IP2Loc_DBInterface.pas

 ////////////////////////////////////////////////
// Unit      : IP2Loc_DBInterface.pas           //
// Version   : 8.2.0                            //
// Date      : April 2023                        //
// Translator: IP2Location                      //
// Email     : support@ip2location.com          //
// License   : MIT                              //
 ////////////////////////////////////////////////

unit IP2Loc_DBInterface;

interface

uses Windows,SysUtils;

type
 TIP2Location_mem_type =(IP2LOCATION_FILE_IO,IP2LOCATION_CACHE_MEMORY,IP2LOCATION_SHARED_MEMORY);

 Tin6_addr_local = record
 case integer of 
 0:(addr8  :array [0..15] of byte);
 1:(addr16 :array [0..8]  of byte);
 end;

 function  IP2Location_readIPv6Address(handle:integer;position:Cardinal):Tin6_addr_local;
 function  IP2Location_read32(handle:integer;position:Cardinal):Cardinal;
 function  IP2Location_read8(handle:integer;position:Cardinal):Byte;
 function  IP2Location_readStr(handle:integer;position:Cardinal):PChar;
 function  IP2Location_readFloat(handle:integer;position:Cardinal):Single;
 function  IP2Location_DB_set_file_io():Cardinal;
 function  IP2Location_DB_set_memory_cache(filehandle:integer):integer;
 function  IP2Location_DB_set_shared_memory(filehandle:integer):integer;
 function  IP2Location_DB_close(filehandle:integer):integer;
 procedure IP2Location_DB_del_shm();

implementation


const
IP2LOCATION_SHM ='/IP2location_Shm';
{$IFDEF POSIX}
MAP_ADDR =4194500608;
{$ENDIF}

var
 DB_access_type:TIP2Location_mem_type=IP2LOCATION_FILE_IO;
 cache_shm_ptr :pointer; 
 shm_fd        :integer;

function IP2Location_DB_Load_to_mem(filehandle:integer;memory:pointer;size:int64):integer;
begin
 result:=0;
 if filehandle = -1 then begin result:=-1 ; exit; end;
 FileSeek(filehandle,0,0);
 if  FileRead(filehandle,memory^,size)=0 then result:=-1;
end;

//Description: set the DB access method as memory cache and read the file into cache
function IP2Location_DB_set_memory_cache(filehandle:integer):integer;
var _size:integer;
begin
 DB_access_type:=IP2LOCATION_FILE_IO;
 result:=-1;
 _size:=GetFileSize(filehandle,nil);
  if (filehandle<>-1) and (_size<>-1) then
   begin
    cache_shm_ptr:=AllocMem(_size);
     if assigned(cache_shm_ptr) and (IP2Location_DB_Load_to_mem(filehandle,cache_shm_ptr,_size)<>-1) then
      begin
       result:=0;
         DB_access_type:=IP2LOCATION_CACHE_MEMORY;
      end;
   end;
end;

//Description: set the DB access method as shared memory
function IP2Location_DB_set_shared_memory(filehandle:integer):integer;
var 
_size:integer;
DB_Loaded:boolean;
begin
 DB_access_type:=IP2LOCATION_FILE_IO;
 result:=-1;
 _size:=GetFileSize(filehandle,nil);
  if (filehandle <>-1) and (_size<>-1) then
   begin
      shm_fd:=CreateFileMapping(
                 INVALID_HANDLE_VALUE,
                 nil,
                 PAGE_READWRITE,
                 0,
                 _size+1,
                 PChar(IP2LOCATION_SHM));
      DB_loaded := (GetLastError = ERROR_ALREADY_EXISTS);
      if shm_fd <>0 then
        cache_shm_ptr := MapViewOfFile(
            shm_fd,
            FILE_MAP_WRITE,
            0, 
            0,
            0)else exit;
       if not(DB_Loaded) and (IP2Location_DB_Load_to_mem(filehandle,cache_shm_ptr,_size)<>-1) then
        begin
         DB_access_type := IP2LOCATION_SHARED_MEMORY;
         result:=0;
        end
       else
       begin
        UnmapViewOfFile(cache_shm_ptr);
        CloseHandle(shm_fd);
          end;
   end;
end;

//Close the corresponding memory, based on the opened option. 
function IP2Location_DB_close(filehandle:integer):integer;
begin
 if filehandle<>0 then CloseHandle(filehandle);
 if assigned(cache_shm_ptr) then
  case DB_access_type of
   IP2LOCATION_CACHE_MEMORY : FreeMem(cache_shm_ptr);
   IP2LOCATION_SHARED_MEMORY: begin UnmapViewOfFile(cache_shm_ptr);CloseHandle(shm_fd);end;
  end;
 DB_access_type := IP2LOCATION_FILE_IO;
 result:=0;
 end;

 function IP2Location_read8(handle:integer;position:Cardinal):byte;
 begin
  result:=0;
      if (DB_access_type = IP2LOCATION_FILE_IO) and (handle <> 0) then
       begin
        FileSeek(handle,position-1,0);
        FileRead(handle,result,1);
       end
      else
      result:=PByteArray(cache_shm_ptr)^[position-1];
 end;

function IP2Location_read32(handle:integer;position:cardinal):cardinal;
var byte1,byte2,byte3,byte4:Byte;
begin
 if (DB_access_type = IP2LOCATION_FILE_IO) and (handle <> 0) then
     begin
      FileSeek(handle,position-1,0);
      FileRead(handle,byte1,1);
      FileRead(handle,byte2,1);
      FileRead(handle,byte3,1);
      FileRead(handle,byte4,1);
     end
 else
   begin
      byte1:=PByteArray(cache_shm_ptr)^[position-1];
      byte2:=PByteArray(cache_shm_ptr)^[position];
      byte3:=PByteArray(cache_shm_ptr)^[position+1];
      byte4:=PByteArray(cache_shm_ptr)^[position+2];
     end;
    result:= (byte4 shl 24) or (byte3 shl 16) or (byte2 shl 8) or byte1;
  end;

function IP2Location_readStr(handle:integer;position:cardinal):PChar;
var _size:byte;P_In:PAnsiChar;
begin
 result:='';
 if (DB_access_type = IP2LOCATION_FILE_IO) and (handle <> 0) then 
  begin
   FileSeek(handle,position,0);
   FileRead(handle,_size,1);
   Result:=AllocMem(_size+1);
   FileRead(handle,result^,_size);
  end
  else
  begin
   _size:=PByteArray(cache_shm_ptr)^[position];
   Result:=AllocMem(_size+1);
   CopyMemory(result,@PByteArray(cache_shm_ptr)^[position+1],_size);
  end;
 {$IFDEF UNICODE}
  P_IN  :=PAnsiChar(Result);
  Result:=AllocMem(StrLen(P_IN)*2+2);
  MultiByteToWideChar(CP_UTF8,0,P_IN,StrLen(P_IN),Result,StrLen(P_IN));
 {$ENDIF}
end;

function IP2Location_readFloat(handle:integer;position:cardinal):single;
begin
 result:=0.0;
  if (DB_access_type = IP2LOCATION_FILE_IO) and (handle <> 0) then
   begin
    FileSeek(handle,position-1,0);
    FileRead(handle,result,4);
   end
  else
  CopyMemory(@result,@PByteArray(cache_shm_ptr)^[position-1],4);
end;

procedure IP2Location_DB_del_shm();
begin
{$IFDEF POSIX}
{$ENDIF}
end;

function  IP2Location_readIPv6Address(handle:integer;position:Cardinal):Tin6_addr_local;
 var i:integer;
 begin
  with result do 
   for i:=0 to 15 do 
    addr8[i]:=IP2Location_read8(handle, position + (15-i)); 
 end;

function IP2Location_DB_set_file_io():Cardinal;
begin
end;

end.