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revision 491 by ph10, Mon Mar 1 17:45:08 2010 UTC revision 579 by ph10, Wed Nov 24 17:39:25 2010 UTC
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1  MAINTENANCE README FOR PCRE  MAINTENANCE README FOR PCRE
2  ---------------------------  ===========================
3    
4  The files in the "maint" directory of the PCRE source contain data, scripts,  The files in the "maint" directory of the PCRE source contain data, scripts,
5  and programs that are used for the maintenance of PCRE, but which do not form  and programs that are used for the maintenance of PCRE, but which do not form
# Line 14  also contains some notes for maintainers Line 14  also contains some notes for maintainers
14    
15    
16  Files in the maint directory  Files in the maint directory
17  ----------------------------  ============================
18    
19  ----------------- This file is now OBSOLETE and no longer used ----------------  ---------------- This file is now OBSOLETE and no longer used ----------------
20  Builducptable    A Perl script that creates the contents of the ucptable.h file  Builducptable    A Perl script that creates the contents of the ucptable.h file
21                   from two Unicode data files, which themselves are downloaded                   from two Unicode data files, which themselves are downloaded
22                   from the Unicode web site. Run this script in the "maint"                   from the Unicode web site. Run this script in the "maint"
23                   directory.                   directory.
24  ----------------- This file is now OBSOLETE and no longer used ----------------  ---------------- This file is now OBSOLETE and no longer used ----------------
25    
26  GenerateUtt.py   A Python script to generate part of the pcre_tables.c file  GenerateUtt.py   A Python script to generate part of the pcre_tables.c file
27                   that contains Unicode script names in a long string with                   that contains Unicode script names in a long string with
28                   offsets, which is tedious to maintain by hand.                   offsets, which is tedious to maintain by hand.
29    
30  ManyConfigTests  A shell script that runs "configure, make, test" a number of  ManyConfigTests  A shell script that runs "configure, make, test" a number of
31                   times with different configuration settings.                   times with different configuration settings.
32    
33  MultiStage2.py   A Python script that generates the file pcre_ucd.c from three  MultiStage2.py   A Python script that generates the file pcre_ucd.c from three
34                   Unicode data tables, which are themselves downloaded from the                   Unicode data tables, which are themselves downloaded from the
35                   Unicode web site. Run this script in the "maint" directory.                   Unicode web site. Run this script in the "maint" directory.
36                   The generated file contains the tables for a 2-stage lookup                   The generated file contains the tables for a 2-stage lookup
37                   of Unicode properties.                   of Unicode properties.
38    
39    pcre_chartables.c.non-standard
40                     This is a set of character tables that came from a Windows
41                     system. It has characters greater than 128 that are set as
42                     spaces, amongst other things. I kept it so that it can be
43                     used for testing from time to time.
44    
45  README           This file.  README           This file.
46    
47  Unicode.tables   The files in this directory, DerivedGeneralCategory.txt,  Unicode.tables   The files in this directory, DerivedGeneralCategory.txt,
48                   Scripts.txt and UnicodeData.txt, were downloaded from the                   Scripts.txt and UnicodeData.txt, were downloaded from the
49                   Unicode web site. They contain information about Unicode                   Unicode web site. They contain information about Unicode
50                   characters and scripts.                   characters and scripts.
# Line 61  utf8.c           A short, freestanding C Line 67  utf8.c           A short, freestanding C
67    
68    
69  Updating to a new Unicode release  Updating to a new Unicode release
70  ---------------------------------  =================================
71    
72  When there is a new release of Unicode, the files in Unicode.tables must be  When there is a new release of Unicode, the files in Unicode.tables must be
73  refreshed from the web site. If the new version of Unicode adds new character  refreshed from the web site. If the new version of Unicode adds new character
# Line 71  can be run to generate a new version of Line 77  can be run to generate a new version of
77  run to generate the tricky tables for inclusion in pcre_tables.c.  run to generate the tricky tables for inclusion in pcre_tables.c.
78    
79  If MultiStage2.py gives the error "ValueError: list.index(x): x not in list",  If MultiStage2.py gives the error "ValueError: list.index(x): x not in list",
80  the cause is usually a missing (or misspelt) name in the list of scripts. I  the cause is usually a missing (or misspelt) name in the list of scripts. I
81  couldn't find a straightforward list of scripts on the Unicode site, but  couldn't find a straightforward list of scripts on the Unicode site, but
82  there's a useful Wikipedia page that list them, and notes the Unicode version  there's a useful Wikipedia page that list them, and notes the Unicode version
83  in which they were introduced:  in which they were introduced:
84    
85  http://en.wikipedia.org/wiki/Unicode_scripts#Table_of_Unicode_scripts  http://en.wikipedia.org/wiki/Unicode_scripts#Table_of_Unicode_scripts
# Line 83  pcre_ucd.c work properly, using the data Line 89  pcre_ucd.c work properly, using the data
89  of test characters. The source file ucptest.c must be updated whenever new  of test characters. The source file ucptest.c must be updated whenever new
90  Unicode script names are added.  Unicode script names are added.
91    
92  Note also that both the pcresyntax.3 and pcrepattern.3 man pages contain lists  Note also that both the pcresyntax.3 and pcrepattern.3 man pages contain lists
93  of Unicode script names.  of Unicode script names.
94    
95    
96  Preparing for a PCRE release  Preparing for a PCRE release
97  ----------------------------  ============================
98    
99  This section contains a checklist of things that I consult before building a  This section contains a checklist of things that I consult before building a
100  distribution for a new release.  distribution for a new release.
101    
102  . Ensure that the version number and version date are correct in configure.ac.  . Ensure that the version number and version date are correct in configure.ac.
103    
104  . If new build options have been added, ensure that they are added to the CMake  . If new build options have been added, ensure that they are added to the CMake
105    files as well as to the autoconf files.    files as well as to the autoconf files.
106    
107  . Run ./autogen.sh to ensure everything is up-to-date.  . Run ./autogen.sh to ensure everything is up-to-date.
108    
109  . Compile and test with many different config options, and combinations of  . Compile and test with many different config options, and combinations of
110    options. The maint/ManyConfigTests script now encapsulates this testing.    options. The maint/ManyConfigTests script now encapsulates this testing.
111    
112  . Run perltest.pl on the test data for tests 1, 4, 6, and 11. The first two can  . Run perltest.pl on the test data for tests 1, 4, 6, and 11. The output should
113    be run with Perl 5.8 or 5.10; the last two require Perl 5.10. The output    match the PCRE test output, apart from the version identification at the
114    should match the PCRE test output, apart from the version identification at    start of each test. The other tests are not Perl-compatible (they use various
115    the start of each test. The other tests are not Perl-compatible (they use    PCRE-specific features or options).
   various PCRE-specific features or options).  
116    
117  . Test with valgrind by running "RunTest valgrind". There is also "RunGrepTest  . Test with valgrind by running "RunTest valgrind". There is also "RunGrepTest
118    valgrind", though that takes quite a long time.    valgrind", though that takes quite a long time.
119    
 . It may also useful to test with Electric Fence, though the fact that it  
   grumbles for missing free() calls can be a nuisance. (A missing free() in  
   pcretest is hardly a big problem.) To build with EF, use:  
   
     LIBS='/usr/lib/libefence.a -lpthread' with ./configure.  
   
   Then all normal runs use it to check for buffer overflow. Also run everything  
   with:  
   
     EF_PROTECT_BELOW=1 <whatever>  
   
   because there have been problems with lookbehinds that looked too far.  
   
120  . Test with the emulated memmove() function by undefining HAVE_MEMMOVE and  . Test with the emulated memmove() function by undefining HAVE_MEMMOVE and
121    HAVE_BCOPY in config.h. You may see a number of "pcre_memmove defined but not    HAVE_BCOPY in config.h. You may see a number of "pcre_memmove defined but not
122    used" warnings for the modules in which there is no call to memmove(). These    used" warnings for the modules in which there is no call to memmove(). These
123    can be ignored.    can be ignored.
124    
125  . Documentation: check AUTHORS, COPYING, ChangeLog (check version and date),  . Documentation: check AUTHORS, COPYING, ChangeLog (check version and date),
126    INSTALL, LICENCE, NEWS (check version and date), NON-UNIX-USE, and README.    INSTALL, LICENCE, NEWS (check version and date), NON-UNIX-USE, and README.
127    Many of these won't need changing, but over the long term things do change.    Many of these won't need changing, but over the long term things do change.
128    
129  . Man pages: Check all man pages for \ not followed by e or f or " because  . Man pages: Check all man pages for \ not followed by e or f or " because
130    that indicates a markup error.    that indicates a markup error. However, there is one exception: pcredemo.3,
131      which is created from the pcredemo.c program. It contains three instances
132      of \\n.
133    
134  . When the release is built, test it on a number of different operating  . When the release is built, test it on a number of different operating
135    systems if possible, and using different compilers as well. For example,    systems if possible, and using different compilers as well. For example,
# Line 145  distribution for a new release. Line 139  distribution for a new release.
139    
140    
141  Making a PCRE release  Making a PCRE release
142  ---------------------  =====================
143    
144  Run PrepareRelease and commit the files that it changes (by removing trailing  Run PrepareRelease and commit the files that it changes (by removing trailing
145  spaces). Then run "make distcheck" to create the tarballs and the zipball.  spaces). Then run "make distcheck" to create the tarballs and the zipball.
146  Double-check with "svn status", then create an SVN tagged copy:  Double-check with "svn status", then create an SVN tagged copy:
147    
148    svn copy svn://vcs.exim.org/pcre/code/trunk \    svn copy svn://vcs.exim.org/pcre/code/trunk \
149             svn://vcs.exim.org/pcre/code/tags/pcre-8.xx             svn://vcs.exim.org/pcre/code/tags/pcre-8.xx
150    
151  Don't forget to update Freshmeat when the new release is out, and to tell  Don't forget to update Freshmeat when the new release is out, and to tell
152  webmaster@pcre.org and the mailing list.  webmaster@pcre.org and the mailing list. Also, update the list of version
153    numbers in Bugzilla (edit products).
154    
155    
156  Future ideas (wish list)  Future ideas (wish list)
157  ------------------------  ========================
158    
159  This section records a list of ideas so that they do not get forgotten. They  This section records a list of ideas so that they do not get forgotten. They
160  vary enormously in their usefulness and potential for implementation. Some are  vary enormously in their usefulness and potential for implementation. Some are
# Line 183  others are relatively new. Line 178  others are relatively new.
178      over the existing "required byte" (reqbyte) feature that just remembers one      over the existing "required byte" (reqbyte) feature that just remembers one
179      byte.      byte.
180    
181    * These probably need to go in study():    * These probably need to go in pcre_study():
182    
183      o Remember an initial string rather than just 1 char?      o Remember an initial string rather than just 1 char?
184    
# Line 191  others are relatively new. Line 186  others are relatively new.
186        earlier one if common to all alternatives.        earlier one if common to all alternatives.
187    
188      o Friedl contains other ideas.      o Friedl contains other ideas.
189    
190      * pcre_study() does not set initial byte flags for Unicode property types
191        such as \p; I don't know how much benefit there would be for, for example,
192        setting the bits for 0-9 and all bytes >= xC0 when a pattern starts with
193        \p{N}.
194    
195      * There is scope for more "auto-possessifying" in connection with \p and \P.
196    
197  . If Perl gets to a consistent state over the settings of capturing sub-  . If Perl gets to a consistent state over the settings of capturing sub-
198    patterns inside repeats, see if we can match it. One example of the    patterns inside repeats, see if we can match it. One example of the
199    difference is the matching of /(main(O)?)+/ against mainOmain, where PCRE    difference is the matching of /(main(O)?)+/ against mainOmain, where PCRE
# Line 202  others are relatively new. Line 204  others are relatively new.
204    
205  . Unicode  . Unicode
206    
   * Note that in Perl, \s matches \pZ and similarly for \d, \w and the POSIX  
     character classes. For the moment, I've chosen not to support this for  
     backward compatibility, for speed, and because it would be messy to  
     implement.  
   
207    * A different approach to Unicode might be to use a typedef to do everything    * A different approach to Unicode might be to use a typedef to do everything
208      in unsigned shorts instead of unsigned chars. Actually, we'd have to have a      in unsigned shorts instead of unsigned chars. Actually, we'd have to have a
209      new typedef to distinguish data from bits of compiled pattern that are in      new typedef to distinguish data from bits of compiled pattern that are in
# Line 268  others are relatively new. Line 265  others are relatively new.
265    
266  . Someone suggested --disable-callout to save code space when callouts are  . Someone suggested --disable-callout to save code space when callouts are
267    never wanted. This seems rather marginal.    never wanted. This seems rather marginal.
268    
269  . Check names that consist entirely of digits: PCRE allows, but do Perl and  . Check names that consist entirely of digits: PCRE allows, but do Perl and
270    Python, etc?    Python, etc?
271    
272  . A user suggested a parameter to limit the length of string matched, for  . A user suggested a parameter to limit the length of string matched, for
273    example if the parameter is N, the current match should fail if the matched    example if the parameter is N, the current match should fail if the matched
274    substring exceeds N. This could apply to both match functions. The value    substring exceeds N. This could apply to both match functions. The value
275    could be a new field in the extra block.    could be a new field in the extra block.
276    
277  . Callouts with arguments: (?Cn:ARG) for instance.  . Callouts with arguments: (?Cn:ARG) for instance.
278    
279  . A user is going to supply a patch to generalize the API for user-specific  . A user is going to supply a patch to generalize the API for user-specific
280    memory allocation so that it is more flexible in threaded environments. Thiw    memory allocation so that it is more flexible in threaded environments. This
281    was promised a long time ago, and never appeared...    was promised a long time ago, and never appeared...
282    
283  . Write a function that generates random matching strings for a compiled regex.  . Write a function that generates random matching strings for a compiled regex.
284    
285  . Write a wrapper to maintain a structure with specified runtime parameters,  . Write a wrapper to maintain a structure with specified runtime parameters,
286    such as recurse limit, and pass these to PCRE each time it is called. Also    such as recurse limit, and pass these to PCRE each time it is called. Also
287    maybe malloc and free. A user sent a prototype.    maybe malloc and free. A user sent a prototype.
288    
289  . Pcregrep: an option to specify the output line separator, either as a string  . Pcregrep: an option to specify the output line separator, either as a string
290    or select from a fixed list. This is not dead easy, because at the moment it    or select from a fixed list. This is not dead easy, because at the moment it
291    outputs whatever is in the input file.    outputs whatever is in the input file.
292    
293  . Improve the code for duplicate checking in pcre_dfa_exec(). An incomplete,  . Improve the code for duplicate checking in pcre_dfa_exec(). An incomplete,
294    non-thread-safe patch showed that this can help performance for patterns    non-thread-safe patch showed that this can help performance for patterns
295    where there are many alternatives. However, a simple thread-safe    where there are many alternatives. However, a simple thread-safe
296    implementation that I tried made things worse in many simple cases, so this    implementation that I tried made things worse in many simple cases, so this
297    is not an obviously good thing.    is not an obviously good thing.
298    
299  . Make the longest lookbehind available via pcre_fullinfo(). This is not  . Make the longest lookbehind available via pcre_fullinfo(). This is not
300    straightforward because lookbehinds can be nested inside lookbehinds. This    straightforward because lookbehinds can be nested inside lookbehinds. This
301    case will have to be identified, and the amounts added. This should then give    case will have to be identified, and the amounts added. This should then give
302    the maximum possible lookbehind length. The reason for wanting this is to    the maximum possible lookbehind length. The reason for wanting this is to
303    help when implementing multi-segment matching using pcre_exec() with partial    help when implementing multi-segment matching using pcre_exec() with partial
304    matching and overlapping segments.    matching and overlapping segments.
305    
306  . PCRE cannot at present distinguish between subpatterns with different names,  . PCRE cannot at present distinguish between subpatterns with different names,
307    but the same number (created by the use of ?|). In order to do so, a way of    but the same number (created by the use of ?|). In order to do so, a way of
308    remembering *which* subpattern numbered n matched is needed. Bugzilla #760.    remembering *which* subpattern numbered n matched is needed. Bugzilla #760.
309      Now that (*MARK) has been implemented, it can perhaps be used as a way round
310      this problem.
311    
312    . Instead of having #ifdef HAVE_CONFIG_H in each module, put #include
313      "something" and the the #ifdef appears only in one place, in "something".
314    
315  Philip Hazel  Philip Hazel
316  Email local part: ph10  Email local part: ph10
317  Email domain: cam.ac.uk  Email domain: cam.ac.uk
318  Last updated: 26 September 2009  Last updated: 24 November 2010

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