1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
use crate::prelude::*;
use std::collections::HashMap;
use std::hash::{BuildHasher, Hash};
use std::vec::IntoIter;

#[cfg(feature = "encode")]
impl<K: Encodable, V: Encodable, S: Default + BuildHasher> Encodable for HashMap<K, V, S> {
    type EncoderArray = HashMapArrayEncoder<K::EncoderArray, V::EncoderArray, S>;
    fn encode_root<O: EncodeOptions>(&self, stream: &mut EncoderStream<'_, O>) -> RootTypeId {
        profile!("HashMap encode_root");

        encode_usize(self.len(), stream);
        match self.len() {
            0 => {}
            1 => {
                for key in self.keys() {
                    stream.encode_with_id(|stream| key.encode_root(stream));
                }
                for value in self.values() {
                    stream.encode_with_id(|stream| value.encode_root(stream));
                }
            }
            _ => {
                let mut keys_encoder = K::EncoderArray::default();
                for key in self.keys() {
                    keys_encoder.buffer_one(key);
                }
                stream.encode_with_id(|stream| keys_encoder.flush(stream));
                // TODO: Verify that iterating keys and values is always the same order!
                let mut values_encoder = V::EncoderArray::default();
                for value in self.values() {
                    values_encoder.buffer_one(value);
                }
                stream.encode_with_id(|stream| values_encoder.flush(stream));
            }
        }

        RootTypeId::Map
    }
}

#[cfg(feature = "decode")]
impl<K: Decodable + Hash + Eq + Send, V: Decodable + Send, S: Default + BuildHasher> Decodable for HashMap<K, V, S>
where
    // Overly verbose because of `?` requiring `From` See also ec4fa3ba-def5-44eb-9065-e80b59530af6
    DecodeError: From<<<K as Decodable>::DecoderArray as DecoderArray>::Error>,
    // Overly verbose because of `?` requiring `From` See also ec4fa3ba-def5-44eb-9065-e80b59530af6
    DecodeError: From<<<V as Decodable>::DecoderArray as DecoderArray>::Error>,
{
    type DecoderArray = Option<HashMapArrayDecoder<K::DecoderArray, V::DecoderArray, S>>;
    fn decode(sticks: DynRootBranch<'_>, options: &impl DecodeOptions) -> DecodeResult<Self> {
        profile!("HashMap Decodable::decode");

        let mut v = Default::default(); // TODO: (Performance) Capacity
        match sticks {
            DynRootBranch::Map0 => Ok(v),
            DynRootBranch::Map1 { key, value } => {
                let (key, value) = parallel(move || K::decode(*key, options), move || V::decode(*value, options), options);
                v.insert(key?, value?);
                Ok(v)
            }
            DynRootBranch::Map { len, keys, values } => {
                let (keys, values) = parallel(|| K::DecoderArray::new(keys, options), || V::DecoderArray::new(values, options), options);
                let mut keys = keys?;
                let mut values = values?;
                for _ in 0..len {
                    if v.insert(keys.decode_next()?, values.decode_next()?).is_some() {
                        return Err(DecodeError::InvalidFormat);
                    }
                }
                Ok(v)
            }
            _ => Err(DecodeError::SchemaMismatch),
        }
    }
}

#[cfg(feature = "encode")]
#[derive(Debug, Default)]
pub struct HashMapArrayEncoder<K, V, S> {
    len: <u64 as Encodable>::EncoderArray,
    items: Option<(K, V)>,
    _marker: Unowned<S>,
}

#[cfg(feature = "decode")]
pub struct HashMapArrayDecoder<K, V, S> {
    len: IntoIter<u64>,
    keys: K,
    values: V,
    _marker: Unowned<S>,
}

#[cfg(feature = "encode")]
impl<K: Encodable, V: Encodable, S: Default + BuildHasher> EncoderArray<HashMap<K, V, S>> for HashMapArrayEncoder<K::EncoderArray, V::EncoderArray, S> {
    fn buffer_one<'a, 'b: 'a>(&'a mut self, value: &'b HashMap<K, V, S>) {
        profile!("HashMap EncoderArray::buffer");
        self.len.buffer_one(&(value.len() as u64));
        let (keys, values) = self.items.get_or_insert_with(Default::default);
        for (key, value) in value.iter() {
            keys.buffer_one(key);
            values.buffer_one(value);
        }
    }
    fn flush<O: EncodeOptions>(self, stream: &mut EncoderStream<'_, O>) -> ArrayTypeId {
        profile!("HashMap EncoderArray::flush");
        let Self { len, items, _marker } = self;
        if let Some((keys, values)) = items {
            stream.encode_with_id(|stream| len.flush(stream));
            stream.encode_with_id(|stream| keys.flush(stream));
            stream.encode_with_id(|stream| values.flush(stream));
        } else {
            stream.encode_with_id(|_| ArrayTypeId::Void);
        }
        ArrayTypeId::Map
    }
}

#[cfg(feature = "decode")]
impl<K: DecoderArray, V: DecoderArray, S: Default + BuildHasher> DecoderArray for Option<HashMapArrayDecoder<K, V, S>>
where
    K::Decode: Hash + Eq,
    // Overly verbose because of `?` requiring `From` See also ec4fa3ba-def5-44eb-9065-e80b59530af6
    DecodeError: From<K::Error>,
    // Overly verbose because of `?` requiring `From` See also ec4fa3ba-def5-44eb-9065-e80b59530af6
    DecodeError: From<V::Error>,
{
    type Decode = HashMap<K::Decode, V::Decode, S>;
    type Error = DecodeError;

    fn new(sticks: DynArrayBranch<'_>, options: &impl DecodeOptions) -> DecodeResult<Self> {
        profile!("HashMap DecoderArray::new");

        match sticks {
            DynArrayBranch::Map0 => Ok(None),
            DynArrayBranch::Map { len, keys, values } => {
                let (keys, (values, len)) = parallel(
                    || K::new(*keys, options),
                    || {
                        parallel(
                            || V::new(*values, options),
                            || <<u64 as Decodable>::DecoderArray as DecoderArray>::new(*len, options),
                            options,
                        )
                    },
                    options,
                );
                let keys = keys?;
                let values = values?;
                let len = len?;
                Ok(Some(HashMapArrayDecoder {
                    len,
                    keys,
                    values,
                    _marker: Unowned::new(),
                }))
            }
            _ => Err(DecodeError::SchemaMismatch),
        }
    }
    fn decode_next(&mut self) -> Result<Self::Decode, Self::Error> {
        if let Some(inner) = self {
            let len = inner.len.decode_next_infallible();
            let mut result = <Self::Decode as Default>::default(); // TODO: (Performance) capacity
            for _ in 0..len {
                let key = inner.keys.decode_next()?;
                let value = inner.values.decode_next()?;
                // TODO: decode_next was made infallable for performance reasons,
                // but duplicate keys would seem a reason to fail. Ideally this could
                // have a Result<T, !> and perform well in the future.
                if result.insert(key, value).is_some() {
                    return Err(DecodeError::InvalidFormat);
                };
            }
            Ok(result)
        } else {
            Ok(Default::default())
        }
    }
}