move other header parse utils to util module

src/header/common/util.rs

@@ -1,8 +1,9 @@
 //! Utility functions for Header implementations.
 
 use std::str::{FromStr, from_utf8};
+use std::fmt::{mod, Show};
 
-/// Utility function that reads a single raw string when parsing a header
+/// Reads a single raw string when parsing a header
 pub fn from_one_raw_str<T: FromStr>(raw: &[Vec<u8>]) -> Option<T> {
     if raw.len() != 1 {
         return None;
@@ -13,3 +14,32 @@ pub fn from_one_raw_str<T: FromStr>(raw: &[Vec<u8>]) -> Option<T> {
         None => None
     }
 }
+
+/// Reads a comma-delimited raw string into a Vec.
+pub fn from_comma_delimited<T: FromStr>(raw: &[Vec<u8>]) -> Option<Vec<T>> {
+    if raw.len() != 1 {
+        return None;
+    }
+    // we JUST checked that raw.len() == 1, so raw[0] WILL exist.
+    match from_utf8(unsafe { raw.as_slice().unsafe_get(0).as_slice() }) {
+        Some(s) => {
+            Some(s.as_slice()
+                 .split([',', ' '].as_slice())
+                 .filter_map(from_str)
+                 .collect())
+        }
+        None => None
+    }
+}
+
+/// Format an array into a comma-delimited string.
+pub fn fmt_comma_delimited<T: Show>(fmt: &mut fmt::Formatter, parts: &[T]) -> fmt::Result {
+    let last = parts.len() - 1;
+    for (i, part) in parts.iter().enumerate() {
+        try!(part.fmt(fmt));
+        if i < last {
+            try!(", ".fmt(fmt));
+        }
+    }
+    Ok(())
+}