You talk about "text string" and "binary string", but I really don't know what those phrases mean to you.

I'll guess that what you have is a string of octets - characters in the range 0x00 .. 0xff - and that you want to increment that string from the right-hand end as if it were a base 256 number. If that is the case, this will do it:

  $value =~ s{(^|[^\xff])(\xff*)$}{ chr(ord($1) + 1) . ("\x00" x lengt
+h($2)) }e;

[download]

Note that if the string has characters that are not octets - ie if it has Unicode characters with codepoints greater than 255 - then this will not achieve the same thing. If that is possible, you will need to explain more precisely what the possible inputs are.

Also, if the string consists of octets intended to represent the utf8-encoding of a character string, this can create strings that represent malformed utf8. If that would be a problem, you will need to explain more precisely what the possible inputs and valid outputs are.

In reply to Re^3: Add 1 to an arbitrary-length binary string by hv
in thread Add 1 to an arbitrary-length binary string by einhverfr

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