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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 4.1 12-Mar-03
5    ---------------------
7    1. Compiling with gcc -pedantic found a couple of places where casts were
8    needed, and a string in dftables.c that was longer than standard compilers are
9    required to support.
11    2. Compiling with Sun's compiler found a few more places where the code could
12    be tidied up in order to avoid warnings.
14    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
15    first of these names is deprecated in the latest Autoconf in favour of the name
16    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
17    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
18    analogy I have changed it to CFLAGS_FOR_BUILD.
20    4. Added -no-undefined to the linking command in the Makefile, because this is
21    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
22    linking step for the pcreposix library.
24    5. PCRE was failing to diagnose the case of two named groups with the same
25    name.
27    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
28    literal character that is needed in the subject for a match, and scans along to
29    ensure that it is present before embarking on the full matching process. This
30    saves time in cases of nested unlimited repeats that are never going to match.
31    Problem: the scan can take a lot of time if the subject is very long (e.g.
32    megabytes), thus penalizing straightforward matches. It is now done only if the
33    amount of subject to be scanned is less than 1000 bytes.
35    7. A lesser problem with the same optimization is that it was recording the
36    first character of an anchored pattern as "needed", thus provoking a search
37    right along the subject, even when the first match of the pattern was going to
38    fail. The "needed" character is now not set for anchored patterns, unless it
39    follows something in the pattern that is of non-fixed length. Thus, it still
40    fulfils its original purpose of finding quick non-matches in cases of nested
41    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
44    Version 4.0 17-Feb-03
45    ---------------------
47    1. If a comment in an extended regex that started immediately after a meta-item
48    extended to the end of string, PCRE compiled incorrect data. This could lead to
49    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
51    2. Moved to autoconf 2.53 and libtool 1.4.2.
53    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
54    the special perltest8 script is no longer needed - all the tests can be run
55    from a single perltest script.
57    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
58    by \s. It has now been removed in PCRE. This means it isn't recognized as
59    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
60    class [:space:] *does* include VT, thereby creating a mess.
62    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
63    space and tab.
65    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
66    its new features into the main test script, reducing the number of scripts.
68    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
69    were backward compatible, and made the (?i) apply to the whole pattern, as if
70    /i were given. Now it behaves more logically, and applies the option setting
71    only to what follows. PCRE has been changed to follow suit. However, if it
72    finds options settings right at the start of the pattern, it extracts them into
73    the global options, as before. Thus, they show up in the info data.
75    8. Added support for the \Q...\E escape sequence. Characters in between are
76    treated as literals. This is slightly different from Perl in that $ and @ are
77    also handled as literals inside the quotes. In Perl, they will cause variable
78    interpolation. Note the following examples:
80        Pattern            PCRE matches      Perl matches
82        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
83        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
84        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
86    For compatibility with Perl, \Q...\E sequences are recognized inside character
87    classes as well as outside them.
89    9. Re-organized 3 code statements in pcretest to avoid "overflow in
90    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
91    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
92    signed/unsigned warnings.
94    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
95    option for pcretest, so I've replaced it by a simple function that does just
96    that job.
98    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
99    "pcregrep -".
101    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
102    Java package. This provides some syntactic sugar for simple cases of what my
103    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
104    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
105    item, you can use this simplified notation. Note that only makes sense with
106    greedy quantifiers. Consequently, the use of the possessive quantifier forces
107    greediness, whatever the setting of the PCRE_UNGREEDY option.
109    13. A change of greediness default within a pattern was not taking effect at
110    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
111    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
112    was abstracted outside.
114    14. PCRE now supports the \G assertion. It is true when the current matching
115    position is at the start point of the match. This differs from \A when the
116    starting offset is non-zero. Used with the /g option of pcretest (or similar
117    code), it works in the same way as it does for Perl's /g option. If all
118    alternatives of a regex begin with \G, the expression is anchored to the start
119    match position, and the "anchored" flag is set in the compiled expression.
121    15. Some bugs concerning the handling of certain option changes within patterns
122    have been fixed. These applied to options other than (?ims). For example,
123    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
124    been the other way round. Some of this was related to change 7 above.
126    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
127    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
128    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
129    POSIX classes only within a class (e.g. /[[:alpha:]]/).
131    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
132    mode. Unlike ".", it always matches newline, whatever the setting of
133    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
134    assertions. Perl allows it, but it doesn't (in general) work because it can't
135    calculate the length of the lookbehind. At least, that's the case for Perl
136    5.8.0 - I've been told they are going to document that it doesn't work in
137    future.
139    18. Added an error diagnosis for escapes that PCRE does not support: these are
140    \L, \l, \N, \P, \p, \U, \u, and \X.
142    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
143    reading past the end of the pattern in cases such as /[abcd/.
145    20. PCRE was getting more memory than necessary for patterns with classes that
146    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
148    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
149    compiling PCRE for use with Virtual Pascal.
151    22. Small fix to the Makefile to make it work properly if the build is done
152    outside the source tree.
154    23. Added a new extension: a condition to go with recursion. If a conditional
155    subpattern starts with (?(R) the "true" branch is used if recursion has
156    happened, whereas the "false" branch is used only at the top level.
158    24. When there was a very long string of literal characters (over 255 bytes
159    without UTF support, over 250 bytes with UTF support), the computation of how
160    much memory was required could be incorrect, leading to segfaults or other
161    strange effects.
163    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
164    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
165    there was a subsequent back reference to those brackets. This meant that, for
166    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
167    possible to check for precisely this case. All we can do is abandon the
168    optimization if .* occurs inside capturing brackets when there are any back
169    references whatsoever. (See below for a better fix that came later.)
171    26. The handling of the optimization for finding the first character of a
172    non-anchored pattern, and for finding a character that is required later in the
173    match were failing in some cases. This didn't break the matching; it just
174    failed to optimize when it could. The way this is done has been re-implemented.
176    27. Fixed typo in error message for invalid (?R item (it said "(?p").
178    28. Added a new feature that provides some of the functionality that Perl
179    provides with (?{...}). The facility is termed a "callout". The way it is done
180    in PCRE is for the caller to provide an optional function, by setting
181    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
182    global variable. By default it is unset, which disables all calling out. To get
183    the function called, the regex must include (?C) at appropriate points. This
184    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
185    This provides a means of identifying different callout points. When PCRE
186    reaches such a point in the regex, if pcre_callout has been set, the external
187    function is called. It is provided with data in a structure called
188    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
189    matching continues; if it returns a non-zero value, the match at the current
190    point fails. However, backtracking will occur if possible. [This was changed
191    later and other features added - see item 49 below.]
193    29. pcretest is upgraded to test the callout functionality. It provides a
194    callout function that displays information. By default, it shows the start of
195    the match and the current position in the text. There are some new data escapes
196    to vary what happens:
198        \C+         in addition, show current contents of captured substrings
199        \C-         do not supply a callout function
200        \C!n        return 1 when callout number n is reached
201        \C!n!m      return 1 when callout number n is reached for the mth time
203    30. If pcregrep was called with the -l option and just a single file name, it
204    output "<stdin>" if a match was found, instead of the file name.
206    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
207    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
208    pcre_exec(). This saves a malloc/free per call. The default value of
209    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
210    when configuring.
212    32. The default maximum size of a compiled pattern is 64K. There have been a
213    few cases of people hitting this limit. The code now uses macros to handle the
214    storing of links as offsets within the compiled pattern. It defaults to 2-byte
215    links, but this can be changed to 3 or 4 bytes by --with-link-size when
216    configuring. Tests 2 and 5 work only with 2-byte links because they output
217    debugging information about compiled patterns.
219    33. Internal code re-arrangements:
221    (a) Moved the debugging function for printing out a compiled regex into
222        its own source file (printint.c) and used #include to pull it into
223        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
224        separate copies.
226    (b) Defined the list of op-code names for debugging as a macro in
227        internal.h so that it is next to the definition of the opcodes.
229    (c) Defined a table of op-code lengths for simpler skipping along compiled
230        code. This is again a macro in internal.h so that it is next to the
231        definition of the opcodes.
233    34. Added support for recursive calls to individual subpatterns, along the
234    lines of Robin Houston's patch (but implemented somewhat differently).
236    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
237    allow it to read and process whole directories in Win32. This code was
238    contributed by Lionel Fourquaux; it has not been tested by me.
240    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
241    used to name a group. Names consist of alphanumerics and underscores, and must
242    be unique. Back references use the syntax (?P=name) and recursive calls use
243    (?P>name) which is a PCRE extension to the Python extension. Groups still have
244    numbers. The function pcre_fullinfo() can be used after compilation to extract
245    a name/number map. There are three relevant calls:
247      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
248      PCRE_INFO_NAMECOUNT            yields the number of entries
249      PCRE_INFO_NAMETABLE            yields a pointer to the map.
251    The map is a vector of fixed-size entries. The size of each entry depends on
252    the length of the longest name used. The first two bytes of each entry are the
253    group number, most significant byte first. There follows the corresponding
254    name, zero terminated. The names are in alphabetical order.
256    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
257    case instead of 255. Making it the same both with and without UTF-8 support
258    means that the same test output works with both.
260    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
261    calling malloc() with a zero argument.
263    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
264    optimization. I've improved things by keeping a bitmap of backreferences with
265    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
266    fact referenced, the optimization can be applied. It is unlikely that a
267    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
268    the match to follow \n) will appear inside brackets with a number greater than
269    31, but if it does, any back reference > 31 suppresses the optimization.
271    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
272    of disabling numbered capturing parentheses. Any opening parenthesis that is
273    not followed by ? behaves as if it were followed by ?: but named parentheses
274    can still be used for capturing (and they will acquire numbers in the usual
275    way).
277    41. Redesigned the return codes from the match() function into yes/no/error so
278    that errors can be passed back from deep inside the nested calls. A malloc
279    failure while inside a recursive subpattern call now causes the
280    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
282    42. It is now possible to set a limit on the number of times the match()
283    function is called in a call to pcre_exec(). This facility makes it possible to
284    limit the amount of recursion and backtracking, though not in a directly
285    obvious way, because the match() function is used in a number of different
286    circumstances. The count starts from zero for each position in the subject
287    string (for non-anchored patterns). The default limit is, for compatibility, a
288    large number, namely 10 000 000. You can change this in two ways:
290    (a) When configuring PCRE before making, you can use --with-match-limit=n
291        to set a default value for the compiled library.
293    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
294        a different value is set. See 45 below.
296    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
298    43. Added a new function pcre_config(int, void *) to enable run-time extraction
299    of things that can be changed at compile time. The first argument specifies
300    what is wanted and the second points to where the information is to be placed.
301    The current list of available information is:
305    The output is an integer that is set to one if UTF-8 support is available;
306    otherwise it is set to zero.
310    The output is an integer that it set to the value of the code that is used for
311    newline. It is either LF (10) or CR (13).
315    The output is an integer that contains the number of bytes used for internal
316    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
320    The output is an integer that contains the threshold above which the POSIX
321    interface uses malloc() for output vectors. See item 31 above.
325    The output is an unsigned integer that contains the default limit of the number
326    of match() calls in a pcre_exec() execution. See 42 above.
328    44. pcretest has been upgraded by the addition of the -C option. This causes it
329    to extract all the available output from the new pcre_config() function, and to
330    output it. The program then exits immediately.
332    45. A need has arisen to pass over additional data with calls to pcre_exec() in
333    order to support additional features. One way would have been to define
334    pcre_exec2() (for example) with extra arguments, but this would not have been
335    extensible, and would also have required all calls to the original function to
336    be mapped to the new one. Instead, I have chosen to extend the mechanism that
337    is used for passing in "extra" data from pcre_study().
339    The pcre_extra structure is now exposed and defined in pcre.h. It currently
340    contains the following fields:
342      flags         a bitmap indicating which of the following fields are set
343      study_data    opaque data from pcre_study()
344      match_limit   a way of specifying a limit on match() calls for a specific
345                      call to pcre_exec()
346      callout_data  data for callouts (see 49 below)
348    The flag bits are also defined in pcre.h, and are
354    The pcre_study() function now returns one of these new pcre_extra blocks, with
355    the actual study data pointed to by the study_data field, and the
356    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
357    before. That is, this change is entirely upwards-compatible and requires no
358    change to existing code.
360    If you want to pass in additional data to pcre_exec(), you can either place it
361    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
362    block.
364    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
365    data string contains the escape sequence \M, pcretest calls pcre_exec() several
366    times with different match limits, until it finds the minimum value needed for
367    pcre_exec() to complete. The value is then output. This can be instructive; for
368    most simple matches the number is quite small, but for pathological cases it
369    gets very large very quickly.
371    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
372    returns the size of the data block pointed to by the study_data field in a
373    pcre_extra block, that is, the value that was passed as the argument to
374    pcre_malloc() when PCRE was getting memory in which to place the information
375    created by pcre_study(). The fourth argument should point to a size_t variable.
376    pcretest has been extended so that this information is shown after a successful
377    pcre_study() call when information about the compiled regex is being displayed.
379    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
380    because what follows is always an absolute path. (Later: it turns out that this
381    is more than cosmetic for MinGW, because it doesn't like empty path
382    components.)
384    49. Some changes have been made to the callout feature (see 28 above):
386    (i)  A callout function now has three choices for what it returns:
388           0  =>  success, carry on matching
389         > 0  =>  failure at this point, but backtrack if possible
390         < 0  =>  serious error, return this value from pcre_exec()
392         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
393         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
394         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
395         use by callout functions. It will never be used by PCRE itself.
397    (ii) The pcre_extra structure (see 45 above) has a void * field called
398         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
399         pcre_callout_block structure has a field of the same name. The contents of
400         the field passed in the pcre_extra structure are passed to the callout
401         function in the corresponding field in the callout block. This makes it
402         easier to use the same callout-containing regex from multiple threads. For
403         testing, the pcretest program has a new data escape
405           \C*n        pass the number n (may be negative) as callout_data
407         If the callout function in pcretest receives a non-zero value as
408         callout_data, it returns that value.
410    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
411    there were some redundant $(CFLAGS) in commands that are now specified as
412    $(LINK), which already includes $(CFLAGS).
414    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
415    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
416    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
417    one-byte characters throughout. Note that case-insensitive matching applies
418    only to characters whose values are less than 256. PCRE doesn't support the
419    notion of cases for higher-valued characters.
421    (i)   A character class whose characters are all within 0-255 is handled as
422          a bit map, and the map is inverted for negative classes. Previously, a
423          character > 255 always failed to match such a class; however it should
424          match if the class was a negative one (e.g. [^ab]). This has been fixed.
426    (ii)  A negated character class with a single character < 255 is coded as
427          "not this character" (OP_NOT). This wasn't working properly when the test
428          character was multibyte, either singly or repeated.
430    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
431          mode, for example: \x{100}{2,3}.
433    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
434          singly or repeated) now correctly test multibyte characters. However,
435          PCRE doesn't recognize any characters with values greater than 255 as
436          digits, spaces, or word characters. Such characters always match \D, \S,
437          and \W, and never match \d, \s, or \w.
439    (v)   Classes may now contain characters and character ranges with values
440          greater than 255. For example: [ab\x{100}-\x{400}].
442    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
443          PCRE in UTF-8 mode.
445    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
446    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
447    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
448    value.)
450    53. The single man page has become too large. I have therefore split it up into
451    a number of separate man pages. These also give rise to individual HTML pages;
452    these are now put in a separate directory, and there is an index.html page that
453    lists them all. Some hyperlinking between the pages has been installed.
455    54. Added convenience functions for handling named capturing parentheses.
457    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
458    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
459    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
460    are faulted.
462    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
463    calling configure. These values are used when compiling the dftables.c program
464    which is run to generate the source of the default character tables. They
465    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
466    you will need to set these values.
468    57. Updated the building process for Windows DLL, as provided by Fred Cox.
471    Version 3.9 02-Jan-02
472    ---------------------
474    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
476    2. If --disable-static was given, the building process failed when trying to
477    build pcretest and pcregrep. (For some reason it was using libtool to compile
478    them, which is not right, as they aren't part of the library.)
481    Version 3.8 18-Dec-01
482    ---------------------
484    1. The experimental UTF-8 code was completely screwed up. It was packing the
485    bytes in the wrong order. How dumb can you get?
488    Version 3.7 29-Oct-01
489    ---------------------
491    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
492    This caused pcretest, when used on the test data, to segfault. Unfortunately,
493    this didn't happen under Solaris 8, where I normally test things.
495    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
496    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
497    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
498    this fix an hour or so after the initial 3.7 release.)
501    Version 3.6 23-Oct-01
502    ---------------------
504    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
505    offsets passed as NULL with zero offset count.
507    2. The config.guess and config.sub files had not been updated when I moved to
508    the latest autoconf.
511    Version 3.5 15-Aug-01
512    ---------------------
514    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
515    had been forgotten.
517    2. By using declared but undefined structures, we can avoid using "void"
518    definitions in pcre.h while keeping the internal definitions of the structures
519    private.
521    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
522    user point of view, this means that both static and shared libraries are built
523    by default, but this can be individually controlled. More of the work of
524    handling this static/shared cases is now inside libtool instead of PCRE's make
525    file.
527    4. The pcretest utility is now installed along with pcregrep because it is
528    useful for users (to test regexs) and by doing this, it automatically gets
529    relinked by libtool. The documentation has been turned into a man page, so
530    there are now .1, .txt, and .html versions in /doc.
532    5. Upgrades to pcregrep:
533       (i)   Added long-form option names like gnu grep.
534       (ii)  Added --help to list all options with an explanatory phrase.
535       (iii) Added -r, --recursive to recurse into sub-directories.
536       (iv)  Added -f, --file to read patterns from a file.
538    6. pcre_exec() was referring to its "code" argument before testing that
539    argument for NULL (and giving an error if it was NULL).
541    7. Upgraded Makefile.in to allow for compiling in a different directory from
542    the source directory.
544    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
545    options bits, the pointer it was passed was to an int instead of to an unsigned
546    long int. This mattered only on 64-bit systems.
548    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
549    generated) instead of pcre.in, which it its source. Also made the same change
550    in several of the .c files.
552    10. A new release of gcc defines printf() as a macro, which broke pcretest
553    because it had an ifdef in the middle of a string argument for printf(). Fixed
554    by using separate calls to printf().
556    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
557    script, to force use of CR or LF instead of \n in the source. On non-Unix
558    systems, the value can be set in config.h.
560    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
561    absolute limit. Changed the text of the error message to make this clear, and
562    likewise updated the man page.
564    13. The limit of 99 on the number of capturing subpatterns has been removed.
565    The new limit is 65535, which I hope will not be a "real" limit.
568    Version 3.4 22-Aug-00
569    ---------------------
571    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
573    2. Diagnose condition (?(0) as an error instead of crashing on matching.
576    Version 3.3 01-Aug-00
577    ---------------------
579    1. If an octal character was given, but the value was greater than \377, it
580    was not getting masked to the least significant bits, as documented. This could
581    lead to crashes in some systems.
583    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
584    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
586    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
587    These just pass their arguments on to (pcre_free)(), but they are provided
588    because some uses of PCRE bind it to non-C systems that can call its functions,
589    but cannot call free() or pcre_free() directly.
591    4. Add "make test" as a synonym for "make check". Corrected some comments in
592    the Makefile.
594    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
595    Makefile.
597    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
598    command called pgrep for grepping around the active processes.
600    7. Added the beginnings of support for UTF-8 character strings.
602    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
603    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
604    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
605    out for the ar command.)
608    Version 3.2 12-May-00
609    ---------------------
611    This is purely a bug fixing release.
613    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
614    of ZA. This was just one example of several cases that could provoke this bug,
615    which was introduced by change 9 of version 2.00. The code for breaking
616    infinite loops after an iteration that matches an empty string was't working
617    correctly.
619    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
620    when matched against abbab (for example). After matching an empty string, it
621    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
622    caused it to match further down the string than it should.
624    3. The code contained an inclusion of sys/types.h. It isn't clear why this
625    was there because it doesn't seem to be needed, and it causes trouble on some
626    systems, as it is not a Standard C header. It has been removed.
628    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
629    were reported on the Macintosh. The changes were from
631      while ((c = *(++ptr)) != 0 && c != '\n');
632    to
633      while ((c = *(++ptr)) != 0 && c != '\n') ;
635    Totally extraordinary, but if that's what it takes...
637    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
638    available. Added HAVE_BCOPY and an autoconf test for it; if neither
639    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
640    assumes the way PCRE uses memmove() (always moving upwards).
642    6. PCRE is being used in one environment where strchr() is not available. There
643    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
644    faster code anyway.
647    Version 3.1 09-Feb-00
648    ---------------------
650    The only change in this release is the fixing of some bugs in Makefile.in for
651    the "install" target:
653    (1) It was failing to install pcreposix.h.
655    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
658    Version 3.0 01-Feb-00
659    ---------------------
661    1. Add support for the /+ modifier to perltest (to output $` like it does in
662    pcretest).
664    2. Add support for the /g modifier to perltest.
666    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
667    matches null strings.
669    4. Fix perltest so that it doesn't do unwanted things when fed an empty
670    pattern. Perl treats empty patterns specially - it reuses the most recent
671    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
672    effect.
674    5. The POSIX interface was broken in that it was just handing over the POSIX
675    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
676    required a bigger vector, with some working space on the end. This means that
677    the POSIX wrapper now has to get and free some memory, and copy the results.
679    6. Added some simple autoconf support, placing the test data and the
680    documentation in separate directories, re-organizing some of the
681    information files, and making it build pcre-config (a GNU standard). Also added
682    libtool support for building PCRE as a shared library, which is now the
683    default.
685    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
686    09 are not valid octal constants. Single digits will be used for minor values
687    less than 10.
689    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
690    existing programs that set these in the POSIX interface can use PCRE without
691    modification.
693    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
694    return all that pcre_info() returns, plus additional data. The pcre_info()
695    function is retained for compatibility, but is considered to be obsolete.
697    10. Added experimental recursion feature (?R) to handle one common case that
698    Perl 5.6 will be able to do with (?p{...}).
700    11. Added support for POSIX character classes like [:alpha:], which Perl is
701    adopting.
704    Version 2.08 31-Aug-99
705    ----------------------
707    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
708    trying to match at the startoffset position, but instead was moving forward to
709    the next newline as if a previous match had failed.
711    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
712    and could get into a loop if a null string was matched other than at the start
713    of the subject.
715    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
716    be distinguished at compile time, and for completeness also added PCRE_DATE.
718    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
719    in GnuWin32 environments.
722    Version 2.07 29-Jul-99
723    ----------------------
725    1. The documentation is now supplied in plain text form and HTML as well as in
726    the form of man page sources.
728    2. C++ compilers don't like assigning (void *) values to other pointer types.
729    In particular this affects malloc(). Although there is no problem in Standard
730    C, I've put in casts to keep C++ compilers happy.
732    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
733    should be (const char *).
735    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
736    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
737    However, I haven't made this a standard facility. The documentation doesn't
738    mention it, and the Makefile doesn't support it.
740    5. The Makefile now contains an "install" target, with editable destinations at
741    the top of the file. The pcretest program is not installed.
743    6. pgrep -V now gives the PCRE version number and date.
745    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
746    causing the entire string to be ignored, instead of just the last character.
748    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
749    non-matching string, it can take a very, very long time, even for strings of
750    quite modest length, because of the nested recursion. PCRE now does better in
751    some of these cases. It does this by remembering the last required literal
752    character in the pattern, and pre-searching the subject to ensure it is present
753    before running the real match. In other words, it applies a heuristic to detect
754    some types of certain failure quickly, and in the above example, if presented
755    with a string that has no trailing " it gives "no match" very quickly.
757    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
758    other alternatives are tried instead.
761    Version 2.06 09-Jun-99
762    ----------------------
764    1. Change pcretest's output for amount of store used to show just the code
765    space, because the remainder (the data block) varies in size between 32-bit and
766    64-bit systems.
768    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
769    start matching at. This allows lookbehinds to work when searching for multiple
770    occurrences in a string.
772    3. Added additional options to pcretest for testing multiple occurrences:
774       /+   outputs the rest of the string that follows a match
775       /g   loops for multiple occurrences, using the new startoffset argument
776       /G   loops for multiple occurrences by passing an incremented pointer
778    4. PCRE wasn't doing the "first character" optimization for patterns starting
779    with \b or \B, though it was doing it for other lookbehind assertions. That is,
780    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
781    the letter 'x'. On long subject strings, this gives a significant speed-up.
784    Version 2.05 21-Apr-99
785    ----------------------
787    1. Changed the type of magic_number from int to long int so that it works
788    properly on 16-bit systems.
790    2. Fixed a bug which caused patterns starting with .* not to work correctly
791    when the subject string contained newline characters. PCRE was assuming
792    anchoring for such patterns in all cases, which is not correct because .* will
793    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
794    DOTALL is set at top level; otherwise it knows that patterns starting with .*
795    must be retried after every newline in the subject.
798    Version 2.04 18-Feb-99
799    ----------------------
801    1. For parenthesized subpatterns with repeats whose minimum was zero, the
802    computation of the store needed to hold the pattern was incorrect (too large).
803    If such patterns were nested a few deep, this could multiply and become a real
804    problem.
806    2. Added /M option to pcretest to show the memory requirement of a specific
807    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
809    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
810    compiled in such a way that the backtracking after subsequent failure was
811    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
812    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
815    Version 2.03 02-Feb-99
816    ----------------------
818    1. Fixed typo and small mistake in man page.
820    2. Added 4th condition (GPL supersedes if conflict) and created separate
821    LICENCE file containing the conditions.
823    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
824    Perl, that is the internal \ allows the delimiter to be included in the
825    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
826    the final delimiter, add \ to the end of the pattern (to test the error).
828    4. Added the convenience functions for extracting substrings after a successful
829    match. Updated pcretest to make it able to test these functions.
832  Version 2.02 14-Jan-99  Version 2.02 14-Jan-99
833  ----------------------  ----------------------

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