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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 7.5 29-Dec-07
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
54    
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
68    
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
73    
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
78    
79    14. Added --file-offsets and --line-offsets to pcregrep.
80    
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
85    
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
89    
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
95    
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
97    
98    19. Added --enable-pcretest-libreadline.
99    
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I have removed one of the increments.
103    
104    21. Several CMake things:
105    
106        (1) Arranged that, when cmake is used on Unix, the libraries end up with
107            the names libpcre and libpcreposix, not just pcre and pcreposix.
108    
109        (2) The above change means that pcretest and pcregrep are now correctly
110            linked with the newly-built libraries, not previously installed ones.
111    
112        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
113    
114    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
115        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
116        UTF-8 newline character). The key issue is that the pattern starts .*;
117        this means that the match must be either at the beginning, or after a
118        newline. The bug was in the code for advancing after a failed match and
119        checking that the new position followed a newline. It was not taking
120        account of UTF-8 characters correctly.
121    
122    
123    Version 7.4 21-Sep-07
124    ---------------------
125    
126    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
127        means that a class such as [\s] counted as "explicit reference to CR or
128        LF". That isn't really right - the whole point of the change was to try to
129        help when there was an actual mention of one of the two characters. So now
130        the change happens only if \r or \n (or a literal CR or LF) character is
131        encountered.
132    
133    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
134        of both had grown to the point where there were only 3 bits left.
135        Fortunately, there was spare space in the data structure, and so I have
136        moved the internal flags into a new 16-bit field to free up more option
137        bits.
138    
139    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
140        but did not set the internal JCHANGED flag - either of these is enough to
141        control the way the "get" function works - but the PCRE_INFO_JCHANGED
142        facility is supposed to tell if (?J) was ever used, so now (?J) at the
143        start sets both bits.
144    
145    4.  Added options (at build time, compile time, exec time) to change \R from
146        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
147    
148    5.  doc/pcresyntax.html was missing from the distribution.
149    
150    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
151        compatibility, even though it is no longer used.
152    
153    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
154        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
155        windows.h file is present (where different names are used). [This was
156        reversed later after testing - see 16 below.]
157    
158    8.  Changed all #include <config.h> to #include "config.h". There were also
159        some further <pcre.h> cases that I changed to "pcre.h".
160    
161    9.  When pcregrep was used with the --colour option, it missed the line ending
162        sequence off the lines that it output.
163    
164    10. It was pointed out to me that arrays of string pointers cause lots of
165        relocations when a shared library is dynamically loaded. A technique of
166        using a single long string with a table of offsets can drastically reduce
167        these. I have refactored PCRE in four places to do this. The result is
168        dramatic:
169    
170          Originally:                          290
171          After changing UCP table:            187
172          After changing error message table:   43
173          After changing table of "verbs"       36
174          After changing table of Posix names   22
175    
176        Thanks to the folks working on Gregex for glib for this insight.
177    
178    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
179        unicode-properties was also set.
180    
181    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
182    
183    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
184        checked only for CRLF.
185    
186    14. Added casts to pcretest.c to avoid compiler warnings.
187    
188    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
189    
190    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
191        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
192        entirely. This removes changes made in 7 above.
193    
194    17. The CMake files have been updated, and there is now more information about
195        building with CMake in the NON-UNIX-USE document.
196    
197    
198    Version 7.3 28-Aug-07
199    ---------------------
200    
201     1. In the rejigging of the build system that eventually resulted in 7.1, the
202        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
203        brackets there is not right, since it causes compilers to look for an
204        installed pcre.h, not the version that is in the source that is being
205        compiled (which of course may be different). I have changed it back to:
206    
207          #include "pcre.h"
208    
209        I have a vague recollection that the change was concerned with compiling in
210        different directories, but in the new build system, that is taken care of
211        by the VPATH setting the Makefile.
212    
213     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
214        when the subject happened to end in the byte 0x85 (e.g. if the last
215        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
216        characters but of course it shouldn't be taken as a newline when it is part
217        of another character. The bug was that, for an unlimited repeat of . in
218        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
219        characters when looking for a newline.
220    
221     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
222    
223     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
224        in debug output.
225    
226     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
227        long printing in the pcrecpp unittest when running under MinGW.
228    
229     6. ESC_K was left out of the EBCDIC table.
230    
231     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
232        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
233        limit also applies to "virtual nesting" when a pattern is recursive, and in
234        this case 1000 isn't so big. I have been able to remove this limit at the
235        expense of backing off one optimization in certain circumstances. Normally,
236        when pcre_exec() would call its internal match() function recursively and
237        immediately return the result unconditionally, it uses a "tail recursion"
238        feature to save stack. However, when a subpattern that can match an empty
239        string has an unlimited repetition quantifier, it no longer makes this
240        optimization. That gives it a stack frame in which to save the data for
241        checking that an empty string has been matched. Previously this was taken
242        from the 1000-entry workspace that had been reserved. So now there is no
243        explicit limit, but more stack is used.
244    
245     8. Applied Daniel's patches to solve problems with the import/export magic
246        syntax that is required for Windows, and which was going wrong for the
247        pcreposix and pcrecpp parts of the library. These were overlooked when this
248        problem was solved for the main library.
249    
250     9. There were some crude static tests to avoid integer overflow when computing
251        the size of patterns that contain repeated groups with explicit upper
252        limits. As the maximum quantifier is 65535, the maximum group length was
253        set at 30,000 so that the product of these two numbers did not overflow a
254        32-bit integer. However, it turns out that people want to use groups that
255        are longer than 30,000 bytes (though not repeat them that many times).
256        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
257        made it possible to implement the integer overflow checks in a much more
258        dynamic way, which I have now done. The artificial limitation on group
259        length has been removed - we now have only the limit on the total length of
260        the compiled pattern, which depends on the LINK_SIZE setting.
261    
262    10. Fixed a bug in the documentation for get/copy named substring when
263        duplicate names are permitted. If none of the named substrings are set, the
264        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
265        empty string.
266    
267    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
268        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
269        because the ] is interpreted as the first data character and the
270        terminating ] is not found. PCRE has been made compatible with Perl in this
271        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
272        cause memory overwriting.
273    
274    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
275        string has been matched (to stop an infinite loop). It was not recognizing
276        a conditional subpattern that could match an empty string if that
277        subpattern was within another subpattern. For example, it looped when
278        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
279        condition was not nested. This bug has been fixed.
280    
281    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
282        past the start of the subject in the presence of bytes with the top bit
283        set, for example "\x8aBCD".
284    
285    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
286        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
287    
288    14. Optimized (?!) to (*FAIL).
289    
290    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
291        This restricts code points to be within the range 0 to 0x10FFFF, excluding
292        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
293        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
294        does: it's just the validity check that is more restrictive.
295    
296    16. Inserted checks for integer overflows during escape sequence (backslash)
297        processing, and also fixed erroneous offset values for syntax errors during
298        backslash processing.
299    
300    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
301        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
302    
303    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
304        caused an overrun.
305    
306    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
307        something other than just ASCII characters) inside a group that had an
308        unlimited repeat caused a loop at compile time (while checking to see
309        whether the group could match an empty string).
310    
311    20. Debugging a pattern containing \p or \P could cause a crash. For example,
312        [\P{Any}] did so. (Error in the code for printing property names.)
313    
314    21. An orphan \E inside a character class could cause a crash.
315    
316    22. A repeated capturing bracket such as (A)? could cause a wild memory
317        reference during compilation.
318    
319    23. There are several functions in pcre_compile() that scan along a compiled
320        expression for various reasons (e.g. to see if it's fixed length for look
321        behind). There were bugs in these functions when a repeated \p or \P was
322        present in the pattern. These operators have additional parameters compared
323        with \d, etc, and these were not being taken into account when moving along
324        the compiled data. Specifically:
325    
326        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
327            length.
328    
329        (b) An item such as \pL+ within a repeated group could cause crashes or
330            loops.
331    
332        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
333            "reference to non-existent subpattern" error.
334    
335        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
336    
337    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
338        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
339    
340    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
341    
342    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
343        character were causing crashes (broken optimization).
344    
345    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
346        \p or \P) caused a compile-time loop.
347    
348    28. More problems have arisen in unanchored patterns when CRLF is a valid line
349        break. For example, the unstudied pattern [\r\n]A does not match the string
350        "\r\nA" because change 7.0/46 below moves the current point on by two
351        characters after failing to match at the start. However, the pattern \nA
352        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
353        the same is true. There doesn't seem any very clean way out of this, but
354        what I have chosen to do makes the common cases work: PCRE now takes note
355        of whether there can be an explicit match for \r or \n anywhere in the
356        pattern, and if so, 7.0/46 no longer applies. As part of this change,
357        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
358        pattern has explicit CR or LF references.
359    
360    29. Added (*CR) etc for changing newline setting at start of pattern.
361    
362    
363    Version 7.2 19-Jun-07
364    ---------------------
365    
366     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
367        which is apparently normally available under Windows.
368    
369     2. Re-jig the pcregrep tests with different newline settings in an attempt
370        to make them independent of the local environment's newline setting.
371    
372     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
373    
374     4. Some of the "internals" tests were previously cut out when the link size
375        was not 2, because the output contained actual offsets. The recent new
376        "Z" feature of pcretest means that these can be cut out, making the tests
377        usable with all link sizes.
378    
379     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
380        stack recursion. This gives a massive performance boost under BSD, but just
381        a small improvement under Linux. However, it saves one field in the frame
382        in all cases.
383    
384     6. Added more features from the forthcoming Perl 5.10:
385    
386        (a) (?-n) (where n is a string of digits) is a relative subroutine or
387            recursion call. It refers to the nth most recently opened parentheses.
388    
389        (b) (?+n) is also a relative subroutine call; it refers to the nth next
390            to be opened parentheses.
391    
392        (c) Conditions that refer to capturing parentheses can be specified
393            relatively, for example, (?(-2)... or (?(+3)...
394    
395        (d) \K resets the start of the current match so that everything before
396            is not part of it.
397    
398        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
399    
400        (f) \g{name} is another synonym - part of Perl 5.10's unification of
401            reference syntax.
402    
403        (g) (?| introduces a group in which the numbering of parentheses in each
404            alternative starts with the same number.
405    
406        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
407    
408     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
409        PCRE_INFO_JCHANGED.
410    
411     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
412        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
413        for detecting groups that can match an empty string.
414    
415     9. A pattern with a very large number of alternatives (more than several
416        hundred) was running out of internal workspace during the pre-compile
417        phase, where pcre_compile() figures out how much memory will be needed. A
418        bit of new cunning has reduced the workspace needed for groups with
419        alternatives. The 1000-alternative test pattern now uses 12 bytes of
420        workspace instead of running out of the 4096 that are available.
421    
422    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
423    
424    11. Applied patch from Google to remove an optimization that didn't quite work.
425        The report of the bug said:
426    
427          pcrecpp::RE("a*").FullMatch("aaa") matches, while
428          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
429          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
430    
431    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
432        it matched the wrong number of bytes.
433    
434    
435    Version 7.1 24-Apr-07
436  ---------------------  ---------------------
437    
438   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 143  Version 7.1 12-Mar-07 Line 574  Version 7.1 12-Mar-07
574  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
575      CRLF as a newline sequence.      CRLF as a newline sequence.
576    
577    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
578        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
579        I have nevertheless tidied it up.
580    
581    23. Added some casts to kill warnings from HP-UX ia64 compiler.
582    
583    24. Added a man page for pcre-config.
584    
585    
586  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
587  ---------------------  ---------------------

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