1 files changed, 56 insertions, 0 deletions
diff --git a/src/codec.rs b/src/codec.rs
new file mode 100644
index 0000000..3bba1c6
--- /dev/null
+++ b/src/codec.rs
@@ -0,0 +1,56 @@
+#![warn(clippy::pedantic)]
+
+use std::collections::HashSet;
+use std::convert::TryFrom;
+
+use super::context::Context;
+use super::error::Error;
+use super::percent_encoded_character_decoder::PercentEncodedCharacterDecoder;
+
+pub fn decode_element<T>(
+    element: T,
+    allowed_characters: &'static HashSet<char>,
+    context: Context
+) -> Result<Vec<u8>, Error>
+    where T: AsRef<str>
+{
+    let mut decoding_pec = false;
+    let mut pec_decoder = PercentEncodedCharacterDecoder::new();
+    element
+        .as_ref()
+        .chars()
+        .filter_map(|c| {
+            if decoding_pec {
+                pec_decoder
+                    .next(c)
+                    .map_err(Into::into)
+                    .transpose()
+                    .map(|c| {
+                        decoding_pec = false;
+                        c
+                    })
+            } else if c == '%' {
+                decoding_pec = true;
+                None
+            } else if allowed_characters.contains(&c) {
+                Some(Ok(c as u8))
+            } else {
+                Some(Err(Error::IllegalCharacter(context)))
+            }
+        })
+        .collect()
+}
+
+pub fn encode_element(
+    element: &[u8],
+    allowed_characters: &HashSet<char>
+) -> String {
+    element.iter()
+        .map(|ci| {
+            match char::try_from(*ci) {
+                Ok(c) if allowed_characters.contains(&c) => c.to_string(),
+                _ => format!("%{:X}", ci),
+            }
+        })
+        .collect::<String>()
+}