head 1.5; access; symbols FSL_1_7_0:1.5 LMTP2NNTP_1_4_1:1.5 LMTP2NNTP_1_4_0:1.5 FSL_1_6_1:1.5 FSL_1_6_0:1.5 FSL_1_6b2:1.5 FSL_1_6b1:1.5 LMTP2NNTP_1_3_0:1.5 LMTP2NNTP_1_3b2:1.5 LMTP2NNTP_1_3b1:1.5 LMTP2NNTP_1_3a3:1.5 FSL_1_5_0:1.5 LMTP2NNTP_1_3a2:1.5 FSL_1_5a3:1.5 LMTP2NNTP_1_3a1:1.5 FSL_1_5a2:1.5 FSL_1_5a1:1.5 FSL_1_4_0:1.5 FSL_1_4b1:1.5 FSL_1_4a1:1.5 FSL_1_3_0:1.5 FSL_1_3b1:1.5 FSL_1_2_1:1.5 FSL_1_2_0:1.5 FSL_1_1_0:1.5 FSL_1_1b1:1.5 FSL_1_0_8:1.5 LMTP2NNTP_1_2_0:1.5 LMTP2NNTP_1_2b4:1.5 LMTP2NNTP_1_2b3:1.5 LMTP2NNTP_1_2b2:1.5 LMTP2NNTP_1_2b1:1.5 LMTP2NNTP_1_2a8:1.5 LMTP2NNTP_1_2a7:1.5 FSL_1_0_7:1.5 FSL_1_0_6:1.5 FSL_1_0_5:1.5 FSL_1_0_4:1.5 FSL_1_0_3:1.5 LMTP2NNTP_1_2a6:1.5 FSL_1_0_2:1.5 FSL_1_0_1:1.5 FSL_1_0_0:1.5 FSL_0_9_0:1.5 FSL_0_1_12:1.5 FSL_0_1_11:1.5 FSL_0_1_10:1.5 FSL_0_1_9:1.5 FSL_0_1_8:1.5 FSL_0_1_7:1.5 FSL_0_1_6:1.5 FSL_0_1_5:1.5 FSL_0_1_1:1.5 LMTP2NNTP_1_2a5:1.5 LMTP2NNTP_1_2a4:1.5 LMTP2NNTP_1_2a3:1.5 OSSP_PCRE_2_07:1.1.1.1 ossp:1.1.1; locks; strict; comment @# @; 1.5 date 2002.01.07.14.36.54; author rse; state Exp; branches; next 1.4; 1.4 date 2000.08.02.09.46.06; author rse; state Exp; branches; next 1.3; 1.3 date 2000.02.02.17.18.46; author rse; state Exp; branches; next 1.2; 1.2 date 99.09.28.10.33.05; author rse; state Exp; branches; next 1.1; 1.1 date 99.08.26.08.15.19; author rse; state Exp; branches 1.1.1.1; next ; 1.1.1.1 date 99.08.26.08.15.19; author rse; state Exp; branches; next ; desc @@ 1.5 log @merge changes from 3.4 to 3.5 @ text @README file for PCRE (Perl-compatible regular expression library) ----------------------------------------------------------------- The latest release of PCRE is always available from ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz Please read the NEWS file if you are upgrading from a previous release. PCRE has its own native API, but a set of "wrapper" functions that are based on the POSIX API are also supplied in the library libpcreposix. Note that this just provides a POSIX calling interface to PCRE: the regular expressions themselves still follow Perl syntax and semantics. The header file for the POSIX-style functions is called pcreposix.h. The official POSIX name is regex.h, but I didn't want to risk possible problems with existing files of that name by distributing it that way. To use it with an existing program that uses the POSIX API, it will have to be renamed or pointed at by a link. Contributions by users of PCRE ------------------------------ You can find contributions from PCRE users in the directory ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib where there is also a README file giving brief descriptions of what they are. Several of them provide support for compiling PCRE on various flavours of Windows systems (I myself do not use Windows). Some are complete in themselves; others are pointers to URLs containing relevant files. Building PCRE on a Unix system ------------------------------ To build PCRE on a Unix system, first run the "configure" command from the PCRE distribution directory, with your current directory set to the directory where you want the files to be created. This command is a standard GNU "autoconf" configuration script, for which generic instructions are supplied in INSTALL. Most commonly, people build PCRE within its own distribution directory, and in this case, on many systems, just running "./configure" is sufficient, but the usual methods of changing standard defaults are available. For example, CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local specifies that the C compiler should be run with the flags '-O2 -Wall' instead of the default, and that "make install" should install PCRE under /opt/local instead of the default /usr/local. If you want to build in a different directory, just run "configure" with that directory as current. For example, suppose you have unpacked the PCRE source into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx: cd /build/pcre/pcre-xxx /source/pcre/pcre-xxx/configure If you want to make use of the experimential, incomplete support for UTF-8 character strings in PCRE, you must add --enable-utf8 to the "configure" command. Without it, the code for handling UTF-8 is not included in the library. (Even when included, it still has to be enabled by an option at run time.) The "configure" script builds five files: . libtool is a script that builds shared and/or static libraries . Makefile is built by copying Makefile.in and making substitutions. . config.h is built by copying config.in and making substitutions. . pcre-config is built by copying pcre-config.in and making substitutions. . RunTest is a script for running tests Once "configure" has run, you can run "make". It builds two libraries called libpcre and libpcreposix, a test program called pcretest, and the pcregrep command. You can use "make install" to copy these, the public header files pcre.h and pcreposix.h, and the man pages to appropriate live directories on your system, in the normal way. Running "make install" also installs the command pcre-config, which can be used to recall information about the PCRE configuration and installation. For example, pcre-config --version prints the version number, and pcre-config --libs outputs information about where the library is installed. This command can be included in makefiles for programs that use PCRE, saving the programmer from having to remember too many details. There is one esoteric feature that is controlled by "configure". It concerns the character value used for "newline", and is something that you probably do not want to change on a Unix system. The default is to use whatever value your compiler gives to '\n'. By using --enable-newline-is-cr or --enable-newline-is-lf you can force the value to be CR (13) or LF (10) if you really want to. Shared libraries on Unix systems -------------------------------- The default distribution builds PCRE as two shared libraries and two static libraries, as long as the operating system supports shared libraries. Shared library support relies on the "libtool" script which is built as part of the "configure" process. The libtool script is used to compile and link both shared and static libraries. They are placed in a subdirectory called .libs when they are newly built. The programs pcretest and pcregrep are built to use these uninstalled libraries (by means of wrapper scripts in the case of shared libraries). When you use "make install" to install shared libraries, pcregrep and pcretest are automatically re-built to use the newly installed shared libraries before being installed themselves. However, the versions left in the source directory still use the uninstalled libraries. To build PCRE using static libraries only you must use --disable-shared when configuring it. For example ./configure --prefix=/usr/gnu --disable-shared Then run "make" in the usual way. Similarly, you can use --disable-static to build only shared libraries. Building on non-Unix systems ---------------------------- For a non-Unix system, read the comments in the file NON-UNIX-USE. PCRE has been compiled on Windows systems and on Macintoshes, but I don't know the details because I don't use those systems. It should be straightforward to build PCRE on any system that has a Standard C compiler, because it uses only Standard C functions. Testing PCRE ------------ To test PCRE on a Unix system, run the RunTest script that is created by the configuring process. (This can also be run by "make runtest", "make check", or "make test".) For other systems, see the instruction in NON-UNIX-USE. The script runs the pcretest test program (which is documented in the doc directory) on each of the testinput files (in the testdata directory) in turn, and compares the output with the contents of the corresponding testoutput file. A file called testtry is used to hold the output from pcretest. To run pcretest on just one of the test files, give its number as an argument to RunTest, for example: RunTest 3 The first and third test files can also be fed directly into the perltest script to check that Perl gives the same results. The third file requires the additional features of release 5.005, which is why it is kept separate from the main test input, which needs only Perl 5.004. In the long run, when 5.005 (or higher) is widespread, these two test files may get amalgamated. The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(), pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error detection, and run-time flags that are specific to PCRE, as well as the POSIX wrapper API. It also uses the debugging flag to check some of the internals of pcre_compile(). If you build PCRE with a locale setting that is not the standard C locale, the character tables may be different (see next paragraph). In some cases, this may cause failures in the second set of tests. For example, in a locale where the isprint() function yields TRUE for characters in the range 128-255, the use of [:isascii:] inside a character class defines a different set of characters, and this shows up in this test as a difference in the compiled code, which is being listed for checking. Where the comparison test output contains [\x00-\x7f] the test will contain [\x00-\xff], and similarly in some other cases. This is not a bug in PCRE. The fourth set of tests checks pcre_maketables(), the facility for building a set of character tables for a specific locale and using them instead of the default tables. The tests make use of the "fr" (French) locale. Before running the test, the script checks for the presence of this locale by running the "locale" command. If that command fails, or if it doesn't include "fr" in the list of available locales, the fourth test cannot be run, and a comment is output to say why. If running this test produces instances of the error ** Failed to set locale "fr" in the comparison output, it means that locale is not available on your system, despite being listed by "locale". This does not mean that PCRE is broken. The fifth test checks the experimental, incomplete UTF-8 support. It is not run automatically unless PCRE is built with UTF-8 support. This file can be fed directly to the perltest8 script, which requires Perl 5.6 or higher. The sixth file tests internal UTF-8 features of PCRE that are not relevant to Perl. Character tables ---------------- PCRE uses four tables for manipulating and identifying characters. The final argument of the pcre_compile() function is a pointer to a block of memory containing the concatenated tables. A call to pcre_maketables() can be used to generate a set of tables in the current locale. If the final argument for pcre_compile() is passed as NULL, a set of default tables that is built into the binary is used. The source file called chartables.c contains the default set of tables. This is not supplied in the distribution, but is built by the program dftables (compiled from dftables.c), which uses the ANSI C character handling functions such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table sources. This means that the default C locale which is set for your system will control the contents of these default tables. You can change the default tables by editing chartables.c and then re-building PCRE. If you do this, you should probably also edit Makefile to ensure that the file doesn't ever get re-generated. The first two 256-byte tables provide lower casing and case flipping functions, respectively. The next table consists of three 32-byte bit maps which identify digits, "word" characters, and white space, respectively. These are used when building 32-byte bit maps that represent character classes. The final 256-byte table has bits indicating various character types, as follows: 1 white space character 2 letter 4 decimal digit 8 hexadecimal digit 16 alphanumeric or '_' 128 regular expression metacharacter or binary zero You should not alter the set of characters that contain the 128 bit, as that will cause PCRE to malfunction. Manifest -------- The distribution should contain the following files: (A) The actual source files of the PCRE library functions and their headers: dftables.c auxiliary program for building chartables.c get.c ) maketables.c ) study.c ) source of pcre.c ) the functions pcreposix.c ) pcre.in "source" for the header for the external API; pcre.h is built from this by "configure" pcreposix.h header for the external POSIX wrapper API internal.h header for internal use config.in template for config.h, which is built by configure (B) Auxiliary files: AUTHORS information about the author of PCRE ChangeLog log of changes to the code INSTALL generic installation instructions LICENCE conditions for the use of PCRE COPYING the same, using GNU's standard name Makefile.in template for Unix Makefile, which is built by configure NEWS important changes in this release NON-UNIX-USE notes on building PCRE on non-Unix systems README this file RunTest.in template for a Unix shell script for running tests config.guess ) files used by libtool, config.sub ) used only when building a shared library configure a configuring shell script (built by autoconf) configure.in the autoconf input used to build configure doc/Tech.Notes notes on the encoding doc/pcre.3 man page source for the PCRE functions doc/pcre.html HTML version doc/pcre.txt plain text version doc/pcreposix.3 man page source for the POSIX wrapper API doc/pcreposix.html HTML version doc/pcreposix.txt plain text version doc/pcretest.txt documentation of test program doc/perltest.txt documentation of Perl test program doc/pcregrep.1 man page source for the pcregrep utility doc/pcregrep.html HTML version doc/pcregrep.txt plain text version install-sh a shell script for installing files ltmain.sh file used to build a libtool script pcretest.c comprehensive test program pcredemo.c simple demonstration of coding calls to PCRE perltest Perl test program perltest8 Perl test program for UTF-8 tests pcregrep.c source of a grep utility that uses PCRE pcre-config.in source of script which retains PCRE information testdata/testinput1 test data, compatible with Perl 5.004 and 5.005 testdata/testinput2 test data for error messages and non-Perl things testdata/testinput3 test data, compatible with Perl 5.005 testdata/testinput4 test data for locale-specific tests testdata/testinput5 test data for UTF-8 tests compatible with Perl 5.6 testdata/testinput6 test data for other UTF-8 tests testdata/testoutput1 test results corresponding to testinput1 testdata/testoutput2 test results corresponding to testinput2 testdata/testoutput3 test results corresponding to testinput3 testdata/testoutput4 test results corresponding to testinput4 testdata/testoutput5 test results corresponding to testinput5 testdata/testoutput6 test results corresponding to testinput6 (C) Auxiliary files for Win32 DLL dll.mk pcre.def Philip Hazel August 2001 @ 1.4 log @Upgrade to PCRE 3.3 and GNU shtool 1.5.1 @ text @d20 13 d36 8 a43 5 To build PCRE on a Unix system, run the "configure" command in the PCRE distribution directory. This is a standard GNU "autoconf" configuration script, for which generic instructions are supplied in INSTALL. On many systems just running "./configure" is sufficient, but the usual methods of changing standard defaults are available. For example, d51 7 d64 1 a64 1 The "configure" script builds four files: d66 1 d74 3 a76 2 command. You can use "make install" to copy these, and the public header file pcre.h, to appropriate live directories on your system, in the normal way. d92 7 d103 13 a115 9 The default distribution builds PCRE as two shared libraries. This support is new and experimental and may not work on all systems. It relies on the "libtool" scripts - these are distributed with PCRE. It should build a "libtool" script and use this to compile and link shared libraries, which are placed in a subdirectory called .libs. The programs pcretest and pcregrep are built to use these uninstalled libraries by means of wrapper scripts. When you use "make install" to install shared libraries, pcregrep and pcretest are automatically re-built to use the newly installed libraries. However, only pcregrep is installed, as pcretest is really just a test program. d117 1 a117 1 To build PCRE using static libraries you must use --disable-shared when d122 2 a123 1 Then run "make" in the usual way. d139 10 a148 10 To test PCRE on a Unix system, run the RunTest script in the pcre directory. (This can also be run by "make runtest", "make check", or "make test".) For other systems, see the instruction in NON-UNIX-USE. The script runs the pcretest test program (which is documented in doc/pcretest.txt) on each of the testinput files (in the testdata directory) in turn, and compares the output with the contents of the corresponding testoutput file. A file called testtry is used to hold the output from pcretest. To run pcretest on just one of the test files, give its number as an argument to RunTest, for example: d281 3 a283 3 ltconfig ) files used to build "libtool", ltmain.sh ) used only when building a shared library pcretest.c test program d307 1 a307 1 August 2000 @ 1.3 log @Update from 2.08 to 3.0 @ text @d10 9 d27 1 a27 1 defaults are available. For example d33 9 a41 1 instead of the default /usr/local. The "configure" script builds thre files: d46 1 d49 1 a49 1 libpcre and libpcreposix, a test program called pcretest, and the pgrep d75 1 a75 1 placed in a subdirectory called .libs. The programs pcretest and pgrep are d77 1 a77 1 use "make install" to install shared libraries, pgrep and pcretest are d79 1 a79 1 pgrep is installed, as pcretest is really just a test program. d103 2 a104 2 (This can also be run by "make runtest" or "make check".) For other systems, see the instruction in NON-UNIX-USE. d118 2 a119 2 main test input, which needs only Perl 5.004. In the long run, when 5.005 is widespread, these two test files may get amalgamated. d121 15 a135 3 The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error detection and run-time flags that are specific to PCRE, as well as the POSIX wrapper API. d150 4 a153 8 PCRE has its own native API, but a set of "wrapper" functions that are based on the POSIX API are also supplied in the library libpcreposix.a. Note that this just provides a POSIX calling interface to PCRE: the regular expressions themselves still follow Perl syntax and semantics. The header file for the POSIX-style functions is called pcreposix.h. The official POSIX name is regex.h, but I didn't want to risk possible problems with existing files of that name by distributing it that way. To use it with an existing program that uses the POSIX API, it will have to be renamed or pointed at by a link. d226 1 a226 1 RunTest a Unix shell script for running tests d240 3 a242 3 doc/pgrep.1 man page source for the pgrep utility doc/pgrep.html HTML version doc/pgrep.txt plain text version d248 2 a249 1 pgrep.c source of a grep utility that uses PCRE d255 2 d261 2 d270 1 a270 1 February 2000 @ 1.2 log @*** empty log message *** @ text @d1 2 a2 2 README file for PCRE (Perl-compatible regular expressions) ---------------------------------------------------------- d4 1 a4 30 ******************************************************************************* * IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00 * * * * Please note that there has been a change in the API such that a larger * * ovector is required at matching time, to provide some additional workspace. * * The new man page has details. This change was necessary in order to support * * some of the new functionality in Perl 5.005. * * * * IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00 * * * * Another (I hope this is the last!) change has been made to the API for the * * pcre_compile() function. An additional argument has been added to make it * * possible to pass over a pointer to character tables built in the current * * locale by pcre_maketables(). To use the default tables, this new arguement * * should be passed as NULL. * * * * IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05 * * * * Yet another (and again I hope this really is the last) change has been made * * to the API for the pcre_exec() function. An additional argument has been * * added to make it possible to start the match other than at the start of the * * subject string. This is important if there are lookbehinds. The new man * * page has the details, but you just want to convert existing programs, all * * you need to do is to stick in a new fifth argument to pcre_exec(), with a * * value of zero. For example, change * * * * pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize) * * to * * pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize) * ******************************************************************************* d6 1 d8 21 a28 1 The distribution should contain the following files: d30 2 a31 42 ChangeLog log of changes to the code LICENCE conditions for the use of PCRE Makefile for building PCRE in Unix systems README this file RunTest a Unix shell script for running tests Tech.Notes notes on the encoding pcre.3 man page source for the functions pcre.3.txt plain text version pcre.3.html HTML version pcreposix.3 man page source for the POSIX wrapper API pcreposix.3.txt plain text version pcreposix.3.HTML HTML version dftables.c auxiliary program for building chartables.c get.c ) maketables.c ) study.c ) source of pcre.c ) the functions pcreposix.c ) pcre.h header for the external API pcreposix.h header for the external POSIX wrapper API internal.h header for internal use pcretest.c test program pgrep.1 man page source for pgrep pgrep.1.txt plain text version pgrep.1.HTML HTML version pgrep.c source of a grep utility that uses PCRE perltest Perl test program testinput1 test data, compatible with Perl 5.004 and 5.005 testinput2 test data for error messages and non-Perl things testinput3 test data, compatible with Perl 5.005 testinput4 test data for locale-specific tests testoutput1 test results corresponding to testinput1 testoutput2 test results corresponding to testinput2 testoutput3 test results corresponding to testinput3 testoutput4 test results corresponding to testinput4 dll.mk for Win32 DLL pcre.def ditto To build PCRE on a Unix system, first edit Makefile for your system. It is a fairly simple make file, and there are some comments near the top, after the text "On a Unix system". Then run "make". It builds two libraries called libpcre.a and libpcreposix.a, a test program called pcretest, and the pgrep d33 61 a93 26 pcre.h, to appropriate live directories on your system. These installation directories are defined at the top of the Makefile, and you should edit them if necessary. For a non-Unix system, read the comments at the top of Makefile, which give some hints on what needs to be done. PCRE has been compiled on Windows systems and on Macintoshes, but I don't know the details as I don't use those systems. It should be straightforward to build PCRE on any system that has a Standard C compiler. Some help in building a Win32 DLL of PCRE in GnuWin32 environments was contributed by Paul.Sokolovsky@@technologist.com. These environments are Mingw32 (http://www.xraylith.wisc.edu/~khan/software/gnu-win32/) and CygWin (http://sourceware.cygnus.com/cygwin/). Paul comments: For CygWin, set CFLAGS=-mno-cygwin, and do 'make dll'. You'll get pcre.dll (containing pcreposix also), libpcre.dll.a, and dynamically linked pgrep and pcretest. If you have /bin/sh, run RunTest (three main test go ok, locale not supported). To test PCRE, run the RunTest script in the pcre directory. This can also be run by "make runtest". It runs the pcretest test program (which is documented below) on each of the testinput files in turn, and compares the output with the contents of the corresponding testoutput file. A file called testtry is used to hold the output from pcretest. To run pcretest on just one of the test files, give its number as an argument to RunTest, for example: d169 2 a170 2 The pcretest program -------------------- d172 4 a175 2 This program is intended for testing PCRE, but it can also be used for experimenting with regular expressions. d177 55 a231 24 If it is given two filename arguments, it reads from the first and writes to the second. If it is given only one filename argument, it reads from that file and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and prompts for each line of input. The program handles any number of sets of input on a single input file. Each set starts with a regular expression, and continues with any number of data lines to be matched against the pattern. An empty line signals the end of the set. The regular expressions are given enclosed in any non-alphameric delimiters other than backslash, for example /(a|bc)x+yz/ White space before the initial delimiter is ignored. A regular expression may be continued over several input lines, in which case the newline characters are included within it. See the testinput files for many examples. It is possible to include the delimiter within the pattern by escaping it, for example /abc\/def/ If you do so, the escape and the delimiter form part of the pattern, but since delimiters are always non-alphameric, this does not affect its interpretation. If the terminating delimiter is immediately followed by a backslash, for example, d233 1 a233 1 /abc/\ d235 2 a236 199 then a backslash is added to the end of the pattern. This is done to provide a way of testing the error condition that arises if a pattern finishes with a backslash, because /abc\/ is interpreted as the first line of a pattern that starts with "abc/", causing pcretest to read the next line as a continuation of the regular expression. The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. For example: /caseless/i These modifier letters have the same effect as they do in Perl. There are others which set PCRE options that do not correspond to anything in Perl: /A, /E, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively. Searching for all possible matches within each subject string can be requested by the /g or /G modifier. After finding a match, PCRE is called again to search the remainder of the subject string. The difference between /g and /G is that the former uses the startoffset argument to pcre_exec() to start searching at a new point within the entire string (which is in effect what Perl does), whereas the latter passes over a shortened substring. This makes a difference to the matching process if the pattern begins with a lookbehind assertion (including \b or \B). If any call to pcre_exec() in a /g or /G sequence matches an empty string, the next call is done with the PCRE_NOTEMPTY flag set so that it cannot match an empty string again. This imitates the way Perl handles such cases when using the /g modifier or the split() function. There are a number of other modifiers for controlling the way pcretest operates. The /+ modifier requests that as well as outputting the substring that matched the entire pattern, pcretest should in addition output the remainder of the subject string. This is useful for tests where the subject contains multiple copies of the same substring. The /L modifier must be followed directly by the name of a locale, for example, /pattern/Lfr For this reason, it must be the last modifier letter. The given locale is set, pcre_maketables() is called to build a set of character tables for the locale, and this is then passed to pcre_compile() when compiling the regular expression. Without an /L modifier, NULL is passed as the tables pointer; that is, /L applies only to the expression on which it appears. The /I modifier requests that pcretest output information about the compiled expression (whether it is anchored, has a fixed first character, and so on). It does this by calling pcre_info() after compiling an expression, and outputting the information it gets back. If the pattern is studied, the results of that are also output. The /D modifier is a PCRE debugging feature, which also assumes /I. It causes the internal form of compiled regular expressions to be output after compilation. The /S modifier causes pcre_study() to be called after the expression has been compiled, and the results used when the expression is matched. The /M modifier causes the size of memory block used to hold the compiled pattern to be output. Finally, the /P modifier causes pcretest to call PCRE via the POSIX wrapper API rather than its native API. When this is done, all other modifiers except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is set if /m is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set. Before each data line is passed to pcre_exec(), leading and trailing whitespace is removed, and it is then scanned for \ escapes. The following are recognized: \a alarm (= BEL) \b backspace \e escape \f formfeed \n newline \r carriage return \t tab \v vertical tab \nnn octal character (up to 3 octal digits) \xhh hexadecimal character (up to 2 hex digits) \A pass the PCRE_ANCHORED option to pcre_exec() \B pass the PCRE_NOTBOL option to pcre_exec() \Cdd call pcre_copy_substring() for substring dd after a successful match (any decimal number less than 32) \Gdd call pcre_get_substring() for substring dd after a successful match (any decimal number less than 32) \L call pcre_get_substringlist() after a successful match \N pass the PCRE_NOTEMPTY option to pcre_exec() \Odd set the size of the output vector passed to pcre_exec() to dd (any number of decimal digits) \Z pass the PCRE_NOTEOL option to pcre_exec() A backslash followed by anything else just escapes the anything else. If the very last character is a backslash, it is ignored. This gives a way of passing an empty line as data, since a real empty line terminates the data input. If /P was present on the regex, causing the POSIX wrapper API to be used, only \B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to regexec() respectively. When a match succeeds, pcretest outputs the list of captured substrings that pcre_exec() returns, starting with number 0 for the string that matched the whole pattern. Here is an example of an interactive pcretest run. $ pcretest PCRE version 2.06 08-Jun-1999 re> /^abc(\d+)/ data> abc123 0: abc123 1: 123 data> xyz No match If the strings contain any non-printing characters, they are output as \0x escapes. If the pattern has the /+ modifier, then the output for substring 0 is followed by the the rest of the subject string, identified by "0+" like this: re> /cat/+ data> cataract 0: cat 0+ aract If the pattern has the /g or /G modifier, the results of successive matching attempts are output in sequence, like this: re> /\Bi(\w\w)/g data> Mississippi 0: iss 1: ss 0: iss 1: ss 0: ipp 1: pp "No match" is output only if the first match attempt fails. If any of \C, \G, or \L are present in a data line that is successfully matched, the substrings extracted by the convenience functions are output with C, G, or L after the string number instead of a colon. This is in addition to the normal full list. The string length (that is, the return from the extraction function) is given in parentheses after each string for \C and \G. Note that while patterns can be continued over several lines (a plain ">" prompt is used for continuations), data lines may not. However newlines can be included in data by means of the \n escape. If the -p option is given to pcretest, it is equivalent to adding /P to each regular expression: the POSIX wrapper API is used to call PCRE. None of the following flags has any effect in this case. If the option -d is given to pcretest, it is equivalent to adding /D to each regular expression: the internal form is output after compilation. If the option -i is given to pcretest, it is equivalent to adding /I to each regular expression: information about the compiled pattern is given after compilation. If the option -m is given to pcretest, it outputs the size of each compiled pattern after it has been compiled. It is equivalent to adding /M to each regular expression. For compatibility with earlier versions of pcretest, -s is a synonym for -m. If the -t option is given, each compile, study, and match is run 20000 times while being timed, and the resulting time per compile or match is output in milliseconds. Do not set -t with -s, because you will then get the size output 20000 times and the timing will be distorted. If you want to change the number of repetitions used for timing, edit the definition of LOOPREPEAT at the top of pcretest.c The perltest program -------------------- The perltest program tests Perl's regular expressions; it has the same specification as pcretest, and so can be given identical input, except that input patterns can be followed only by Perl's lower case modifiers. The contents of testinput1 and testinput3 meet this condition. The data lines are processed as Perl double-quoted strings, so if they contain " \ $ or @@ characters, these have to be escaped. For this reason, all such characters in testinput1 and testinput3 are escaped so that they can be used for perltest as well as for pcretest, and the special upper case modifiers such as /A that pcretest recognizes are not used in these files. The output should be identical, apart from the initial identifying banner. The testinput2 and testinput4 files are not suitable for feeding to perltest, since they do make use of the special upper case modifiers and escapes that pcretest uses to test some features of PCRE. The first of these files also contains malformed regular expressions, in order to check that PCRE diagnoses them correctly. d239 1 a239 242 June 1999 Technical Notes about PCRE -------------------------- Many years ago I implemented some regular expression functions to an algorithm suggested by Martin Richards. These were not Unix-like in form, and were quite restricted in what they could do by comparison with Perl. The interesting part about the algorithm was that the amount of space required to hold the compiled form of an expression was known in advance. The code to apply an expression did not operate by backtracking, as the Henry Spencer and Perl code does, but instead checked all possibilities simultaneously by keeping a list of current states and checking all of them as it advanced through the subject string. (In the terminology of Jeffrey Friedl's book, it was a "DFA algorithm".) When the pattern was all used up, all remaining states were possible matches, and the one matching the longest subset of the subject string was chosen. This did not necessarily maximize the individual wild portions of the pattern, as is expected in Unix and Perl-style regular expressions. By contrast, the code originally written by Henry Spencer and subsequently heavily modified for Perl actually compiles the expression twice: once in a dummy mode in order to find out how much store will be needed, and then for real. The execution function operates by backtracking and maximizing (or, optionally, minimizing in Perl) the amount of the subject that matches individual wild portions of the pattern. This is an "NFA algorithm" in Friedl's terminology. For this set of functions that forms PCRE, I tried at first to invent an algorithm that used an amount of store bounded by a multiple of the number of characters in the pattern, to save on compiling time. However, because of the greater complexity in Perl regular expressions, I couldn't do this. In any case, a first pass through the pattern is needed, in order to find internal flag settings like (?i) at top level. So it works by running a very degenerate first pass to calculate a maximum store size, and then a second pass to do the real compile - which may use a bit less than the predicted amount of store. The idea is that this is going to turn out faster because the first pass is degenerate and the second can just store stuff straight into the vector. It does make the compiling functions bigger, of course, but they have got quite big anyway to handle all the Perl stuff. The compiled form of a pattern is a vector of bytes, containing items of variable length. The first byte in an item is an opcode, and the length of the item is either implicit in the opcode or contained in the data bytes which follow it. A list of all the opcodes follows: Opcodes with no following data ------------------------------ These items are all just one byte long OP_END end of pattern OP_ANY match any character OP_SOD match start of data: \A OP_CIRC ^ (start of data, or after \n in multiline) OP_NOT_WORD_BOUNDARY \W OP_WORD_BOUNDARY \w OP_NOT_DIGIT \D OP_DIGIT \d OP_NOT_WHITESPACE \S OP_WHITESPACE \s OP_NOT_WORDCHAR \W OP_WORDCHAR \w OP_EODN match end of data or \n at end: \Z OP_EOD match end of data: \z OP_DOLL $ (end of data, or before \n in multiline) Repeating single characters --------------------------- The common repeats (*, +, ?) when applied to a single character appear as two-byte items using the following opcodes: OP_STAR OP_MINSTAR OP_PLUS OP_MINPLUS OP_QUERY OP_MINQUERY Those with "MIN" in their name are the minimizing versions. Each is followed by the character that is to be repeated. Other repeats make use of OP_UPTO OP_MINUPTO OP_EXACT which are followed by a two-byte count (most significant first) and the repeated character. OP_UPTO matches from 0 to the given number. A repeat with a non-zero minimum and a fixed maximum is coded as an OP_EXACT followed by an OP_UPTO (or OP_MINUPTO). Repeating character types ------------------------- Repeats of things like \d are done exactly as for single characters, except that instead of a character, the opcode for the type is stored in the data byte. The opcodes are: OP_TYPESTAR OP_TYPEMINSTAR OP_TYPEPLUS OP_TYPEMINPLUS OP_TYPEQUERY OP_TYPEMINQUERY OP_TYPEUPTO OP_TYPEMINUPTO OP_TYPEEXACT Matching a character string --------------------------- The OP_CHARS opcode is followed by a one-byte count and then that number of characters. If there are more than 255 characters in sequence, successive instances of OP_CHARS are used. Character classes ----------------- OP_CLASS is used for a character class, provided there are at least two characters in the class. If there is only one character, OP_CHARS is used for a positive class, and OP_NOT for a negative one (that is, for something like [^a]). Another set of repeating opcodes (OP_NOTSTAR etc.) are used for a repeated, negated, single-character class. The normal ones (OP_STAR etc.) are used for a repeated positive single-character class. OP_CLASS is followed by a 32-byte bit map containing a 1 bit for every character that is acceptable. The bits are counted from the least significant end of each byte. Back references --------------- OP_REF is followed by a single byte containing the reference number. Repeating character classes and back references ----------------------------------------------- Single-character classes are handled specially (see above). This applies to OP_CLASS and OP_REF. In both cases, the repeat information follows the base item. The matching code looks at the following opcode to see if it is one of OP_CRSTAR OP_CRMINSTAR OP_CRPLUS OP_CRMINPLUS OP_CRQUERY OP_CRMINQUERY OP_CRRANGE OP_CRMINRANGE All but the last two are just single-byte items. The others are followed by four bytes of data, comprising the minimum and maximum repeat counts. Brackets and alternation ------------------------ A pair of non-identifying (round) brackets is wrapped round each expression at compile time, so alternation always happens in the context of brackets. Non-identifying brackets use the opcode OP_BRA, while identifying brackets use OP_BRA+1, OP_BRA+2, etc. [Note for North Americans: "bracket" to some English speakers, including myself, can be round, square, or curly. Hence this usage.] A bracket opcode is followed by two bytes which give the offset to the next alternative OP_ALT or, if there aren't any branches, to the matching KET opcode. Each OP_ALT is followed by two bytes giving the offset to the next one, or to the KET opcode. OP_KET is used for subpatterns that do not repeat indefinitely, while OP_KETRMIN and OP_KETRMAX are used for indefinite repetitions, minimally or maximally respectively. All three are followed by two bytes giving (as a positive number) the offset back to the matching BRA opcode. If a subpattern is quantified such that it is permitted to match zero times, it is preceded by one of OP_BRAZERO or OP_BRAMINZERO. These are single-byte opcodes which tell the matcher that skipping this subpattern entirely is a valid branch. A subpattern with an indefinite maximum repetition is replicated in the compiled data its minimum number of times (or once with a BRAZERO if the minimum is zero), with the final copy terminating with a KETRMIN or KETRMAX as appropriate. A subpattern with a bounded maximum repetition is replicated in a nested fashion up to the maximum number of times, with BRAZERO or BRAMINZERO before each replication after the minimum, so that, for example, (abc){2,5} is compiled as (abc)(abc)((abc)((abc)(abc)?)?)?. The 200-bracket limit does not apply to these internally generated brackets. Assertions ---------- Forward assertions are just like other subpatterns, but starting with one of the opcodes OP_ASSERT or OP_ASSERT_NOT. Backward assertions use the opcodes OP_ASSERTBACK and OP_ASSERTBACK_NOT, and the first opcode inside the assertion is OP_REVERSE, followed by a two byte count of the number of characters to move back the pointer in the subject string. A separate count is present in each alternative of a lookbehind assertion, allowing them to have different fixed lengths. Once-only subpatterns --------------------- These are also just like other subpatterns, but they start with the opcode OP_ONCE. Conditional subpatterns ----------------------- These are like other subpatterns, but they start with the opcode OP_COND. If the condition is a back reference, this is stored at the start of the subpattern using the opcode OP_CREF followed by one byte containing the reference number. Otherwise, a conditional subpattern will always start with one of the assertions. Changing options ---------------- If any of the /i, /m, or /s options are changed within a parenthesized group, an OP_OPT opcode is compiled, followed by one byte containing the new settings of these flags. If there are several alternatives in a group, there is an occurrence of OP_OPT at the start of all those following the first options change, to set appropriate options for the start of the alternative. Immediately after the end of the group there is another such item to reset the flags to their previous values. Other changes of flag within the pattern can be handled entirely at compile time, and so do not cause anything to be put into the compiled data. Philip Hazel January 1999 @ 1.1 log @Initial revision @ text @d73 2 d91 10 d235 12 a246 7 by the /g or /G modifier. The /g modifier behaves similarly to the way it does in Perl. After finding a match, PCRE is called again to search the remainder of the subject string. The difference between /g and /G is that the former uses the start_offset argument to pcre_exec() to start searching at a new point within the entire string, whereas the latter passes over a shortened substring. This makes a difference to the matching process if the pattern begins with a lookbehind assertion (including \b or \B). @ 1.1.1.1 log @Import OSSP pcre @ text @@