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

;

//测试分割

procedure

TForm1.Button1Click(Sender: TObject);

begin

SplitFile('c:/temp/test.txt'
, 10
);

end

;

//测试合并

procedure

TForm1.Button2Click(Sender: TObject);

begin

MergeFile('c:/temp/test.txt.0'
);

end

;

end

.