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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.1 05-Mar-07  Version 7.4 10-Sep-07
5  ---------------------  ---------------------
7   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one  1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8      that is more "standard", making use of automake and other autotools. There      means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
26    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
29    5.  doc/pcresyntax.html was missing from the distribution.
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 (where
36        different names are used).
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
56        Thanks to the folks working on Gregex for glib for this insight.
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
62    Version 7.3 28-Aug-07
63    ---------------------
65     1. In the rejigging of the build system that eventually resulted in 7.1, the
66        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
67        brackets there is not right, since it causes compilers to look for an
68        installed pcre.h, not the version that is in the source that is being
69        compiled (which of course may be different). I have changed it back to:
71          #include "pcre.h"
73        I have a vague recollection that the change was concerned with compiling in
74        different directories, but in the new build system, that is taken care of
75        by the VPATH setting the Makefile.
77     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
78        when the subject happened to end in the byte 0x85 (e.g. if the last
79        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
80        characters but of course it shouldn't be taken as a newline when it is part
81        of another character. The bug was that, for an unlimited repeat of . in
82        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
83        characters when looking for a newline.
85     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
87     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
88        in debug output.
90     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
91        long printing in the pcrecpp unittest when running under MinGW.
93     6. ESC_K was left out of the EBCDIC table.
95     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
96        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
97        limit also applies to "virtual nesting" when a pattern is recursive, and in
98        this case 1000 isn't so big. I have been able to remove this limit at the
99        expense of backing off one optimization in certain circumstances. Normally,
100        when pcre_exec() would call its internal match() function recursively and
101        immediately return the result unconditionally, it uses a "tail recursion"
102        feature to save stack. However, when a subpattern that can match an empty
103        string has an unlimited repetition quantifier, it no longer makes this
104        optimization. That gives it a stack frame in which to save the data for
105        checking that an empty string has been matched. Previously this was taken
106        from the 1000-entry workspace that had been reserved. So now there is no
107        explicit limit, but more stack is used.
109     8. Applied Daniel's patches to solve problems with the import/export magic
110        syntax that is required for Windows, and which was going wrong for the
111        pcreposix and pcrecpp parts of the library. These were overlooked when this
112        problem was solved for the main library.
114     9. There were some crude static tests to avoid integer overflow when computing
115        the size of patterns that contain repeated groups with explicit upper
116        limits. As the maximum quantifier is 65535, the maximum group length was
117        set at 30,000 so that the product of these two numbers did not overflow a
118        32-bit integer. However, it turns out that people want to use groups that
119        are longer than 30,000 bytes (though not repeat them that many times).
120        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
121        made it possible to implement the integer overflow checks in a much more
122        dynamic way, which I have now done. The artificial limitation on group
123        length has been removed - we now have only the limit on the total length of
124        the compiled pattern, which depends on the LINK_SIZE setting.
126    10. Fixed a bug in the documentation for get/copy named substring when
127        duplicate names are permitted. If none of the named substrings are set, the
128        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
129        empty string.
131    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
132        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
133        because the ] is interpreted as the first data character and the
134        terminating ] is not found. PCRE has been made compatible with Perl in this
135        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
136        cause memory overwriting.
138    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
139        string has been matched (to stop an infinite loop). It was not recognizing
140        a conditional subpattern that could match an empty string if that
141        subpattern was within another subpattern. For example, it looped when
142        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
143        condition was not nested. This bug has been fixed.
145    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
146        past the start of the subject in the presence of bytes with the top bit
147        set, for example "\x8aBCD".
149    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
150        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
152    14. Optimized (?!) to (*FAIL).
154    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
155        This restricts code points to be within the range 0 to 0x10FFFF, excluding
156        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
157        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
158        does: it's just the validity check that is more restrictive.
160    16. Inserted checks for integer overflows during escape sequence (backslash)
161        processing, and also fixed erroneous offset values for syntax errors during
162        backslash processing.
164    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
165        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
167    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
168        caused an overrun.
170    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
171        something other than just ASCII characters) inside a group that had an
172        unlimited repeat caused a loop at compile time (while checking to see
173        whether the group could match an empty string).
175    20. Debugging a pattern containing \p or \P could cause a crash. For example,
176        [\P{Any}] did so. (Error in the code for printing property names.)
178    21. An orphan \E inside a character class could cause a crash.
180    22. A repeated capturing bracket such as (A)? could cause a wild memory
181        reference during compilation.
183    23. There are several functions in pcre_compile() that scan along a compiled
184        expression for various reasons (e.g. to see if it's fixed length for look
185        behind). There were bugs in these functions when a repeated \p or \P was
186        present in the pattern. These operators have additional parameters compared
187        with \d, etc, and these were not being taken into account when moving along
188        the compiled data. Specifically:
190        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
191            length.
193        (b) An item such as \pL+ within a repeated group could cause crashes or
194            loops.
196        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
197            "reference to non-existent subpattern" error.
199        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
201    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
202        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
204    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
206    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
207        character were causing crashes (broken optimization).
209    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
210        \p or \P) caused a compile-time loop.
212    28. More problems have arisen in unanchored patterns when CRLF is a valid line
213        break. For example, the unstudied pattern [\r\n]A does not match the string
214        "\r\nA" because change 7.0/46 below moves the current point on by two
215        characters after failing to match at the start. However, the pattern \nA
216        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
217        the same is true. There doesn't seem any very clean way out of this, but
218        what I have chosen to do makes the common cases work: PCRE now takes note
219        of whether there can be an explicit match for \r or \n anywhere in the
220        pattern, and if so, 7.0/46 no longer applies. As part of this change,
221        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
222        pattern has explicit CR or LF references.
224    29. Added (*CR) etc for changing newline setting at start of pattern.
227    Version 7.2 19-Jun-07
228    ---------------------
230     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
231        which is apparently normally available under Windows.
233     2. Re-jig the pcregrep tests with different newline settings in an attempt
234        to make them independent of the local environment's newline setting.
236     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
238     4. Some of the "internals" tests were previously cut out when the link size
239        was not 2, because the output contained actual offsets. The recent new
240        "Z" feature of pcretest means that these can be cut out, making the tests
241        usable with all link sizes.
243     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
244        stack recursion. This gives a massive performance boost under BSD, but just
245        a small improvement under Linux. However, it saves one field in the frame
246        in all cases.
248     6. Added more features from the forthcoming Perl 5.10:
250        (a) (?-n) (where n is a string of digits) is a relative subroutine or
251            recursion call. It refers to the nth most recently opened parentheses.
253        (b) (?+n) is also a relative subroutine call; it refers to the nth next
254            to be opened parentheses.
256        (c) Conditions that refer to capturing parentheses can be specified
257            relatively, for example, (?(-2)... or (?(+3)...
259        (d) \K resets the start of the current match so that everything before
260            is not part of it.
262        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
264        (f) \g{name} is another synonym - part of Perl 5.10's unification of
265            reference syntax.
267        (g) (?| introduces a group in which the numbering of parentheses in each
268            alternative starts with the same number.
270        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
272     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
275     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
276        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
277        for detecting groups that can match an empty string.
279     9. A pattern with a very large number of alternatives (more than several
280        hundred) was running out of internal workspace during the pre-compile
281        phase, where pcre_compile() figures out how much memory will be needed. A
282        bit of new cunning has reduced the workspace needed for groups with
283        alternatives. The 1000-alternative test pattern now uses 12 bytes of
284        workspace instead of running out of the 4096 that are available.
286    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
288    11. Applied patch from Google to remove an optimization that didn't quite work.
289        The report of the bug said:
291          pcrecpp::RE("a*").FullMatch("aaa") matches, while
292          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
293          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
295    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
296        it matched the wrong number of bytes.
299    Version 7.1 24-Apr-07
300    ---------------------
302     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
303        that is more "standard", making use of automake and other Autotools. There
304      is some re-arrangement of the files and adjustment of comments consequent      is some re-arrangement of the files and adjustment of comments consequent
305      on this.      on this.
307   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
308      for recursive directory scanning broke on some systems because the files      for recursive directory scanning broke on some systems because the files
309      are not scanned in any specific order and on different systems the order      are not scanned in any specific order and on different systems the order
310      was different. A call to "sort" has been inserted into RunGrepTest for the      was different. A call to "sort" has been inserted into RunGrepTest for the
311      approprate test as a short-term fix. In the longer term there may be an      approprate test as a short-term fix. In the longer term there may be an
312      alternative.      alternative.
314   3. I had an email from Eric Raymond about problems translating some of PCRE's   3. I had an email from Eric Raymond about problems translating some of PCRE's
315      man pages to HTML (despite the fact that I distribute HTML pages, some      man pages to HTML (despite the fact that I distribute HTML pages, some
316      people do their own conversions for various reasons). The problems      people do their own conversions for various reasons). The problems
317      concerned the use of low-level troff macros .br and .in. I have therefore      concerned the use of low-level troff macros .br and .in. I have therefore
318      removed all such uses from the man pages (some were redundant, some could      removed all such uses from the man pages (some were redundant, some could
319      be replaced by .nf/.fi pairs). The maintain/132html script that I use to      be replaced by .nf/.fi pairs). The 132html script that I use to generate
320      generate HTML has been updated to handle .nf/.fi and to complain if it      HTML has been updated to handle .nf/.fi and to complain if it encounters
321      encounters .br or .in.      .br or .in.
323   4. Updated comments in configure.ac that get placed in config.h.in and also   4. Updated comments in configure.ac that get placed in config.h.in and also
324      arranged for config.h to be included in the distribution, for the benefit      arranged for config.h to be included in the distribution, with the name
325      of those who have to compile without Autotools (compare pcre.h).      config.h.generic, for the benefit of those who have to compile without
326        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
328     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
329        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
330        makevp.bat for the current PCRE, using the additional files
331        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
333     6. A Windows user reported a minor discrepancy with test 2, which turned out
334        to be caused by a trailing space on an input line that had got lost in his
335        copy. The trailing space was an accident, so I've just removed it.
337     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
338        that is needed.
340     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
341        as "const" (a) because they are and (b) because it helps the PHP
342        maintainers who have recently made a script to detect big data structures
343        in the php code that should be moved to the .rodata section. I remembered
344        to update Builducptable as well, so it won't revert if ucptable.h is ever
345        re-created.
347     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
348        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
349        order to be able to cut out the UTF-8 tables in the latter when UTF-8
350        support is not required. This saves 1.5-2K of code, which is important in
351        some applications.
353        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
354        so as not to refer to the tables, even though these functions will never be
355        called when UTF-8 support is disabled. Otherwise there are problems with a
356        shared library.
358    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
360        (a) It was defining its arguments as char * instead of void *.
362        (b) It was assuming that all moves were upwards in memory; this was true
363            a long time ago when I wrote it, but is no longer the case.
365        The emulated memove() is provided for those environments that have neither
366        memmove() nor bcopy(). I didn't think anyone used it these days, but that
367        is clearly not the case, as these two bugs were recently reported.
369    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
370        and Detrail to create the HTML documentation, the .txt form of the man
371        pages, and it removes trailing spaces from listed files. It also creates
372        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
373        case, it wraps all the #defines with #ifndefs. This script should be run
374        before "make dist".
376    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
377        with Unicode property support.
379        (a) For a maximizing quantifier, if the two different cases of the
380            character were of different lengths in their UTF-8 codings (there are
381            some cases like this - I found 11), and the matching function had to
382            back up over a mixture of the two cases, it incorrectly assumed they
383            were both the same length.
385        (b) When PCRE was configured to use the heap rather than the stack for
386            recursion during matching, it was not correctly preserving the data for
387            the other case of a UTF-8 character when checking ahead for a match
388            while processing a minimizing repeat. If the check also involved
389            matching a wide character, but failed, corruption could cause an
390            erroneous result when trying to check for a repeat of the original
391            character.
393    13. Some tidying changes to the testing mechanism:
395        (a) The RunTest script now detects the internal link size and whether there
396            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
397            values substituted by "configure". (The RunGrepTest script already did
398            this for UTF-8.) The configure.ac script no longer substitutes the
399            relevant variables.
401        (b) The debugging options /B and /D in pcretest show the compiled bytecode
402            with length and offset values. This means that the output is different
403            for different internal link sizes. Test 2 is skipped for link sizes
404            other than 2 because of this, bypassing the problem. Unfortunately,
405            there was also a test in test 3 (the locale tests) that used /B and
406            failed for link sizes other than 2. Rather than cut the whole test out,
407            I have added a new /Z option to pcretest that replaces the length and
408            offset values with spaces. This is now used to make test 3 independent
409            of link size. (Test 2 will be tidied up later.)
411    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
412        segmentation fault instead of returning the appropriate error message.
414    15. In multiline mode when the newline sequence was set to "any", the pattern
415        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
416        This doesn't seem right; it now treats the CRLF combination as the line
417        ending, and so does not match in that case. It's only a pattern such as ^$
418        that would hit this one: something like ^ABC$ would have failed after \r
419        and then tried again after \r\n.
421    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
422        in an attempt to make files that differ only in their line terminators
423        compare equal. This works on Linux.
425    17. Under certain error circumstances pcregrep might try to free random memory
426        as it exited. This is now fixed, thanks to valgrind.
428    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
429        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
430        was because its rules for how to advance for /g after matching an empty
431        string at the end of a line did not allow for this case. They now check for
432        it specially.
434    20. pcretest is supposed to handle patterns and data of any length, by
435        extending its buffers when necessary. It was getting this wrong when the
436        buffer for a data line had to be extended.
438    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
439        CRLF as a newline sequence.
441    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
442        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
443        I have nevertheless tidied it up.
445    23. Added some casts to kill warnings from HP-UX ia64 compiler.
447    24. Added a man page for pcre-config.
450  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
451  ---------------------  ---------------------

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