revm_precompile/bls12_381/
utils.rs

1//! BLS12-381 utilities for padding and unpadding of input.
2use crate::bls12_381_const::{
3    FP_LENGTH, FP_PAD_BY, PADDED_FP_LENGTH, PADDED_G1_LENGTH, PADDED_G2_LENGTH,
4};
5use crate::PrecompileError;
6
7/// Removes zeros with which the precompile inputs are left padded to 64 bytes.
8pub(super) fn remove_fp_padding(input: &[u8]) -> Result<&[u8; FP_LENGTH], PrecompileError> {
9    if input.len() != PADDED_FP_LENGTH {
10        return Err(PrecompileError::Other(format!(
11            "Padded input should be {PADDED_FP_LENGTH} bytes, was {}",
12            input.len()
13        )));
14    }
15    let (padding, unpadded) = input.split_at(FP_PAD_BY);
16    if !padding.iter().all(|&x| x == 0) {
17        return Err(PrecompileError::Other(format!(
18            "{FP_PAD_BY} top bytes of input are not zero",
19        )));
20    }
21    Ok(unpadded.try_into().unwrap())
22}
23/// remove_g1_padding removes the padding applied to the Fp elements that constitute the
24/// encoded G1 element.
25pub(super) fn remove_g1_padding(input: &[u8]) -> Result<[&[u8; FP_LENGTH]; 2], PrecompileError> {
26    if input.len() != PADDED_G1_LENGTH {
27        return Err(PrecompileError::Other(format!(
28            "Input should be {PADDED_G1_LENGTH} bytes, was {}",
29            input.len()
30        )));
31    }
32
33    let x = remove_fp_padding(&input[..PADDED_FP_LENGTH])?;
34    let y = remove_fp_padding(&input[PADDED_FP_LENGTH..PADDED_G1_LENGTH])?;
35    Ok([x, y])
36}
37
38/// remove_g2_padding removes the padding applied to the Fp elements that constitute the
39/// encoded G2 element.
40pub(super) fn remove_g2_padding(input: &[u8]) -> Result<[&[u8; FP_LENGTH]; 4], PrecompileError> {
41    if input.len() != PADDED_G2_LENGTH {
42        return Err(PrecompileError::Other(format!(
43            "Input should be {PADDED_G2_LENGTH} bytes, was {}",
44            input.len()
45        )));
46    }
47
48    let mut input_fps = [&[0; FP_LENGTH]; 4];
49    for i in 0..4 {
50        input_fps[i] = remove_fp_padding(&input[i * PADDED_FP_LENGTH..(i + 1) * PADDED_FP_LENGTH])?;
51    }
52    Ok(input_fps)
53}
revm_precompile/bls12_381/utils.rs

revm_precompile/bls12_381/
utils.rs
