flashloan-rs 0.2.3

Minimal Multicall3 Flashloan Module
Documentation 
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/// @title JumpTableUtil
/// @notice SPDX-License-Identifier: MIT
/// @author clabby <https://github.com/clabby>
/// @notice Utility macros for retrieving jumpdest pcs from jump tables

/// @notice Loads a jumpdest stored in a jumptable into memory at `mem_ptr`
///
/// @param mem_ptr The memory location to load the 2 byte jumpdest into
/// @param index The index of the jumpdest within the jumptable
/// @param table_start The offset of the jumptable in the contract's bytecode
#define macro LOAD_FROM_JT(mem_ptr) = takes (2) returns (1) {
    // Input stack:       [index, table_start]

    0x20 mul add       // [table_start + index * 0x20]
    0x20 swap1         // [table_start + index * 0x20, 0x20]
    <mem_ptr>          // [mem_ptr, table_start + index * 0x20, 0x20]
    codecopy           // []

    // Return stack:      []
}

/// @notice Retrieves a jumpdest stored in a jumptable and puts it on the stack
///
/// @param index The index of the jumpdest within the jumptable
/// @param table_start The offset of the jumptable in the contract's bytecode
#define macro RETRIEVE_FROM_JT() = takes (2) returns (1) {
    // Input stack:       [index, table_start]

    LOAD_FROM_JT(0x00) // []
    0x00 mload         // [res]

    // Return stack:      [res]
}

/// @notice Loads a jumpdest stored in a packed jumptable into memory at `mem_ptr`
/// @dev This macro only loads 2 bytes from the contract code, so make sure to account
///      for this when passing a `mem_ptr`. I.e., if we want to store the jumpdest pc
///      at offset `x`, we would pass in `x + 0x1e` as the `mem_ptr` argument.
///
/// @param mem_ptr The memory location to load the 2 byte jumpdest into
/// @param index The index of the jumpdest within the packed jumptable
/// @param table_start The offset of the packed jumptable in the contract's bytecode
#define macro LOAD_FROM_PACKED_JT(mem_ptr) = takes (2) returns (1) {
    // Input stack:       [index, table_start]

    0x02 mul add       // [table_start + index * 0x02]
    0x02 swap1         // [table_start + index * 0x02, 0x02]
    <mem_ptr>          // [mem_ptr, table_start + index * 0x02, 0x02]
    codecopy           // []

    // Return stack:      []
}

/// @notice Retrieves a jumpdest stored in a packed jumptable and puts it on the stack
///
/// @param index The index of the jumpdest within the packed jumptable
/// @param table_start The offset of the packed jumptable in the contract's bytecode
#define macro RETRIEVE_FROM_PACKED_JT() = takes (2) returns (1) {
    // Input stack:       [index, table_start]

    LOAD_FROM_PACKED_JT(0x1e)
    //                    []
    0x00 mload         // [res]

    // Return stack:      [res]
}