[PerlChina] Re: 16进制文件操作

tell Returns the current position *in bytes* for FILEHANDLE
非常感谢

On 8月9日, 上午2时20分, Anthony WU <anthonywu...@gmail.com> wrote:
> my $tmp;
> open (my $fp, '+<', 'filename');
> binmode ($fp);
> read ($fp, $tmp, 0x8f);
> .................
> seek ($fp, 0xb0, 0);
> read ($fp, $tmp, (-s $fp) - tell ($fp));
> .................
> 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: 8/8/2009 23:51
> > 接问一句 如何 读取 0x00-0x8f ？
> > 我先 binmode 再 read 貌似不好使？
>
> >> On 8月8日, 下午7时24分, Anthony WU <anthonywu...@gmail.com> wrote:> 我把 seek 第二 及第三個參數寫反了，刪除是不能的，但你可以通過 先讀
>
> >>> 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 <p3r1w...@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
>
> --
> Best Regards,
> Anthony WU
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