-.\" Copyright (c) 2001 Andreas S. Oesterhelt <oes@oesterhelt.org>
+.\" Copyright (c) 2001-2003 Andreas S. Oesterhelt <oes@oesterhelt.org>
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, write to the Free
-.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
-.\" USA.
+.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+.\" MA 02111, USA.
.\"
-.TH PCRS 3 "17 August 2001"
+.TH PCRS 3 "2 December 2003" "pcrs-0.0.3"
.SH NAME
pcrs - Perl-compatible regular substitution.
.SH SYNOPSIS
.br
+.B "#include <pcrs.h>"
.PP
.br
-.BI "pcrs_job *pcrs_compile(const char *" "pattern" ","
+.BI "pcrs_job *pcrs_compile(const char *" pattern ","
.ti +5n
-.BI "const char *" "substitute" ", const char *" "options" ","
+.BI "const char *" substitute ", const char *" options ,
.ti +5n
-.BI "int *" "errptr" ");"
+.BI "int *" errptr );
.PP
.br
-.BI "pcrs_job *pcrs_compile_command(const char *" "command" ","
+.BI "pcrs_job *pcrs_compile_command(const char *" command ,
.ti +5n
-.BI "int *" "errptr");
+.BI "int *" errptr );
.PP
.br
-.BI "int pcrs_execute(pcrs_job *" "job" ", char *" "subject" ","
+.BI "int pcrs_execute(pcrs_job *" job ", char *" subject ,
.ti +5n
-.BI "int " "subject_length" ", char **" "result" ","
+.BI "int " subject_length ", char **" result ,
.ti +5n
-.BI "int *" "result_length" ");"
+.BI "int *" result_length );
.PP
.br
-.BI "int pcrs_execute_list (pcrs_job *" "joblist" ", char *" "subject" ","
+.BI "int pcrs_execute_list (pcrs_job *" joblist ", char *" subject ,
.ti +5n
-.BI "int " "subject_length" ", char **" "result" ","
+.BI "int " subject_length ", char **" result ,
.ti +5n
-.BI "int *" "result_length" ");"
+.BI "int *" result_length );
.PP
.br
-.BI "pcrs_job *pcrs_free_job(pcrs_job *" "job" ");"
+.BI "pcrs_job *pcrs_free_job(pcrs_job *" job );
.PP
.br
-.BI "void pcrs_free_joblist(pcrs_job *" "joblist" ");"
+.BI "void pcrs_free_joblist(pcrs_job *" joblist );
.PP
.br
-.BI "char *pcrs_strerror(int " "err" ");"
+.BI "char *pcrs_strerror(int " err );
.PP
.br
.SH DESCRIPTION
+
The
.SM PCRS
-library is a supplement to the
+library is a supplement to the
.SB PCRE(3)
library that implements
-.RB "regular expression based substitution, like provided by " "Perl(1)" "'s 's'"
+.RB "regular expression based substitution, like provided by " Perl(1) "'s 's'"
operator. It uses the same syntax and semantics as Perl 5, with just a few
differences (see below).
In a first step, the information on a substitution, i.e. the pattern, the
substitute and the options are compiled from Perl syntax to an internal form
-.RB "called " "pcrs_job" " by using either the " "pcrs_compile()" " or "
-.BR "pcrs_compile_command()" " functions."
+.RB "called " pcrs_job " by using either the " pcrs_compile() " or "
+.BR pcrs_compile_command() " functions."
-Once the job is compiled, it can be used on subjects, which are arbitrary
+Once the job is compiled, it can be used on subjects, which are arbitrary
memory areas containing string or binary data, by calling
-.BR "pcrs_execute()" ". Jobs can be chained to joblists and whole"
-.RB "joblists can be applied to a subject using " "pcrs_execute_list()" "."
+.BR pcrs_execute() ". Jobs can be chained to joblists and whole"
+.RB "joblists can be applied to a subject using " pcrs_execute_list() .
There are also convenience functions for freeing the jobs and for errno-to-string
-.RB "conversion, namely " "pcrs_free_job()" ", " "pcrs_free_joblist()" " and "
-.BR "pcrs_strerror()" "."
+.RB "conversion, namely " pcrs_free_job() ", " pcrs_free_joblist() " and "
+.BR pcrs_strerror() .
.SH COMPILING JOBS
-.RB "The function " "pcrs_compile()" " is called to compile a " "pcrs_job"
-.RI "from a " "pattern" ", " "substitute" " and " "options" " string.
+
+.RB "The function " pcrs_compile() " is called to compile a " pcrs_job
+.RI "from a " pattern ", " substitute " and " options " string."
.RB "The resulting " "pcrs_job" " structure is dynamically allocated and it"
-.RB "is the caller's responsibility to " "free()" " it when it's no longer needed."
+.RB "is the caller's responsibility to call " "pcrs_free_job()" " when it's no longer needed."
.BR "pcrs_compile_command()" " is a convenience wrapper function that parses a Perl"
.IR "command" " of the form"
.RB "follows the '" "s" "' will be used as the delimiter. Patterns or substitutes"
that contain the delimiter need to quote it:
\fBs/th\\/is/th\\/at/\fR
-.RB "will replace " "th/is" " by " "th/at" " and can be written more simply as"
+.RB "will replace " "th/is" " by " "th/at" " and can be written more simply as"
.BR "s|th/is|th/at|" "."
.IR "pattern" ", " "substitute" ", " "options" " and " "command" " must be"
.SS Substitutes
.RI "The " "substitute" " uses"
.RB "Perl syntax as documented in the " "perlre(1)" " manual page, with"
-some exceptions:
+some exceptions:
Most notably and evidently, since
.SM PCRS
if a global substitution previously matched.
.PP
-Perl4-style references to subpattern matches of the form
+Perl4-style references to subpattern matches of the form
\fB\\1, \\2, ...\fR
-.RB "which only exist in Perl5 for backwards compatibility, are " "not"
+.RB "which only exist in Perl5 for backwards compatibility, are " "not"
supported.
Also, since the substitute is a double-quoted string in Perl, you
.RI "The first " subject_length " bytes following " subject " are processed, so"
.RI "a " subject_length " that exceeds the actual " subject " is dangerous."
-Note that if you want to get your zero-terminated C strings back including their
-.RI "termination, you must let " subject_length " include the binary zero, i.e."
-set it to
-.BI strlen( subject ") + 1."
+.RI "Note that for zero-terminated C strings, you should set " subject_length " to"
+.BI strlen( subject ) \fR,
+so that the dollar metacharacter matches at the end of the string, not after
+the string-terminating null byte. For convenience, an extra null byte is
+appended to the result so it can again be used as a string.
.RI "The " subject " itself is left untouched, and the " *result " is dynamically"
.RB "allocated, so it is the caller's responsibility to " free() " it when it's"
no longer needed.
-.RI "The result's length is written to " *result_length "."
+.RI "The result's length (excluding the extra null byte) is written to " *result_length "."
.RB "If the job matched, the " PCRS_SUCCESS " flag in"
.IB job ->flags
is set.
+
+.SS String subjects
+If your
+
.SS Return value and diagnostics
.RB "On success, " pcrs_execute() " returns the number of substitutions that"
were made, which is limited to 0 or 1 for non-global searches.
-.RI "On failure, a negative error code is returned and " *result " is set"
+.RI "On failure, a negative error code is returned and " result " is set"
.RB "to " NULL .
.SH FREEING JOBS
.RB "It is not sufficient to call " free() " on a " pcrs_job ", because it "
contains pointers to other dynamically allocated structures.
-.RB "Use " pcrs_free() " instead. It is safe to pass " NULL " pointers "
+.RB "Use " pcrs_free_job() " instead. It is safe to pass " NULL " pointers "
.RB "(or pointers to invalid " pcrs_job "s that contain " NULL " pointers"
-.RB "to dependant structures) to " pcrs_free() "."
+.RB "to dependant structures) to " pcrs_free_job() "."
.SS Return value
.RB "The value of the job's " next " pointer."
Chaining the jobs is up to you, but once you have built a linked list of jobs,
.RI "you can execute a whole " joblist " on a given subject by"
.RB "a single call to " pcrs_execute_list() ", which will sequentially traverse"
-.RB "the linked list until it reaches a " NULL " pointer, and call " pcrs_execute()
+.RB "the linked list until it reaches a " NULL " pointer, and call " pcrs_execute()
.RI "for each job it encounters, feeding the " result " and " result_length " of each"
.RI "call into the next as the " subject " and " subject_length ". As in the single"
.RI "job case, the original " subject " remains untouched, but all interim " result "s"
.IR command ", the"
.RB ' $ "' in a"
.IR substitute ", and, of course, itself. Note that the"
-.RB ' $ "'doesn't need to be quoted if it isn't followed by " [0-9+'`&] "."
+.RB ' $ "' doesn't need to be quoted if it isn't followed by " [0-9+'`&] "."
.RI "For quoting in the " pattern ", please refer to"
.BR PCRE(3) .
While compiling the pattern,
.SM PCRE
ran out of memory.
-.TP
+.TP
.B PCRS_ERR_NOMEM
While compiling the job,
.SM PCRS
ran out of memory.
-.TP
+.TP
.B PCRS_ERR_CMDSYNTAX
.BR pcrs_compile_command() " didn't find four tokens while parsing the"
.IR command .
-.TP
+.TP
.B PCRS_ERR_STUDY
A
.SM PCRE
.RB "error occured while studying the compiled pattern. Since " pcre_study()
only provides textual diagnostic information, the details are lost.
-.TP
+.TP
.B PCRS_WARN_BADREF
.RI "The " substitute " contains a reference to a capturing subpattern that"
.RI "has a higher index than the number of capturing subpatterns in the " pattern
ran out of memory. This can only happen if there are more than 33 backrefrences
.RI "in the " pattern "(!)"
.BR and " memory is too tight to extend storage for more."
-.TP
+.TP
.B PCRS_ERR_NOMEM
While executing the job,
.SM PCRS
ran out of memory.
-.TP
+.TP
.B PCRS_ERR_BADJOB
.RB "The " pcrs_job "* passed to " pcrs_execute " was NULL, or the"
.RB "job is bogus (it contains " NULL " pointers to the compiled
{
pcrs_job *job;
char *result;
- int newsize, err;
+ size_t newsize;
+ int err;
if (Argc != 3)
{
if (NULL == (job = pcrs_compile_command(Argv[1], &err)))
{
- printf("Compile error: %s (%d).\\n", pcrs_strerror(err), err);
+ fprintf(stderr, "%s: compile error: %s (%d).\\n", Argv[0], pcrs_strerror(err), err);
}
- if (0 > (err = pcrs_execute(job, Argv[2], strlen(Argv[2]) + 1, &result, &newsize)))
+ if (0 > (err = pcrs_execute(job, Argv[2], strlen(Argv[2]), &result, &newsize)))
{
- printf("Exec error: %s (%d).\\n", pcrs_strerror(err), err);
+ fprintf(stderr, "%s: exec error: %s (%d).\\n", Argv[0], pcrs_strerror(err), err);
+ }
+ else
+ {
+ printf("Result: *%s*\\n", result);
+ free(result);
}
-
- /* Will tolerate NULL result */
- printf("Result: *%s*\\n", result);
pcrs_free_job(job);
- if (result) free(result);
+ return(err < 0);
- return 0;
}
.fi
.SH LIMITATIONS
The number of matches that a global job can have is only limited by the
available memory. An initial storage for 40 matches is reserved, which
-is dynamically resized by the factor 1.6 if exhausted.
+is dynamically resized by the factor 1.6 whenever it is exhausted.
The number of capturing subpatterns is currently limited to 33, which
is a Bad Thing[tm]. It should be dynamically expanded until it reaches the
.SM PCRE
limit of 99.
+.br
+This limitation is particularly embarassing since
+.SM PCRE
+3.5 has raised the capturing subpattern limit to 65K.
All of the above values can be adjusted in the "Capacity" section
.RB "of " pcrs.h "."
.SH HISTORY
.SM PCRS
-was originally written for the Internet Junkbuster project
-(http://sourceforge.net/projects/ijbswa/).
+was originally written for the Privoxy project
+(http://www.privoxy.org/).
.SH SEE ALSO
.B PCRE(3), perl(1), perlre(1)
.SH AUTHOR
.SM PCRS
-is Copyright 2000, 2001 by Andreas Oesterhelt <oes@oesterhelt.org> and is
-licensed under the Terms of the GNU Lesser General Public License (LGPL), which
-should be included in this distribution.
-
-If not, refer to http://www.gnu.org/licenses/lgpl.html or write to the Free
-Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
\ No newline at end of file
+is Copyright 2000 - 2003 by Andreas Oesterhelt <andreas@oesterhelt.org> and is
+licensed under the terms of the GNU Lesser General Public License (LGPL),
+version 2.1, which should be included in this distribution, with the exception
+that the permission to replace that license with the GNU General Public
+License (GPL) given in section 3 is restricted to version 2 of the GPL.
+
+If it is missing from this distribution, the LGPL can be obtained from
+http://www.gnu.org/licenses/lgpl.html or by mail: Write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
projects / privoxy.git / blobdiff