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1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 nigel 65 Version 4.1 12-Mar-03
5     ---------------------
6 nigel 63
7 nigel 65 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.
10    
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.
13    
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.
19    
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.
23    
24     5. PCRE was failing to diagnose the case of two named groups with the same
25     name.
26    
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.
34    
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/.
42    
43    
44     Version 4.0 17-Feb-03
45     ---------------------
46    
47 nigel 63 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.
50    
51     2. Moved to autoconf 2.53 and libtool 1.4.2.
52    
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.
56    
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.
61    
62     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
63     space and tab.
64    
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.
67    
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.
74    
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:
79    
80     Pattern PCRE matches Perl matches
81    
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
85    
86     For compatibility with Perl, \Q...\E sequences are recognized inside character
87     classes as well as outside them.
88    
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.
93    
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.
97    
98     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
99     "pcregrep -".
100    
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.
108    
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.
113    
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.
120    
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.
125    
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:]]/).
130    
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.
138    
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.
141    
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/.
144    
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/.
147    
148     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
149     compiling PCRE for use with Virtual Pascal.
150    
151     22. Small fix to the Makefile to make it work properly if the build is done
152     outside the source tree.
153    
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.
157    
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.
162    
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.)
170    
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.
175    
176     27. Fixed typo in error message for invalid (?R item (it said "(?p").
177    
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.]
192    
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:
197    
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
202    
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.
205    
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.
211    
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.
218    
219     33. Internal code re-arrangements:
220    
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.
225    
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.
228    
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.
232    
233     34. Added support for recursive calls to individual subpatterns, along the
234     lines of Robin Houston's patch (but implemented somewhat differently).
235    
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.
239    
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:
246    
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.
250    
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.
255    
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.
259    
260     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
261     calling malloc() with a zero argument.
262    
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.
270    
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).
276    
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.
281    
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:
289    
290     (a) When configuring PCRE before making, you can use --with-match-limit=n
291     to set a default value for the compiled library.
292    
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.
295    
296     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
297    
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:
302    
303     PCRE_CONFIG_UTF8
304    
305     The output is an integer that is set to one if UTF-8 support is available;
306     otherwise it is set to zero.
307    
308     PCRE_CONFIG_NEWLINE
309    
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).
312    
313     PCRE_CONFIG_LINK_SIZE
314    
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.
317    
318     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
319    
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.
322    
323     PCRE_CONFIG_MATCH_LIMIT
324    
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.
327    
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.
331    
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().
338    
339     The pcre_extra structure is now exposed and defined in pcre.h. It currently
340     contains the following fields:
341    
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)
347    
348     The flag bits are also defined in pcre.h, and are
349    
350     PCRE_EXTRA_STUDY_DATA
351     PCRE_EXTRA_MATCH_LIMIT
352     PCRE_EXTRA_CALLOUT_DATA
353    
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.
359    
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.
363    
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.
370    
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.
378    
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.)
383    
384     49. Some changes have been made to the callout feature (see 28 above):
385    
386     (i) A callout function now has three choices for what it returns:
387    
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()
391    
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.
396    
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
404    
405     \C*n pass the number n (may be negative) as callout_data
406    
407     If the callout function in pcretest receives a non-zero value as
408     callout_data, it returns that value.
409    
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).
413    
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.
420    
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.
425    
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.
429    
430     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
431     mode, for example: \x{100}{2,3}.
432    
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.
438    
439     (v) Classes may now contain characters and character ranges with values
440     greater than 255. For example: [ab\x{100}-\x{400}].
441    
442     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
443     PCRE in UTF-8 mode.
444    
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.)
449    
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.
454    
455     54. Added convenience functions for handling named capturing parentheses.
456    
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.
461    
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.
467    
468     57. Updated the building process for Windows DLL, as provided by Fred Cox.
469    
470    
471     Version 3.9 02-Jan-02
472 nigel 61 ---------------------
473    
474     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
475    
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.)
479    
480    
481 nigel 59 Version 3.8 18-Dec-01
482     ---------------------
483    
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?
486    
487    
488 nigel 57 Version 3.7 29-Oct-01
489     ---------------------
490    
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.
494    
495 nigel 59 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.)
499 nigel 57
500 nigel 59
501 nigel 55 Version 3.6 23-Oct-01
502     ---------------------
503    
504     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
505     offsets passed as NULL with zero offset count.
506    
507     2. The config.guess and config.sub files had not been updated when I moved to
508     the latest autoconf.
509    
510    
511 nigel 53 Version 3.5 15-Aug-01
512     ---------------------
513 nigel 5
514 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
515     had been forgotten.
516    
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.
520    
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.
526    
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.
531    
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.
537    
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).
540    
541     7. Upgraded Makefile.in to allow for compiling in a different directory from
542     the source directory.
543    
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.
547    
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.
551    
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().
555    
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.
559    
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.
563    
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.
566    
567    
568 nigel 51 Version 3.4 22-Aug-00
569     ---------------------
570    
571     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
572    
573     2. Diagnose condition (?(0) as an error instead of crashing on matching.
574    
575    
576 nigel 49 Version 3.3 01-Aug-00
577     ---------------------
578    
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.
582    
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.
585    
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.
590    
591     4. Add "make test" as a synonym for "make check". Corrected some comments in
592     the Makefile.
593    
594     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
595     Makefile.
596    
597     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
598     command called pgrep for grepping around the active processes.
599    
600     7. Added the beginnings of support for UTF-8 character strings.
601    
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.)
606    
607    
608 nigel 47 Version 3.2 12-May-00
609     ---------------------
610    
611     This is purely a bug fixing release.
612    
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.
618    
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.
623    
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.
627    
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
630    
631     while ((c = *(++ptr)) != 0 && c != '\n');
632     to
633     while ((c = *(++ptr)) != 0 && c != '\n') ;
634    
635     Totally extraordinary, but if that's what it takes...
636    
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).
641    
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.
645    
646    
647 nigel 45 Version 3.1 09-Feb-00
648     ---------------------
649    
650     The only change in this release is the fixing of some bugs in Makefile.in for
651     the "install" target:
652    
653     (1) It was failing to install pcreposix.h.
654    
655     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
656    
657    
658 nigel 43 Version 3.0 01-Feb-00
659     ---------------------
660 nigel 41
661     1. Add support for the /+ modifier to perltest (to output $` like it does in
662     pcretest).
663    
664     2. Add support for the /g modifier to perltest.
665    
666     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
667     matches null strings.
668    
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.
673    
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.
678    
679 nigel 43 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.
684 nigel 41
685 nigel 43 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.
688    
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.
692    
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.
696    
697     10. Added experimental recursion feature (?R) to handle one common case that
698     Perl 5.6 will be able to do with (?p{...}).
699    
700     11. Added support for POSIX character classes like [:alpha:], which Perl is
701     adopting.
702    
703    
704 nigel 39 Version 2.08 31-Aug-99
705     ----------------------
706    
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.
710    
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.
714    
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.
717    
718     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
719     in GnuWin32 environments.
720    
721    
722 nigel 37 Version 2.07 29-Jul-99
723     ----------------------
724    
725     1. The documentation is now supplied in plain text form and HTML as well as in
726     the form of man page sources.
727    
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.
731    
732     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
733     should be (const char *).
734    
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.
739    
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.
742    
743     6. pgrep -V now gives the PCRE version number and date.
744    
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.
747    
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.
756    
757     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
758     other alternatives are tried instead.
759    
760    
761 nigel 35 Version 2.06 09-Jun-99
762     ----------------------
763    
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.
767    
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.
771    
772     3. Added additional options to pcretest for testing multiple occurrences:
773    
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
777    
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.
782    
783    
784 nigel 33 Version 2.05 21-Apr-99
785     ----------------------
786    
787     1. Changed the type of magic_number from int to long int so that it works
788     properly on 16-bit systems.
789    
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.
796    
797    
798 nigel 31 Version 2.04 18-Feb-99
799     ----------------------
800    
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.
805    
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.
808    
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.
813    
814    
815 nigel 29 Version 2.03 02-Feb-99
816     ----------------------
817    
818     1. Fixed typo and small mistake in man page.
819    
820 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
821     LICENCE file containing the conditions.
822 nigel 29
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).
827    
828     4. Added the convenience functions for extracting substrings after a successful
829     match. Updated pcretest to make it able to test these functions.
830    
831    
832 nigel 27 Version 2.02 14-Jan-99
833     ----------------------
834    
835     1. Initialized the working variables associated with each extraction so that
836     their saving and restoring doesn't refer to uninitialized store.
837    
838     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
839     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
840     fix the problem.
841    
842     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
843     calls, and wasn't printing the correct value for compiling calls. Increased the
844     default value of LOOPREPEAT, and the number of significant figures in the
845     times.
846    
847     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
848    
849     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
850     a building problem on Windows NT with a FAT file system.
851    
852    
853 nigel 25 Version 2.01 21-Oct-98
854     ----------------------
855    
856     1. Changed the API for pcre_compile() to allow for the provision of a pointer
857     to character tables built by pcre_maketables() in the current locale. If NULL
858     is passed, the default tables are used.
859    
860    
861 nigel 23 Version 2.00 24-Sep-98
862 nigel 21 ----------------------
863    
864 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
865     it any more.
866    
867     2. Allow quantification of (?>) groups, and make it work correctly.
868    
869     3. The first character computation wasn't working for (?>) groups.
870    
871     4. Correct the implementation of \Z (it is permitted to match on the \n at the
872     end of the subject) and add 5.005's \z, which really does match only at the
873     very end of the subject.
874    
875     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
876    
877     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
878     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
879     localized options. All options to pcre_study() were also removed.
880    
881     7. Add other new features from 5.005:
882    
883     $(?<= positive lookbehind
884     $(?<! negative lookbehind
885     (?imsx-imsx) added the unsetting capability
886     such a setting is global if at outer level; local otherwise
887     (?imsx-imsx:) non-capturing groups with option setting
888     (?(cond)re|re) conditional pattern matching
889    
890     A backreference to itself in a repeated group matches the previous
891     captured string.
892    
893     8. General tidying up of studying (both automatic and via "study")
894     consequential on the addition of new assertions.
895    
896     9. As in 5.005, unlimited repeated groups that could match an empty substring
897     are no longer faulted at compile time. Instead, the loop is forcibly broken at
898     runtime if any iteration does actually match an empty substring.
899    
900     10. Include the RunTest script in the distribution.
901    
902     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
903     discrepancies, some of which were old and were also with respect to 5.004. They
904     have now been fixed.
905    
906    
907     Version 1.09 28-Apr-98
908     ----------------------
909    
910 nigel 21 1. A negated single character class followed by a quantifier with a minimum
911     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
912     program crashes, or just wrong answers. This did not apply to negated classes
913     containing more than one character, or to minima other than one.
914    
915    
916 nigel 19 Version 1.08 27-Mar-98
917     ----------------------
918    
919     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
920    
921     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
922     latter must appear before anything that relies on it in the pattern.
923    
924    
925 nigel 17 Version 1.07 16-Feb-98
926     ----------------------
927    
928     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
929     repeat of a potentially empty string).
930    
931    
932 nigel 15 Version 1.06 23-Jan-98
933     ----------------------
934    
935     1. Added Markus Oberhumer's little patches for C++.
936    
937     2. Literal strings longer than 255 characters were broken.
938    
939    
940 nigel 13 Version 1.05 23-Dec-97
941     ----------------------
942    
943     1. Negated character classes containing more than one character were failing if
944     PCRE_CASELESS was set at run time.
945    
946    
947 nigel 11 Version 1.04 19-Dec-97
948     ----------------------
949    
950     1. Corrected the man page, where some "const" qualifiers had been omitted.
951    
952     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
953     input syntax.
954    
955     3. Fixed memory leak which occurred when a regex with back references was
956     matched with an offsets vector that wasn't big enough. The temporary memory
957     that is used in this case wasn't being freed if the match failed.
958    
959     4. Tidied pcretest to ensure it frees memory that it gets.
960    
961     5. Temporary memory was being obtained in the case where the passed offsets
962     vector was exactly big enough.
963    
964     6. Corrected definition of offsetof() from change 5 below.
965    
966     7. I had screwed up change 6 below and broken the rules for the use of
967     setjmp(). Now fixed.
968    
969    
970 nigel 9 Version 1.03 18-Dec-97
971     ----------------------
972    
973     1. A erroneous regex with a missing opening parenthesis was correctly
974     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
975     on some systems.
976    
977     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
978     it was reported that one broken compiler failed on the former because "code" is
979     also an independent variable.
980    
981     3. The erroneous regex a[]b caused an array overrun reference.
982    
983     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
984     fail on data ending with that character. (It was going on too far, and checking
985     the next character, typically a binary zero.) This was specific to the
986     optimized code for single-character negative classes.
987    
988     5. Added a contributed patch from the TIN world which does the following:
989    
990     + Add an undef for memmove, in case the the system defines a macro for it.
991    
992     + Add a definition of offsetof(), in case there isn't one. (I don't know
993     the reason behind this - offsetof() is part of the ANSI standard - but
994     it does no harm).
995    
996     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
997     most of the places where whitespace preceded '#'. I have given up and
998     allowed the remaining 2 cases to be at the margin.
999    
1000     + Rename some variables in pcre to eliminate shadowing. This seems very
1001     pedantic, but does no harm, of course.
1002    
1003     6. Moved the call to setjmp() into its own function, to get rid of warnings
1004     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
1005    
1006     7. Constructs such as \d{8,} were compiling into the equivalent of
1007 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
1008 nigel 9 outcome, but in this particular case used more store than had been allocated,
1009     which caused the bug to be discovered because it threw up an internal error.
1010    
1011     8. The debugging code in both pcre and pcretest for outputting the compiled
1012     form of a regex was going wrong in the case of back references followed by
1013     curly-bracketed repeats.
1014    
1015    
1016 nigel 7 Version 1.02 12-Dec-97
1017     ----------------------
1018    
1019     1. Typos in pcre.3 and comments in the source fixed.
1020    
1021     2. Applied a contributed patch to get rid of places where it used to remove
1022     'const' from variables, and fixed some signed/unsigned and uninitialized
1023     variable warnings.
1024    
1025     3. Added the "runtest" target to Makefile.
1026    
1027     4. Set default compiler flag to -O2 rather than just -O.
1028    
1029    
1030 nigel 5 Version 1.01 19-Nov-97
1031     ----------------------
1032    
1033     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
1034     like /([ab]*)*/, that is, for classes with more than one character in them.
1035    
1036     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
1037     as /((?>a*))*/ (a PCRE_EXTRA facility).
1038    
1039    
1040     Version 1.00 18-Nov-97
1041     ----------------------
1042    
1043     1. Added compile-time macros to support systems such as SunOS4 which don't have
1044     memmove() or strerror() but have other things that can be used instead.
1045    
1046     2. Arranged that "make clean" removes the executables.
1047    
1048    
1049 nigel 3 Version 0.99 27-Oct-97
1050     ----------------------
1051    
1052     1. Fixed bug in code for optimizing classes with only one character. It was
1053     initializing a 32-byte map regardless, which could cause it to run off the end
1054     of the memory it had got.
1055    
1056     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
1057    
1058    
1059     Version 0.98 22-Oct-97
1060     ----------------------
1061    
1062     1. Fixed bug in code for handling temporary memory usage when there are more
1063     back references than supplied space in the ovector. This could cause segfaults.
1064    
1065    
1066     Version 0.97 21-Oct-97
1067     ----------------------
1068    
1069     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
1070    
1071     2. Optimized negated single characters not to use a bit map.
1072    
1073     3. Brought error texts together as macro definitions; clarified some of them;
1074     fixed one that was wrong - it said "range out of order" when it meant "invalid
1075     escape sequence".
1076    
1077     4. Changed some char * arguments to const char *.
1078    
1079     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
1080    
1081     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
1082     pcretest.
1083    
1084    
1085     Version 0.96 16-Oct-97
1086     ----------------------
1087    
1088     1. Added a simple "pgrep" utility to the distribution.
1089    
1090     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
1091     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
1092     where "ddd" means "one or more decimal digits".
1093    
1094     3. Fixed serious bug. If a pattern had a back reference, but the call to
1095     pcre_exec() didn't supply a large enough ovector to record the related
1096     identifying subpattern, the match always failed. PCRE now remembers the number
1097     of the largest back reference, and gets some temporary memory in which to save
1098     the offsets during matching if necessary, in order to ensure that
1099     backreferences always work.
1100    
1101     4. Increased the compatibility with Perl in a number of ways:
1102    
1103     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
1104     to request this handling. The option can be set at compile or exec time.
1105    
1106     (b) $ matches before a terminating newline by default; an option
1107     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
1108     mode). The option can be set at compile or exec time.
1109    
1110     (c) The handling of \ followed by a digit other than 0 is now supposed to be
1111     the same as Perl's. If the decimal number it represents is less than 10
1112     or there aren't that many previous left capturing parentheses, an octal
1113     escape is read. Inside a character class, it's always an octal escape,
1114     even if it is a single digit.
1115    
1116     (d) An escaped but undefined alphabetic character is taken as a literal,
1117     unless PCRE_EXTRA is set. Currently this just reserves the remaining
1118     escapes.
1119    
1120     (e) {0} is now permitted. (The previous item is removed from the compiled
1121     pattern).
1122    
1123     5. Changed all the names of code files so that the basic parts are no longer
1124     than 10 characters, and abolished the teeny "globals.c" file.
1125    
1126     6. Changed the handling of character classes; they are now done with a 32-byte
1127     bit map always.
1128    
1129     7. Added the -d and /D options to pcretest to make it possible to look at the
1130     internals of compilation without having to recompile pcre.
1131    
1132    
1133     Version 0.95 23-Sep-97
1134     ----------------------
1135    
1136     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
1137     \x20 at the start of a run of normal characters. These were being treated as
1138     real characters, instead of the source characters being re-checked.
1139    
1140    
1141     Version 0.94 18-Sep-97
1142     ----------------------
1143    
1144     1. The functions are now thread-safe, with the caveat that the global variables
1145     containing pointers to malloc() and free() or alternative functions are the
1146     same for all threads.
1147    
1148     2. Get pcre_study() to generate a bitmap of initial characters for non-
1149     anchored patterns when this is possible, and use it if passed to pcre_exec().
1150    
1151    
1152     Version 0.93 15-Sep-97
1153     ----------------------
1154    
1155     1. /(b)|(:+)/ was computing an incorrect first character.
1156    
1157     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
1158     but not actually doing anything yet.
1159    
1160     3. Treat "-" characters in classes that cannot be part of ranges as literals,
1161     as Perl does (e.g. [-az] or [az-]).
1162    
1163     4. Set the anchored flag if a branch starts with .* or .*? because that tests
1164     all possible positions.
1165    
1166     5. Split up into different modules to avoid including unneeded functions in a
1167     compiled binary. However, compile and exec are still in one module. The "study"
1168     function is split off.
1169    
1170     6. The character tables are now in a separate module whose source is generated
1171     by an auxiliary program - but can then be edited by hand if required. There are
1172     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
1173     toupper() in the code.
1174    
1175     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
1176     make them global. Abolish the function for setting them, as the caller can now
1177     set them directly.
1178    
1179    
1180     Version 0.92 11-Sep-97
1181     ----------------------
1182    
1183     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
1184     (e.g. /a{1,3}/) was broken (I mis-optimized it).
1185    
1186     2. Caseless matching was not working in character classes if the characters in
1187     the pattern were in upper case.
1188    
1189     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
1190    
1191     4. Make PCRE_ANCHORED public and accept as a compile option.
1192    
1193     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
1194     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
1195     pass them.
1196    
1197     6. Give an error if bad option bits passed at compile or run time.
1198    
1199     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
1200     pcretest to cause it to pass that flag.
1201    
1202     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
1203     options, and the first character, if set.
1204    
1205     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
1206    
1207    
1208     Version 0.91 10-Sep-97
1209     ----------------------
1210    
1211     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
1212     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
1213    
1214     2. PCRE was looping on encountering an indefinitely repeated back reference to
1215     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
1216     Perl does - treats the match as successful.
1217    
1218     ****

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