mod.rs

use crate::{
    math::field,
    processor::{ OpCode, OpHint },
    utils::{ as_bytes },
    SPONGE_WIDTH, PROGRAM_DIGEST_SIZE, BASE_CYCLE_LENGTH, HACC_NUM_ROUNDS,
};

pub mod assembly;

pub mod blocks;
use blocks::{ ProgramBlock, Span, Group, Switch, Loop };

mod inputs;
pub use inputs::{ ProgramInputs };

mod hashing;
use hashing::{ hash_op, hash_acc, hash_seq };

#[cfg(test)]
mod tests;

// TYPES AND INTERFACES
// ================================================================================================
#[derive(Clone)]
pub struct Program {
    root    : Group,
    hash    : [u8; 32],
}

// PROGRAM IMPLEMENTATION
// ================================================================================================
impl Program {

    /// Constructs a new program from the specified root block.
    pub fn new(root: Group) -> Program {
        
        // make sure the root block starts with BEGIN operation
        match &root.body()[0] {
            ProgramBlock::Span(block) => {
                let (op_code, _) = block.get_op(0);
                assert!(op_code == OpCode::Begin, "a program must start with BEGIN operation");
            },
            _ => panic!("a program must start with a Span block")
        }

        // compute program hash
        let (v0, v1) = root.get_hash();
        let hash = hash_acc(field::ZERO, v0, v1);
        let mut hash_bytes = [0u8; 32];
        hash_bytes.copy_from_slice(as_bytes(&hash[..PROGRAM_DIGEST_SIZE]));

        return Program { root, hash: hash_bytes };
    }
    /// Returns the root block of the program.
    pub fn root(&self) -> &Group {
        return &self.root;
    }

    /// Returns hash of the program.
    pub fn hash(&self) -> &[u8; 32] {
        return &self.hash;
    }
}

impl std::fmt::Debug for Program {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
    {
        let mut body_code = format!("{:?}", self.root);
        // get rid of extra `begin` token
        body_code.replace_range(..6, "");
        write!(f, "{}", body_code)?;

        return Ok(());
    }
}