#include <pcre++.h>
Public Methods | |
Pcre () | |
Pcre (const string &expression) | |
Pcre (const string &expression, const string &flags) | |
Pcre (const Pcre &P) | |
const Pcre & | operator= (const string &expression) |
const Pcre & | operator= (const Pcre &P) |
~Pcre () | |
bool | search (const string &stuff) |
bool | search (const string &stuff, int OffSet) |
Array * | get_sub_strings () |
string | get_match (int pos) |
int | get_match_start (int pos) |
int | get_match_end (int pos) |
size_t | get_match_length (int pos) |
bool | matched () |
int | matches () |
Array | split (const string &piece) |
Array | split (const string &piece, int limit) |
Array | split (const string &piece, int limit, int start_offset) |
Array | split (const string &piece, int limit, int start_offset, int end_offset) |
Array | split (const string &piece, vector< int > positions) |
string | replace (const string &piece, const string &with) |
Public Attributes | |
bool | did_match |
int | num_matches |
The library "pcre++" defines a class named "Pcre" which you can use to search in strings using reular expressions as well as getting matched sub strings. It does currently not support all features, which the underlying PCRE library provides, but the most important stuff is implemented.
Please study this example code to learn how to use this class:
/* * * This file is part of the PCRE++ Class Library. * * By accessing this software, PCRE++, you are duly informed * of and agree to be bound by the conditions described below * in this notice: * * This software product, PCRE++, is developed by Thomas Linden * and copyrighted (C) 2002 by Thomas Linden, with all rights * reserved. * * There is no charge for PCRE++ software. You can redistribute * it and/or modify it under the terms of the GNU Lesser General * Public License, which is incorporated by reference herein. * * PCRE++ is distributed WITHOUT ANY WARRANTY, IMPLIED OR EXPRESS, * OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE or that * the use of it will not infringe on any third party's intellec- * tual property rights. * * You should have received a copy of the GNU Lesser General Public * License along with PCRE++. Copies can also be obtained from: * * http://www.gnu.org/licenses/lgpl.txt * * or by writing to: * * Free Software Foundation, Inc. * 59 Temple Place, Suite 330 * Boston, MA 02111-1307 * USA * * Or contact: * * "Thomas Linden" <tom@daemon.de> * * */ /* you need to include the pcre++ header file */ #include <pcre++.h> #include <iostream> void regex() { /* * define a string with a regular expression */ string expression = "([a-z]*) ([0-9]+)"; /* * this is the string in which we want to search */ string stuff = "hallo 11 robert"; cout << " searching in \"" << stuff << "\" for regex \"" << expression << "\":" << endl; /* * Create a new Pcre object, search case-insensitive ("i") */ Pcre reg(expression, "i"); /* * see if the expression matched */ if(reg.search(stuff) == true) { /* * see if the expression generated any substrings */ if(reg.num_matches >= 1) { /* * print out the number of substrings */ cout << " generated " << reg.matches() << " substrings:" << endl; /* * iterate over the matched sub strings */ for(int pos=0; pos < reg.matches(); pos++) { /* print out each substring */ cout << " substring " << pos << ": " << reg.get_match(pos); /* print out the start/end offset of the current substring within the searched string(stuff) */ cout << " (start: " << reg.get_match_start(pos) << ", end: " << reg.get_match_end(pos) << ")" << endl; } } else { /* * we had a match, but it generated no substrings, for whatever reason */ cout << " it matched, but there where no substrings." << endl; } } else { /* * no match at all */ cout << " didn't match." << endl; } } void replace() { /* * Sample of replace() usage */ string orig = "Hans ist 22 Jahre alt. Er ist 8 Jahre älter als Fred."; cout << " orig: " << orig << endl; /* * define a regex for digits (character class) */ Pcre p(" [0-9]+ "); /* * replace the 1st occurence of [0-9]+ with "zweiundzwanzig" */ string n = p.replace(orig, " zweiundzwanzig($1) "); /* * prints out: "Hans ist zweiundzwanzig Jahre alt. Er ist 8 Jahre älter als Fred." */ cout << " new: " << n << endl; } void replace_multi() { /* * Sample of replace() usage with multiple substrings */ string orig = " 08:23 "; cout << " orig: " << orig << endl; /* * create regex which, if it matches, creates 3 substrings */ Pcre reg(" ([0-9]+)(:)([0-9]+) ", "sig"); /* * remove $2 (":") * re-use $1 ("08") and $3 ("23") in the replace string */ string n = reg.replace(orig, "$1 Stunden und $3 Minuten"); /* * prints the result: "08 Stunden und 23 Minuten" */ cout << " new: " << n << endl; } void split() { /* * Sample of split() usage */ string sp_orig = "was21willst2387461du3alter!"; cout << " orig: " << sp_orig << endl; /* * define a regex for digits (character class) */ string delimiter = "[0-9]+"; /* * new Pcre object, match globally ("g" flag) */ Pcre S(delimiter, "g"); /* * split "was21willst2387461du3alter!" by digits */ Array splitted = S.split(sp_orig); /* * iterate over the resulting list */ cout << " splitted: "; for(ArrayIterator A = splitted.begin(); A != splitted.end(); ++A) cout << *A << " "; cout << endl; } void ex() { /* * Pcre::exception Test */ /* * this will generate only one substring, "This" */ Pcre ex("([a-z]+)", "i"); if(ex.search("This is a test.")) { cout << " trying to access a non-existing substring:" << endl; cout << " substring 2: " << ex.get_match(1) << endl; } } void mycopy() { /* * Sample use of copy contsructor and operator= */ cout << " initializing reg1(([a-z]+?)" << endl; Pcre reg1("^([a-z]+?)"); /* * create an empty Pcre objects */ Pcre reg2; /* * copy reg1 to reg2 (operator=) */ cout << " copying reg1 to new Pcre object reg2" << endl; reg2 = reg1; /* * using the copy constructor to initialize the 3rd object */ cout << " creating a new Pcre object reg3 from reg2" << endl; Pcre reg3(reg2); /* * doing regular stuff on reg3 */ if(reg3.search("anton")) cout << " string 'anton' matched using reg3 object" << endl; } int main() { /* * the Pcre class throws errors via exceptions */ try { cout << endl << "SEARCH() sample:" << endl; regex(); cout << endl << "REPLACE() sample:" << endl; replace(); cout << endl << "Multiple REPLACE() sample:" << endl; replace_multi(); cout << endl << "SPLIT() sample:" << endl; split(); cout << endl << "COPY+Operator sample:" << endl; mycopy(); cout << endl << "Pcre::exception test:" << endl; ex(); exit(0); } catch (Pcre::exception &E) { /* * the Pcre class has thrown an exception */ cerr << "Pcre++ error: " << E.what() << endl; exit(-1); } exit(0); }
Compile your programs which use the prce++ class using the following LDFLAGS:
g++ yourcode.o .. -L/path/to/the/lib -lpcrepp -o yourprogram
If you want to learn more about regular expressions which can be used with pcre++, then please read the following documentation: perlre - Perl regular expressions
The pcre library itself does also contain some usefull documentation, which maybe interesting for you: PCRE manual page
Definition at line 91 of file pcre++.h.
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Empty Constructor. Create a new empty Pcre object. This is the simplest constructor available, you might consider one of the other constructors as a better solution. You need to initialize thie Pcre object, if you use the empty constructor. You can use one of the two available operator= operators to assign it an expression or a Pcre copy.
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Constructor. Compile the given pattern. An Pcre object created this way can be used multiple times to do searches.
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Constructor. Compile the given pattern. An Pcre object created this way can be used multiple times to do searches.
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Copy Constructor Creates a new Pcre object of an existing one.
Definition at line 78 of file pcre++.cc. References _expression, _flags, case_t, and global_t. |
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Destructor. The desturcor will automatically invoked if the object is no more used. It frees all the memory allocated by pcre++. Definition at line 100 of file pcre++.cc. References num_matches. |
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Get a substring at a known position. This method throws an out-of-range exception if the given position is invalid.
string mysub = regex.get_match(1); Definition at line 265 of file pcre++.cc. References ArrayIterator, and num_matches. Referenced by replace(). |
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Get the end position of a substring within the searched string. This method returns the character position of the last character of a substring withing the searched string.
Pcre regex("([0-9]+)"); // search for numerical characters regex.search("The 11th september."); // do the search on this string string day = regex.get_match(1); // returns "11" int pos = regex.get_match_end(1); // returns 5, because "11" ends at the // 5th character inside the search string.
Definition at line 287 of file pcre++.cc. References num_matches. Referenced by replace(). |
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Get the length of a substring at a known position. This method throws an out-of-range exception if the given position is invalid.
Definition at line 301 of file pcre++.cc. References Array, ArrayIterator, and num_matches. |
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Get the start position of a substring within the searched string. This method returns the character position of the first character of a substring withing the searched string.
Pcre regex("([0-9]+)"); // search for numerical characters regex.search("The 11th september."); // do the search on this string string day = regex.get_match(1); // returns "11" int pos = regex.get_match_start(1); // returns 4, because "11" begins at the // 4th character inside the search string.
Definition at line 275 of file pcre++.cc. References num_matches. Referenced by replace(). |
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Return a vector of substrings, if any.
Definition at line 258 of file pcre++.cc. References Array. |
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Test if a search was successfull. This method must be invoked after calling search().
Definition at line 349 of file pcre++.h. References did_match. Referenced by replace(). |
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Get the number of substrings generated by pcre++.
Definition at line 354 of file pcre++.h. References Array, and num_matches. Referenced by replace(). |
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Operator =.
Definition at line 136 of file pcre++.cc. References _expression, _flags, case_t, did_match, global_t, and num_matches. |
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Operator =.
Pcre regex = "(A+?)"; @codeend; |
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Replace parts of a string using regular expressions. This method is the counterpart of the perl s/// operator. It replaces the substrings which matched the given regular expression (given to the constructor) with the supplied string.
Definition at line 422 of file pcre++.cc. References Array, get_match(), get_match_end(), get_match_start(), matched(), matches(), num_matches, and search(). |
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Do a search on the given string beginning at the given offset. This method does the actual search on the given string.
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Do a search on the given string. This method does the actual search on the given string.
Definition at line 209 of file pcre++.cc. References Array, did_match, and num_matches. Referenced by replace(). |
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split a string into pieces This method will split the given string into a vector of strings using the compiled expression (given to the constructor).
Definition at line 411 of file pcre++.cc. References Array. |
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split a string into pieces This method will split the given string into a vector of strings using the compiled expression (given to the constructor).
Definition at line 407 of file pcre++.cc. References Array. |
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split a string into pieces This method will split the given string into a vector of strings using the compiled expression (given to the constructor).
Definition at line 403 of file pcre++.cc. References Array. |
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split a string into pieces This method will split the given string into a vector of strings using the compiled expression (given to the constructor).
Definition at line 399 of file pcre++.cc. References Array. |
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split a string into pieces This method will split the given string into a vector of strings using the compiled expression (given to the constructor).
Definition at line 395 of file pcre++.cc. References Array. |
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true if the expression produced a match Definition at line 163 of file pcre++.h. Referenced by get_match(), get_match_end(), get_match_length(), get_match_start(), matches(), operator=(), replace(), search(), and ~Pcre(). |