[PEAR-BUG] Req #6411 [Com]: Various fixes to regexes

Edit report at http://pear.php.net/bugs/bug.php?id=6411&edit=1

 ID:               6411
 Comment by:       [email protected]
 Reported By:      alan at akbkhome dot com
 Summary:          Various fixes to regexes
 Status:           Open
 Type:             Feature/Change Request
 Package:          File_Gettext
 Operating System: all
 PHP Version:      Irrelevant
 Roadmap Versions: 
 New Comment:

However, the pattern you suggest will now fail for an escaped backslash
followed by an escaped quote due to the negative look-behind
So, something like this will not match:
msgid "AAA"
"BBB\\\"CCC"

I don't think using a regex-based parser here is a good choice, because
there is a lot more to the PO format than the mere msgid & msgstr and
taking all of that into account using regular expressions may prove
quite difficult.
See also
http://download.oracle.com/docs/cd/E19683-01/817-0659/6mgeo5s1u/index.html
that lists other possible directives and has information about the
meaning of special comments too.


Previous Comments:
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[2006-01-08 03:48:21] ivanwyc at gmail dot com

http://www.ivanwong.info/pear/File_Gettext.patch

Thanks.

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[2006-01-07 04:48:28] mike

Please make the patch available online.

Thanks a lot.

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[2006-01-06 04:39:45] ivanwyc at gmail dot com

To give more details for this bug:

- the original regex for msgid and msgstr doesn't really work for things
like this:

msgid "AAA"
"BBB\"CCC"

as the '\' of '\"' always take the first of the alternation
([^"]|\\\\"), the second term has no effect.

- Swapping the alternation (\\\\"|[^"]) should work theoretically, but
practically it segfaults for long text, refer to [1]. Also the regex we
propose is the fastest as suggested in [1].

- prepare() didn't escape the \ character as well:

[1] http://www.gossamer-threads.com/lists/perl/porters/199811

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[2006-01-04 01:49:42] alan_k

Description:
------------
diff -pur File/Gettext/PO.php File.new/Gettext/PO.php
--- File/Gettext/PO.php	2005-12-30 16:36:45.000000000 +0800
+++ File.new/Gettext/PO.php	2005-12-30 16:35:35.000000000 +0800
@@ -64,8 +64,8 @@ class File_Gettext_PO extends File_Gette
         
         // match all msgid/msgstr entries
         $matched = preg_match_all(
-            '/(msgid\s+("([^"]|\\\\")*?"\s*)+)\s+' .
-            '(msgstr\s+("([^"]|\\\\")*?"\s*)+)/',
+            '/msgid\s+((?:".*(?<!\\\\)"\s*)+)\s+' .
+            'msgstr\s+((?:".*(?<!\\\\)"\s*)+)/',
             $contents, $matches
         );
         unset($contents);
@@ -76,10 +76,8 @@ class File_Gettext_PO extends File_Gette
         
         // get all msgids and msgtrs
         for ($i = 0; $i < $matched; $i++) {
-            $msgid = preg_replace(
-                '/\s*msgid\s*"(.*)"\s*/s', '\\1', $matches[1][$i]);
-            $msgstr= preg_replace(
-                '/\s*msgstr\s*"(.*)"\s*/s', '\\1', $matches[4][$i]);
+            $msgid = substr(trim($matches[1][$i]), 1, -1);
+            $msgstr = substr(trim($matches[2][$i]), 1, -1);
             $this->strings[parent::prepare($msgid)] =
parent::prepare($msgstr);
         }
         
diff -pur File/Gettext.php File.new/Gettext.php
--- File/Gettext.php	2005-12-30 16:36:45.000000000 +0800
+++ File.new/Gettext.php	2005-12-30 16:35:41.000000000 +0800
@@ -131,12 +131,12 @@ class File_Gettext
     function prepare($string, $reverse = false)
     {
         if ($reverse) {
-            $smap = array('"', "\n", "\t", "\r");
-            $rmap = array('\\"', '\\n"' . "\n" . '"', '\\t', '\\r');
+            $smap = array('\\', '"', "\n", "\t", "\r");
+            $rmap = array('\\\\', '\\"', '\\n"' . "\n" . '"', '\\t',
'\\r');
             return (string) str_replace($smap, $rmap, $string);
         } else {
-            $smap = array('/"\s+"/', '/\\\\n/', '/\\\\r/', '/\\\\t/',
'/\\\\"/');
-            $rmap = array('', "\n", "\r", "\t", '"');
+            $smap = array('/"\s+"/', '/\\\\n/', '/\\\\r/', '/\\\\t/',
'/\\\\"/', '/\\\\\\\\/');
+            $rmap = array('', "\n", "\r", "\t", '"', '\\');
             return (string) preg_replace($smap, $rmap, $string);
         }
     }

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Edit this bug report at http://pear.php.net/bugs/bug.php?id=6411&edit=1