关于 Delphi 中流的使用:分割与合并文件的函数

unit
Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class
(TForm)
Button1: TButton;
Button2: TButton;
procedure
Button1Click(Sender: TObject);
procedure
Button2Click(Sender: TObject);
end
;
var
Form1: TForm1;
implementation
{$R *.dfm}
//分割文件的函数
{参数 1 是要分割的文件名; 参数 2 是要风格文件的大小, 单位是 KB}
{分割后的文件名扩展名用序号替换}
function
SplitFile(const
FileName: string
; Size: Cardinal): Boolean;
var
fStream: TFileStream; {原始文件}
toStream: TMemoryStream; {分文件}
p,i: Integer; {p 记录当前指针位置; i 记录这是第几个分的文件}
begin
Result := False;
Size := Size * 1024
; {把大小的单位转换为字节}
fStream := TFileStream.Create(FileName, fmOpenRead);
p := 0
;
i := 0
;
toStream := TMemoryStream.Create;
while
p < fStream.Size do
begin
toStream.Clear; {清空上次数据}
fStream.Position := p; {放好指针位置}
if
fStream.Size-p < Size then
Size := fStream.Size-p; {最后一个时, 有多少算多少}
toStream.Copyfrom(fStream, Size); {复制}
toStream.SaveToFile(FileName + '.'
+ IntToStr(i)); {保存}
Inc(i);
p := p + Size;
end
;
fStream.Free;
toStream.Free;
Result := True;
end
;
//合并文件, 参数是其中一个分文件名
function
MergeFile(const
FileName: string
): Boolean;
var
ms: TMemoryStream; {读取分文件}
fs: TFileStream; {合并后的文件}
path: string
;
i: Integer;
begin
path := ChangeFileExt(FileName,''
); {去掉序号扩展名}
ShowMessage(path);
i := 0
;
ms := TMemoryStream.Create;
fs := TFileStream.Create(path, fmCreate);
while
FileExists(path + '.'
+ IntToStr(i)) do
begin
ms.LoadfromFile(path + '.'
+ IntToStr(i));
fs.Copyfrom(ms, 0
); {TFileStream 不需要 SetSize; 但如果用 TMemoryStream 就需要}
Inc(i);
end
;
ms.Free;
fs.Free;
end
;