ChangeLog for PCRE

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Version 7.9 11-Apr-09

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1.  When building with support for bzlib/zlib (pcregrep) and/or readline

    (pcretest), all targets were linked against these libraries. This included

    libpcre, libpcreposix, and libpcrecpp, even though they do not use these

    libraries. This caused unwanted dependencies to be created. This problem

    has been fixed, and now only pcregrep is linked with bzlib/zlib and only

    pcretest is linked with readline.

2.  The "typedef int BOOL" in pcre_internal.h that was included inside the

    "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been

    moved outside it again, because FALSE and TRUE are already defined in AIX,

    but BOOL is not.

3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and

    PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.

4.  The pcregrep documentation said spaces were inserted as well as colons (or

    hyphens) following file names and line numbers when outputting matching

    lines. This is not true; no spaces are inserted. I have also clarified the

    wording for the --colour (or --color) option.

5.  In pcregrep, when --colour was used with -o, the list of matching strings

    was not coloured; this is different to GNU grep, so I have changed it to be

    the same.

6.  When --colo(u)r was used in pcregrep, only the first matching substring in

    each matching line was coloured. Now it goes on to look for further matches

    of any of the test patterns, which is the same behaviour as GNU grep.

7.  A pattern that could match an empty string could cause pcregrep to loop; it

    doesn't make sense to accept an empty string match in pcregrep, so I have

    locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this

    seems to be how GNU grep behaves.

8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at

    start or after a newline", because the conditional assertion was not being

    correctly handled. The rule now is that both the assertion and what follows

    in the first alternative must satisfy the test.

9.  If auto-callout was enabled in a pattern with a conditional group whose

    condition was an assertion, PCRE could crash during matching, both with

    pcre_exec() and pcre_dfa_exec().

10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was

    used for matching.

11. Unicode property support in character classes was not working for

    characters (bytes) greater than 127 when not in UTF-8 mode.

12. Added the -M command line option to pcretest.

14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.

15. Added the PCRE_NO_START_OPTIMIZE match-time option.

16. Added comments and documentation about mis-use of no_arg in the C++

    wrapper.

17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch

    from Martin Jerabek that uses macro names for all relevant character and

    string constants.

18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and

    SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without

    SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of

    these, but not everybody uses configure.

19. A conditional group that had only one branch was not being correctly

    recognized as an item that could match an empty string. This meant that an

    enclosing group might also not be so recognized, causing infinite looping

    (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$

    with the subject "ab", where knowledge that the repeated group can match

    nothing is needed in order to break the loop.

20. If a pattern that was compiled with callouts was matched using pcre_dfa_

    exec(), but without supplying a callout function, matching went wrong.

21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory

    leak if the size of the offset vector was greater than 30. When the vector

    is smaller, the saved offsets during recursion go onto a local stack

    vector, but for larger vectors malloc() is used. It was failing to free

    when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"

    error, in fact).

22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the

    heapframe that is used only when UTF-8 support is enabled. This caused no

    problem, but was untidy.

23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name

    CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is

    included within another project.

24. Steven Van Ingelgem's patches to add more options to the CMake support,

    slightly modified by me:

      (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including

          not building pcregrep.

      (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only

          if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.

25. Forward references, both numeric and by name, in patterns that made use of

    duplicate group numbers, could behave incorrectly or give incorrect errors,

    because when scanning forward to find the reference group, PCRE was not

    taking into account the duplicate group numbers. A pattern such as

    ^X(?3)(a)(?|(b)|(q))(Y) is an example.

26. Changed a few more instances of "const unsigned char *" to USPTR, making

    the feature of a custom pointer more persuasive (as requested by a user).

27. Wrapped the definitions of fileno and isatty for Windows, which appear in

    pcretest.c, inside #ifndefs, because it seems they are sometimes already

    pre-defined.

28. Added support for (*UTF8) at the start of a pattern.

29. Arrange for flags added by the "release type" setting in CMake to be shown

    in the configuration summary.

Version 7.8 05-Sep-08

---------------------

1.  Replaced UCP searching code with optimized version as implemented for Ad

    Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-

    stage table and inline lookup instead of a function, giving speed ups of 2

    to 5 times on some simple patterns that I tested. Permission was given to

    distribute the MultiStage2.py script that generates the tables (it's not in

    the tarball, but is in the Subversion repository).

2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more

    scripts.

3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained

    a group with a zero qualifier. The result of the study could be incorrect,

    or the function might crash, depending on the pattern.

4.  Caseless matching was not working for non-ASCII characters in back

    references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.

    It now works when Unicode Property Support is available.

5.  In pcretest, an escape such as \x{de} in the data was always generating

    a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in

    non-UTF-8 mode. If the value is greater than 255, it gives a warning about

    truncation.

6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).

7.  Added two (int) casts to pcregrep when printing the difference of two

    pointers, in case they are 64-bit values.

8.  Added comments about Mac OS X stack usage to the pcrestack man page and to

    test 2 if it fails.

9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,

    and a #define of that name to empty if it is not externally set. This is to

    allow users of MSVC to set it if necessary.

10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from

    the convenience functions in the pcre_get.c source file.

11. An option change at the start of a pattern that had top-level alternatives

    could cause overwriting and/or a crash. This command provoked a crash in

    some environments:

      printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest

    This potential security problem was recorded as CVE-2008-2371.

12. For a pattern where the match had to start at the beginning or immediately

    after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and

    pcre_dfa_exec() could read past the end of the passed subject if there was

    no match. To help with detecting such bugs (e.g. with valgrind), I modified

    pcretest so that it places the subject at the end of its malloc-ed buffer.

13. The change to pcretest in 12 above threw up a couple more cases when pcre_

    exec() might read past the end of the data buffer in UTF-8 mode.

14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and

    the data contained the byte 0x85 as part of a UTF-8 character within its

    first line. This applied both to normal and DFA matching.

15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,

    /^[^d]*?$/8 failed to match "abc".

16. Added a missing copyright notice to pcrecpp_internal.h.

17. Make it more clear in the documentation that values returned from

    pcre_exec() in ovector are byte offsets, not character counts.

18. Tidied a few places to stop certain compilers from issuing warnings.

19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as

    supplied by Stefan Weber. I made a further small update for 7.8 because

    there is a change of source arrangements: the pcre_searchfuncs.c module is

    replaced by pcre_ucd.c.

Version 7.7 07-May-08

---------------------

1.  Applied Craig's patch to sort out a long long problem: "If we can't convert

    a string to a long long, pretend we don't even have a long long." This is

    done by checking for the strtoq, strtoll, and _strtoi64 functions.

2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with

    pre-7.6 versions, which defined a global no_arg variable instead of putting

    it in the RE class. (See also #8 below.)

3.  Remove a line of dead code, identified by coverity and reported by Nuno

    Lopes.

4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:

    (1) The include/exclude patterns were being applied to the whole pathnames

        of files, instead of just to the final components.

    (2) If there was more than one level of directory, the subdirectories were

        skipped unless they satisfied the include/exclude conditions. This is

        inconsistent with GNU grep (and could even be seen as contrary to the

        pcregrep specification - which I improved to make it absolutely clear).

        The action now is always to scan all levels of directory, and just

        apply the include/exclude patterns to regular files.

5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used

    --exclude_dir in the tests to avoid scanning .svn directories.

6.  Applied Craig's patch to the QuoteMeta function so that it escapes the

    NUL character as backslash + 0 rather than backslash + NUL, because PCRE

    doesn't support NULs in patterns.

7.  Added some missing "const"s to declarations of static tables in

    pcre_compile.c and pcre_dfa_exec.c.

8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was

    caused by fix #2  above. (Subsequently also a second patch to fix the

    first patch. And a third patch - this was a messy problem.)

9.  Applied Craig's patch to remove the use of push_back().

10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX

    matching function regexec().

11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',

    which, however, unlike Perl's \g{...}, are subroutine calls, not back

    references. PCRE supports relative numbers with this syntax (I don't think

    Oniguruma does).

12. Previously, a group with a zero repeat such as (...){0} was completely

    omitted from the compiled regex. However, this means that if the group

    was called as a subroutine from elsewhere in the pattern, things went wrong

    (an internal error was given). Such groups are now left in the compiled

    pattern, with a new opcode that causes them to be skipped at execution

    time.

13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes

    to the way PCRE behaves:

    (a) A lone ] character is dis-allowed (Perl treats it as data).

    (b) A back reference to an unmatched subpattern matches an empty string

        (Perl fails the current match path).

    (c) A data ] in a character class must be notated as \] because if the

        first data character in a class is ], it defines an empty class. (In

        Perl it is not possible to have an empty class.) The empty class []

        never matches; it forces failure and is equivalent to (*FAIL) or (?!).

        The negative empty class [^] matches any one character, independently

        of the DOTALL setting.

14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a

    non-existent subpattern following a character class starting with ']' and

    containing () gave an internal compiling error instead of "reference to

    non-existent subpattern". Fortunately, when the pattern did exist, the

    compiled code was correct. (When scanning forwards to check for the

    existencd of the subpattern, it was treating the data ']' as terminating

    the class, so got the count wrong. When actually compiling, the reference

    was subsequently set up correctly.)

15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;

    it was being rejected as not supported by pcre_dfa_exec(), even though

    other assertions are supported. I have made pcre_dfa_exec() support

    (*FAIL).

16. The implementation of 13c above involved the invention of a new opcode,

    OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s

    cannot be changed at match time, I realized I could make a small

    improvement to matching performance by compiling OP_ALLANY instead of

    OP_ANY for "." when DOTALL was set, and then removing the runtime tests

    on the OP_ANY path.

17. Compiling pcretest on Windows with readline support failed without the

    following two fixes: (1) Make the unistd.h include conditional on

    HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.

18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the

    ncurses library to be included for pcretest when ReadLine support is

    requested, but also to allow for it to be overridden. This patch came from

    Daniel Bergstr�m.

19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined

    as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused

    any errors with the current Unicode tables. Thanks to Peter Kankowski for

    spotting this.

Version 7.6 28-Jan-08

---------------------

1.  A character class containing a very large number of characters with

    codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer

    overflow.

2.  Patch to cut out the "long long" test in pcrecpp_unittest when

    HAVE_LONG_LONG is not defined.

3.  Applied Christian Ehrlicher's patch to update the CMake build files to

    bring them up to date and include new features. This patch includes:

    - Fixed PH's badly added libz and libbz2 support.

    - Fixed a problem with static linking.

    - Added pcredemo. [But later removed - see 7 below.]

    - Fixed dftables problem and added an option.

    - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and

        HAVE_LONG_LONG.

    - Added readline support for pcretest.

    - Added an listing of the option settings after cmake has run.

4.  A user submitted a patch to Makefile that makes it easy to create

    "pcre.dll" under mingw when using Configure/Make. I added stuff to

    Makefile.am that cause it to include this special target, without

    affecting anything else. Note that the same mingw target plus all

    the other distribution libraries and programs are now supported

    when configuring with CMake (see 6 below) instead of with

    Configure/Make.

5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.

    This is an attempt to solve the reported problem "pcrecpp::no_arg is not

    exported in the Windows port". It has not yet been confirmed that the patch

    solves the problem, but it does no harm.

6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and

    NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured

    with CMake, and also correct the comment about stack recursion.

7.  Remove the automatic building of pcredemo from the ./configure system and

    from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example

    of a program that users should build themselves after PCRE is installed, so

    building it automatically is not really right. What is more, it gave

    trouble in some build environments.

8.  Further tidies to CMakeLists.txt from Sheri and Christian.

Version 7.5 10-Jan-08

---------------------

1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'

    values in parens when parsing an RE using the C++ wrapper."

2.  Negative specials like \S did not work in character classes in UTF-8 mode.

    Characters greater than 255 were excluded from the class instead of being

    included.

3.  The same bug as (2) above applied to negated POSIX classes such as

    [:^space:].

4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it

    defined or documented. It seems to have been a typo for PCRE_STATIC, so

    I have changed it.

5.  The construct (?&) was not diagnosed as a syntax error (it referenced the

    first named subpattern) and a construct such as (?&a) would reference the

    first named subpattern whose name started with "a" (in other words, the

    length check was missing). Both these problems are fixed. "Subpattern name

    expected" is now given for (?&) (a zero-length name), and this patch also

    makes it give the same error for \k'' (previously it complained that that

    was a reference to a non-existent subpattern).

6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;

    this is right because (?- can be followed by option settings as well as by

    digits. I have, however, made the messages clearer.

7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns

    than the number used in the conditional) now cause a compile-time error.

    This is actually not compatible with Perl, which accepts such patterns, but

    treats the conditional as always being FALSE (as PCRE used to), but it

    seems to me that giving a diagnostic is better.

8.  Change "alphameric" to the more common word "alphanumeric" in comments

    and messages.

9.  Fix two occurrences of "backslash" in comments that should have been

    "backspace".

10. Remove two redundant lines of code that can never be obeyed (their function

    was moved elsewhere).

11. The program that makes PCRE's Unicode character property table had a bug

    which caused it to generate incorrect table entries for sequences of

    characters that have the same character type, but are in different scripts.

    It amalgamated them into a single range, with the script of the first of

    them. In other words, some characters were in the wrong script. There were

    thirteen such cases, affecting characters in the following ranges:

      U+002b0 - U+002c1

      U+0060c - U+0060d

      U+0061e - U+00612

      U+0064b - U+0065e

      U+0074d - U+0076d

      U+01800 - U+01805

      U+01d00 - U+01d77

      U+01d9b - U+01dbf

      U+0200b - U+0200f

      U+030fc - U+030fe

      U+03260 - U+0327f

      U+0fb46 - U+0fbb1

      U+10450 - U+1049d

12. The -o option (show only the matching part of a line) for pcregrep was not

    compatible with GNU grep in that, if there was more than one match in a

    line, it showed only the first of them. It now behaves in the same way as

    GNU grep.

13. If the -o and -v options were combined for pcregrep, it printed a blank

    line for every non-matching line. GNU grep prints nothing, and pcregrep now

    does the same. The return code can be used to tell if there were any

    non-matching lines.

14. Added --file-offsets and --line-offsets to pcregrep.

15. The pattern (?=something)(?R) was not being diagnosed as a potentially

    infinitely looping recursion. The bug was that positive lookaheads were not

    being skipped when checking for a possible empty match (negative lookaheads

    and both kinds of lookbehind were skipped).

16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the

    inclusion of <windows.h> to before rather than after the definition of

    INVALID_FILE_ATTRIBUTES (patch from David Byron).

17. Specifying a possessive quantifier with a specific limit for a Unicode

    character property caused pcre_compile() to compile bad code, which led at

    runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this

    are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that

    caused the error; without that there was no problem.

18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.

19. Added --enable-pcretest-libreadline.

20. In pcrecpp.cc, the variable 'count' was incremented twice in

    RE::GlobalReplace(). As a result, the number of replacements returned was

    double what it should be. I removed one of the increments, but Craig sent a

    later patch that removed the other one (the right fix) and added unit tests

    that check the return values (which was not done before).

21. Several CMake things:

    (1) Arranged that, when cmake is used on Unix, the libraries end up with

        the names libpcre and libpcreposix, not just pcre and pcreposix.

    (2) The above change means that pcretest and pcregrep are now correctly

        linked with the newly-built libraries, not previously installed ones.

    (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.

22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*

    crashed when matching a string such as a\x{2029}b (note that \x{2029} is a

    UTF-8 newline character). The key issue is that the pattern starts .*;

    this means that the match must be either at the beginning, or after a

    newline. The bug was in the code for advancing after a failed match and

    checking that the new position followed a newline. It was not taking

    account of UTF-8 characters correctly.

23. PCRE was behaving differently from Perl in the way it recognized POSIX

    character classes. PCRE was not treating the sequence [:...:] as a

    character class unless the ... were all letters. Perl, however, seems to

    allow any characters between [: and :], though of course it rejects as

    unknown any "names" that contain non-letters, because all the known class

    names consist only of letters. Thus, Perl gives an error for [[:1234:]],

    for example, whereas PCRE did not - it did not recognize a POSIX character

    class. This seemed a bit dangerous, so the code has been changed to be

    closer to Perl. The behaviour is not identical to Perl, because PCRE will

    diagnose an unknown class for, for example, [[:l\ower:]] where Perl will

    treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where

    Perl does, and where it didn't before.

24. Rewrite so as to remove the single use of %n from pcregrep because in some

    Windows environments %n is disabled by default.

Version 7.4 21-Sep-07

---------------------

1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This

    means that a class such as [\s] counted as "explicit reference to CR or

    LF". That isn't really right - the whole point of the change was to try to

    help when there was an actual mention of one of the two characters. So now

    the change happens only if \r or \n (or a literal CR or LF) character is

    encountered.

2.  The 32-bit options word was also used for 6 internal flags, but the numbers

    of both had grown to the point where there were only 3 bits left.

    Fortunately, there was spare space in the data structure, and so I have

    moved the internal flags into a new 16-bit field to free up more option

    bits.

3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,

    but did not set the internal JCHANGED flag - either of these is enough to

    control the way the "get" function works - but the PCRE_INFO_JCHANGED

    facility is supposed to tell if (?J) was ever used, so now (?J) at the

    start sets both bits.

4.  Added options (at build time, compile time, exec time) to change \R from

    matching any Unicode line ending sequence to just matching CR, LF, or CRLF.

5.  doc/pcresyntax.html was missing from the distribution.

6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward

    compatibility, even though it is no longer used.

7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and

    strtoull to pcrecpp.cc to select the available functions in WIN32 when the

    windows.h file is present (where different names are used). [This was

    reversed later after testing - see 16 below.]

8.  Changed all #include <config.h> to #include "config.h". There were also

    some further <pcre.h> cases that I changed to "pcre.h".

9.  When pcregrep was used with the --colour option, it missed the line ending

    sequence off the lines that it output.

10. It was pointed out to me that arrays of string pointers cause lots of

    relocations when a shared library is dynamically loaded. A technique of

    using a single long string with a table of offsets can drastically reduce

    these. I have refactored PCRE in four places to do this. The result is

    dramatic:

      Originally:                          290

      After changing UCP table:            187

      After changing error message table:   43

      After changing table of "verbs"       36

      After changing table of Posix names   22

    Thanks to the folks working on Gregex for glib for this insight.

11. --disable-stack-for-recursion caused compiling to fail unless -enable-

    unicode-properties was also set.

12. Updated the tests so that they work when \R is defaulted to ANYCRLF.

13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously

    checked only for CRLF.

14. Added casts to pcretest.c to avoid compiler warnings.

15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.

16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,

    and instead check for _strtoi64 explicitly, and avoid the use of snprintf()

    entirely. This removes changes made in 7 above.

17. The CMake files have been updated, and there is now more information about

    building with CMake in the NON-UNIX-USE document.

Version 7.3 28-Aug-07

---------------------

 1. In the rejigging of the build system that eventually resulted in 7.1, the

    line "#include <pcre.h>" was included in pcre_internal.h. The use of angle

    brackets there is not right, since it causes compilers to look for an

    installed pcre.h, not the version that is in the source that is being

    compiled (which of course may be different). I have changed it back to:

      #include "pcre.h"

    I have a vague recollection that the change was concerned with compiling in

    different directories, but in the new build system, that is taken care of

    by the VPATH setting the Makefile.

 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed

    when the subject happened to end in the byte 0x85 (e.g. if the last

    character was \x{1ec5}). *Character* 0x85 is one of the "any" newline

    characters but of course it shouldn't be taken as a newline when it is part

    of another character. The bug was that, for an unlimited repeat of . in

    not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by

    characters when looking for a newline.

 3. A small performance improvement in the DOTALL UTF-8 mode .* case.

 4. Debugging: adjusted the names of opcodes for different kinds of parentheses

    in debug output.

 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for

    long printing in the pcrecpp unittest when running under MinGW.

 6. ESC_K was left out of the EBCDIC table.

 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing

    parentheses; I made it 1000, which seemed large enough. Unfortunately, the

    limit also applies to "virtual nesting" when a pattern is recursive, and in

    this case 1000 isn't so big. I have been able to remove this limit at the

    expense of backing off one optimization in certain circumstances. Normally,

    when pcre_exec() would call its internal match() function recursively and

    immediately return the result unconditionally, it uses a "tail recursion"

    feature to save stack. However, when a subpattern that can match an empty

    string has an unlimited repetition quantifier, it no longer makes this

    optimization. That gives it a stack frame in which to save the data for

    checking that an empty string has been matched. Previously this was taken

    from the 1000-entry workspace that had been reserved. So now there is no

    explicit limit, but more stack is used.

 8. Applied Daniel's patches to solve problems with the import/export magic

    syntax that is required for Windows, and which was going wrong for the

    pcreposix and pcrecpp parts of the library. These were overlooked when this

    problem was solved for the main library.

 9. There were some crude static tests to avoid integer overflow when computing

    the size of patterns that contain repeated groups with explicit upper

    limits. As the maximum quantifier is 65535, the maximum group length was

    set at 30,000 so that the product of these two numbers did not overflow a

    32-bit integer. However, it turns out that people want to use groups that

    are longer than 30,000 bytes (though not repeat them that many times).

    Change 7.0/17 (the refactoring of the way the pattern size is computed) has

    made it possible to implement the integer overflow checks in a much more

    dynamic way, which I have now done. The artificial limitation on group

    length has been removed - we now have only the limit on the total length of

    the compiled pattern, which depends on the LINK_SIZE setting.

10. Fixed a bug in the documentation for get/copy named substring when

    duplicate names are permitted. If none of the named substrings are set, the

    functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an

    empty string.

11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E

    instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,

    because the ] is interpreted as the first data character and the

    terminating ] is not found. PCRE has been made compatible with Perl in this

    regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could

    cause memory overwriting.

10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty

    string has been matched (to stop an infinite loop). It was not recognizing

    a conditional subpattern that could match an empty string if that

    subpattern was within another subpattern. For example, it looped when

    trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the

    condition was not nested. This bug has been fixed.

12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack

    past the start of the subject in the presence of bytes with the top bit

    set, for example "\x8aBCD".

13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),

    (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).

14. Optimized (?!) to (*FAIL).

15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.

    This restricts code points to be within the range 0 to 0x10FFFF, excluding

    the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the

    full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still

    does: it's just the validity check that is more restrictive.

16. Inserted checks for integer overflows during escape sequence (backslash)

    processing, and also fixed erroneous offset values for syntax errors during

    backslash processing.

17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)

    for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".

18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"

    caused an overrun.

19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with

    something other than just ASCII characters) inside a group that had an

    unlimited repeat caused a loop at compile time (while checking to see

    whether the group could match an empty string).

20. Debugging a pattern containing \p or \P could cause a crash. For example,

    [\P{Any}] did so. (Error in the code for printing property names.)

21. An orphan \E inside a character class could cause a crash.

22. A repeated capturing bracket such as (A)? could cause a wild memory

    reference during compilation.

23. There are several functions in pcre_compile() that scan along a compiled

    expression for various reasons (e.g. to see if it's fixed length for look

    behind). There were bugs in these functions when a repeated \p or \P was

    present in the pattern. These operators have additional parameters compared

    with \d, etc, and these were not being taken into account when moving along

    the compiled data. Specifically:

    (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed

        length.

    (b) An item such as \pL+ within a repeated group could cause crashes or

        loops.

    (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect

        "reference to non-existent subpattern" error.

    (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.

24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte

    characters were involved (for example /\S{2}/8g with "A\x{a3}BC").

25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.

26. Patterns such as [\P{Yi}A] which include \p or \P and just one other

    character were causing crashes (broken optimization).

27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing

    \p or \P) caused a compile-time loop.

28. More problems have arisen in unanchored patterns when CRLF is a valid line

    break. For example, the unstudied pattern [\r\n]A does not match the string

    "\r\nA" because change 7.0/46 below moves the current point on by two

    characters after failing to match at the start. However, the pattern \nA

    *does* match, because it doesn't start till \n, and if [\r\n]A is studied,

    the same is true. There doesn't seem any very clean way out of this, but

    what I have chosen to do makes the common cases work: PCRE now takes note

    of whether there can be an explicit match for \r or \n anywhere in the

    pattern, and if so, 7.0/46 no longer applies. As part of this change,

    there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled

    pattern has explicit CR or LF references.

29. Added (*CR) etc for changing newline setting at start of pattern.

Version 7.2 19-Jun-07

---------------------

 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,

    which is apparently normally available under Windows.

 2. Re-jig the pcregrep tests with different newline settings in an attempt

    to make them independent of the local environment's newline setting.

 3. Add code to configure.ac to remove -g from the CFLAGS default settings.

 4. Some of the "internals" tests were previously cut out when the link size

    was not 2, because the output contained actual offsets. The recent new

    "Z" feature of pcretest means that these can be cut out, making the tests

    usable with all link sizes.

 5. Implemented Stan Switzer's goto replacement for longjmp() when not using

    stack recursion. This gives a massive performance boost under BSD, but just

    a small improvement under Linux. However, it saves one field in the frame

    in all cases.

 6. Added more features from the forthcoming Perl 5.10:

    (a) (?-n) (where n is a string of digits) is a relative subroutine or

        recursion call. It refers to the nth most recently opened parentheses.

    (b) (?+n) is also a relative subroutine call; it refers to the nth next

        to be opened parentheses.

    (c) Conditions that refer to capturing parentheses can be specified

        relatively, for example, (?(-2)... or (?(+3)...

    (d) \K resets the start of the current match so that everything before

        is not part of it.

    (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).

    (f) \g{name} is another synonym - part of Perl 5.10's unification of

        reference syntax.

    (g) (?| introduces a group in which the numbering of parentheses in each

        alternative starts with the same number.

    (h) \h, \H, \v, and \V match horizontal and vertical whitespace.

 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and

    PCRE_INFO_JCHANGED.

 8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not

    terminating or by crashing. Diagnosed by Viktor Griph; it was in the code

    for detecting groups that can match an empty string.

 9. A pattern with a very large number of alternatives (more than several

    hundred) was running out of internal workspace during the pre-compile

    phase, where pcre_compile() figures out how much memory will be needed. A

    bit of new cunning has reduced the workspace needed for groups with

    alternatives. The 1000-alternative test pattern now uses 12 bytes of

    workspace instead of running out of the 4096 that are available.

10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.

11. Applied patch from Google to remove an optimization that didn't quite work.

    The report of the bug said:

      pcrecpp::RE("a*").FullMatch("aaa") matches, while

      pcrecpp::RE("a*?").FullMatch("aaa") does not, and

      pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.

12. If \p or \P was used in non-UTF-8 mode on a character greater than 127

    it matched the wrong number of bytes.

Version 7.1 24-Apr-07

---------------------

 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one

    that is more "standard", making use of automake and other Autotools. There

    is some re-arrangement of the files and adjustment of comments consequent

    on this.

 2. Part of the patch fixed a problem with the pcregrep tests. The test of -r

    for recursive directory scanning broke on some systems because the files

    are not scanned in any specific order and on different systems the order

    was different. A call to "sort" has been inserted into RunGrepTest for the

    approprate test as a short-term fix. In the longer term there may be an

    alternative.

 3. I had an email from Eric Raymond about problems translating some of PCRE's

    man pages to HTML (despite the fact that I distribute HTML pages, some

    people do their own conversions for various reasons). The problems

    concerned the use of low-level troff macros .br and .in. I have therefore

    removed all such uses from the man pages (some were redundant, some could

    be replaced by .nf/.fi pairs). The 132html script that I use to generate

    HTML has been updated to handle .nf/.fi and to complain if it encounters

    .br or .in.

 4. Updated comments in configure.ac that get placed in config.h.in and also

    arranged for config.h to be included in the distribution, with the name

    config.h.generic, for the benefit of those who have to compile without

    Autotools (compare pcre.h, which is now distributed as pcre.h.generic).

 5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan

    Weber: (1) pcre_internal.h was missing some function renames; (2) updated

    makevp.bat for the current PCRE, using the additional files

    makevp_c.txt, makevp_l.txt, and pcregexp.pas.

 6. A Windows user reported a minor discrepancy with test 2, which turned out

    to be caused by a trailing space on an input line that had got lost in his

    copy. The trailing space was an accident, so I've just removed it.

 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told

    that is needed.

 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)

    as "const" (a) because they are and (b) because it helps the PHP

    maintainers who have recently made a script to detect big data structures

    in the php code that should be moved to the .rodata section. I remembered

    to update Builducptable as well, so it won't revert if ucptable.h is ever

    re-created.

 9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,

    pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in

    order to be able to cut out the UTF-8 tables in the latter when UTF-8

    support is not required. This saves 1.5-2K of code, which is important in

    some applications.

    Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c

    so as not to refer to the tables, even though these functions will never be

    called when UTF-8 support is disabled. Otherwise there are problems with a

    shared library.

10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:

    (a) It was defining its arguments as char * instead of void *.

    (b) It was assuming that all moves were upwards in memory; this was true

        a long time ago when I wrote it, but is no longer the case.

    The emulated memove() is provided for those environments that have neither

    memmove() nor bcopy(). I didn't think anyone used it these days, but that

    is clearly not the case, as these two bugs were recently reported.

11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,

    and Detrail to create the HTML documentation, the .txt form of the man

    pages, and it removes trailing spaces from listed files. It also creates

    pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter

    case, it wraps all the #defines with #ifndefs. This script should be run

    before "make dist".

12. Fixed two fairly obscure bugs concerned with quantified caseless matching

    with Unicode property support.

    (a) For a maximizing quantifier, if the two different cases of the

        character were of different lengths in their UTF-8 codings (there are

        some cases like this - I found 11), and the matching function had to

        back up over a mixture of the two cases, it incorrectly assumed they

        were both the same length.

    (b) When PCRE was configured to use the heap rather than the stack for

        recursion during matching, it was not correctly preserving the data for

        the other case of a UTF-8 character when checking ahead for a match

        while processing a minimizing repeat. If the check also involved

        matching a wide character, but failed, corruption could cause an

        erroneous result when trying to check for a repeat of the original

        character.

13. Some tidying changes to the testing mechanism:

    (a) The RunTest script now detects the internal link size and whether there

        is UTF-8 and UCP support by running ./pcretest -C instead of relying on

        values substituted by "configure". (The RunGrepTest script already did

        this for UTF-8.) The configure.ac script no longer substitutes the

        relevant variables.

    (b) The debugging options /B and /D in pcretest show the compiled bytecode

        with length and offset values. This means that the output is different

        for different internal link sizes. Test 2 is skipped for link sizes

        other than 2 because of this, bypassing the problem. Unfortunately,

        there was also a test in test 3 (the locale tests) that used /B and

        failed for link sizes other than 2. Rather than cut the whole test out,

        I have added a new /Z option to pcretest that replaces the length and

        offset values with spaces. This is now used to make test 3 independent

        of link size. (Test 2 will be tidied up later.)

14. If erroroffset was passed as NULL to pcre_compile, it provoked a

    segmentation fault instead of returning the appropriate error message.

15. In multiline mode when the newline sequence was set to "any", the pattern

    ^$ would give a match between the \r and \n of a subject such as "A\r\nB".

    This doesn't seem right; it now treats the CRLF combination as the line

    ending, and so does not match in that case. It's only a pattern such as ^$

    that would hit this one: something like ^ABC$ would have failed after \r

    and then tried again after \r\n.

16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"

    in an attempt to make files that differ only in their line terminators

    compare equal. This works on Linux.

17. Under certain error circumstances pcregrep might try to free random memory

    as it exited. This is now fixed, thanks to valgrind.

19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string

    "abc\r\n\r\n", it found an unwanted second match after the second \r. This

    was because its rules for how to advance for /g after matching an empty

    string at the end of a line did not allow for this case. They now check for

    it specially.

20. pcretest is supposed to handle patterns and data of any length, by

    extending its buffers when necessary. It was getting this wrong when the

    buffer for a data line had to be extended.

21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or

    CRLF as a newline sequence.

22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut

    out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but

    I have nevertheless tidied it up.

23. Added some casts to kill warnings from HP-UX ia64 compiler.

24. Added a man page for pcre-config.

Version 7.0 19-Dec-06

---------------------

 1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by