Ascii to Hex conversion in Xquery

Question

I have a requirement to convert the ASCII to Hex String using XQuery, Please help to provide any respective reference or code snippets to achieve this functionality, by example I have then string: 1239565447854 and I need convert to hex: 31323339353635343437383534

Answer 1

You can use string-to-codepoints() to get the numeric codepoint for each character. For each codepoint, determine how many times it is divisible by 16 using idiv, and the remainder using the mod operator. For both of those numbers, get their hex value by looking up by position in a sequence of the 16 characters and then join the results:

declare function local:codepoint-to-hex($codepoint as xs:integer) as xs:string {
  let $hex-index := ("0123456789ABCDEF" => string-to-codepoints()) ! codepoints-to-string(.)
  let $base16 := $codepoint idiv 16
  let $remainder := $codepoint mod 16
  return 
    string-join((
      $hex-index[$base16 + 1],
      if ($remainder = 0) 
      then ()
      else $hex-index[$remainder + 1]
      ), "")
};

declare function local:string-to-hex($str as xs:string) as xs:string {
  string-join( string-to-codepoints($str) ! local:codepoint-to-hex(.), "")
};

local:string-to-hex('1239565447854')