pkgs/profpatsch: rename encode to netencode

Less generic, has the spirit of “netstrings, but extended to a
structured encoding format”.

1 files changed, 399 insertions, 0 deletions

diff --git a/pkgs/profpatsch/netencode/netencode.rs b/pkgs/profpatsch/netencode/netencode.rs
new file mode 100644
index 00000000..b83aca7b
--- /dev/null
+++ b/pkgs/profpatsch/netencode/netencode.rs
@@ -0,0 +1,399 @@
+extern crate nom;
+
+use std::collections::HashMap;
+use std::io::Write;
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum T {
+    // Unit
+    Unit,
+    // Naturals
+    N3(u8),
+    N6(u64),
+    N7(u128),
+    // Integers
+    I3(i8),
+    I6(i64),
+    I7(i128),
+    // Text
+    // TODO: make into &str
+    Text(String),
+    // Tags
+    Sum(Tag),
+    // TODO: make into &str
+    Record(HashMap<String, Box<T>>),
+    List(Box<Vec<T>>),
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Tag {
+    // TODO: make into &str
+    pub tag: String,
+    pub val: Box<T>
+}
+
+fn encode_tag<W: Write>(w: &mut W, tag: String, val: T) -> std::io::Result<()> {
+    write!(w, "<{}:{}|", tag.len(), tag)?;
+    encode(w, val)?;
+    Ok(())
+}
+
+pub fn encode<W: Write>(w: &mut W, t: T) -> std::io::Result<()> {
+  match t {
+      T::Unit => write!(w, "u,"),
+      T::N3(n) => write!(w, "n3:{},", n),
+      T::N6(n) => write!(w, "n6:{},", n),
+      T::N7(n) => write!(w, "n7:{},", n),
+      T::I3(i) => write!(w, "i3:{},", i),
+      T::I6(i) => write!(w, "i6:{},", i),
+      T::I7(i) => write!(w, "i7:{},", i),
+      T::Text(s) => write!(w, "t{}:{},", s.len(), s),
+      T::Sum(Tag{tag, val}) => encode_tag(w, tag, *val),
+      T::Record(m) => {
+          let mut c = std::io::Cursor::new(vec![]);
+          for (k, v) in m {
+              encode_tag(&mut c, k, *v)?;
+          }
+          write!(w, "{{{}:", c.get_ref().len())?;
+          w.write(c.get_ref())?;
+          write!(w, "}}")
+      },
+      T::List(l) => {
+          let mut c = std::io::Cursor::new(vec![]);
+          for v in *l {
+              encode(&mut c, v)?;
+          };
+          write!(w, "[{}:", c.get_ref().len())?;
+          w.write(c.get_ref())?;
+          write!(w, "]")
+      }
+  }
+}
+
+pub fn dict(d: Vec<(String, T)>) -> T {
+    T::Record(
+        d.into_iter()
+            .map(|(k,v)| (k, Box::new(v)))
+            // to ignore duplicate entries after the first
+            .rev()
+            .collect::<HashMap<_,_>>())
+}
+
+pub fn text(s: String) -> T {
+    T::Text(s)
+}
+
+mod parse {
+    use super::{T, Tag};
+
+    use std::str::FromStr;
+    use std::ops::Neg;
+    use std::collections::HashMap;
+
+    use nom::{IResult};
+    use nom::bytes::complete::{tag, take};
+    use nom::branch::{alt};
+    use nom::character::complete::{digit1, char};
+    use nom::sequence::{tuple};
+    use nom::combinator::{map, map_res, flat_map, opt};
+    use nom::error::{context, ErrorKind, ParseError};
+
+    fn unit_t(s: &[u8]) -> IResult<&[u8], ()> {
+        let (s, _) = context("unit", tag("u,"))(s)?;
+        Ok((s, ()))
+    }
+
+    fn usize_t(s: &[u8]) -> IResult<&[u8], usize> {
+        context(
+            "usize",
+            map_res(
+                map_res(digit1, |n| std::str::from_utf8(n)),
+                |s| s.parse::<usize>())
+        )(s)
+    }
+
+
+    fn uint_t<'a, I: FromStr + 'a>(t: &'static str) -> impl Fn(&'a [u8]) -> IResult<&'a [u8], I> {
+        move |s: &'a [u8]| {
+            let (s, (_, _, int, _)) = tuple((
+                tag(t.as_bytes()),
+                char(':'),
+                map_res(
+                    map_res(digit1, |n: &[u8]| std::str::from_utf8(n)),
+                    |s| s.parse::<I>()
+                ),
+                char(',')
+            ))(s)?;
+            Ok((s, int))
+        }
+    }
+
+    fn int_t<'a, I: FromStr + Neg<Output=I>>(t: &'static str) -> impl Fn(&'a [u8]) -> IResult<&[u8], I> {
+        context(
+            t,
+            move |s: &'a [u8]| {
+                let (s, (_, _, neg, int, _)) = tuple((
+                    tag(t.as_bytes()),
+                    char(':'),
+                    opt(char('-')),
+                    map_res(
+                        map_res(digit1, |n: &[u8]| std::str::from_utf8(n)),
+                        |s| s.parse::<I>()
+                    ),
+                    char(',')
+                ))(s)?;
+                let res = match neg {
+                    Some(_) => -int,
+                    None => int,
+                };
+                Ok((s, res))
+            }
+        )
+    }
+
+    fn tag_t(s: &[u8]) -> IResult<&[u8], Tag> {
+        let (s, (_, len, _)) = tuple((
+            char('<'),
+            usize_t,
+            char(':'),
+        ))(s)?;
+        let (s, (tag, _, recurse)) = tuple((
+            take(len),
+            char('|'),
+            // recurses into the main parser
+            t_t
+        ))(s)?;
+        Ok((s, Tag {
+            tag: std::str::from_utf8(tag)
+                .map_err(|_| nom::Err::Failure((s, ErrorKind::Char)))
+                .map(|s| s.to_string())?,
+            val: Box::new(recurse)
+        }))
+    }
+
+    /// parse text scalar (`t5:hello,`)
+    fn text(s: &[u8]) -> IResult<&[u8], T> {
+        let (s, (_, len, _)) = tuple((
+            char('t'),
+            usize_t,
+            char(':')
+        ))(s)?;
+        let (s, (res, _)) = tuple((
+            take(len),
+            char(',')
+        ))(s)?;
+        Ok((s, T::Text(
+            std::str::from_utf8(res)
+                .map_err(|_| nom::Err::Failure((s, ErrorKind::Char)))
+                .map(|s| s.to_string())?,
+        )))
+    }
+
+    fn list_t(s: &[u8]) -> IResult<&[u8], Vec<T>> {
+        let (s, (_, _, _, vec, _)) = tuple((
+            char('['),
+            usize_t,
+            char(':'),
+            nom::multi::many0(t_t),
+            char(']')
+        ))(s)?;
+        Ok((s, vec))
+    }
+
+    fn record_t(s: &[u8]) -> IResult<&[u8], HashMap<String, Box<T>>> {
+        let (s, (_, _, _, map, _)) = tuple((
+            char('{'),
+            usize_t,
+            char(':'),
+            nom::multi::fold_many1(
+                tag_t,
+                HashMap::new(),
+                |mut acc: HashMap<_, _>, Tag { tag, val }| {
+                    // ignore duplicated tag names that appear later
+                    if !acc.contains_key(&tag) {
+                        acc.insert(tag, val);
+                    }
+                    acc
+                }
+            ),
+            char('}')
+        ))(s)?;
+        Ok((s, map))
+    }
+
+    fn t_t(s: &[u8]) -> IResult<&[u8], T>  {
+        alt((
+            text,
+            map(unit_t, |_| T::Unit),
+            map(tag_t, |t| T::Sum(t)),
+            map(list_t, |l| T::List(Box::new(l))),
+            map(record_t, |p| T::Record(p)),
+
+            // 8, 64 and 128 bit
+            map(uint_t("n3"), |u| T::N3(u)),
+            map(uint_t("n6"), |u| T::N6(u)),
+            map(uint_t("n7"), |u| T::N7(u)),
+            map(int_t("i3"), |u| T::I3(u)),
+            map(int_t("i6"), |u| T::I6(u)),
+            map(int_t("i7"), |u| T::I7(u)),
+
+            // less common
+            map(uint_t("n1"), |u| T::N3(u)),
+            map(uint_t("n2"), |u| T::N3(u)),
+            map(uint_t("n4"), |u| T::N6(u)),
+            map(uint_t("n5"), |u| T::N6(u)),
+            map(int_t("i1"), |u| T::I3(u)),
+            map(int_t("i2"), |u| T::I3(u)),
+            map(int_t("i4"), |u| T::I6(u)),
+            map(int_t("i5"), |u| T::I6(u)),
+            // TODO: 8, 9 not supported
+        ))(s)
+    }
+
+    #[cfg(test)]
+    mod tests {
+        use super::*;
+
+        #[test]
+        fn test_parse_unit_t() {
+            assert_eq!(
+                unit_t("u,".as_bytes()),
+                Ok(("".as_bytes(), ()))
+            );
+        }
+
+        #[test]
+        fn test_parse_usize_t() {
+            assert_eq!(
+                usize_t("32foo".as_bytes()),
+                Ok(("foo".as_bytes(), 32))
+            );
+        }
+
+        #[test]
+        fn test_parse_int_t() {
+            assert_eq!(
+                uint_t::<u8>("n3")("n3:42,abc".as_bytes()),
+                Ok(("abc".as_bytes(), 42))
+            );
+            assert_eq!(
+                uint_t::<u8>("n3")("n3:1024,abc".as_bytes()),
+                Err(nom::Err::Error(("1024,abc".as_bytes(), nom::error::ErrorKind::MapRes)))
+            );
+            assert_eq!(
+                int_t::<i64>("i6")("i6:-23,abc".as_bytes()),
+                Ok(("abc".as_bytes(), -23))
+            );
+            assert_eq!(
+                int_t::<i128>("i3")("i3:0,:abc".as_bytes()),
+                Ok((":abc".as_bytes(), 0))
+            );
+            assert_eq!(
+                uint_t::<u8>("n7")("n7:09,".as_bytes()),
+                Ok(("".as_bytes(), 9))
+            );
+            // assert_eq!(
+            //     length("c"),
+            //     Err(nom::Err::Error(("c", nom::error::ErrorKind::Digit)))
+            // );
+            // assert_eq!(
+            //     length(":"),
+            //     Err(nom::Err::Error((":", nom::error::ErrorKind::Digit)))
+            // );
+        }
+
+        #[test]
+        fn test_parse_text() {
+            assert_eq!(
+                text("t5:hello,".as_bytes()),
+                Ok(("".as_bytes(), T::Text("hello".to_owned())))
+            );
+            assert_eq!(
+                text("t4:fo,".as_bytes()),
+                // TODO: way better parse error messages
+                Err(nom::Err::Error(("fo,".as_bytes(), nom::error::ErrorKind::Eof)))
+            );
+            assert_eq!(
+                text("t9:今日は,".as_bytes()),
+                Ok(("".as_bytes(), T::Text("今日は".to_owned())))
+            );
+        }
+
+        #[test]
+        fn test_list() {
+            assert_eq!(
+                list_t("[0:]".as_bytes()),
+                Ok(("".as_bytes(), vec![]))
+            );
+            assert_eq!(
+                list_t("[6:u,u,u,]".as_bytes()),
+                Ok(("".as_bytes(), vec![
+                    T::Unit,
+                    T::Unit,
+                    T::Unit,
+                ]))
+            );
+            assert_eq!(
+                list_t("[15:u,[7:t3:foo,]u,]".as_bytes()),
+                Ok(("".as_bytes(), vec![
+                    T::Unit,
+                    T::List(Box::new(vec![T::Text("foo".to_owned())])),
+                    T::Unit,
+                ]))
+            );
+        }
+
+        #[test]
+        fn test_record() {
+            assert_eq!(
+                record_t("{21:<1:a|u,<1:b|u,<1:c|u,}".as_bytes()),
+                Ok(("".as_bytes(), vec![
+                    ("a".to_owned(), Box::new(T::Unit)),
+                    ("b".to_owned(), Box::new(T::Unit)),
+                    ("c".to_owned(), Box::new(T::Unit)),
+                ].into_iter().collect::<HashMap<String, Box<T>>>()))
+            );
+            // duplicated keys are ignored (first is taken)
+            assert_eq!(
+                record_t("{25:<1:a|u,<1:b|u,<1:a|i1:-1,}".as_bytes()),
+                Ok(("".as_bytes(), vec![
+                    ("a".to_owned(), Box::new(T::Unit)),
+                    ("b".to_owned(), Box::new(T::Unit)),
+                ].into_iter().collect::<HashMap<_,_>>()))
+            );
+        }
+
+        #[test]
+        fn test_parse() {
+            assert_eq!(
+                t_t("n3:255,".as_bytes()),
+                Ok(("".as_bytes(), T::N3(255)))
+            );
+            assert_eq!(
+                t_t("t6:halloo,".as_bytes()),
+                Ok(("".as_bytes(), T::Text("halloo".to_owned())))
+            );
+            assert_eq!(
+                t_t("<3:foo|t6:halloo,".as_bytes()),
+                Ok(("".as_bytes(), T::Sum (Tag {
+                    tag: "foo".to_owned(),
+                    val: Box::new(T::Text("halloo".to_owned()))
+                })))
+            );
+            // { a: Unit
+            // , foo: List <A: Unit | B: List i3> }
+            assert_eq!(
+                t_t("{49:<1:a|u,<3:foo|[30:<1:A|u,<1:A|u,<1:B|[7:i3:127,]]}".as_bytes()),
+                Ok(("".as_bytes(), T::Record(vec![
+                    ("a".to_owned(), Box::new(T::Unit)),
+                    ("foo".to_owned(), Box::new(T::List(Box::new(vec![
+                        T::Sum(Tag { tag: "A".to_owned(), val: Box::new(T::Unit) }),
+                        T::Sum(Tag { tag: "A".to_owned(), val: Box::new(T::Unit) }),
+                        T::Sum(Tag { tag: "B".to_owned(), val: Box::new(T::List(Box::new(vec![T::I3(127)]))) }),
+                    ]))))
+                ].into_iter().collect::<HashMap<String, Box<T>>>())))
+            );
+        }
+
+    }
+}