restructure how agents are constructed

The old function turned a bit into a mess, so the functionality is now
split up.

1 files changed, 42 insertions, 0 deletions

diff --git a/src/raw/mod.rs b/src/raw/mod.rs
index 7451b5a..50ad9b4 100644
--- a/src/raw/mod.rs
+++ b/src/raw/mod.rs
@@ -18,6 +18,7 @@ pub mod parser;
 pub use self::parser::{parse_file, Evtc, ParseError, ParseResult};
 
 use std::io::{Read, Seek, BufReader};
+use std::ffi::CStr;
 
 /// Parse a complete log that was compressed as a zip file.
 pub fn parse_zip<T: Read + Seek>(input: &mut T) -> ParseResult<Evtc> {
@@ -25,3 +26,44 @@ pub fn parse_zip<T: Read + Seek>(input: &mut T) -> ParseResult<Evtc> {
     let mut file = BufReader::new(archive.by_index(0)?);
     parse_file(&mut file)
 }
+
+/// Return a [`CStr`][CStr] up to the first nul byte.
+///
+/// This is different to [`CStr::from_bytes_with_nul`][CStr::from_bytes_with_nul] in that it stops
+/// at the first nul byte instead of raising an error.
+///
+/// If the slice does not end with a nul byte, this function returns `None`.
+pub fn cstr_up_to_nul(bytes: &[u8]) -> Option<&CStr> {
+    let index = bytes.iter().position(|c| *c == 0)?;
+    CStr::from_bytes_with_nul(&bytes[..index + 1]).ok()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_cstr_up_to_nul_terminated() {
+        let bytes = b"foo\0";
+        let cstr = cstr_up_to_nul(bytes).unwrap();
+        assert_eq!(cstr.to_bytes(), b"foo");
+    }
+
+    #[test]
+    fn test_cstr_up_to_nul_multiple() {
+        let bytes = b"foo\0\0\0";
+        let cstr = cstr_up_to_nul(bytes).unwrap();
+        assert_eq!(cstr.to_bytes(), b"foo");
+
+        let bytes = b"foo\0bar\0\0";
+        let cstr = cstr_up_to_nul(bytes).unwrap();
+        assert_eq!(cstr.to_bytes(), b"foo");
+    }
+
+    #[test]
+    fn test_cstr_up_to_nul_unterminated() {
+        let bytes = b"foo";
+        let cstr = cstr_up_to_nul(bytes);
+        assert!(cstr.is_none());
+    }
+}