initial structure

1 files changed, 99 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..63fd9bf
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,99 @@
+
+#[macro_use]
+extern crate error_chain;
+extern crate integer_encoding;
+
+use std::io::prelude::*;
+use std::path::Path;
+use std::fs::File;
+use integer_encoding::FixedInt;
+
+mod errors {
+    // Create the Error, ErrorKind, ResultExt, and Result types
+    error_chain! {
+        foreign_links { Fmt(::std::fmt::Error);
+                        Io(::std::io::Error) #[cfg(unix)]; }
+    }
+}
+pub use errors::*;
+
+
+// Abstract access to SLEEP content
+pub trait SleepStorage {
+    fn get_magic(&self) -> u32;
+    fn get_algorithm(&self) -> Option<String>;
+    fn get_entry_size(&self) -> u16;
+    fn read(&self, index: u64) -> Result<&[u8]>;
+    fn write(&self, index: u64, data: &[u8]) -> Result<()>;
+    fn length(&self) -> Result<u64>;
+}
+
+#[derive(Debug)]
+pub struct SleepFile {
+    file: File,
+    magic: u32,
+    entry_size: u16,
+    algorithm_name: Option<String>,
+}
+
+impl SleepFile {
+
+    // TODO: 'from' File trait
+
+    pub fn open(path: &Path, writable: bool) -> Result<SleepFile> {
+
+        // TODO: use writable here
+        let mut f = File::open(path)?;
+        let mut header = [0; 32];
+        f.read_exact(&mut header)?;
+        let version: u8 = header[4];
+        if version != 0 {
+            return Err("Invalid SLEEP header: version must be 0".into());
+        }
+        let algo_len: u8 = header[8];
+        if algo_len > 24 {
+            return Err("Invalid SLEEP header: can't have algo_len > 24".into());
+        }
+        let algorithm_name = if algo_len == 0 { None } else {
+            Some(String::from_utf8_lossy(&header[8..(8+(algo_len as usize))]).into_owned())
+        };
+        // TODO: endian-ness of u16 entry_size
+        Ok(SleepFile {
+            file: f,
+            magic: FixedInt::decode_fixed(&header[0..4]),
+            entry_size: FixedInt::decode_fixed(&header[6..8]),
+            algorithm_name: algorithm_name,
+        })
+    }
+/*
+    pub fn create(path: Path, magic: u32, entry_size: u16, algo: &str) -> Result<SleepFile> {
+        let mut sf = SleepFile {
+
+        };
+    }
+*/
+}
+
+impl SleepStorage for SleepFile {
+
+    fn get_magic(&self) -> u32 { self.magic }
+    fn get_algorithm(&self) -> Option<String> { self.algorithm_name.clone() }
+    fn get_entry_size(&self) -> u16 { self.entry_size }
+
+    fn read(&self, index: u64) -> Result<&[u8]> {
+        unimplemented!()
+        //Err("unimplemented")
+    }
+
+    fn write(&self, index: u64, data: &[u8]) -> Result<()> {
+        Ok(())
+    }
+
+    fn length(&self) -> Result<u64> {
+        let length = self.file.metadata()?.len();
+        // TODO: assert that length >= 32
+        // TODO: assert that (length - 32) % self.entry_size == 0
+        return Ok((length - 32) / (self.entry_size as u64))
+    }
+
+}