diff options
| author | Alexander Barkov <bar@mnogosearch.org> | 2013-09-26 18:02:17 +0400 |
|---|---|---|
| committer | Alexander Barkov <bar@mnogosearch.org> | 2013-09-26 18:02:17 +0400 |
| commit | 285e7aa179a6081531be3274772b89e8989fd107 (patch) | |
| tree | 71836ea6e49f48fff6e957bcef38628e7b979001 /pcre/doc/html/pcrelimits.html | |
| parent | 9d83468e78ba23f024ce3c11443913ad75cf1ea5 (diff) | |
| download | mariadb-git-285e7aa179a6081531be3274772b89e8989fd107.tar.gz | |
MDEV-4425 REGEXP enhancements
Diffstat (limited to 'pcre/doc/html/pcrelimits.html')
| -rw-r--r-- | pcre/doc/html/pcrelimits.html | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/pcre/doc/html/pcrelimits.html b/pcre/doc/html/pcrelimits.html new file mode 100644 index 00000000000..b83a801040a --- /dev/null +++ b/pcre/doc/html/pcrelimits.html @@ -0,0 +1,86 @@ +<html> +<head> +<title>pcrelimits specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrelimits man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SIZE AND OTHER LIMITATIONS +</b><br> +<P> +There are some size limitations in PCRE but it is hoped that they will never in +practice be relevant. +</P> +<P> +The maximum length of a compiled pattern is approximately 64K data units (bytes +for the 8-bit library, 32-bit units for the 32-bit library, and 32-bit units for +the 32-bit library) if PCRE is compiled with the default internal linkage size +of 2 bytes. If you want to process regular expressions that are truly enormous, +you can compile PCRE with an internal linkage size of 3 or 4 (when building the +16-bit or 32-bit library, 3 is rounded up to 4). See the <b>README</b> file in +the source distribution and the +<a href="pcrebuild.html"><b>pcrebuild</b></a> +documentation for details. In these cases the limit is substantially larger. +However, the speed of execution is slower. +</P> +<P> +All values in repeating quantifiers must be less than 65536. +</P> +<P> +There is no limit to the number of parenthesized subpatterns, but there can be +no more than 65535 capturing subpatterns. +</P> +<P> +There is a limit to the number of forward references to subsequent subpatterns +of around 200,000. Repeated forward references with fixed upper limits, for +example, (?2){0,100} when subpattern number 2 is to the right, are included in +the count. There is no limit to the number of backward references. +</P> +<P> +The maximum length of name for a named subpattern is 32 characters, and the +maximum number of named subpatterns is 10000. +</P> +<P> +The maximum length of a name in a (*MARK), (*PRUNE), (*SKIP), or (*THEN) verb +is 255 for the 8-bit library and 65535 for the 16-bit and 32-bit library. +</P> +<P> +The maximum length of a subject string is the largest positive number that an +integer variable can hold. However, when using the traditional matching +function, PCRE uses recursion to handle subpatterns and indefinite repetition. +This means that the available stack space may limit the size of a subject +string that can be processed by certain patterns. For a discussion of stack +issues, see the +<a href="pcrestack.html"><b>pcrestack</b></a> +documentation. +</P> +<br><b> +AUTHOR +</b><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><b> +REVISION +</b><br> +<P> +Last updated: 04 May 2012 +<br> +Copyright © 1997-2012 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> |