ziskos-hints 1.1.0-alpha

use crate::{handlers::validate_hint_length, hint_fields, zisklib};

use anyhow::Result;

/// Processes an `HINT_BN254_G1_ADD` hint.
#[inline]
pub fn bn254_g1_add_hint(data: &[u64]) -> Result<Vec<u64>> {
    hint_fields![P1: 64, P2: 64];

    let bytes = unsafe { std::slice::from_raw_parts(data.as_ptr() as *const u8, data.len() * 8) };

    validate_hint_length(bytes, EXPECTED_LEN, "HINT_BN254_G1_ADD")?;

    let p1: &[u8; P1_SIZE] = bytes[P1_OFFSET..P1_OFFSET + P1_SIZE].try_into().unwrap();
    let p2: &[u8; P2_SIZE] = bytes[P2_OFFSET..P2_OFFSET + P2_SIZE].try_into().unwrap();

    let mut hints = Vec::new();
    let result: &mut [u8; 64] = &mut [0u8; 64];
    unsafe {
        zisklib::add_safe_bn254_c(p1.as_ptr(), p2.as_ptr(), result.as_mut_ptr(), &mut hints);
    }

    Ok(hints)
}

/// Processes an `HINT_BN254_G1_MUL` hint.
#[inline]
pub fn bn254_g1_mul_hint(data: &[u64]) -> Result<Vec<u64>> {
    hint_fields![POINT: 64, SCALAR: 32];

    let bytes = unsafe { std::slice::from_raw_parts(data.as_ptr() as *const u8, data.len() * 8) };

    validate_hint_length(bytes, EXPECTED_LEN, "HINT_BN254_G1_MUL")?;

    let point: &[u8; POINT_SIZE] =
        bytes[POINT_OFFSET..POINT_OFFSET + POINT_SIZE].try_into().unwrap();
    let scalar: &[u8; SCALAR_SIZE] =
        bytes[SCALAR_OFFSET..SCALAR_OFFSET + SCALAR_SIZE].try_into().unwrap();

    let mut hints = Vec::new();
    let result: &mut [u8; 64] = &mut [0u8; 64];
    unsafe {
        zisklib::scalar_mul_safe_bn254_c(
            point.as_ptr(),
            scalar.as_ptr(),
            result.as_mut_ptr(),
            &mut hints,
        );
    }

    Ok(hints)
}

/// Processes an `HINT_BN254_PAIRING_CHECK` hint.
#[inline]
pub fn bn254_pairing_check_hint(data: &[u64]) -> Result<Vec<u64>> {
    const G1_WORDS: usize = 8;
    const G2_WORDS: usize = 16;
    const PAIR_WORDS: usize = G1_WORDS + G2_WORDS;

    if data.is_empty() {
        anyhow::bail!("BN254_PAIRING_CHECK: data is empty");
    }

    let num_pairs = data[0] as usize;

    let expected_len = 1 + num_pairs * PAIR_WORDS;

    validate_hint_length(data, expected_len, "PAIRING_BATCH_BN254")?;

    let pairs_data = &data[1..];

    let mut hints = Vec::new();
    unsafe {
        zisklib::pairing_check_safe_bn254_c(
            pairs_data.as_ptr() as *const u8,
            num_pairs,
            &mut hints,
        );
    }

    Ok(hints)
}