Added generic header crate.

Cargo.toml

@@ -4,6 +4,7 @@ members = [
   "ndsz-nds",
   "ndsz-fat",
   "ndsz-narc",
+  "ndsz-generic-header",
   "ndsz-mknds",
   "ndsz-unnds",
   "ndsz-unnarc",

ndsz-generic-header/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+edition = "2018"
+name = "ndsz-generic-header"
+version = "0.0.0"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+# Bytes
+byteorder = "1.4.3"
+
+# Util
+zutil = {git = "https://github.com/Zenithsiz/zutil", rev = "2a029369ac5aa4e7dbd6f6afb78ae419ee18666f"}
+
+# Error handling
+thiserror = "1.0.28"
+
+# Logging
+log = "0.4.14"
+
+# Serde
+serde = {version = "1.0.130", features = ["derive"]}

ndsz-generic-header/src/error.rs

@@ -0,0 +1,13 @@
+//! Errors
+
+/// Error for [`Header::from_bytes`](super::Header::from_bytes)
+#[derive(PartialEq, Clone, Debug, thiserror::Error)]
+pub enum FromBytesError {
+	/// Wrong constant
+	#[error("Wrong constant: {constant:#x}")]
+	WrongConstant { constant: u32 },
+
+	/// Wrong header size
+	#[error("Wrong header size: {header_size:#x}")]
+	WrongHeaderSize { header_size: u16 },
+}

ndsz-generic-header/src/lib.rs

@@ -0,0 +1,55 @@
+//! Generic header for most nds file formats
+//!
+//! Adapted from `https://loveemu.hatenablog.com/entry/20091002/nds_formats`,
+//! which itself is adapted from `http://llref.emutalk.net/nds_formats.htm` (dead link)
+
+// Modules
+mod error;
+
+// Exports
+pub use error::FromBytesError;
+
+// Imports
+use byteorder::{ByteOrder, LittleEndian};
+
+/// Header
+#[derive(PartialEq, Eq, Clone, Copy, Debug)]
+pub struct Header {
+	/// Magic
+	pub magic: [u8; 4],
+
+	/// Section size
+	pub section_size: u32,
+
+	/// Number of sub-sections
+	pub sub_sections_len: u16,
+}
+
+impl Header {
+	/// Parses a header from bytes
+	pub fn from_bytes(bytes: &[u8; 0x10]) -> Result<Self, FromBytesError> {
+		let bytes = zutil::array_split!(bytes,
+			magic           : [0x4],
+			constant        : [0x4],
+			section_size    : [0x4],
+			header_size     : [0x2],
+			sub_sections_len: [0x2],
+		);
+
+		let constant = LittleEndian::read_u32(bytes.constant);
+		let header_size = LittleEndian::read_u16(bytes.header_size);
+		if constant != 0xfffe0001 {
+			return Err(FromBytesError::WrongConstant { constant });
+		}
+		if header_size != 0x10 {
+			return Err(FromBytesError::WrongHeaderSize { header_size });
+		}
+
+
+		Ok(Self {
+			magic:            *bytes.magic,
+			section_size:     LittleEndian::read_u32(bytes.section_size),
+			sub_sections_len: LittleEndian::read_u16(bytes.sub_sections_len),
+		})
+	}
+}