preserves/implementations/rust/src/value/encoder.rs

use super::value::{Value, NestedValue, Domain, IOValue, UnwrappedIOValue, Float, Double};
use super::signed_integer::SignedIntegerRepr;
use super::writer::Writer;
use super::packed::PackedWriter;

pub use super::writer::Result;

pub struct Encoder<'a, W: Writer> {
    pub write: &'a mut W,
}

pub fn encode_bytes(v: &IOValue) -> std::io::Result<Vec<u8>> {
    let mut buf: Vec<u8> = Vec::new();
    Encoder::new(&mut PackedWriter(&mut buf)).write(v)?;
    Ok(buf)
}

impl<'a, W: Writer> Encoder<'a, W> {
    pub fn new(write: &'a mut W) -> Self {
        Encoder { write }
    }

    pub fn write(&mut self, v: &IOValue) -> Result<W::Pointer> {
        match v.annotations().maybe_slice() {
            None => self.write_value(v.value()),
            Some(anns) => {
                let mut a = self.write.start_annotation()?;
                for ann in anns {
                    self.write.extend_annotation(&mut a, ann)?;
                }
                let p = self.write_value(v.value())?;
                self.write.end_annotation(a, p)
            }
        }
    }

    pub fn write_value(&mut self, v: &UnwrappedIOValue) -> Result<W::Pointer> {
        match v {
            Value::Boolean(b) => self.write.write_bool(*b),
            Value::Float(Float(f)) => self.write.write_f32(*f),
            Value::Double(Double(d)) => self.write.write_f64(*d),
            Value::SignedInteger(n) => match n.repr() {
                SignedIntegerRepr::I128(i) => self.write.write_i128(*i),
                SignedIntegerRepr::U128(u) => self.write.write_u128(*u),
                SignedIntegerRepr::Big(ref n) => self.write.write_int(n),
            }
            Value::String(ref s) => self.write.write_string(s),
            Value::ByteString(ref bs) => self.write.write_bytes(bs),
            Value::Symbol(ref s) => self.write.write_symbol(s),
            Value::Record(r) => {
                let mut c = self.write.start_record(r.arity() as u64)?;
                let p = self.write(r.label())?;
                self.write.extend_compound(&mut c, p)?;
                for f in r.fields() {
                    let p = self.write(f)?;
                    self.write.extend_compound(&mut c, p)?;
                }
                self.write.end_compound(c)
            }
            Value::Sequence(ref vs) => {
                let mut c = self.write.start_sequence(vs.len() as u64)?;
                for v in vs {
                    let p = self.write(v)?;
                    self.write.extend_compound(&mut c, p)?;
                }
                self.write.end_compound(c)
            }
            Value::Set(ref vs) => {
                let mut c = self.write.start_set(vs.len() as u64)?;
                for v in vs {
                    let p = self.write(v)?;
                    self.write.extend_compound(&mut c, p)?;
                }
                self.write.end_compound(c)
            }
            Value::Dictionary(ref vs) => {
                let mut d = self.write.start_dictionary(vs.len() as u64)?;
                for (k, v) in vs {
                    let p = self.write(k)?;
                    let kp = self.write.extend_dictionary_key(&mut d, p)?;
                    let p = self.write(v)?;
                    self.write.extend_dictionary_value(&mut d, kp, p)?;
                }
                self.write.end_dictionary(d)
            }
            Value::Domain(ref d) => self.write(&d.as_preserves()?)
        }
    }
}