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revision 491 by ph10, Mon Mar 1 17:45:08 2010 UTC revision 733 by ph10, Tue Oct 11 10:29:36 2011 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. The relevant files are CMakeLists.txt
106      and config-cmake.h.in. After making a release tarball, test it out with CMake
107      if there have been changes here.
108    
109  . Run ./autogen.sh to ensure everything is up-to-date.  . Run ./autogen.sh to ensure everything is up-to-date.
110    
111  . Compile and test with many different config options, and combinations of  . Compile and test with many different config options, and combinations of
112    options. The maint/ManyConfigTests script now encapsulates this testing.    options. Also, test with valgrind by running "RunTest valgrind" and
113      "RunGrepTest valgrind" (which takes quite a long time). The script
114      maint/ManyConfigTests now encapsulates this testing. It runs tests with
115      different configurations, and it also runs some of them with valgrind, all of
116      which can take quite some time.
117    
118  . 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, 11, and 12. The output
   be run with Perl 5.8 or 5.10; the last two require Perl 5.10. The output  
119    should match the PCRE test output, apart from the version identification at    should match the PCRE test output, apart from the version identification at
120    the start of each test. The other tests are not Perl-compatible (they use    the start of each test. The other tests are not Perl-compatible (they use
121    various PCRE-specific features or options).    various PCRE-specific features or options).
122    
123  . Test with valgrind by running "RunTest valgrind". There is also "RunGrepTest  . It is possible to test with the emulated memmove() function by undefining
124    valgrind", though that takes quite a long time.    HAVE_MEMMOVE and HAVE_BCOPY in config.h, though I do not do this often. You
125      may see a number of "pcre_memmove defined but not used" warnings for the
126  . It may also useful to test with Electric Fence, though the fact that it    modules in which there is no call to memmove(). These can be ignored.
   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>  
127    
128    because there have been problems with lookbehinds that looked too far.  . Documentation: check AUTHORS, COPYING, ChangeLog (check version and date),
   
 . Test with the emulated memmove() function by undefining HAVE_MEMMOVE and  
   HAVE_BCOPY in config.h. You may see a number of "pcre_memmove defined but not  
   used" warnings for the modules in which there is no call to memmove(). These  
   can be ignored.  
   
 . Documentation: check AUTHORS, COPYING, ChangeLog (check version and date),  
129    INSTALL, LICENCE, NEWS (check version and date), NON-UNIX-USE, and README.    INSTALL, LICENCE, NEWS (check version and date), NON-UNIX-USE, and README.
130    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.
131    
132  . Man pages: Check all man pages for \ not followed by e or f or " because  . I used to test new releases myself on a number of different operating
133    that indicates a markup error.    systems, using different compilers as well. For example, on Solaris it is
134      helpful to test using Sun's cc compiler as a change from gcc. Adding
135  . When the release is built, test it on a number of different operating    -xarch=v9 to the cc options does a 64-bit test, but it also needs -S 64 for
136    systems if possible, and using different compilers as well. For example,    pcretest to increase the stack size for test 2. Since I retired I can no
137    on Solaris it is helpful to test using Sun's cc compiler as a change from    longer do this, but instead I rely on putting out release candidates for
138    gcc. Adding -xarch=v9 to the cc options does a 64-bit test, but it also    folks on the pcre-dev list to test.
   needs -S 64 for pcretest to increase the stack size for test 2.  
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). The first thing this script does is to run CheckMan on the man pages;
146  Double-check with "svn status", then create an SVN tagged copy:  if it finds any markup errors, it reports them and then aborts.
147    
148    Once PrepareRelease has run clean, run "make distcheck" to create the tarballs
149    and the zipball. Double-check with "svn status", then create an SVN tagged
150    copy:
151    
152    svn copy svn://vcs.exim.org/pcre/code/trunk \    svn copy svn://vcs.exim.org/pcre/code/trunk \
153             svn://vcs.exim.org/pcre/code/tags/pcre-8.xx             svn://vcs.exim.org/pcre/code/tags/pcre-8.xx
154    
155  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
156  webmaster@pcre.org and the mailing list.  webmaster@pcre.org and the mailing list. Also, update the list of version
157    numbers in Bugzilla (edit products).
158    
159    
160  Future ideas (wish list)  Future ideas (wish list)
161  ------------------------  ========================
162    
163  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
164  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 182  others are relatively new.
182      over the existing "required byte" (reqbyte) feature that just remembers one      over the existing "required byte" (reqbyte) feature that just remembers one
183      byte.      byte.
184    
185    * These probably need to go in study():    * These probably need to go in pcre_study():
186    
187      o Remember an initial string rather than just 1 char?      o Remember an initial string rather than just 1 char?
188    
# Line 191  others are relatively new. Line 190  others are relatively new.
190        earlier one if common to all alternatives.        earlier one if common to all alternatives.
191    
192      o Friedl contains other ideas.      o Friedl contains other ideas.
193    
194      * pcre_study() does not set initial byte flags for Unicode property types
195        such as \p; I don't know how much benefit there would be for, for example,
196        setting the bits for 0-9 and all bytes >= xC0 when a pattern starts with
197        \p{N}.
198    
199      * There is scope for more "auto-possessifying" in connection with \p and \P.
200    
201  . 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-
202    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
203    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 208  others are relatively new.
208    
209  . Unicode  . Unicode
210    
211    * Note that in Perl, \s matches \pZ and similarly for \d, \w and the POSIX    * There has been a request for direct support of 16-bit characters and
212      character classes. For the moment, I've chosen not to support this for      UTF-16 (Bugzilla #1049). However, since Unicode is moving beyond purely
213      backward compatibility, for speed, and because it would be messy to      16-bit characters, is this worth it at all? One possible way of handling
214      implement.      16-bit characters would be to "load" them in the same way that UTF-8
215        characters are loaded. Another possibility is to provide a set of
216        translation functions, and build an index during translation so that the
217        returned offsets can automatically be translated (using the index) after a
218        match.
219    
220    * 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
221      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
222      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
223      bytes, I think. There would need to be conversion functions in and out. I      bytes, I think. There would need to be conversion functions in and out. I
224      don't think this is particularly trivial - and anyway, Unicode now has      don't think this is particularly trivial - and anyway, Unicode now has
225      characters that need more than 16 bits, so is this at all sensible?      characters that need more than 16 bits, so is this at all sensible? I
226        suspect not.
   * There has been a request for direct support of 16-bit characters and  
     UTF-16. However, since Unicode is moving beyond purely 16-bit characters,  
     is this worth it at all? One possible way of handling 16-bit characters  
     would be to "load" them in the same way that UTF-8 characters are loaded.  
227    
228  . Allow errorptr and erroroffset to be NULL. I don't like this idea.  . Allow errorptr and erroroffset to be NULL. I don't like this idea.
229    
# Line 268  others are relatively new. Line 274  others are relatively new.
274    
275  . Someone suggested --disable-callout to save code space when callouts are  . Someone suggested --disable-callout to save code space when callouts are
276    never wanted. This seems rather marginal.    never wanted. This seems rather marginal.
277    
278  . 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
279    Python, etc?    Python, etc?
280    
281  . 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
282    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
283    substring exceeds N. This could apply to both match functions. The value    substring exceeds N. This could apply to both match functions. The value
284    could be a new field in the extra block.    could be a new field in the extra block.
285    
286  . Callouts with arguments: (?Cn:ARG) for instance.  . Callouts with arguments: (?Cn:ARG) for instance.
287    
288  . 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
289    memory allocation so that it is more flexible in threaded environments. Thiw    memory allocation so that it is more flexible in threaded environments. This
290    was promised a long time ago, and never appeared...    was promised a long time ago, and never appeared...
291    
292  . Write a function that generates random matching strings for a compiled regex.  . Write a function that generates random matching strings for a compiled regex.
293    
294  . Write a wrapper to maintain a structure with specified runtime parameters,  . Write a wrapper to maintain a structure with specified runtime parameters,
295    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
296    maybe malloc and free. A user sent a prototype.    maybe malloc and free. A user sent a prototype.
297    
298  . 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
299    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
300    outputs whatever is in the input file.    outputs whatever is in the input file.
301    
302  . Improve the code for duplicate checking in pcre_dfa_exec(). An incomplete,  . Improve the code for duplicate checking in pcre_dfa_exec(). An incomplete,
303    non-thread-safe patch showed that this can help performance for patterns    non-thread-safe patch showed that this can help performance for patterns
304    where there are many alternatives. However, a simple thread-safe    where there are many alternatives. However, a simple thread-safe
305    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
306    is not an obviously good thing.    is not an obviously good thing.
307    
308  . Make the longest lookbehind available via pcre_fullinfo(). This is not  . Make the longest lookbehind available via pcre_fullinfo(). This is not
309    straightforward because lookbehinds can be nested inside lookbehinds. This    straightforward because lookbehinds can be nested inside lookbehinds. This
310    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
311    the maximum possible lookbehind length. The reason for wanting this is to    the maximum possible lookbehind length. The reason for wanting this is to
312    help when implementing multi-segment matching using pcre_exec() with partial    help when implementing multi-segment matching using pcre_exec() with partial
313    matching and overlapping segments.    matching and overlapping segments.
314    
315  . PCRE cannot at present distinguish between subpatterns with different names,  . PCRE cannot at present distinguish between subpatterns with different names,
316    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
317    remembering *which* subpattern numbered n matched is needed. Bugzilla #760.    remembering *which* subpattern numbered n matched is needed. Bugzilla #760.
318      Now that (*MARK) has been implemented, it can perhaps be used as a way round
319      this problem.
320    
321    . Instead of having #ifdef HAVE_CONFIG_H in each module, put #include
322      "something" and the the #ifdef appears only in one place, in "something".
323    
324  Philip Hazel  Philip Hazel
325  Email local part: ph10  Email local part: ph10
326  Email domain: cam.ac.uk  Email domain: cam.ac.uk
327  Last updated: 26 September 2009  Last updated: 11 October 2011

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