franklin_crypto/plonk/circuit/
utils.rs

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
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
use crate::bellman::pairing::ff::*;
use crate::bellman::SynthesisError;

pub fn u16_to_fe<F: PrimeField>(value: u16) -> F {
    u64_to_fe(value as u64)
}

pub fn u32_to_fe<F: PrimeField>(value: u32) -> F {
    u64_to_fe(value as u64)
}

pub fn u64_to_fe<F: PrimeField>(value: u64) -> F {
    let mut repr = F::Repr::default();
    repr.as_mut()[0] = value;

    F::from_repr(repr).unwrap()
}

pub fn u128_to_fe<F: PrimeField>(value: u128) -> F {
    let mut repr = F::Repr::default();
    repr.as_mut()[0] = value as u64;
    repr.as_mut()[1] = (value >> 64) as u64;

    F::from_repr(repr).unwrap()
}

pub fn u64_to_le_bits(value: u64, limit: Option<usize>) -> Vec<bool> {
    let limit = if let Some(limit) = limit { limit } else { 64 };

    let mut bits: Vec<bool> = BitIterator::new(&[value]).collect();
    bits.reverse();
    bits.truncate(limit);

    bits
}

pub fn fe_to_le_bits<F: PrimeField>(value: F, limit: Option<usize>) -> Vec<bool> {
    let limit = if let Some(limit) = limit { limit } else { F::NUM_BITS as usize };

    let mut bits: Vec<bool> = BitIterator::new(&value.into_repr()).collect();
    bits.reverse();
    bits.truncate(limit);

    bits
}
#[derive(Clone, Copy)]
struct ZeroPaddingBuffer<'a>(&'a [u8]);

impl<'a> std::io::Read for ZeroPaddingBuffer<'a> {
    fn read(&mut self, _buf: &mut [u8]) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_vectored(&mut self, _bufs: &mut [std::io::IoSliceMut<'_>]) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_to_end(&mut self, _buf: &mut Vec<u8>) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_to_string(&mut self, _buf: &mut String) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_exact(&mut self, buf: &mut [u8]) -> std::io::Result<()> {
        let bytes_available = self.0.len();
        let len = buf.len();
        if bytes_available >= len {
            let (to_read, leftover) = self.0.split_at(len);
            buf.copy_from_slice(&*to_read);

            self.0 = leftover;
        } else {
            buf[..bytes_available].copy_from_slice(&self.0);
            for b in buf[bytes_available..].iter_mut() {
                *b = 0u8;
            }
            self.0 = &[];
        }
        Ok(())
    }
    fn by_ref(&mut self) -> &mut Self
    where
        Self: Sized,
    {
        self
    }
    fn bytes(self) -> std::io::Bytes<Self>
    where
        Self: Sized,
    {
        unimplemented!()
    }
    fn chain<R: std::io::Read>(self, _next: R) -> std::io::Chain<Self, R>
    where
        Self: Sized,
    {
        unimplemented!()
    }
    fn take(self, _limit: u64) -> std::io::Take<Self>
    where
        Self: Sized,
    {
        unimplemented!()
    }
}

#[derive(Clone, Copy)]
struct ZeroPrePaddingBuffer<'a>(&'a [u8], usize);

impl<'a> std::io::Read for ZeroPrePaddingBuffer<'a> {
    fn read(&mut self, _buf: &mut [u8]) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_vectored(&mut self, _bufs: &mut [std::io::IoSliceMut<'_>]) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_to_end(&mut self, _buf: &mut Vec<u8>) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_to_string(&mut self, _buf: &mut String) -> std::io::Result<usize> {
        unimplemented!()
    }
    fn read_exact(&mut self, buf: &mut [u8]) -> std::io::Result<()> {
        let bytes_available = self.0.len();
        let padding_available = self.1;
        let len = buf.len();
        if padding_available >= len {
            self.1 -= len;
            for b in buf.iter_mut() {
                *b = 0u8;
            }
        } else {
            let (dst_to_zero, dst_to_read_to) = buf.split_at_mut(self.1);
            self.1 = 0;
            for b in dst_to_zero.iter_mut() {
                *b = 0u8;
            }
            let len = dst_to_read_to.len();
            if len >= bytes_available {
                let (to_read, leftover) = self.0.split_at(len);
                dst_to_read_to.copy_from_slice(&*to_read);
                self.0 = leftover;
            } else {
                let midpoint = len - bytes_available;
                dst_to_read_to[midpoint..].copy_from_slice(&self.0);
                for b in dst_to_read_to[..midpoint].iter_mut() {
                    *b = 0u8;
                }
                self.0 = &[];
            }
        }

        Ok(())
    }
    fn by_ref(&mut self) -> &mut Self
    where
        Self: Sized,
    {
        self
    }
    fn bytes(self) -> std::io::Bytes<Self>
    where
        Self: Sized,
    {
        unimplemented!()
    }
    fn chain<R: std::io::Read>(self, _next: R) -> std::io::Chain<Self, R>
    where
        Self: Sized,
    {
        unimplemented!()
    }
    fn take(self, _limit: u64) -> std::io::Take<Self>
    where
        Self: Sized,
    {
        unimplemented!()
    }
}

#[track_caller]
pub fn pack_be_bytes_to_fe<F: PrimeField>(bytes: &[u8]) -> Result<F, SynthesisError> {
    let mut repr = F::zero().into_repr();
    let expected_len = repr.as_ref().len() * 8;
    assert!(bytes.len() <= expected_len);
    let padding = expected_len - bytes.len();
    let buff = ZeroPrePaddingBuffer(&bytes, padding);
    repr.read_be(buff).map_err(|_| SynthesisError::Unsatisfiable)?;
    let el = F::from_repr(repr).map_err(|_| SynthesisError::Unsatisfiable)?;

    Ok(el)
}

#[track_caller]
pub fn pack_le_bytes_to_fe<F: PrimeField>(bytes: &[u8]) -> Result<F, SynthesisError> {
    let buff = ZeroPaddingBuffer(&bytes);
    let mut repr = F::zero().into_repr();
    repr.read_le(buff).map_err(|_| SynthesisError::Unsatisfiable)?;
    let el = F::from_repr(repr).map_err(|_| SynthesisError::Unsatisfiable)?;

    Ok(el)
}

#[track_caller]
pub fn fe_to_be_bytes<F: PrimeField>(el: &F) -> Result<Vec<u8>, SynthesisError> {
    let mut buffer = vec![];
    let repr = el.into_repr();
    repr.write_be(&mut buffer).map_err(|_| SynthesisError::Unsatisfiable)?;

    Ok(buffer)
}

#[track_caller]
pub fn fe_to_le_bytes<F: PrimeField>(el: &F) -> Result<Vec<u8>, SynthesisError> {
    let mut buffer = vec![];
    let repr = el.into_repr();
    repr.write_le(&mut buffer).map_err(|_| SynthesisError::Unsatisfiable)?;

    Ok(buffer)
}

pub fn words_to_msb_first_bits(el: &[u64]) -> Vec<bool> {
    use crate::bellman::pairing::ff::BitIterator;
    let mut result: Vec<_> = BitIterator::new(el).collect();

    let mut first_true_index = 0;
    for (i, b) in result.iter().enumerate() {
        if *b {
            first_true_index = i;
            break;
        }
    }
    let _ = result.drain(0..first_true_index);

    result
}

pub fn words_to_lsb_first_bits(el: &[u64]) -> Vec<bool> {
    let mut result = words_to_msb_first_bits(el);
    result.reverse();

    result
}

pub fn fe_to_msb_first_bits<F: PrimeField>(el: &F) -> Vec<bool> {
    use crate::bellman::pairing::ff::BitIterator;
    let repr = el.into_repr();
    let mut result: Vec<_> = BitIterator::new(repr.as_ref()).collect();
    let skip = result.len() - (F::NUM_BITS as usize);
    let _ = result.drain(0..skip);

    result
}

pub fn fe_to_lsb_first_bits<F: PrimeField>(el: &F) -> Vec<bool> {
    let mut result = fe_to_msb_first_bits(el);
    result.reverse();

    result
}

use crate::bellman::pairing::Engine;
use crate::bellman::plonk::better_better_cs::cs::ConstraintSystem;

pub fn is_selector_specialized_gate<E: Engine, CS: ConstraintSystem<E>>() -> bool {
    use bellman::plonk::better_better_cs::cs::GateInternal;
    use bellman::plonk::better_better_cs::gates::selector_optimized_with_d_next::SelectorOptimizedWidth4MainGateWithDNext;
    use std::any::Any;

    Any::type_id(&CS::MainGate::default()) == Any::type_id(&SelectorOptimizedWidth4MainGateWithDNext)
}

pub fn is_naive_main_gate<E: Engine, CS: ConstraintSystem<E>>() -> bool {
    use bellman::plonk::better_better_cs::cs::GateInternal;
    use bellman::plonk::better_better_cs::cs::PlonkConstraintSystemParams;
    use bellman::plonk::better_better_cs::gates::naive_main_gate::NaiveMainGate;
    use std::any::Any;
    Any::type_id(&CS::MainGate::default()) == Any::type_id(&NaiveMainGate)
}