commit 0ddfb168f50494ee3b1304228f90472fd4b23dc3
Author: Nathan Fisher <nfisher.sr@gmail.com>
Date:   Sun Jul 2 00:44:39 2023 -0400

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..d3d8c6a
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "pk-rs"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..a9c50fc
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "pk-rs"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..453ed02
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,191 @@
+use std::{string::FromUtf8Error, array::TryFromSliceError, fmt, io::{Write, self, Read}, num::TryFromIntError};
+
+#[derive(Debug)]
+pub enum Error {
+    Int(TryFromIntError),
+    Io(io::Error),
+    Utf8(FromUtf8Error),
+    Slice(TryFromSliceError),
+    UnknownFileType,
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Int(e) => write!(f, "{e}"),
+            Self::Utf8(e) => write!(f, "{e}"),
+            Self::Slice(e) => write!(f, "{e}"),
+            Self::Io(e) => write!(f, "{e}"),
+            Self::UnknownFileType => write!(f, "unknown file type"),
+        }
+    }
+}
+
+impl std::error::Error for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            Self::Int(e) => Some(e),
+            Self::Io(e) => Some(e),
+            Self::Utf8(e) => Some(e),
+            Self::Slice(e) => Some(e),
+            _ => None,
+        }
+    }
+}
+
+impl From<TryFromIntError> for Error {
+    fn from(value: TryFromIntError) -> Self {
+        Self::Int(value)
+    }
+}
+
+impl From<io::Error> for Error {
+    fn from(value: io::Error) -> Self {
+        Self::Io(value)
+    }
+}
+
+impl From<FromUtf8Error> for Error {
+    fn from(value: FromUtf8Error) -> Self {
+        Self::Utf8(value)
+    }
+}
+
+impl From<TryFromSliceError> for Error {
+    fn from(value: TryFromSliceError) -> Self {
+        Self::Slice(value)
+    }
+}
+
+#[derive(Debug)]
+pub struct Special {
+    pub major: u32,
+    pub minor: u32,
+}
+
+impl Special {
+    pub fn read<T: Read>(reader: &mut T) -> Result<Self, Error> {
+        let mut buf = [0; 8];
+        reader.read_exact(&mut buf)?;
+        let major: [u8; 4] = buf[..4].try_into()?;
+        let major = u32::from_le_bytes(major);
+        let minor: [u8; 4] = buf[4..].try_into()?;
+        let minor = u32::from_le_bytes(minor);
+        Ok(Self { major, minor })
+    }
+
+    pub fn write<T: Write>(&self, writer: &mut T) -> Result<(), Error> {
+        writer.write_all(&self.major.to_le_bytes())?;
+        writer.write_all(&self.minor.to_le_bytes())?;
+        Ok(())
+    }
+}
+
+#[repr(u8)]
+#[derive(Debug)]
+pub enum FileType {
+    Normal = 0,
+    HardLink(String),
+    SoftLink(String),
+    Directory,
+    Character(Special),
+    Block(Special),
+    Fifo,
+}
+
+impl FileType {
+    pub fn read<T: Read>(reader: &mut T) -> Result<Self, Error> {
+        let mut buf = [0; 1];
+        reader.read_exact(&mut buf)?;
+        match buf[0] {
+            0 => Ok(Self::Normal),
+            1 => {
+                let mut l = [0; 8];
+                reader.read_exact(&mut l)?;
+                let len = u64::from_le_bytes(l);
+                let mut buf = Vec::with_capacity(len.try_into()?);
+                let mut handle = reader.take(len);
+                handle.read(&mut buf)?;
+                let s = String::from_utf8(buf)?;
+                Ok(Self::HardLink(s))
+            },
+            2 => {
+                let mut l = [0; 8];
+                reader.read_exact(&mut l)?;
+                let len = u64::from_le_bytes(l);
+                let mut buf = Vec::with_capacity(len.try_into()?);
+                let mut handle = reader.take(len);
+                handle.read(&mut buf)?;
+                let s = String::from_utf8(buf)?;
+                Ok(Self::SoftLink(s))
+            },
+            3 => Ok(Self::Directory),
+            4 => {
+                let sp = Special::read(reader)?;
+                Ok(Self::Character(sp))
+            },
+            5 => {
+                let sp = Special::read(reader)?;
+                Ok(Self::Block(sp))
+            },
+            6 => Ok(Self::Fifo),
+            _ => Err(Error::UnknownFileType),
+        }
+    }
+
+    pub fn write<T: Write>(&self, writer: &mut T) -> Result<(), Error> {
+        match self {
+            Self::Normal => writer.write_all(&[0])?,
+            Self::HardLink(s) => {
+                writer.write_all(&[1])?;
+                let len = s.len() as u64;
+                writer.write_all(&len.to_le_bytes())?;
+                writer.write_all(s.as_bytes())?;
+            },
+            Self::SoftLink(s) => {
+                writer.write_all(&[2])?;
+                let len = s.len() as u64;
+                writer.write_all(&len.to_le_bytes())?;
+                writer.write_all(s.as_bytes())?;
+            },
+            Self::Directory => writer.write_all(&[3])?,
+            Self::Character(s) => {
+                writer.write_all(&[4])?;
+                s.write(writer)?;
+            },
+            Self::Block(s) => {
+                writer.write_all(&[5])?;
+                s.write(writer)?;
+            },
+            Self::Fifo => writer.write_all(&[6])?,
+        }
+        Ok(())
+    }
+}
+
+#[derive(Debug)]
+pub struct Header {
+    pub name: String,
+    pub filetype: FileType,
+    pub mode: u32,
+    pub uid: u32,
+    pub gid: u32,
+    pub size: u64,
+    pub mtime: u64,
+}
+
+impl Header {
+    pub fn write<T: Write>(&self, writer: &mut T) -> Result<(), Error> {
+        let len = self.name.len() as u64;
+        writer.write_all(&len.to_le_bytes())?;
+        writer.write_all(self.name.as_bytes())?;
+        self.filetype.write(writer)?;
+        [self.mode, self.uid, self.gid].iter().try_for_each(|f| {
+            writer.write_all(&f.to_le_bytes())
+        })?;
+        [self.size, self.mtime].iter().try_for_each(|f| {
+            writer.write_all(&f.to_le_bytes())
+        })?;
+        Ok(())
+    }
+}