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diff --git a/plugins/Pcre16/docs/doc/pcreunicode.3 b/plugins/Pcre16/docs/doc/pcreunicode.3 deleted file mode 100644 index cb5e5269a4..0000000000 --- a/plugins/Pcre16/docs/doc/pcreunicode.3 +++ /dev/null @@ -1,249 +0,0 @@ -.TH PCREUNICODE 3 "27 February 2013" "PCRE 8.33" -.SH NAME -PCRE - Perl-compatible regular expressions -.SH "UTF-8, UTF-16, UTF-32, AND UNICODE PROPERTY SUPPORT" -.rs -.sp -As well as UTF-8 support, PCRE also supports UTF-16 (from release 8.30) and -UTF-32 (from release 8.32), by means of two additional libraries. They can be -built as well as, or instead of, the 8-bit library. -. -. -.SH "UTF-8 SUPPORT" -.rs -.sp -In order process UTF-8 strings, you must build PCRE's 8-bit library with UTF -support, and, in addition, you must call -.\" HREF -\fBpcre_compile()\fP -.\" -with the PCRE_UTF8 option flag, or the pattern must start with the sequence -(*UTF8) or (*UTF). When either of these is the case, both the pattern and any -subject strings that are matched against it are treated as UTF-8 strings -instead of strings of individual 1-byte characters. -. -. -.SH "UTF-16 AND UTF-32 SUPPORT" -.rs -.sp -In order process UTF-16 or UTF-32 strings, you must build PCRE's 16-bit or -32-bit library with UTF support, and, in addition, you must call -.\" HREF -\fBpcre16_compile()\fP -.\" -or -.\" HREF -\fBpcre32_compile()\fP -.\" -with the PCRE_UTF16 or PCRE_UTF32 option flag, as appropriate. Alternatively, -the pattern must start with the sequence (*UTF16), (*UTF32), as appropriate, or -(*UTF), which can be used with either library. When UTF mode is set, both the -pattern and any subject strings that are matched against it are treated as -UTF-16 or UTF-32 strings instead of strings of individual 16-bit or 32-bit -characters. -. -. -.SH "UTF SUPPORT OVERHEAD" -.rs -.sp -If you compile PCRE with UTF support, but do not use it at run time, the -library will be a bit bigger, but the additional run time overhead is limited -to testing the PCRE_UTF[8|16|32] flag occasionally, so should not be very big. -. -. -.SH "UNICODE PROPERTY SUPPORT" -.rs -.sp -If PCRE is built with Unicode character property support (which implies UTF -support), the escape sequences \ep{..}, \eP{..}, and \eX can be used. -The available properties that can be tested are limited to the general -category properties such as Lu for an upper case letter or Nd for a decimal -number, the Unicode script names such as Arabic or Han, and the derived -properties Any and L&. Full lists is given in the -.\" HREF -\fBpcrepattern\fP -.\" -and -.\" HREF -\fBpcresyntax\fP -.\" -documentation. Only the short names for properties are supported. For example, -\ep{L} matches a letter. Its Perl synonym, \ep{Letter}, is not supported. -Furthermore, in Perl, many properties may optionally be prefixed by "Is", for -compatibility with Perl 5.6. PCRE does not support this. -. -. -.\" HTML <a name="utf8strings"></a> -.SS "Validity of UTF-8 strings" -.rs -.sp -When you set the PCRE_UTF8 flag, the byte strings passed as patterns and -subjects are (by default) checked for validity on entry to the relevant -functions. The entire string is checked before any other processing takes -place. From release 7.3 of PCRE, the check is according the rules of RFC 3629, -which are themselves derived from the Unicode specification. Earlier releases -of PCRE followed the rules of RFC 2279, which allows the full range of 31-bit -values (0 to 0x7FFFFFFF). The current check allows only values in the range U+0 -to U+10FFFF, excluding the surrogate area. (From release 8.33 the so-called -"non-character" code points are no longer excluded because Unicode corrigendum -#9 makes it clear that they should not be.) -.P -Characters in the "Surrogate Area" of Unicode are reserved for use by UTF-16, -where they are used in pairs to encode codepoints with values greater than -0xFFFF. The code points that are encoded by UTF-16 pairs are available -independently in the UTF-8 and UTF-32 encodings. (In other words, the whole -surrogate thing is a fudge for UTF-16 which unfortunately messes up UTF-8 and -UTF-32.) -.P -If an invalid UTF-8 string is passed to PCRE, an error return is given. At -compile time, the only additional information is the offset to the first byte -of the failing character. The run-time functions \fBpcre_exec()\fP and -\fBpcre_dfa_exec()\fP also pass back this information, as well as a more -detailed reason code if the caller has provided memory in which to do this. -.P -In some situations, you may already know that your strings are valid, and -therefore want to skip these checks in order to improve performance, for -example in the case of a long subject string that is being scanned repeatedly. -If you set the PCRE_NO_UTF8_CHECK flag at compile time or at run time, PCRE -assumes that the pattern or subject it is given (respectively) contains only -valid UTF-8 codes. In this case, it does not diagnose an invalid UTF-8 string. -.P -Note that passing PCRE_NO_UTF8_CHECK to \fBpcre_compile()\fP just disables the -check for the pattern; it does not also apply to subject strings. If you want -to disable the check for a subject string you must pass this option to -\fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. -.P -If you pass an invalid UTF-8 string when PCRE_NO_UTF8_CHECK is set, the result -is undefined and your program may crash. -. -. -.\" HTML <a name="utf16strings"></a> -.SS "Validity of UTF-16 strings" -.rs -.sp -When you set the PCRE_UTF16 flag, the strings of 16-bit data units that are -passed as patterns and subjects are (by default) checked for validity on entry -to the relevant functions. Values other than those in the surrogate range -U+D800 to U+DFFF are independent code points. Values in the surrogate range -must be used in pairs in the correct manner. -.P -If an invalid UTF-16 string is passed to PCRE, an error return is given. At -compile time, the only additional information is the offset to the first data -unit of the failing character. The run-time functions \fBpcre16_exec()\fP and -\fBpcre16_dfa_exec()\fP also pass back this information, as well as a more -detailed reason code if the caller has provided memory in which to do this. -.P -In some situations, you may already know that your strings are valid, and -therefore want to skip these checks in order to improve performance. If you set -the PCRE_NO_UTF16_CHECK flag at compile time or at run time, PCRE assumes that -the pattern or subject it is given (respectively) contains only valid UTF-16 -sequences. In this case, it does not diagnose an invalid UTF-16 string. -However, if an invalid string is passed, the result is undefined. -. -. -.\" HTML <a name="utf32strings"></a> -.SS "Validity of UTF-32 strings" -.rs -.sp -When you set the PCRE_UTF32 flag, the strings of 32-bit data units that are -passed as patterns and subjects are (by default) checked for validity on entry -to the relevant functions. This check allows only values in the range U+0 -to U+10FFFF, excluding the surrogate area U+D800 to U+DFFF. -.P -If an invalid UTF-32 string is passed to PCRE, an error return is given. At -compile time, the only additional information is the offset to the first data -unit of the failing character. The run-time functions \fBpcre32_exec()\fP and -\fBpcre32_dfa_exec()\fP also pass back this information, as well as a more -detailed reason code if the caller has provided memory in which to do this. -.P -In some situations, you may already know that your strings are valid, and -therefore want to skip these checks in order to improve performance. If you set -the PCRE_NO_UTF32_CHECK flag at compile time or at run time, PCRE assumes that -the pattern or subject it is given (respectively) contains only valid UTF-32 -sequences. In this case, it does not diagnose an invalid UTF-32 string. -However, if an invalid string is passed, the result is undefined. -. -. -.SS "General comments about UTF modes" -.rs -.sp -1. Codepoints less than 256 can be specified in patterns by either braced or -unbraced hexadecimal escape sequences (for example, \ex{b3} or \exb3). Larger -values have to use braced sequences. -.P -2. Octal numbers up to \e777 are recognized, and in UTF-8 mode they match -two-byte characters for values greater than \e177. -.P -3. Repeat quantifiers apply to complete UTF characters, not to individual -data units, for example: \ex{100}{3}. -.P -4. The dot metacharacter matches one UTF character instead of a single data -unit. -.P -5. The escape sequence \eC can be used to match a single byte in UTF-8 mode, or -a single 16-bit data unit in UTF-16 mode, or a single 32-bit data unit in -UTF-32 mode, but its use can lead to some strange effects because it breaks up -multi-unit characters (see the description of \eC in the -.\" HREF -\fBpcrepattern\fP -.\" -documentation). The use of \eC is not supported in the alternative matching -function \fBpcre[16|32]_dfa_exec()\fP, nor is it supported in UTF mode by the -JIT optimization of \fBpcre[16|32]_exec()\fP. If JIT optimization is requested -for a UTF pattern that contains \eC, it will not succeed, and so the matching -will be carried out by the normal interpretive function. -.P -6. The character escapes \eb, \eB, \ed, \eD, \es, \eS, \ew, and \eW correctly -test characters of any code value, but, by default, the characters that PCRE -recognizes as digits, spaces, or word characters remain the same set as in -non-UTF mode, all with values less than 256. This remains true even when PCRE -is built to include Unicode property support, because to do otherwise would -slow down PCRE in many common cases. Note in particular that this applies to -\eb and \eB, because they are defined in terms of \ew and \eW. If you really -want to test for a wider sense of, say, "digit", you can use explicit Unicode -property tests such as \ep{Nd}. Alternatively, if you set the PCRE_UCP option, -the way that the character escapes work is changed so that Unicode properties -are used to determine which characters match. There are more details in the -section on -.\" HTML <a href="pcrepattern.html#genericchartypes"> -.\" </a> -generic character types -.\" -in the -.\" HREF -\fBpcrepattern\fP -.\" -documentation. -.P -7. Similarly, characters that match the POSIX named character classes are all -low-valued characters, unless the PCRE_UCP option is set. -.P -8. However, the horizontal and vertical white space matching escapes (\eh, \eH, -\ev, and \eV) do match all the appropriate Unicode characters, whether or not -PCRE_UCP is set. -.P -9. Case-insensitive matching applies only to characters whose values are less -than 128, unless PCRE is built with Unicode property support. A few Unicode -characters such as Greek sigma have more than two codepoints that are -case-equivalent. Up to and including PCRE release 8.31, only one-to-one case -mappings were supported, but later releases (with Unicode property support) do -treat as case-equivalent all versions of characters such as Greek sigma. -. -. -.SH AUTHOR -.rs -.sp -.nf -Philip Hazel -University Computing Service -Cambridge CB2 3QH, England. -.fi -. -. -.SH REVISION -.rs -.sp -.nf -Last updated: 27 February 2013 -Copyright (c) 1997-2013 University of Cambridge. -.fi |