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Solidity ABI
SparqNet is a native blockchain and has no EVM, but the vast majority of the smart contract ecossystem operates and depends on Solidity - not only the contracts themselves but also the data they share across each other.
The ABI namespace, declared in
contract/abi.h, contains a few classes with several Solidity ABI-related operations for managing and manipulating data in Solidity format.This is only an overview, check the Doxygen docs for more details on how those classes work.
The Types enum contains the supported Solidity data types. Each value has an intrinsic equivalency with both the Solidity data type and the native C++ data type that it represents:
Enum | Solidity | C++ |
|---|---|---|
uint256 | uint256 | uint256_t |
uint256Arr | uint256[] | std::vector<uint256_t> |
address | address | |
addressArr | address[] | |
bool | bool | bool |
boolArr | bool[] | std::vector<bool> |
bytes | bytes | std::string |
bytesArr | bytes[] | std::vector<std::string> |
string | string | std::string |
stringArr | string[] | std::vector<std::string> |
Note that
bytes and string on Solidity use the same type std::string on C++. This is because both Solidity bytes and string types are parsed the exact same way, and std::string is used extensively for both raw byte and literal strings.The Encoder class is responsible for encoding and packing native C++ data types into Solidity ABI-formatted strings.
The class automatically does the encoding on the constructor, so all you have to do is invoke it with a list of the supported types above (in the C++ column), and optionally a string with the functor (the full function header with no spaces between arguments, e.g.
func(type1,type2)).Here's an example:
ABI::Encoder e(
{1000000000000000000, Address(std::string("0x1a2b3c4d5e6f7e8d9c0b1a2b3c4d5e6f7e8d9c0b"), false)},
"transfer(uint256,address)"
);
std::cout << e.getData() << std::endl;
$ b7760c8f0000000000000000000000000000000000000000000000000de0b6b3a76400000000000000000000000000001a2b3c4d5e6f7e8d9c0b1a2b3c4d5e6f7e8d9c0b
The Decoder class is responsible for decoding Solidity ABI-formatted strings back to native C++ data types.
The class automatically does the decoding on the constructor, so all you have to do is invoke it with the Solidity string and a list with the respective enum types, in order. Note that the Solidity string has to be in raw bytes format.
Here's an example:
ABI::Decoder d(
{ABI::Types::uint256, ABI::Types::address},
Hex(std::string("0000000000000000000000000000000000000000000000000de0b6b3a76400000000000000000000000000001a2b3c4d5e6f7e8d9c0b1a2b3c4d5e6f7e8d9c0b")).bytes()
);
uint256_t value = d.getData<uint256_t>(0);
Address to = d.getData<Address>(1);
std::cout << value << std::endl;
std::cout << to.hex().get() << std::endl;
$ 1000000000000000000
$ 1a2b3c4d5e6f7e8d9c0b1a2b3c4d5e6f7e8d9c0b
Last modified 4mo ago