Dynamic Length Inputs

• How variable length arguments are encoded in calldata

// Example: dynamic length data type sandwiched between two fixed length data types 
function threeArgs(
        uint256 a,
        uint256[] calldata b,
        uint256 c
    ) external {}

• calldata for input values of 5, [1,2,3], 7

0xc6f922d0
0000000000000000000000000000000000000000000000000000000000000005 // first input argument 
0000000000000000000000000000000000000000000000000000000000000060 // 60 - pointer to location of dynamic array data
0000000000000000000000000000000000000000000000000000000000000007 // third input argument 
0000000000000000000000000000000000000000000000000000000000000003 // length of array data to look at 
0000000000000000000000000000000000000000000000000000000000000001 // array values 
0000000000000000000000000000000000000000000000000000000000000002 // ..... 
0000000000000000000000000000000000000000000000000000000000000003 // ..... 

• Using a struct instead of an array will encode the variables directly into memory in order, since it knows in advance how big the struct is

0x01e58fb4
0000000000000000000000000000000000000000000000000000000000000005
0000000000000000000000000000000000000000000000000000000000000001
0000000000000000000000000000000000000000000000000000000000000002
0000000000000000000000000000000000000000000000000000000000000003
0000000000000000000000000000000000000000000000000000000000000007