Find out if IP Address is valid (Views: 27)
Problem/Question/Abstract: Find out if IP Address is valid Answer: function IsWrongIP(ip: string): boolean; var z, i: byte; st: array[1..3] of byte; const ziff = ['0'..'9']; begin st[1] := 0; st[2] := 0; st[3] := 0; z := 0; Result := False; for i := 1 to length(ip) do if ip[i] in ziff then else begin if ip[i] = '.' then begin inc(z); if z < 4 then st[z] := i else begin IsWrongIP := True; exit; end; end else begin IsWrongIP := True; exit; end; end; if (z <> 3) or (st[1] < 2) or (st[3] = length(ip)) or (st[1] + 2 > st[2]) or (st[2] + 2 > st[3]) or (st[1] > 4) or (st[2] > st[1] + 4) or (st[3] > st[2] + 4) then begin IsWrongIP := True; exit; end; z := StrToInt(copy(ip, 1, st[1] - 1)); if (z > 255) or (ip[1] = '0') then begin IsWrongIP := True; exit; end; z := StrToInt(copy(ip, st[1] + 1, st[2] - st[1] - 1)); if (z > 255) or ((z <> 0) and (ip[st[1] + 1] = '0')) then begin IsWrongIP := True; exit; end; z := StrToInt(copy(ip, st[2] + 1, st[3] - st[2] - 1)); if (z > 255) or ((z <> 0) and (ip[st[2] + 1] = '0')) then begin IsWrongIP := True; exit; end; z := StrToInt(copy(ip, st[3] + 1, length(ip) - st[3])); if (z > 255) or ((z <> 0) and (ip[st[3] + 1] = '0')) then begin IsWrongIP := True; exit; end; end; |