delphi 如何快速读取文本文件
You may try this:
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function R(const FileName: string): string; var M: TFileStream; begin M := TFileStream.Create(FileName, fmOpenRead); try SetLength(Result, M.Size); M.Read(Result[1], M.Size); finally M.Free; end; end; |
Solve 2:
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As an alternative to Christian's suggestion, you can also use a memory-mapped file:
function MMFileToString(const AFilename: string): string; var hFile: THandle; hFileMap: THandle; hiSize: DWORD; loSize: DWORD; text: string; view: pointer; begin Result := ''; if AFilename = '' then Exit; if not FileExists(AFilename) then Exit; {Open the file} hFile := CreateFile(PChar(AFilename), GENERIC_READ, FILE_SHARE_READ, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); if hFile <> INVALID_HANDLE_VALUE then begin loSize := GetFileSize(hFile, @hiSize); {File was opened successfully, now map it:} hFileMap := CreateFileMapping(hFile, nil, PAGE_READONLY, hiSize, loSize, 'TextForString'); if (hFileMap <> 0) then begin if (GetLastError() = ERROR_ALREADY_EXISTS) then begin MessageDlg('Mapping already exists - not created.', mtWarning, [mbOk], 0); CloseHandle(hFileMap) end else begin try {File mapped successfully, now map a view of the file into the address space:} view := MapViewOfFile(hFileMap, FILE_MAP_READ, 0, 0, 0); if (view <> nil) then begin {View mapped successfully} CloseHandle(hFile); {Close file handle - as long is view is open it will persist} SetLength(Result, loSize); Move(view^, Result[1], loSize); end else MessageDlg('Unable to map view of file. ' + SysErrorMessage(GetLastError), mtWarning, [mbOk], 0); finally UnmapViewOfFile(view); {Close view} CloseHandle(hFileMap); {Close mapping} end end end else begin MessageDlg('Unable to create file mapping. ' + SysErrorMessage(GetLastError), mtWarning, [mbOk], 0); end; end else begin MessageDlg('Unable to open file. ' + SysErrorMessage(GetLastError), mtWarning, [mbOk], 0); end; end; |
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本文来源：来自网络 作者：佚名
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