Understanding Bytes16 Representation in Solidity

Question

I have a simple function printing byte a byte the value of a bytes16 0x20010db8000000000000000000000001 and I get the following result.

['0x20', '0x01', '0x0d', '0xb7', '0xff', '0xff', '0xff', '0x65' ]

[ '0x20', '0x7e', '0x22', '0x36', '0x66', '0xc0', '0x00', '0x00' ]

It should not be??

['0x20', '0x01', '0x0d', '0xb8', '0x00', '0x00', '0x00', '0x00' ]

[ '0x00', '0x00', '0x00', '0x00', '0x00', '0x00', '0x00', '0x01' ]

Why it is not??

Here the code:

function print1(bytes16 a) public 
returns (bytes1,bytes1,bytes1,bytes1,bytes1,bytes1,bytes1,bytes1){
return (a[0],a[1],a[2],a[3],a[4],a[5],a[6],a[7]);}


function print2(bytes16 a) public returns
(bytes1,bytes1,bytes1,bytes1,bytes1,bytes1,bytes1,bytes1){
return (a[8],a[9],a[10],a[11],a[12],a[13],a[14],a[15]);}    

Step to reproduce:

print1(0x20010db8000000000000000000000001);
print2(0x20010db8000000000000000000000001);

Answer 1

I tested your code with Remix. But it works fine. If you tested using truffle (javascript test file), then you should use print1("0x20010db8000000000000000000000001"), do not forget "". I got similar issue with byte1 array as here.

And this is truffle result with your code,

plus, both print1 and print2, you better add "pure" to avoid warning, something like..

function print1(bytes16 a) public pure