miden_core/advice/
map.rs

1use alloc::{
2    collections::{
3        BTreeMap,
4        btree_map::{Entry, IntoIter},
5    },
6    sync::Arc,
7    vec::Vec,
8};
9
10#[cfg(feature = "serde")]
11use serde::{Deserialize, Serialize};
12
13use crate::{
14    Felt, WORD_SIZE, Word,
15    serde::{ByteReader, ByteWriter, Deserializable, DeserializationError, Serializable},
16};
17
18// ADVICE MAP
19// ================================================================================================
20
21/// Defines a set of non-deterministic (advice) inputs which the VM can access by their keys.
22///
23/// Each key maps to one or more field element. To access the elements, the VM can move the values
24/// associated with a given key onto the advice stack using `adv.push_mapval` instruction. The VM
25/// can also insert new values into the advice map during execution.
26///
27/// This type is a policy-free container. Execution-specific size limits for live advice map state
28/// are enforced by the processor's `AdviceProvider`, which owns the active execution options and
29/// live resource accounting.
30#[derive(Debug, Clone, Default, PartialEq, Eq)]
31#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
32#[cfg_attr(feature = "serde", serde(transparent))]
33#[cfg_attr(
34    all(feature = "arbitrary", test),
35    miden_test_serde_macros::serde_test(binary_serde(true))
36)]
37pub struct AdviceMap(BTreeMap<Word, Arc<[Felt]>>);
38
39/// Pair representing a key-value entry in an [`AdviceMap`]
40type MapEntry = (Word, Arc<[Felt]>);
41
42impl AdviceMap {
43    /// Returns the values associated with given key.
44    pub fn get(&self, key: &Word) -> Option<&Arc<[Felt]>> {
45        self.0.get(key)
46    }
47
48    /// Returns true if the key has a corresponding value in the map.
49    pub fn contains_key(&self, key: &Word) -> bool {
50        self.0.contains_key(key)
51    }
52
53    /// Inserts a value, returning the previous value if the key was already set.
54    pub fn insert(&mut self, key: Word, value: impl Into<Arc<[Felt]>>) -> Option<Arc<[Felt]>> {
55        self.0.insert(key, value.into())
56    }
57
58    /// Removes the value associated with the key and returns the removed element.
59    pub fn remove(&mut self, key: &Word) -> Option<Arc<[Felt]>> {
60        self.0.remove(key)
61    }
62
63    /// Return an iteration over all entries in the map.
64    pub fn iter(&self) -> impl Iterator<Item = (&Word, &Arc<[Felt]>)> {
65        self.0.iter()
66    }
67
68    /// Returns the number of key value pairs in the advice map.
69    pub fn len(&self) -> usize {
70        self.0.len()
71    }
72
73    /// Returns true if the advice map is empty.
74    pub fn is_empty(&self) -> bool {
75        self.0.is_empty()
76    }
77
78    /// Returns the total number of field elements stored in this advice map's keys and values.
79    ///
80    /// Each key is a word, so every entry contributes [`WORD_SIZE`] key elements plus the number
81    /// of value elements associated with that key. Returns `None` if the count overflows `usize`.
82    pub fn total_element_count(&self) -> Option<usize> {
83        self.0.values().try_fold(0usize, |total, values| {
84            WORD_SIZE
85                .checked_add(values.len())
86                .and_then(|entry_elements| total.checked_add(entry_elements))
87        })
88    }
89
90    /// Gets the given key's corresponding entry in the map for in-place manipulation.
91    pub fn entry(&mut self, key: Word) -> Entry<'_, Word, Arc<[Felt]>> {
92        self.0.entry(key)
93    }
94
95    /// Merges all entries from the given [`AdviceMap`] into the current advice map.
96    ///
97    /// If an entry from the new map already exists with the same key but different value,
98    /// an error is returned containing the existing entry along with the value that would replace
99    /// it. The current map remains unchanged.
100    pub fn merge(&mut self, other: &Self) -> Result<(), (MapEntry, Arc<[Felt]>)> {
101        if let Some(conflict) = self.find_conflicting_entry(other) {
102            Err(conflict)
103        } else {
104            self.merge_new(other);
105            Ok(())
106        }
107    }
108
109    /// Merges entries from `other`, but only for keys not already present in `self`.
110    fn merge_new(&mut self, other: &Self) {
111        for (key, value) in other.iter() {
112            self.0.entry(*key).or_insert_with(|| value.clone());
113        }
114    }
115
116    /// Finds the first key that exists in both `self` and `other` with different values.
117    ///
118    /// # Returns
119    /// - `Some` containing the conflicting key, its value from `self`, and the value from `other`.
120    /// - `None` if there are no conflicting values.
121    fn find_conflicting_entry(&self, other: &Self) -> Option<(MapEntry, Arc<[Felt]>)> {
122        for (key, new_value) in other.iter() {
123            if let Some(existing_value) = self.get(key)
124                && existing_value != new_value
125            {
126                // Found a conflict.
127                return Some(((*key, existing_value.clone()), new_value.clone()));
128            }
129        }
130        // No conflicts found.
131        None
132    }
133}
134
135impl From<BTreeMap<Word, Arc<[Felt]>>> for AdviceMap {
136    fn from(value: BTreeMap<Word, Arc<[Felt]>>) -> Self {
137        Self(value)
138    }
139}
140
141impl From<BTreeMap<Word, Vec<Felt>>> for AdviceMap {
142    fn from(value: BTreeMap<Word, Vec<Felt>>) -> Self {
143        value.into_iter().collect()
144    }
145}
146
147impl IntoIterator for AdviceMap {
148    type Item = (Word, Arc<[Felt]>);
149    type IntoIter = IntoIter<Word, Arc<[Felt]>>;
150
151    fn into_iter(self) -> Self::IntoIter {
152        self.0.into_iter()
153    }
154}
155
156impl<V> FromIterator<(Word, V)> for AdviceMap
157where
158    V: Into<Arc<[Felt]>>,
159{
160    fn from_iter<I>(iter: I) -> Self
161    where
162        I: IntoIterator<Item = (Word, V)>,
163    {
164        iter.into_iter()
165            .map(|(key, value)| (key, value.into()))
166            .collect::<BTreeMap<Word, Arc<[Felt]>>>()
167            .into()
168    }
169}
170
171impl<V> Extend<(Word, V)> for AdviceMap
172where
173    V: Into<Arc<[Felt]>>,
174{
175    fn extend<I>(&mut self, iter: I)
176    where
177        I: IntoIterator<Item = (Word, V)>,
178    {
179        self.0.extend(iter.into_iter().map(|(key, value)| (key, value.into())))
180    }
181}
182
183impl Serializable for AdviceMap {
184    fn write_into<W: ByteWriter>(&self, target: &mut W) {
185        target.write_usize(self.0.len());
186        for (key, values) in self.0.iter() {
187            target.write((key, values.to_vec()));
188        }
189    }
190}
191
192impl Deserializable for AdviceMap {
193    fn read_from<R: ByteReader>(source: &mut R) -> Result<Self, DeserializationError> {
194        let mut map = BTreeMap::new();
195        let count = source.read_usize()?;
196        for _ in 0..count {
197            let (key, values): (Word, Vec<Felt>) = source.read()?;
198            map.insert(key, Arc::from(values));
199        }
200        Ok(Self(map))
201    }
202}
203
204#[cfg(test)]
205mod tests {
206    use super::*;
207
208    #[test]
209    fn test_advice_map_serialization() {
210        let mut map1 = AdviceMap::default();
211        map1.insert(Word::default(), vec![Felt::from_u32(1), Felt::from_u32(2)]);
212
213        let bytes = map1.to_bytes();
214
215        let map2 = AdviceMap::read_from_bytes(&bytes).unwrap();
216
217        assert_eq!(map1, map2);
218    }
219}
miden_core/advice/map.rs

miden_core/advice/
map.rs
