CoreLib Functions

Cryptographic Primitives

The Ola team is progressively adding new cryptographic primitives to the standard library. Reach out for news or if you would be interested in adding more of these calculations in Ola.

poseidon_hash

Given an fields (array of fields) or string , returns the resulting poseidon hash.

fn poseidon_hash(fields input) -> (hash)

example:

 string a = "helloworld";
 hash h1 = poseidon_hash(a);

signature

Get the signature of this transaction.

  fn signautre_test() -> (fields) {
      return signature();
  }

check_ecdsa

Verifier for ECDSA Secp256k1 signatures

fn check_ecdsa(hash message, fields pk, fields sig)

example:

fn check_ecdsa_test() {
    hash message = 0x706955c537687b11177b1058f987ecea245a2c0e5d6c0d1ccd3e91db7cbab73ehash;
    fields pubkey = 0xdf31ce59e3db2b1afcfe2618e0bc5907476f6d22971d7cc462da578f3496c623fbd51392f2773b44c5ffcc80acf9b98ae9d809e36d8963eda4765bb77fa716a3fields;
    fields sig = 0x2b87c212f85fc86ec0005cceb9927585e71c3644bb431989713d403cd23800a77cf405c7941c0d53dcb5ae30de730f39759a7fb0f9d7adcfc480f3d3467e31c2fields;
    bool result = check_ecdsa(message, pubkey, sig);
    assert(result);
}

Logging

The standard library provides two familiar statements you can use: println and print. Despite being a limited implementation of rust's print function , these constructs can be useful for debugging.

example:

contract MultInputExample {

    struct Transaction {
        address sender;
        u32 nonce;
        u32 version;
        u32 chainid;
        fields data; 
        fields codes; 
        fields signature;
        hash codeHash; 
    }
    fn foo(Transaction t)  {  
        print(t.sender);
        print(t.nonce);
        print(t.version);
        print(t.chainid);
        print(t.data);
        print(t.codes);
        print(t.signature);
        print(t.codeHash);

    }

}

Assert

ola provides an assertion function, which can ensure the correct execution of some statements. When the assert fails, the transaction will revert.

example:

  fn test() {
      u32[] a = new u32[](5);
      u32 b = a.length;
      assert(b == 5);
  }

BlockChain Context

Ola provides many functions to obtain the status of L2 blockchain. The implementation meaning of these functions is mostly consistent with Solidity, but there are differences in writing.

function name	Params	Returns	Usage
caller_address		contract caller address	address caller = caller_address()
origin_address		contract origin caller address	address origin = origin_address()
code_address		current execute code contract address	address code_addr = code_address()
current_address		current state write and read contract address	address state_addr = current_address()
chain_id		(u32) The future may be replaced by u256 data types.	u32 chainID = chain_id();
block_number		u32	u32 blocknumber = block_number()
block_timestamp		u32	u32 time = block_timestamp()
sequence_address		address	address sequencer = sequence_address()
tx_version		u32	u32 version = tx_version()
nonce		u32	u32 nonce_number = nonce();
tx_hash		hash	hash h = tx_hash()

Utils

Ola provides some utility functions, here is the list of available functions.

function name	Params	Returns	Usage
u32_array_sort	u32 array	sorted array	u32_array_sort([2, 1, 3, 4]);
get_selector		u32	u32 selector = get_selector("setVars(u32)");
fields_concat	fields a and fields b	new fields	fields ret = fields_concat(a, b);
string_concat	string a and string b	new string	string ret = string_concat(a, b);
abi.encode	various types of uncertain quantities	fields	fields encode_value = abi.encode(a, b);
abi.decode	fields data wtih various types	tuple with all type value	u32 result = abi.decode(data, (u32));
abi.encodeWithSignature	string function selector and params	fields	fields call_data = abi.encodeWithSignature("add(u32,u32)", a, b);