{  ==============================================================================  MapTextfiles - Release 99/1  14.03.1999  for Delphi 4, should also run with Delphi 3  ------------------------------------------------------------------------------  MapTextfiles is FREEWARE. Freeware means, that you can use this software  without paying anything for it, but it is not public domain! This software  is protected through the law of the Federal Republic of Germany, the European  Union and other countries.  (C)1999 by Peter Hellinger Software, All rights are reserved.  Peter Hellinger Software, Zerzabelshofstrasse 41, D-90480 N黵nberg  email: mail@helli.de  homepage: http://www.helli.de  ==============================================================================  Installation:  Copy MAPTEXTFILE.PAS into your library path. Use ist. 8-)  ------------------------------------------------------------------------------  In Delphi you have many ways to manipulate text files. But all of these have  a handicap: You must read the whole file (StringList) or you can only access  data sequential (Assign/Readln).  The Windows API provides the so called Memory Mapped Files. Windows self  uses MMFs to load EXE or DLL. Therefore the mechanism is very efficient, but  simple to handle. The only handicap is, that you must know the size of the  file before you access it. This means for typical text files, that the  operation is normally limited to read from the file or manipulate inside.  The class TMapTextfile wraps the neccesary API calls and povides efficent  functions for accessing the data.  TMapTextfiles provides the following properties and methods:  Methodes:  =========  Create         Creates an instace of the class  Destroy        Destroys the instance  Open           Opens a file as a memory mapped file.  filename = name of the file  mode =     open mode:  mmRead =      Open only for read  mmReadWrite = Open for read and wrie  Returns INVALID_HANDLE_VALUE if the file not exist.  If the result > 0 all is OK.  NOTE:  1. The file must exist!  2. You cannot write behind the end of the file.  Close          Close the memory mapped file and frees all handles.  EndOfFile      Returns TRUE, if the End of the file is reached.  GetSize        Returns the Size of the file in Bytes  GetPos         Returns the actual file read/write position  NOTE: Position 0 is the start of the file  SetPos         Sets the actual read/write position  NOTE: Position 0 is the start of the file  ReadChar       Reads a character from the actual read/write position.  The r/w position is incremented.  ReadString     Returns a string, starting at the actual r/w position.  The string is delimited by characters < SPACE, but not  by ESC (#27) and TAB. The r/w position moves to the  end of the string, delimiter chararcters are skiped.  ReadLn         Same as ReadSring, but as a Procedure.  ReadCharAt     Reads a charater from an arbitray possition.  The r/w position is NOT moved!  pos = position to read from (0 = start of the file!)  ReadChars      Reads a line of charactes from the MMF.  The r/w position is NOT moved!  str = The buffer to read to  pos = position to read from (0 = Start of the file!)  len = number of characters to read.  ReadStringAt   Returns a string, starting at an arbitray possition.  The string is delimited by characters < SPACE, but not  by ESC (#27) and TAB. The r/w position is NOT moved.  FindString     Findes a substring in the MMF and Returns the position.  str = rhe substring to search for  pos = position to start the search (0 = start of the file)  max = position to end the search. If this is 0 or less  then 0 the end of the file is the limit.  Returns the position of the substring or -1 if the  substring is not found.  FindWildCard   Same as Findstring, but supports wildcard search.  str =   the substring to search for  pos =   position to start the search (0 = start of the file)  max =   position to end the search. If this is 0 or less  then 0 the end of the file is the limit.  wild =  the character used as wildcard (i.e. "*")  joker = the character used as joker (i.e. "?")  Returns the position of the substring or -1 if the  substring is not found.  ReadBytes      Reads a number of bytes to a anonymous variable.  The r/w position is NOT moved!  b =   the anonymous variable  pos = position to read from (0 = start of the file)  len = number of bytes to read.  WriteBytes     Writes a number of bytes to the file.  NOTE: You can not write behind the end of the file!!!  b =   the anonymous variable  pos = position to write to (0 = start of the file)  len = number of bytes to write  ==============================================================================}unit uMapTextfile;interfaceuses Classes, Windows;type  tMapMode = ( mmRead, mmReadWrite );type  TMapTextfile = class  private    f_file : THandle;    f_MMF : THandle;    f_size : INTEGER;    f_view : PByte;    f_data : PChar;    f_pos : INTEGER;    f_open : BOOLEAN;    function CalcPos( pos : INTEGER ) : PChar;  public    constructor Create;    destructor Destroy; override;    function Open( const filename : string; mode : tMapMode ) : INTEGER;    procedure Close;    function ReadChar : CHAR;    function ReadString : string;    procedure ReadLn( var str : string );    function ReadCharAt( pos : LONGINT ) : CHAR;    procedure ReadChars( str : PChar; pos, len : LONGINT );    function ReadStringAt( pos : LONGINT ) : string;    function GetSize : LONGINT;    function GetPos : LONGINT;    procedure SetPos( pos : LONGINT );    function EndOfFile : BOOLEAN;    function FindString( const str : string; pos, max : INTEGER ) : INTEGER;    function FindWildCard( const str : string; pos, max : INTEGER;      wild, joker : CHAR ) : INTEGER;    procedure ReadBytes( var b; pos, len : LONGINT );    procedure WriteBytes( var b; pos, len : LONGINT );  end;implementationconstructor TMapTextfile.Create;begin  f_open := FALSE;end;function TMapTextfile.Open( const filename : string; mode : tMapMode )  : INTEGER;var  m1, m2, m3 : CARDINAL;begin  f_open := FALSE;  if mode = mmRead then  begin    m1 := GENERIC_READ;    m2 := PAGE_READONLY;    m3 := FILE_MAP_READ;  end else begin    m1 := GENERIC_READ + GENERIC_WRITE;    m2 := PAGE_READWRITE;    m3 := FILE_MAP_WRITE;  end;  f_file := CreateFile( PChar( filename ), m1, FILE_SHARE_READ, nil,    OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0 );  if f_file = INVALID_HANDLE_VALUE then  begin    Result := INVALID_HANDLE_VALUE;    EXIT;  end;  try    f_size := GetFileSize( f_file, nil );    f_MMF := CreateFileMapping( f_file, nil, m2, 0, f_size, nil );    if f_MMF = 0 then    begin      Result := -1;      EXIT;    end;  finally    CloseHandle( f_file );  end;  try    f_view := MapViewOfFile( f_MMF, m3, 0, 0, f_size );    if f_view = nil then    begin      Result := -1;      EXIT;    end;  finally    CloseHandle( f_MMF );  end;  f_data := PChar( f_view );  f_pos := 0;  f_open := TRUE;  Result := 0;end;destructor TMapTextfile.Destroy;begin  if f_open then    Close;  inherited;end;procedure TMapTextfile.Close;begin  if f_open then  begin    UnmapViewOfFile( f_view );    f_open := FALSE;  end;end;function TMapTextfile.CalcPos( pos : INTEGER ) : PChar;begin  Result := nil;  if f_open then  begin    if pos < 0 then      pos := 0;    if pos > f_size then      pos := f_size;    Result := PChar( LONGINT( f_view ) + pos );  end;end;function TMapTextfile.ReadChar : CHAR;begin  Result := #0;  if f_open then  begin    f_data := PChar( LONGINT( f_view ) + f_pos );    Result := f_data^;    INC( f_pos );  end;end;function TMapTextfile.ReadString : string;begin  Result := ‘‘;  if f_open then  begin    f_data := PChar( LONGINT( f_view ) + f_pos );    while ( f_pos < f_size ) do    begin      case f_data^ of        #0 .. #31 :          case f_data^ of            #9, #27 :              Result := Result + f_data^; // Tab und Escape weiterreichen            #10 :              begin                INC( f_pos );                EXIT;              end;            #13 :              begin // Carriage Return terminiert                INC( f_pos );                INC( f_data );                if f_data^ = #10 then                  INC( f_pos );                EXIT;              end;          end;      else        Result := Result + f_data^;      end;      INC( f_pos );      INC( f_data );    end;  end;end;function TMapTextfile.ReadCharAt( pos : LONGINT ) : CHAR;begin  if f_open then    Result := CalcPos( pos )^  else    Result := #0;end;procedure TMapTextfile.ReadChars( str : PChar; pos, len : LONGINT );var  i : INTEGER;  p : PChar;begin  if f_open then  begin    if len <= 0 then      EXIT;    i := 0;    p := CalcPos( pos );    while ( i <= f_size ) and ( i <= len ) do    begin      str^ := p^;      INC( str );      INC( p );      INC( i );    end;  end;end;procedure TMapTextfile.ReadBytes( var b; pos, len : LONGINT );var  p : PChar;begin  if f_open then  begin    p := CalcPos( pos );    Move( p^, b, len );  end;end;procedure TMapTextfile.WriteBytes( var b; pos, len : LONGINT );var  p : PChar;begin  if f_open then  begin    p := CalcPos( pos );    Move( b, p^, len );  end;end;function TMapTextfile.ReadStringAt( pos : LONGINT ) : string;var  i : INTEGER;  p : PChar;begin  Result := ‘‘;  if f_open then  begin    p := CalcPos( pos );    i := 0;    while ( i <= f_size ) do    begin      case p^ of        #0 .. #31 :          case p^ of            #9, #27 :              Result := Result + p^; // Tabs und Escape weiterreichen            #10, #13 :              EXIT; // Linefeed and Carriage Return terminiert          end;      else        Result := Result + p^;      end;      INC( p );    end;  end;end;procedure TMapTextfile.ReadLn( var str : string );begin  str := ReadString;end;function TMapTextfile.GetSize : LONGINT;begin  if f_open then    Result := f_size  else    Result := -1;end;function TMapTextfile.GetPos : LONGINT;begin  if f_open then    Result := f_pos  else    Result := -1;end;procedure TMapTextfile.SetPos( pos : LONGINT );begin  if f_open then  begin    if pos < 0 then      pos := 0;    if pos > f_size then      pos := f_size;    f_pos := pos;  end;end;function TMapTextfile.EndOfFile : BOOLEAN;begin  if f_open then    Result := f_pos >= f_size  else    Result := TRUE;end;function TMapTextfile.FindString( const str : string; pos, max : INTEGER )  : INTEGER;var  s, l1, j : INTEGER;  p, x : PChar;begin  Result := -1;  if f_open then  begin    if max <= 0 then      max := f_size;    if pos < 0 then      pos := f_pos;    if pos > max then      EXIT;    x := PChar( str );    p := PChar( f_view );    l1 := 0;    while ( x[ l1 ] > #0 ) do      INC( l1 );    if ( l1 > 0 ) then    begin      s := pos;      repeat (* 1 *)        j := 0;        while ( s + j < max ) and ( j < l1 ) and ( x[ j ] = p[ s + j ] ) do        begin          INC( j );          if ( j = l1 ) then          begin            Result := s;            EXIT;          end;        end;        INC( s );      until s >= f_size;    end;  end;end;function TMapTextfile.FindWildCard( const str : string; pos, max : INTEGER;  wild, joker : CHAR ) : INTEGER;var  s, l1, j : INTEGER;  p, x : PChar;begin  Result := -1;  if f_open then  begin    if max <= 0 then      max := f_size;    if pos < 0 then      pos := f_pos;    if pos > max then      EXIT;    x := PChar( str );    p := PChar( f_view );    l1 := 0;    while ( x[ l1 ] > #0 ) do      INC( l1 );    if ( l1 > 0 ) then    begin      s := pos;      repeat (* 1 *)        j := 0;        while ( s + j < max ) and ( j < l1 ) and          ( ( x[ j ] = p[ s + j ] ) or ( x[ j ] = joker ) ) do        begin          INC( j );          if ( x[ j ] = wild ) or ( j >= l1 ) then          begin            Result := s;            EXIT;          end;        end;        INC( s );      until s >= f_size;    end;  end;end;end.