feat: Add support for IPLS (v2.3) and TIPL/TMCL (v2.4) frames

src/frame/content.rs

@@ -55,6 +55,8 @@ pub enum Content {
     TableOfContents(TableOfContents),
     /// A value containing the parsed contents of a unique file identifier frame (UFID).
     UniqueFileIdentifier(UniqueFileIdentifier),
+    /// A value containing the parsed contents of an involved people list IPLS
+    InvolvedPeopleList(InvolvedPeopleList),
     /// A value containing the bytes of a currently unknown frame type.
     ///
     /// Users that wish to write custom decoders must use [`Content::to_unknown`] instead of
@@ -114,6 +116,19 @@ impl Content {
             Self::UniqueFileIdentifier(unique_file_identifier) => Comparable(vec![Cow::Borrowed(
                 unique_file_identifier.owner_identifier.as_bytes(),
             )]),
+            Self::InvolvedPeopleList(involved_people_list) => Comparable(
+                involved_people_list
+                    .items
+                    .iter()
+                    .flat_map(|item| {
+                        [
+                            Cow::Borrowed(item.involvement.as_bytes()),
+                            Cow::Borrowed(item.involvee.as_bytes()),
+                        ]
+                        .into_iter()
+                    })
+                    .collect(),
+            ),
             Self::Unknown(_) => Incomparable,
         }
     }
@@ -262,6 +277,14 @@ impl Content {
         }
     }
 
+    /// Returns the `InvolvedPeopleList` or None if the value is not `IPLS`
+    pub fn involved_people_list(&self) -> Option<&InvolvedPeopleList> {
+        match self {
+            Content::InvolvedPeopleList(involved_people_list) => Some(involved_people_list),
+            _ => None,
+        }
+    }
+
     /// Returns the `Unknown` or None if the value is not `Unknown`.
     #[deprecated(note = "Use to_unknown")]
     pub fn unknown(&self) -> Option<&[u8]> {
@@ -308,6 +331,9 @@ impl fmt::Display for Content {
             Content::UniqueFileIdentifier(unique_file_identifier) => {
                 write!(f, "{}", unique_file_identifier)
             }
+            Content::InvolvedPeopleList(involved_people_list) => {
+                write!(f, "{}", involved_people_list)
+            }
             Content::Unknown(unknown) => write!(f, "{}", unknown),
         }
     }
@@ -850,6 +876,43 @@ impl From<UniqueFileIdentifier> for Frame {
     }
 }
 
+/// The parsed contents of an IPLS frame.
+#[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
+pub struct InvolvedPeopleList {
+    /// Items in the People List.
+    pub items: Vec<InvolvedPeopleListItem>,
+}
+
+/// The parsed contents of an IPLS frame.
+#[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
+pub struct InvolvedPeopleListItem {
+    /// Role of the involved person.
+    pub involvement: String,
+    /// Name of the involved person.
+    pub involvee: String,
+}
+
+impl fmt::Display for InvolvedPeopleList {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let item_count = self.items.len();
+        for (i, item) in self.items.iter().enumerate() {
+            if i == 0 && item_count > 1 {
+                write!(f, "{}: {} / ", item.involvement, item.involvee)?;
+            } else {
+                write!(f, "{}: {}", item.involvement, item.involvee)?;
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl From<InvolvedPeopleList> for Frame {
+    fn from(c: InvolvedPeopleList) -> Self {
+        Self::with_content("IPLS", Content::InvolvedPeopleList(c))
+    }
+}
+
 #[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[allow(missing_docs)]
 pub struct TableOfContents {

src/frame/mod.rs

@@ -5,10 +5,10 @@ use std::fmt;
 use std::str;
 
 pub use self::content::{
-    Chapter, Comment, Content, EncapsulatedObject, ExtendedLink, ExtendedText, Lyrics,
-    MpegLocationLookupTable, MpegLocationLookupTableReference, Picture, PictureType, Popularimeter,
-    Private, SynchronisedLyrics, SynchronisedLyricsType, TableOfContents, TimestampFormat,
-    UniqueFileIdentifier, Unknown,
+    Chapter, Comment, Content, EncapsulatedObject, ExtendedLink, ExtendedText, InvolvedPeopleList,
+    InvolvedPeopleListItem, Lyrics, MpegLocationLookupTable, MpegLocationLookupTableReference,
+    Picture, PictureType, Popularimeter, Private, SynchronisedLyrics, SynchronisedLyricsType,
+    TableOfContents, TimestampFormat, UniqueFileIdentifier, Unknown,
 };
 pub use self::timestamp::Timestamp;
 
@@ -84,6 +84,7 @@ impl Frame {
             ("APIC", Content::Picture(_)) => Ok(()),
             ("CHAP", Content::Chapter(_)) => Ok(()),
             ("MLLT", Content::MpegLocationLookupTable(_)) => Ok(()),
+            ("IPLS", Content::InvolvedPeopleList(_)) => Ok(()),
             ("PRIV", Content::Private(_)) => Ok(()),
             ("CTOC", Content::TableOfContents(_)) => Ok(()),
             ("UFID", Content::UniqueFileIdentifier(_)) => Ok(()),
@@ -105,6 +106,7 @@ impl Frame {
                     Content::Private(_) => "PrivateFrame",
                     Content::TableOfContents(_) => "TableOfContents",
                     Content::UniqueFileIdentifier(_) => "UFID",
+                    Content::InvolvedPeopleList(_) => "InvolvedPeopleList",
                     Content::Unknown(_) => "Unknown",
                 };
                 Err(Error::new(

src/stream/frame/content.rs

@@ -1,8 +1,8 @@
 use crate::frame::{
-    Chapter, Comment, Content, EncapsulatedObject, ExtendedLink, ExtendedText, Lyrics,
-    MpegLocationLookupTable, MpegLocationLookupTableReference, Picture, PictureType, Popularimeter,
-    Private, SynchronisedLyrics, SynchronisedLyricsType, TableOfContents, TimestampFormat,
-    UniqueFileIdentifier, Unknown,
+    Chapter, Comment, Content, EncapsulatedObject, ExtendedLink, ExtendedText, InvolvedPeopleList,
+    InvolvedPeopleListItem, Lyrics, MpegLocationLookupTable, MpegLocationLookupTableReference,
+    Picture, PictureType, Popularimeter, Private, SynchronisedLyrics, SynchronisedLyricsType,
+    TableOfContents, TimestampFormat, UniqueFileIdentifier, Unknown,
 };
 use crate::stream::encoding::Encoding;
 use crate::stream::frame;
@@ -306,6 +306,17 @@ impl<W: io::Write> Encoder<W> {
         Ok(())
     }
 
+    fn involved_people_list(&mut self, content: &InvolvedPeopleList) -> crate::Result<()> {
+        self.encoding()?;
+        for item in &content.items {
+            self.string(&item.involvement)?;
+            self.delim()?;
+            self.string(&item.involvee)?;
+            self.delim()?;
+        }
+        Ok(())
+    }
+
     fn table_of_contents_content(&mut self, content: &TableOfContents) -> crate::Result<()> {
         self.string_with_other_encoding(Encoding::Latin1, &content.element_id)?;
         self.byte(0)?;
@@ -361,6 +372,7 @@ pub fn encode(
         Content::Private(c) => encoder.private_content(c)?,
         Content::TableOfContents(c) => encoder.table_of_contents_content(c)?,
         Content::UniqueFileIdentifier(c) => encoder.unique_file_identifier_content(c)?,
+        Content::InvolvedPeopleList(c) => encoder.involved_people_list(c)?,
         Content::Unknown(c) => encoder.bytes(&c.data)?,
     };
 
@@ -411,6 +423,7 @@ pub fn decode(
             encoding = Some(enc);
             Ok(content)
         }
+        "IPLS" | "IPL" | "TMCL" | "TIPL" => decoder.involved_people_list(),
         id if id.starts_with('T') => decoder.text_content(),
         id if id.starts_with('W') => decoder.link_content(),
         "GRP1" => decoder.text_content(),
@@ -513,6 +526,62 @@ impl<'a> Decoder<'a> {
         Ok(Content::Text(text))
     }
 
+    fn involved_people_list(mut self) -> crate::Result<Content> {
+        let encoding = self.encoding()?;
+        let end = match self.version {
+            Version::Id3v23 | Version::Id3v24 => find_closing_delim(encoding, self.r),
+            _ => find_delim(encoding, self.r, 0),
+        }.unwrap_or(self.r.len());
+
+        let data = self.bytes(end)?;
+
+        let mut pos = 0;
+        let items = iter::repeat_with(|| {
+            find_delim(encoding, data, pos).map(|next_pos| {
+                let substr = encoding.decode(&data[pos..next_pos]);
+                pos = next_pos + delim_len(encoding);
+                substr
+            }).or_else(|| if pos < data.len() {
+                let substr = encoding.decode(&data[pos..]);
+                pos = data.len();
+                Some(substr)
+            } else {
+                None
+            })
+        })
+        .scan(None, |last_string, string| match (&last_string, string) {
+            (None, Some(string)) => {
+                *last_string = Some(string);
+                Some(Ok(None))
+            }
+            (Some(_), Some(second)) => {
+                let first = last_string.take().expect("option must be some");
+                let result = first.and_then(|involvement| {
+                    second.map(|involvee| {
+                        Some(InvolvedPeopleListItem {
+                            involvement,
+                            involvee,
+                        })
+                    })
+                });
+                Some(result)
+            }
+            (Some(_), None) => {
+                // This can only happen if there is an uneven number of elements.
+                *last_string = None;
+                Some(Err(Error::new(
+                    ErrorKind::Parsing,
+                    "uneven number of IPLS strings",
+                )))
+            }
+            (None, None) => None,
+        })
+        .filter_map(|item| item.transpose())
+        .collect::<crate::Result<Vec<InvolvedPeopleListItem>>>()?;
+
+        Ok(Content::InvolvedPeopleList(InvolvedPeopleList { items }))
+    }
+
     fn link_content(self) -> crate::Result<Content> {
         Ok(Content::Link(String::from_utf8(self.r.to_vec())?))
     }
@@ -1510,6 +1579,101 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_ipls() {
+        check_involved_people_list("IPLS", Version::Id3v23);
+    }
+
+    #[test]
+    fn test_tmcl() {
+        check_involved_people_list("TMCL", Version::Id3v24);
+    }
+
+    #[test]
+    fn test_tipl() {
+        check_involved_people_list("TIPL", Version::Id3v24);
+    }
+
+    fn check_involved_people_list(frame_id: &str, version: Version) {
+        assert!(decode(frame_id, version, &[][..]).is_err());
+
+        println!("valid");
+        for people_list in &[
+            vec![],
+            vec![("involvement", "involvee")],
+            vec![
+                ("double bass", "Israel Crosby"),
+                ("drums (drum set)", "Vernell Fournier"),
+                ("piano", "Ahmad Jamal"),
+                ("producer", "Dave Usher"),
+            ],
+        ] {
+            for encoding in &[
+                Encoding::Latin1,
+                Encoding::UTF8,
+                Encoding::UTF16,
+                Encoding::UTF16BE,
+            ] {
+                println!("`{:?}`, `{:?}`", people_list, encoding);
+                let mut data = Vec::new();
+                data.push(*encoding as u8);
+                for (involvement, involvee) in people_list {
+                    data.extend(bytes_for_encoding(&involvement, *encoding).into_iter());
+                    data.extend(delim_for_encoding(*encoding).into_iter());
+                    data.extend(bytes_for_encoding(&involvee, *encoding).into_iter());
+                    data.extend(delim_for_encoding(*encoding).into_iter());
+                }
+
+                let content = frame::InvolvedPeopleList {
+                    items: people_list
+                        .iter()
+                        .map(|(involvement, involvee)| InvolvedPeopleListItem {
+                            involvement: involvement.to_string(),
+                            involvee: involvee.to_string(),
+                        })
+                        .collect(),
+                };
+                assert_eq!(
+                    *decode(frame_id, version, &data[..])
+                        .unwrap()
+                        .0
+                        .involved_people_list()
+                        .unwrap(),
+                    content
+                );
+                let mut data_out = Vec::new();
+                encode(
+                    &mut data_out,
+                    &&Content::InvolvedPeopleList(content),
+                    Version::Id3v23,
+                    *encoding,
+                )
+                .unwrap();
+                assert_eq!(data, data_out);
+            }
+        }
+
+        println!("invalid");
+        for encoding in &[
+            Encoding::Latin1,
+            Encoding::UTF8,
+            Encoding::UTF16,
+            Encoding::UTF16BE,
+        ] {
+            println!("`{:?}`", encoding);
+            let mut data = Vec::new();
+            data.push(*encoding as u8);
+            data.extend(bytes_for_encoding("involvement", *encoding).into_iter());
+            data.extend(delim_for_encoding(*encoding).into_iter());
+            data.extend(bytes_for_encoding("involvee", *encoding).into_iter());
+            data.extend(delim_for_encoding(*encoding).into_iter());
+            data.extend(bytes_for_encoding("other involvement", *encoding).into_iter());
+            data.extend(delim_for_encoding(*encoding).into_iter());
+            // involveee missing here
+            assert!(decode(frame_id, version, &data[..]).is_err());
+        }
+    }
+
     #[test]
     fn test_mllt_4_4() {
         let mllt = Content::MpegLocationLookupTable(MpegLocationLookupTable {