dim src as string // input

dim theRegex as Regex
dim theRegexMatch as RegexMatch
dim result, infoCharset, encodedPart as string
dim theStart as Integer

if instr(src, "=?") > 0 then
  theRegex = new Regex
  theRegex.Options.Greedy = false
  theRegex.searchPattern = "(.*)=\?(.+)\?(Q|B)\?(.+)\?="
  theRegexMatch = theRegex.search(src)
  while theRegexMatch <> nil
    theStart = theRegexMatch.subExpressionStartB(0) + len(theRegexMatch.subExpressionString(0))
    
    result = result + theRegexMatch.subExpressionString(1)
    infoCharset = theRegexMatch.subExpressionString(2)
    encodedPart = theRegexMatch.subExpressionString(4)
    if theRegexMatch.subExpressionString(3) = "B" then
      encodedPart = DecodeBase64(encodedPart)
    elseif theRegexMatch.subExpressionString(3) = "Q" then
      encodedPart = DecodeQuotedPrintable(encodedPart)
    end if
    if right(result, 1) = " " then
      result = mid(result, 1, len(result)-1)
    end if
    encodedPart = encodedPart.DefineEncoding(GetInternetTextEncoding(infoCharset))
    result = result + encodedPart
    
    theRegex.SearchStartPosition = theStart
    theRegexMatch = theRegex.search()
  wend
  
  result = result + mid(src, theStart+1)
  
else
  result = src
end if
// theRegexMatch = theRegex.search

msgbox result