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chore: revert "chore: add safe wrappers around unconstrained function…
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…s" (#7)
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@TomAFrench
TomAFrench authored Mar 4, 2025
1 parent cb355c9 commit d127097
Showing 1 changed file with 85 additions and 103 deletions.
188 changes: 85 additions & 103 deletions src/encoding.nr
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use crate::tables::{
BASE4_PARTIAL_CHOOSE_DECODE_5BIT_TABLE, BASE4_POWERS, BASE4_XOR_DECODE_5BIT_TABLE,
};

unconstrained fn __decompose_e(e: Field) -> [Field; 9] {
unconstrained fn decompose_e(e: Field) -> [Field; 9] {
let mut r: [Field; 9] = [0; 9];
let mut bytes = e.to_le_bytes::<8>();
let b8to14 = bytes[1] & 63;
Expand All @@ -27,37 +27,7 @@ unconstrained fn __decompose_e(e: Field) -> [Field; 9] {
r
}

fn decompose_e(e: Field) -> [Field; 9] {
//Safety: split input into slices with the following bit sizes:
// 8,6,4,6,8,9,7,8,8
// We need to validate the correctness of these slice claims by asserting their sum equals `a`,
// and we also need to validate the bit range of each slice
// (we get an implicit range constraint for free by indexing our BASE4_ENCODE_TABLE lookup tables)
let s = unsafe { __decompose_e(e) };

let mut reconstructed = s[8];
reconstructed *= 256;
reconstructed += s[7];
reconstructed *= 128;
reconstructed += s[6];
reconstructed *= 512;
reconstructed += s[5];
reconstructed *= 256;
reconstructed += s[4];
reconstructed *= 64;
reconstructed += s[3];
reconstructed *= 16;
reconstructed += s[2];
reconstructed *= 64;
reconstructed += s[1];
reconstructed *= 256;
reconstructed += s[0];
assert_eq(reconstructed, e); // 7 gates?

s
}

unconstrained fn __decompose_a(a: Field) -> [Field; 9] {
unconstrained fn decompose_a(a: Field) -> [Field; 9] {
let mut r: [Field; 9] = [0; 9];
let mut bytes = a.to_le_bytes::<8>();
let b24to28 = bytes[3] & 15;
Expand Down Expand Up @@ -100,38 +70,6 @@ unconstrained fn __decompose_a(a: Field) -> [Field; 9] {

}

fn decompose_a(a: Field) -> [Field; 9] {
//Safety: split input into slices with the following bit sizes:
// 8,8,8,4,6,5,9,8,8
// We need to validate the correctness of these slice claims by asserting their sum equals `a`,
// and we also need to validate the bit range of each slice
// (we get an implicit range constraint for free by indexing our BASE4_ENCODE_TABLE lookup tables)
let s = unsafe { __decompose_a(a) };

// 8,8,8,4,6,5,9,8,8
// 7 gates?
let mut reconstructed = s[8];
reconstructed *= 256;
reconstructed += s[7];
reconstructed *= 512;
reconstructed += s[6];
reconstructed *= 32;
reconstructed += s[5];
reconstructed *= 64;
reconstructed += s[4];
reconstructed *= 16;
reconstructed += s[3];
reconstructed *= 256;
reconstructed += s[2];
reconstructed *= 256;
reconstructed += s[1];
reconstructed *= 256;
reconstructed += s[0];
assert_eq(reconstructed, a);

s
}

pub(crate) struct EncodedMajority {
pub(crate) raw: Field,
pub(crate) a: Field,
Expand Down Expand Up @@ -205,42 +143,6 @@ unconstrained fn __decompose_witness(w: Field) -> [Field; 12] {
r
}

fn decompose_witness(w: Field) -> [Field; 12] {
//Safety: split input into slices with the following bit sizes:
// 1, 5, 1, 1, 8, 3, 8, 8, 8, 9, 9, 3
// We need to validate the correctness of these slice claims by asserting their sum equals `w`,
// and we also need to validate the bit range of each slice
// (we get an implicit range constraint for free by indexing our BASE4_ENCODE_TABLE lookup tables)
let s: [Field; 12] = unsafe { __decompose_witness(w) };

let mut reconstructed = s[11];
reconstructed *= 512;
reconstructed += s[10];
reconstructed *= 512;
reconstructed += s[9];
reconstructed *= 256;
reconstructed += s[8];
reconstructed *= 256;
reconstructed += s[7];
reconstructed *= 256;
reconstructed += s[6];
reconstructed *= 8;
reconstructed += s[5];
reconstructed *= 256;
reconstructed += s[4];
reconstructed *= 2;
reconstructed += s[3];
reconstructed *= 2;
reconstructed += s[2];
reconstructed *= 32;
reconstructed += s[1];
reconstructed *= 2;
reconstructed += s[0];
assert_eq(reconstructed, w);

s
}

// unconstrained fn __decompose_w15(w15: Field) -> [Field; 10] {
// let mut r: [Field; 10] = [0; 10];
// let mut bytes = w15.to_le_bytes::<8>();
Expand Down Expand Up @@ -361,7 +263,37 @@ fn decompose_witness(w: Field) -> [Field; 12] {
// }

pub(crate) fn encode_message_extension(w: Field) -> EncodedWitness {
let s: [Field; 12] = decompose_witness(w);
//Safety: split input into slices with the following bit sizes:
// 1, 5, 1, 1, 8, 3, 8, 8, 8, 9, 9, 3
// We need to validate the correctness of these slice claims by asserting their sum equals `w`,
// and we also need to validate the bit range of each slice
// (we get an implicit range constraint for free by indexing our BASE4_ENCODE_TABLE lookup tables)
let s: [Field; 12] = unsafe { __decompose_witness(w) };

let mut reconstructed = s[11];
reconstructed *= 512;
reconstructed += s[10];
reconstructed *= 512;
reconstructed += s[9];
reconstructed *= 256;
reconstructed += s[8];
reconstructed *= 256;
reconstructed += s[7];
reconstructed *= 256;
reconstructed += s[6];
reconstructed *= 8;
reconstructed += s[5];
reconstructed *= 256;
reconstructed += s[4];
reconstructed *= 2;
reconstructed += s[3];
reconstructed *= 2;
reconstructed += s[2];
reconstructed *= 32;
reconstructed += s[1];
reconstructed *= 2;
reconstructed += s[0];
assert_eq(reconstructed, w);

let mut base4_encoded_slices: [Field; 12] = [0; 12];
// 1, 5, 1, 1, 8, 3, 8, 8, 8, 9, 9, 3
Expand Down Expand Up @@ -434,7 +366,31 @@ pub(crate) fn encode_message_extension(w: Field) -> EncodedWitness {
}

pub(crate) fn encode_e(e: Field) -> EncodedChoose {
let s = decompose_e(e);
//Safety: split input into slices with the following bit sizes:
// 8,6,4,6,8,9,7,8,8
// We need to validate the correctness of these slice claims by asserting their sum equals `a`,
// and we also need to validate the bit range of each slice
// (we get an implicit range constraint for free by indexing our BASE4_ENCODE_TABLE lookup tables)
let s = unsafe { decompose_e(e) };

let mut reconstructed = s[8];
reconstructed *= 256;
reconstructed += s[7];
reconstructed *= 128;
reconstructed += s[6];
reconstructed *= 512;
reconstructed += s[5];
reconstructed *= 256;
reconstructed += s[4];
reconstructed *= 64;
reconstructed += s[3];
reconstructed *= 16;
reconstructed += s[2];
reconstructed *= 64;
reconstructed += s[1];
reconstructed *= 256;
reconstructed += s[0];
assert_eq(reconstructed, e); // 7 gates?

// 8, 6, 4, 6, 8, 9, 7, 8, 8

Expand Down Expand Up @@ -493,7 +449,33 @@ pub(crate) fn encode_e(e: Field) -> EncodedChoose {
}

pub(crate) fn encode_a(a: Field) -> EncodedMajority {
let s = decompose_a(a);
//Safety: split input into slices with the following bit sizes:
// 8,8,8,4,6,5,9,8,8
// We need to validate the correctness of these slice claims by asserting their sum equals `a`,
// and we also need to validate the bit range of each slice
// (we get an implicit range constraint for free by indexing our BASE4_ENCODE_TABLE lookup tables)
let s = unsafe { decompose_a(a) };

// 8,8,8,4,6,5,9,8,8
// 7 gates?
let mut reconstructed = s[8];
reconstructed *= 256;
reconstructed += s[7];
reconstructed *= 512;
reconstructed += s[6];
reconstructed *= 32;
reconstructed += s[5];
reconstructed *= 64;
reconstructed += s[4];
reconstructed *= 16;
reconstructed += s[3];
reconstructed *= 256;
reconstructed += s[2];
reconstructed *= 256;
reconstructed += s[1];
reconstructed *= 256;
reconstructed += s[0];
assert_eq(reconstructed, a);

let mut base4_encoded_slices: [Field; 9] = [0; 9];
// 18 gates?
Expand Down

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