0x00-0x8f 跳到0xb0再讀到EOF並把所取得的BYTES寫到新檔案
-------- Original Message --------
Subject: [PerlChina] Re: 16进制文件操作
From: perlw01f <p3r1w01f@gmail.com>
To: PerlChina Mongers 讨论组 <perlchina@googlegroups.com>
Date: 8/8/2009 10:42
> 谢谢
> perldoc -f seek的结论貌似跟这个不一样 ？
>
> seek FILEHANDLE,POSITION,WHENCE
> Sets FILEHANDLE's position, just like the "fseek" call of
> "stdio". FILEHANDLE may be an expression whose value gives
> the
> name of the filehandle. The values for WHENCE are 0 to set
> the
> new position *in bytes* to POSITION, 1 to set it to the
> current
> position plus POSITION, and 2 to set it to EOF plus POSITION
> (typically negative). For WHENCE you may use the constants
> "SEEK_SET", "SEEK_CUR", and "SEEK_END" (start of the file,
> current position, end of the file) from the Fcntl module.
> Returns 1 upon success, 0 otherwise.
>
> Note the *in bytes*: even if the filehandle has been set to
> operate on characters (for example by using the ":utf8" open
> layer), tell() will return byte offsets, not character
> offsets
> (because implementing that would render seek() and tell()
> rather
> slow).
>
> If you want to position file for "sysread" or "syswrite",
> don't
> use "seek"--buffering makes its effect on the file's system
> position unpredictable and non-portable. Use "sysseek"
> instead.
>
> Due to the rules and rigors of ANSI C, on some systems you
> have
> to do a seek whenever you switch between reading and
> writing.
> Amongst other things, this may have the effect of calling
> stdio's clearerr(3). A WHENCE of 1 ("SEEK_CUR") is useful
> for
> not moving the file position:
>
> seek(TEST,0,1);
>
> This is also useful for applications emulating "tail -f".
> Once
> you hit EOF on your read, and then sleep for a while, you
> might
> have to stick in a seek() to reset things. The "seek"
> doesn't
> change the current position, but it *does* clear the end-of-
> file
> condition on the handle, so that the next "<FILE>" makes
> Perl
> try again to read something. We hope.
>
> If that doesn't work (some IO implementations are
> particularly
> cantankerous), then you may need something more like this:
>
> for (;;) {
> for ($curpos = tell(FILE); $_ = <FILE>;
> $curpos = tell(FILE)) {
> # search for some stuff and put it into files
> }
> sleep($for_a_while);
> seek(FILE, $curpos, 0);
> }
>
>
>
> 另外，您的code 我尝试了一下
> seek ($fp, 0, 0x80);
> print $fp "\x0";
> 实际的效果是 00000000h这一行 第1和2字节变成了0 没有偏移？
> 我自己尝试
> seek ($fp, 16*8, 0x00);
> print $fp "\x0";
> 可以达到目的
>
> 另外 我想请教 如何删除掉一部分内容呢 比如 0x90-0xb0
> 谢谢
> On 8月8日, 上午12时48分, Anthony WU <anthonywu...@gmail.com> wrote:
>
>> 以你所說的操作大約是
>> open (my $fp, '+<', 'x.dat');
>> binmode ($fp);
>> seek ($fp, 0, 0x80);
>> print $fp "\x0";
>> seek ($fp, 0, 0x82);
>> print $fp "\x0";
>> seek ($fp, 0, 0x84);
>> print $fp "\x0";
>> seek ($fp, 0, 0x86);
>> print $fp "\x8B";
>> seek ($fp, 0, 0x87);
>> print $fp "\x8B";
>> seek ($fp, 0, 0x88);
>> print $fp "\x0A";
>> seek ($fp, 0, 0x89);
>> print $fp "\x0A";
>> ....
>> ....
>> ....
>> close ($fp);
>>
>>
>>
>> -------- Original Message --------
>> Subject: [PerlChina] Re: 16进制文件操作
>> From: perlw01f <p3r1w...@gmail.com>
>> To: PerlChina Mongers 讨论组 <perlchina@googlegroups.com>
>> Date: 7/8/2009 21:16
>>
>>> 都是在确定的位置
>>>
>>> 如 00000080h 这一栏 第1 3 5 字节换为0 78换为8B 9 10 换为0A 还有一些其他的
>>>
>>> On 8月7日, 下午9时04分, Anthony WU <anthonywu...@gmail.com> wrote:
>>>
>>>> 你的字節是定位修改的嗎？有什麼規律的？
>>>>
>>>> -------- Original Message --------
>>>> Subject: [PerlChina] Re: 16进制文件操作
>>>> From: perlw01f <p3r1w...@gmail.com>
>>>> To: PerlChina Mongers 讨论组 <perlchina@googlegroups.com>
>>>> Date: 7/8/2009 20:56
>>>>
>>>>> 我有一个文件 x.dat，由x.rar.gz压缩而成 但是其中某些字节做了修改处理 现在的文件名是 a.dat
>>>>> 现在 我想逆行操作，即
>>>>> 先将a.date rename成x.rar.gz 然后利用ue修改某些字节 之后才能解压缩成x.date
>>>>>
>>>>> 由于文件数量较多 且ue 16进制 修改也不是很方便
>>>>> 所以想 用 perl实现
>>>>> 谢谢
>>>>>
>>>>> On 8月7日, 下午5时17分, cnhack TNT <cnhack...@gmail.com> wrote:
>>>>>
>>>>>> 能举例说明你要做的事情么？
>>>>>>
>>>>>> 2009/8/7 perlw01f <p3r1w...@gmail.com>
>>>>>>
>>>>>>> perl中 有没有类似ultredit中那种直接转换成16进制进行操作的方法或者module
>>>>>>>
>>>>>>> unpack是不是太费事了
>>>>>>>
>>>> --
>>>> Best Regards,
>>>> Anthony WU
>>>>
>> --
>> Best Regards,
>> Anthony WU
>>
> >
>
>
--
Best Regards,
Anthony WU
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