判断　 ip 范围

场景：关于判断IP范围解决办法

关于判断IP范围
——如何判断一IP是否在某一段IP范围内？及输入是否为合法ip？
数据库中存储ip范围上下界，如；ip_s：10.20.72.2       ip_e：10.20.72.60
（这是最简单的，只有最末位在变）
如输入：10.20.72.5


------解决方案--------------------
unit Functions;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs;

function CheckInternetOnline: boolean; //检查互联网是否在线
function IsIP(S: string): boolean; //判断录入的字符串是否为IP
function GetLocalIP: string; //获取本机IP地址
function GetTheInternetLocalIP: string; //获取外网IP地址


implementation

uses
GetInternetLocalIP,WinInet,Winsock;

//HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

function CheckInternetOnline: boolean; //检查互联网是否在线
var
ConnectState: DWORD;
StateSize: DWORD;
begin
ConnectState := 0;
StateSize := SizeOf(ConnectState);
Result := false;
//Use WinInet.pas;
if InternetQueryOption(nil, INTERNET_OPTION_CONNECTED_STATE, @ConnectState, StateSize) then
Result := (ConnectState and INTERNET_STATE_DISCONNECTED) <> 2;
if Result then
Result := InternetCheckConnection( 'http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome ', 1, 0);
end;

//HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
function IsIP(S: string): boolean; //判断录入的字符串是否为IP
var
S1, S2, S3, S4, sTemp: string;
K, I: integer;
begin
S1 := ' ';
S2 := ' ';
S3 := ' ';
S4 := ' ';
K := 0;
Result := false;
S := Trim(S);
if Length(S) < 7 then exit; //最小的IP长度也是7位0.0.0.0
for I := 0 to Length(S) do
if S[I] = '. ' then
Inc(K);
if K <> 3 then
begin
Result := false;
exit;
end
else
begin
sTemp := S;
for I := Length(sTemp) downto 1 do
if sTemp[I] = '. ' then
Delete(sTemp, I, 1);
for I := Length(sTemp) downto 1 do
if not (sTemp[I] in [ '0 '.. '9 ']) then
begin
Result := false;
exit;
end;
K := Pos( '. ', S);
S1 := Copy(S, 1, K - 1);
Delete(S, 1, K);
K := Pos( '. ', S);
S2 := Copy(S, 1, K - 1);
Delete(S, 1, K);
K := Pos( '. ', S);
S3 := Copy(S, 1, K - 1);
Delete(S, 1, K);
S4 := S;
Result := (StrToInt(S1) > = 0) and (StrToInt(S1) <= 255) and
(StrToInt(S2) > = 0) and (StrToInt(S2) <= 255) and
(StrToInt(S3) > = 0) and (StrToInt(S3) <= 255) and
(StrToInt(S4) > = 0) and (StrToInt(S4) <= 255);
end;
end;
//HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

function GetLocalIP: string; //获取本机IP地址
type
TaPInAddr = array[0..255] of PInAddr; //Use Winsock.pas
PaPInAddr = ^TaPInAddr;
var
phe: PHostEnt;
pptr: PaPInAddr;
Buffer: array[0..63] of char;
i: integer;
GInitData: TWSADATA;
begin
wsastartup($101, GInitData);
result := ' ';
GetHostName(Buffer, SizeOf(Buffer));
phe := GetHostByName(buffer);
if not assigned(phe) then
exit;
pptr := PaPInAddr(Phe^.h_addr_list);
i := 0;
while pptr^[I] <> nil do
begin
result := Result + StrPas(inet_ntoa(pptr^[I]^)) + ', ';
inc(i);
end;
Delete(Result, Length(Result), 1);
wsacleanup;
end;
//HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

function GetTheInternetLocalIP: string; //获取外网IP地址
begin
Result := ' ';
//Use GetInternetLocalIP.pas
if not Assigned(GetInternetLocalIPForm) then
if CheckInternetOnline then
try
Application.CreateForm(TGetInternetLocalIPForm, GetInternetLocalIPForm);
while GetInternetLocalIPForm.TheInternetLocalIP = 'E ' do Application.ProcessMessages;
Result := GetInternetLocalIPForm.TheInternetLocalIP;
if not IsIP(Result) then
Result := ' ';
finally
FreeAndNil(GetInternetLocalIPForm);
end;
end;

end.