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1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 nigel 71 Version 4.4 13-Aug-03
5     ---------------------
6    
7     1. In UTF-8 mode, a character class containing characters with values between
8     127 and 255 was not handled correctly if the compiled pattern was studied.
9     In fixing this, I have also improved the studying algorithm for such
10     classes (slightly).
11    
12     2. Three internal functions had redundant arguments passed to them. Removal
13     might give a very teeny performance improvement.
14    
15     3. Documentation bug: the value of the capture_top field in a callout is *one
16     more than* the number of the hightest numbered captured substring.
17    
18     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
19     in incorrectly linking with a previously installed version. They now link
20     explicitly with libpcre.la.
21    
22     5. configure.in no longer needs to recognize Cygwin specially.
23    
24     6. A problem in pcre.in for Windows platforms is fixed.
25    
26     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
27     pcretest, it used to include the size of the study block as part of its
28     output. Unfortunately, the structure contains a field that has a different
29     size on different hardware architectures. This meant that the tests that
30     showed this size failed. As the block is currently always of a fixed size,
31     this information isn't actually particularly useful in pcretest output, so
32     I have just removed it.
33    
34     8. Three pre-processor statements accidentally did not start in column 1.
35     Sadly, there are *still* compilers around that complain, even though
36     standard C has not required this for well over a decade. Sigh.
37    
38     9. In pcretest, the code for checking callouts passed small integers in the
39     callout_data field, which is a void * field. However, some picky compilers
40     complained about the casts involved for this on 64-bit systems. Now
41     pcretest passes the address of the small integer instead, which should get
42     rid of the warnings.
43    
44     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
45     both compile and run time, and gives an error if an invalid UTF-8 sequence
46     is found. There is a option for disabling this check in cases where the
47     string is known to be correct and/or the maximum performance is wanted.
48    
49     11. In response to a bug report, I changed one line in Makefile.in from
50    
51     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
52     to
53     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
54    
55     to look similar to other lines, but I have no way of telling whether this
56     is the right thing to do, as I do not use Windows. No doubt I'll get told
57     if it's wrong...
58    
59    
60 nigel 69 Version 4.3 21-May-03
61     ---------------------
62    
63     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
64     Makefile.
65    
66     2. Some refactoring to improve the quality of the code:
67    
68     (i) The utf8_table... variables are now declared "const".
69    
70     (ii) The code for \cx, which used the "case flipping" table to upper case
71     lower case letters, now just substracts 32. This is ASCII-specific,
72     but the whole concept of \cx is ASCII-specific, so it seems
73     reasonable.
74    
75     (iii) PCRE was using its character types table to recognize decimal and
76     hexadecimal digits in the pattern. This is silly, because it handles
77     only 0-9, a-f, and A-F, but the character types table is locale-
78     specific, which means strange things might happen. A private
79     table is now used for this - though it costs 256 bytes, a table is
80     much faster than multiple explicit tests. Of course, the standard
81     character types table is still used for matching digits in subject
82     strings against \d.
83    
84     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
85     ending in _t are). So I've renamed it as ESC_tee.
86    
87     3. The first argument for regexec() in the POSIX wrapper should have been
88     defined as "const".
89    
90     4. Changed pcretest to use malloc() for its buffers so that they can be
91     Electric Fenced for debugging.
92    
93     5. There were several places in the code where, in UTF-8 mode, PCRE would try
94     to read one or more bytes before the start of the subject string. Often this
95     had no effect on PCRE's behaviour, but in some circumstances it could
96     provoke a segmentation fault.
97    
98     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
99     to try to read one or more bytes before the start of the subject string.
100    
101     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
102     UTF-8 support could misbehave in various ways if the subject string
103     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
104     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
105     back over UTF-8 characters.)
106    
107    
108 nigel 67 Version 4.2 14-Apr-03
109     ---------------------
110    
111     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
112    
113     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
114     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
115     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
116     [WIN_PREFIX]: new variable, "cyg" for Cygwin
117     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
118     and BUILD_EXEEXT
119     Note: automatic setting of the BUILD variables is not yet working
120     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
121     compile-time but not at link-time
122     [LINK]: use for linking executables only
123     make different versions for Windows and non-Windows
124     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
125     libraries
126     [LINK_FOR_BUILD]: new variable
127     [OBJEXT]: use throughout
128     [EXEEXT]: use throughout
129     <winshared>: new target
130     <wininstall>: new target
131     <dftables.o>: use native compiler
132     <dftables>: use native linker
133     <install>: handle Windows platform correctly
134     <clean>: ditto
135     <check>: ditto
136     copy DLL to top builddir before testing
137    
138     As part of these changes, -no-undefined was removed again. This was reported
139     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
140     in any case.
141    
142     3. Some tidies to get rid of compiler warnings:
143    
144     . In the match_data structure, match_limit was an unsigned long int, whereas
145     match_call_count was an int. I've made them both unsigned long ints.
146    
147     . In pcretest the fact that a const uschar * doesn't automatically cast to
148     a void * provoked a warning.
149    
150     . Turning on some more compiler warnings threw up some "shadow" variables
151     and a few more missing casts.
152    
153     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
154     option, a class that contained a single character with a value between 128
155     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
156    
157     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
158     option, a class that contained several characters, but with at least one
159     whose value was between 128 and 255 caused PCRE to crash.
160    
161    
162 nigel 65 Version 4.1 12-Mar-03
163     ---------------------
164 nigel 63
165 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
166     needed, and a string in dftables.c that was longer than standard compilers are
167     required to support.
168    
169     2. Compiling with Sun's compiler found a few more places where the code could
170     be tidied up in order to avoid warnings.
171    
172     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
173     first of these names is deprecated in the latest Autoconf in favour of the name
174     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
175     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
176     analogy I have changed it to CFLAGS_FOR_BUILD.
177    
178     4. Added -no-undefined to the linking command in the Makefile, because this is
179     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
180     linking step for the pcreposix library.
181    
182     5. PCRE was failing to diagnose the case of two named groups with the same
183     name.
184    
185     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
186     literal character that is needed in the subject for a match, and scans along to
187     ensure that it is present before embarking on the full matching process. This
188     saves time in cases of nested unlimited repeats that are never going to match.
189     Problem: the scan can take a lot of time if the subject is very long (e.g.
190     megabytes), thus penalizing straightforward matches. It is now done only if the
191     amount of subject to be scanned is less than 1000 bytes.
192    
193     7. A lesser problem with the same optimization is that it was recording the
194     first character of an anchored pattern as "needed", thus provoking a search
195     right along the subject, even when the first match of the pattern was going to
196     fail. The "needed" character is now not set for anchored patterns, unless it
197     follows something in the pattern that is of non-fixed length. Thus, it still
198     fulfils its original purpose of finding quick non-matches in cases of nested
199     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
200    
201    
202     Version 4.0 17-Feb-03
203     ---------------------
204    
205 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
206     extended to the end of string, PCRE compiled incorrect data. This could lead to
207     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
208    
209     2. Moved to autoconf 2.53 and libtool 1.4.2.
210    
211     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
212     the special perltest8 script is no longer needed - all the tests can be run
213     from a single perltest script.
214    
215     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
216     by \s. It has now been removed in PCRE. This means it isn't recognized as
217     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
218     class [:space:] *does* include VT, thereby creating a mess.
219    
220     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
221     space and tab.
222    
223     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
224     its new features into the main test script, reducing the number of scripts.
225    
226     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
227     were backward compatible, and made the (?i) apply to the whole pattern, as if
228     /i were given. Now it behaves more logically, and applies the option setting
229     only to what follows. PCRE has been changed to follow suit. However, if it
230     finds options settings right at the start of the pattern, it extracts them into
231     the global options, as before. Thus, they show up in the info data.
232    
233     8. Added support for the \Q...\E escape sequence. Characters in between are
234     treated as literals. This is slightly different from Perl in that $ and @ are
235     also handled as literals inside the quotes. In Perl, they will cause variable
236     interpolation. Note the following examples:
237    
238     Pattern PCRE matches Perl matches
239    
240     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
241     \Qabc\$xyz\E abc\$xyz abc\$xyz
242     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
243    
244     For compatibility with Perl, \Q...\E sequences are recognized inside character
245     classes as well as outside them.
246    
247     9. Re-organized 3 code statements in pcretest to avoid "overflow in
248     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
249     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
250     signed/unsigned warnings.
251    
252     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
253     option for pcretest, so I've replaced it by a simple function that does just
254     that job.
255    
256     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
257     "pcregrep -".
258    
259     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
260     Java package. This provides some syntactic sugar for simple cases of what my
261     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
262     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
263     item, you can use this simplified notation. Note that only makes sense with
264     greedy quantifiers. Consequently, the use of the possessive quantifier forces
265     greediness, whatever the setting of the PCRE_UNGREEDY option.
266    
267     13. A change of greediness default within a pattern was not taking effect at
268     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
269     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
270     was abstracted outside.
271    
272     14. PCRE now supports the \G assertion. It is true when the current matching
273     position is at the start point of the match. This differs from \A when the
274     starting offset is non-zero. Used with the /g option of pcretest (or similar
275     code), it works in the same way as it does for Perl's /g option. If all
276     alternatives of a regex begin with \G, the expression is anchored to the start
277     match position, and the "anchored" flag is set in the compiled expression.
278    
279     15. Some bugs concerning the handling of certain option changes within patterns
280     have been fixed. These applied to options other than (?ims). For example,
281     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
282     been the other way round. Some of this was related to change 7 above.
283    
284     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
285     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
286     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
287     POSIX classes only within a class (e.g. /[[:alpha:]]/).
288    
289     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
290     mode. Unlike ".", it always matches newline, whatever the setting of
291     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
292     assertions. Perl allows it, but it doesn't (in general) work because it can't
293     calculate the length of the lookbehind. At least, that's the case for Perl
294     5.8.0 - I've been told they are going to document that it doesn't work in
295     future.
296    
297     18. Added an error diagnosis for escapes that PCRE does not support: these are
298     \L, \l, \N, \P, \p, \U, \u, and \X.
299    
300     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
301     reading past the end of the pattern in cases such as /[abcd/.
302    
303     20. PCRE was getting more memory than necessary for patterns with classes that
304     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
305    
306     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
307     compiling PCRE for use with Virtual Pascal.
308    
309     22. Small fix to the Makefile to make it work properly if the build is done
310     outside the source tree.
311    
312     23. Added a new extension: a condition to go with recursion. If a conditional
313     subpattern starts with (?(R) the "true" branch is used if recursion has
314     happened, whereas the "false" branch is used only at the top level.
315    
316     24. When there was a very long string of literal characters (over 255 bytes
317     without UTF support, over 250 bytes with UTF support), the computation of how
318     much memory was required could be incorrect, leading to segfaults or other
319     strange effects.
320    
321     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
322     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
323     there was a subsequent back reference to those brackets. This meant that, for
324     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
325     possible to check for precisely this case. All we can do is abandon the
326     optimization if .* occurs inside capturing brackets when there are any back
327     references whatsoever. (See below for a better fix that came later.)
328    
329     26. The handling of the optimization for finding the first character of a
330     non-anchored pattern, and for finding a character that is required later in the
331     match were failing in some cases. This didn't break the matching; it just
332     failed to optimize when it could. The way this is done has been re-implemented.
333    
334     27. Fixed typo in error message for invalid (?R item (it said "(?p").
335    
336     28. Added a new feature that provides some of the functionality that Perl
337     provides with (?{...}). The facility is termed a "callout". The way it is done
338     in PCRE is for the caller to provide an optional function, by setting
339     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
340     global variable. By default it is unset, which disables all calling out. To get
341     the function called, the regex must include (?C) at appropriate points. This
342     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
343     This provides a means of identifying different callout points. When PCRE
344     reaches such a point in the regex, if pcre_callout has been set, the external
345     function is called. It is provided with data in a structure called
346     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
347     matching continues; if it returns a non-zero value, the match at the current
348     point fails. However, backtracking will occur if possible. [This was changed
349     later and other features added - see item 49 below.]
350    
351     29. pcretest is upgraded to test the callout functionality. It provides a
352     callout function that displays information. By default, it shows the start of
353     the match and the current position in the text. There are some new data escapes
354     to vary what happens:
355    
356     \C+ in addition, show current contents of captured substrings
357     \C- do not supply a callout function
358     \C!n return 1 when callout number n is reached
359     \C!n!m return 1 when callout number n is reached for the mth time
360    
361     30. If pcregrep was called with the -l option and just a single file name, it
362     output "<stdin>" if a match was found, instead of the file name.
363    
364     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
365     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
366     pcre_exec(). This saves a malloc/free per call. The default value of
367     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
368     when configuring.
369    
370     32. The default maximum size of a compiled pattern is 64K. There have been a
371     few cases of people hitting this limit. The code now uses macros to handle the
372     storing of links as offsets within the compiled pattern. It defaults to 2-byte
373     links, but this can be changed to 3 or 4 bytes by --with-link-size when
374     configuring. Tests 2 and 5 work only with 2-byte links because they output
375     debugging information about compiled patterns.
376    
377     33. Internal code re-arrangements:
378    
379     (a) Moved the debugging function for printing out a compiled regex into
380     its own source file (printint.c) and used #include to pull it into
381     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
382     separate copies.
383    
384     (b) Defined the list of op-code names for debugging as a macro in
385     internal.h so that it is next to the definition of the opcodes.
386    
387     (c) Defined a table of op-code lengths for simpler skipping along compiled
388     code. This is again a macro in internal.h so that it is next to the
389     definition of the opcodes.
390    
391     34. Added support for recursive calls to individual subpatterns, along the
392     lines of Robin Houston's patch (but implemented somewhat differently).
393    
394     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
395     allow it to read and process whole directories in Win32. This code was
396     contributed by Lionel Fourquaux; it has not been tested by me.
397    
398     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
399     used to name a group. Names consist of alphanumerics and underscores, and must
400     be unique. Back references use the syntax (?P=name) and recursive calls use
401     (?P>name) which is a PCRE extension to the Python extension. Groups still have
402     numbers. The function pcre_fullinfo() can be used after compilation to extract
403     a name/number map. There are three relevant calls:
404    
405     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
406     PCRE_INFO_NAMECOUNT yields the number of entries
407     PCRE_INFO_NAMETABLE yields a pointer to the map.
408    
409     The map is a vector of fixed-size entries. The size of each entry depends on
410     the length of the longest name used. The first two bytes of each entry are the
411     group number, most significant byte first. There follows the corresponding
412     name, zero terminated. The names are in alphabetical order.
413    
414     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
415     case instead of 255. Making it the same both with and without UTF-8 support
416     means that the same test output works with both.
417    
418     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
419     calling malloc() with a zero argument.
420    
421     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
422     optimization. I've improved things by keeping a bitmap of backreferences with
423     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
424     fact referenced, the optimization can be applied. It is unlikely that a
425     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
426     the match to follow \n) will appear inside brackets with a number greater than
427     31, but if it does, any back reference > 31 suppresses the optimization.
428    
429     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
430     of disabling numbered capturing parentheses. Any opening parenthesis that is
431     not followed by ? behaves as if it were followed by ?: but named parentheses
432     can still be used for capturing (and they will acquire numbers in the usual
433     way).
434    
435     41. Redesigned the return codes from the match() function into yes/no/error so
436     that errors can be passed back from deep inside the nested calls. A malloc
437     failure while inside a recursive subpattern call now causes the
438     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
439    
440     42. It is now possible to set a limit on the number of times the match()
441     function is called in a call to pcre_exec(). This facility makes it possible to
442     limit the amount of recursion and backtracking, though not in a directly
443     obvious way, because the match() function is used in a number of different
444     circumstances. The count starts from zero for each position in the subject
445     string (for non-anchored patterns). The default limit is, for compatibility, a
446     large number, namely 10 000 000. You can change this in two ways:
447    
448     (a) When configuring PCRE before making, you can use --with-match-limit=n
449     to set a default value for the compiled library.
450    
451     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
452     a different value is set. See 45 below.
453    
454     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
455    
456     43. Added a new function pcre_config(int, void *) to enable run-time extraction
457     of things that can be changed at compile time. The first argument specifies
458     what is wanted and the second points to where the information is to be placed.
459     The current list of available information is:
460    
461     PCRE_CONFIG_UTF8
462    
463     The output is an integer that is set to one if UTF-8 support is available;
464     otherwise it is set to zero.
465    
466     PCRE_CONFIG_NEWLINE
467    
468     The output is an integer that it set to the value of the code that is used for
469     newline. It is either LF (10) or CR (13).
470    
471     PCRE_CONFIG_LINK_SIZE
472    
473     The output is an integer that contains the number of bytes used for internal
474     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
475    
476     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
477    
478     The output is an integer that contains the threshold above which the POSIX
479     interface uses malloc() for output vectors. See item 31 above.
480    
481     PCRE_CONFIG_MATCH_LIMIT
482    
483     The output is an unsigned integer that contains the default limit of the number
484     of match() calls in a pcre_exec() execution. See 42 above.
485    
486     44. pcretest has been upgraded by the addition of the -C option. This causes it
487     to extract all the available output from the new pcre_config() function, and to
488     output it. The program then exits immediately.
489    
490     45. A need has arisen to pass over additional data with calls to pcre_exec() in
491     order to support additional features. One way would have been to define
492     pcre_exec2() (for example) with extra arguments, but this would not have been
493     extensible, and would also have required all calls to the original function to
494     be mapped to the new one. Instead, I have chosen to extend the mechanism that
495     is used for passing in "extra" data from pcre_study().
496    
497     The pcre_extra structure is now exposed and defined in pcre.h. It currently
498     contains the following fields:
499    
500     flags a bitmap indicating which of the following fields are set
501     study_data opaque data from pcre_study()
502     match_limit a way of specifying a limit on match() calls for a specific
503     call to pcre_exec()
504     callout_data data for callouts (see 49 below)
505    
506     The flag bits are also defined in pcre.h, and are
507    
508     PCRE_EXTRA_STUDY_DATA
509     PCRE_EXTRA_MATCH_LIMIT
510     PCRE_EXTRA_CALLOUT_DATA
511    
512     The pcre_study() function now returns one of these new pcre_extra blocks, with
513     the actual study data pointed to by the study_data field, and the
514     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
515     before. That is, this change is entirely upwards-compatible and requires no
516     change to existing code.
517    
518     If you want to pass in additional data to pcre_exec(), you can either place it
519     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
520     block.
521    
522     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
523     data string contains the escape sequence \M, pcretest calls pcre_exec() several
524     times with different match limits, until it finds the minimum value needed for
525     pcre_exec() to complete. The value is then output. This can be instructive; for
526     most simple matches the number is quite small, but for pathological cases it
527     gets very large very quickly.
528    
529     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
530     returns the size of the data block pointed to by the study_data field in a
531     pcre_extra block, that is, the value that was passed as the argument to
532     pcre_malloc() when PCRE was getting memory in which to place the information
533     created by pcre_study(). The fourth argument should point to a size_t variable.
534     pcretest has been extended so that this information is shown after a successful
535     pcre_study() call when information about the compiled regex is being displayed.
536    
537     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
538     because what follows is always an absolute path. (Later: it turns out that this
539     is more than cosmetic for MinGW, because it doesn't like empty path
540     components.)
541    
542     49. Some changes have been made to the callout feature (see 28 above):
543    
544     (i) A callout function now has three choices for what it returns:
545    
546     0 => success, carry on matching
547     > 0 => failure at this point, but backtrack if possible
548     < 0 => serious error, return this value from pcre_exec()
549    
550     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
551     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
552     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
553     use by callout functions. It will never be used by PCRE itself.
554    
555     (ii) The pcre_extra structure (see 45 above) has a void * field called
556     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
557     pcre_callout_block structure has a field of the same name. The contents of
558     the field passed in the pcre_extra structure are passed to the callout
559     function in the corresponding field in the callout block. This makes it
560     easier to use the same callout-containing regex from multiple threads. For
561     testing, the pcretest program has a new data escape
562    
563     \C*n pass the number n (may be negative) as callout_data
564    
565     If the callout function in pcretest receives a non-zero value as
566     callout_data, it returns that value.
567    
568     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
569     there were some redundant $(CFLAGS) in commands that are now specified as
570     $(LINK), which already includes $(CFLAGS).
571    
572     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
573     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
574     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
575     one-byte characters throughout. Note that case-insensitive matching applies
576     only to characters whose values are less than 256. PCRE doesn't support the
577     notion of cases for higher-valued characters.
578    
579     (i) A character class whose characters are all within 0-255 is handled as
580     a bit map, and the map is inverted for negative classes. Previously, a
581     character > 255 always failed to match such a class; however it should
582     match if the class was a negative one (e.g. [^ab]). This has been fixed.
583    
584     (ii) A negated character class with a single character < 255 is coded as
585     "not this character" (OP_NOT). This wasn't working properly when the test
586     character was multibyte, either singly or repeated.
587    
588     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
589     mode, for example: \x{100}{2,3}.
590    
591     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
592     singly or repeated) now correctly test multibyte characters. However,
593     PCRE doesn't recognize any characters with values greater than 255 as
594     digits, spaces, or word characters. Such characters always match \D, \S,
595     and \W, and never match \d, \s, or \w.
596    
597     (v) Classes may now contain characters and character ranges with values
598     greater than 255. For example: [ab\x{100}-\x{400}].
599    
600     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
601     PCRE in UTF-8 mode.
602    
603     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
604     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
605     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
606     value.)
607    
608     53. The single man page has become too large. I have therefore split it up into
609     a number of separate man pages. These also give rise to individual HTML pages;
610     these are now put in a separate directory, and there is an index.html page that
611     lists them all. Some hyperlinking between the pages has been installed.
612    
613     54. Added convenience functions for handling named capturing parentheses.
614    
615     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
616     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
617     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
618     are faulted.
619    
620     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
621     calling configure. These values are used when compiling the dftables.c program
622     which is run to generate the source of the default character tables. They
623     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
624     you will need to set these values.
625    
626     57. Updated the building process for Windows DLL, as provided by Fred Cox.
627    
628    
629     Version 3.9 02-Jan-02
630 nigel 61 ---------------------
631    
632     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
633    
634     2. If --disable-static was given, the building process failed when trying to
635     build pcretest and pcregrep. (For some reason it was using libtool to compile
636     them, which is not right, as they aren't part of the library.)
637    
638    
639 nigel 59 Version 3.8 18-Dec-01
640     ---------------------
641    
642     1. The experimental UTF-8 code was completely screwed up. It was packing the
643     bytes in the wrong order. How dumb can you get?
644    
645    
646 nigel 57 Version 3.7 29-Oct-01
647     ---------------------
648    
649     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
650     This caused pcretest, when used on the test data, to segfault. Unfortunately,
651     this didn't happen under Solaris 8, where I normally test things.
652    
653 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
654     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
655     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
656     this fix an hour or so after the initial 3.7 release.)
657 nigel 57
658 nigel 59
659 nigel 55 Version 3.6 23-Oct-01
660     ---------------------
661    
662     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
663     offsets passed as NULL with zero offset count.
664    
665     2. The config.guess and config.sub files had not been updated when I moved to
666     the latest autoconf.
667    
668    
669 nigel 53 Version 3.5 15-Aug-01
670     ---------------------
671 nigel 5
672 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
673     had been forgotten.
674    
675     2. By using declared but undefined structures, we can avoid using "void"
676     definitions in pcre.h while keeping the internal definitions of the structures
677     private.
678    
679     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
680     user point of view, this means that both static and shared libraries are built
681     by default, but this can be individually controlled. More of the work of
682     handling this static/shared cases is now inside libtool instead of PCRE's make
683     file.
684    
685     4. The pcretest utility is now installed along with pcregrep because it is
686     useful for users (to test regexs) and by doing this, it automatically gets
687     relinked by libtool. The documentation has been turned into a man page, so
688     there are now .1, .txt, and .html versions in /doc.
689    
690     5. Upgrades to pcregrep:
691     (i) Added long-form option names like gnu grep.
692     (ii) Added --help to list all options with an explanatory phrase.
693     (iii) Added -r, --recursive to recurse into sub-directories.
694     (iv) Added -f, --file to read patterns from a file.
695    
696     6. pcre_exec() was referring to its "code" argument before testing that
697     argument for NULL (and giving an error if it was NULL).
698    
699     7. Upgraded Makefile.in to allow for compiling in a different directory from
700     the source directory.
701    
702     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
703     options bits, the pointer it was passed was to an int instead of to an unsigned
704     long int. This mattered only on 64-bit systems.
705    
706     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
707     generated) instead of pcre.in, which it its source. Also made the same change
708     in several of the .c files.
709    
710     10. A new release of gcc defines printf() as a macro, which broke pcretest
711     because it had an ifdef in the middle of a string argument for printf(). Fixed
712     by using separate calls to printf().
713    
714     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
715     script, to force use of CR or LF instead of \n in the source. On non-Unix
716     systems, the value can be set in config.h.
717    
718     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
719     absolute limit. Changed the text of the error message to make this clear, and
720     likewise updated the man page.
721    
722     13. The limit of 99 on the number of capturing subpatterns has been removed.
723     The new limit is 65535, which I hope will not be a "real" limit.
724    
725    
726 nigel 51 Version 3.4 22-Aug-00
727     ---------------------
728    
729     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
730    
731     2. Diagnose condition (?(0) as an error instead of crashing on matching.
732    
733    
734 nigel 49 Version 3.3 01-Aug-00
735     ---------------------
736    
737     1. If an octal character was given, but the value was greater than \377, it
738     was not getting masked to the least significant bits, as documented. This could
739     lead to crashes in some systems.
740    
741     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
742     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
743    
744     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
745     These just pass their arguments on to (pcre_free)(), but they are provided
746     because some uses of PCRE bind it to non-C systems that can call its functions,
747     but cannot call free() or pcre_free() directly.
748    
749     4. Add "make test" as a synonym for "make check". Corrected some comments in
750     the Makefile.
751    
752     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
753     Makefile.
754    
755     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
756     command called pgrep for grepping around the active processes.
757    
758     7. Added the beginnings of support for UTF-8 character strings.
759    
760     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
761     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
762     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
763     out for the ar command.)
764    
765    
766 nigel 47 Version 3.2 12-May-00
767     ---------------------
768    
769     This is purely a bug fixing release.
770    
771     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
772     of ZA. This was just one example of several cases that could provoke this bug,
773     which was introduced by change 9 of version 2.00. The code for breaking
774     infinite loops after an iteration that matches an empty string was't working
775     correctly.
776    
777     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
778     when matched against abbab (for example). After matching an empty string, it
779     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
780     caused it to match further down the string than it should.
781    
782     3. The code contained an inclusion of sys/types.h. It isn't clear why this
783     was there because it doesn't seem to be needed, and it causes trouble on some
784     systems, as it is not a Standard C header. It has been removed.
785    
786     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
787     were reported on the Macintosh. The changes were from
788    
789     while ((c = *(++ptr)) != 0 && c != '\n');
790     to
791     while ((c = *(++ptr)) != 0 && c != '\n') ;
792    
793     Totally extraordinary, but if that's what it takes...
794    
795     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
796     available. Added HAVE_BCOPY and an autoconf test for it; if neither
797     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
798     assumes the way PCRE uses memmove() (always moving upwards).
799    
800     6. PCRE is being used in one environment where strchr() is not available. There
801     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
802     faster code anyway.
803    
804    
805 nigel 45 Version 3.1 09-Feb-00
806     ---------------------
807    
808     The only change in this release is the fixing of some bugs in Makefile.in for
809     the "install" target:
810    
811     (1) It was failing to install pcreposix.h.
812    
813     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
814    
815    
816 nigel 43 Version 3.0 01-Feb-00
817     ---------------------
818 nigel 41
819     1. Add support for the /+ modifier to perltest (to output $` like it does in
820     pcretest).
821    
822     2. Add support for the /g modifier to perltest.
823    
824     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
825     matches null strings.
826    
827     4. Fix perltest so that it doesn't do unwanted things when fed an empty
828     pattern. Perl treats empty patterns specially - it reuses the most recent
829     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
830     effect.
831    
832     5. The POSIX interface was broken in that it was just handing over the POSIX
833     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
834     required a bigger vector, with some working space on the end. This means that
835     the POSIX wrapper now has to get and free some memory, and copy the results.
836    
837 nigel 43 6. Added some simple autoconf support, placing the test data and the
838     documentation in separate directories, re-organizing some of the
839     information files, and making it build pcre-config (a GNU standard). Also added
840     libtool support for building PCRE as a shared library, which is now the
841     default.
842 nigel 41
843 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
844     09 are not valid octal constants. Single digits will be used for minor values
845     less than 10.
846    
847     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
848     existing programs that set these in the POSIX interface can use PCRE without
849     modification.
850    
851     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
852     return all that pcre_info() returns, plus additional data. The pcre_info()
853     function is retained for compatibility, but is considered to be obsolete.
854    
855     10. Added experimental recursion feature (?R) to handle one common case that
856     Perl 5.6 will be able to do with (?p{...}).
857    
858     11. Added support for POSIX character classes like [:alpha:], which Perl is
859     adopting.
860    
861    
862 nigel 39 Version 2.08 31-Aug-99
863     ----------------------
864    
865     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
866     trying to match at the startoffset position, but instead was moving forward to
867     the next newline as if a previous match had failed.
868    
869     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
870     and could get into a loop if a null string was matched other than at the start
871     of the subject.
872    
873     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
874     be distinguished at compile time, and for completeness also added PCRE_DATE.
875    
876     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
877     in GnuWin32 environments.
878    
879    
880 nigel 37 Version 2.07 29-Jul-99
881     ----------------------
882    
883     1. The documentation is now supplied in plain text form and HTML as well as in
884     the form of man page sources.
885    
886     2. C++ compilers don't like assigning (void *) values to other pointer types.
887     In particular this affects malloc(). Although there is no problem in Standard
888     C, I've put in casts to keep C++ compilers happy.
889    
890     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
891     should be (const char *).
892    
893     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
894     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
895     However, I haven't made this a standard facility. The documentation doesn't
896     mention it, and the Makefile doesn't support it.
897    
898     5. The Makefile now contains an "install" target, with editable destinations at
899     the top of the file. The pcretest program is not installed.
900    
901     6. pgrep -V now gives the PCRE version number and date.
902    
903     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
904     causing the entire string to be ignored, instead of just the last character.
905    
906     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
907     non-matching string, it can take a very, very long time, even for strings of
908     quite modest length, because of the nested recursion. PCRE now does better in
909     some of these cases. It does this by remembering the last required literal
910     character in the pattern, and pre-searching the subject to ensure it is present
911     before running the real match. In other words, it applies a heuristic to detect
912     some types of certain failure quickly, and in the above example, if presented
913     with a string that has no trailing " it gives "no match" very quickly.
914    
915     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
916     other alternatives are tried instead.
917    
918    
919 nigel 35 Version 2.06 09-Jun-99
920     ----------------------
921    
922     1. Change pcretest's output for amount of store used to show just the code
923     space, because the remainder (the data block) varies in size between 32-bit and
924     64-bit systems.
925    
926     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
927     start matching at. This allows lookbehinds to work when searching for multiple
928     occurrences in a string.
929    
930     3. Added additional options to pcretest for testing multiple occurrences:
931    
932     /+ outputs the rest of the string that follows a match
933     /g loops for multiple occurrences, using the new startoffset argument
934     /G loops for multiple occurrences by passing an incremented pointer
935    
936     4. PCRE wasn't doing the "first character" optimization for patterns starting
937     with \b or \B, though it was doing it for other lookbehind assertions. That is,
938     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
939     the letter 'x'. On long subject strings, this gives a significant speed-up.
940    
941    
942 nigel 33 Version 2.05 21-Apr-99
943     ----------------------
944    
945     1. Changed the type of magic_number from int to long int so that it works
946     properly on 16-bit systems.
947    
948     2. Fixed a bug which caused patterns starting with .* not to work correctly
949     when the subject string contained newline characters. PCRE was assuming
950     anchoring for such patterns in all cases, which is not correct because .* will
951     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
952     DOTALL is set at top level; otherwise it knows that patterns starting with .*
953     must be retried after every newline in the subject.
954    
955    
956 nigel 31 Version 2.04 18-Feb-99
957     ----------------------
958    
959     1. For parenthesized subpatterns with repeats whose minimum was zero, the
960     computation of the store needed to hold the pattern was incorrect (too large).
961     If such patterns were nested a few deep, this could multiply and become a real
962     problem.
963    
964     2. Added /M option to pcretest to show the memory requirement of a specific
965     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
966    
967     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
968     compiled in such a way that the backtracking after subsequent failure was
969     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
970     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
971    
972    
973 nigel 29 Version 2.03 02-Feb-99
974     ----------------------
975    
976     1. Fixed typo and small mistake in man page.
977    
978 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
979     LICENCE file containing the conditions.
980 nigel 29
981     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
982     Perl, that is the internal \ allows the delimiter to be included in the
983     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
984     the final delimiter, add \ to the end of the pattern (to test the error).
985    
986     4. Added the convenience functions for extracting substrings after a successful
987     match. Updated pcretest to make it able to test these functions.
988    
989    
990 nigel 27 Version 2.02 14-Jan-99
991     ----------------------
992    
993     1. Initialized the working variables associated with each extraction so that
994     their saving and restoring doesn't refer to uninitialized store.
995    
996     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
997     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
998     fix the problem.
999    
1000     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
1001     calls, and wasn't printing the correct value for compiling calls. Increased the
1002     default value of LOOPREPEAT, and the number of significant figures in the
1003     times.
1004    
1005     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
1006    
1007     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
1008     a building problem on Windows NT with a FAT file system.
1009    
1010    
1011 nigel 25 Version 2.01 21-Oct-98
1012     ----------------------
1013    
1014     1. Changed the API for pcre_compile() to allow for the provision of a pointer
1015     to character tables built by pcre_maketables() in the current locale. If NULL
1016     is passed, the default tables are used.
1017    
1018    
1019 nigel 23 Version 2.00 24-Sep-98
1020 nigel 21 ----------------------
1021    
1022 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
1023     it any more.
1024    
1025     2. Allow quantification of (?>) groups, and make it work correctly.
1026    
1027     3. The first character computation wasn't working for (?>) groups.
1028    
1029     4. Correct the implementation of \Z (it is permitted to match on the \n at the
1030     end of the subject) and add 5.005's \z, which really does match only at the
1031     very end of the subject.
1032    
1033     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
1034    
1035     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
1036     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
1037     localized options. All options to pcre_study() were also removed.
1038    
1039     7. Add other new features from 5.005:
1040    
1041     $(?<= positive lookbehind
1042     $(?<! negative lookbehind
1043     (?imsx-imsx) added the unsetting capability
1044     such a setting is global if at outer level; local otherwise
1045     (?imsx-imsx:) non-capturing groups with option setting
1046     (?(cond)re|re) conditional pattern matching
1047    
1048     A backreference to itself in a repeated group matches the previous
1049     captured string.
1050    
1051     8. General tidying up of studying (both automatic and via "study")
1052     consequential on the addition of new assertions.
1053    
1054     9. As in 5.005, unlimited repeated groups that could match an empty substring
1055     are no longer faulted at compile time. Instead, the loop is forcibly broken at
1056     runtime if any iteration does actually match an empty substring.
1057    
1058     10. Include the RunTest script in the distribution.
1059    
1060     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
1061     discrepancies, some of which were old and were also with respect to 5.004. They
1062     have now been fixed.
1063    
1064    
1065     Version 1.09 28-Apr-98
1066     ----------------------
1067    
1068 nigel 21 1. A negated single character class followed by a quantifier with a minimum
1069     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
1070     program crashes, or just wrong answers. This did not apply to negated classes
1071     containing more than one character, or to minima other than one.
1072    
1073    
1074 nigel 19 Version 1.08 27-Mar-98
1075     ----------------------
1076    
1077     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
1078    
1079     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
1080     latter must appear before anything that relies on it in the pattern.
1081    
1082    
1083 nigel 17 Version 1.07 16-Feb-98
1084     ----------------------
1085    
1086     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
1087     repeat of a potentially empty string).
1088    
1089    
1090 nigel 15 Version 1.06 23-Jan-98
1091     ----------------------
1092    
1093     1. Added Markus Oberhumer's little patches for C++.
1094    
1095     2. Literal strings longer than 255 characters were broken.
1096    
1097    
1098 nigel 13 Version 1.05 23-Dec-97
1099     ----------------------
1100    
1101     1. Negated character classes containing more than one character were failing if
1102     PCRE_CASELESS was set at run time.
1103    
1104    
1105 nigel 11 Version 1.04 19-Dec-97
1106     ----------------------
1107    
1108     1. Corrected the man page, where some "const" qualifiers had been omitted.
1109    
1110     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
1111     input syntax.
1112    
1113     3. Fixed memory leak which occurred when a regex with back references was
1114     matched with an offsets vector that wasn't big enough. The temporary memory
1115     that is used in this case wasn't being freed if the match failed.
1116    
1117     4. Tidied pcretest to ensure it frees memory that it gets.
1118    
1119     5. Temporary memory was being obtained in the case where the passed offsets
1120     vector was exactly big enough.
1121    
1122     6. Corrected definition of offsetof() from change 5 below.
1123    
1124     7. I had screwed up change 6 below and broken the rules for the use of
1125     setjmp(). Now fixed.
1126    
1127    
1128 nigel 9 Version 1.03 18-Dec-97
1129     ----------------------
1130    
1131     1. A erroneous regex with a missing opening parenthesis was correctly
1132     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
1133     on some systems.
1134    
1135     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
1136     it was reported that one broken compiler failed on the former because "code" is
1137     also an independent variable.
1138    
1139     3. The erroneous regex a[]b caused an array overrun reference.
1140    
1141     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
1142     fail on data ending with that character. (It was going on too far, and checking
1143     the next character, typically a binary zero.) This was specific to the
1144     optimized code for single-character negative classes.
1145    
1146     5. Added a contributed patch from the TIN world which does the following:
1147    
1148     + Add an undef for memmove, in case the the system defines a macro for it.
1149    
1150     + Add a definition of offsetof(), in case there isn't one. (I don't know
1151     the reason behind this - offsetof() is part of the ANSI standard - but
1152     it does no harm).
1153    
1154     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
1155     most of the places where whitespace preceded '#'. I have given up and
1156     allowed the remaining 2 cases to be at the margin.
1157    
1158     + Rename some variables in pcre to eliminate shadowing. This seems very
1159     pedantic, but does no harm, of course.
1160    
1161     6. Moved the call to setjmp() into its own function, to get rid of warnings
1162     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
1163    
1164     7. Constructs such as \d{8,} were compiling into the equivalent of
1165 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
1166 nigel 9 outcome, but in this particular case used more store than had been allocated,
1167     which caused the bug to be discovered because it threw up an internal error.
1168    
1169     8. The debugging code in both pcre and pcretest for outputting the compiled
1170     form of a regex was going wrong in the case of back references followed by
1171     curly-bracketed repeats.
1172    
1173    
1174 nigel 7 Version 1.02 12-Dec-97
1175     ----------------------
1176    
1177     1. Typos in pcre.3 and comments in the source fixed.
1178    
1179     2. Applied a contributed patch to get rid of places where it used to remove
1180     'const' from variables, and fixed some signed/unsigned and uninitialized
1181     variable warnings.
1182    
1183     3. Added the "runtest" target to Makefile.
1184    
1185     4. Set default compiler flag to -O2 rather than just -O.
1186    
1187    
1188 nigel 5 Version 1.01 19-Nov-97
1189     ----------------------
1190    
1191     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
1192     like /([ab]*)*/, that is, for classes with more than one character in them.
1193    
1194     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
1195     as /((?>a*))*/ (a PCRE_EXTRA facility).
1196    
1197    
1198     Version 1.00 18-Nov-97
1199     ----------------------
1200    
1201     1. Added compile-time macros to support systems such as SunOS4 which don't have
1202     memmove() or strerror() but have other things that can be used instead.
1203    
1204     2. Arranged that "make clean" removes the executables.
1205    
1206    
1207 nigel 3 Version 0.99 27-Oct-97
1208     ----------------------
1209    
1210     1. Fixed bug in code for optimizing classes with only one character. It was
1211     initializing a 32-byte map regardless, which could cause it to run off the end
1212     of the memory it had got.
1213    
1214     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
1215    
1216    
1217     Version 0.98 22-Oct-97
1218     ----------------------
1219    
1220     1. Fixed bug in code for handling temporary memory usage when there are more
1221     back references than supplied space in the ovector. This could cause segfaults.
1222    
1223    
1224     Version 0.97 21-Oct-97
1225     ----------------------
1226    
1227     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
1228    
1229     2. Optimized negated single characters not to use a bit map.
1230    
1231     3. Brought error texts together as macro definitions; clarified some of them;
1232     fixed one that was wrong - it said "range out of order" when it meant "invalid
1233     escape sequence".
1234    
1235     4. Changed some char * arguments to const char *.
1236    
1237     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
1238    
1239     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
1240     pcretest.
1241    
1242    
1243     Version 0.96 16-Oct-97
1244     ----------------------
1245    
1246     1. Added a simple "pgrep" utility to the distribution.
1247    
1248     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
1249     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
1250     where "ddd" means "one or more decimal digits".
1251    
1252     3. Fixed serious bug. If a pattern had a back reference, but the call to
1253     pcre_exec() didn't supply a large enough ovector to record the related
1254     identifying subpattern, the match always failed. PCRE now remembers the number
1255     of the largest back reference, and gets some temporary memory in which to save
1256     the offsets during matching if necessary, in order to ensure that
1257     backreferences always work.
1258    
1259     4. Increased the compatibility with Perl in a number of ways:
1260    
1261     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
1262     to request this handling. The option can be set at compile or exec time.
1263    
1264     (b) $ matches before a terminating newline by default; an option
1265     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
1266     mode). The option can be set at compile or exec time.
1267    
1268     (c) The handling of \ followed by a digit other than 0 is now supposed to be
1269     the same as Perl's. If the decimal number it represents is less than 10
1270     or there aren't that many previous left capturing parentheses, an octal
1271     escape is read. Inside a character class, it's always an octal escape,
1272     even if it is a single digit.
1273    
1274     (d) An escaped but undefined alphabetic character is taken as a literal,
1275     unless PCRE_EXTRA is set. Currently this just reserves the remaining
1276     escapes.
1277    
1278     (e) {0} is now permitted. (The previous item is removed from the compiled
1279     pattern).
1280    
1281     5. Changed all the names of code files so that the basic parts are no longer
1282     than 10 characters, and abolished the teeny "globals.c" file.
1283    
1284     6. Changed the handling of character classes; they are now done with a 32-byte
1285     bit map always.
1286    
1287     7. Added the -d and /D options to pcretest to make it possible to look at the
1288     internals of compilation without having to recompile pcre.
1289    
1290    
1291     Version 0.95 23-Sep-97
1292     ----------------------
1293    
1294     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
1295     \x20 at the start of a run of normal characters. These were being treated as
1296     real characters, instead of the source characters being re-checked.
1297    
1298    
1299     Version 0.94 18-Sep-97
1300     ----------------------
1301    
1302     1. The functions are now thread-safe, with the caveat that the global variables
1303     containing pointers to malloc() and free() or alternative functions are the
1304     same for all threads.
1305    
1306     2. Get pcre_study() to generate a bitmap of initial characters for non-
1307     anchored patterns when this is possible, and use it if passed to pcre_exec().
1308    
1309    
1310     Version 0.93 15-Sep-97
1311     ----------------------
1312    
1313     1. /(b)|(:+)/ was computing an incorrect first character.
1314    
1315     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
1316     but not actually doing anything yet.
1317    
1318     3. Treat "-" characters in classes that cannot be part of ranges as literals,
1319     as Perl does (e.g. [-az] or [az-]).
1320    
1321     4. Set the anchored flag if a branch starts with .* or .*? because that tests
1322     all possible positions.
1323    
1324     5. Split up into different modules to avoid including unneeded functions in a
1325     compiled binary. However, compile and exec are still in one module. The "study"
1326     function is split off.
1327    
1328     6. The character tables are now in a separate module whose source is generated
1329     by an auxiliary program - but can then be edited by hand if required. There are
1330     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
1331     toupper() in the code.
1332    
1333     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
1334     make them global. Abolish the function for setting them, as the caller can now
1335     set them directly.
1336    
1337    
1338     Version 0.92 11-Sep-97
1339     ----------------------
1340    
1341     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
1342     (e.g. /a{1,3}/) was broken (I mis-optimized it).
1343    
1344     2. Caseless matching was not working in character classes if the characters in
1345     the pattern were in upper case.
1346    
1347     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
1348    
1349     4. Make PCRE_ANCHORED public and accept as a compile option.
1350    
1351     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
1352     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
1353     pass them.
1354    
1355     6. Give an error if bad option bits passed at compile or run time.
1356    
1357     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
1358     pcretest to cause it to pass that flag.
1359    
1360     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
1361     options, and the first character, if set.
1362    
1363     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
1364    
1365    
1366     Version 0.91 10-Sep-97
1367     ----------------------
1368    
1369     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
1370     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
1371    
1372     2. PCRE was looping on encountering an indefinitely repeated back reference to
1373     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
1374     Perl does - treats the match as successful.
1375    
1376     ****

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