80 lines
3.8 KiB
Plaintext
80 lines
3.8 KiB
Plaintext
Change Log for PCRE2
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--------------------
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Version 10.10 13-January-2015
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-----------------------------
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1. When a pattern is compiled, it remembers the highest back reference so that
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when matching, if the ovector is too small, extra memory can be obtained to
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use instead. A conditional subpattern whose condition is a check on a capture
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having happened, such as, for example in the pattern /^(?:(a)|b)(?(1)A|B)/, is
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another kind of back reference, but it was not setting the highest
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backreference number. This mattered only if pcre2_match() was called with an
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ovector that was too small to hold the capture, and there was no other kind of
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back reference (a situation which is probably quite rare). The effect of the
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bug was that the condition was always treated as FALSE when the capture could
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not be consulted, leading to a incorrect behaviour by pcre2_match(). This bug
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has been fixed.
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Version 10.00 05-January-2015
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-----------------------------
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Version 10.00 is the first release of PCRE2, a revised API for the PCRE
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library. Changes prior to 10.00 are logged in the ChangeLog file for the old
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API, up to item 20 for release 8.36.
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The code of the library was heavily revised as part of the new API
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implementation. Details of each and every modification were not individually
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logged. In addition to the API changes, the following changes were made. They
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are either new functionality, or bug fixes and other noticeable changes of
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behaviour that were implemented after the code had been forked.
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1. Unicode support is now enabled by default, but it can optionally be
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disabled.
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2. The test program, now called pcre2test, was re-specified and almost
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completely re-written. Its input is not compatible with input for pcretest.
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3. Patterns may start with (*NOTEMPTY) or (*NOTEMPTY_ATSTART) to set the
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PCRE2_NOTEMPTY or PCRE2_NOTEMPTY_ATSTART options for every subject line that is
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matched by that pattern.
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4. For the benefit of those who use PCRE2 via some other application, that is,
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not writing the function calls themselves, it is possible to check the PCRE2
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version by matching a pattern such as /(?(VERSION>=10)yes|no)/ against a
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string such as "yesno".
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5. There are case-equivalent Unicode characters whose encodings use different
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numbers of code units in UTF-8. U+023A and U+2C65 are one example. (It is
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theoretically possible for this to happen in UTF-16 too.) If a backreference to
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a group containing one of these characters was greedily repeated, and during
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the match a backtrack occurred, the subject might be backtracked by the wrong
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number of code units. For example, if /^(\x{23a})\1*(.)/ is matched caselessly
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(and in UTF-8 mode) against "\x{23a}\x{2c65}\x{2c65}\x{2c65}", group 2 should
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capture the final character, which is the three bytes E2, B1, and A5 in UTF-8.
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Incorrect backtracking meant that group 2 captured only the last two bytes.
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This bug has been fixed; the new code is slower, but it is used only when the
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strings matched by the repetition are not all the same length.
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6. A pattern such as /()a/ was not setting the "first character must be 'a'"
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information. This applied to any pattern with a group that matched no
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characters, for example: /(?:(?=.)|(?<!x))a/.
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7. When an (*ACCEPT) is triggered inside capturing parentheses, it arranges for
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those parentheses to be closed with whatever has been captured so far. However,
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it was failing to mark any other groups between the highest capture so far and
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the currrent group as "unset". Thus, the ovector for those groups contained
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whatever was previously there. An example is the pattern /(x)|((*ACCEPT))/ when
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matched against "abcd".
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8. The pcre2_substitute() function has been implemented.
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9. If an assertion used as a condition was quantified with a minimum of zero
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(an odd thing to do, but it happened), SIGSEGV or other misbehaviour could
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occur.
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10. The PCRE2_NO_DOTSTAR_ANCHOR option has been implemented.
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****
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