Module:IPAddress

--[=[ Functions are not "local", so other modules can require this module and call them directly. We return an object with 3 small stub functions to call the real ones so that the functions can be called from templates also.

Only dotted decimal notation for IPv4 supported. Does not support dotted hexadecimal, dotted octal, or single-number formats (see IPv4#Address_representations).

Unit tests at Module:IPAddress/tests ]=]

function _isIpV6( s )

   local dcolon, groups
   if type( s ) ~= "string"
       or s:len() == 0
       or s:find( "[^:%x]" ) -- only colon and hex digits are legal chars
       or s:find( "^:[^:]" ) -- can begin or end with :: but not with single :
       or s:find( "[^:]:$" )
       or s:find( ":::" )
   then
       return false
   end 
   s, dcolon = s:gsub( "::", ":" )
   if dcolon > 1 then return false end -- at most one ::
   s = s:gsub( "^:?", ":" ) -- prepend : if needed, upper
   s, groups = s:gsub( ":%x%x?%x?%x?", "" ) -- remove valid groups, and count them
   return ( ( dcolon == 1 and groups < 8 ) or ( dcolon == 0 and groups == 8 ) )
       and ( s:len() == 0 or ( dcolon == 1 and s == ":" ) ) -- might be one dangling : if original ended with ::

end

function _isIpV4( s )

   local function legal( n ) return ( tonumber( n ) or 256 ) < 256  and not n:match("^0%d") end-- in lua 0 is true!
   
   if type( s ) ~= "string" then return false end
   local p1, p2, p3, p4 = s:match( "^(%d+)%.(%d+)%.(%d+)%.(%d+)$" ) 
   return legal( p1 ) and legal( p2 ) and legal( p3 ) and legal( p4 )

end

function _isIp( s )

   return _isIpV4( s ) and "4" or _isIpV6( s ) and "6"

end

local p = {}

function p.isIpV6(frame) return _isIpV6( frame.args[ 1 ] ) and "1" or "0" end function p.isIpV4(frame) return _isIpV4( frame.args[ 1 ] ) and "1" or "0" end function p.isIp(frame) return _isIp( frame.args[ 1 ] ) or "" end

return p