flashloan-rs 0.2.0

Minimal Multicall3 Flashloan Module
Documentation 
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/// @title ERC-20 Helper
/// @notice SPDX-License-Identifier: MIT
/// @author Ben Leimberger <https://github.com/benleim>
/// @notice Util macros for ERC-20 interactions

// Interface
#define function transfer(address,uint256) nonpayable returns (bool)

/// @notice Transfers an ERC-20 token from the caller to the given account
#define macro ERC20_TRANSFER() = takes (3) returns (0) {
    // input stack:                [acct_addr, amount, getter_addr]
    __FUNC_SIG(transfer)        // [sig, acct_addr, amount, getter_addr]
    0x00 mstore                 // [acct_addr, amount, getter_addr]

    // store args in memory
    // address, uint256
    dup1 0x20 mstore            // [acct_addr, amount, getter_addr]
    dup2 0x40 mstore            // [acct_addr, amount, getter_addr]

    // make call. return size is zero because we can fetch it after the call
    0x00                        // [ret_size, acct_addr, amount, getter_addr]
    dup1                        // [ret_offset, ret_size, acct_addr, amount, getter_addr]
    0x44                        // [args_size, ret_offset, ret_size, acct_addr, amount, getter_addr]
    0x1c                        // [args_offset, args_size, ret_offset, ret_size, acct_addr, amount, getter_addr]
    dup3                        // [value, args_offset, args_size, ret_offset, ret_size, acct_addr, amount, getter_addr]
    dup8                        // [to, value, args_offset, args_size, ret_offset, ret_size, acct_addr, amount, getter_addr]
    gas                         // [gas, to, value, args_offset, args_size, ret_offset, ret_size, acct_addr, amount, getter_addr]
    call                        // [successs, acct_addr, amount, getter_addr]

    iszero iszero               // [success, acct_addr, amount, getter_addr]
    transfer_success jumpi      // [acct_addr, amount, getter_addr]
    0x00 dup1 revert            // [] - Call failed, revert

    // Resume execution in invoking macro
    transfer_success:
}

/// @notice Helper to copy return data into memory
#define macro COPY_RETURN_DATA(mem_offset, dest_offset) = takes (0) returns (0) {
    returndatasize          // [returndatasize]
    <mem_offset>            // [mem_offset, returndatasize]
    <dest_offset>           // [destOffset, mem_offset, returndatasize]
    returndatacopy          // [] - This stores the return data in memory
}

/// @notice Helper to return data with unknown size from memory
#define macro RETURN_DATA(mem_offset) = takes (0) returns (0) {
    returndatasize          // [returndatasize]
    <mem_offset>            // [mem_offset, returndatasize]
    return                  // []
}