new upstream release (3.3.0); modify package compatibility for Stretch

[ossec-hids.git] / src / external / pcre2-10.32 / doc / pcre2limits.3

diff --git a/src/external/pcre2-10.32/doc/pcre2limits.3 b/src/external/pcre2-10.32/doc/pcre2limits.3
new file mode 100644 (file)
index 0000000..803e97b
--- /dev/null
+++ b/src/external/pcre2-10.32/doc/pcre2limits.3
@@ -0,0 +1,72 @@
+.TH PCRE2LIMITS 3 "30 March 2017" "PCRE2 10.30"
+.SH NAME
+PCRE2 - Perl-compatible regular expressions (revised API)
+.SH "SIZE AND OTHER LIMITATIONS"
+.rs
+.sp
+There are some size limitations in PCRE2 but it is hoped that they will never
+in practice be relevant.
+.P
+The maximum size of a compiled pattern is approximately 64 thousand code units
+for the 8-bit and 16-bit libraries if PCRE2 is compiled with the default
+internal linkage size, which is 2 bytes for these libraries. If you want to
+process regular expressions that are truly enormous, you can compile PCRE2 with
+an internal linkage size of 3 or 4 (when building the 16-bit library, 3 is
+rounded up to 4). See the \fBREADME\fP file in the source distribution and the
+.\" HREF
+\fBpcre2build\fP
+.\"
+documentation for details. In these cases the limit is substantially larger.
+However, the speed of execution is slower. In the 32-bit library, the internal
+linkage size is always 4.
+.P
+The maximum length of a source pattern string is essentially unlimited; it is
+the largest number a PCRE2_SIZE variable can hold. However, the program that
+calls \fBpcre2_compile()\fP can specify a smaller limit.
+.P
+The maximum length (in code units) of a subject string is one less than the
+largest number a PCRE2_SIZE variable can hold. PCRE2_SIZE is an unsigned
+integer type, usually defined as size_t. Its maximum value (that is
+~(PCRE2_SIZE)0) is reserved as a special indicator for zero-terminated strings
+and unset offsets.
+.P
+All values in repeating quantifiers must be less than 65536.
+.P
+The maximum length of a lookbehind assertion is 65535 characters.
+.P
+There is no limit to the number of parenthesized subpatterns, but there can be
+no more than 65535 capturing subpatterns. There is, however, a limit to the
+depth of nesting of parenthesized subpatterns of all kinds. This is imposed in
+order to limit the amount of system stack used at compile time. The default
+limit can be specified when PCRE2 is built; if not, the default is set to 250.
+An application can change this limit by calling pcre2_set_parens_nest_limit()
+to set the limit in a compile context.
+.P
+The maximum length of name for a named subpattern is 32 code units, and the
+maximum number of named subpatterns is 10000.
+.P
+The maximum length of a name in a (*MARK), (*PRUNE), (*SKIP), or (*THEN) verb
+is 255 code units for the 8-bit library and 65535 code units for the 16-bit and
+32-bit libraries.
+.P
+The maximum length of a string argument to a callout is the largest number a
+32-bit unsigned integer can hold.
+.
+.
+.SH AUTHOR
+.rs
+.sp
+.nf
+Philip Hazel
+University Computing Service
+Cambridge, England.
+.fi
+.
+.
+.SH REVISION
+.rs
+.sp
+.nf
+Last updated: 30 March 2017
+Copyright (c) 1997-2017 University of Cambridge.
+.fi