solidity/test/libsolidity/semanticTests/abiDecodeV1/dynamic_memory_copy.sol

27 lines
1.5 KiB
Solidity
Raw Normal View History

contract C {
function test(bytes memory buf) public view returns (bool same, bool inplaceDecoded) {
(uint256[] memory arr1, uint256[] memory arr2) = abi.decode(buf, (uint256[],uint256[]));
assembly {
// Check whether arr1 and arr2 end up at the same memory location.
// This used to be the case, if both tail pointers in buf pointed to the
// same memory region, i.e. this used to be false in the first two, but true
// in the last three calls below. The desired behaviour is to always get distinct
// memory regions, i.e. this should be false.
same := eq(arr1, arr2)
// Check whether (given the particular tail pointer of 0x40 for arr1 in the calls below)
// arr1 points to the part of buf containing the encoding of arr1.
// The position of the encoding of arr1 in buf is at offset 0x20 (length) + 0x40 (tail pointer)
// of buf.
// This used to be the case for all the test calls below, whereas now arr1 is always copied
// from buf to a new memory area. Should always be false.
inplaceDecoded := eq(arr1, add(buf, 0x60))
}
}
}
// ----
// test(bytes): 0x20, 0x80, 0x40, 0x60, 0, 0 -> false, false
// test(bytes): 0x20, 0xC0, 0x40, 0x80, 1, 0x42, 1, 0x42 -> false, false
// test(bytes): 0x20, 0x80, 0x40, 0x40, 1, 0x42 -> false, false
// test(bytes): 0x20, 0x60, 0x40, 0x40, 0 -> false, false
// test(bytes): 0x20, 0x80, 0x40, 0x40, 1, 0x42 -> false, false