[Raleigh-talk] [Perl help] - Multiple substitutions in a file

Tue Feb 22 23:23:19 PST 2011

Ooh, shiny!  Nicely done.

On Wed, Feb 23, 2011 at 2:05 AM, Mike South <msouth at gmail.com> wrote:

> If you have the whole file in a string and the replacements in an array and
> the 'marker' doesn't change, I think the following will work.
>
> The /e modifier executes code, so s/foo/ do something here /eg will replace
> each instance of foo with whatever 'do something here', executed as perl
> code, returns.  So I just made it grab the next color off the list and put
> that in place.
>
> In case you have more of the 'markers' than you have replacements, I just
> put $1 back in right where we found it.  The stuff that's printing out the
> length of the string is a rough check to make sure I'm not accidentally
> clobbering part of the string.
>
> mike
>
>
> use strict;
> use warnings;
>
> my $file = '
> 08 00 00 00 FF FF FF FF FF FF FF FF 1B 00 00 00 02 01 10 00 28 01 00 00 09
> 00 00 00 FF FF FF FF FF FF FF FF 1C 00 00 00 14 00 14 00 0D 00 00 00 00 00
> 0D 00 18 00 00 00 11 00 00 00 FF FF FF FF 08 00 00 05 02 0E 00 00 18 00 00
> 00 0E 00 00 00 FF FF FF FF 08 00 00 1C 00 00 00 FF 18 00 00 00 09 00 00 00
> FF FF FF FF 08 00 00 11 10 00 00 00 18 00 00 00 0F 00 00 00 FF FF FF FF 08
> 00 00 01 11 02 02 01 18 00 00 00 03 00 00 00 08 00 00 1C FF FF FF FF 08 00
> 00 01 05 00 08 01 18 00 00 00 10 00 00 00 FF FF FF FF 08 00 00 05 01 0F 00
> 00 18 00 00 00 05 00 08 00 00 1C 00 00 FF FF FF FF 08 00 00 05 01 0F 00 08
> 00 00 1C 00 18 00 00 ';
>
> my $length = length $file;
>
> my $color1 = '11#AA#BB#CC';
> my $color2 = '22#DD#EE#FF';
> my $color3 = '33#XX#XX#XX';
> my @replacements = ($color1, $color2, $color3);
> #my @replacements = ($color1, $color2);
>
> my $marker = '08 00 00 1C ';
> my $xx = qr/[[:xdigit:]]{2}/; # two hex digits
> $file =~ s/$marker(($xx ){3}$xx)/$marker . (shift(@replacements) || $1)/ge;
>
>
> print $file,$/;
> print "length was $length, now it's ", length($file), $/;
>
>
> On Tue, Feb 22, 2011 at 11:49 PM, Mike South <msouth at gmail.com> wrote:
>
>> Also those \d's aren't going to match A-F are they?
>>
>> Are you familiar with qr// to let you store a regex bit in a variable?
>>  That might make some of this more readable.
>>
>> mike
>>
>> On Tue, Feb 22, 2011 at 10:58 PM, Matt Nash <mattnashbrowns at gmail.com>wrote:
>>
>>> Of course, you want actual spaces (not '\s') in the replace string, but
>>> you knew that.
>>>
>>>
>>> On Tue, Feb 22, 2011 at 9:56 PM, Matt Nash <mattnashbrowns at gmail.com>wrote:
>>>
>>>> Hi John,
>>>>
>>>> You are reading the entire file into an array of lines, then processing
>>>> that array using a C-style for loop and interpolating the index var into the
>>>> search string... and that is the LEAST crazy thing. :)  It works, of course,
>>>> because it turns out that there are infinitely many ways to do it.
>>>>
>>>> For your immediate problem of the search-and-replace, I recommend
>>>> reading the  whole file into a single string, newlines and all, then using
>>>> the /gc modifiers in the regex.  Maybe put your colorChange stuff into an
>>>> array that you loop through, checking the regex for the nth match:
>>>>
>>>> @changes = ($change1, $change2, $change3);
>>>>
>>>> foreach $change (@changes) {
>>>>     $wholefile =~
>>>> s|08\s00\s00\s1C\s\d\d\s\d\d\s\d\d\s\d\d|08\s00\s00\s1C\s$change|gc;
>>>> }
>>>>
>>>> see http://perldoc.perl.org/perlre.html and
>>>> http://perldoc.perl.org/perlretut.htm<http://perldoc.perl.org/perlretut.html#Using-regular-expressions-in-Perl> for
>>>> lots of details, but the upshot of the modifiers is: g makes it keep looking
>>>> for matches; c tells it to remember where it last matched, and start from
>>>> there on the next match.  You don't have to care what n is, because you are
>>>> matching your search string exactly as many times as you have changes to
>>>> make.
>>>>
>>>> ...but this project sounds ripe for refactoring, if I may be so bold.
>>>>  Could it be that what you really need is a templating system?
>>>>
>>>> Thanks for bringing some much-needed questions to this list!
>>>>
>>>> Matt
>>>>
>>>> On Tue, Feb 22, 2011 at 8:31 PM, John Ricker <sephtin+pm-talk at gmail.com
>>>> > wrote:
>>>>
>>>>> Received so much help with the last question (which seems to be
>>>>> functioning great, btw.. thanks all)... thought I'd try again.  ;)
>>>>>
>>>>> Have a script that was recently migrated to Perl from shell/bash, and
>>>>> am wondering if there's an easy way in Perl to do the following-
>>>>>
>>>>> File(s) being modified are hex, and look something like:
>>>>> ---x---
>>>>> ...
>>>>> 08 00 00 00 FF FF FF FF FF FF FF FF 1B 00 00 00 02 01 10 00 28 01 00 00
>>>>> 09 00 00 00 FF FF FF FF FF FF FF FF 1C 00 00 00 14 00 14 00 0D 00 00 00 00
>>>>> 00 0D 00 18 00 00 00 11 00 00 00 FF FF FF FF 08 00 00 05 02 0E 00 00 18 00
>>>>> 00 00 0E 00 00 00 FF FF FF FF 08 00 00 1C 00 00 00 FF 18 00 00 00 09 00 00
>>>>> 00 FF FF FF FF 08 00 00 11 10 00 00 00 18 00 00 00 0F 00 00 00 FF FF FF FF
>>>>> 08 00 00 01 11 02 02 01 18 00 00 00 03 00 00 00 FF FF FF FF 08 00 00 01 05
>>>>> 00 08 01 18 00 00 00 10 00 00 00 FF FF FF FF 08 00 00 05 01 0F 00 00 18 00
>>>>> 00 00 05 00 00 00 FF FF FF FF 08 00 00 05 01 0F 00 00 18 00 00
>>>>> ...
>>>>> ---x---
>>>>> File(s) contain several occurrences of "08 00 00 1c ## ## ## ##" or
>>>>> more appropriately for this list: "08\s00\s00\s1C\s\d\d\s\d\d\s\d\d\s\d\d"
>>>>>
>>>>>  Now on to the good stuff...  I would like to replace the ## ## ## ##
>>>>> with my chosen colors, that are being provided by vars... Example:
>>>>> colorChange1="FF 00 00 FF"
>>>>> colorChange2="FF FF 00 FF"
>>>>> colorChange3="FF 00 FF FF"
>>>>> ...
>>>>>
>>>>> I'm wondering how it might be possible, to replace the FIRST occurrence
>>>>> (in the file, NOT in a line) of "08 00 00 1C ## ## ## ##" with "08 00 00 1C
>>>>> $colorChange1", the second with "08 00 00 1C $colorChange2", etc.
>>>>>
>>>>> More info:
>>>>> --Script modifies files to theme them, in this case, I'm taking a
>>>>> BINARY (compiled XML) file, converting it to HEX via xxd, and then changing
>>>>> the text color for a theme via substitution.
>>>>> --I originally thought it could be done similar to what sed does...
>>>>> with s|(08\s00\s00\s1C)\s\d\d\s\d\d\s\d\d\s\d\d|$1$colorChange1|1  (note
>>>>> last digit...), but testing has shown that this doesn't work as expected.
>>>>> --Not really related, but in the binary, the colors are actually
>>>>> backwards, so color - FF AB CD EF becomes binary - EF CD AB FF, but that's
>>>>> an easy change.
>>>>> --CURRENTLY in my script, I'm doing this via a sub, passing an array of
>>>>> the colors, the file, and the file location (directory), and pulling the
>>>>> file, making the changes, and saving it back out via loop... BUT, because I
>>>>> couldn't figure out how to just do the multiple replaces... I cheated and
>>>>> made template files that contain "08 00 00 1C 11 11 11 11" and "08 00 00 1C
>>>>> 22 22 22 22", so when I iterate through the loop, I just change like so:
>>>>> for ( $i = 1 ; $i <= $COUNT ; $i++ ) {
>>>>> ...
>>>>>     $line =~ s|08\s00\s00\s1c\s$i$i\s$i$i\s$i$i\s$i$i\s|08 00 00 1c
>>>>> $array_ref[$i]|;
>>>>> ...
>>>>> }
>>>>>
>>>>> Code works, but I'd much rather be able to pull native files straight
>>>>> out of the .zip, and change them that way... :P
>>>>>
>>>>> Anyway, again, if there are specifics I missed, happy to provide them.
>>>>>
>>>>> I keep thinking there should be an easy way to do this... but my
>>>>> google-fu is failing me..
>>>>>
>>>>> Thanks again for the help with the previous problem, and in advance for
>>>>> any assistance on this one.  :)
>>>>> At the very least, I guess I can provide some chatter to the group.
>>>>>
>>>>> -John (sephtin @gmail)
>>>>>
>>>>> _______________________________________________
>>>>> Raleigh-talk mailing list
>>>>> Raleigh-talk at pm.org
>>>>> http://mail.pm.org/mailman/listinfo/raleigh-talk
>>>>>
>>>>>
>>>>
>>>
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>>>
>>>
>>
>
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