item = Mesh <'data>;
+	
+	fn next (&mut self) -> Option <Self::Item> {
+		if self.idx >= usize_from (self.model.header_field (crate::names::consts::NUM_MESHES)) {
+			return None;
+		}
+		
+		let result = self.model.mesh (self.idx);
+		
+		self.idx += 1;
+		Some (result)
+	}
+}
+
+impl <'data> Model <'data> {
+	pub fn get_root (data: &[u8]) -> Result <Model, Error> {
+		if &data [0..MAGIC.len ()] != MAGIC {
+			return Err (Error::BadMagic);
+		}
+		
+		if data.len () < MAGIC.len () + size_of::<u32> () * HEADER_FIELD_COUNT {
+			return Err (Error::HeaderTooShort);
+		}
+		
+		let m = Model {
+			data,
+		};
+		
+		if m.header_field (consts::VERSION) != 2 {
+			return Err (Error::UnsupportedVersion);
+		}
+		
+		Ok (m)
+	}
+	
+	pub fn header_field (&self, idx: usize) -> u32 {
+		LittleEndian::read_u32 (&self.data [MAGIC.len () + idx * size_of::<u32> ()..])
+	}
+	
+	pub fn vertexarray (&self, idx: usize) -> VertexArray {
+		use crate::names::consts::*;
+		assert! (idx < usize_from (self.header_field (NUM_VERTEXARRAYS)));
+		
+		let vertexarray_stride = VA_FIELD_COUNT * size_of::<u32> ();
+		
+		VertexArray {
+			model: self,
+			ofs: usize_from (self.header_field (OFS_VERTEXARRAYS)) + idx * vertexarray_stride,
+		}
+	}
+	
+	pub fn mesh (&self, idx: usize) -> Mesh {
+		use crate::names::consts::*;
+		assert! (idx < usize_from (self.header_field (NUM_MESHES)));
+		
+		let mesh_stride = MESH_FIELD_COUNT * size_of::<u32> ();
+		
+		Mesh {
+			model: self,
+			ofs: usize_from (self.header_field (OFS_MESHES)) + idx * mesh_stride,
+		}
+	}
+	
+	pub fn vertexarrays (&self) -> VertexArrays {
+		VertexArrays {
+			model: self,
+			idx: 0,
+		}
+	}
+	
+	pub fn meshes (&self) -> Meshes {
+		Meshes {
+			model: self,
+			idx: 0,
+		}
+	}
+}
+
+impl <'data> VertexArray <'data> {
+	pub fn field (&self, idx: usize) -> u32 {
+		LittleEndian::read_u32 (&self.model.data [self.ofs + idx * size_of::<u32>()..])
+	}
+	
+	pub fn get_vertex_slice (&self) -> &[u8] {
+		use names::consts::*;
+		
+		let stride = size_of::<f32> () * usize_from (self.field (VA_SIZE));
+		let offset = usize_from (self.field (VA_OFFSET));
+		let num_bytes = stride * usize_from (self.model.header_field (NUM_VERTEXES));
+		
+		&self.model.data [offset..offset + num_bytes]
+	}
+}
+
+impl <'data> Mesh <'data> {
+	pub fn field (&self, idx: usize) -> u32 {
+		LittleEndian::read_u32 (&self.model.data [self.ofs + idx * size_of::<u32>()..])
+	}
+}