1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/framework/env/encode/mime/unstructured_header_line.lua	Sun Oct 25 12:00:00 2009 +0100
     1.3 @@ -0,0 +1,71 @@
     1.4 +function encode.mime.unstructured_header_line(key, value)
     1.5 +  if not value then
     1.6 +    return ""
     1.7 +  end
     1.8 +  local charset = "UTF-8"  -- TODO: support other charsets
     1.9 +  local key_length = #key + #(": ")
    1.10 +  if string.find(value, "^[\t -~]*$") then
    1.11 +    local need_encoding = false
    1.12 +    local parts = { key, ": " }
    1.13 +    local line_length = key_length
    1.14 +    local first_line = true
    1.15 +    for spaced_word in string.gmatch(value, "[\t ]*[^\t ]*") do
    1.16 +      if #spaced_word + line_length > 76 then
    1.17 +        if first_line or #spaced_word > 76 then
    1.18 +          need_encoding = true
    1.19 +          break
    1.20 +        end
    1.21 +        parts[#parts+1] = "\r\n"
    1.22 +        line_length = 0
    1.23 +      end
    1.24 +      parts[#parts+1] = spaced_word
    1.25 +      line_length = line_length + #spaced_word
    1.26 +      first_line = false
    1.27 +    end
    1.28 +    if not need_encoding then
    1.29 +      parts[#parts+1] = "\r\n"
    1.30 +      return table.concat(parts)
    1.31 +    end
    1.32 +    charset = "US-ASCII"
    1.33 +  end
    1.34 +  local parts = { key, ": " }
    1.35 +  local line_length
    1.36 +  local opening = "=?" .. charset .. "?Q?"
    1.37 +  local closing = "?="
    1.38 +  local indentation = ""
    1.39 +  for i = 1, key_length do
    1.40 +    indentation = indentation .. " "
    1.41 +  end
    1.42 +  local open = false
    1.43 +  for char in string.gmatch(value, ".") do
    1.44 +    local encoded_char
    1.45 +    if string.find(char, "^[0-9A-Za-z%.%-]$") then
    1.46 +      encoded_char = char
    1.47 +    else
    1.48 +      local byte = string.byte(char)
    1.49 +      if byte == 32 then
    1.50 +        encoded_char = "_"
    1.51 +      else
    1.52 +        encoded_char = string.format("=%02X", byte)
    1.53 +      end
    1.54 +    end
    1.55 +    if open and line_length + #encoded_char > 76 then
    1.56 +      parts[#parts+1] = closing
    1.57 +      parts[#parts+1] = "\r\n"
    1.58 +      parts[#parts+1] = indentation
    1.59 +      open = false
    1.60 +    end
    1.61 +    if not open then
    1.62 +      parts[#parts+1] = opening
    1.63 +      line_length = key_length + #opening + #closing
    1.64 +      open = true
    1.65 +    end
    1.66 +    parts[#parts+1] = encoded_char
    1.67 +    line_length = line_length + #encoded_char
    1.68 +  end
    1.69 +  if open then
    1.70 +    parts[#parts+1] = "?="
    1.71 +  end
    1.72 +  parts[#parts+1] = "\r\n"
    1.73 +  return table.concat(parts)
    1.74 +end