将字符串转换为bytes32以用于实体合约调用

Question

How can I convert a Perl string to bytes32 like the java function below:

public static Bytes32 stringToBytes32(String string) {
    byte[] byteValue = string.getBytes();
    byte[] byteValueLen32 = new byte[32];
    System.arraycopy(byteValue, 0, byteValueLen32, 0, byteValue.length);
    return new Bytes32(byteValueLen32);
}

Is there any module available in CPAN to do this?

Answer 1

It looks like all this function does it to encode a string into bytes, then truncate/pad it so the result is exactly 32 bytes long.

The first part may be tricky because according to the documentation :

 public byte[] getBytes() 

Encodes this String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.

The behavior of this method when this string cannot be encoded in the default charset is unspecified.

Perl doesn't really have a concept of a "default charset", but if you're willing to settle for UTF-8, it's not hard:

sub stringToBytes32 {
    my ($str) = @_;
    utf8::encode $str;
    return pack 'a32', $str;
}

(See Encode::encode if you need a different encoding.)

pack is handy for producing data in binary formats. Here we use it to truncate/pad to 32 bytes.