新手，请教一个读取文本文件的问题
现有一个log文件，内容大致如下:
2012-09-29 10:34:51==>INFO: 时间戳:Wed Nov 18 09:56:00 2011
2012-09-29 10:34:51==>INFO:
----------------------------------
2012-09-29 10:35:08==>D: 开始
2012-09-29 10:35:08==>D: Input= 2140^401012^1057^^|^
2012-09-29 10:35:08==>D: InputPara：2140^401012^1057^^|^
2012-09-29 10:35:09==>D: Out：返回值为：0，数据为：201209291035391590^71077247|^
2012-09-29 10:35:09==>D: 结束
----------------------------------
2012-09-29 10:35:15==>: 开始
2012-09-29 10:35:15==>D: Input= 2210^401012^1057^^|^
2012-09-29 10:35:15==>D: InputParam：2210^401012^1057^^|^
2012-09-29 10:35:15==>D: Out：返回值为：-1，数据为：无效的输入参数
2012-09-29 10:35:15==>D: 结束

请教怎么样处理得到读取文本文件后返回结果：
2140^401012^1057^^|^
成功
2210^401012^1057^^|^
失败
[最优解释]
说清楚点。。没看懂
[其他解释]
返回值0表示成功，非0表示失败？
[其他解释]
没看懂……什么意思？
[其他解释]
是取 Input= 2140^401012^1057^^
[其他解释]
^后的值吧，题目真看不怎么明白。
[其他解释]
调入内存，一行一行地读取。用POST()函数查找有用的行，读取相关信息即可。
当前行中包含'input='就取它的后20个字符。
当前行中包含'Out：返回值为：'就取它面的后1位，如果为0则成功，否则就不成功。

[其他解释]
贴个delphi5开发人员指南的例子给你
uses MemMap
//以下为MemMap代码
unit MemMap;

interface

uses Windows,SysUtils,Classes;

type
EMMFError = class(Exception);

TMemMapFile = class
private
FFileName: string;
FSize: LongInt;
FFileSize: LongInt;
FFileMod: Integer;
FFileHandle: Integer;
FMapHandle: Integer;
FData: PByte;
FMapNow: Boolean;

procedure AllocFileHandle;
procedure AllocFileMapping;
procedure AllocFileView;
function GetSize: LongInt;
public
constructor Create(FileName: string;FileMod: Integer;Size: Integer;MapNow: Boolean);virtual;
destructor Destroy;override;
procedure FreeMapping;
property Data: PByte read FData;
property Size: LongInt read FSize;
property FileName: string read FFileName;
property FileHandle: Integer read FFileHandle;
property MapHandle: Integer read FMapHandle;
end;

implementation

{ TMemMapFile }

procedure TMemMapFile.AllocFileHandle;
begin
if FFileMod = fmCreate then
FFileHandle := FileCreate(FFileName)
else

FFileHandle := FileOpen(FFileName,FFileMod);

if FFileHandle = 0 then
raise EMMFError.Create('Failed to open or create file');
end;

procedure TMemMapFile.AllocFileMapping;
var
ProtAttr: DWORD;
begin
if FFileMod = fmOpenRead then
ProtAttr := PAGE_READONLY
else
ProtAttr := PAGE_READWRITE;

FMapHandle := CreateFileMapping(FFileHandle,nil,ProtAttr,0,FSize,nil);

if FMapHandle = 0 then
raise EMMFError.Create('Failed to create file mapping');
end;

procedure TMemMapFile.AllocFileView;
var
Access: LongInt;
begin
if FFileMod = fmOpenRead then
Access := FILE_MAP_READ
else
Access := FILE_MAP_ALL_ACCESS;

FData := MapViewOfFile(FMapHandle,Access,0,0,FSize);

if FData = nil then
raise EMMFError.Create('Failed to map view of file');
end;

constructor TMemMapFile.Create(FileName: string; FileMod, Size: Integer;
MapNow: Boolean);
begin
FFileName := FileName;
FFileMod := FileMod;
FMapNow := MapNow;

AllocFileHandle;

FFileSize := GetFileSize(FFileHandle,nil);
FSize := Size;

try
AllocFileMapping;
except
on EMMFError do
begin
CloseHandle(FFileHandle);
FFileHandle := 0;
raise;
end;
end;

if FMapNow then
AllocFileView;
end;

destructor TMemMapFile.Destroy;
begin
if FFileHandle <> 0 then
CloseHandle(FFileHandle);

if FMapHandle <> 0 then
CloseHandle(FMapHandle);

FreeMapping;
inherited Destroy;
end;

procedure TMemMapFile.FreeMapping;
begin
if FData <> nil then
begin
UnmapViewOfFile(FData);
FData := nil;
end;
end;

function TMemMapFile.GetSize: LongInt;
begin
if FSize <> 0 then
Result := FSize
else
Result := FFileSize;
end;

end.
//引用单元到此为止
//以下为查找内容
var
MemMapFile: TMemMapFile;
FounStr: PChar;
FName: string;
FindString: string;
begin
FName := 'C:\aa.log';//你要查找的文件全名
MemMapFile := TMemMapFile.Create(FName,fmOpenRead,0,True);
try
FindString := 'aaaa'; //你要找的字符
FounStr := StrPos(PChar(MemMapFile.Data),PChar(FindString));

if FounStr <> nil then
begin
//说明找到了
end;
finally
MemMapFile.Free;
end;

end;