simplicity-lang 0.7.0

// SPDX-License-Identifier: CC0-1.0

use crate::impl_midstate_wrapper;
use hashes::sha256::Midstate;

/// Type Merkle root
///
/// A Merkle root that commits to a type's primitive (unit, sum, product)
/// and recursively its sub-types.
///
/// Uniquely identifies a type.
#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct Tmr(pub(crate) Midstate);

impl_midstate_wrapper!(Tmr);

impl Tmr {
    #[rustfmt::skip]
    const UNIT_IV: Tmr = Tmr(Midstate([
        0x50, 0xb3, 0x8c, 0xd7, 0x64, 0x75, 0xff, 0x89,
        0x29, 0x28, 0x8b, 0xfc, 0xd0, 0xd9, 0xdf, 0x0e,
        0x4a, 0x24, 0x1c, 0x0a, 0x57, 0x08, 0x57, 0x2a,
        0xd2, 0x64, 0x19, 0x2a, 0x4f, 0xe6, 0x7b, 0xee,
    ]));

    #[rustfmt::skip]
    const SUM_IV: Tmr = Tmr(Midstate([
        0x92, 0x0c, 0xfd, 0x83, 0xcf, 0x96, 0xbb, 0x32,
        0x73, 0x17, 0x36, 0x0f, 0x6d, 0x3a, 0xd7, 0x60,
        0x1e, 0xef, 0x0a, 0x16, 0xdd, 0x53, 0x14, 0x6c,
        0x2e, 0x5d, 0xe3, 0x5f, 0x51, 0xef, 0x8d, 0xa4,
    ]));

    #[rustfmt::skip]
    const PROD_IV: Tmr = Tmr(Midstate([
        0xae, 0x99, 0x2a, 0x3e, 0xe0, 0x71, 0x3b, 0xf6,
        0x19, 0x5d, 0x3b, 0xac, 0x1a, 0xf5, 0x05, 0xa7,
        0x29, 0xc1, 0x4d, 0x47, 0x95, 0x58, 0xf0, 0xd6,
        0x29, 0x96, 0x30, 0xf7, 0xfa, 0x97, 0x2e, 0xf8,
    ]));

    /// The TMRs of the types TWO^(2^n) for small values of n
    #[rustfmt::skip]
    pub const TWO_TWO_N: [Tmr; 32] = [
        Tmr(Midstate([
            0x88, 0x5a, 0x22, 0xde, 0x3e, 0xdb, 0x3f, 0x40,
            0xdb, 0x06, 0x09, 0xc2, 0x40, 0x23, 0x30, 0x3f,
            0xec, 0x67, 0x87, 0xbe, 0x4d, 0x49, 0x21, 0xe4,
            0x5e, 0xe9, 0xd9, 0x83, 0xac, 0xb5, 0xd8, 0x9d,
        ])),
        Tmr(Midstate([
            0x55, 0x22, 0xba, 0x1c, 0x92, 0x89, 0x4d, 0xf2,
            0x57, 0x23, 0xcf, 0xeb, 0x5a, 0xf2, 0x59, 0xf4,
            0xc5, 0x5a, 0x5c, 0xfc, 0x82, 0x00, 0xd5, 0x9b,
            0xad, 0x09, 0x64, 0x99, 0x7f, 0x9b, 0x2b, 0x04,
        ])),
        Tmr(Midstate([
            0xfa, 0x28, 0xba, 0x9f, 0x0f, 0x07, 0xb4, 0xfa,
            0xe4, 0xdd, 0x86, 0x23, 0x61, 0x41, 0x12, 0xff,
            0x3b, 0xaf, 0xab, 0xe2, 0x9c, 0x41, 0x5d, 0x2e,
            0x0c, 0x1e, 0xd3, 0xc4, 0x13, 0x51, 0x28, 0xe0,
        ])),
        Tmr(Midstate([
            0xd3, 0x43, 0xe4, 0xd5, 0xfa, 0xa4, 0xce, 0xa4,
            0x4b, 0xb7, 0x11, 0xef, 0x4b, 0x1b, 0x96, 0xb7,
            0xe0, 0xfb, 0x26, 0xcf, 0xa8, 0x5a, 0x96, 0x04,
            0x39, 0xba, 0x84, 0x58, 0xc0, 0xb6, 0xc5, 0xc3,
        ])),
        Tmr(Midstate([
            0x62, 0x8c, 0x36, 0x1f, 0x09, 0xcb, 0x2e, 0x5b,
            0xaa, 0xd9, 0xc6, 0xb7, 0x26, 0xa9, 0xfa, 0x95,
            0xd1, 0xda, 0x67, 0x79, 0x7e, 0xe2, 0x4c, 0xcf,
            0x01, 0x41, 0x0c, 0x97, 0x93, 0x39, 0x95, 0x00,
        ])),
        Tmr(Midstate([
            0xb1, 0xa9, 0xf9, 0x68, 0x78, 0x33, 0xdc, 0x44,
            0xbc, 0x8f, 0x17, 0xd3, 0xcb, 0xc2, 0x55, 0xb7,
            0xaa, 0x49, 0x9a, 0x78, 0xfe, 0xc8, 0x5c, 0xc9,
            0x8a, 0x0c, 0x33, 0x5c, 0x86, 0xed, 0x26, 0xe9,
        ])),
        Tmr(Midstate([
            0xfd, 0x75, 0xbc, 0xd8, 0xcb, 0x55, 0xa5, 0xe4,
            0x24, 0xe0, 0x92, 0x88, 0xac, 0x8e, 0xb4, 0x29,
            0x42, 0x53, 0x4e, 0xc1, 0x09, 0x9b, 0x72, 0xbe,
            0xce, 0x0e, 0xa2, 0xc5, 0x47, 0x9b, 0xf3, 0xe7,
        ])),
        Tmr(Midstate([
            0xe3, 0x94, 0xd2, 0xa0, 0x51, 0x6d, 0x73, 0x8d,
            0x6e, 0x04, 0x59, 0xb9, 0x1b, 0xb0, 0xdd, 0x47,
            0x1d, 0x0d, 0xaa, 0x77, 0x96, 0x71, 0xa5, 0x31,
            0x3b, 0x62, 0x14, 0x0e, 0xc7, 0x0a, 0x22, 0x6e,
        ])),
        Tmr(Midstate([
            0xe4, 0xc4, 0x72, 0x8d, 0x87, 0x67, 0x49, 0xbe,
            0xbe, 0x4d, 0x62, 0x97, 0xdf, 0xad, 0xd4, 0x2c,
            0xe2, 0x68, 0x44, 0x50, 0x0d, 0x96, 0xc5, 0xe9,
            0x14, 0x61, 0x57, 0x50, 0x8e, 0xb9, 0x09, 0x8f,
        ])),
        Tmr(Midstate([
            0x1a, 0xe5, 0x45, 0xb7, 0xc3, 0xfd, 0x85, 0xfe,
            0x81, 0x6c, 0x70, 0xea, 0x4c, 0x78, 0xb7, 0x41,
            0x9d, 0x8b, 0xe3, 0xc1, 0xfb, 0x3f, 0x72, 0x23,
            0xfa, 0x7d, 0x8d, 0x50, 0x36, 0x75, 0x51, 0x8f,
        ])),
        Tmr(Midstate([
            0x6a, 0x9c, 0x72, 0x40, 0xe5, 0xd7, 0x1d, 0x5a,
            0x83, 0x30, 0xb3, 0xb3, 0xb6, 0x65, 0x0b, 0xc3,
            0x66, 0x6c, 0x3f, 0xef, 0x2e, 0x80, 0x3e, 0xd8,
            0x64, 0xf1, 0x2f, 0xcd, 0x8f, 0xea, 0xc1, 0xca,
        ])),
        Tmr(Midstate([
            0x0a, 0x2a, 0x58, 0x7a, 0xeb, 0xc9, 0x6b, 0x0e,
            0x3e, 0x26, 0x01, 0x38, 0x2e, 0xb3, 0x2a, 0x9f,
            0x1e, 0x29, 0xc8, 0x50, 0x1c, 0xbd, 0xd8, 0x0e,
            0x87, 0x05, 0xc0, 0xe7, 0xd3, 0xf5, 0xb3, 0x4f,
        ])),
        Tmr(Midstate([
            0xb3, 0xed, 0xb6, 0xfd, 0x83, 0x8e, 0xc4, 0x05,
            0x7b, 0x76, 0x8c, 0x86, 0xb0, 0xe8, 0xa9, 0x6d,
            0x1c, 0xe3, 0xf1, 0x69, 0x54, 0x31, 0x4d, 0xcd,
            0x3d, 0xbf, 0x72, 0x85, 0xeb, 0xa5, 0x63, 0xa9,
        ])),
        Tmr(Midstate([
            0xd0, 0x47, 0x4c, 0x0c, 0x1e, 0x2c, 0x09, 0xd9,
            0xc5, 0xf0, 0x50, 0x98, 0x93, 0x57, 0xce, 0x71,
            0xab, 0x5d, 0x90, 0x4e, 0x8e, 0x2e, 0x82, 0x87,
            0x42, 0x86, 0xc0, 0xc2, 0x12, 0xde, 0x3e, 0x71,
        ])),
        Tmr(Midstate([
            0x37, 0x92, 0x46, 0xdc, 0x86, 0x6d, 0x37, 0x0d,
            0xbf, 0xc9, 0x70, 0x4f, 0xbc, 0x57, 0xcd, 0x7a,
            0x6e, 0xb5, 0xed, 0xe7, 0x97, 0xa0, 0x0c, 0x4a,
            0x72, 0xb3, 0xb4, 0xa5, 0xd9, 0xf0, 0x9f, 0xe1,
        ])),
        Tmr(Midstate([
            0x8a, 0x59, 0xe8, 0x3f, 0x43, 0xe2, 0xa1, 0xf9,
            0x07, 0xd3, 0xa2, 0x96, 0x67, 0x53, 0x33, 0x6a,
            0x1d, 0xa2, 0x0d, 0x23, 0xfe, 0x63, 0x63, 0x28,
            0x58, 0xf9, 0x4e, 0xc0, 0x7d, 0x19, 0x13, 0xd2,
        ])),
        Tmr(Midstate([
            0x0f, 0x51, 0x95, 0x68, 0x9f, 0x55, 0x6d, 0x00,
            0xbe, 0x92, 0xfc, 0x2d, 0xc5, 0x7b, 0xcb, 0xb1,
            0x25, 0x62, 0x0f, 0xfc, 0x00, 0x96, 0x3c, 0x09,
            0x14, 0xb1, 0x96, 0x15, 0x1a, 0x77, 0x84, 0x1c,
        ])),
        Tmr(Midstate([
            0x6d, 0x2a, 0x47, 0x99, 0xa1, 0x6e, 0xb6, 0x78,
            0x4e, 0x49, 0x66, 0xb8, 0x1d, 0xa6, 0x27, 0xd3,
            0x5a, 0xa7, 0x08, 0xfd, 0x97, 0x25, 0xd6, 0x04,
            0x77, 0x7b, 0x14, 0x3e, 0x28, 0xd4, 0xac, 0xf0,
        ])),
        Tmr(Midstate([
            0x2a, 0x07, 0x5c, 0x50, 0xca, 0x10, 0xe5, 0x00,
            0x92, 0x77, 0x86, 0xca, 0x86, 0xa5, 0x2b, 0xb7,
            0xe5, 0x2d, 0xdb, 0x16, 0x42, 0xe3, 0x77, 0x45,
            0xfb, 0x44, 0x14, 0x91, 0x39, 0xb3, 0x2d, 0x67,
        ])),
        Tmr(Midstate([
            0xf5, 0x67, 0xc8, 0x1b, 0x82, 0x5d, 0xc9, 0x00,
            0xe0, 0xbc, 0x0c, 0x59, 0xce, 0xa6, 0xaa, 0x1f,
            0x1f, 0x34, 0x28, 0x3f, 0xcb, 0xee, 0xff, 0x73,
            0x2d, 0xb8, 0xe2, 0x17, 0x57, 0x6c, 0x22, 0x55,
        ])),
        Tmr(Midstate([
            0x0a, 0xee, 0x10, 0x39, 0xd3, 0xc8, 0xaf, 0x91,
            0x41, 0xbc, 0xb9, 0xfd, 0xf3, 0xf8, 0x24, 0x1e,
            0xf9, 0xfd, 0x4b, 0x85, 0x85, 0x3a, 0x79, 0xba,
            0xbc, 0xfb, 0x2a, 0xb4, 0xdb, 0x8e, 0xf3, 0x8c,
        ])),
        Tmr(Midstate([
            0x30, 0xaa, 0xe9, 0xb8, 0xf2, 0xc6, 0xfa, 0xf0,
            0x7a, 0x62, 0x07, 0x2f, 0x55, 0xb2, 0x96, 0x98,
            0x5d, 0xd7, 0x3b, 0xc1, 0x04, 0x42, 0xc8, 0x02,
            0x79, 0x32, 0xff, 0xf4, 0x1f, 0x2a, 0x2d, 0x72,
        ])),
        Tmr(Midstate([
            0xbc, 0x14, 0x6c, 0xb5, 0xae, 0x67, 0xe0, 0x0a,
            0x6d, 0x8e, 0x3f, 0xd0, 0x56, 0xfb, 0x7a, 0x72,
            0x82, 0x04, 0x84, 0xc6, 0x1a, 0xcf, 0x17, 0xfe,
            0xcc, 0xf1, 0x30, 0xcb, 0xa6, 0x22, 0xd2, 0x7f,
        ])),
        Tmr(Midstate([
            0xa8, 0x67, 0xba, 0xcf, 0xf8, 0xd1, 0xc2, 0x5c,
            0x9e, 0x82, 0x4f, 0x1b, 0x63, 0xa4, 0x9c, 0x17,
            0x67, 0x9b, 0xba, 0x8a, 0xd8, 0x76, 0x99, 0xa0,
            0xcd, 0xf7, 0x7d, 0xef, 0x0a, 0x1b, 0x75, 0x11,
        ])),
        Tmr(Midstate([
            0xc1, 0x28, 0xdc, 0x7e, 0x8d, 0x79, 0x4a, 0x7a,
            0x48, 0x08, 0x14, 0x95, 0xa6, 0xeb, 0x2b, 0x2d,
            0x3c, 0xb6, 0x6b, 0xc0, 0xe0, 0x33, 0x27, 0x3b,
            0xf9, 0xdd, 0xbc, 0x98, 0x6c, 0x22, 0x68, 0x92,
        ])),
        Tmr(Midstate([
            0x19, 0x9f, 0xfd, 0xe4, 0x7d, 0x27, 0x91, 0xa3,
            0x58, 0xf2, 0x3a, 0xe5, 0x08, 0x25, 0x16, 0xc6,
            0x5e, 0x57, 0xf5, 0x5a, 0xe6, 0x6d, 0xdf, 0x44,
            0x65, 0xba, 0xab, 0x4b, 0xfa, 0x3c, 0x3a, 0x5f,
        ])),
        Tmr(Midstate([
            0x40, 0x38, 0x09, 0x5d, 0xbb, 0x32, 0xe2, 0x7e,
            0x6e, 0x31, 0x66, 0x52, 0x7b, 0xce, 0xdd, 0xa8,
            0x4e, 0x8b, 0x21, 0xf6, 0xd4, 0x2f, 0x7e, 0x56,
            0xea, 0xff, 0x21, 0x85, 0x6a, 0xd2, 0x04, 0xa2,
        ])),
        Tmr(Midstate([
            0xc3, 0xa0, 0xa6, 0xf8, 0x7e, 0x6c, 0x3f, 0x02,
            0xbf, 0x98, 0x05, 0x1c, 0xe4, 0x5d, 0x6d, 0x69,
            0x55, 0x38, 0x24, 0x78, 0xf1, 0x0f, 0xa0, 0x6a,
            0xdd, 0x51, 0x30, 0xe5, 0x99, 0x17, 0xf8, 0xc7,
        ])),
        Tmr(Midstate([
            0x7c, 0x25, 0xbf, 0x44, 0x7a, 0x45, 0xba, 0x13,
            0x23, 0xe8, 0xdb, 0x8b, 0x81, 0x78, 0x87, 0xa8,
            0x85, 0x8b, 0xee, 0x25, 0x6e, 0x5c, 0xa3, 0x52,
            0x8e, 0x79, 0xcf, 0xbc, 0x2d, 0x41, 0x9c, 0xe3,
        ])),
        Tmr(Midstate([
            0x75, 0xa7, 0x7a, 0x6c, 0x7b, 0x6d, 0xe9, 0x1d,
            0x23, 0xc1, 0x00, 0x4d, 0x8e, 0xb0, 0xb3, 0x5d,
            0x9c, 0xdf, 0x6f, 0xa1, 0xdf, 0xc7, 0xca, 0xbd,
            0x04, 0x66, 0x92, 0xf1, 0xa2, 0x43, 0x14, 0x17,
        ])),
        Tmr(Midstate([
            0x9f, 0xc2, 0x4a, 0xb6, 0x99, 0x70, 0xf8, 0x66,
            0x6d, 0x7b, 0x1e, 0x52, 0x5a, 0x3a, 0x8e, 0x79,
            0x43, 0x99, 0x76, 0xe7, 0x79, 0x2b, 0xfe, 0x1a,
            0x1b, 0x0d, 0x0d, 0x84, 0xff, 0x03, 0x84, 0x34,
        ])),
        Tmr(Midstate([
            0x64, 0x25, 0x1a, 0xb9, 0x70, 0x77, 0x17, 0x0e,
            0x19, 0x91, 0x15, 0x76, 0x5e, 0x93, 0x43, 0xe7,
            0x1b, 0x59, 0x0e, 0x41, 0x78, 0x88, 0xf2, 0xa8,
            0x36, 0x43, 0x11, 0xd8, 0x65, 0x40, 0xed, 0xfa,
        ])),
    ];

    /// The TMR for the unit type
    pub const fn unit() -> Tmr {
        Self::UNIT_IV
    }

    /// The TMR for the sum of two types, whose TMRs are given
    pub fn sum(tmr1: Tmr, tmr2: Tmr) -> Tmr {
        Self::SUM_IV.update(tmr1, tmr2)
    }

    /// The TMR for the product of two types, whose TMRs are given
    pub fn product(tmr1: Tmr, tmr2: Tmr) -> Tmr {
        Self::PROD_IV.update(tmr1, tmr2)
    }
}

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

    use crate::merkle::bip340_iv;
    use crate::types;

    #[test]
    fn ivs() {
        fn check_iv(target: Tmr, s: &'static str) {
            let name = s.trim_start_matches("Simplicity\x1fType\x1f");
            // Uncomment this if the IVs ever change
            /*
            let target = Tmr(bip340_iv(s.as_bytes()));
            println!("    #[rustfmt::skip]");
            println!("    const {}_IV: Tmr = Tmr(Midstate([", name.to_ascii_uppercase());
            print!("       "); for ch in &target.0[0..8] { print!(" 0x{:02x},", ch); }; println!();
            print!("       "); for ch in &target.0[8..16] { print!(" 0x{:02x},", ch); }; println!();
            print!("       "); for ch in &target.0[16..24] { print!(" 0x{:02x},", ch); }; println!();
            print!("       "); for ch in &target.0[24..32] { print!(" 0x{:02x},", ch); }; println!();
            println!("    ]));");
            println!();
            */
            assert_eq!(
                target,
                Tmr(bip340_iv(s.as_bytes())),
                "mismatch on IV for {}",
                name
            );
        }

        check_iv(Tmr::UNIT_IV, "Simplicity\x1fType\x1funit");
        check_iv(Tmr::SUM_IV, "Simplicity\x1fType\x1fsum");
        check_iv(Tmr::PROD_IV, "Simplicity\x1fType\x1fprod");
    }

    #[test]
    #[allow(clippy::needless_range_loop)]
    fn const_powers_of_2() {
        fn check_pow(target: Tmr, i: usize, expected_tmrs: &[Tmr]) {
            // Uncomment this if the IVs ever change
            /*
            let target = tmrs[i];
            println!("    Tmr(Midstate([");
            print!("       "); for ch in &target.0[0..8] { print!(" 0x{:02x},", ch); }; println!();
            print!("       "); for ch in &target.0[8..16] { print!(" 0x{:02x},", ch); }; println!();
            print!("       "); for ch in &target.0[16..24] { print!(" 0x{:02x},", ch); }; println!();
            print!("       "); for ch in &target.0[24..32] { print!(" 0x{:02x},", ch); }; println!();
            println!("    ])),");
            */
            assert_eq!(target, expected_tmrs[i], "mismatch on TMR for TWO^(2^{i})");
        }

        let n = Tmr::TWO_TWO_N.len();
        types::Context::with_context(|ctx| {
            let tmrs = types::Type::powers_of_two(&ctx, n)
                .iter()
                .filter_map(types::Type::tmr)
                .collect::<Vec<Tmr>>();
            debug_assert_eq!(tmrs.len(), n);
            for i in 0..n {
                check_pow(Tmr::TWO_TWO_N[i], i, &tmrs);
            }
        });
    }
}