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

// Copyright (C) 2019-2023 Aleo Systems Inc.
// This file is part of the snarkVM library.

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

mod assignment;
pub use assignment::*;

mod constraint_counter;
pub use constraint_counter::*;

mod constraint_system;
pub use constraint_system::{ConstraintSynthesizer, ConstraintSystem};

mod constraint_variable;
pub use constraint_variable::*;

pub mod errors;
pub use errors::*;

mod linear_combination;
pub use linear_combination::*;

mod namespace;
pub use namespace::*;

mod optional_vec;
pub use optional_vec::*;

mod test_constraint_system;
pub use test_constraint_system::{Fr, TestConstraintSystem};

mod test_constraint_checker;
pub use test_constraint_checker::TestConstraintChecker;

use snarkvm_utilities::serialize::*;

use core::cmp::Ordering;

/// Represents a variable in a constraint system.
#[derive(PartialOrd, Ord, PartialEq, Eq, Copy, Clone, Debug, Hash)]
pub struct Variable(Index);

impl Variable {
    /// This constructs a variable with an arbitrary index.
    /// Circuit implementations are not recommended to use this.
    pub fn new_unchecked(idx: Index) -> Variable {
        Variable(idx)
    }

    /// This returns the index underlying the variable.
    /// Circuit implementations are not recommended to use this.
    pub fn get_unchecked(&self) -> Index {
        self.0
    }
}

/// Represents the index of either a public variable (input) or a private variable (auxiliary).
#[derive(Copy, Clone, PartialEq, Debug, Eq, Hash)]
pub enum Index {
    /// Index of an public variable.
    Public(usize),
    /// Index of an private variable.
    Private(usize),
}

impl PartialOrd for Index {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl Ord for Index {
    fn cmp(&self, other: &Self) -> Ordering {
        match (self, other) {
            (Index::Public(ref idx1), Index::Public(ref idx2))
            | (Index::Private(ref idx1), Index::Private(ref idx2)) => idx1.cmp(idx2),
            (Index::Public(_), Index::Private(_)) => Ordering::Less,
            (Index::Private(_), Index::Public(_)) => Ordering::Greater,
        }
    }
}

impl CanonicalSerialize for Index {
    #[inline]
    fn serialize_with_mode<W: Write>(&self, mut writer: W, _: Compress) -> Result<(), SerializationError> {
        let (is_public, inner) = match *self {
            Index::Public(inner) => (true, inner),
            Index::Private(inner) => (false, inner),
        };
        // we use uncompressed here because the serialization of bool and usize
        // don't change whether we use uncompressed or not.
        is_public.serialize_uncompressed(&mut writer)?;
        inner.serialize_uncompressed(&mut writer)?;
        Ok(())
    }

    #[inline]
    fn serialized_size(&self, _: Compress) -> usize {
        // we use uncompressed here because the serialization of bool and usize
        // don't change whether we use uncompressed or not.
        0usize.uncompressed_size() + true.uncompressed_size()
    }
}

impl Valid for Index {
    fn check(&self) -> Result<(), SerializationError> {
        Ok(())
    }
}
impl CanonicalDeserialize for Index {
    #[inline]
    fn deserialize_with_mode<R: Read>(mut reader: R, _: Compress, _: Validate) -> Result<Self, SerializationError> {
        // we use uncompressed here because the serialization of bool and usize
        // don't change whether we use uncompressed or not.
        let is_input = bool::deserialize_uncompressed(&mut reader)?;
        let inner = usize::deserialize_uncompressed(&mut reader)?;
        Ok(if is_input { Index::Public(inner) } else { Index::Private(inner) })
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn serialize_index() {
        serialize_index_test(true);
        serialize_index_test(false);
    }

    fn serialize_index_test(input: bool) {
        let idx = if input { Index::Public(32) } else { Index::Private(32) };

        let mut v = vec![];
        idx.serialize_compressed(&mut v).unwrap();
        let idx2 = Index::deserialize_compressed(&v[..]).unwrap();
        assert_eq!(idx, idx2);
    }
}