Cue point implementation

src/cue.rs

@@ -0,0 +1,253 @@
+use super::fourcc::{FourCC,ReadFourCC, LABL_SIG, NOTE_SIG, LTXT_SIG};
+use super::list_form::collect_list_form;
+use byteorder::{ReadBytesExt, LittleEndian};
+
+use std::io::{Cursor, Error, Read};
+use std::str;
+
+#[derive(Copy,Clone, Debug)]
+struct RawCue {
+    cue_point_id : u32,
+    frame : u32,
+    chunk_id : FourCC,
+    chunk_start : u32,
+    block_start : u32,
+    frame_offset : u32
+}
+
+impl RawCue {
+    fn read_from(data : &[u8]) -> Result<Vec<Self>,Error> {
+        let mut rdr = Cursor::new(data);
+        let count = rdr.read_u32::<LittleEndian>()?;
+        let mut retval : Vec<Self> = vec![];
+
+        for _ in 0..count {
+            retval.push( Self {
+                cue_point_id : rdr.read_u32::<LittleEndian>()?,
+                frame : rdr.read_u32::<LittleEndian>()?,
+                chunk_id : rdr.read_fourcc()?,
+                chunk_start : rdr.read_u32::<LittleEndian>()?,
+                block_start : rdr.read_u32::<LittleEndian>()?,
+                frame_offset : rdr.read_u32::<LittleEndian>()?
+            })
+        }
+
+        Ok( retval )
+    }
+}
+
+#[derive(Clone, Debug)]
+struct RawLabel {
+    cue_point_id : u32,
+    text : Vec<u8>
+}
+
+impl RawLabel {
+    fn read_from(data : &[u8]) -> Result<Self, Error> {
+        let mut rdr = Cursor::new(data);
+        let length = data.len();
+
+        Ok( Self {
+            cue_point_id : rdr.read_u32::<LittleEndian>()?,
+            text : {
+                let mut buf = vec![0u8; (length - 4) as usize ];
+                rdr.read_exact(&mut buf)?;
+                if buf.len() % 2 == 1 { rdr.read_u8()?; };
+                buf
+               // String::from_utf8(buf).unwrap_or(String::from("<TEXT ENCODING ERROR>"))
+            }
+        })
+    }
+}
+
+#[derive(Clone, Debug)]
+struct RawNote {
+    cue_point_id : u32,
+    text : Vec<u8>
+}
+
+impl RawNote {
+    fn read_from(data : &[u8]) -> Result<Self, Error> {
+        let mut rdr = Cursor::new(data);
+        let length = data.len();
+
+        Ok( Self {
+            cue_point_id : rdr.read_u32::<LittleEndian>()?,
+            text : {
+                let mut buf = vec![0u8; (length - 4) as usize ];
+                rdr.read_exact(&mut buf)?;
+                if length % 2 == 1 { rdr.read_u8()?; };
+                buf
+                //String::from_utf8(buf).unwrap_or(String::from("<TEXT ENCODING ERROR>"))
+            }
+        })
+    }
+}
+
+#[derive(Clone, Debug)]
+struct RawLtxt { 
+    cue_point_id : u32,
+    frame_length : u32,
+    purpose : FourCC,
+    country : u16,
+    language : u16,
+    dialect : u16,
+    code_page : u16,
+    text: Option<Vec<u8>>
+}
+
+impl RawLtxt {
+    fn read_from(data : &[u8]) -> Result<Self, Error> {
+        let mut rdr = Cursor::new(data);
+        let length = data.len();
+
+        Ok( Self {
+            cue_point_id : rdr.read_u32::<LittleEndian>()?,
+            frame_length : rdr.read_u32::<LittleEndian>()?,
+            purpose : rdr.read_fourcc()?,
+            country : rdr.read_u16::<LittleEndian>()?,
+            language : rdr.read_u16::<LittleEndian>()?,
+            dialect : rdr.read_u16::<LittleEndian>()?,
+            code_page : rdr.read_u16::<LittleEndian>()?,
+            text : {
+                if length - 20 > 0 {
+                    let mut buf = vec![0u8; (length - 20) as usize];
+                    rdr.read_exact(&mut buf)?;
+                    if length % 2 == 1 { rdr.read_u8()?; };
+                    Some( buf )
+                    //Some( String::from_utf8(buf).unwrap_or(String::from("<TEXT ENCODING ERROR>")) )
+                } else {
+                    None
+                }
+            }
+        })
+    }
+}
+
+#[derive(Clone, Debug)]
+enum RawAdtlMember {
+    Label(RawLabel),
+    Note(RawNote),
+    LabeledText(RawLtxt),
+    Unrecognized(FourCC)
+}
+
+impl RawAdtlMember {
+    fn collect_from(chunk : &[u8]) -> Result<Vec<RawAdtlMember>,Error> {
+        let chunks = collect_list_form(chunk)?;
+        let mut retval : Vec<RawAdtlMember> = vec![];
+
+        for chunk in chunks.iter() {
+            retval.push( 
+                match chunk.signature {
+                    LABL_SIG => RawAdtlMember::Label( RawLabel::read_from(&chunk.contents)? ),
+                    NOTE_SIG => RawAdtlMember::Note( RawNote::read_from(&chunk.contents)? ),
+                    LTXT_SIG => RawAdtlMember::LabeledText( RawLtxt::read_from(&chunk.contents)? ),
+                    x => RawAdtlMember::Unrecognized(x)
+                }
+            )
+        }
+        Ok( retval )
+    }
+}
+
+trait AdtlMemberSearch {
+    fn labels_for_cue_point(&self, id: u32) -> Vec<&RawLabel>;
+    fn notes_for_cue_point(&self, id : u32) -> Vec<&RawNote>;
+    fn ltxt_for_cue_point(&self, id: u32) -> Vec<&RawLtxt>;
+}
+
+impl AdtlMemberSearch for Vec<RawAdtlMember> {
+
+    fn labels_for_cue_point(&self, id: u32) -> Vec<&RawLabel> {
+        self.iter().filter_map(|item| {
+            match item {
+                RawAdtlMember::Label(x) if x.cue_point_id == id => Some(x),
+                _ => None
+            }
+        })
+        .collect()
+    }
+    
+    fn notes_for_cue_point(&self, id: u32) -> Vec<&RawNote> { 
+        self.iter().filter_map(|item| {
+            match item {
+                RawAdtlMember::Note(x) if x.cue_point_id == id => Some(x),
+                _ => None
+            }
+        })
+        .collect()  
+    }
+
+    fn ltxt_for_cue_point(&self, id: u32) -> Vec<&RawLtxt> {
+        self.iter().filter_map(|item| {
+            match item {
+                RawAdtlMember::LabeledText(x) if x.cue_point_id == id => Some(x),
+                _ => None
+            }
+        })
+        .collect()
+    }
+}
+
+/// A cue point recorded in the `cue` and `adtl` metadata.
+/// 
+/// 
+pub struct Cue {
+
+    /// Unique numeric identifier for this cue
+    pub ident : u32,
+
+    /// The time of this marker
+    pub frame : u32,
+
+    /// The length of this marker, if it is a range
+    pub length : Option<u32>,
+
+    /// The text "label"/name of this marker if provided
+    pub label : Option<String>,
+
+    /// The text "note"/comment of this marker if provided
+    pub note : Option<String>
+}
+
+
+impl Cue {
+
+    pub fn collect_from(cue_chunk : &[u8], adtl_chunk : Option<&[u8]>) -> Result<Vec<Cue>, Error> {
+        let raw_cues = RawCue::read_from(cue_chunk)?;
+        let raw_adtl : Vec<RawAdtlMember>;
+
+        if let Some(adtl) = adtl_chunk {
+            raw_adtl = RawAdtlMember::collect_from(adtl)?;
+        } else {
+            raw_adtl = vec![];
+        }
+
+        Ok( 
+            raw_cues.iter()
+            .map(|i| {
+                Cue {
+                    ident : i.cue_point_id,
+                    frame : i.frame,
+                    length: {
+                        raw_adtl.ltxt_for_cue_point(i.cue_point_id).first().map(|x| x.frame_length)
+                    },
+                    label: {
+                        raw_adtl.labels_for_cue_point(i.cue_point_id).iter()
+                            .filter_map(|x| str::from_utf8(&x.text).ok())
+                            .map(|s| String::from(s))
+                            .next()
+                    },
+                    note : {
+                        raw_adtl.notes_for_cue_point(i.cue_point_id).iter()
+                            .filter_map(|x| str::from_utf8(&x.text).ok())
+                            .map(|s| String::from(s))
+                            .next()
+                    }
+                }
+            }).collect() 
+        )
+    }
+
+}