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1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 nigel 69 Version 4.3 21-May-03
5     ---------------------
6    
7     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
8     Makefile.
9    
10     2. Some refactoring to improve the quality of the code:
11    
12     (i) The utf8_table... variables are now declared "const".
13    
14     (ii) The code for \cx, which used the "case flipping" table to upper case
15     lower case letters, now just substracts 32. This is ASCII-specific,
16     but the whole concept of \cx is ASCII-specific, so it seems
17     reasonable.
18    
19     (iii) PCRE was using its character types table to recognize decimal and
20     hexadecimal digits in the pattern. This is silly, because it handles
21     only 0-9, a-f, and A-F, but the character types table is locale-
22     specific, which means strange things might happen. A private
23     table is now used for this - though it costs 256 bytes, a table is
24     much faster than multiple explicit tests. Of course, the standard
25     character types table is still used for matching digits in subject
26     strings against \d.
27    
28     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
29     ending in _t are). So I've renamed it as ESC_tee.
30    
31     3. The first argument for regexec() in the POSIX wrapper should have been
32     defined as "const".
33    
34     4. Changed pcretest to use malloc() for its buffers so that they can be
35     Electric Fenced for debugging.
36    
37     5. There were several places in the code where, in UTF-8 mode, PCRE would try
38     to read one or more bytes before the start of the subject string. Often this
39     had no effect on PCRE's behaviour, but in some circumstances it could
40     provoke a segmentation fault.
41    
42     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
43     to try to read one or more bytes before the start of the subject string.
44    
45     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
46     UTF-8 support could misbehave in various ways if the subject string
47     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
48     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
49     back over UTF-8 characters.)
50    
51    
52 nigel 67 Version 4.2 14-Apr-03
53     ---------------------
54    
55     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
56    
57     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
58     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
59     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
60     [WIN_PREFIX]: new variable, "cyg" for Cygwin
61     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
62     and BUILD_EXEEXT
63     Note: automatic setting of the BUILD variables is not yet working
64     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
65     compile-time but not at link-time
66     [LINK]: use for linking executables only
67     make different versions for Windows and non-Windows
68     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
69     libraries
70     [LINK_FOR_BUILD]: new variable
71     [OBJEXT]: use throughout
72     [EXEEXT]: use throughout
73     <winshared>: new target
74     <wininstall>: new target
75     <dftables.o>: use native compiler
76     <dftables>: use native linker
77     <install>: handle Windows platform correctly
78     <clean>: ditto
79     <check>: ditto
80     copy DLL to top builddir before testing
81    
82     As part of these changes, -no-undefined was removed again. This was reported
83     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
84     in any case.
85    
86     3. Some tidies to get rid of compiler warnings:
87    
88     . In the match_data structure, match_limit was an unsigned long int, whereas
89     match_call_count was an int. I've made them both unsigned long ints.
90    
91     . In pcretest the fact that a const uschar * doesn't automatically cast to
92     a void * provoked a warning.
93    
94     . Turning on some more compiler warnings threw up some "shadow" variables
95     and a few more missing casts.
96    
97     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
98     option, a class that contained a single character with a value between 128
99     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
100    
101     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
102     option, a class that contained several characters, but with at least one
103     whose value was between 128 and 255 caused PCRE to crash.
104    
105    
106 nigel 65 Version 4.1 12-Mar-03
107     ---------------------
108 nigel 63
109 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
110     needed, and a string in dftables.c that was longer than standard compilers are
111     required to support.
112    
113     2. Compiling with Sun's compiler found a few more places where the code could
114     be tidied up in order to avoid warnings.
115    
116     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
117     first of these names is deprecated in the latest Autoconf in favour of the name
118     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
119     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
120     analogy I have changed it to CFLAGS_FOR_BUILD.
121    
122     4. Added -no-undefined to the linking command in the Makefile, because this is
123     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
124     linking step for the pcreposix library.
125    
126     5. PCRE was failing to diagnose the case of two named groups with the same
127     name.
128    
129     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
130     literal character that is needed in the subject for a match, and scans along to
131     ensure that it is present before embarking on the full matching process. This
132     saves time in cases of nested unlimited repeats that are never going to match.
133     Problem: the scan can take a lot of time if the subject is very long (e.g.
134     megabytes), thus penalizing straightforward matches. It is now done only if the
135     amount of subject to be scanned is less than 1000 bytes.
136    
137     7. A lesser problem with the same optimization is that it was recording the
138     first character of an anchored pattern as "needed", thus provoking a search
139     right along the subject, even when the first match of the pattern was going to
140     fail. The "needed" character is now not set for anchored patterns, unless it
141     follows something in the pattern that is of non-fixed length. Thus, it still
142     fulfils its original purpose of finding quick non-matches in cases of nested
143     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
144    
145    
146     Version 4.0 17-Feb-03
147     ---------------------
148    
149 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
150     extended to the end of string, PCRE compiled incorrect data. This could lead to
151     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
152    
153     2. Moved to autoconf 2.53 and libtool 1.4.2.
154    
155     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
156     the special perltest8 script is no longer needed - all the tests can be run
157     from a single perltest script.
158    
159     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
160     by \s. It has now been removed in PCRE. This means it isn't recognized as
161     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
162     class [:space:] *does* include VT, thereby creating a mess.
163    
164     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
165     space and tab.
166    
167     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
168     its new features into the main test script, reducing the number of scripts.
169    
170     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
171     were backward compatible, and made the (?i) apply to the whole pattern, as if
172     /i were given. Now it behaves more logically, and applies the option setting
173     only to what follows. PCRE has been changed to follow suit. However, if it
174     finds options settings right at the start of the pattern, it extracts them into
175     the global options, as before. Thus, they show up in the info data.
176    
177     8. Added support for the \Q...\E escape sequence. Characters in between are
178     treated as literals. This is slightly different from Perl in that $ and @ are
179     also handled as literals inside the quotes. In Perl, they will cause variable
180     interpolation. Note the following examples:
181    
182     Pattern PCRE matches Perl matches
183    
184     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
185     \Qabc\$xyz\E abc\$xyz abc\$xyz
186     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
187    
188     For compatibility with Perl, \Q...\E sequences are recognized inside character
189     classes as well as outside them.
190    
191     9. Re-organized 3 code statements in pcretest to avoid "overflow in
192     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
193     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
194     signed/unsigned warnings.
195    
196     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
197     option for pcretest, so I've replaced it by a simple function that does just
198     that job.
199    
200     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
201     "pcregrep -".
202    
203     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
204     Java package. This provides some syntactic sugar for simple cases of what my
205     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
206     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
207     item, you can use this simplified notation. Note that only makes sense with
208     greedy quantifiers. Consequently, the use of the possessive quantifier forces
209     greediness, whatever the setting of the PCRE_UNGREEDY option.
210    
211     13. A change of greediness default within a pattern was not taking effect at
212     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
213     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
214     was abstracted outside.
215    
216     14. PCRE now supports the \G assertion. It is true when the current matching
217     position is at the start point of the match. This differs from \A when the
218     starting offset is non-zero. Used with the /g option of pcretest (or similar
219     code), it works in the same way as it does for Perl's /g option. If all
220     alternatives of a regex begin with \G, the expression is anchored to the start
221     match position, and the "anchored" flag is set in the compiled expression.
222    
223     15. Some bugs concerning the handling of certain option changes within patterns
224     have been fixed. These applied to options other than (?ims). For example,
225     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
226     been the other way round. Some of this was related to change 7 above.
227    
228     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
229     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
230     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
231     POSIX classes only within a class (e.g. /[[:alpha:]]/).
232    
233     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
234     mode. Unlike ".", it always matches newline, whatever the setting of
235     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
236     assertions. Perl allows it, but it doesn't (in general) work because it can't
237     calculate the length of the lookbehind. At least, that's the case for Perl
238     5.8.0 - I've been told they are going to document that it doesn't work in
239     future.
240    
241     18. Added an error diagnosis for escapes that PCRE does not support: these are
242     \L, \l, \N, \P, \p, \U, \u, and \X.
243    
244     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
245     reading past the end of the pattern in cases such as /[abcd/.
246    
247     20. PCRE was getting more memory than necessary for patterns with classes that
248     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
249    
250     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
251     compiling PCRE for use with Virtual Pascal.
252    
253     22. Small fix to the Makefile to make it work properly if the build is done
254     outside the source tree.
255    
256     23. Added a new extension: a condition to go with recursion. If a conditional
257     subpattern starts with (?(R) the "true" branch is used if recursion has
258     happened, whereas the "false" branch is used only at the top level.
259    
260     24. When there was a very long string of literal characters (over 255 bytes
261     without UTF support, over 250 bytes with UTF support), the computation of how
262     much memory was required could be incorrect, leading to segfaults or other
263     strange effects.
264    
265     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
266     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
267     there was a subsequent back reference to those brackets. This meant that, for
268     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
269     possible to check for precisely this case. All we can do is abandon the
270     optimization if .* occurs inside capturing brackets when there are any back
271     references whatsoever. (See below for a better fix that came later.)
272    
273     26. The handling of the optimization for finding the first character of a
274     non-anchored pattern, and for finding a character that is required later in the
275     match were failing in some cases. This didn't break the matching; it just
276     failed to optimize when it could. The way this is done has been re-implemented.
277    
278     27. Fixed typo in error message for invalid (?R item (it said "(?p").
279    
280     28. Added a new feature that provides some of the functionality that Perl
281     provides with (?{...}). The facility is termed a "callout". The way it is done
282     in PCRE is for the caller to provide an optional function, by setting
283     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
284     global variable. By default it is unset, which disables all calling out. To get
285     the function called, the regex must include (?C) at appropriate points. This
286     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
287     This provides a means of identifying different callout points. When PCRE
288     reaches such a point in the regex, if pcre_callout has been set, the external
289     function is called. It is provided with data in a structure called
290     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
291     matching continues; if it returns a non-zero value, the match at the current
292     point fails. However, backtracking will occur if possible. [This was changed
293     later and other features added - see item 49 below.]
294    
295     29. pcretest is upgraded to test the callout functionality. It provides a
296     callout function that displays information. By default, it shows the start of
297     the match and the current position in the text. There are some new data escapes
298     to vary what happens:
299    
300     \C+ in addition, show current contents of captured substrings
301     \C- do not supply a callout function
302     \C!n return 1 when callout number n is reached
303     \C!n!m return 1 when callout number n is reached for the mth time
304    
305     30. If pcregrep was called with the -l option and just a single file name, it
306     output "<stdin>" if a match was found, instead of the file name.
307    
308     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
309     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
310     pcre_exec(). This saves a malloc/free per call. The default value of
311     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
312     when configuring.
313    
314     32. The default maximum size of a compiled pattern is 64K. There have been a
315     few cases of people hitting this limit. The code now uses macros to handle the
316     storing of links as offsets within the compiled pattern. It defaults to 2-byte
317     links, but this can be changed to 3 or 4 bytes by --with-link-size when
318     configuring. Tests 2 and 5 work only with 2-byte links because they output
319     debugging information about compiled patterns.
320    
321     33. Internal code re-arrangements:
322    
323     (a) Moved the debugging function for printing out a compiled regex into
324     its own source file (printint.c) and used #include to pull it into
325     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
326     separate copies.
327    
328     (b) Defined the list of op-code names for debugging as a macro in
329     internal.h so that it is next to the definition of the opcodes.
330    
331     (c) Defined a table of op-code lengths for simpler skipping along compiled
332     code. This is again a macro in internal.h so that it is next to the
333     definition of the opcodes.
334    
335     34. Added support for recursive calls to individual subpatterns, along the
336     lines of Robin Houston's patch (but implemented somewhat differently).
337    
338     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
339     allow it to read and process whole directories in Win32. This code was
340     contributed by Lionel Fourquaux; it has not been tested by me.
341    
342     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
343     used to name a group. Names consist of alphanumerics and underscores, and must
344     be unique. Back references use the syntax (?P=name) and recursive calls use
345     (?P>name) which is a PCRE extension to the Python extension. Groups still have
346     numbers. The function pcre_fullinfo() can be used after compilation to extract
347     a name/number map. There are three relevant calls:
348    
349     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
350     PCRE_INFO_NAMECOUNT yields the number of entries
351     PCRE_INFO_NAMETABLE yields a pointer to the map.
352    
353     The map is a vector of fixed-size entries. The size of each entry depends on
354     the length of the longest name used. The first two bytes of each entry are the
355     group number, most significant byte first. There follows the corresponding
356     name, zero terminated. The names are in alphabetical order.
357    
358     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
359     case instead of 255. Making it the same both with and without UTF-8 support
360     means that the same test output works with both.
361    
362     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
363     calling malloc() with a zero argument.
364    
365     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
366     optimization. I've improved things by keeping a bitmap of backreferences with
367     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
368     fact referenced, the optimization can be applied. It is unlikely that a
369     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
370     the match to follow \n) will appear inside brackets with a number greater than
371     31, but if it does, any back reference > 31 suppresses the optimization.
372    
373     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
374     of disabling numbered capturing parentheses. Any opening parenthesis that is
375     not followed by ? behaves as if it were followed by ?: but named parentheses
376     can still be used for capturing (and they will acquire numbers in the usual
377     way).
378    
379     41. Redesigned the return codes from the match() function into yes/no/error so
380     that errors can be passed back from deep inside the nested calls. A malloc
381     failure while inside a recursive subpattern call now causes the
382     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
383    
384     42. It is now possible to set a limit on the number of times the match()
385     function is called in a call to pcre_exec(). This facility makes it possible to
386     limit the amount of recursion and backtracking, though not in a directly
387     obvious way, because the match() function is used in a number of different
388     circumstances. The count starts from zero for each position in the subject
389     string (for non-anchored patterns). The default limit is, for compatibility, a
390     large number, namely 10 000 000. You can change this in two ways:
391    
392     (a) When configuring PCRE before making, you can use --with-match-limit=n
393     to set a default value for the compiled library.
394    
395     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
396     a different value is set. See 45 below.
397    
398     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
399    
400     43. Added a new function pcre_config(int, void *) to enable run-time extraction
401     of things that can be changed at compile time. The first argument specifies
402     what is wanted and the second points to where the information is to be placed.
403     The current list of available information is:
404    
405     PCRE_CONFIG_UTF8
406    
407     The output is an integer that is set to one if UTF-8 support is available;
408     otherwise it is set to zero.
409    
410     PCRE_CONFIG_NEWLINE
411    
412     The output is an integer that it set to the value of the code that is used for
413     newline. It is either LF (10) or CR (13).
414    
415     PCRE_CONFIG_LINK_SIZE
416    
417     The output is an integer that contains the number of bytes used for internal
418     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
419    
420     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
421    
422     The output is an integer that contains the threshold above which the POSIX
423     interface uses malloc() for output vectors. See item 31 above.
424    
425     PCRE_CONFIG_MATCH_LIMIT
426    
427     The output is an unsigned integer that contains the default limit of the number
428     of match() calls in a pcre_exec() execution. See 42 above.
429    
430     44. pcretest has been upgraded by the addition of the -C option. This causes it
431     to extract all the available output from the new pcre_config() function, and to
432     output it. The program then exits immediately.
433    
434     45. A need has arisen to pass over additional data with calls to pcre_exec() in
435     order to support additional features. One way would have been to define
436     pcre_exec2() (for example) with extra arguments, but this would not have been
437     extensible, and would also have required all calls to the original function to
438     be mapped to the new one. Instead, I have chosen to extend the mechanism that
439     is used for passing in "extra" data from pcre_study().
440    
441     The pcre_extra structure is now exposed and defined in pcre.h. It currently
442     contains the following fields:
443    
444     flags a bitmap indicating which of the following fields are set
445     study_data opaque data from pcre_study()
446     match_limit a way of specifying a limit on match() calls for a specific
447     call to pcre_exec()
448     callout_data data for callouts (see 49 below)
449    
450     The flag bits are also defined in pcre.h, and are
451    
452     PCRE_EXTRA_STUDY_DATA
453     PCRE_EXTRA_MATCH_LIMIT
454     PCRE_EXTRA_CALLOUT_DATA
455    
456     The pcre_study() function now returns one of these new pcre_extra blocks, with
457     the actual study data pointed to by the study_data field, and the
458     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
459     before. That is, this change is entirely upwards-compatible and requires no
460     change to existing code.
461    
462     If you want to pass in additional data to pcre_exec(), you can either place it
463     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
464     block.
465    
466     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
467     data string contains the escape sequence \M, pcretest calls pcre_exec() several
468     times with different match limits, until it finds the minimum value needed for
469     pcre_exec() to complete. The value is then output. This can be instructive; for
470     most simple matches the number is quite small, but for pathological cases it
471     gets very large very quickly.
472    
473     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
474     returns the size of the data block pointed to by the study_data field in a
475     pcre_extra block, that is, the value that was passed as the argument to
476     pcre_malloc() when PCRE was getting memory in which to place the information
477     created by pcre_study(). The fourth argument should point to a size_t variable.
478     pcretest has been extended so that this information is shown after a successful
479     pcre_study() call when information about the compiled regex is being displayed.
480    
481     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
482     because what follows is always an absolute path. (Later: it turns out that this
483     is more than cosmetic for MinGW, because it doesn't like empty path
484     components.)
485    
486     49. Some changes have been made to the callout feature (see 28 above):
487    
488     (i) A callout function now has three choices for what it returns:
489    
490     0 => success, carry on matching
491     > 0 => failure at this point, but backtrack if possible
492     < 0 => serious error, return this value from pcre_exec()
493    
494     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
495     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
496     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
497     use by callout functions. It will never be used by PCRE itself.
498    
499     (ii) The pcre_extra structure (see 45 above) has a void * field called
500     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
501     pcre_callout_block structure has a field of the same name. The contents of
502     the field passed in the pcre_extra structure are passed to the callout
503     function in the corresponding field in the callout block. This makes it
504     easier to use the same callout-containing regex from multiple threads. For
505     testing, the pcretest program has a new data escape
506    
507     \C*n pass the number n (may be negative) as callout_data
508    
509     If the callout function in pcretest receives a non-zero value as
510     callout_data, it returns that value.
511    
512     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
513     there were some redundant $(CFLAGS) in commands that are now specified as
514     $(LINK), which already includes $(CFLAGS).
515    
516     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
517     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
518     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
519     one-byte characters throughout. Note that case-insensitive matching applies
520     only to characters whose values are less than 256. PCRE doesn't support the
521     notion of cases for higher-valued characters.
522    
523     (i) A character class whose characters are all within 0-255 is handled as
524     a bit map, and the map is inverted for negative classes. Previously, a
525     character > 255 always failed to match such a class; however it should
526     match if the class was a negative one (e.g. [^ab]). This has been fixed.
527    
528     (ii) A negated character class with a single character < 255 is coded as
529     "not this character" (OP_NOT). This wasn't working properly when the test
530     character was multibyte, either singly or repeated.
531    
532     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
533     mode, for example: \x{100}{2,3}.
534    
535     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
536     singly or repeated) now correctly test multibyte characters. However,
537     PCRE doesn't recognize any characters with values greater than 255 as
538     digits, spaces, or word characters. Such characters always match \D, \S,
539     and \W, and never match \d, \s, or \w.
540    
541     (v) Classes may now contain characters and character ranges with values
542     greater than 255. For example: [ab\x{100}-\x{400}].
543    
544     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
545     PCRE in UTF-8 mode.
546    
547     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
548     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
549     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
550     value.)
551    
552     53. The single man page has become too large. I have therefore split it up into
553     a number of separate man pages. These also give rise to individual HTML pages;
554     these are now put in a separate directory, and there is an index.html page that
555     lists them all. Some hyperlinking between the pages has been installed.
556    
557     54. Added convenience functions for handling named capturing parentheses.
558    
559     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
560     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
561     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
562     are faulted.
563    
564     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
565     calling configure. These values are used when compiling the dftables.c program
566     which is run to generate the source of the default character tables. They
567     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
568     you will need to set these values.
569    
570     57. Updated the building process for Windows DLL, as provided by Fred Cox.
571    
572    
573     Version 3.9 02-Jan-02
574 nigel 61 ---------------------
575    
576     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
577    
578     2. If --disable-static was given, the building process failed when trying to
579     build pcretest and pcregrep. (For some reason it was using libtool to compile
580     them, which is not right, as they aren't part of the library.)
581    
582    
583 nigel 59 Version 3.8 18-Dec-01
584     ---------------------
585    
586     1. The experimental UTF-8 code was completely screwed up. It was packing the
587     bytes in the wrong order. How dumb can you get?
588    
589    
590 nigel 57 Version 3.7 29-Oct-01
591     ---------------------
592    
593     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
594     This caused pcretest, when used on the test data, to segfault. Unfortunately,
595     this didn't happen under Solaris 8, where I normally test things.
596    
597 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
598     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
599     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
600     this fix an hour or so after the initial 3.7 release.)
601 nigel 57
602 nigel 59
603 nigel 55 Version 3.6 23-Oct-01
604     ---------------------
605    
606     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
607     offsets passed as NULL with zero offset count.
608    
609     2. The config.guess and config.sub files had not been updated when I moved to
610     the latest autoconf.
611    
612    
613 nigel 53 Version 3.5 15-Aug-01
614     ---------------------
615 nigel 5
616 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
617     had been forgotten.
618    
619     2. By using declared but undefined structures, we can avoid using "void"
620     definitions in pcre.h while keeping the internal definitions of the structures
621     private.
622    
623     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
624     user point of view, this means that both static and shared libraries are built
625     by default, but this can be individually controlled. More of the work of
626     handling this static/shared cases is now inside libtool instead of PCRE's make
627     file.
628    
629     4. The pcretest utility is now installed along with pcregrep because it is
630     useful for users (to test regexs) and by doing this, it automatically gets
631     relinked by libtool. The documentation has been turned into a man page, so
632     there are now .1, .txt, and .html versions in /doc.
633    
634     5. Upgrades to pcregrep:
635     (i) Added long-form option names like gnu grep.
636     (ii) Added --help to list all options with an explanatory phrase.
637     (iii) Added -r, --recursive to recurse into sub-directories.
638     (iv) Added -f, --file to read patterns from a file.
639    
640     6. pcre_exec() was referring to its "code" argument before testing that
641     argument for NULL (and giving an error if it was NULL).
642    
643     7. Upgraded Makefile.in to allow for compiling in a different directory from
644     the source directory.
645    
646     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
647     options bits, the pointer it was passed was to an int instead of to an unsigned
648     long int. This mattered only on 64-bit systems.
649    
650     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
651     generated) instead of pcre.in, which it its source. Also made the same change
652     in several of the .c files.
653    
654     10. A new release of gcc defines printf() as a macro, which broke pcretest
655     because it had an ifdef in the middle of a string argument for printf(). Fixed
656     by using separate calls to printf().
657    
658     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
659     script, to force use of CR or LF instead of \n in the source. On non-Unix
660     systems, the value can be set in config.h.
661    
662     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
663     absolute limit. Changed the text of the error message to make this clear, and
664     likewise updated the man page.
665    
666     13. The limit of 99 on the number of capturing subpatterns has been removed.
667     The new limit is 65535, which I hope will not be a "real" limit.
668    
669    
670 nigel 51 Version 3.4 22-Aug-00
671     ---------------------
672    
673     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
674    
675     2. Diagnose condition (?(0) as an error instead of crashing on matching.
676    
677    
678 nigel 49 Version 3.3 01-Aug-00
679     ---------------------
680    
681     1. If an octal character was given, but the value was greater than \377, it
682     was not getting masked to the least significant bits, as documented. This could
683     lead to crashes in some systems.
684    
685     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
686     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
687    
688     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
689     These just pass their arguments on to (pcre_free)(), but they are provided
690     because some uses of PCRE bind it to non-C systems that can call its functions,
691     but cannot call free() or pcre_free() directly.
692    
693     4. Add "make test" as a synonym for "make check". Corrected some comments in
694     the Makefile.
695    
696     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
697     Makefile.
698    
699     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
700     command called pgrep for grepping around the active processes.
701    
702     7. Added the beginnings of support for UTF-8 character strings.
703    
704     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
705     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
706     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
707     out for the ar command.)
708    
709    
710 nigel 47 Version 3.2 12-May-00
711     ---------------------
712    
713     This is purely a bug fixing release.
714    
715     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
716     of ZA. This was just one example of several cases that could provoke this bug,
717     which was introduced by change 9 of version 2.00. The code for breaking
718     infinite loops after an iteration that matches an empty string was't working
719     correctly.
720    
721     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
722     when matched against abbab (for example). After matching an empty string, it
723     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
724     caused it to match further down the string than it should.
725    
726     3. The code contained an inclusion of sys/types.h. It isn't clear why this
727     was there because it doesn't seem to be needed, and it causes trouble on some
728     systems, as it is not a Standard C header. It has been removed.
729    
730     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
731     were reported on the Macintosh. The changes were from
732    
733     while ((c = *(++ptr)) != 0 && c != '\n');
734     to
735     while ((c = *(++ptr)) != 0 && c != '\n') ;
736    
737     Totally extraordinary, but if that's what it takes...
738    
739     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
740     available. Added HAVE_BCOPY and an autoconf test for it; if neither
741     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
742     assumes the way PCRE uses memmove() (always moving upwards).
743    
744     6. PCRE is being used in one environment where strchr() is not available. There
745     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
746     faster code anyway.
747    
748    
749 nigel 45 Version 3.1 09-Feb-00
750     ---------------------
751    
752     The only change in this release is the fixing of some bugs in Makefile.in for
753     the "install" target:
754    
755     (1) It was failing to install pcreposix.h.
756    
757     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
758    
759    
760 nigel 43 Version 3.0 01-Feb-00
761     ---------------------
762 nigel 41
763     1. Add support for the /+ modifier to perltest (to output $` like it does in
764     pcretest).
765    
766     2. Add support for the /g modifier to perltest.
767    
768     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
769     matches null strings.
770    
771     4. Fix perltest so that it doesn't do unwanted things when fed an empty
772     pattern. Perl treats empty patterns specially - it reuses the most recent
773     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
774     effect.
775    
776     5. The POSIX interface was broken in that it was just handing over the POSIX
777     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
778     required a bigger vector, with some working space on the end. This means that
779     the POSIX wrapper now has to get and free some memory, and copy the results.
780    
781 nigel 43 6. Added some simple autoconf support, placing the test data and the
782     documentation in separate directories, re-organizing some of the
783     information files, and making it build pcre-config (a GNU standard). Also added
784     libtool support for building PCRE as a shared library, which is now the
785     default.
786 nigel 41
787 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
788     09 are not valid octal constants. Single digits will be used for minor values
789     less than 10.
790    
791     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
792     existing programs that set these in the POSIX interface can use PCRE without
793     modification.
794    
795     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
796     return all that pcre_info() returns, plus additional data. The pcre_info()
797     function is retained for compatibility, but is considered to be obsolete.
798    
799     10. Added experimental recursion feature (?R) to handle one common case that
800     Perl 5.6 will be able to do with (?p{...}).
801    
802     11. Added support for POSIX character classes like [:alpha:], which Perl is
803     adopting.
804    
805    
806 nigel 39 Version 2.08 31-Aug-99
807     ----------------------
808    
809     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
810     trying to match at the startoffset position, but instead was moving forward to
811     the next newline as if a previous match had failed.
812    
813     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
814     and could get into a loop if a null string was matched other than at the start
815     of the subject.
816    
817     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
818     be distinguished at compile time, and for completeness also added PCRE_DATE.
819    
820     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
821     in GnuWin32 environments.
822    
823    
824 nigel 37 Version 2.07 29-Jul-99
825     ----------------------
826    
827     1. The documentation is now supplied in plain text form and HTML as well as in
828     the form of man page sources.
829    
830     2. C++ compilers don't like assigning (void *) values to other pointer types.
831     In particular this affects malloc(). Although there is no problem in Standard
832     C, I've put in casts to keep C++ compilers happy.
833    
834     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
835     should be (const char *).
836    
837     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
838     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
839     However, I haven't made this a standard facility. The documentation doesn't
840     mention it, and the Makefile doesn't support it.
841    
842     5. The Makefile now contains an "install" target, with editable destinations at
843     the top of the file. The pcretest program is not installed.
844    
845     6. pgrep -V now gives the PCRE version number and date.
846    
847     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
848     causing the entire string to be ignored, instead of just the last character.
849    
850     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
851     non-matching string, it can take a very, very long time, even for strings of
852     quite modest length, because of the nested recursion. PCRE now does better in
853     some of these cases. It does this by remembering the last required literal
854     character in the pattern, and pre-searching the subject to ensure it is present
855     before running the real match. In other words, it applies a heuristic to detect
856     some types of certain failure quickly, and in the above example, if presented
857     with a string that has no trailing " it gives "no match" very quickly.
858    
859     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
860     other alternatives are tried instead.
861    
862    
863 nigel 35 Version 2.06 09-Jun-99
864     ----------------------
865    
866     1. Change pcretest's output for amount of store used to show just the code
867     space, because the remainder (the data block) varies in size between 32-bit and
868     64-bit systems.
869    
870     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
871     start matching at. This allows lookbehinds to work when searching for multiple
872     occurrences in a string.
873    
874     3. Added additional options to pcretest for testing multiple occurrences:
875    
876     /+ outputs the rest of the string that follows a match
877     /g loops for multiple occurrences, using the new startoffset argument
878     /G loops for multiple occurrences by passing an incremented pointer
879    
880     4. PCRE wasn't doing the "first character" optimization for patterns starting
881     with \b or \B, though it was doing it for other lookbehind assertions. That is,
882     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
883     the letter 'x'. On long subject strings, this gives a significant speed-up.
884    
885    
886 nigel 33 Version 2.05 21-Apr-99
887     ----------------------
888    
889     1. Changed the type of magic_number from int to long int so that it works
890     properly on 16-bit systems.
891    
892     2. Fixed a bug which caused patterns starting with .* not to work correctly
893     when the subject string contained newline characters. PCRE was assuming
894     anchoring for such patterns in all cases, which is not correct because .* will
895     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
896     DOTALL is set at top level; otherwise it knows that patterns starting with .*
897     must be retried after every newline in the subject.
898    
899    
900 nigel 31 Version 2.04 18-Feb-99
901     ----------------------
902    
903     1. For parenthesized subpatterns with repeats whose minimum was zero, the
904     computation of the store needed to hold the pattern was incorrect (too large).
905     If such patterns were nested a few deep, this could multiply and become a real
906     problem.
907    
908     2. Added /M option to pcretest to show the memory requirement of a specific
909     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
910    
911     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
912     compiled in such a way that the backtracking after subsequent failure was
913     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
914     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
915    
916    
917 nigel 29 Version 2.03 02-Feb-99
918     ----------------------
919    
920     1. Fixed typo and small mistake in man page.
921    
922 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
923     LICENCE file containing the conditions.
924 nigel 29
925     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
926     Perl, that is the internal \ allows the delimiter to be included in the
927     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
928     the final delimiter, add \ to the end of the pattern (to test the error).
929    
930     4. Added the convenience functions for extracting substrings after a successful
931     match. Updated pcretest to make it able to test these functions.
932    
933    
934 nigel 27 Version 2.02 14-Jan-99
935     ----------------------
936    
937     1. Initialized the working variables associated with each extraction so that
938     their saving and restoring doesn't refer to uninitialized store.
939    
940     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
941     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
942     fix the problem.
943    
944     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
945     calls, and wasn't printing the correct value for compiling calls. Increased the
946     default value of LOOPREPEAT, and the number of significant figures in the
947     times.
948    
949     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
950    
951     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
952     a building problem on Windows NT with a FAT file system.
953    
954    
955 nigel 25 Version 2.01 21-Oct-98
956     ----------------------
957    
958     1. Changed the API for pcre_compile() to allow for the provision of a pointer
959     to character tables built by pcre_maketables() in the current locale. If NULL
960     is passed, the default tables are used.
961    
962    
963 nigel 23 Version 2.00 24-Sep-98
964 nigel 21 ----------------------
965    
966 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
967     it any more.
968    
969     2. Allow quantification of (?>) groups, and make it work correctly.
970    
971     3. The first character computation wasn't working for (?>) groups.
972    
973     4. Correct the implementation of \Z (it is permitted to match on the \n at the
974     end of the subject) and add 5.005's \z, which really does match only at the
975     very end of the subject.
976    
977     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
978    
979     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
980     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
981     localized options. All options to pcre_study() were also removed.
982    
983     7. Add other new features from 5.005:
984    
985     $(?<= positive lookbehind
986     $(?<! negative lookbehind
987     (?imsx-imsx) added the unsetting capability
988     such a setting is global if at outer level; local otherwise
989     (?imsx-imsx:) non-capturing groups with option setting
990     (?(cond)re|re) conditional pattern matching
991    
992     A backreference to itself in a repeated group matches the previous
993     captured string.
994    
995     8. General tidying up of studying (both automatic and via "study")
996     consequential on the addition of new assertions.
997    
998     9. As in 5.005, unlimited repeated groups that could match an empty substring
999     are no longer faulted at compile time. Instead, the loop is forcibly broken at
1000     runtime if any iteration does actually match an empty substring.
1001    
1002     10. Include the RunTest script in the distribution.
1003    
1004     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
1005     discrepancies, some of which were old and were also with respect to 5.004. They
1006     have now been fixed.
1007    
1008    
1009     Version 1.09 28-Apr-98
1010     ----------------------
1011    
1012 nigel 21 1. A negated single character class followed by a quantifier with a minimum
1013     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
1014     program crashes, or just wrong answers. This did not apply to negated classes
1015     containing more than one character, or to minima other than one.
1016    
1017    
1018 nigel 19 Version 1.08 27-Mar-98
1019     ----------------------
1020    
1021     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
1022    
1023     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
1024     latter must appear before anything that relies on it in the pattern.
1025    
1026    
1027 nigel 17 Version 1.07 16-Feb-98
1028     ----------------------
1029    
1030     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
1031     repeat of a potentially empty string).
1032    
1033    
1034 nigel 15 Version 1.06 23-Jan-98
1035     ----------------------
1036    
1037     1. Added Markus Oberhumer's little patches for C++.
1038    
1039     2. Literal strings longer than 255 characters were broken.
1040    
1041    
1042 nigel 13 Version 1.05 23-Dec-97
1043     ----------------------
1044    
1045     1. Negated character classes containing more than one character were failing if
1046     PCRE_CASELESS was set at run time.
1047    
1048    
1049 nigel 11 Version 1.04 19-Dec-97
1050     ----------------------
1051    
1052     1. Corrected the man page, where some "const" qualifiers had been omitted.
1053    
1054     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
1055     input syntax.
1056    
1057     3. Fixed memory leak which occurred when a regex with back references was
1058     matched with an offsets vector that wasn't big enough. The temporary memory
1059     that is used in this case wasn't being freed if the match failed.
1060    
1061     4. Tidied pcretest to ensure it frees memory that it gets.
1062    
1063     5. Temporary memory was being obtained in the case where the passed offsets
1064     vector was exactly big enough.
1065    
1066     6. Corrected definition of offsetof() from change 5 below.
1067    
1068     7. I had screwed up change 6 below and broken the rules for the use of
1069     setjmp(). Now fixed.
1070    
1071    
1072 nigel 9 Version 1.03 18-Dec-97
1073     ----------------------
1074    
1075     1. A erroneous regex with a missing opening parenthesis was correctly
1076     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
1077     on some systems.
1078    
1079     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
1080     it was reported that one broken compiler failed on the former because "code" is
1081     also an independent variable.
1082    
1083     3. The erroneous regex a[]b caused an array overrun reference.
1084    
1085     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
1086     fail on data ending with that character. (It was going on too far, and checking
1087     the next character, typically a binary zero.) This was specific to the
1088     optimized code for single-character negative classes.
1089    
1090     5. Added a contributed patch from the TIN world which does the following:
1091    
1092     + Add an undef for memmove, in case the the system defines a macro for it.
1093    
1094     + Add a definition of offsetof(), in case there isn't one. (I don't know
1095     the reason behind this - offsetof() is part of the ANSI standard - but
1096     it does no harm).
1097    
1098     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
1099     most of the places where whitespace preceded '#'. I have given up and
1100     allowed the remaining 2 cases to be at the margin.
1101    
1102     + Rename some variables in pcre to eliminate shadowing. This seems very
1103     pedantic, but does no harm, of course.
1104    
1105     6. Moved the call to setjmp() into its own function, to get rid of warnings
1106     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
1107    
1108     7. Constructs such as \d{8,} were compiling into the equivalent of
1109 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
1110 nigel 9 outcome, but in this particular case used more store than had been allocated,
1111     which caused the bug to be discovered because it threw up an internal error.
1112    
1113     8. The debugging code in both pcre and pcretest for outputting the compiled
1114     form of a regex was going wrong in the case of back references followed by
1115     curly-bracketed repeats.
1116    
1117    
1118 nigel 7 Version 1.02 12-Dec-97
1119     ----------------------
1120    
1121     1. Typos in pcre.3 and comments in the source fixed.
1122    
1123     2. Applied a contributed patch to get rid of places where it used to remove
1124     'const' from variables, and fixed some signed/unsigned and uninitialized
1125     variable warnings.
1126    
1127     3. Added the "runtest" target to Makefile.
1128    
1129     4. Set default compiler flag to -O2 rather than just -O.
1130    
1131    
1132 nigel 5 Version 1.01 19-Nov-97
1133     ----------------------
1134    
1135     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
1136     like /([ab]*)*/, that is, for classes with more than one character in them.
1137    
1138     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
1139     as /((?>a*))*/ (a PCRE_EXTRA facility).
1140    
1141    
1142     Version 1.00 18-Nov-97
1143     ----------------------
1144    
1145     1. Added compile-time macros to support systems such as SunOS4 which don't have
1146     memmove() or strerror() but have other things that can be used instead.
1147    
1148     2. Arranged that "make clean" removes the executables.
1149    
1150    
1151 nigel 3 Version 0.99 27-Oct-97
1152     ----------------------
1153    
1154     1. Fixed bug in code for optimizing classes with only one character. It was
1155     initializing a 32-byte map regardless, which could cause it to run off the end
1156     of the memory it had got.
1157    
1158     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
1159    
1160    
1161     Version 0.98 22-Oct-97
1162     ----------------------
1163    
1164     1. Fixed bug in code for handling temporary memory usage when there are more
1165     back references than supplied space in the ovector. This could cause segfaults.
1166    
1167    
1168     Version 0.97 21-Oct-97
1169     ----------------------
1170    
1171     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
1172    
1173     2. Optimized negated single characters not to use a bit map.
1174    
1175     3. Brought error texts together as macro definitions; clarified some of them;
1176     fixed one that was wrong - it said "range out of order" when it meant "invalid
1177     escape sequence".
1178    
1179     4. Changed some char * arguments to const char *.
1180    
1181     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
1182    
1183     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
1184     pcretest.
1185    
1186    
1187     Version 0.96 16-Oct-97
1188     ----------------------
1189    
1190     1. Added a simple "pgrep" utility to the distribution.
1191    
1192     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
1193     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
1194     where "ddd" means "one or more decimal digits".
1195    
1196     3. Fixed serious bug. If a pattern had a back reference, but the call to
1197     pcre_exec() didn't supply a large enough ovector to record the related
1198     identifying subpattern, the match always failed. PCRE now remembers the number
1199     of the largest back reference, and gets some temporary memory in which to save
1200     the offsets during matching if necessary, in order to ensure that
1201     backreferences always work.
1202    
1203     4. Increased the compatibility with Perl in a number of ways:
1204    
1205     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
1206     to request this handling. The option can be set at compile or exec time.
1207    
1208     (b) $ matches before a terminating newline by default; an option
1209     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
1210     mode). The option can be set at compile or exec time.
1211    
1212     (c) The handling of \ followed by a digit other than 0 is now supposed to be
1213     the same as Perl's. If the decimal number it represents is less than 10
1214     or there aren't that many previous left capturing parentheses, an octal
1215     escape is read. Inside a character class, it's always an octal escape,
1216     even if it is a single digit.
1217    
1218     (d) An escaped but undefined alphabetic character is taken as a literal,
1219     unless PCRE_EXTRA is set. Currently this just reserves the remaining
1220     escapes.
1221    
1222     (e) {0} is now permitted. (The previous item is removed from the compiled
1223     pattern).
1224    
1225     5. Changed all the names of code files so that the basic parts are no longer
1226     than 10 characters, and abolished the teeny "globals.c" file.
1227    
1228     6. Changed the handling of character classes; they are now done with a 32-byte
1229     bit map always.
1230    
1231     7. Added the -d and /D options to pcretest to make it possible to look at the
1232     internals of compilation without having to recompile pcre.
1233    
1234    
1235     Version 0.95 23-Sep-97
1236     ----------------------
1237    
1238     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
1239     \x20 at the start of a run of normal characters. These were being treated as
1240     real characters, instead of the source characters being re-checked.
1241    
1242    
1243     Version 0.94 18-Sep-97
1244     ----------------------
1245    
1246     1. The functions are now thread-safe, with the caveat that the global variables
1247     containing pointers to malloc() and free() or alternative functions are the
1248     same for all threads.
1249    
1250     2. Get pcre_study() to generate a bitmap of initial characters for non-
1251     anchored patterns when this is possible, and use it if passed to pcre_exec().
1252    
1253    
1254     Version 0.93 15-Sep-97
1255     ----------------------
1256    
1257     1. /(b)|(:+)/ was computing an incorrect first character.
1258    
1259     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
1260     but not actually doing anything yet.
1261    
1262     3. Treat "-" characters in classes that cannot be part of ranges as literals,
1263     as Perl does (e.g. [-az] or [az-]).
1264    
1265     4. Set the anchored flag if a branch starts with .* or .*? because that tests
1266     all possible positions.
1267    
1268     5. Split up into different modules to avoid including unneeded functions in a
1269     compiled binary. However, compile and exec are still in one module. The "study"
1270     function is split off.
1271    
1272     6. The character tables are now in a separate module whose source is generated
1273     by an auxiliary program - but can then be edited by hand if required. There are
1274     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
1275     toupper() in the code.
1276    
1277     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
1278     make them global. Abolish the function for setting them, as the caller can now
1279     set them directly.
1280    
1281    
1282     Version 0.92 11-Sep-97
1283     ----------------------
1284    
1285     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
1286     (e.g. /a{1,3}/) was broken (I mis-optimized it).
1287    
1288     2. Caseless matching was not working in character classes if the characters in
1289     the pattern were in upper case.
1290    
1291     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
1292    
1293     4. Make PCRE_ANCHORED public and accept as a compile option.
1294    
1295     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
1296     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
1297     pass them.
1298    
1299     6. Give an error if bad option bits passed at compile or run time.
1300    
1301     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
1302     pcretest to cause it to pass that flag.
1303    
1304     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
1305     options, and the first character, if set.
1306    
1307     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
1308    
1309    
1310     Version 0.91 10-Sep-97
1311     ----------------------
1312    
1313     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
1314     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
1315    
1316     2. PCRE was looping on encountering an indefinitely repeated back reference to
1317     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
1318     Perl does - treats the match as successful.
1319    
1320     ****

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