NAME

re::engine::PCRE2 - PCRE2 regular expression engine with jit

SYNOPSIS

use re::engine::PCRE2;

if ("Hello, world" =~ /(?<=Hello|Hi), (world)/) {
    print "Greetings, $1!";
}

DESCRIPTION

Replaces perl's regex engine in a given lexical scope with PCRE2 regular expressions provided by libpcre2-8.

This provides jit support and faster matching, but may fail in corner cases. See pcre2compat. It is typically 10% faster then the core regex engine.

Note that some packaged libpcre2-8 libraries do not enable the jit compiler. CFLAGS=-fPIC cmake -DPCRE2_SUPPORT_JIT=ON; make PCRE2 then silently falls back to the normal PCRE2 compiler and matcher.

Check with:

perl -Mre::engine::PCRE2 -e'print re::engine::PCRE2::JIT'

METHODS

Since re::engine::PCRE2 derives from the Regexp package, you can call compiled qr// objects with these methods. See PCRE2 NATIVE API MATCH CONTEXT FUNCTIONS and INFORMATION ABOUT A COMPILED PATTERN

• match_limit (RX, [INT])

  Get or set the match_limit match context. NYI

• offset_limit (RX, [INT])

  NYI

• recursion_limit (RX, [INT])

  NYI

• _alloptions (RX)

  The result of pcre2_pattern_info(PCRE2_INFO_ALLOPTIONS) as unsigned integer.

    my $q=qr/(a)/; print $q->_alloptions
    => 64
  

  64 stands for PCRE2_DUPNAMES which is always set. See pcre2.h

• _argoptions (RX)

  The result of pcre2_pattern_info(PCRE2_INFO_ARGOPTIONS) as unsigned integer.

    my $q=qr/(a)/i; print $q->_argoptions
    => 72
  

  72 = 64+8 64 stands for PCRE2_DUPNAMES which is always set. 8 for PCRE2_CASELESS. See pcre2.h

• backrefmax (RX)

  Return the number of the highest back reference in the pattern.

    my $q=qr/(a)\1/; print $q->backrefmax
    => 1
    my $q=qr/(a)(?(1)a|b)/; print $q->backrefmax
    => 1
  

• bsr (RX)

  What character sequences the \R escape sequence matches. 1 means that \R matches any Unicode line ending sequence; 2 means that \R matches only CR, LF, or CRLF.

• capturecount (RX)

  Return the highest capturing subpattern number in the pattern. In patterns where (?| is not used, this is also the total number of capturing subpatterns.

    my $q=qr/(a(b))/; print $q->capturecount
    => 2
  

• firstbitmap (RX)

  In the absence of a single first code unit for a non-anchored pattern, pcre2_compile() may construct a 256-bit table that defines a fixed set of values for the first code unit in any match. For example, a pattern that starts with [abc] results in a table with three bits set. When code unit values greater than 255 are supported, the flag bit for 255 means "any code unit of value 255 or above". If such a table was constructed, it is returned as string.

• firstcodetype (RX)

  Return information about the first code unit of any matched string, for a non-anchored pattern. If there is a fixed first value, for example, the letter "c" from a pattern such as (cat|cow|coyote), 1 is returned, and the character value can be retrieved using "firstcodeunit". If there is no fixed first value, but it is known that a match can occur only at the start of the subject or following a newline in the subject, 2 is returned. Otherwise, and for anchored patterns, 0 is returned.

• firstcodeunit (RX)

  Return the value of the first code unit of any matched string in the situation where "firstcodetype (RX)" returns 1; otherwise return 0. The value is always less than 256.

    my $q=qr/(cat|cow|coyote)/; print $q->firstcodetype, $q->firstcodeunit
    => 1 99
  

• hasbackslashc (RX)

  Return 1 if the pattern contains any instances of \C, otherwise 0. Note that \C is forbidden since perl 5.26 (?).

• hascrorlf (RX)

  Return 1 if the pattern contains any explicit matches for CR or LF characters, otherwise 0. An explicit match is either a literal CR or LF character, or \r or \n.

• jchanged (RX)

  Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise 0. (?J) and (?-J) set and unset the local PCRE2_DUPNAMES option, respectively.

• jitsize (RX)

  If the compiled pattern was successfully processed by pcre2_jit_compile(), return the size of the JIT compiled code, otherwise return zero.

• lastcodetype (RX)

  Returns 1 if there is a rightmost literal code unit that must exist in any matched string, other than at its start. If there is no such value, 0 is returned. When 1 is returned, the code unit value itself can be retrieved using "lastcodeunit (RX)". For anchored patterns, a last literal value is recorded only if it follows something of variable length. For example, for the pattern /^a\d+z\d+/ the returned value is 1 (with "z" returned from lastcodeunit), but for /^a\dz\d/ the returned value is 0.

• lastcodeunit (RX)

  Return the value of the rightmost literal data unit that must exist in any matched string, other than at its start, if such a value has been recorded. The third argument should point to an uint32_t variable. If there is no such value, 0 is returned.

• matchempty (RX)

  Return 1 if the pattern might match an empty string, otherwise 0. The third argument should point to an uint32_t variable. When a pattern contains recursive subroutine calls it is not always possible to determine whether or not it can match an empty string. PCRE2 takes a cautious approach and returns 1 in such cases.

• matchlimit (RX)

  If the pattern set a match limit by including an item of the form (*LIMIT_MATCH=nnnn) at the start, the value is returned.

• maxlookbehind (RX)

  Return the number of characters (not code units) in the longest lookbehind assertion in the pattern. The third argument should point to an unsigned 32-bit integer. This information is useful when doing multi-segment matching using the partial matching facilities. Note that the simple assertions \b and \B require a one-character lookbehind. \A also registers a one-character lookbehind, though it does not actually inspect the previous character. This is to ensure that at least one character from the old segment is retained when a new segment is processed. Otherwise, if there are no lookbehinds in the pattern, \A might match incorrectly at the start of a new segment.

• minlength (RX)

  If a minimum length for matching subject strings was computed, its value is returned. Otherwise the returned value is 0. The value is a number of characters, which in UTF mode may be different from the number of code units. The third argument should point to an uint32_t variable. The value is a lower bound to the length of any matching string. There may not be any strings of that length that do actually match, but every string that does match is at least that long.

• namecount (RX)

• nameentrysize (RX)

  PCRE2 supports the use of named as well as numbered capturing parentheses. The names are just an additional way of identifying the parentheses, which still acquire numbers. Several convenience functions such as pcre2_substring_get_byname() are provided for extracting captured substrings by name. It is also possible to extract the data directly, by first converting the name to a number in order to access the correct pointers in the output vector. To do the conversion, you need to use the name-to-number map, which is described by these three values.

  The map consists of a number of fixed-size entries. namecount gives the number of entries, and nameentrysize gives the size of each entry in code units; The entry size depends on the length of the longest name.

  The nametable itself is not yet returned.

• newline (RX)

  Returns the newline regime, see below at "config (OPTION)".

• recursionlimit (RX)

  If the pattern set a recursion limit by including an item of the form (*LIMIT_RECURSION=nnnn) at the start, the value is returned.

• size (RX)

  Return the size of the compiled pattern in bytes (for all three libraries). The third argument should point to a size_t variable. This value includes the size of the general data block that precedes the code units of the compiled pattern itself. The value that is used when pcre2_compile() is getting memory in which to place the compiled pattern may be slightly larger than the value returned by this option, because there are cases where the code that calculates the size has to over-estimate. Processing a pattern with the JIT compiler does not alter the value returned by this option.

FUNCTIONS

• import

  import lexically sets the PCRE2 engine to be active.

  import will later accept compile context options. See PCRE2 NATIVE API COMPILE CONTEXT FUNCTIONS.

    bsr => INT
    max_pattern_length => INT
    newline => INT
    parens_nest_limit => INT
  
    match_limit => INT
    offset_limit => INT
    recursion_limit => INT
  

• unimport

  unimport sets the regex engine to the previous one. If PCRE2 with the previous context options.

• ENGINE

  Returns a pointer to the internal PCRE2 engine, suitable for the XS API (regexp*)re->engine field.

• JIT

  Returns 1 or 0, if the JIT engine is available or not.

• config (OPTION)

  Returns build-time information about libpcre2. Note that some of these options may later be set'able at run-time.

  OPTIONS can be one of the following strings:

    JITTARGET
    UNICODE_VERSION
    VERSION
  
    BSR
    JIT
    LINKSIZE
    MATCHLIMIT
    NEWLINE
    PARENSLIMIT
    DEPTHLIMIT
    RECURSIONLIMIT
    STACKRECURSE
    UNICODE
  

  The first three options return a string, the rest an integer. See http://www.pcre.org/current/doc/html/pcre2api.html#SEC17.

  NEWLINE returns an integer, representing:

    PCRE2_NEWLINE_CR          1
    PCRE2_NEWLINE_LF          2
    PCRE2_NEWLINE_CRLF        3
    PCRE2_NEWLINE_ANY         4  Any Unicode line ending
    PCRE2_NEWLINE_ANYCRLF     5  Any of CR, LF, or CRLF
  

  The default is OS specific.

  BSR returns an integer, representing:

    PCRE2_BSR_UNICODE         1
    PCRE2_BSR_ANYCRLF         2
  

  A value of PCRE2_BSR_UNICODE means that \R matches any Unicode line ending sequence; a value of PCRE2_BSR_ANYCRLF means that \R matches only CR, LF, or CRLF.

  The default is 1 for UNICODE, as all libpcre2 libraries are now compiled with unicode support builtin. (--enable-unicode).

AUTHORS

Reini Urban rurban@cpan.org

COPYRIGHT

Copyright 2007 Ævar Arnfjörð Bjarmason. Copyright 2017 Reini Urban.

The original version was copyright 2006 Audrey Tang cpan@audreyt.org and Yves Orton.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.