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Diffstat (limited to 'src/serde.rs')
-rw-r--r-- | src/serde.rs | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/serde.rs b/src/serde.rs new file mode 100644 index 0000000..4fb18e9 --- /dev/null +++ b/src/serde.rs @@ -0,0 +1,91 @@ +extern crate serde; + +use core::fmt; +use core::marker::PhantomData; + +use self::serde::de::{Deserialize, Deserializer, MapAccess, Visitor}; +use self::serde::ser::{Serialize, SerializeMap, Serializer}; + +use super::{Entry, Slab}; + +impl<T> Serialize for Slab<T> +where + T: Serialize, +{ + fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> + where + S: Serializer, + { + let mut map_serializer = serializer.serialize_map(Some(self.len()))?; + for (key, value) in self { + map_serializer.serialize_key(&key)?; + map_serializer.serialize_value(value)?; + } + map_serializer.end() + } +} + +struct SlabVisitor<T>(PhantomData<T>); + +impl<'de, T> Visitor<'de> for SlabVisitor<T> +where + T: Deserialize<'de>, +{ + type Value = Slab<T>; + + fn expecting(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + write!(fmt, "a map") + } + + fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error> + where + A: MapAccess<'de>, + { + let mut slab = Slab::with_capacity(map.size_hint().unwrap_or(0)); + + // same as FromIterator impl + let mut vacant_list_broken = false; + while let Some((key, value)) = map.next_entry()? { + if key < slab.entries.len() { + // iterator is not sorted, might need to recreate vacant list + if let Entry::Vacant(_) = slab.entries[key] { + vacant_list_broken = true; + slab.len += 1; + } + // if an element with this key already exists, replace it. + // This is consisent with HashMap and BtreeMap + slab.entries[key] = Entry::Occupied(value); + } else { + // insert holes as necessary + while slab.entries.len() < key { + // add the entry to the start of the vacant list + let next = slab.next; + slab.next = slab.entries.len(); + slab.entries.push(Entry::Vacant(next)); + } + slab.entries.push(Entry::Occupied(value)); + slab.len += 1; + } + } + if slab.len == slab.entries.len() { + // no vacant enries, so next might not have been updated + slab.next = slab.entries.len(); + } else if vacant_list_broken { + slab.recreate_vacant_list(); + } + + Ok(slab) + } +} + +impl<'de, T> Deserialize<'de> for Slab<T> +where + T: Deserialize<'de>, +{ + fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> + where + D: Deserializer<'de>, + { + deserializer.deserialize_map(SlabVisitor(PhantomData)) + } +} |