Bank

An ERC20 interface to native Ontomir SDK tokens for balance queries and supply information

Overview

The Bank precompile provides ERC20-style access to native Ontomir SDK tokens, enabling smart contracts to query balances and token supplies through standardized interfaces. It serves as a Solidity wrapper around the Ontomir SDK x/bank module.

Address: 0x0000000000000000000000000000000000000804

Gas Costs

• balances: 2,851 + (2,851 × (n-1)) where n = number of tokens returned

• totalSupply: 2,477 + (2,477 × (n-1)) where n = number of tokens returned

• supplyOf: 2,477

Primary Methods

balances

Signature: balances(address account) → Balance[] memory

Description: Queries all native token balances for a specific account address and returns an array of Balance (ERC-20 contract address & amount) structures.

```solidity Solidity expandable lines // SPDX-License-Identifier: MIT pragma solidity ^0.8.0;

contract BankExample { address constant BANK_PRECOMPILE = 0x0000000000000000000000000000000000000804; struct Balance { address contractAddress; uint256 amount; } function getAccountBalances(address account) external view returns (Balance[] memory balances) { (bool success, bytes memory result) = BANK_PRECOMPILE.staticcall( abi.encodeWithSignature("balances(address)", account) ); require(success, "Balance query failed"); balances = abi.decode(result, (Balance[])); return balances; } // Convenience function to get caller's balances function getMyBalances() external view returns (Balance[] memory balances) { return this.getAccountBalances(msg.sender); }

}

```javascript Ethers.js expandable lines
import { ethers } from "ethers";

// Connect to the network
const provider = new ethers.JsonRpcProvider("<RPC_URL>");

// Precompile address and ABI
const precompileAddress = "0x0000000000000000000000000000000000000804";
const precompileAbi = [
  "function balances(address account) view returns (tuple(address contractAddress, uint256 amount)[])"
];

// Create a contract instance
const contract = new ethers.Contract(precompileAddress, precompileAbi, provider);

// Address to query
const accountAddress = "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"; // Placeholder

async function getBalances() {
  try {
    const balances = await contract.balances(accountAddress);
    console.log("Balances:", balances);
  } catch (error) {
    console.error("Error fetching balances:", error);
  }
}

getBalances();

# Replace <RPC_URL> and the account address with your actual data.
# Data is ABI-encoded: function selector + padded address
curl -X POST --data '{
    "jsonrpc": "2.0",
    "method": "eth_call",
    "params": [
        {
            "to": "0x0000000000000000000000000000000000000804",
            "data": "0x27e235e3000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045"
        },
        "latest"
    ],
    "id": 1
}' -H "Content-Type: application/json" <RPC_URL>

Parameters:

• account (address): The account address to query balances for

Returns: Array of Balance structures with contractAddress and amount fields

totalSupply

Signature: totalSupply() → Balance[] memory

Description: Queries the total supply of all native tokens in the system. Returns comprehensive supply information for every token registered in the system.

```solidity Solidity expandable lines // SPDX-License-Identifier: MIT pragma solidity ^0.8.0;

contract BankExample { address constant BANK_PRECOMPILE = 0x0000000000000000000000000000000000000804; struct Balance { address contractAddress; uint256 amount; } function getTotalSupply() external view returns (Balance[] memory totalSupply) { (bool success, bytes memory result) = BANK_PRECOMPILE.staticcall( abi.encodeWithSignature("totalSupply()") ); require(success, "Total supply query failed"); totalSupply = abi.decode(result, (Balance[])); return totalSupply; }

}

```javascript Ethers.js expandable lines
import { ethers } from "ethers";

// Connect to the network
const provider = new ethers.JsonRpcProvider("<RPC_URL>");

// Precompile address and ABI
const precompileAddress = "0x0000000000000000000000000000000000000804";
const precompileAbi = [
  "function totalSupply() view returns (tuple(address contractAddress, uint256 amount)[])"
];

// Create a contract instance
const contract = new ethers.Contract(precompileAddress, precompileAbi, provider);

async function getTotalSupply() {
  try {
    const supply = await contract.totalSupply();
    console.log("Total Supply:", supply);
  } catch (error) {
    console.error("Error fetching total supply:", error);
  }
}

getTotalSupply();

# Replace <RPC_URL> with your actual RPC endpoint.
# Data is the function selector for totalSupply()
curl -X POST --data '{
    "jsonrpc": "2.0",
    "method": "eth_call",
    "params": [
        {
            "to": "0x0000000000000000000000000000000000000804",
            "data": "0x18160ddd"
        },
        "latest"
    ],
    "id": 1
}' -H "Content-Type: application/json" <RPC_URL>

Parameters: None

Returns: Array of Balance structures showing total supply for each token

supplyOf

Signature: supplyOf(address erc20Address) → uint256

Description: Queries the total supply of a specific token by providing its ERC20 contract address. More efficient when you need supply information for a single token.

```solidity Solidity expandable lines // SPDX-License-Identifier: MIT pragma solidity ^0.8.0;

contract BankExample { address constant BANK_PRECOMPILE = 0x0000000000000000000000000000000000000804; function getTokenSupply(address erc20Address) external view returns (uint256 supply) { (bool success, bytes memory result) = BANK_PRECOMPILE.staticcall( abi.encodeWithSignature("supplyOf(address)", erc20Address) ); require(success, "Token supply query failed"); supply = abi.decode(result, (uint256)); return supply; } // Helper function to check if token exists (has supply > 0) function tokenExists(address erc20Address) external view returns (bool) { uint256 supply = this.getTokenSupply(erc20Address); return supply > 0; }

}

```javascript Ethers.js expandable lines
import { ethers } from "ethers";

// Connect to the network
const provider = new ethers.JsonRpcProvider("<RPC_URL>");

// Precompile address and ABI
const precompileAddress = "0x0000000000000000000000000000000000000804";
const precompileAbi = [
  "function supplyOf(address erc20Address) view returns (uint256)"
];

// Create a contract instance
const contract = new ethers.Contract(precompileAddress, precompileAbi, provider);

// ERC20 address to query
const erc20Address = "0xdAC17F958D2ee523a2206206994597C13D831ec7"; // Placeholder for a token contract

async function getSupplyOf() {
  try {
    const supply = await contract.supplyOf(erc20Address);
    console.log("Supply of", erc20Address, ":", supply.toString());
  } catch (error) {
    console.error("Error fetching supply:", error);
  }
}

getSupplyOf();

# Replace <RPC_URL> and the token address with your actual data.
# Data is ABI-encoded: function selector + padded address
curl -X POST --data '{
    "jsonrpc": "2.0",
    "method": "eth_call",
    "params": [
        {
            "to": "0x0000000000000000000000000000000000000804",
            "data": "0x62400e4c000000000000000000000000dac17f958d2ee523a2206206994597c13d831ec7"
        },
        "latest"
    ],
    "id": 1
}' -H "Content-Type: application/json" <RPC_URL>

Parameters:

• erc20Address (address): The ERC20 contract address of the token

Returns: Total supply of the specified token as uint256

Data Structures ->

Balance

The Balance struct represents a token balance with its associated ERC20 contract address:

• contractAddress (address): The ERC20 contract address representing the native token

• amount (uint256): Token amount in the smallest denomination

Full Interface & ABI

// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity >=0.8.18;

/// @dev The IBank contract's address.
address constant IBANK_PRECOMPILE_ADDRESS = 0x0000000000000000000000000000000000000804;

/// @dev The IBank contract's instance.
IBank constant IBANK_CONTRACT = IBank(IBANK_PRECOMPILE_ADDRESS);

/// @dev Balance specifies the ERC20 contract address and the amount of tokens.
struct Balance {
    /// contractAddress defines the ERC20 contract address.
    address contractAddress;
    /// amount of tokens
    uint256 amount;
}

/**
 * @author Evmos Team
 * @title Bank Interface
 * @dev Interface for querying balances and supply from the Bank module.
 */
interface IBank {
    /// @dev balances defines a method for retrieving all the native token balances
    /// for a given account.
    /// @param account the address of the account to query balances for.
    /// @return balances the array of native token balances.
    function balances(
        address account
    ) external view returns (Balance[] memory balances);

    /// @dev totalSupply defines a method for retrieving the total supply of all
    /// native tokens.
    /// @return totalSupply the supply as an array of native token balances
    function totalSupply() external view returns (Balance[] memory totalSupply);

    /// @dev supplyOf defines a method for retrieving the total supply of a particular native coin.
    /// @return totalSupply the supply as a uint256
    function supplyOf(
        address erc20Address
    ) external view returns (uint256 totalSupply);
}

{
  "_format": "hh-sol-artifact-1",
  "contractName": "IBank",
  "sourceName": "solidity/precompiles/bank/IBank.sol",
  "abi": [
    {
      "inputs": [
        {
          "internalType": "address",
          "name": "account",
          "type": "address"
        }
      ],
      "name": "balances",
      "outputs": [
        {
          "components": [
            {
              "internalType": "address",
              "name": "contractAddress",
              "type": "address"
            },
            {
              "internalType": "uint256",
              "name": "amount",
              "type": "uint256"
            }
          ],
          "internalType": "struct Balance[]",
          "name": "balances",
          "type": "tuple[]"
        }
      ],
      "stateMutability": "view",
      "type": "function"
    },
    {
      "inputs": [
        {
          "internalType": "address",
          "name": "erc20Address",
          "type": "address"
        }
      ],
      "name": "supplyOf",
      "outputs": [
        {
          "internalType": "uint256",
          "name": "totalSupply",
          "type": "uint256"
        }
      ],
      "stateMutability": "view",
      "type": "function"
    },
    {
      "inputs": [],
      "name": "totalSupply",
      "outputs": [
        {
          "components": [
            {
              "internalType": "address",
              "name": "contractAddress",
              "type": "address"
            },
            {
              "internalType": "uint256",
              "name": "amount",
              "type": "uint256"
            }
          ],
          "internalType": "struct Balance[]",
          "name": "totalSupply",
          "type": "tuple[]"
        }
      ],
      "stateMutability": "view",
      "type": "function"
    }
  ],
  "bytecode": "0x",
  "deployedBytecode": "0x",
  "linkReferences": {},
  "deployedLinkReferences": {}
}

Implementation Details

Token Resolution

The precompile resolves native Ontomir SDK denominations to their corresponding ERC-20 contract addresses through the x/erc20 module's token pair registry. Only tokens with registered token pairs are returned in query results.

Decimal Precision

All amounts returned preserve the original decimal precision stored in the x/bank module. No decimal conversion is performed by the precompile.

Gas Metering

The precompile implements efficient gas metering by:

• Charging base gas for the first result

• Incrementally charging for each additional result in batch queries

• Consuming gas before returning results to prevent DoS vectors

Error Handling

• Invalid token addresses in supplyOf return 0 rather than reverting

• Queries for accounts with no balances return empty arrays

• All methods are read-only and cannot modify state