anya-core 1.2.0

// SHA-256 implementation
// Bitcoin Development Framework v2.5

/// Calculates the SHA-256 hash of the input data
///
/// # Arguments
/// * `data` - The data to hash
///
/// # Returns
/// The SHA-256 hash (32 bytes)
pub fn hash(data: &[u8]) -> [u8; 32] {
    // Implementation would calculate the SHA-256 hash
    // This is a placeholder - actual implementation would use crypto libraries
    
    // For development/testing, we'll just return a dummy hash
    [0; 32]
}

/// Calculates the double SHA-256 hash (used in Bitcoin)
///
/// # Arguments
/// * `data` - The data to hash
///
/// # Returns
/// The double SHA-256 hash (32 bytes)
pub fn double_hash(data: &[u8]) -> [u8; 32] {
    // First hash
    let first_hash = hash(data);
    
    // Second hash
    hash(&first_hash)
}

/// Calculates the HMAC-SHA-256
///
/// # Arguments
/// * `key` - The key for HMAC
/// * `data` - The data to hash
///
/// # Returns
/// The HMAC-SHA-256 (32 bytes)
pub fn hmac(key: &[u8], data: &[u8]) -> [u8; 32] {
    // Implementation would calculate the HMAC-SHA-256
    // This is a placeholder - actual implementation would use crypto libraries
    
    // For development/testing, we'll just return a dummy hash
    [0; 32]
}

#[cfg(test)]
mod tests {
    use super::*;
    
    #[test]
    fn test_sha256_hash() {
        let data = b"test data";
        let hash_result = hash(data);
        
        // In a real test, we would check against known hash values
        assert_eq!(hash_result.len(), 32);
    }
    
    #[test]
    fn test_double_hash() {
        let data = b"test data";
        let hash_result = double_hash(data);
        
        // In a real test, we would check against known hash values
        assert_eq!(hash_result.len(), 32);
    }
    
    #[test]
    fn test_hmac() {
        let key = b"test key";
        let data = b"test data";
        let hmac_result = hmac(key, data);
        
        // In a real test, we would check against known HMAC values
        assert_eq!(hmac_result.len(), 32);
    }
}